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18 months agobtrfs: use log root when iterating over index keys when logging directory
Filipe Manana [Wed, 5 Apr 2023 17:51:30 +0000 (18:51 +0100)]
btrfs: use log root when iterating over index keys when logging directory

When logging dir dentries of a directory, we iterate over the subvolume
tree to find dir index keys on leaves modified in the current transaction.
This however is heavy on locking, since btrfs_search_forward() may often
keep locks on extent buffers for quite a while when walking the tree to
find a suitable leaf modified in the current transaction and with a key
not smaller than then the provided minimum key. That means it will block
other tasks trying to access the subvolume tree, which may be common fs
operations like creating, renaming, linking, unlinking, reflinking files,
etc.

A better solution is to iterate the log tree, since it's much smaller than
a subvolume tree and just use plain btrfs_search_slot() (or the wrapper
btrfs_for_each_slot()) and only contains dir index keys added in the
current transaction.

The following bonnie++ test on a non-debug kernel (with Debian's default
kernel config) on a 20G null block device, was used to measure the impact:

   $ cat test.sh
   #!/bin/bash

   DEV=/dev/nullb0
   MNT=/mnt/nullb0

   NR_DIRECTORIES=20
   NR_FILES=20480  # must be a multiple of 1024
   DATASET_SIZE=$(( (8 * 1024 * 1024 * 1024) / 1048576 )) # 8 GiB as megabytes
   DIRECTORY_SIZE=$(( DATASET_SIZE / NR_FILES ))
   NR_FILES=$(( NR_FILES / 1024 ))

   umount $DEV &> /dev/null
   mkfs.btrfs -f $DEV
   mount $DEV $MNT

   bonnie++ -u root -d $MNT \
       -n $NR_FILES:$DIRECTORY_SIZE:$DIRECTORY_SIZE:$NR_DIRECTORIES \
       -r 0 -s $DATASET_SIZE -b

   umount $MNT

Before patchset:

   Version 2.00a       ------Sequential Output------ --Sequential Input- --Random-
                       -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
   Name:Size etc        /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
   debian0          8G  376k  99  1.1g  98  939m  92 1527k  99  3.2g  99  9060 256
   Latency             24920us     207us     680ms    5594us     171us    2891us
   Version 2.00a       ------Sequential Create------ --------Random Create--------
   debian0             -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
                 files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 20/20 20480  96 +++++ +++ 20480  95 20480  99 +++++ +++ 20480  97
   Latency              8708us     137us    5128us    6743us      60us   19712us

After patchset:

   Version 2.00a       ------Sequential Output------ --Sequential Input- --Random-
                       -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
   Name:Size etc        /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
   debian0          8G  384k  99  1.2g  99  971m  91 1533k  99  3.3g  99  9180 309
   Latency             24930us     125us     661ms    5587us      46us    2020us
   Version 2.00a       ------Sequential Create------ --------Random Create--------
   debian0             -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
                 files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 20/20 20480  90 +++++ +++ 20480  99 20480  99 +++++ +++ 20480  97
   Latency              7030us      61us    1246us    4942us      56us   16855us

The patchset consists of this patch plus a previous one that has the
following subject:

   "btrfs: avoid iterating over all indexes when logging directory"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: avoid iterating over all indexes when logging directory
Filipe Manana [Wed, 5 Apr 2023 17:51:29 +0000 (18:51 +0100)]
btrfs: avoid iterating over all indexes when logging directory

When logging a directory, after copying all directory index items from the
subvolume tree to the log tree, we iterate over the subvolume tree to find
all dir index items that are located in leaves COWed (or created) in the
current transaction. If we keep logging a directory several times during
the same transaction, we end up iterating over the same dir index items
everytime we log the directory, wasting time and adding extra lock
contention on the subvolume tree.

So just keep track of the last logged dir index offset in order to start
the search for that index (+1) the next time the directory is logged, as
dir index values (key offsets) come from a monotonically increasing
counter.

