Functions generic_file_splice_read and generic_file_splice_write access
the pagecache directly. For block devices these functions must be locked
so that block size is not changed while they are in progress.
This patch is an additional fix for commit b87570f5d3 ("Fix a crash
when block device is read and block size is changed at the same time")
that locked aio_read, aio_write and mmap against block size change.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block IO update from Jens Axboe:
"Core block IO bits for 3.7. Not a huge round this time, it contains:
- First series from Kent cleaning up and generalizing bio allocation
and freeing.
- WRITE_SAME support from Martin.
- Mikulas patches to prevent O_DIRECT crashes when someone changes
the block size of a device.
- Make bio_split() work on data-less bio's (like trim/discards).
- A few other minor fixups."
Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew
Morton. It is due to the VM no longer using a prio-tree (see commit
6b2dbba8b6ac: "mm: replace vma prio_tree with an interval tree").
So make set_blocksize() use mapping_mapped() instead of open-coding the
internal VM knowledge that has changed.
* 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits)
block: makes bio_split support bio without data
scatterlist: refactor the sg_nents
scatterlist: add sg_nents
fs: fix include/percpu-rwsem.h export error
percpu-rw-semaphore: fix documentation typos
fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared
blockdev: turn a rw semaphore into a percpu rw semaphore
Fix a crash when block device is read and block size is changed at the same time
block: fix request_queue->flags initialization
block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()
block: ioctl to zero block ranges
block: Make blkdev_issue_zeroout use WRITE SAME
block: Implement support for WRITE SAME
block: Consolidate command flag and queue limit checks for merges
block: Clean up special command handling logic
block/blk-tag.c: Remove useless kfree
block: remove the duplicated setting for congestion_threshold
block: reject invalid queue attribute values
block: Add bio_clone_bioset(), bio_clone_kmalloc()
block: Consolidate bio_alloc_bioset(), bio_kmalloc()
...
blkdev_mmap() isn't used outside of fs/block_dev.c, mark it as
static.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This avoids cache line bouncing when many processes lock the semaphore
for read.
New percpu lock implementation
The lock consists of an array of percpu unsigned integers, a boolean
variable and a mutex.
When we take the lock for read, we enter rcu read section, check for a
"locked" variable. If it is false, we increase a percpu counter on the
current cpu and exit the rcu section. If "locked" is true, we exit the
rcu section, take the mutex and drop it (this waits until a writer
finished) and retry.
Unlocking for read just decreases percpu variable. Note that we can
unlock on a difference cpu than where we locked, in this case the
counter underflows. The sum of all percpu counters represents the number
of processes that hold the lock for read.
When we need to lock for write, we take the mutex, set "locked" variable
to true and synchronize rcu. Since RCU has been synchronized, no
processes can create new read locks. We wait until the sum of percpu
counters is zero - when it is, there are no readers in the critical
section.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The kernel may crash when block size is changed and I/O is issued
simultaneously.
Because some subsystems (udev or lvm) may read any block device anytime,
the bug actually puts any code that changes a block device size in
jeopardy.
The crash can be reproduced if you place "msleep(1000)" to
blkdev_get_blocks just before "bh->b_size = max_blocks <<
inode->i_blkbits;".
Then, run "dd if=/dev/ram0 of=/dev/null bs=4k count=1 iflag=direct"
While it is waiting in msleep, run "blockdev --setbsz 2048 /dev/ram0"
You get a BUG.
The direct and non-direct I/O is written with the assumption that block
size does not change. It doesn't seem practical to fix these crashes
one-by-one there may be many crash possibilities when block size changes
at a certain place and it is impossible to find them all and verify the
code.
This patch introduces a new rw-lock bd_block_size_semaphore. The lock is
taken for read during I/O. It is taken for write when changing block
size. Consequently, block size can't be changed while I/O is being
submitted.
For asynchronous I/O, the patch only prevents block size change while
the I/O is being submitted. The block size can change when the I/O is in
progress or when the I/O is being finished. This is acceptable because
there are no accesses to block size when asynchronous I/O is being
finished.
The patch prevents block size changing while the device is mapped with
mmap.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For regular file, write operaion used blk_plug function.But for block
file,write operation did not use blk_plug.
This patch is also for write-cache mode for block-device.
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
Pull writeback tree from Wu Fengguang:
"Mainly from Jan Kara to avoid iput() in the flusher threads."
* tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Avoid iput() from flusher thread
vfs: Rename end_writeback() to clear_inode()
vfs: Move waiting for inode writeback from end_writeback() to evict_inode()
writeback: Refactor writeback_single_inode()
writeback: Remove wb->list_lock from writeback_single_inode()
writeback: Separate inode requeueing after writeback
writeback: Move I_DIRTY_PAGES handling
writeback: Move requeueing when I_SYNC set to writeback_sb_inodes()
writeback: Move clearing of I_SYNC into inode_sync_complete()
writeback: initialize global_dirty_limit
fs: remove 8 bytes of padding from struct writeback_control on 64 bit builds
mm: page-writeback.c: local functions should not be exposed globally
Hi,
We have a bug report open where a squashfs image mounted on ppc64 would
exhibit errors due to trying to read beyond the end of the disk. It can
easily be reproduced by doing the following:
[root@ibm-p750e-02-lp3 ~]# ls -l install.img
-rw-r--r-- 1 root root 142032896 Apr 30 16:46 install.img
[root@ibm-p750e-02-lp3 ~]# mount -o loop ./install.img /mnt/test
[root@ibm-p750e-02-lp3 ~]# dd if=/dev/loop0 of=/dev/null
dd: reading `/dev/loop0': Input/output error
277376+0 records in
277376+0 records out
142016512 bytes (142 MB) copied, 0.9465 s, 150 MB/s
In dmesg, you'll find the following:
squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 43.106012] attempt to access beyond end of device
[ 43.106029] loop0: rw=0, want=277410, limit=277408
[ 43.106039] Buffer I/O error on device loop0, logical block 138704
[ 43.106053] attempt to access beyond end of device
[ 43.106057] loop0: rw=0, want=277412, limit=277408
[ 43.106061] Buffer I/O error on device loop0, logical block 138705
[ 43.106066] attempt to access beyond end of device
[ 43.106070] loop0: rw=0, want=277414, limit=277408
[ 43.106073] Buffer I/O error on device loop0, logical block 138706
[ 43.106078] attempt to access beyond end of device
[ 43.106081] loop0: rw=0, want=277416, limit=277408
[ 43.106085] Buffer I/O error on device loop0, logical block 138707
[ 43.106089] attempt to access beyond end of device
[ 43.106093] loop0: rw=0, want=277418, limit=277408
[ 43.106096] Buffer I/O error on device loop0, logical block 138708
[ 43.106101] attempt to access beyond end of device
[ 43.106104] loop0: rw=0, want=277420, limit=277408
[ 43.106108] Buffer I/O error on device loop0, logical block 138709
[ 43.106112] attempt to access beyond end of device
[ 43.106116] loop0: rw=0, want=277422, limit=277408
[ 43.106120] Buffer I/O error on device loop0, logical block 138710
[ 43.106124] attempt to access beyond end of device
[ 43.106128] loop0: rw=0, want=277424, limit=277408
[ 43.106131] Buffer I/O error on device loop0, logical block 138711
[ 43.106135] attempt to access beyond end of device
[ 43.106139] loop0: rw=0, want=277426, limit=277408
[ 43.106143] Buffer I/O error on device loop0, logical block 138712
[ 43.106147] attempt to access beyond end of device
[ 43.106151] loop0: rw=0, want=277428, limit=277408
[ 43.106154] Buffer I/O error on device loop0, logical block 138713
[ 43.106158] attempt to access beyond end of device
[ 43.106162] loop0: rw=0, want=277430, limit=277408
[ 43.106166] attempt to access beyond end of device
[ 43.106169] loop0: rw=0, want=277432, limit=277408
...
