Commit Graph

8547 Commits

Author SHA1 Message Date
Dennis Zhou 19b2a2c719 btrfs: make max async discard size tunable
Expose max_discard_size as a tunable via sysfs and switch the current
fixed maximum to the default value.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:59 +01:00
Dennis Zhou 4aa9ad5203 btrfs: limit max discard size for async discard
Throttle the maximum size of a discard so that we can provide an upper
bound for the rate of async discard. While the block layer is able to
split discards into the appropriate sized discards, we want to be able
to account more accurately the rate at which we are consuming NCQ slots
as well as limit the upper bound of work for a discard.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:59 +01:00
Dennis Zhou e93591bb6e btrfs: add kbps discard rate limit for async discard
Provide the ability to rate limit based on kbps in addition to iops as
additional guides for the target discard rate. The delay used ends up
being max(kbps_delay, iops_delay).

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:59 +01:00
Dennis Zhou a230930084 btrfs: calculate discard delay based on number of extents
An earlier patch keeps track of discardable_extents. These are
undiscarded extents managed by the free space cache. Here, we will use
this to dynamically calculate the discard delay interval.

There are 3 rate to consider. The first is the target convergence rate,
the rate to discard all discardable_extents over the
BTRFS_DISCARD_TARGET_MSEC time frame. This is clamped by the lower
limit, the iops limit or BTRFS_DISCARD_MIN_DELAY (1ms), and the upper
limit, BTRFS_DISCARD_MAX_DELAY (1s). We reevaluate this delay every
transaction commit.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:59 +01:00
Dennis Zhou 5dc7c10b87 btrfs: keep track of discardable_bytes for async discard
Keep track of this metric so that we can understand how ahead or behind
we are in discarding rate. This uses the same accounting method as
discardable_extents, deltas between previous/current values and
propagating them up.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:59 +01:00
Dennis Zhou dfb79ddb13 btrfs: track discardable extents for async discard
The number of discardable extents will serve as the rate limiting metric
for how often we should discard. This keeps track of discardable extents
in the free space caches by maintaining deltas and propagating them to
the global count.

The deltas are calculated from 2 values stored in PREV and CURR entries,
then propagated up to the global discard ctl.  The current counter value
becomes the previous counter value after update.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:58 +01:00
Dennis Zhou e4faab844a btrfs: sysfs: add UUID/debug/discard directory
Setup base sysfs directory for discard stats + tunables.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:58 +01:00
Dennis Zhou 93945cb43e btrfs: sysfs: make UUID/debug have its own kobject
Btrfs only allowed attributes to be exposed in debug/. Let's let other
groups be created by making debug its own kobject.

This also makes the per-fs debug options separate from the global
features mount attributes. This seems to be needed as
sysfs_create_files() requires const struct attribute * while
sysfs_create_group() can take struct attribute *. This seems nicer as
per file system, you'll probably use to_fs_info().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:58 +01:00
Dennis Zhou 71e8978eb4 btrfs: sysfs: add removal calls for debug/
We probably should call sysfs_remove_group() on debug/.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:58 +01:00
Dennis Zhou 2bee7eb8bb btrfs: discard one region at a time in async discard
The prior two patches added discarding via a background workqueue. This
just piggybacked off of the fstrim code to trim the whole block at once.
Well inevitably this is worse performance wise and will aggressively
overtrim. But it was nice to plumb the other infrastructure to keep the
patches easier to review.

This adds the real goal of this series which is discarding slowly (ie. a
slow long running fstrim). The discarding is split into two phases,
extents and then bitmaps. The reason for this is two fold. First, the
bitmap regions overlap the extent regions. Second, discarding the
extents first will let the newly trimmed bitmaps have the highest chance
of coalescing when being readded to the free space cache.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:58 +01:00
Dennis Zhou 6e80d4f8c4 btrfs: handle empty block_group removal for async discard
block_group removal is a little tricky. It can race with the extent
allocator, the cleaner thread, and balancing. The current path is for a
block_group to be added to the unused_bgs list. Then, when the cleaner
thread comes around, it starts a transaction and then proceeds with
removing the block_group. Extents that are pinned are subsequently
removed from the pinned trees and then eventually a discard is issued
for the entire block_group.

