fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
|
/*
|
|
|
|
|
* Simple file system for zoned block devices exposing zones as files.
|
|
|
|
|
*
|
|
|
|
|
* Copyright (C) 2019 Western Digital Corporation or its affiliates.
|
|
|
|
|
*/
|
|
|
|
|
#include <linux/module.h>
|
|
|
|
|
#include <linux/fs.h>
|
|
|
|
|
#include <linux/magic.h>
|
|
|
|
|
#include <linux/iomap.h>
|
|
|
|
|
#include <linux/init.h>
|
|
|
|
|
#include <linux/slab.h>
|
|
|
|
|
#include <linux/blkdev.h>
|
|
|
|
|
#include <linux/statfs.h>
|
|
|
|
|
#include <linux/writeback.h>
|
|
|
|
|
#include <linux/quotaops.h>
|
|
|
|
|
#include <linux/seq_file.h>
|
|
|
|
|
#include <linux/parser.h>
|
|
|
|
|
#include <linux/uio.h>
|
|
|
|
|
#include <linux/mman.h>
|
|
|
|
|
#include <linux/sched/mm.h>
|
|
|
|
|
#include <linux/crc32.h>
|
2020-05-12 16:55:54 +08:00
|
|
|
#include <linux/task_io_accounting_ops.h>
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
#include "zonefs.h"
|
|
|
|
|
|
2020-09-11 16:56:48 +08:00
|
|
|
static inline int zonefs_zone_mgmt(struct inode *inode,
|
|
|
|
|
enum req_opf op)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
lockdep_assert_held(&zi->i_truncate_mutex);
|
|
|
|
|
|
|
|
|
|
ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector,
|
|
|
|
|
zi->i_zone_size >> SECTOR_SHIFT, GFP_NOFS);
|
|
|
|
|
if (ret) {
|
|
|
|
|
zonefs_err(inode->i_sb,
|
|
|
|
|
"Zone management operation %s at %llu failed %d\n",
|
|
|
|
|
blk_op_str(op), zi->i_zsector, ret);
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
static inline void zonefs_i_size_write(struct inode *inode, loff_t isize)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
|
|
|
|
|
i_size_write(inode, isize);
|
|
|
|
|
/*
|
|
|
|
|
* A full zone is no longer open/active and does not need
|
|
|
|
|
* explicit closing.
|
|
|
|
|
*/
|
|
|
|
|
if (isize >= zi->i_max_size)
|
|
|
|
|
zi->i_flags &= ~ZONEFS_ZONE_OPEN;
|
|
|
|
|
}
|
|
|
|
|
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
|
|
|
|
|
unsigned int flags, struct iomap *iomap,
|
|
|
|
|
struct iomap *srcmap)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
loff_t isize;
|
|
|
|
|
|
|
|
|
|
/* All I/Os should always be within the file maximum size */
|
|
|
|
|
if (WARN_ON_ONCE(offset + length > zi->i_max_size))
|
|
|
|
|
return -EIO;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Sequential zones can only accept direct writes. This is already
|
|
|
|
|
* checked when writes are issued, so warn if we see a page writeback
|
|
|
|
|
* operation.
|
|
|
|
|
*/
|
|
|
|
|
if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
|
|
|
|
|
(flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))
|
|
|
|
|
return -EIO;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* For conventional zones, all blocks are always mapped. For sequential
|
|
|
|
|
* zones, all blocks after always mapped below the inode size (zone
|
|
|
|
|
* write pointer) and unwriten beyond.
|
|
|
|
|
*/
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
isize = i_size_read(inode);
|
|
|
|
|
if (offset >= isize)
|
|
|
|
|
iomap->type = IOMAP_UNWRITTEN;
|
|
|
|
|
else
|
|
|
|
|
iomap->type = IOMAP_MAPPED;
|
|
|
|
|
if (flags & IOMAP_WRITE)
|
|
|
|
|
length = zi->i_max_size - offset;
|
|
|
|
|
else
|
|
|
|
|
length = min(length, isize - offset);
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
|
|
|
|
|
iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
|
|
|
|
|
iomap->length = ALIGN(offset + length, sb->s_blocksize) - iomap->offset;
|
|
|
|
|
iomap->bdev = inode->i_sb->s_bdev;
|
|
|
|
|
iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct iomap_ops zonefs_iomap_ops = {
|
|
|
|
|
.iomap_begin = zonefs_iomap_begin,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int zonefs_readpage(struct file *unused, struct page *page)
|
|
|
|
|
{
|
|
|
|
|
return iomap_readpage(page, &zonefs_iomap_ops);
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-02 12:47:34 +08:00
|
|
|
static void zonefs_readahead(struct readahead_control *rac)
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
{
|
2020-06-02 12:47:34 +08:00
|
|
|
iomap_readahead(rac, &zonefs_iomap_ops);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Map blocks for page writeback. This is used only on conventional zone files,
|
|
|
|
|
* which implies that the page range can only be within the fixed inode size.
|
|
|
|
|
*/
|
|
|
|
|
static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
|
|
|
|
|
struct inode *inode, loff_t offset)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
|
|
|
|
|
if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV))
|
|
|
|
|
return -EIO;
|
|
|
|
|
if (WARN_ON_ONCE(offset >= i_size_read(inode)))
|
|
|
|
|
return -EIO;
|
|
|
|
|
|
|
|
|
|
/* If the mapping is already OK, nothing needs to be done */
|
|
|
|
|
if (offset >= wpc->iomap.offset &&
|
|
|
|
|
offset < wpc->iomap.offset + wpc->iomap.length)
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
return zonefs_iomap_begin(inode, offset, zi->i_max_size - offset,
|
|
|
|
|
IOMAP_WRITE, &wpc->iomap, NULL);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct iomap_writeback_ops zonefs_writeback_ops = {
|
|
|
|
|
.map_blocks = zonefs_map_blocks,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int zonefs_writepage(struct page *page, struct writeback_control *wbc)
|
|
|
|
|
{
|
|
|
|
|
struct iomap_writepage_ctx wpc = { };
|
|
|
|
|
|
|
|
|
|
return iomap_writepage(page, wbc, &wpc, &zonefs_writeback_ops);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_writepages(struct address_space *mapping,
|
|
|
|
|
struct writeback_control *wbc)
|
|
|
|
|
{
|
|
|
|
|
struct iomap_writepage_ctx wpc = { };
|
|
|
|
|
|
|
|
|
|
return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct address_space_operations zonefs_file_aops = {
|
|
|
|
|
.readpage = zonefs_readpage,
|
2020-06-02 12:47:34 +08:00
|
|
|
.readahead = zonefs_readahead,
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
.writepage = zonefs_writepage,
|
|
|
|
|
.writepages = zonefs_writepages,
|
|
|
|
|
.set_page_dirty = iomap_set_page_dirty,
|
|
|
|
|
.releasepage = iomap_releasepage,
|
|
|
|
|
.invalidatepage = iomap_invalidatepage,
|
|
|
|
|
.migratepage = iomap_migrate_page,
|
|
|
|
|
.is_partially_uptodate = iomap_is_partially_uptodate,
|
|
|
|
|
.error_remove_page = generic_error_remove_page,
|
|
|
|
|
.direct_IO = noop_direct_IO,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static void zonefs_update_stats(struct inode *inode, loff_t new_isize)
|
|
|
|
|
{
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
loff_t old_isize = i_size_read(inode);
|
|
|
|
|
loff_t nr_blocks;
|
|
|
|
|
|
|
|
|
|
if (new_isize == old_isize)
|
|
|
|
|
return;
|
|
|
|
|
|
|
|
|
|
spin_lock(&sbi->s_lock);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* This may be called for an update after an IO error.
|
|
|
|
|
* So beware of the values seen.
|
|
|
|
|
*/
|
|
|
|
|
if (new_isize < old_isize) {
|
|
|
|
|
nr_blocks = (old_isize - new_isize) >> sb->s_blocksize_bits;
|
|
|
|
|
if (sbi->s_used_blocks > nr_blocks)
|
|
|
|
|
sbi->s_used_blocks -= nr_blocks;
|
|
|
|
|
else
|
|
|
|
|
sbi->s_used_blocks = 0;
|
|
|
|
|
} else {
|
|
|
|
|
sbi->s_used_blocks +=
|
|
|
|
|
(new_isize - old_isize) >> sb->s_blocksize_bits;
|
|
|
|
|
if (sbi->s_used_blocks > sbi->s_blocks)
|
|
|
|
|
sbi->s_used_blocks = sbi->s_blocks;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
spin_unlock(&sbi->s_lock);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Check a zone condition and adjust its file inode access permissions for
|
|
|
|
|
* offline and readonly zones. Return the inode size corresponding to the
|
|
|
|
|
* amount of readable data in the zone.