[ 43.106307] attempt to access beyond end of device
[ 43.106311] loop0: rw=0, want=277470, limit=2774
Squashfs manages to read in the end block(s) of the disk during the
mount operation. Then, when dd reads the block device, it leads to
block_read_full_page being called with buffers that are beyond end of
disk, but are marked as mapped. Thus, it would end up submitting read
I/O against them, resulting in the errors mentioned above. I fixed the
problem by modifying init_page_buffers to only set the buffer mapped if
it fell inside of i_size.
Cheers,
Jeff
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Nick Piggin <npiggin@kernel.dk>
--
Changes from v1->v2: re-used max_block, as suggested by Nick Piggin.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After we moved inode_sync_wait() from end_writeback() it doesn't make sense
to call the function end_writeback() anymore. Rename it to clear_inode()
which well says what the function really does - set I_CLEAR flag.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
- Move open-coded filesystem magic numbers into magic.h
- Rearrange magic.h so that the filesystem-related constants are grouped
together.
Signed-off-by: Muthukumar R <muthur@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since 2.6.39 (1196f8b), when a driver returns -ENOMEDIUM for open(),
__blkdev_get() calls rescan_partitions() to remove
in-kernel partition structures and raise KOBJ_CHANGE uevent.
However it ends up calling driver's revalidate_disk without open
and could cause oops.
In the case of SCSI:
process A process B
----------------------------------------------
sys_open
__blkdev_get
sd_open
returns -ENOMEDIUM
scsi_remove_device
<scsi_device torn down>
rescan_partitions
sd_revalidate_disk
<oops>
Oopses are reported here:
http://marc.info/?l=linux-scsi&m=132388619710052
This patch separates the partition invalidation from rescan_partitions()
and use it for -ENOMEDIUM case.
Reported-by: Huajun Li <huajun.li.lee@gmail.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Per akpm suggestions alter the use of the term flush to be
invalidate. The next patch will do this across all MM.
This change is completely cosmetic.
[v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 3]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@novell.com>
Reviewed-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Rik Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
[v10: Fixed fs: move code out of buffer.c conflict change]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This makes it possible to get from the inode to the request_queue with one
less cache miss. Used in followon optimization.
The livetime of the pointer is the same as the gendisk.
This assumes that the queue will always stay the same in the gendisk while
it's visible to block_devices. I think that's safe correct?
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.
Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else. Not to mention the removal of
boilerplate code from ->destroy_inode() instances...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
some stuff in there can actually become static; some belongs to pnode.h
as it's a private interface between namespace.c and pnode.c...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-3.2/drivers' of git://git.kernel.dk/linux-block: (30 commits)
virtio-blk: use ida to allocate disk index
hpsa: add small delay when using PCI Power Management to reset for kump
cciss: add small delay when using PCI Power Management to reset for kump
xen/blkback: Fix two races in the handling of barrier requests.
xen/blkback: Check for proper operation.
xen/blkback: Fix the inhibition to map pages when discarding sector ranges.
xen/blkback: Report VBD_WSECT (wr_sect) properly.
xen/blkback: Support 'feature-barrier' aka old-style BARRIER requests.
xen-blkfront: plug device number leak in xlblk_init() error path
xen-blkfront: If no barrier or flush is supported, use invalid operation.
xen-blkback: use kzalloc() in favor of kmalloc()+memset()
xen-blkback: fixed indentation and comments
xen-blkfront: fix a deadlock while handling discard response
xen-blkfront: Handle discard requests.
xen-blkback: Implement discard requests ('feature-discard')
xen-blkfront: add BLKIF_OP_DISCARD and discard request struct
drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd()
drivers/block/loop.c: emit uevent on auto release
drivers/block/cpqarray.c: use pci_dev->revision
loop: always allow userspace partitions and optionally support automatic scanning
...
Fic up trivial header file includsion conflict in drivers/block/loop.c
The following command sequence triggers an oops.
# mount /dev/sdb1 /mnt
# echo 1 > /sys/class/scsi_device/0\:0\:1\:0/device/delete
# umount /mnt
general protection fault: 0000 [#1] PREEMPT SMP
CPU 2
Modules linked in:
Pid: 791, comm: umount Not tainted 3.1.0-rc3-work+ #8 Bochs Bochs
RIP: 0010:[<ffffffff810d0879>] [<ffffffff810d0879>] __lock_acquire+0x389/0x1d60
...
Call Trace:
[<ffffffff810d2845>] lock_acquire+0x95/0x140
[<ffffffff81aed87b>] _raw_spin_lock+0x3b/0x50
[<ffffffff811573bc>] bdi_lock_two+0x5c/0x70
[<ffffffff811c2f6c>] bdev_inode_switch_bdi+0x4c/0xf0
[<ffffffff811c3fcb>] __blkdev_put+0x11b/0x1d0
[<ffffffff811c4010>] __blkdev_put+0x160/0x1d0
[<ffffffff811c40df>] blkdev_put+0x5f/0x190
[<ffffffff8118f18d>] kill_block_super+0x4d/0x80
[<ffffffff8118f4a5>] deactivate_locked_super+0x45/0x70
[<ffffffff8119003a>] deactivate_super+0x4a/0x70
[<ffffffff811ac4ad>] mntput_no_expire+0xed/0x130
[<ffffffff811acf2e>] sys_umount+0x7e/0x3a0
[<ffffffff81aeeeab>] system_call_fastpath+0x16/0x1b
This is because bdev holds on to disk but disk doesn't pin the
associated queue. If a SCSI device is removed while the device is
still open, the sdev puts the base reference to the queue on release.