The following test measures the difference before and after this change:

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/nullb0
  MNT=/mnt/nullb0

  umount $DEV &> /dev/null
  mkfs.btrfs -f $DEV
  mount -o ssd $DEV $MNT

  # Time values in milliseconds.
  declare -a fsync_times
  # Total number of files added to the test directory.
  num_files=1000000
  # Fsync directory after every N files are added.
  fsync_period=100

  mkdir $MNT/testdir

  fsync_total_time=0
  for ((i = 1; i <= $num_files; i++)); do
        echo -n > $MNT/testdir/file_$i

        if [ $((i % fsync_period)) -eq 0 ]; then
                start=$(date +%s%N)
                xfs_io -c "fsync" $MNT/testdir
                end=$(date +%s%N)
                fsync_total_time=$((fsync_total_time + (end - start)))
                fsync_times[i]=$(( (end - start) / 1000000 ))
                echo -n -e "Progress $i / $num_files\r"
        fi
  done

  echo -e "\nHistogram of directory fsync duration in ms:\n"

  printf '%s\n' "${fsync_times[@]}" | \
     perl -MStatistics::Histogram -e '@d = <>; print get_histogram(\@d);'

  fsync_total_time=$((fsync_total_time / 1000000))
  echo -e "\nTotal time spent in fsync: $fsync_total_time ms\n"
  echo

  umount $MNT

The test was run on a non-debug kernel (Debian's default kernel config)
against a 15G null block device.

Result before this change:

   Histogram of directory fsync duration in ms:

   Count: 10000
   Range:  3.000 - 362.000; Mean: 34.556; Median: 31.000; Stddev: 25.751
   Percentiles:  90th: 71.000; 95th: 77.000; 99th: 81.000
      3.000 -    5.278:  1423 #################################
      5.278 -    8.854:  1173 ###########################
      8.854 -   14.467:   591 ##############
     14.467 -   23.277:  1025 #######################
     23.277 -   37.105:  1422 #################################
     37.105 -   58.809:  2036 ###############################################
     58.809 -   92.876:  2316 #####################################################
     92.876 -  146.346:     6 |
    146.346 -  230.271:     6 |
    230.271 -  362.000:     2 |

   Total time spent in fsync: 350527 ms

Result after this change:

   Histogram of directory fsync duration in ms:

   Count: 10000
   Range:  3.000 - 1088.000; Mean:  8.704; Median:  8.000; Stddev: 12.576
   Percentiles:  90th: 12.000; 95th: 14.000; 99th: 17.000
      3.000 -    6.007:  3222 #################################
      6.007 -   11.276:  5197 #####################################################
     11.276 -   20.506:  1551 ################
     20.506 -   36.674:    24 |
     36.674 -  201.552:     1 |
    201.552 -  353.841:     4 |
    353.841 - 1088.000:     1 |

   Total time spent in fsync: 92114 ms

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: dev-replace: error out if we have unrepaired metadata error during
Qu Wenruo [Thu, 6 Apr 2023 07:26:29 +0000 (15:26 +0800)]
btrfs: dev-replace: error out if we have unrepaired metadata error during

[BUG]
Even before the scrub rework, if we have some corrupted metadata failed
to be repaired during replace, we still continue replacing and let it
finish just as there is nothing wrong:

 BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started
 BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1
 BTRFS warning (device dm-4): tree block 5578752 mirror 0 has bad csum, has 0x00000000 want 0xade80ca1
 BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5
 BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5
 BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0
 BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad bytenr, has 0 want 5578752
 BTRFS error (device dm-4): unable to fixup (regular) error at logical 5578752 on dev /dev/mapper/test-scratch1
 BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 finished

This can lead to unexpected problems for the resulting filesystem.

[CAUSE]
Btrfs reuses scrub code path for dev-replace to iterate all dev extents.
But unlike scrub, dev-replace doesn't really bother to check the scrub
progress, which records all the errors found during replace.