|
|
|
|
|
*/
|
|
|
|
|
static loff_t zonefs_check_zone_condition(struct inode *inode,
|
2020-03-20 20:36:54 +08:00
|
|
|
struct blk_zone *zone, bool warn,
|
|
|
|
|
bool mount)
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
|
|
|
|
|
switch (zone->cond) {
|
|
|
|
|
case BLK_ZONE_COND_OFFLINE:
|
|
|
|
|
/*
|
|
|
|
|
* Dead zone: make the inode immutable, disable all accesses
|
|
|
|
|
* and set the file size to 0 (zone wp set to zone start).
|
|
|
|
|
*/
|
|
|
|
|
if (warn)
|
|
|
|
|
zonefs_warn(inode->i_sb, "inode %lu: offline zone\n",
|
|
|
|
|
inode->i_ino);
|
|
|
|
|
inode->i_flags |= S_IMMUTABLE;
|
|
|
|
|
inode->i_mode &= ~0777;
|
|
|
|
|
zone->wp = zone->start;
|
|
|
|
|
return 0;
|
|
|
|
|
case BLK_ZONE_COND_READONLY:
|
2020-03-20 20:36:54 +08:00
|
|
|
/*
|
|
|
|
|
* The write pointer of read-only zones is invalid. If such a
|
|
|
|
|
* zone is found during mount, the file size cannot be retrieved
|
|
|
|
|
* so we treat the zone as offline (mount == true case).
|
|
|
|
|
* Otherwise, keep the file size as it was when last updated
|
|
|
|
|
* so that the user can recover data. In both cases, writes are
|
|
|
|
|
* always disabled for the zone.
|
|
|
|
|
*/
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
if (warn)
|
|
|
|
|
zonefs_warn(inode->i_sb, "inode %lu: read-only zone\n",
|
|
|
|
|
inode->i_ino);
|
|
|
|
|
inode->i_flags |= S_IMMUTABLE;
|
2020-03-20 20:36:54 +08:00
|
|
|
if (mount) {
|
|
|
|
|
zone->cond = BLK_ZONE_COND_OFFLINE;
|
|
|
|
|
inode->i_mode &= ~0777;
|
|
|
|
|
zone->wp = zone->start;
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
inode->i_mode &= ~0222;
|
2020-03-20 20:36:54 +08:00
|
|
|
return i_size_read(inode);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
default:
|
|
|
|
|
if (zi->i_ztype == ZONEFS_ZTYPE_CNV)
|
|
|
|
|
return zi->i_max_size;
|
|
|
|
|
return (zone->wp - zone->start) << SECTOR_SHIFT;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
struct zonefs_ioerr_data {
|
|
|
|
|
struct inode *inode;
|
|
|
|
|
bool write;
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
|
|
|
|
|
void *data)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_ioerr_data *err = data;
|
|
|
|
|
struct inode *inode = err->inode;
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
loff_t isize, data_size;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Check the zone condition: if the zone is not "bad" (offline or
|
|
|
|
|
* read-only), read errors are simply signaled to the IO issuer as long
|
|
|
|
|
* as there is no inconsistency between the inode size and the amount of
|
|
|
|
|
* data writen in the zone (data_size).
|
|
|
|
|
*/
|
2020-03-20 20:36:54 +08:00
|
|
|
data_size = zonefs_check_zone_condition(inode, zone, true, false);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
isize = i_size_read(inode);
|
|
|
|
|
if (zone->cond != BLK_ZONE_COND_OFFLINE &&
|
|
|
|
|
zone->cond != BLK_ZONE_COND_READONLY &&
|
|
|
|
|
!err->write && isize == data_size)
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* At this point, we detected either a bad zone or an inconsistency
|
|
|
|
|
* between the inode size and the amount of data written in the zone.
|
|
|
|
|
* For the latter case, the cause may be a write IO error or an external
|
|
|
|
|
* action on the device. Two error patterns exist:
|
|
|
|
|
* 1) The inode size is lower than the amount of data in the zone:
|
|
|
|
|
* a write operation partially failed and data was writen at the end
|
|
|
|
|
* of the file. This can happen in the case of a large direct IO
|
|
|
|
|
* needing several BIOs and/or write requests to be processed.
|
|
|
|
|
* 2) The inode size is larger than the amount of data in the zone:
|
|
|
|
|
* this can happen with a deferred write error with the use of the
|
|
|
|
|
* device side write cache after getting successful write IO
|
|
|
|
|
* completions. Other possibilities are (a) an external corruption,
|
|
|
|
|
* e.g. an application reset the zone directly, or (b) the device
|
|
|
|
|
* has a serious problem (e.g. firmware bug).
|
|
|
|
|
*
|
|
|
|
|
* In all cases, warn about inode size inconsistency and handle the
|
|
|
|
|
* IO error according to the zone condition and to the mount options.
|
|
|
|
|
*/
|
|
|
|
|
if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && isize != data_size)
|
|
|
|
|
zonefs_warn(sb, "inode %lu: invalid size %lld (should be %lld)\n",
|
|
|
|
|
inode->i_ino, isize, data_size);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* First handle bad zones signaled by hardware. The mount options
|
|
|
|
|
* errors=zone-ro and errors=zone-offline result in changing the
|
|
|
|
|
* zone condition to read-only and offline respectively, as if the
|
|
|
|
|
* condition was signaled by the hardware.
|
|
|
|
|
*/
|
|
|
|
|
if (zone->cond == BLK_ZONE_COND_OFFLINE ||
|
|
|
|
|
sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL) {
|
|
|
|
|
zonefs_warn(sb, "inode %lu: read/write access disabled\n",
|
|
|
|
|
inode->i_ino);
|
|
|
|
|
if (zone->cond != BLK_ZONE_COND_OFFLINE) {
|
|
|
|
|
zone->cond = BLK_ZONE_COND_OFFLINE;
|
|
|
|
|
data_size = zonefs_check_zone_condition(inode, zone,
|
2020-03-20 20:36:54 +08:00
|
|
|
false, false);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
}
|
|
|
|
|
} else if (zone->cond == BLK_ZONE_COND_READONLY ||
|
|
|
|
|
sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO) {
|
|
|
|
|
zonefs_warn(sb, "inode %lu: write access disabled\n",
|
|
|
|
|
inode->i_ino);
|
|
|
|
|
if (zone->cond != BLK_ZONE_COND_READONLY) {
|
|
|
|
|
zone->cond = BLK_ZONE_COND_READONLY;
|
|
|
|
|
data_size = zonefs_check_zone_condition(inode, zone,
|
2020-03-20 20:36:54 +08:00
|
|
|
false, false);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
/*
|
|
|
|
|
* If the filesystem is mounted with the explicit-open mount option, we
|
|
|
|
|
* need to clear the ZONEFS_ZONE_OPEN flag if the zone transitioned to
|
|
|
|
|
* the read-only or offline condition, to avoid attempting an explicit
|
|
|
|
|
* close of the zone when the inode file is closed.
|
|
|
|
|
*/
|
|
|
|
|
if ((sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) &&
|
|
|
|
|
(zone->cond == BLK_ZONE_COND_OFFLINE ||
|
|
|
|
|
zone->cond == BLK_ZONE_COND_READONLY))
|
|
|
|
|
zi->i_flags &= ~ZONEFS_ZONE_OPEN;
|
|
|
|
|
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
/*
|
|
|
|
|
* If error=remount-ro was specified, any error result in remounting
|
|
|
|
|
* the volume as read-only.
|
|
|
|
|
*/
|
|
|
|
|
if ((sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO) && !sb_rdonly(sb)) {
|
|
|
|
|
zonefs_warn(sb, "remounting filesystem read-only\n");
|
|
|
|
|
sb->s_flags |= SB_RDONLY;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Update block usage stats and the inode size to prevent access to
|
|
|
|
|
* invalid data.
|
|
|
|
|
*/
|
|
|
|
|
zonefs_update_stats(inode, data_size);
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
zonefs_i_size_write(inode, data_size);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
zi->i_wpoffset = data_size;
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* When an file IO error occurs, check the file zone to see if there is a change
|
|
|
|
|
* in the zone condition (e.g. offline or read-only). For a failed write to a
|
|
|
|
|
* sequential zone, the zone write pointer position must also be checked to
|
|
|
|
|
* eventually correct the file size and zonefs inode write pointer offset
|
|
|
|
|
* (which can be out of sync with the drive due to partial write failures).
|
|
|
|
|
*/
|
2020-09-11 16:56:49 +08:00
|
|
|
static void __zonefs_io_error(struct inode *inode, bool write)
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
unsigned int noio_flag;
|
|
|
|
|
unsigned int nr_zones =
|
2020-07-21 20:10:26 +08:00
|
|
|
zi->i_zone_size >> (sbi->s_zone_sectors_shift + SECTOR_SHIFT);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
struct zonefs_ioerr_data err = {
|
|
|
|
|
.inode = inode,
|
|
|
|
|
.write = write,
|
|
|
|
|
};
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Memory allocations in blkdev_report_zones() can trigger a memory
|
|
|
|
|
* reclaim which may in turn cause a recursion into zonefs as well as
|
|
|
|
|
* struct request allocations for the same device. The former case may
|
|
|
|
|
* end up in a deadlock on the inode truncate mutex, while the latter
|
|
|
|
|
* may prevent IO forward progress. Executing the report zones under
|
|
|
|
|
* the GFP_NOIO context avoids both problems.