When the bdev is finally released, the associated queue is already
gone along with the bdi and bdev_inode_switch_bdi() ends up
dereferencing already freed bdi.
Even if it were not for this bug, disk not holding onto the associated
queue is very unusual and error-prone.
Fix it by making add_disk() take an extra reference to its queue and
put it on disk_release() and ensuring that disk and its fops owner are
put in that order after all accesses to the disk and queue are
complete.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
On the last close of an 'md' device which as been stopped, the device
is destroyed and in particular the request_queue is freed. The free
is done in a separate thread so it might happen a short time later.
__blkdev_put calls bdev_inode_switch_bdi *after* ->release has been
called.
Since commit f758eeabeb
bdev_inode_switch_bdi will dereference the 'old' bdi, which lives
inside a request_queue, to get a spin lock. This causes the last
close on an md device to sometime take a spin_lock which lives in
freed memory - which results in an oops.
So move the called to bdev_inode_switch_bdi before the call to
->release.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
There are cases where suppressing partition scan is useful - e.g. for
lo devices and pseudo SATA devices which advertise to be a disk but
get upset on partition scan (some port multiplier control devices show
such behavior).
This patch adds GENHD_FL_NO_PART_SCAN which suppresses partition scan
regardless of the number of possible partitions. disk_partitionable()
is renamed to disk_part_scan_enabled() as suppressing partition scan
doesn't imply the device can't be partitioned using
BLKPG_ADD/DEL_PARTITION calls from userland. show_partition() now
directly tests disk_max_parts() to maintain backward-compatibility.
-v2: Updated to make it clear that only partition scan is suppressed
not partitioning itself as suggested by Kay Sievers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
bd_super is currently reset to NULL in kill_block_super() so we rely on previous
users of the block_device object to initialise this value for the next user.
This quirk was exposed on RHEL5 when a third party filesystem did not always use
kill_block_super() and therefore bd_super wasn't being reset when a block_device
object was recycled within the cache. This may not be a problem upstream but
makes sense to be defensive.
Signed-off-by: Lachlan McIlroy <lmcilroy@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-3.1/core' of git://git.kernel.dk/linux-block: (24 commits)
block: strict rq_affinity
backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu
block: fix patch import error in max_discard_sectors check
block: reorder request_queue to remove 64 bit alignment padding
CFQ: add think time check for group
CFQ: add think time check for service tree
CFQ: move think time check variables to a separate struct
fixlet: Remove fs_excl from struct task.
cfq: Remove special treatment for metadata rqs.
block: document blk_plug list access
block: avoid building too big plug list
compat_ioctl: fix make headers_check regression
block: eliminate potential for infinite loop in blkdev_issue_discard
compat_ioctl: fix warning caused by qemu
block: flush MEDIA_CHANGE from drivers on close(2)
blk-throttle: Make total_nr_queued unsigned
block: Add __attribute__((format(printf...) and fix fallout
fs/partitions/check.c: make local symbols static
block:remove some spare spaces in genhd.c
block:fix the comment error in blkdev.h
...
Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2. For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This converts everybody to handle SEEK_HOLE/SEEK_DATA properly. In some cases
we just return -EINVAL, in others we do the normal generic thing, and in others
we're simply making sure that the properly due-dilligence is done. For example
in NFS/CIFS we need to make sure the file size is update properly for the
SEEK_HOLE and SEEK_DATA case, but since it calls the generic llseek stuff itself
that is all we have to do. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently, only open(2) is defined as the 'clearing' point. It has
two roles - first, it's an acknowledgement from userland indicating
that the event has been received and kernel can clear pending states
and proceed to generate more events. Secondly, it's passed on to
device drivers as a hint indicating that a synchronization point has
been reached and it might want to take a deeper look at the device.
The latter currently is only used by sr which uses two different
mechanisms - GET_EVENT_MEDIA_STATUS_NOTIFICATION and TEST_UNIT_READY
to discover events, where the former is lighter weight and safe to be
used repeatedly but may not provide full coverage. Among other
things, GET_EVENT can't detect media removal while TUR can.
This patch makes close(2) - blkdev_put() - indicate clearing hint for
MEDIA_CHANGE to drivers. disk_check_events() is renamed to
disk_flush_events() and updated to take @mask for events to flush
which is or'd to ev->clearing and will be passed to the driver on the
next ->check_events() invocation.
This change makes sr generate MEDIA_CHANGE when media is ejected from
userland - e.g. with eject(1).
Note: Given the current usage, it seems @clearing hint is needlessly
complex. disk_clear_events() can simply clear all events and the hint
can be boolean @flush.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
6b4517a791 (block: implement bd_claiming and claiming block)
introduced claiming block to support O_EXCL blkdev opens properly.
bd_start_claiming() looks up the part 0 bdev and starts claiming
block. The function assumed that there is only one part 0 bdev and
always used bdget_disk(disk, 0) to look it up; unfortunately, this
isn't true for some drivers (floppy) which use multiple block devices
to denote different operating parameters for the same physical device.
There can be multiple part 0 bdev's for the same device number.
This incorrect assumption caused the wrong bdev to be used during
claiming leading to unbalanced bd_holders as reported in the following
bug.
https://bugzilla.kernel.org/show_bug.cgi?id=28522
This patch updates bd_start_claiming() such that it uses the bdev
specified as argument if its partno is zero.
Note that this means that different bdev's can be used for the same
device and O_EXCL check can be effectively bypassed. It has always
been broken that way and floppy is fortunately on its way out. Leave
that breakage alone.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Tested-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Cc: stable@kernel.org # >= v2.6.36
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Split the global inode_wb_list_lock into a per-bdi_writeback list_lock,
as it's currently the most contended lock in the system for metadata
heavy workloads. It won't help for single-filesystem workloads for
which we'll need the I/O-less balance_dirty_pages, but at least we
can dedicate a cpu to spinning on each bdi now for larger systems.
Based on earlier patches from Nick Piggin and Dave Chinner.