And even if we check the progress, we cannot really determine which
errors are minor, which are critical just by the plain numbers.
(remember we don't treat metadata/data checksum error differently).

This behavior is there from the very beginning.

[FIX]
Instead of continuing the replace, just error out if we hit an
unrepaired metadata sector.

Now the dev-replace would be rejected with -EIO, to let the user know.
Although it also means, the filesystem has some metadata error which
cannot be repaired, the user would be upset anyway.

The new dmesg would look like this:

 BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started
 BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1
 BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1
 BTRFS error (device dm-4): unable to fixup (regular) error at logical 5570560 on dev /dev/mapper/test-scratch1 physical 5570560
 BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5
 BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5
 BTRFS error (device dm-4): stripe 5570560 has unrepaired metadata sector at 5578752
 BTRFS error (device dm-4): btrfs_scrub_dev(/dev/mapper/test-scratch1, 1, /dev/mapper/test-scratch2) failed -5

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove pointless loop at btrfs_get_next_valid_item()
Filipe Manana [Wed, 5 Apr 2023 17:52:23 +0000 (18:52 +0100)]
btrfs: remove pointless loop at btrfs_get_next_valid_item()

It's pointless to have a while loop at btrfs_get_next_valid_item(), as if
the slot on the current leaf is beyond the last item, we call
btrfs_next_leaf(), which leaves us at a valid slot of the next leaf (or
a valid slot in the current leaf if after releasing the path an item gets
pushed from the next leaf to the current leaf).

So just call btrfs_next_leaf() if the current slot on the current leaf is
beyond the last item.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: reject unsupported scrub flags
Qu Wenruo [Thu, 6 Apr 2023 05:00:34 +0000 (13:00 +0800)]
btrfs: scrub: reject unsupported scrub flags

Since the introduction of scrub interface, the only flag that we support
is BTRFS_SCRUB_READONLY.  Thus there is no sanity checks, if there are
some undefined flags passed in, we just ignore them.

This is problematic if we want to introduce new scrub flags, as we have
no way to determine if such flags are supported.

Address the problem by introducing a check for the flags, and if
unsupported flags are set, return -EOPNOTSUPP to inform the user space.

This check should be backported for all supported kernels before any new
scrub flags are introduced.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: reinterpret async discard iops_limit=0 as no delay
Boris Burkov [Wed, 5 Apr 2023 19:43:59 +0000 (12:43 -0700)]
btrfs: reinterpret async discard iops_limit=0 as no delay

Currently, a limit of 0 results in a hard coded metering over 6 hours.
Since the default is a set limit, I suspect no one truly depends on this
rather arbitrary setting. Repurpose it for an arguably more useful
"unlimited" mode, where the delay is 0.

Note that if block groups are too new, or go fully empty, there is still
a delay associated with those conditions. Those delays implement
heuristics for not trimming a region we are relatively likely to fully
overwrite soon.

CC: stable@vger.kernel.org # 6.2+
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: set default discard iops_limit to 1000
Boris Burkov [Wed, 5 Apr 2023 19:43:58 +0000 (12:43 -0700)]
btrfs: set default discard iops_limit to 1000

Previously, the default was a relatively conservative 10. This results
in a 100ms delay, so with ~300 discards in a commit, it takes the full
30s till the next commit to finish the discards. On a workstation, this
results in the disk never going idle, wasting power/battery, etc.

Set the default to 1000, which results in using the smallest possible
delay, currently, which is 1ms. This has shown to not pathologically
keep the disk busy by the original reporter.

Link: https://lore.kernel.org/linux-btrfs/Y%2F+n1wS%2F4XAH7X1p@nz/
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2182228
CC: stable@vger.kernel.org # 6.2+
Reviewed-by: Neal Gompa <neal@gompa.dev
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove unused raid56 functions which were dedicated for scrub
Qu Wenruo [Wed, 12 Apr 2023 06:47:50 +0000 (14:47 +0800)]
btrfs: remove unused raid56 functions which were dedicated for scrub

Since the scrub rework, the following RAID56 functions are no longer
called:

- raid56_add_scrub_pages()
- raid56_alloc_missing_rbio()
- raid56_submit_missing_rbio()

Those functions are all utilized by scrub to handle missing device cases
for RAID56.