|
|
|
|
|
*/
|
|
|
|
|
noio_flag = memalloc_noio_save();
|
|
|
|
|
ret = blkdev_report_zones(sb->s_bdev, zi->i_zsector, nr_zones,
|
|
|
|
|
zonefs_io_error_cb, &err);
|
|
|
|
|
if (ret != nr_zones)
|
|
|
|
|
zonefs_err(sb, "Get inode %lu zone information failed %d\n",
|
|
|
|
|
inode->i_ino, ret);
|
|
|
|
|
memalloc_noio_restore(noio_flag);
|
2020-09-11 16:56:49 +08:00
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
2020-09-11 16:56:49 +08:00
|
|
|
static void zonefs_io_error(struct inode *inode, bool write)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
__zonefs_io_error(inode, write);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_truncate(struct inode *inode, loff_t isize)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
loff_t old_isize;
|
|
|
|
|
enum req_opf op;
|
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Only sequential zone files can be truncated and truncation is allowed
|
|
|
|
|
* only down to a 0 size, which is equivalent to a zone reset, and to
|
|
|
|
|
* the maximum file size, which is equivalent to a zone finish.
|
|
|
|
|
*/
|
|
|
|
|
if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
if (!isize)
|
|
|
|
|
op = REQ_OP_ZONE_RESET;
|
|
|
|
|
else if (isize == zi->i_max_size)
|
|
|
|
|
op = REQ_OP_ZONE_FINISH;
|
|
|
|
|
else
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
inode_dio_wait(inode);
|
|
|
|
|
|
|
|
|
|
/* Serialize against page faults */
|
|
|
|
|
down_write(&zi->i_mmap_sem);
|
|
|
|
|
|
|
|
|
|
/* Serialize against zonefs_iomap_begin() */
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
|
|
|
|
|
old_isize = i_size_read(inode);
|
|
|
|
|
if (isize == old_isize)
|
|
|
|
|
goto unlock;
|
|
|
|
|
|
2020-09-11 16:56:48 +08:00
|
|
|
ret = zonefs_zone_mgmt(inode, op);
|
|
|
|
|
if (ret)
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
goto unlock;
|
|
|
|
|
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
/*
|
|
|
|
|
* If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set,
|
|
|
|
|
* take care of open zones.
|
|
|
|
|
*/
|
|
|
|
|
if (zi->i_flags & ZONEFS_ZONE_OPEN) {
|
|
|
|
|
/*
|
|
|
|
|
* Truncating a zone to EMPTY or FULL is the equivalent of
|
|
|
|
|
* closing the zone. For a truncation to 0, we need to
|
|
|
|
|
* re-open the zone to ensure new writes can be processed.
|
|
|
|
|
* For a truncation to the maximum file size, the zone is
|
|
|
|
|
* closed and writes cannot be accepted anymore, so clear
|
|
|
|
|
* the open flag.
|
|
|
|
|
*/
|
|
|
|
|
if (!isize)
|
|
|
|
|
ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
|
|
|
|
|
else
|
|
|
|
|
zi->i_flags &= ~ZONEFS_ZONE_OPEN;
|
|
|
|
|
}
|
|
|
|
|
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
zonefs_update_stats(inode, isize);
|
|
|
|
|
truncate_setsize(inode, isize);
|
|
|
|
|
zi->i_wpoffset = isize;
|
|
|
|
|
|
|
|
|
|
unlock:
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
up_write(&zi->i_mmap_sem);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_inode_setattr(struct dentry *dentry, struct iattr *iattr)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = d_inode(dentry);
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
if (unlikely(IS_IMMUTABLE(inode)))
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
ret = setattr_prepare(dentry, iattr);
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Since files and directories cannot be created nor deleted, do not
|
|
|
|
|
* allow setting any write attributes on the sub-directories grouping
|
|
|
|
|
* files by zone type.
|
|
|
|
|
*/
|
|
|
|
|
if ((iattr->ia_valid & ATTR_MODE) && S_ISDIR(inode->i_mode) &&
|
|
|
|
|
(iattr->ia_mode & 0222))
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
if (((iattr->ia_valid & ATTR_UID) &&
|
|
|
|
|
!uid_eq(iattr->ia_uid, inode->i_uid)) ||
|
|
|
|
|
((iattr->ia_valid & ATTR_GID) &&
|
|
|
|
|
!gid_eq(iattr->ia_gid, inode->i_gid))) {
|
|
|
|
|
ret = dquot_transfer(inode, iattr);
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (iattr->ia_valid & ATTR_SIZE) {
|
|
|
|
|
ret = zonefs_file_truncate(inode, iattr->ia_size);
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
setattr_copy(inode, iattr);
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct inode_operations zonefs_file_inode_operations = {
|
|
|
|
|
.setattr = zonefs_inode_setattr,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end,
|
|
|
|
|
int datasync)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(file);
|
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
|
|
if (unlikely(IS_IMMUTABLE(inode)))
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Since only direct writes are allowed in sequential files, page cache
|
|
|
|
|
* flush is needed only for conventional zone files.
|
|
|
|
|
*/
|
|
|
|
|
if (ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_CNV)
|
|
|
|
|
ret = file_write_and_wait_range(file, start, end);
|
|
|
|
|
if (!ret)
|
2020-05-13 20:36:00 +08:00
|
|
|
ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
if (ret)
|
|
|
|
|
zonefs_io_error(inode, true);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static vm_fault_t zonefs_filemap_fault(struct vm_fault *vmf)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(file_inode(vmf->vma->vm_file));
|
|
|
|
|
vm_fault_t ret;
|
|
|
|
|
|
|
|
|
|
down_read(&zi->i_mmap_sem);
|
|
|
|
|
ret = filemap_fault(vmf);
|
|
|
|
|
up_read(&zi->i_mmap_sem);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(vmf->vma->vm_file);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
vm_fault_t ret;
|
|
|
|
|
|
|
|
|
|
if (unlikely(IS_IMMUTABLE(inode)))
|
|
|
|
|
return VM_FAULT_SIGBUS;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Sanity check: only conventional zone files can have shared
|
|
|
|
|
* writeable mappings.
|
|
|
|
|
*/
|
|
|
|
|
if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV))
|
|
|
|
|
return VM_FAULT_NOPAGE;
|
|
|
|
|
|
|
|
|
|
sb_start_pagefault(inode->i_sb);
|
|
|
|
|
file_update_time(vmf->vma->vm_file);
|
|
|
|
|
|
|
|
|
|
/* Serialize against truncates */
|
|
|
|
|
down_read(&zi->i_mmap_sem);
|
|
|
|
|
ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops);
|
|
|
|
|
up_read(&zi->i_mmap_sem);
|
|
|
|
|
|
|
|
|
|
sb_end_pagefault(inode->i_sb);
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct vm_operations_struct zonefs_file_vm_ops = {
|
|
|
|
|
.fault = zonefs_filemap_fault,
|
|
|
|
|
.map_pages = filemap_map_pages,
|
|
|
|
|
.page_mkwrite = zonefs_filemap_page_mkwrite,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
|
|
|
|
|
{
|
|
|
|
|
/*
|
|
|
|
|
* Conventional zones accept random writes, so their files can support
|
|
|
|
|
* shared writable mappings. For sequential zone files, only read
|
|
|
|
|
* mappings are possible since there are no guarantees for write
|
|
|
|
|
* ordering between msync() and page cache writeback.
|
|
|
|
|
*/
|
|
|
|
|
if (ZONEFS_I(file_inode(file))->i_ztype == ZONEFS_ZTYPE_SEQ &&
|
|
|
|
|
(vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
|
|
file_accessed(file);
|
|
|
|
|
vma->vm_ops = &zonefs_file_vm_ops;
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
|
|
|
|
|
{
|
|
|
|
|
loff_t isize = i_size_read(file_inode(file));
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Seeks are limited to below the zone size for conventional zones
|
|
|
|
|
* and below the zone write pointer for sequential zones. In both
|
|
|
|
|
* cases, this limit is the inode size.
|
|
|
|
|
*/
|
|
|
|
|
return generic_file_llseek_size(file, offset, whence, isize, isize);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
|
|
|
|
|
int error, unsigned int flags)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
|
|
|
|
|
if (error) {
|
|
|
|
|
zonefs_io_error(inode, true);
|
|
|
|
|
return error;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (size && zi->i_ztype != ZONEFS_ZTYPE_CNV) {
|
|
|
|
|
/*
|
|
|
|
|
* Note that we may be seeing completions out of order,
|
|
|
|
|
* but that is not a problem since a write completed
|
|
|
|
|
* successfully necessarily means that all preceding writes
|
|
|
|
|
* were also successful. So we can safely increase the inode
|
|
|
|
|
* size to the write end location.