It reduces lock contentions to 1/4 in this test case:
10 HDD JBOD, 100 dd on each disk, XFS, 6GB ram
lock_stat version 0.3
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
vanilla 2.6.39-rc3:
inode_wb_list_lock: 42590 44433 0.12 147.74 144127.35 252274 886792 0.08 121.34 917211.23
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 34 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 12893 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 10702 [<ffffffff8115afef>] writeback_single_inode+0x16d/0x20a
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 19 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 5550 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 8511 [<ffffffff8115b4ad>] writeback_sb_inodes+0x10f/0x157
2.6.39-rc3 + patch:
&(&wb->list_lock)->rlock: 11383 11657 0.14 151.69 40429.51 90825 527918 0.11 145.90 556843.37
------------------------
&(&wb->list_lock)->rlock 10 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 1493 [<ffffffff8115b1ed>] writeback_inodes_wb+0x3d/0x150
&(&wb->list_lock)->rlock 3652 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
&(&wb->list_lock)->rlock 1412 [<ffffffff8115a38e>] writeback_single_inode+0x17f/0x223
------------------------
&(&wb->list_lock)->rlock 3 [<ffffffff8110b5af>] bdi_lock_two+0x46/0x4b
&(&wb->list_lock)->rlock 6 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 2061 [<ffffffff8115af97>] __mark_inode_dirty+0x173/0x1cf
&(&wb->list_lock)->rlock 2629 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
hughd@google.com: fix recursive lock when bdi_lock_two() is called with new the same as old
akpm@linux-foundation.org: cleanup bdev_inode_switch_bdi() comment
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
d4dc210f69 (block: don't block events on excl write for non-optical
devices) added dereferencing of bdev->bd_disk to test
GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE; however, bdev->bd_disk can be
%NULL if open failed which can lead to an oops.
Test the flag after testing open was successful, not before.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Miller <davem@davemloft.net>
Tested-by: David Miller <davem@davemloft.net>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
02e352287a (block: rescan partitions on invalidated devices on
-ENOMEDIA too) relocated partition rescan above explicit bd_set_size()
to simplify condition check. As rescan_partitions() does its own bdev
size setting, this doesn't break anything; however,
rescan_partitions() prints out the following messages when adjusting
bdev size, which can be confusing.
sda: detected capacity change from 0 to 146815737856
sdb: detected capacity change from 0 to 146815737856
This patch restores the original order and remove the warning
messages.
stable: Please apply together with 02e352287a (block: rescan
partitions on invalidated devices on -ENOMEDIA too).
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Tony Luck <tony.luck@gmail.com>
Tested-by: Tony Luck <tony.luck@gmail.com>
Cc: stable@kernel.org
Stable note: 2.6.39 only.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Disk event code automatically blocks events on excl write. This is
primarily to avoid issuing polling commands while burning is in
progress. This behavior doesn't fit other types of devices with
removeable media where polling commands don't have adverse side
effects and door locking usually doesn't exist.
This patch introduces new genhd flag which controls the auto-blocking
behavior and uses it to enable auto-blocking only on optical devices.
Note for stable: 2.6.38 and later only
Cc: stable@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
__blkdev_get() doesn't rescan partitions if disk->fops->open() fails,
which leads to ghost partition devices lingering after medimum removal
is known to both the kernel and userland. The behavior also creates a
subtle inconsistency where O_NONBLOCK open, which doesn't fail even if
there's no medium, clears the ghots partitions, which is exploited to
work around the problem from userland.
Fix it by updating __blkdev_get() to issue partition rescan after
-ENOMEDIA too.
This was reported in the following bz.
https://bugzilla.kernel.org/show_bug.cgi?id=13029
Note for stable: 2.6.38 and later only
Cc: stable@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Zeuthen <zeuthen@gmail.com>
Reported-by: Martin Pitt <martin.pitt@ubuntu.com>
Reported-by: Kay Sievers <kay.sievers@vrfy.org>
Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
fs: simplify iget & friends
fs: pull inode->i_lock up out of writeback_single_inode
fs: rename inode_lock to inode_hash_lock
fs: move i_wb_list out from under inode_lock
fs: move i_sb_list out from under inode_lock
fs: remove inode_lock from iput_final and prune_icache
fs: Lock the inode LRU list separately
fs: factor inode disposal
fs: protect inode->i_state with inode->i_lock
autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd()
autofs4 - remove autofs4_lock
autofs4 - fix d_manage() return on rcu-walk
autofs4 - fix autofs4_expire_indirect() traversal
autofs4 - fix dentry leak in autofs4_expire_direct()
autofs4 - reinstate last used update on access
vfs - check non-mountpoint dentry might block in __follow_mount_rcu()
Protect the inode writeback list with a new global lock
inode_wb_list_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the list.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.
This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.
Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
"disk" is always NULL when we goto out. There was a check for this
before, but it was removed in 69e02c59a7 "block: Don't check events
while open is in progress".
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@carl>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Not all block drivers clear events immediately after reporting. Some
do so in ->revalidate_disk() or other steps during ->open(). There is
a slim chance event poll may happen between the clearing event check
from check_disk_change() and the actual clearing of the events which
would result in spurious events.
Block event checks while block device open is in progress. There is
no need to kick explicit event check afterwards as events are always
checked during open.
-v2: The original patch could have called disk_unblock_events() with
an already released or %NULL @disk causing oops. Fixed by making
sure references are put after disk_unblock_events() is called.
It also makes the error path of __blkdev_get() a bit simpler.
This problem was reported by Jens.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
The block event mechanism currently always checks events when the
device is being closed regardless of the open mode. The intention was
to allow detection of EJECT_REQUEST when a device is closed whether
disk event polling is enabled or not.
This is unnecessary as, for devices of interest, events are checked
from either userland or kernel and in the former case ->check_events()
is performed on open of each poll attempt anyway. Furthermore, this
unconditional event check on close makes the code susceptible to event
loop if the block driver doesn't clear reported events correctly - an
event triggers userland to open and close the device which in turn
causes another event, rinse and repeat.
Check events on close only if it was blocked by excl write open.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Currently, disk_unblock_events() implicitly kick event check if the
block count reaches zero. This behavior is not described in the
comment and hinders with future changes. Make the unblocker
explicitly check events by calling disk_check_events() as necessary.
This patch doesn't cause any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Fix new kernel-doc warning in fs/block_dev.c:
Warning(fs/block_dev.c:937): No description found for parameter 'kill_dirty'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://neil.brown.name/md:
md: Fix - again - partition detection when array becomes active
Fix over-zealous flush_disk when changing device size.
md: avoid spinlock problem in blk_throtl_exit
md: correctly handle probe of an 'mdp' device.
md: don't set_capacity before array is active.
md: Fix raid1->raid0 takeover
The new implementation of bd_link_disk_holder() added by 49731baa41
(block: restore multiple bd_link_disk_holder() support) didn't get an
extra reference for the holder_dir kobject of the slave bdev; however,
bdev kills holder_dir on removal, not release, so if the slave bdev is
removed while there are holder links, the holder_dir will be destroyed
while there still are holder links, which leads to oops later when
bd_unlink_disk_order() tries to remove those links.