Async discard introduces another player into the game, the discard
workqueue. While it has none of the racing issues, the new problem is
ensuring we don't leave free space untrimmed prior to forgetting the
block_group.  This is handled by placing fully free block_groups on a
separate discard queue. This is necessary to maintain discarding order
as in the future we will slowly trim even fully free block_groups. The
ordering helps us make progress on the same block_group rather than say
the last fully freed block_group or needing to search through the fully
freed block groups at the beginning of a list and insert after.

The new order of events is a fully freed block group gets placed on the
unused discard queue first. Once it's processed, it will be placed on
the unusued_bgs list and then the original sequence of events will
happen, just without the final whole block_group discard.

The mount flags can change when processing unused_bgs, so when flipping
from DISCARD to DISCARD_ASYNC, the unused_bgs must be punted to the
discard_list to be trimmed. If we flip off DISCARD_ASYNC, we punt
free block groups on the discard_list to the unused_bg queue which will
do the final discard for us.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:57 +01:00
Dennis Zhou b0643e59cf btrfs: add the beginning of async discard, discard workqueue
When discard is enabled, everytime a pinned extent is released back to
the block_group's free space cache, a discard is issued for the extent.
This is an overeager approach when it comes to discarding and helping
the SSD maintain enough free space to prevent severe garbage collection
situations.

This adds the beginning of async discard. Instead of issuing a discard
prior to returning it to the free space, it is just marked as untrimmed.
The block_group is then added to a LRU which then feeds into a workqueue
to issue discards at a much slower rate. Full discarding of unused block
groups is still done and will be addressed in a future patch of the
series.

For now, we don't persist the discard state of extents and bitmaps.
Therefore, our failure recovery mode will be to consider extents
untrimmed. This lets us handle failure and unmounting as one in the
same.

On a number of Facebook webservers, I collected data every minute
accounting the time we spent in btrfs_finish_extent_commit() (col. 1)
and in btrfs_commit_transaction() (col. 2). btrfs_finish_extent_commit()
is where we discard extents synchronously before returning them to the
free space cache.

discard=sync:
                 p99 total per minute       p99 total per minute
      Drive   |   extent_commit() (ms)  |    commit_trans() (ms)
    ---------------------------------------------------------------
     Drive A  |           434           |          1170
     Drive B  |           880           |          2330
     Drive C  |          2943           |          3920
     Drive D  |          4763           |          5701

discard=async:
                 p99 total per minute       p99 total per minute
      Drive   |   extent_commit() (ms)  |    commit_trans() (ms)
    --------------------------------------------------------------
     Drive A  |           134           |           956
     Drive B  |            64           |          1972
     Drive C  |            59           |          1032
     Drive D  |            62           |          1200

While it's not great that the stats are cumulative over 1m, all of these
servers are running the same workload and and the delta between the two
are substantial. We are spending significantly less time in
btrfs_finish_extent_commit() which is responsible for discarding.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:57 +01:00
Dennis Zhou da080fe1ba btrfs: keep track of free space bitmap trim status cleanliness
There is a cap in btrfs in the amount of free extents that a block group
can have. When it surpasses that threshold, future extents are placed
into bitmaps. Instead of keeping track of if a certain bit is trimmed or
not in a second bitmap, keep track of the relative state of the bitmap.

With async discard, trimming bitmaps becomes a more frequent operation.
As a trade off with simplicity, we keep track of if discarding a bitmap
is in progress. If we fully scan a bitmap and trim as necessary, the
bitmap is marked clean. This has some caveats as the min block size may
skip over regions deemed too small. But this should be a reasonable
trade off rather than keeping a second bitmap and making allocation
paths more complex. The downside is we may overtrim, but ideally the min
block size should prevent us from doing that too often and getting stuck
trimming pathological cases.