|
|
|
|
|
*/
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
if (i_size_read(inode) < iocb->ki_pos + size) {
|
|
|
|
|
zonefs_update_stats(inode, iocb->ki_pos + size);
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
zonefs_i_size_write(inode, iocb->ki_pos + size);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
}
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct iomap_dio_ops zonefs_write_dio_ops = {
|
|
|
|
|
.end_io = zonefs_file_write_dio_end_io,
|
|
|
|
|
};
|
|
|
|
|
|
2020-05-12 16:55:54 +08:00
|
|
|
static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct block_device *bdev = inode->i_sb->s_bdev;
|
|
|
|
|
unsigned int max;
|
|
|
|
|
struct bio *bio;
|
|
|
|
|
ssize_t size;
|
|
|
|
|
int nr_pages;
|
|
|
|
|
ssize_t ret;
|
|
|
|
|
|
|
|
|
|
max = queue_max_zone_append_sectors(bdev_get_queue(bdev));
|
|
|
|
|
max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
|
|
|
|
|
iov_iter_truncate(from, max);
|
|
|
|
|
|
2020-07-16 18:37:23 +08:00
|
|
|
nr_pages = iov_iter_npages(from, BIO_MAX_PAGES);
|
|
|
|
|
if (!nr_pages)
|
|
|
|
|
return 0;
|
|
|
|
|
|
2020-05-12 16:55:54 +08:00
|
|
|
bio = bio_alloc_bioset(GFP_NOFS, nr_pages, &fs_bio_set);
|
|
|
|
|
if (!bio)
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
|
|
bio_set_dev(bio, bdev);
|
|
|
|
|
bio->bi_iter.bi_sector = zi->i_zsector;
|
|
|
|
|
bio->bi_write_hint = iocb->ki_hint;
|
|
|
|
|
bio->bi_ioprio = iocb->ki_ioprio;
|
|
|
|
|
bio->bi_opf = REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE;
|
|
|
|
|
if (iocb->ki_flags & IOCB_DSYNC)
|
|
|
|
|
bio->bi_opf |= REQ_FUA;
|
|
|
|
|
|
|
|
|
|
ret = bio_iov_iter_get_pages(bio, from);
|
|
|
|
|
if (unlikely(ret)) {
|
|
|
|
|
bio_io_error(bio);
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
size = bio->bi_iter.bi_size;
|
|
|
|
|
task_io_account_write(ret);
|
|
|
|
|
|
|
|
|
|
if (iocb->ki_flags & IOCB_HIPRI)
|
|
|
|
|
bio_set_polled(bio, iocb);
|
|
|
|
|
|
|
|
|
|
ret = submit_bio_wait(bio);
|
|
|
|
|
|
|
|
|
|
bio_put(bio);
|
|
|
|
|
|
|
|
|
|
zonefs_file_write_dio_end_io(iocb, size, ret, 0);
|
|
|
|
|
if (ret >= 0) {
|
|
|
|
|
iocb->ki_pos += size;
|
|
|
|
|
return size;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
/*
|
|
|
|
|
* Handle direct writes. For sequential zone files, this is the only possible
|
|
|
|
|
* write path. For these files, check that the user is issuing writes
|
|
|
|
|
* sequentially from the end of the file. This code assumes that the block layer
|
|
|
|
|
* delivers write requests to the device in sequential order. This is always the
|
|
|
|
|
* case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE
|
|
|
|
|
* elevator feature is being used (e.g. mq-deadline). The block layer always
|
|
|
|
|
* automatically select such an elevator for zoned block devices during the
|
|
|
|
|
* device initialization.
|
|
|
|
|
*/
|
|
|
|
|
static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
2020-05-12 16:55:54 +08:00
|
|
|
bool sync = is_sync_kiocb(iocb);
|
|
|
|
|
bool append = false;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
size_t count;
|
|
|
|
|
ssize_t ret;
|
|
|
|
|
|
|
|
|
|
/*
|
2020-02-21 22:37:23 +08:00
|
|
|
* For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
* as this can cause write reordering (e.g. the first aio gets EAGAIN
|
|
|
|
|
* on the inode lock but the second goes through but is now unaligned).
|
|
|
|
|
*/
|
2020-05-12 16:55:54 +08:00
|
|
|
if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !sync &&
|
2020-02-21 22:37:23 +08:00
|
|
|
(iocb->ki_flags & IOCB_NOWAIT))
|
|
|
|
|
return -EOPNOTSUPP;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
if (iocb->ki_flags & IOCB_NOWAIT) {
|
|
|
|
|
if (!inode_trylock(inode))
|
|
|
|
|
return -EAGAIN;
|
|
|
|
|
} else {
|
|
|
|
|
inode_lock(inode);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ret = generic_write_checks(iocb, from);
|
|
|
|
|
if (ret <= 0)
|
|
|
|
|
goto inode_unlock;
|
|
|
|
|
|
|
|
|
|
iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos);
|
|
|
|
|
count = iov_iter_count(from);
|
|
|
|
|
|
|
|
|
|
if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
goto inode_unlock;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Enforce sequential writes (append only) in sequential zones */
|
2020-05-12 16:55:54 +08:00
|
|
|
if (zi->i_ztype == ZONEFS_ZTYPE_SEQ) {
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
if (iocb->ki_pos != zi->i_wpoffset) {
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
goto inode_unlock;
|
|
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
2020-05-12 16:55:54 +08:00
|
|
|
append = sync;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
}
|
|
|
|
|
|
2020-05-12 16:55:54 +08:00
|
|
|
if (append)
|
|
|
|
|
ret = zonefs_file_dio_append(iocb, from);
|
|
|
|
|
else
|
|
|
|
|
ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
|
|
|
|
|
&zonefs_write_dio_ops, sync);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
|
|
|
|
|
(ret > 0 || ret == -EIOCBQUEUED)) {
|
|
|
|
|
if (ret > 0)
|
|
|
|
|
count = ret;
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
zi->i_wpoffset += count;
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
inode_unlock:
|
|
|
|
|
inode_unlock(inode);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
|
|
|
|
|
struct iov_iter *from)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
ssize_t ret;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Direct IO writes are mandatory for sequential zone files so that the
|
|
|
|
|
* write IO issuing order is preserved.
|
|
|
|
|
*/
|
|
|
|
|
if (zi->i_ztype != ZONEFS_ZTYPE_CNV)
|
|
|
|
|
return -EIO;
|
|
|
|
|
|
|
|
|
|
if (iocb->ki_flags & IOCB_NOWAIT) {
|
|
|
|
|
if (!inode_trylock(inode))
|
|
|
|
|
return -EAGAIN;
|
|
|
|
|
} else {
|
|
|
|
|
inode_lock(inode);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ret = generic_write_checks(iocb, from);
|
|
|
|
|
if (ret <= 0)
|
|
|
|
|
goto inode_unlock;
|
|
|
|
|
|
|
|
|
|
iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos);
|
|
|
|
|
|
|
|
|
|
ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops);
|
|
|
|
|
if (ret > 0)
|
|
|
|
|
iocb->ki_pos += ret;
|
|
|
|
|
else if (ret == -EIO)
|
|
|
|
|
zonefs_io_error(inode, true);
|
|
|
|
|
|
|
|
|
|
inode_unlock:
|
|
|
|
|
inode_unlock(inode);
|
|
|
|
|
if (ret > 0)
|
|
|
|
|
ret = generic_write_sync(iocb, ret);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
|
|
|
|
|
|
|
|
if (unlikely(IS_IMMUTABLE(inode)))
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
if (sb_rdonly(inode->i_sb))
|
|
|
|
|
return -EROFS;
|
|
|
|
|
|
|
|
|
|
/* Write operations beyond the zone size are not allowed */
|
|
|
|
|
if (iocb->ki_pos >= ZONEFS_I(inode)->i_max_size)
|
|
|
|
|
return -EFBIG;
|
|
|
|
|
|
2020-07-24 13:45:59 +08:00
|
|
|
if (iocb->ki_flags & IOCB_DIRECT) {
|
|
|
|
|
ssize_t ret = zonefs_file_dio_write(iocb, from);
|
|
|
|
|
if (ret != -ENOTBLK)
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