Make bd_link_disk_holder() grab an extra reference for the slave's
holder_dir and put it in bd_unlink_disk_holder().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Tested-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are two cases when we call flush_disk.
In one, the device has disappeared (check_disk_change) so any
data will hold becomes irrelevant.
In the oter, the device has changed size (check_disk_size_change)
so data we hold may be irrelevant.
In both cases it makes sense to discard any 'clean' buffers,
so they will be read back from the device if needed.
In the former case it makes sense to discard 'dirty' buffers
as there will never be anywhere safe to write the data. In the
second case it *does*not* make sense to discard dirty buffers
as that will lead to file system corruption when you simply enlarge
the containing devices.
flush_disk calls __invalidate_devices.
__invalidate_device calls both invalidate_inodes and invalidate_bdev.
invalidate_inodes *does* discard I_DIRTY inodes and this does lead
to fs corruption.
invalidate_bev *does*not* discard dirty pages, but I don't really care
about that at present.
So this patch adds a flag to __invalidate_device (calling it
__invalidate_device2) to indicate whether dirty buffers should be
killed, and this is passed to invalidate_inodes which can choose to
skip dirty inodes.
flusk_disk then passes true from check_disk_change and false from
check_disk_size_change.
dm avoids tripping over this problem by calling i_size_write directly
rathher than using check_disk_size_change.
md does use check_disk_size_change and so is affected.
This regression was introduced by commit 608aeef17a which causes
check_disk_size_change to call flush_disk, so it is suitable for any
kernel since 2.6.27.
Cc: stable@kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Andrew Patterson <andrew.patterson@hp.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NeilBrown <neilb@suse.de>
This reverts commit 75f1dc0d07 ("block: check bdev_read_only() from
blkdev_get()"). That commit added stricter checking to make sure
devices that were being used read-only were actually opened in that
mode.
It turns out that the change breaks a bunch of kernel code that opens
block devices. Affected systems include dm, md, and the loop device.
Because strict checking for read-only opens of block devices was not
done before this, the code that opens the devices was opening them
read-write even if they were being used read-only. Auditing all that
code will take time, and new userspace packages for dm, mdadm, etc.
will also be required.
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e09b457b (block: simplify holder symlink handling) incorrectly
assumed that there is only one link at maximum. dm may use multiple
links and expects block layer to track reference count for each link,
which is different from and unrelated to the exclusive device holder
identified by @holder when the device is opened.
Remove the single holder assumption and automatic removal of the link
and revive the per-link reference count tracking. The code
essentially behaves the same as before commit e09b457b sans the
unnecessary kobject reference count dancing.
While at it, note that this facility should not be used by anyone else
than the current ones. Sysfs symlinks shouldn't be abused like this
and the whole thing doesn't belong in the block layer at all.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Milan Broz <mbroz@redhat.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
block: ensure that completion error gets properly traced
blktrace: add missing probe argument to block_bio_complete
block cfq: don't use atomic_t for cfq_group
block cfq: don't use atomic_t for cfq_queue
block: trace event block fix unassigned field
block: add internal hd part table references
block: fix accounting bug on cross partition merges
kref: add kref_test_and_get
bio-integrity: mark kintegrityd_wq highpri and CPU intensive
block: make kblockd_workqueue smarter
Revert "sd: implement sd_check_events()"
block: Clean up exit_io_context() source code.
Fix compile warnings due to missing removal of a 'ret' variable
fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
cfq-iosched: don't check cfqg in choose_service_tree()
fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
cdrom: export cdrom_check_events()
sd: implement sd_check_events()
sr: implement sr_check_events()
...
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Currently, media presence polling for removeable block devices is done
from userland. There are several issues with this.
* Polling is done by periodically opening the device. For SCSI
devices, the command sequence generated by such action involves a
few different commands including TEST_UNIT_READY. This behavior,
while perfectly legal, is different from Windows which only issues
single command, GET_EVENT_STATUS_NOTIFICATION. Unfortunately, some
ATAPI devices lock up after being periodically queried such command
sequences.
* There is no reliable and unintrusive way for a userland program to
tell whether the target device is safe for media presence polling.
For example, polling for media presence during an on-going burning
session can make it fail. The polling program can avoid this by
opening the device with O_EXCL but then it risks making a valid
exclusive user of the device fail w/ -EBUSY.
* Userland polling is unnecessarily heavy and in-kernel implementation
is lighter and better coordinated (workqueue, timer slack).
This patch implements framework for in-kernel disk event handling,
which includes media presence polling.
* bdops->check_events() is added, which supercedes ->media_changed().
It should check whether there's any pending event and return if so.
Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and
DISK_EVENT_EJECT_REQUEST. ->check_events() is guaranteed not to be
called parallelly.
* gendisk->events and ->async_events are added. These should be
initialized by block driver before passing the device to add_disk().
The former contains the mask of all supported events and the latter
the mask of all events which the device can report without polling.
/sys/block/*/events[_async] export these to userland.
* Kernel parameter block.events_dfl_poll_msecs controls the system
polling interval (default is 0 which means disable) and
/sys/block/*/events_poll_msecs control polling intervals for
individual devices (default is -1 meaning use system setting). Note
that if a device can report all supported events asynchronously and
its polling interval isn't explicitly set, the device won't be
polled regardless of the system polling interval.
* If a device is opened exclusively with write access, event checking
is automatically disabled until all write exclusive accesses are
released.
* There are event 'clearing' events. For example, both of currently
defined events are cleared after the device has been successfully
opened. This information is passed to ->check_events() callback
using @clearing argument as a hint.
* Event checking is always performed from system_nrt_wq and timer
slack is set to 25% for polling.
* Nothing changes for drivers which implement ->media_changed() but
not ->check_events(). Going forward, all drivers will be converted
to ->check_events() and ->media_change() will be dropped.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The big kernel lock has been removed from all these files at some point,
leaving only the #include.
Remove this too as a cleanup.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().
blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.
All users are converted. Most conversions are mechanical and don't
introduce any behavior difference. There are several exceptions.
* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
reason to OR it explicitly on blkdev_put().
* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
sb->s_mode.
* With the above changes, sb->s_mode now always should contain
FMODE_EXCL. WARN_ON_ONCE() added to kill_block_super() to detect
errors.
The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
bdev read-only status can be queried using bdev_read_only() and may
change while the device is being opened. Enforce it by checking it
from blkdev_get() after open succeeds.