However the new scrub code handle them in a completely different way:

- If it's data stripe, go recovery path through btrfs_submit_bio()
- If it's P/Q stripe, it would be handled through
  raid56_parity_submit_scrub_rbio()
  And that function would handle dev-replace and repair properly.

Thus we can safely remove those functions.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove scrub_bio structure
Qu Wenruo [Wed, 29 Mar 2023 06:54:57 +0000 (14:54 +0800)]
btrfs: scrub: remove scrub_bio structure

Since scrub path has been fully moved to scrub_stripe based facilities,
no more scrub_bio would be submitted.
Thus we can remove it completely, this involves:

- SCRUB_SECTORS_PER_BIO macro
- SCRUB_BIOS_PER_SCTX macro
- SCRUB_MAX_PAGES macro
- BTRFS_MAX_MIRRORS macro
- scrub_bio structure
- scrub_ctx::bios member
- scrub_ctx::curr member
- scrub_ctx::bios_in_flight member
- scrub_ctx::workers_pending member
- scrub_ctx::list_lock member
- scrub_ctx::list_wait member

- function scrub_bio_end_io_worker()
- function scrub_pending_bio_inc()
- function scrub_pending_bio_dec()
- function scrub_throttle()
- function scrub_submit()

- function scrub_find_csum()
- function drop_csum_range()

- Some unnecessary flush and scrub pauses

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove scrub_block and scrub_sector structures
Qu Wenruo [Wed, 29 Mar 2023 06:42:38 +0000 (14:42 +0800)]
btrfs: scrub: remove scrub_block and scrub_sector structures

Those two structures are used to represent a bunch of sectors for scrub,
but now they are fully replaced by scrub_stripe in one go, so we can
remove them. This involves:

- structure scrub_block
- structure scrub_sector

- structure scrub_page_private
- function attach_scrub_page_private()
- function detach_scrub_page_private()
  Now we no longer need to use page::private to handle subpage.

- function alloc_scrub_block()
- function alloc_scrub_sector()
- function scrub_sector_get_page()
- function scrub_sector_get_page_offset()
- function scrub_sector_get_kaddr()
- function bio_add_scrub_sector()

- function scrub_checksum_data()
- function scrub_checksum_tree_block()
- function scrub_checksum_super()
- function scrub_check_fsid()
- function scrub_block_get()
- function scrub_block_put()
- function scrub_sector_get()
- function scrub_sector_put()
- function scrub_bio_end_io()
- function scrub_block_complete()
- function scrub_add_sector_to_rd_bio()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove the old scrub recheck code
Qu Wenruo [Wed, 29 Mar 2023 06:25:29 +0000 (14:25 +0800)]
btrfs: scrub: remove the old scrub recheck code

The old scrub code has different entrance to verify the content, and
since we have removed the writeback path, now we can start removing the
re-check part, including:

- scrub_recover structure
- scrub_sector::recover member
- function scrub_setup_recheck_block()
- function scrub_recheck_block()
- function scrub_recheck_block_checksum()
- function scrub_repair_block_group_good_copy()
- function scrub_repair_sector_from_good_copy()
- function scrub_is_page_on_raid56()

- function full_stripe_lock()
- function search_full_stripe_lock()
- function get_full_stripe_logical()
- function insert_full_stripe_lock()
- function lock_full_stripe()
- function unlock_full_stripe()
- btrfs_block_group::full_stripe_locks_root member
- btrfs_full_stripe_locks_tree structure
  This infrastructure is to ensure RAID56 scrub is properly handling
  recovery and P/Q scrub correctly.

  This is no longer needed, before P/Q scrub we will wait for all
  the involved data stripes to be scrubbed first, and RAID56 code has
  internal lock to ensure no race in the same full stripe.