return zonefs_file_buffered_write(iocb, from);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size,
|
|
|
|
|
int error, unsigned int flags)
|
|
|
|
|
{
|
|
|
|
|
if (error) {
|
|
|
|
|
zonefs_io_error(file_inode(iocb->ki_filp), false);
|
|
|
|
|
return error;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct iomap_dio_ops zonefs_read_dio_ops = {
|
|
|
|
|
.end_io = zonefs_file_read_dio_end_io,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
|
|
|
|
|
{
|
|
|
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
loff_t isize;
|
|
|
|
|
ssize_t ret;
|
|
|
|
|
|
|
|
|
|
/* Offline zones cannot be read */
|
|
|
|
|
if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
|
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
|
|
if (iocb->ki_pos >= zi->i_max_size)
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
if (iocb->ki_flags & IOCB_NOWAIT) {
|
|
|
|
|
if (!inode_trylock_shared(inode))
|
|
|
|
|
return -EAGAIN;
|
|
|
|
|
} else {
|
|
|
|
|
inode_lock_shared(inode);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Limit read operations to written data */
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
isize = i_size_read(inode);
|
|
|
|
|
if (iocb->ki_pos >= isize) {
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
ret = 0;
|
|
|
|
|
goto inode_unlock;
|
|
|
|
|
}
|
|
|
|
|
iov_iter_truncate(to, isize - iocb->ki_pos);
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
|
|
|
|
|
if (iocb->ki_flags & IOCB_DIRECT) {
|
|
|
|
|
size_t count = iov_iter_count(to);
|
|
|
|
|
|
|
|
|
|
if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
goto inode_unlock;
|
|
|
|
|
}
|
|
|
|
|
file_accessed(iocb->ki_filp);
|
|
|
|
|
ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
|
|
|
|
|
&zonefs_read_dio_ops, is_sync_kiocb(iocb));
|
|
|
|
|
} else {
|
|
|
|
|
ret = generic_file_read_iter(iocb, to);
|
|
|
|
|
if (ret == -EIO)
|
|
|
|
|
zonefs_io_error(inode, false);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
inode_unlock:
|
|
|
|
|
inode_unlock_shared(inode);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
static inline bool zonefs_file_use_exp_open(struct inode *inode, struct file *file)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
|
|
|
|
|
|
|
|
|
|
if (!(sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN))
|
|
|
|
|
return false;
|
|
|
|
|
|
|
|
|
|
if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
|
|
|
|
|
return false;
|
|
|
|
|
|
|
|
|
|
if (!(file->f_mode & FMODE_WRITE))
|
|
|
|
|
return false;
|
|
|
|
|
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_open_zone(struct inode *inode)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
|
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
|
|
|
|
|
zi->i_wr_refcnt++;
|
|
|
|
|
if (zi->i_wr_refcnt == 1) {
|
|
|
|
|
|
|
|
|
|
if (atomic_inc_return(&sbi->s_open_zones) > sbi->s_max_open_zones) {
|
|
|
|
|
atomic_dec(&sbi->s_open_zones);
|
|
|
|
|
ret = -EBUSY;
|
|
|
|
|
goto unlock;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (i_size_read(inode) < zi->i_max_size) {
|
|
|
|
|
ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
|
|
|
|
|
if (ret) {
|
|
|
|
|
zi->i_wr_refcnt--;
|
|
|
|
|
atomic_dec(&sbi->s_open_zones);
|
|
|
|
|
goto unlock;
|
|
|
|
|
}
|
|
|
|
|
zi->i_flags |= ZONEFS_ZONE_OPEN;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
unlock:
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_open(struct inode *inode, struct file *file)
|
|
|
|
|
{
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
ret = generic_file_open(inode, file);
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
|
|
if (zonefs_file_use_exp_open(inode, file))
|
|
|
|
|
return zonefs_open_zone(inode);
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void zonefs_close_zone(struct inode *inode)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
|
|
mutex_lock(&zi->i_truncate_mutex);
|
|
|
|
|
zi->i_wr_refcnt--;
|
|
|
|
|
if (!zi->i_wr_refcnt) {
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* If the file zone is full, it is not open anymore and we only
|
|
|
|
|
* need to decrement the open count.
|
|
|
|
|
*/
|
|
|
|
|
if (!(zi->i_flags & ZONEFS_ZONE_OPEN))
|
|
|
|
|
goto dec;
|
|
|
|
|
|
|
|
|
|
ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
|
|
|
|
|
if (ret) {
|
|
|
|
|
__zonefs_io_error(inode, false);
|
|
|
|
|
/*
|
|
|
|
|
* Leaving zones explicitly open may lead to a state
|
|
|
|
|
* where most zones cannot be written (zone resources
|
|
|
|
|
* exhausted). So take preventive action by remounting
|
|
|
|
|
* read-only.
|
|
|
|
|
*/
|
|
|
|
|
if (zi->i_flags & ZONEFS_ZONE_OPEN &&
|
|
|
|
|
!(sb->s_flags & SB_RDONLY)) {
|
|
|
|
|
zonefs_warn(sb, "closing zone failed, remounting filesystem read-only\n");
|
|
|
|
|
sb->s_flags |= SB_RDONLY;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
zi->i_flags &= ~ZONEFS_ZONE_OPEN;
|
|
|
|
|
dec:
|
|
|
|
|
atomic_dec(&sbi->s_open_zones);
|
|
|
|
|
}
|
|
|
|
|
mutex_unlock(&zi->i_truncate_mutex);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_file_release(struct inode *inode, struct file *file)
|
|
|
|
|
{
|
|
|
|
|
/*
|
|
|
|
|
* If we explicitly open a zone we must close it again as well, but the
|
|
|
|
|
* zone management operation can fail (either due to an IO error or as
|
|
|
|
|
* the zone has gone offline or read-only). Make sure we don't fail the
|
|
|
|
|
* close(2) for user-space.
|
|
|
|
|
*/
|
|
|
|
|
if (zonefs_file_use_exp_open(inode, file))
|
|
|
|
|
zonefs_close_zone(inode);
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
static const struct file_operations zonefs_file_operations = {
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
.open = zonefs_file_open,
|
|
|
|
|
.release = zonefs_file_release,
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
.fsync = zonefs_file_fsync,
|
|
|
|
|
.mmap = zonefs_file_mmap,
|
|
|
|
|
.llseek = zonefs_file_llseek,
|
|
|
|
|
.read_iter = zonefs_file_read_iter,
|
|
|
|
|
.write_iter = zonefs_file_write_iter,
|
|
|
|
|
.splice_read = generic_file_splice_read,
|
|
|
|
|
.splice_write = iter_file_splice_write,
|
|
|
|
|
.iopoll = iomap_dio_iopoll,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static struct kmem_cache *zonefs_inode_cachep;
|
|
|
|
|
|
|
|
|
|
static struct inode *zonefs_alloc_inode(struct super_block *sb)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_inode_info *zi;
|
|
|
|
|
|
|
|
|
|
zi = kmem_cache_alloc(zonefs_inode_cachep, GFP_KERNEL);
|
|
|
|
|
if (!zi)
|
|
|
|
|
return NULL;
|
|
|
|
|
|
|
|
|
|
inode_init_once(&zi->i_vnode);
|
|
|
|
|
mutex_init(&zi->i_truncate_mutex);
|
|
|
|
|
init_rwsem(&zi->i_mmap_sem);
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
zi->i_wr_refcnt = 0;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
return &zi->i_vnode;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void zonefs_free_inode(struct inode *inode)
|
|
|
|
|
{
|
|
|
|
|
kmem_cache_free(zonefs_inode_cachep, ZONEFS_I(inode));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* File system stat.