This makes bdev_read_only() check in open_bdev_exclusive() and
fsg_lun_open() unnecessary. Drop them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-usb@vger.kernel.org
With claim/release rolled into blkdev_get/put(), there's no reason to
keep bd_abort/finish_claim(), __bd_claim() and bd_release() as
separate functions. It only makes the code difficult to follow.
Collapse them into blkdev_get/put(). This will ease future changes
around claim/release.
Signed-off-by: Tejun Heo <tj@kernel.org>
Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.
* blkdev_get/put() are the primary open and close functions.
* bd_claim/release() deal with exclusive open.
* open/close_bdev_exclusive() are combination of open and claim and
the other way around, respectively.
* bd_link/unlink_disk_holder() to create and remove holder/slave
symlinks.
* open_by_devnum() wraps bdget() + blkdev_get().
The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access. Reorganize the interface such that,
* blkdev_get() is extended to include exclusive access management.
@holder argument is added and, if is @FMODE_EXCL specified, it will
gain exclusive access atomically w.r.t. other exclusive accesses.
* blkdev_put() is similarly extended. It now takes @mode argument and
if @FMODE_EXCL is set, it releases an exclusive access. Also, when
the last exclusive claim is released, the holder/slave symlinks are
removed automatically.
* bd_claim/release() and close_bdev_exclusive() are no longer
necessary and either made static or removed.
* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
is no longer necessary and removed.
* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
and blkdev_get(). It also has an unexpected extra bdev_read_only()
test which probably should be moved into blkdev_get().
* open_by_devnum() is modified to take @holder argument and pass it to
blkdev_get().
Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should). This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.
open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features. Well, let's leave them for another day.
Most conversions are straight-forward. drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen <leochen@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Joern Engel <joern@logfs.org>
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Code to manage symlinks in /sys/block/*/{holders|slaves} are overly
complex with multiple holder considerations, redundant extra
references to all involved kobjects, unused generic kobject holder
support and unnecessary mixup with bd_claim/release functionalities.
Strip it down to what's necessary (single gendisk holder) and make it
use a separate interface. This is a step for cleaning up
bd_claim/release. This patch makes dm-table slightly more complex but
it will be simplified again with further changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
The use of the same inode list structure (inode->i_list) for two
different list constructs with different lifecycles and purposes
makes it impossible to separate the locking of the different
operations. Therefore, to enable the separation of the locking of
the writeback and reclaim lists, split the inode->i_list into two
separate lists dedicated to their specific tracking functions.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
bdev inodes can remain dirty even after their last close. Hence the
BDI associated with the bdev->inode gets modified duringthe last
close to point to the default BDI. However, the bdev inode still
needs to be moved to the dirty lists of the new BDI, otherwise it
will corrupt the writeback list is was left on.
Add a new function bdev_inode_switch_bdi() to move all the bdi state
from the old bdi to the new one safely. This is only a temporary
measure until the bdev inode<->bdi lifecycle problems are sorted
out.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All the blkdev_issue_* helpers can only sanely be used for synchronous
caller. To issue cache flushes or barriers asynchronously the caller needs
to set up a bio by itself with a completion callback to move the asynchronous
state machine ahead. So drop the BLKDEV_IFL_WAIT flag that is always
specified when calling blkdev_issue_* and also remove the now unused flags
argument to blkdev_issue_flush and blkdev_issue_zeroout. For
blkdev_issue_discard we need to keep it for the secure discard flag, which
gains a more descriptive name and loses the bitops vs flag confusion.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The cgroup device whitelist code gets confused when trying to grant
permission to a disk partition that is not currently open. Part of
blkdev_open() includes __blkdev_get() on the whole disk.
Basically, the only ways to reliably allow a cgroup access to a partition
on a block device when using the whitelist are to 1) also give it access
to the whole block device or 2) make sure the partition is already open in
a different context.
The patch avoids the cgroup check for the whole disk case when opening a
partition.
Addresses https://bugzilla.redhat.com/show_bug.cgi?id=589662
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Serge E. Hallyn <serue@us.ibm.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Daniel P. Berrange" <berrange@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block: (149 commits)
block: make sure that REQ_* types are seen even with CONFIG_BLOCK=n
xen-blkfront: fix missing out label
blkdev: fix blkdev_issue_zeroout return value
block: update request stacking methods to support discards
block: fix missing export of blk_types.h
writeback: fix bad _bh spinlock nesting
drbd: revert "delay probes", feature is being re-implemented differently
drbd: Initialize all members of sync_conf to their defaults [Bugz 315]
drbd: Disable delay probes for the upcomming release
writeback: cleanup bdi_register
writeback: add new tracepoints
writeback: remove unnecessary init_timer call
writeback: optimize periodic bdi thread wakeups
writeback: prevent unnecessary bdi threads wakeups
writeback: move bdi threads exiting logic to the forker thread
writeback: restructure bdi forker loop a little
writeback: move last_active to bdi
writeback: do not remove bdi from bdi_list
writeback: simplify bdi code a little
writeback: do not lose wake-ups in bdi threads
...
Fixed up pretty trivial conflicts in drivers/block/virtio_blk.c and
drivers/scsi/scsi_error.c as per Jens.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (96 commits)
no need for list_for_each_entry_safe()/resetting with superblock list
Fix sget() race with failing mount
vfs: don't hold s_umount over close_bdev_exclusive() call
sysv: do not mark superblock dirty on remount
sysv: do not mark superblock dirty on mount
btrfs: remove junk sb_dirt change
BFS: clean up the superblock usage
AFFS: wait for sb synchronization when needed
AFFS: clean up dirty flag usage
cifs: truncate fallout
mbcache: fix shrinker function return value
mbcache: Remove unused features
add f_flags to struct statfs(64)
pass a struct path to vfs_statfs
update VFS documentation for method changes.
All filesystems that need invalidate_inode_buffers() are doing that explicitly
convert remaining ->clear_inode() to ->evict_inode()
Make ->drop_inode() just return whether inode needs to be dropped
fs/inode.c:clear_inode() is gone
fs/inode.c:evict() doesn't care about delete vs. non-delete paths now
...
Fix up trivial conflicts in fs/nilfs2/super.c
Move the call to vmtruncate to get rid of accessive blocks to the callers
in preparation of the new truncate sequence and rename the non-truncating
version to block_write_begin.
While we're at it also remove several unused arguments to block_write_begin.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Move the call to vmtruncate to get rid of accessive blocks to the callers
in prepearation of the new truncate calling sequence. This was only done
for DIO_LOCKING filesystems, so the __blockdev_direct_IO_newtrunc variant
was not needed anyway. Get rid of blockdev_direct_IO_no_locking and
its _newtrunc variant while at it as just opencoding the two additional
paramters is shorted than the name suffix.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.