BTRFS_TRIM_STATE_TRIMMING is added to indicate a bitmap is in the
process of being trimmed. If additional free space is added to that
bitmap, the bit is cleared. A bitmap will be marked
BTRFS_TRIM_STATE_TRIMMED if the trimming code was able to reach the end
of it and the former is still set.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:57 +01:00
Dennis Zhou a7ccb25585 btrfs: keep track of which extents have been discarded
Async discard will use the free space cache as backing knowledge for
which extents to discard. This patch plumbs knowledge about which
extents need to be discarded into the free space cache from
unpin_extent_range().

An untrimmed extent can merge with everything as this is a new region.
Absorbing trimmed extents is a tradeoff to for greater coalescing which
makes life better for find_free_extent(). Additionally, it seems the
size of a trim isn't as problematic as the trim io itself.

When reading in the free space cache from disk, if sync is set, mark all
extents as trimmed. The current code ensures at transaction commit that
all free space is trimmed when sync is set, so this reflects that.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:57 +01:00
Dennis Zhou 46b27f5059 btrfs: rename DISCARD mount option to to DISCARD_SYNC
This series introduces async discard which will use the flag
DISCARD_ASYNC, so rename the original flag to DISCARD_SYNC as it is
synchronously done in transaction commit.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:57 +01:00
Qu Wenruo 147a097cf0 btrfs: tree-checker: Verify location key for DIR_ITEM/DIR_INDEX
[PROBLEM]
There is a user report in the mail list, showing the following corrupted
tree blocks:

       item 62 key (486836 DIR_ITEM 2543451757) itemoff 6273 itemsize 74
               location key (4065004 INODE_ITEM 1073741824) type FILE
               transid 21397 data_len 0 name_len 44
               name: FILENAME

Note that location key, its offset should be 0 for all INODE_ITEMS.
This caused failed lookup of the inode.

[CAUSE]
That offending value, 1073741824, is 0x40000000. So this looks like a
memory bit flip.

[FIX]
This patch will enhance tree-checker to check location key of
DIR_INDEX/DIR_ITEM/XATTR_ITEM.

There are several different combinations needs to check:

- item_key.type == DIR_INDEX/DIR_ITEM

  * location_key.type == BTRFS_INODE_ITEM_KEY
    This location_key should follow the check in inode_item check.
  * location_key.type == BTRFS_ROOT_ITEM_KEY
    Despite the existing check, DIR_INDEX/DIR_ITEM can only points to
    subvolume trees.
  * All other keys are not allowed.

- item_key.type == XATTR_ITEM
  location_key should be all 0.

Reported-by: Mike Gilbert <floppymaster@gmail.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:56 +01:00
Qu Wenruo 57a0e67491 btrfs: tree-checker: Refactor root key check into separate function
ROOT_ITEM key check itself is not as simple as single line check, and
will be reused for both ROOT_ITEM and DIR_ITEM/DIR_INDEX location key
check, so refactor such check into check_root_key().

Also since we are here, fix a comment error about ROOT_ITEM offset,
which is transid of snapshot creation, not some "older kernel behavior".

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:56 +01:00
Qu Wenruo c23c77b097 btrfs: tree-checker: Refactor inode key check into seperate function
Inode key check is not as easy as several lines, and it will be called
in more than one location (INODE_ITEM check and
DIR_ITEM/DIR_INDEX/XATTR_ITEM location key check).

So here refactor such check into check_inode_key().  And add extra
checks for XATTR_ITEM.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:56 +01:00
Qu Wenruo c3053ebb0b btrfs: tree-checker: Clean up fs_info parameter from error message wrapper
The @fs_info parameter can be extracted from extent_buffer structure,
and there are already some wrappers getting rid of the @fs_info
parameter.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:56 +01:00
Qu Wenruo f6d2a5c263 btrfs: tree-checker: Check leaf chunk item size
Inspired by btrfs-progs github issue #208, where chunk item in chunk
tree has invalid num_stripes (0).