|
|
|
|
|
*/
|
|
|
|
|
static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf)
|
|
|
|
|
{
|
|
|
|
|
struct super_block *sb = dentry->d_sb;
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
enum zonefs_ztype t;
|
|
|
|
|
u64 fsid;
|
|
|
|
|
|
|
|
|
|
buf->f_type = ZONEFS_MAGIC;
|
|
|
|
|
buf->f_bsize = sb->s_blocksize;
|
|
|
|
|
buf->f_namelen = ZONEFS_NAME_MAX;
|
|
|
|
|
|
|
|
|
|
spin_lock(&sbi->s_lock);
|
|
|
|
|
|
|
|
|
|
buf->f_blocks = sbi->s_blocks;
|
|
|
|
|
if (WARN_ON(sbi->s_used_blocks > sbi->s_blocks))
|
|
|
|
|
buf->f_bfree = 0;
|
|
|
|
|
else
|
|
|
|
|
buf->f_bfree = buf->f_blocks - sbi->s_used_blocks;
|
|
|
|
|
buf->f_bavail = buf->f_bfree;
|
|
|
|
|
|
|
|
|
|
for (t = 0; t < ZONEFS_ZTYPE_MAX; t++) {
|
|
|
|
|
if (sbi->s_nr_files[t])
|
|
|
|
|
buf->f_files += sbi->s_nr_files[t] + 1;
|
|
|
|
|
}
|
|
|
|
|
buf->f_ffree = 0;
|
|
|
|
|
|
|
|
|
|
spin_unlock(&sbi->s_lock);
|
|
|
|
|
|
|
|
|
|
fsid = le64_to_cpup((void *)sbi->s_uuid.b) ^
|
|
|
|
|
le64_to_cpup((void *)sbi->s_uuid.b + sizeof(u64));
|
2020-09-19 04:45:50 +08:00
|
|
|
buf->f_fsid = u64_to_fsid(fsid);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
enum {
|
|
|
|
|
Opt_errors_ro, Opt_errors_zro, Opt_errors_zol, Opt_errors_repair,
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
Opt_explicit_open, Opt_err,
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static const match_table_t tokens = {
|
|
|
|
|
{ Opt_errors_ro, "errors=remount-ro"},
|
|
|
|
|
{ Opt_errors_zro, "errors=zone-ro"},
|
|
|
|
|
{ Opt_errors_zol, "errors=zone-offline"},
|
|
|
|
|
{ Opt_errors_repair, "errors=repair"},
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
{ Opt_explicit_open, "explicit-open" },
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
{ Opt_err, NULL}
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int zonefs_parse_options(struct super_block *sb, char *options)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
substring_t args[MAX_OPT_ARGS];
|
|
|
|
|
char *p;
|
|
|
|
|
|
|
|
|
|
if (!options)
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
while ((p = strsep(&options, ",")) != NULL) {
|
|
|
|
|
int token;
|
|
|
|
|
|
|
|
|
|
if (!*p)
|
|
|
|
|
continue;
|
|
|
|
|
|
|
|
|
|
token = match_token(p, tokens, args);
|
|
|
|
|
switch (token) {
|
|
|
|
|
case Opt_errors_ro:
|
|
|
|
|
sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
|
|
|
|
|
sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_RO;
|
|
|
|
|
break;
|
|
|
|
|
case Opt_errors_zro:
|
|
|
|
|
sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
|
|
|
|
|
sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_ZRO;
|
|
|
|
|
break;
|
|
|
|
|
case Opt_errors_zol:
|
|
|
|
|
sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
|
|
|
|
|
sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_ZOL;
|
|
|
|
|
break;
|
|
|
|
|
case Opt_errors_repair:
|
|
|
|
|
sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
|
|
|
|
|
sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_REPAIR;
|
|
|
|
|
break;
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
case Opt_explicit_open:
|
|
|
|
|
sbi->s_mount_opts |= ZONEFS_MNTOPT_EXPLICIT_OPEN;
|
|
|
|
|
break;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
default:
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_show_options(struct seq_file *seq, struct dentry *root)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(root->d_sb);
|
|
|
|
|
|
|
|
|
|
if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO)
|
|
|
|
|
seq_puts(seq, ",errors=remount-ro");
|
|
|
|
|
if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO)
|
|
|
|
|
seq_puts(seq, ",errors=zone-ro");
|
|
|
|
|
if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL)
|
|
|
|
|
seq_puts(seq, ",errors=zone-offline");
|
|
|
|
|
if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_REPAIR)
|
|
|
|
|
seq_puts(seq, ",errors=repair");
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_remount(struct super_block *sb, int *flags, char *data)
|
|
|
|
|
{
|
|
|
|
|
sync_filesystem(sb);
|
|
|
|
|
|
|
|
|
|
return zonefs_parse_options(sb, data);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static const struct super_operations zonefs_sops = {
|
|
|
|
|
.alloc_inode = zonefs_alloc_inode,
|
|
|
|
|
.free_inode = zonefs_free_inode,
|
|
|
|
|
.statfs = zonefs_statfs,
|
|
|
|
|
.remount_fs = zonefs_remount,
|
|
|
|
|
.show_options = zonefs_show_options,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static const struct inode_operations zonefs_dir_inode_operations = {
|
|
|
|
|
.lookup = simple_lookup,
|
|
|
|
|
.setattr = zonefs_inode_setattr,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static void zonefs_init_dir_inode(struct inode *parent, struct inode *inode,
|
|
|
|
|
enum zonefs_ztype type)
|
|
|
|
|
{
|
|
|
|
|
struct super_block *sb = parent->i_sb;
|
|
|
|
|
|
|
|
|
|
inode->i_ino = blkdev_nr_zones(sb->s_bdev->bd_disk) + type + 1;
|
|
|
|
|
inode_init_owner(inode, parent, S_IFDIR | 0555);
|
|
|
|
|
inode->i_op = &zonefs_dir_inode_operations;
|
|
|
|
|
inode->i_fop = &simple_dir_operations;
|
|
|
|
|
set_nlink(inode, 2);
|
|
|
|
|
inc_nlink(parent);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void zonefs_init_file_inode(struct inode *inode, struct blk_zone *zone,
|
|
|
|
|
enum zonefs_ztype type)
|
|
|
|
|
{
|
|
|
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
struct zonefs_inode_info *zi = ZONEFS_I(inode);
|
|
|
|
|
|
|
|
|
|
inode->i_ino = zone->start >> sbi->s_zone_sectors_shift;
|
|
|
|
|
inode->i_mode = S_IFREG | sbi->s_perm;
|
|
|
|
|
|
|
|
|
|
zi->i_ztype = type;
|
|
|
|
|
zi->i_zsector = zone->start;
|
2020-07-21 20:10:26 +08:00
|
|
|
zi->i_zone_size = zone->len << SECTOR_SHIFT;
|
|
|
|
|
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
zi->i_max_size = min_t(loff_t, MAX_LFS_FILESIZE,
|
2020-07-21 20:10:26 +08:00
|
|
|
zone->capacity << SECTOR_SHIFT);
|
2020-03-20 20:36:54 +08:00
|
|
|
zi->i_wpoffset = zonefs_check_zone_condition(inode, zone, true, true);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
inode->i_uid = sbi->s_uid;
|
|
|
|
|
inode->i_gid = sbi->s_gid;
|
|
|
|
|
inode->i_size = zi->i_wpoffset;
|
2020-07-21 20:10:26 +08:00
|
|
|
inode->i_blocks = zi->i_max_size >> SECTOR_SHIFT;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
inode->i_op = &zonefs_file_inode_operations;
|
|
|
|
|
inode->i_fop = &zonefs_file_operations;
|
|
|
|
|
inode->i_mapping->a_ops = &zonefs_file_aops;
|
|
|
|
|
|
|
|
|
|
sb->s_maxbytes = max(zi->i_max_size, sb->s_maxbytes);
|
|
|
|
|
sbi->s_blocks += zi->i_max_size >> sb->s_blocksize_bits;
|
|
|
|
|
sbi->s_used_blocks += zi->i_wpoffset >> sb->s_blocksize_bits;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static struct dentry *zonefs_create_inode(struct dentry *parent,
|
|
|
|
|
const char *name, struct blk_zone *zone,
|
|
|
|
|
enum zonefs_ztype type)
|
|
|
|
|
{
|
|
|
|
|
struct inode *dir = d_inode(parent);
|
|
|
|
|
struct dentry *dentry;
|
|
|
|
|
struct inode *inode;
|
|
|
|
|
|
|
|
|
|
dentry = d_alloc_name(parent, name);
|
|
|
|
|
if (!dentry)
|
|
|
|
|
return NULL;
|
|
|
|
|
|
|
|
|
|
inode = new_inode(parent->d_sb);
|
|
|
|
|
if (!inode)
|
|
|
|
|
goto dput;
|
|
|
|
|
|
|
|
|
|
inode->i_ctime = inode->i_mtime = inode->i_atime = dir->i_ctime;
|
|
|
|
|
if (zone)
|
|
|
|
|
zonefs_init_file_inode(inode, zone, type);
|
|
|
|
|
else
|
|
|
|
|
zonefs_init_dir_inode(dir, inode, type);
|
|
|
|
|
d_add(dentry, inode);
|
|
|
|
|
dir->i_size++;
|
|
|
|
|
|
|
|
|
|
return dentry;
|
|
|
|
|
|
|
|
|
|
dput:
|
|
|
|
|
dput(dentry);
|
|
|
|
|
|
|
|
|
|
return NULL;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
struct zonefs_zone_data {
|
|
|
|
|
struct super_block *sb;
|
|
|
|
|
unsigned int nr_zones[ZONEFS_ZTYPE_MAX];
|
|
|
|
|
struct blk_zone *zones;
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Create a zone group and populate it with zone files.
|
|
|
|
|
*/
|
|
|
|
|
static int zonefs_create_zgroup(struct zonefs_zone_data *zd,
|
|
|
|
|
enum zonefs_ztype type)
|
|
|
|
|
{
|
|
|
|
|
struct super_block *sb = zd->sb;
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
struct blk_zone *zone, *next, *end;
|
|
|
|
|
const char *zgroup_name;
|
|
|
|
|
char *file_name;
|
|
|
|
|
struct dentry *dir;
|
|
|
|
|
unsigned int n = 0;
|
2020-07-20 16:52:52 +08:00
|
|
|
int ret;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
/* If the group is empty, there is nothing to do */
|
|
|
|
|
if (!zd->nr_zones[type])
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
file_name = kmalloc(ZONEFS_NAME_MAX, GFP_KERNEL);
|
|
|
|
|
if (!file_name)
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
|
|
if (type == ZONEFS_ZTYPE_CNV)
|
|
|
|
|
zgroup_name = "cnv";
|
|
|
|
|
else
|
|
|
|
|
zgroup_name = "seq";
|
|
|
|
|
|
|
|
|
|
dir = zonefs_create_inode(sb->s_root, zgroup_name, NULL, type);
|
2020-07-20 16:52:52 +08:00
|
|
|
if (!dir) {
|
|
|
|
|
ret = -ENOMEM;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
goto free;
|
2020-07-20 16:52:52 +08:00
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* The first zone contains the super block: skip it.