- function scrub_print_warning()
- function scrub_get_recover()
- function scrub_put_recover()
- function scrub_handle_errored_block()
- function scrub_setup_recheck_block()
- function scrub_bio_wait_endio()
- function scrub_submit_raid56_bio_wait()
- function scrub_recheck_block_on_raid56()
- function scrub_recheck_block()
- function scrub_recheck_block_checksum()
- function scrub_repair_block_from_good_copy()
- function scrub_repair_sector_from_good_copy()

And two more functions exported temporarily for later cleanup:

- alloc_scrub_sector()
- alloc_scrub_block()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove the old writeback infrastructure
Qu Wenruo [Wed, 29 Mar 2023 06:16:24 +0000 (14:16 +0800)]
btrfs: scrub: remove the old writeback infrastructure

Since the whole scrub path has been switched to scrub_stripe based
solution, the old writeback path can be removed completely, which
involves:

- scrub_ctx::wr_curr_bio member
- scrub_ctx::flush_all_writes member
- function scrub_write_block_to_dev_replace()
- function scrub_write_sector_to_dev_replace()
- function scrub_add_sector_to_wr_bio()
- function scrub_wr_submit()
- function scrub_wr_bio_end_io()
- function scrub_wr_bio_end_io_worker()

And one more function needs to be exported temporarily:

- scrub_sector_get()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove scrub_parity structure
Qu Wenruo [Wed, 29 Mar 2023 05:55:20 +0000 (13:55 +0800)]
btrfs: scrub: remove scrub_parity structure

The structure scrub_parity is used to indicate that some extents are
scrubbed for the purpose of RAID56 P/Q scrubbing.

Since the whole RAID56 P/Q scrubbing path has been replaced with new
scrub_stripe infrastructure, and we no longer need to use scrub_parity
to modify the behavior of data stripes, we can remove it completely.

This removal involves:

- scrub_parity_workers
  Now only one worker would be utilized, scrub_workers, to do the read
  and repair.
  All writeback would happen at the main scrub thread.

- scrub_block::sparity member
- scrub_parity structure
- function scrub_parity_get()
- function scrub_parity_put()
- function scrub_free_parity()

- function __scrub_mark_bitmap()
- function scrub_parity_mark_sectors_error()
- function scrub_parity_mark_sectors_data()
  These helpers are no longer needed, scrub_stripe has its bitmaps and
  we can use bitmap helpers to get the error/data status.

- scrub_parity_bio_endio()
- scrub_parity_check_and_repair()
- function scrub_sectors_for_parity()
- function scrub_extent_for_parity()
- function scrub_raid56_data_stripe_for_parity()
- function scrub_raid56_parity()
  The new code would reuse the scrub read-repair and writeback path.
  Just skip the dev-replace phase.
  And scrub_stripe infrastructure allows us to submit and wait for those
  data stripes before scrubbing P/Q, without extra infrastructure.

The following two functions are temporarily exported for later cleanup:

- scrub_find_csum()
- scrub_add_sector_to_rd_bio()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: use scrub_stripe to implement RAID56 P/Q scrub
Qu Wenruo [Tue, 28 Mar 2023 08:57:35 +0000 (16:57 +0800)]
btrfs: scrub: use scrub_stripe to implement RAID56 P/Q scrub

Implement the only missing part for scrub: RAID56 P/Q stripe scrub.

The workflow is pretty straightforward for the new function,
scrub_raid56_parity_stripe():

- Go through the regular scrub path for each data stripe

- Wait for the verification and repair to finish

- Writeback the repaired sectors to data stripes

- Make sure all stripes are properly repaired
  If we have sectors unrepaired, we cannot continue, or we could further
  corrupt the P/Q stripe.

- Submit the rbio for P/Q stripe
  The dev-replace would be handled inside
  raid56_parity_submit_scrub_rbio() path.