Although that can already be caught by current btrfs_check_chunk_valid(),
that function doesn't really check item size as it needs to handle chunk
item in super block sys_chunk_array().

This patch will add two extra checks for chunk items in chunk tree:

- Basic chunk item size
  If the item is smaller than btrfs_chunk (which already contains one
  stripe), exit right now as reading num_stripes may even go beyond
  eb boundary.

- Item size check against num_stripes
  If item size doesn't match with calculated chunk size, then either the
  item size or the num_stripes is corrupted. Error out anyway.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:56 +01:00
zhengbin 0ab575c5df btrfs: Remove unneeded semicolon
Fixes coccicheck warning:

fs/btrfs/print-tree.c:320:3-4: Unneeded semicolon

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:55 +01:00
Omar Sandoval 95690e58e1 btrfs: remove struct find_free_extent.ram_bytes
This hasn't been used since it was first introduced in commit
b4bd745d12 ("btrfs: Introduce find_free_extent_ctl structure for later
rework"). Passing that to btrfs_add_reserved_bytes in find_free_extent
is not strictly necessary and using the local ram_bytes instead seems
cleaner.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:55 +01:00
Omar Sandoval c8b04030c5 btrfs: simplify compressed/inline check in __extent_writepage_io()
Commit 7087a9d8db ("btrfs: Remove
extent_io_ops::writepage_end_io_hook") left this logic in a confusing
state. Simplify it.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:55 +01:00
Omar Sandoval 39b07b5d70 btrfs: drop create parameter to btrfs_get_extent()
We only pass this as 1 from __extent_writepage_io(). The parameter
basically means "pretend I didn't pass in a page". This is silly since
we can simply not pass in the page. Get rid of the parameter from
btrfs_get_extent(), and since it's used as a get_extent_t callback,
remove it from get_extent_t and btree_get_extent(), neither of which
need it.

While we're here, let's document btrfs_get_extent().

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:55 +01:00
Omar Sandoval f95d713b54 btrfs: remove redundant i_size check in __extent_writepage_io()
In __extent_writepage_io(), we check whether

  i_size <= page_offset(page).

Note that if i_size < page_offset(page), then
i_size >> PAGE_SHIFT < page->index.

If i_size == page_offset(page), then
i_size >> PAGE_SHIFT == page->index && offset_in_page(i_size) == 0.

__extent_writepage() already has a check for these cases that
returns without calling __extent_writepage_io():

  end_index = i_size >> PAGE_SHIFT
  pg_offset = offset_in_page(i_size);
  if (page->index > end_index ||
     (page->index == end_index && !pg_offset)) {
          page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
          unlock_page(page);
          return 0;
  }

Get rid of the one in __extent_writepage_io(), which was obsoleted in
211c17f51f ("Fix corners in writepage and btrfs_truncate_page").

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:55 +01:00
Omar Sandoval 169d2c875e btrfs: remove trivial goto label in __extent_writepage()
Since 40f765805f ("Btrfs: split up __extent_writepage to lower stack
usage"), done_unlocked is simply a return 0. Get rid of it.
Mid-statement block returns don seem to make the code less readable here.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:54 +01:00
Omar Sandoval eb70d22263 btrfs: remove unnecessary pg_offset assignments in __extent_writepage()
We're initializing pg_offset to 0, setting it immediately, then
reassigning it to 0 again after. The former became unnecessary in
211c17f51f ("Fix corners in writepage and btrfs_truncate_page"). The
latter is a leftover that should've been removed in 40f765805f
("Btrfs: split up __extent_writepage to lower stack usage"). Remove
both.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:54 +01:00
Omar Sandoval bffe633e00 btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_item
ordered->start, ordered->len, and ordered->disk_len correspond to
fi->disk_bytenr, fi->num_bytes, and fi->disk_num_bytes, respectively.
It's confusing to translate between the two naming schemes. Since a
btrfs_ordered_extent is basically a pending btrfs_file_extent_item,
let's make the former use the naming from the latter.