|
|
|
|
|
*/
|
|
|
|
|
end = zd->zones + blkdev_nr_zones(sb->s_bdev->bd_disk);
|
|
|
|
|
for (zone = &zd->zones[1]; zone < end; zone = next) {
|
|
|
|
|
|
|
|
|
|
next = zone + 1;
|
|
|
|
|
if (zonefs_zone_type(zone) != type)
|
|
|
|
|
continue;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* For conventional zones, contiguous zones can be aggregated
|
|
|
|
|
* together to form larger files. Note that this overwrites the
|
|
|
|
|
* length of the first zone of the set of contiguous zones
|
|
|
|
|
* aggregated together. If one offline or read-only zone is
|
|
|
|
|
* found, assume that all zones aggregated have the same
|
|
|
|
|
* condition.
|
|
|
|
|
*/
|
|
|
|
|
if (type == ZONEFS_ZTYPE_CNV &&
|
|
|
|
|
(sbi->s_features & ZONEFS_F_AGGRCNV)) {
|
|
|
|
|
for (; next < end; next++) {
|
|
|
|
|
if (zonefs_zone_type(next) != type)
|
|
|
|
|
break;
|
|
|
|
|
zone->len += next->len;
|
2020-07-21 20:10:26 +08:00
|
|
|
zone->capacity += next->capacity;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
if (next->cond == BLK_ZONE_COND_READONLY &&
|
|
|
|
|
zone->cond != BLK_ZONE_COND_OFFLINE)
|
|
|
|
|
zone->cond = BLK_ZONE_COND_READONLY;
|
|
|
|
|
else if (next->cond == BLK_ZONE_COND_OFFLINE)
|
|
|
|
|
zone->cond = BLK_ZONE_COND_OFFLINE;
|
|
|
|
|
}
|
2020-07-21 20:10:26 +08:00
|
|
|
if (zone->capacity != zone->len) {
|
|
|
|
|
zonefs_err(sb, "Invalid conventional zone capacity\n");
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
goto free;
|
|
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Use the file number within its group as file name.
|
|
|
|
|
*/
|
|
|
|
|
snprintf(file_name, ZONEFS_NAME_MAX - 1, "%u", n);
|
2020-07-20 16:52:52 +08:00
|
|
|
if (!zonefs_create_inode(dir, file_name, zone, type)) {
|
|
|
|
|
ret = -ENOMEM;
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
goto free;
|
2020-07-20 16:52:52 +08:00
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
n++;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
zonefs_info(sb, "Zone group \"%s\" has %u file%s\n",
|
|
|
|
|
zgroup_name, n, n > 1 ? "s" : "");
|
|
|
|
|
|
|
|
|
|
sbi->s_nr_files[type] = n;
|
|
|
|
|
ret = 0;
|
|
|
|
|
|
|
|
|
|
free:
|
|
|
|
|
kfree(file_name);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_get_zone_info_cb(struct blk_zone *zone, unsigned int idx,
|
|
|
|
|
void *data)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_zone_data *zd = data;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Count the number of usable zones: the first zone at index 0 contains
|
|
|
|
|
* the super block and is ignored.
|
|
|
|
|
*/
|
|
|
|
|
switch (zone->type) {
|
|
|
|
|
case BLK_ZONE_TYPE_CONVENTIONAL:
|
|
|
|
|
zone->wp = zone->start + zone->len;
|
|
|
|
|
if (idx)
|
|
|
|
|
zd->nr_zones[ZONEFS_ZTYPE_CNV]++;
|
|
|
|
|
break;
|
|
|
|
|
case BLK_ZONE_TYPE_SEQWRITE_REQ:
|
|
|
|
|
case BLK_ZONE_TYPE_SEQWRITE_PREF:
|
|
|
|
|
if (idx)
|
|
|
|
|
zd->nr_zones[ZONEFS_ZTYPE_SEQ]++;
|
|
|
|
|
break;
|
|
|
|
|
default:
|
|
|
|
|
zonefs_err(zd->sb, "Unsupported zone type 0x%x\n",
|
|
|
|
|
zone->type);
|
|
|
|
|
return -EIO;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
memcpy(&zd->zones[idx], zone, sizeof(struct blk_zone));
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int zonefs_get_zone_info(struct zonefs_zone_data *zd)
|
|
|
|
|
{
|
|
|
|
|
struct block_device *bdev = zd->sb->s_bdev;
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
zd->zones = kvcalloc(blkdev_nr_zones(bdev->bd_disk),
|
|
|
|
|
sizeof(struct blk_zone), GFP_KERNEL);
|
|
|
|
|
if (!zd->zones)
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
|
|
/* Get zones information from the device */
|
|
|
|
|
ret = blkdev_report_zones(bdev, 0, BLK_ALL_ZONES,
|
|
|
|
|
zonefs_get_zone_info_cb, zd);
|
|
|
|
|
if (ret < 0) {
|
|
|
|
|
zonefs_err(zd->sb, "Zone report failed %d\n", ret);
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (ret != blkdev_nr_zones(bdev->bd_disk)) {
|
|
|
|
|
zonefs_err(zd->sb, "Invalid zone report (%d/%u zones)\n",
|
|
|
|
|
ret, blkdev_nr_zones(bdev->bd_disk));
|
|
|
|
|
return -EIO;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static inline void zonefs_cleanup_zone_info(struct zonefs_zone_data *zd)
|
|
|
|
|
{
|
|
|
|
|
kvfree(zd->zones);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Read super block information from the device.
|
|
|
|
|
*/
|
|
|
|
|
static int zonefs_read_super(struct super_block *sb)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
struct zonefs_super *super;
|
|
|
|
|
u32 crc, stored_crc;
|
|
|
|
|
struct page *page;
|
|
|
|
|
struct bio_vec bio_vec;
|
|
|
|
|
struct bio bio;
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
page = alloc_page(GFP_KERNEL);
|
|
|
|
|
if (!page)
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
|
|
bio_init(&bio, &bio_vec, 1);
|
|
|
|
|
bio.bi_iter.bi_sector = 0;
|
|
|
|
|
bio.bi_opf = REQ_OP_READ;
|
|
|
|
|
bio_set_dev(&bio, sb->s_bdev);
|
|
|
|
|
bio_add_page(&bio, page, PAGE_SIZE, 0);
|
|
|
|
|
|
|
|
|
|
ret = submit_bio_wait(&bio);
|
|
|
|
|
if (ret)
|
|
|
|
|
goto free_page;
|
|
|
|
|
|
|
|
|
|
super = kmap(page);
|
|
|
|
|
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
if (le32_to_cpu(super->s_magic) != ZONEFS_MAGIC)
|
|
|
|
|
goto unmap;
|
|
|
|
|
|
|
|
|
|
stored_crc = le32_to_cpu(super->s_crc);
|
|
|
|
|
super->s_crc = 0;
|
|
|
|
|
crc = crc32(~0U, (unsigned char *)super, sizeof(struct zonefs_super));
|
|
|
|
|
if (crc != stored_crc) {
|
|
|
|
|
zonefs_err(sb, "Invalid checksum (Expected 0x%08x, got 0x%08x)",
|
|
|
|
|
crc, stored_crc);
|
|
|
|
|
goto unmap;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
sbi->s_features = le64_to_cpu(super->s_features);
|
|
|
|
|
if (sbi->s_features & ~ZONEFS_F_DEFINED_FEATURES) {
|
|
|
|
|
zonefs_err(sb, "Unknown features set 0x%llx\n",
|
|
|
|
|
sbi->s_features);
|
|
|
|
|
goto unmap;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (sbi->s_features & ZONEFS_F_UID) {
|
|
|
|
|
sbi->s_uid = make_kuid(current_user_ns(),
|
|
|
|
|
le32_to_cpu(super->s_uid));
|
|
|
|
|
if (!uid_valid(sbi->s_uid)) {
|
|
|
|
|
zonefs_err(sb, "Invalid UID feature\n");
|
|
|
|
|
goto unmap;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (sbi->s_features & ZONEFS_F_GID) {
|
|
|
|
|
sbi->s_gid = make_kgid(current_user_ns(),
|
|
|
|
|
le32_to_cpu(super->s_gid));
|
|
|
|
|
if (!gid_valid(sbi->s_gid)) {
|
|
|
|
|
zonefs_err(sb, "Invalid GID feature\n");
|
|
|
|
|
goto unmap;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (sbi->s_features & ZONEFS_F_PERM)
|
|
|
|
|
sbi->s_perm = le32_to_cpu(super->s_perm);
|
|
|
|
|
|
|
|
|
|
if (memchr_inv(super->s_reserved, 0, sizeof(super->s_reserved))) {
|
|
|
|
|
zonefs_err(sb, "Reserved area is being used\n");
|
|
|
|
|
goto unmap;
|
|
|
|
|
}
|
|
|
|
|
|
2020-04-23 23:32:11 +08:00
|
|
|
import_uuid(&sbi->s_uuid, super->s_uuid);
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
ret = 0;
|
|
|
|
|
|
|
|
|
|
unmap:
|
|
|
|
|
kunmap(page);
|
|
|
|
|
free_page:
|
|
|
|
|
__free_page(page);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Check that the device is zoned. If it is, get the list of zones and create
|
|
|
|
|
* sub-directories and files according to the device zone configuration and
|
|
|
|
|
* format options.