This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.
The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.
Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
bd_prepare_to_claim() incorrectly allowed multiple attempts for
exclusive open to progress in parallel if the attempting holders are
identical. This triggered BUG_ON() as reported in the following bug.
https://bugzilla.kernel.org/show_bug.cgi?id=16393
__bd_abort_claiming() is used to finish claiming blocks and doesn't
work if multiple openers are inside a claiming block. Allowing
multiple parallel open attempts to continue doesn't gain anything as
those are serialized down in the call chain anyway. Fix it by always
allowing only single open attempt in a claiming block.
This problem can easily be reproduced by adding a delay after
bd_prepare_to_claim() and attempting to mount two partitions of a
disk.
stable: only applicable to v2.6.35
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We do the same BUG_ON() just a line later when calling into
__bd_abort_claiming().
Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
I don't like the subtle multi-context code in bd_claim (ie. detects where it
has been called based on bd_claiming). It seems clearer to just require a new
function to finish a 2-part claim.
Also improve commentary in bd_start_claiming as to how it should
be used.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
bd_start_claiming has an unbalanced module_put introduced in 6b4517a79.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Convert simple filesystems: ramfs, configfs, sysfs, block_dev to new truncate
sequence.
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (69 commits)
fix handling of offsets in cris eeprom.c, get rid of fake on-stack files
get rid of home-grown mutex in cris eeprom.c
switch ecryptfs_write() to struct inode *, kill on-stack fake files
switch ecryptfs_get_locked_page() to struct inode *
simplify access to ecryptfs inodes in ->readpage() and friends
AFS: Don't put struct file on the stack
Ban ecryptfs over ecryptfs
logfs: replace inode uid,gid,mode initialization with helper function
ufs: replace inode uid,gid,mode initialization with helper function
udf: replace inode uid,gid,mode init with helper
ubifs: replace inode uid,gid,mode initialization with helper function
sysv: replace inode uid,gid,mode initialization with helper function
reiserfs: replace inode uid,gid,mode initialization with helper function
ramfs: replace inode uid,gid,mode initialization with helper function
omfs: replace inode uid,gid,mode initialization with helper function
bfs: replace inode uid,gid,mode initialization with helper function
ocfs2: replace inode uid,gid,mode initialization with helper function
nilfs2: replace inode uid,gid,mode initialization with helper function
minix: replace inode uid,gid,mode init with helper
ext4: replace inode uid,gid,mode init with helper
...
Trivial conflict in fs/fs-writeback.c (mark bitfields unsigned)
Currently the way we do freezing is by passing sb>s_bdev to freeze_bdev and then
letting it do all the work. But freezing is more of an fs thing, and doesn't
really have much to do with the bdev at all, all the work gets done with the
super. In btrfs we do not populate s_bdev, since we can have multiple bdev's
for one fs and setting s_bdev makes removing devices from a pool kind of tricky.
This means that freezing a btrfs filesystem fails, which causes us to corrupt
with things like tux-on-ice which use the fsfreeze mechanism. So instead of
populating sb->s_bdev with a random bdev in our pool, I've broken the actual fs
freezing stuff into freeze_super and thaw_super. These just take the
super_block that we're freezing and does the appropriate work. It's basically
just copy and pasted from freeze_bdev. I've then converted freeze_bdev over to
use the new super helpers. I've tested this with ext4 and btrfs and verified
everything continues to work the same as before.
The only new gotcha is multiple calls to the fsfreeze ioctl will return EBUSY if
the fs is already frozen. I thought this was a better solution than adding a
freeze counter to the super_block, but if everybody hates this idea I'm open to
suggestions. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The patch just convert all blkdev_issue_xxx function to common
set of flags. Wait/allocation semantics preserved.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Currently, device claiming for exclusive open is done after low level
open - disk->fops->open() - has completed successfully. This means
that exclusive open attempts while a device is already exclusively
open will fail only after disk->fops->open() is called.
cdrom driver issues commands during open() which means that O_EXCL
open attempt can unintentionally inject commands to in-progress
command stream for burning thus disturbing burning process. In most
cases, this doesn't cause problems because the first command to be
issued is TUR which most devices can process in the middle of burning.
However, depending on how a device replies to TUR during burning,
cdrom driver may end up issuing further commands.
This can't be resolved trivially by moving bd_claim() before doing
actual open() because that means an open attempt which will end up
failing could interfere other legit O_EXCL open attempts.
ie. unconfirmed open attempts can fail others.
This patch resolves the problem by introducing claiming block which is
started by bd_start_claiming() and terminated either by bd_claim() or
bd_abort_claiming(). bd_claim() from inside a claiming block is
guaranteed to succeed and once a claiming block is started, other
bd_start_claiming() or bd_claim() attempts block till the current
claiming block is terminated.
bd_claim() can still be used standalone although now it always
synchronizes against claiming blocks, so the existing users will keep
working without any change.
blkdev_open() and open_bdev_exclusive() are converted to use claiming
blocks so that exclusive open attempts from these functions don't
interfere with the existing exclusive open.
This problem was discovered while investigating bko#15403.
https://bugzilla.kernel.org/show_bug.cgi?id=15403
The burning problem itself can be resolved by updating userspace
probing tools to always open w/ O_EXCL.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Matthias-Christian Ott <ott@mirix.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Factor out bd_may_claim() from bd_claim(), add comments and apply a
couple of cosmetic edits. This is to prepare for further updates to
claim path.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
We are seeing a large regression in database performance on recent
kernels. The database opens a block device with O_DIRECT|O_SYNC and a
number of threads write to different regions of the file at the same time.
A simple test case is below. I haven't defined DEVICE since getting it
wrong will destroy your data :) On an 3 disk LVM with a 64k chunk size we
see about 17MB/sec and only a few threads in IO wait:
procs -----io---- -system-- -----cpu------
r b bi bo in cs us sy id wa st
0 3 0 16170 656 2259 0 0 86 14 0
0 2 0 16704 695 2408 0 0 92 8 0
0 2 0 17308 744 2653 0 0 86 14 0
0 2 0 17933 759 2777 0 0 89 10 0
Most threads are blocking in vfs_fsync_range, which has:
mutex_lock(&mapping->host->i_mutex);
err = fop->fsync(file, dentry, datasync);
if (!ret)
ret = err;
mutex_unlock(&mapping->host->i_mutex);
commit 148f948ba8 (vfs: Introduce new
helpers for syncing after writing to O_SYNC file or IS_SYNC inode) offers
some explanation of what is going on:
Use these new helpers for syncing from generic VFS functions. This makes
O_SYNC writes to block devices acquire i_mutex for syncing. If we really
care about this, we can make block_fsync() drop the i_mutex and reacquire
it before it returns.