Note that I didn't touch the names in tracepoints just in case there are
scripts depending on the current naming.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:54 +01:00
Omar Sandoval 313facc5bd btrfs: remove dead snapshot-aware defrag code
Snapshot-aware defrag has been disabled since commit 8101c8dbf6
("Btrfs: disable snapshot aware defrag for now") almost 6 years ago.
Let's remove the dead code. If someone is up to the task of bringing it
back, they can dig it up from git.

This is logically a revert of commit 38c227d87c ("Btrfs:
snapshot-aware defrag") except that now we have to clear the
EXTENT_DEFRAG bit to avoid need_force_cow() returning true forever.

The reasons to disable were caused by runtime problems (like long stalls
or memory consumption) on heavily referenced extents (eg. thousands of
snapshots). There were attempts to fix that but never finished.

Current defrag breaks the extent references and some users prefer that
behaviour over the one implemented by snapshot aware (ie. keeping links
for defragmentation).  To enable both usecases we'd need to extend
defrag ioctl but let's do that properly from scratch.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ enhance ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:54 +01:00
Omar Sandoval db72e47f79 btrfs: get rid of at_offset parameter to btrfs_lookup_bio_sums()
We can encode this in the offset parameter: -1 means use the page
offsets, anything else is a valid offset.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:54 +01:00
Omar Sandoval e62958fce9 btrfs: get rid of trivial __btrfs_lookup_bio_sums() wrappers
Currently, we have two wrappers for __btrfs_lookup_bio_sums():
btrfs_lookup_bio_sums_dio(), which is used for direct I/O, and
btrfs_lookup_bio_sums(), which is used everywhere else. The only
difference is that the _dio variant looks up csums starting at the given
offset instead of using the page index, which isn't actually direct
I/O-specific. Let's clean up the signature and return value of
__btrfs_lookup_bio_sums(), rename it to btrfs_lookup_bio_sums(), and get
rid of the trivial helpers.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:53 +01:00
Johannes Thumshirn 321f69f86a btrfs: reset device back to allocation state when removing
When closing a device, btrfs_close_one_device() first allocates a new
device, copies the device to close's name, replaces it in the dev_list
with the copy and then finally frees it.

This involves two memory allocation, which can potentially fail. As this
code path is tricky to unwind, the allocation failures where handled by
BUG_ON()s.

But this copying isn't strictly needed, all that is needed is resetting
the device in question to it's state it had after the allocation.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:53 +01:00
Johannes Thumshirn 3fff3975a7 btrfs: decrement number of open devices after closing the device not before
In btrfs_close_one_device we're decrementing the number of open devices
before we're calling btrfs_close_bdev().

As there is no intermediate exit between these points in this function it
is technically OK to do so, but it makes the code a bit harder to understand.

Move both operations closer together and move the decrement step after
btrfs_close_bdev().

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:53 +01:00
Omar Sandoval 6bb6b51447 btrfs: use simple_dir_inode_operations for placeholder subvolume directory
When you snapshot a subvolume containing a subvolume, you get a
placeholder directory where the subvolume would be. These directories
have their own btrfs_dir_ro_inode_operations.

Al pointed out [1] that these directories can use simple_lookup()
instead of btrfs_lookup(), as they are always empty. Furthermore, they
can use the default generic_permission() instead of btrfs_permission();
the additional checks in the latter don't matter because we can't write
to the directory anyways. Finally, they can use the default
generic_update_time() instead of btrfs_update_time(), as the inode
doesn't exist on disk and doesn't need any special handling.

All together, this means that we can get rid of
btrfs_dir_ro_inode_operations and use simple_dir_inode_operations
instead.

1: https://lore.kernel.org/linux-btrfs/20190929052934.GY26530@ZenIV.linux.org.uk/

Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:53 +01:00
Johannes Thumshirn b38f4cbd65 btrfs: remove impossible WARN_ON in btrfs_destroy_dev_replace_tgtdev()
We have a user report, that cppcheck is complaining about a possible
NULL-pointer dereference in btrfs_destroy_dev_replace_tgtdev().