|
|
|
|
|
*/
|
|
|
|
|
static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_zone_data zd;
|
|
|
|
|
struct zonefs_sb_info *sbi;
|
|
|
|
|
struct inode *inode;
|
|
|
|
|
enum zonefs_ztype t;
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
if (!bdev_is_zoned(sb->s_bdev)) {
|
|
|
|
|
zonefs_err(sb, "Not a zoned block device\n");
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Initialize super block information: the maximum file size is updated
|
|
|
|
|
* when the zone files are created so that the format option
|
|
|
|
|
* ZONEFS_F_AGGRCNV which increases the maximum file size of a file
|
|
|
|
|
* beyond the zone size is taken into account.
|
|
|
|
|
*/
|
|
|
|
|
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
|
|
|
|
|
if (!sbi)
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
|
|
spin_lock_init(&sbi->s_lock);
|
|
|
|
|
sb->s_fs_info = sbi;
|
|
|
|
|
sb->s_magic = ZONEFS_MAGIC;
|
|
|
|
|
sb->s_maxbytes = 0;
|
|
|
|
|
sb->s_op = &zonefs_sops;
|
|
|
|
|
sb->s_time_gran = 1;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* The block size is set to the device physical sector size to ensure
|
|
|
|
|
* that write operations on 512e devices (512B logical block and 4KB
|
|
|
|
|
* physical block) are always aligned to the device physical blocks,
|
|
|
|
|
* as mandated by the ZBC/ZAC specifications.
|
|
|
|
|
*/
|
|
|
|
|
sb_set_blocksize(sb, bdev_physical_block_size(sb->s_bdev));
|
|
|
|
|
sbi->s_zone_sectors_shift = ilog2(bdev_zone_sectors(sb->s_bdev));
|
|
|
|
|
sbi->s_uid = GLOBAL_ROOT_UID;
|
|
|
|
|
sbi->s_gid = GLOBAL_ROOT_GID;
|
|
|
|
|
sbi->s_perm = 0640;
|
|
|
|
|
sbi->s_mount_opts = ZONEFS_MNTOPT_ERRORS_RO;
|
zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.
To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.
On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.
As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-11 16:56:50 +08:00
|
|
|
sbi->s_max_open_zones = bdev_max_open_zones(sb->s_bdev);
|
|
|
|
|
atomic_set(&sbi->s_open_zones, 0);
|
|
|
|
|
if (!sbi->s_max_open_zones &&
|
|
|
|
|
sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
|
|
|
|
|
zonefs_info(sb, "No open zones limit. Ignoring explicit_open mount option\n");
|
|
|
|
|
sbi->s_mount_opts &= ~ZONEFS_MNTOPT_EXPLICIT_OPEN;
|
|
|
|
|
}
|
fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).
As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.
Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.
The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
under a common sub-directory:
* For conventional zones, the sub-directory "cnv" is used.
* For sequential write zones, the sub-directory "seq" is used.
These two directories are the only directories that exist in zonefs.
Users cannot create other directories and cannot rename nor delete
the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
pointer position relative to the zone start sector. Truncating these
files is allowed only down to 0, in which case, the zone is reset to
rewind the zone write pointer position to the start of the zone, or
up to the zone size, in which case the file's zone is transitioned
to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
file zone size. Any access exceeding the zone size is failed with
the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
that can be issued to conventional zone files. Buffered, direct and
mmap read & write operations are accepted. For sequential zone files,
there are no restrictions on read operations, but all write
operations must be direct IO append writes. mmap write of sequential
files is not allowed.
Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
zones can be aggregated into a single larger file instead of the
default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
(root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
changed.
The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:
git@github.com:damien-lemoal/zonefs-tools.git.
zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.
Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.
$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).
$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0
This aggregated conventional zone file can be used as a regular file.
$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.
$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.
$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any
further write operation.
$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.
$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.
$ stat /mnt/seq/0
File: /mnt/seq/0
Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
Device: 870h/2160d Inode: 50431 Links: 1
Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.
This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-12-25 15:07:44 +08:00
|
|
|
|
|
|
|
|
ret = zonefs_read_super(sb);
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
|
|
ret = zonefs_parse_options(sb, data);
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
|
|
memset(&zd, 0, sizeof(struct zonefs_zone_data));
|
|
|
|
|
zd.sb = sb;
|
|
|
|
|
ret = zonefs_get_zone_info(&zd);
|
|
|
|
|
if (ret)
|
|
|
|
|
goto cleanup;
|
|
|
|
|
|
|
|
|
|
zonefs_info(sb, "Mounting %u zones",
|
|
|
|
|
blkdev_nr_zones(sb->s_bdev->bd_disk));
|
|
|
|
|
|
|
|
|
|
/* Create root directory inode */
|
|
|
|
|
ret = -ENOMEM;
|
|
|
|
|
inode = new_inode(sb);
|
|
|
|
|
if (!inode)
|
|
|
|
|
goto cleanup;
|
|
|
|
|
|
|
|
|
|
inode->i_ino = blkdev_nr_zones(sb->s_bdev->bd_disk);
|
|
|
|
|
inode->i_mode = S_IFDIR | 0555;
|
|
|
|
|
inode->i_ctime = inode->i_mtime = inode->i_atime = current_time(inode);
|
|
|
|
|
inode->i_op = &zonefs_dir_inode_operations;
|
|
|
|
|
inode->i_fop = &simple_dir_operations;
|
|
|
|
|
set_nlink(inode, 2);
|
|
|
|
|
|
|
|
|
|
sb->s_root = d_make_root(inode);
|
|
|
|
|
if (!sb->s_root)
|
|
|
|
|
goto cleanup;
|
|
|
|
|
|
|
|
|
|
/* Create and populate files in zone groups directories */
|
|
|
|
|
for (t = 0; t < ZONEFS_ZTYPE_MAX; t++) {
|
|
|
|
|
ret = zonefs_create_zgroup(&zd, t);
|
|
|
|
|
if (ret)
|
|
|
|
|
break;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
cleanup:
|
|
|
|
|
zonefs_cleanup_zone_info(&zd);
|
|
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static struct dentry *zonefs_mount(struct file_system_type *fs_type,
|
|
|
|
|
int flags, const char *dev_name, void *data)
|
|
|
|
|
{
|
|
|
|
|
return mount_bdev(fs_type, flags, dev_name, data, zonefs_fill_super);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void zonefs_kill_super(struct super_block *sb)
|
|
|
|
|
{
|
|
|
|
|
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
|
|
|
|
|
|
|
|
|
|
if (sb->s_root)
|
|
|
|
|
d_genocide(sb->s_root);
|
|
|
|
|
kill_block_super(sb);
|
|
|
|
|
kfree(sbi);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* File system definition and registration.
|
|
|
|
|
*/
|
|
|
|
|
static struct file_system_type zonefs_type = {
|
|
|
|
|
.owner = THIS_MODULE,
|
|
|
|
|
.name = "zonefs",
|
|
|
|
|
.mount = zonefs_mount,
|
|
|
|
|
.kill_sb = zonefs_kill_super,
|
|
|
|
|
.fs_flags = FS_REQUIRES_DEV,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
static int __init zonefs_init_inodecache(void)
|
|
|
|
|
{
|
|
|
|
|
zonefs_inode_cachep = kmem_cache_create("zonefs_inode_cache",
|
|
|
|
|
sizeof(struct zonefs_inode_info), 0,
|
|
|
|
|
(SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT),
|
|
|
|
|
NULL);
|
|
|
|
|
if (zonefs_inode_cachep == NULL)
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void zonefs_destroy_inodecache(void)
|
|
|
|
|
{
|
|
|
|
|
/*
|
|
|
|
|
* Make sure all delayed rcu free inodes are flushed before we
|
|
|
|
|
* destroy the inode cache.
|
|
|
|
|
*/
|
|
|
|
|
rcu_barrier();
|
|
|
|
|
kmem_cache_destroy(zonefs_inode_cachep);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int __init zonefs_init(void)
|
|
|
|
|
{
|
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
BUILD_BUG_ON(sizeof(struct zonefs_super) != ZONEFS_SUPER_SIZE);
|
|
|
|
|
|
|
|
|
|
ret = zonefs_init_inodecache();
|
|
|
|
|
if (ret)
|
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
|
|
ret = register_filesystem(&zonefs_type);
|
|
|
|
|
if (ret) {
|
|
|
|
|
zonefs_destroy_inodecache();
|
|
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void __exit zonefs_exit(void)
|
|
|
|
|
{
|
|
|
|
|
zonefs_destroy_inodecache();
|
|
|
|
|
unregister_filesystem(&zonefs_type);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
MODULE_AUTHOR("Damien Le Moal");
|
|
|
|
|
MODULE_DESCRIPTION("Zone file system for zoned block devices");
|
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
|
module_init(zonefs_init);
|
|
|
|
|
module_exit(zonefs_exit);
|