Thanks Jan for such a good commit message! As well as dropping i_mutex,
Christoph suggests we should remove the call to sync_blockdev():
> sync_blockdev is an overcomplicated alias for filemap_write_and_wait on
> the block device inode, which is exactly what we did just before calling
> into ->fsync
The patch below incorporates both suggestions. With it the testcase improves
from 17MB/s to 68M/sec:
procs -----io---- -system-- -----cpu------
r b bi bo in cs us sy id wa st
0 7 0 65536 1000 3878 0 0 70 30 0
0 34 0 69632 1016 3921 0 1 46 53 0
0 57 0 69632 1000 3921 0 0 55 45 0
0 53 0 69640 754 4111 0 0 81 19 0
Testcase:
#define _GNU_SOURCE
#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define NR_THREADS 64
#define BUFSIZE (64 * 1024)
#define DEVICE "/dev/mapper/XXXXXX"
#define ALIGN(VAL, SIZE) (((VAL)+(SIZE)-1) & ~((SIZE)-1))
static int fd;
static void *doit(void *arg)
{
unsigned long offset = (long)arg;
char *b, *buf;
b = malloc(BUFSIZE + 1024);
buf = (char *)ALIGN((unsigned long)b, 1024);
memset(buf, 0, BUFSIZE);
while (1)
pwrite(fd, buf, BUFSIZE, offset);
}
int main(int argc, char *argv[])
{
int flags = O_RDWR|O_DIRECT;
int i;
unsigned long offset = 0;
if (argc > 1 && !strcmp(argv[1], "O_SYNC"))
flags |= O_SYNC;
fd = open(DEVICE, flags);
if (fd == -1) {
perror("open");
exit(1);
}
for (i = 0; i < NR_THREADS-1; i++) {
pthread_t tid;
pthread_create(&tid, NULL, doit, (void *)offset);
offset += BUFSIZE;
}
doit((void *)offset);
return 0;
}
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Requested by hch, for consistency now it is exported.
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Anton Blanchard <anton@samba.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 148f948ba8 (vfs: Introduce new
helpers for syncing after writing to O_SYNC file or IS_SYNC inode) broke
the raw driver.
We now call through generic_file_aio_write -> generic_write_sync ->
vfs_fsync_range. vfs_fsync_range has:
if (!fop || !fop->fsync) {
ret = -EINVAL;
goto out;
}
But drivers/char/raw.c doesn't set an fsync method.
We have two options: fix it or remove the raw driver completely. I'm
happy to do either, the fact this has been broken for so long suggests it
is rarely used.
The patch below adds an fsync method to the raw driver. My knowledge of
the block layer is pretty sketchy so this could do with a once over.
If we instead decide to remove the raw driver, this patch might still be
useful as a backport to 2.6.33 and 2.6.32.
Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <jens.axboe@oracle.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Tested-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thanks Thomas and Christoph for testing and review.
I removed 'smp_wmb()' before up_write from the previous patch,
since up_write() should have necessary ordering constraints.
(I.e. the change of s_frozen is visible to others after up_write)
I'm quite sure the change is harmless but if you are uncomfortable
with Tested-by/Reviewed-by on the modified patch, please remove them.
If MS_RDONLY, freeze_bdev should just up_write(s_umount) instead of
deactivate_locked_super().
Also, keep sb->s_frozen consistent so that remount can check the frozen state.
Otherwise a crash reported here can happen:
http://lkml.org/lkml/2010/1/16/37http://lkml.org/lkml/2010/1/28/53
This patch should be applied for 2.6.32 stable series, too.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Backlund <tmb@mandriva.org>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently there is no barrier support in the block device code. That
means we cannot guarantee any sort of data integerity when using the
block device node with dis kwrite caches enabled. Using the raw block
device node is a typical use case for virtualization (and I assume
databases, too). This patch changes block_fsync to issue a cache flush
and thus make fsync on block device nodes actually useful.
Note that in mainline we would also need to add such code to the
->aio_write method for O_SYNC handling, but assuming that Jan's patch
series for the O_SYNC rewrite goes in it will also call into ->fsync
for 2.6.32.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
commit 0762b8bde9
(from 14 months ago) introduced a use-after-free bug which has just
recently started manifesting in my md testing.
I tried git bisect to find out what caused the bug to start
manifesting, and it could have been the recent change to
blk_unregister_queue (48c0d4d4c0) but the results were inconclusive.
This patch certainly fixes my symptoms and looks correct as the two
calls are now in the same order as elsewhere in that function.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Currently we held s_umount while a filesystem is frozen, despite that we
might return to userspace and unlock it from a different process. Instead
grab an active reference to keep the file system busy and add an explicit
check for frozen filesystems in remount and reject the remount instead
of blocking on s_umount.
Add a new get_active_super helper to super.c for use by freeze_bdev that
grabs an active reference to a superblock from a given block device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Now that we have the freeze count there is not much reason for bd_mount_sem
anymore. The actual freeze/thaw operations are serialized using the
bd_fsfreeze_mutex, and the only other place we take bd_mount_sem is
get_sb_bdev which tries to prevent mounting a filesystem while the block
device is frozen. Instead of add a check for bd_fsfreeze_count and
return -EBUSY if a filesystem is frozen. While that is a change in user
visible behaviour a failing mount is much better for this case rather
than having the mount process stuck uninterruptible for a long time.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It has been unused since it was introduced in:
commit 520808bf20e90fdbdb320264ba7dd5cf9d47dcac
Author: Andrew Morton <akpm@osdl.org>
Date: Fri May 21 00:46:17 2004 -0700
[PATCH] block device layer: separate backing_dev_info infrastructure
So lets just kill it.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
generic_file_aio_write_nolock() is now used only by block devices and raw
character device. Filesystems should use __generic_file_aio_write() in case
generic_file_aio_write() doesn't suit them. So rename the function to
blkdev_aio_write() and move it to fs/blockdev.c.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Create bdgrab(). This function copies an existing reference to a
block_device. It is safe to call from any context.
Hibernation code wishes to copy a reference to the active swap device.
Right now it calls bdget() under a spinlock, but this is wrong because
bdget() can sleep. It doesn't need a full bdget() because we already
hold a reference to active swap devices (and the spinlock protects
against swapoff).
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=13827
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Mikulas Patocka