We're first dereferencing the 'tgtdev' variable and the later check for
the validity of the pointer with a WARN_ON(!tgtdev);

But all callers of btrfs_destroy_dev_replace_tgtdev() either explicitly
check if 'tgtdev' is non-NULL or directly allocate 'tgtdev', so the
WARN_ON() is impossible to hit. Just remove it to silence the checker's
complains.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205003
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:53 +01:00
Johannes Thumshirn 1296995225 btrfs: remove superfluous BUG_ON() in integrity checks
btrfsic_process_superblock() BUG_ON()s if 'state' is NULL. But this can
never happen as the only caller from btrfsic_process_superblock() is
btrfsic_mount() which allocates 'state' some lines above calling
btrfsic_process_superblock() and checks for the allocation to succeed.

Let's just remove the impossible to hit BUG_ON().

Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:52 +01:00
Johannes Thumshirn 3dbd351df4 btrfs: fix possible NULL-pointer dereference in integrity checks
A user reports a possible NULL-pointer dereference in
btrfsic_process_superblock(). We are assigning state->fs_info to a local
fs_info variable and afterwards checking for the presence of state.

While we would BUG_ON() a NULL state anyways, we can also just remove
the local fs_info copy, as fs_info is only used once as the first
argument for btrfs_num_copies(). There we can just pass in
state->fs_info as well.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205003
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:52 +01:00
Josef Bacik f893556637 btrfs: kill min_allocable_bytes in inc_block_group_ro
This is a relic from a time before we had a proper reservation mechanism
and you could end up with really full chunks at chunk allocation time.
This doesn't make sense anymore, so just kill it.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:52 +01:00
Josef Bacik 9f246926b4 btrfs: don't pass system_chunk into can_overcommit
We have the space_info, we can just check its flags to see if it's the
system chunk space info.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:52 +01:00
Nikolay Borisov 511a32b549 btrfs: Opencode ordered_data_tree_panic
It's a simple wrapper over btrfs_panic and is called only once. Just
open code it.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:52 +01:00
Qu Wenruo 430640e316 btrfs: relocation: Output current relocation stage at btrfs_relocate_block_group()
There are two relocation stages but both print the same message. Add the
description of the stage. This can help debugging or provides
informative message to users.

  BTRFS info (device dm-5): balance: start -d -m -s
  BTRFS info (device dm-5): relocating block group 30408704 flags metadata|dup
  BTRFS info (device dm-5): found 2 extents, stage: move data extents
  BTRFS info (device dm-5): relocating block group 22020096 flags system|dup
  BTRFS info (device dm-5): found 1 extents, stage: move data extents
  BTRFS info (device dm-5): relocating block group 13631488 flags data
  BTRFS info (device dm-5): found 1 extents, stage: move data extents
  BTRFS info (device dm-5): found 1 extents, stage: update data pointers
  BTRFS info (device dm-5): balance: ended with status: 0

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:51 +01:00
Yunfeng Ye 76de60ed04 btrfs: remove unused condition check in btrfs_page_mkwrite()
The condition '!ret2' is always true. commit 717beb96d9 ("Btrfs: fix
regression in btrfs_page_mkwrite() from vm_fault_t conversion") left
behind the check after moving this code out of the goto, so remove the
unused condition check.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:51 +01:00
Nikolay Borisov 36ee0b44ad btrfs: Remove redundant WARN_ON in walk_down_log_tree
level <0 and level >= BTRFS_MAX_LEVEL are already performed upon
extent buffer read by tree checker in btrfs_check_node.
go. As far as 'level <= 0'  we are guaranteed that level is '> 0'
because the value of level _before_ reading 'next' is larger than 1
(otherwise we wouldn't have executed that code at all) this in turn
guarantees that 'level' after btrfs_read_buffer is 'level - 1' since
we verify this invariant in:

    btrfs_read_buffer
     btree_read_extent_buffer_pages
      btrfs_verify_level_key

This guarantees that level can never be '<= 0' so the warn on is
never triggered.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:51 +01:00
Nikolay Borisov 5c4b691eb8 btrfs: Remove WARN_ON in walk_log_tree
The log_root passed to walk_log_tree is guaranteed to have its
root_key.objectid always be BTRFS_TREE_LOG_OBJECTID. This is by
merit that all log roots of an ordinary root are allocated in
alloc_log_tree which hard-codes objectid to be BTRFS_TREE_LOG_OBJECTID.

In case walk_log_tree is called for a log tree found by btrfs_read_fs_root
in btrfs_recover_log_trees, that function already ensures
found_key.objectid is BTRFS_TREE_LOG_OBJECTID.

No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:51 +01:00
Nikolay Borisov a0fbf736d3 btrfs: Rename __btrfs_free_reserved_extent to btrfs_pin_reserved_extent
__btrfs_free_reserved_extent now performs the actions of
btrfs_free_and_pin_reserved_extent. But this name is a bit of a
misnomer, since the extent is not really freed but just pinned. Reflect
this in the new name. No semantics changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:51 +01:00
Nikolay Borisov 7ef54d54bf btrfs: Open code __btrfs_free_reserved_extent in btrfs_free_reserved_extent
__btrfs_free_reserved_extent performs 2 entirely different operations
depending on whether its 'pin' argument is true or false. This patch
lifts the 2nd case (pin is false) into it's sole caller
btrfs_free_reserved_extent. No semantics changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:51 +01:00
Nikolay Borisov 4eaaec24c0 btrfs: Don't discard unwritten extents
All callers of btrfs_free_reserved_extent (respectively
__btrfs_free_reserved_extent with in set to 0) pass in extents which
have only been reserved but not yet written to. Namely,

* in cow_file_range that function is called only if create_io_em fails
  or btrfs_add_ordered_extent fail, both of which happen _before_ any IO
  is submitted to the newly reserved range

* in submit_compressed_extents the code flow is similar -
  out_free_reserve can be called only before
  btrfs_submit_compressed_write which is where any writes to the range
  could occur

* btrfs_new_extent_direct also calls btrfs_free_reserved_extent only
  if extent_map fails, before any IO is issued

* __btrfs_prealloc_file_range also calls btrfs_free_reserved_extent
  in case insertion of the metadata fails

* btrfs_alloc_tree_block again can only be called in case in-memory
  operations fail, before any IO is submitted

* btrfs_finish_ordered_io - this is the only caller where discarding
  the extent could have a material effect, since it can be called for
  an extent which was partially written.

With this change the submission of discards is optimised since discards
are now not being created for extents which are known to not have been
touched on disk.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:50 +01:00
Marcos Paulo de Souza 8a36e408d4 btrfs: qgroup: return ENOTCONN instead of EINVAL when quotas are not enabled
[PROBLEM]
qgroup create/remove code is currently returning EINVAL when the user
tries to create a qgroup on a subvolume without quota enabled. EINVAL is
already being used for too many error scenarios so that is hard to
depict what is the problem.

[FIX]
Currently scrub and balance code return -ENOTCONN when the user tries to
cancel/pause and no scrub or balance is currently running for the
desired subvolume. Do the same here by returning -ENOTCONN  when a user
tries to create/delete/assing/list a qgroup on a subvolume without quota
enabled.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:50 +01:00
Marcos Paulo de Souza e3b0edd297 btrfs: qgroup: remove one-time use variables for quota_root checks
Remove some variables that are set only to be checked later, and never
used.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:50 +01:00
Anand Jain bc036bb335 btrfs: sysfs, merge btrfs_sysfs_add devices_kobj and fsid
Merge btrfs_sysfs_add_fsid() and btrfs_sysfs_add_devices_kobj() functions
as these two are small and they are called one after the other.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20 16:40:50 +01:00