- Wait for the above bio to finish

Although the old code is no longer used, we still keep the declaration,
as the cleanup can be several times larger than this patch itself.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure
Qu Wenruo [Mon, 20 Mar 2023 02:12:58 +0000 (10:12 +0800)]
btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure

Switch scrub_simple_mirror() to the new scrub_stripe infrastructure.

Since scrub_simple_mirror() is the core part of scrub (only RAID56
P/Q stripes don't utilize it), we can get rid of a big chunk of code,
mostly scrub_extent(), scrub_sectors() and directly called functions.

There is a functionality change:

- Scrub speed throttle now only affects read on the scrubbing device
  Writes (for repair and replace), and reads from other mirrors won't
  be limited by the set limits.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce helper to queue a stripe for scrub
Qu Wenruo [Mon, 20 Mar 2023 02:12:57 +0000 (10:12 +0800)]
btrfs: scrub: introduce helper to queue a stripe for scrub

The new helper, queue_scrub_stripe(), would try to queue a stripe for
scrub.  If all stripes are already in use, we will submit all the
existing ones and wait for them to finish.

Currently we would queue up to 8 stripes, to enlarge the blocksize to
512KiB to improve the performance. Sectors repaired on zoned need to be
relocated instead of in-place fix.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce error reporting functionality for scrub_stripe
Qu Wenruo [Mon, 20 Mar 2023 02:12:56 +0000 (10:12 +0800)]
btrfs: scrub: introduce error reporting functionality for scrub_stripe

The new helper, scrub_stripe_report_errors(), will report the result of
the scrub to system log.

The main reporting is done by introducing a new helper,
scrub_print_common_warning(), which is mostly the same content from
scrub_print_wanring(), but without the need for a scrub_block.

Since we're reporting the errors, it's the perfect time to update the
scrub stats too.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce a writeback helper for scrub_stripe
Qu Wenruo [Mon, 20 Mar 2023 02:12:55 +0000 (10:12 +0800)]
btrfs: scrub: introduce a writeback helper for scrub_stripe

Add a new helper, scrub_write_sectors(), to submit write bios for
specified sectors to the target disk.

There are several differences compared to read path:

- Utilize btrfs_submit_scrub_write()
  Now we still rely on the @mirror_num based writeback, but the
  requirement is also a little different than regular writeback or read,
  thus we have to call btrfs_submit_scrub_write().

- We cannot write the full stripe back
  We can only write the sectors we have.  There will be two call sites
  later, one for repaired sectors, one for all utilized sectors of
  dev-replace.

  Thus the callers should specify their own write_bitmap.

This function only submit the bios, will not wait for them unless for
zoned case.

Caller must explicitly wait for the IO to finish.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce the main read repair worker for scrub_stripe
Qu Wenruo [Mon, 20 Mar 2023 02:12:54 +0000 (10:12 +0800)]
btrfs: scrub: introduce the main read repair worker for scrub_stripe

The new helper, scrub_stripe_read_repair_worker(), would handle the
read-repair part:

- Wait for the previous submitted read IO to finish

- Verify the contents of the stripe

- Go through the remaining mirrors, using as large blocksize as possible
  At this stage, we just read out all the failed sectors from each
  mirror and re-verify.
  If no more failed sector, we can exit.

- Go through all mirrors again, sector-by-sector
  This time, we read sector by sector, this is to address cases where
  one bad sector mismatches the drive's internal checksum, and cause the
  whole read range to fail.

  We put this recovery method as the last resort, as sector-by-sector
  reading is slow, and reading from other mirrors may have already fixed
  the errors.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce a helper to verify one scrub_stripe
Qu Wenruo [Mon, 20 Mar 2023 02:12:53 +0000 (10:12 +0800)]
btrfs: scrub: introduce a helper to verify one scrub_stripe

The new helper, scrub_verify_stripe(), shares the same main workflow of
the old scrub code.

The major differences are:

- How pages/page_offset is grabbed
  Everything can be grabbed from scrub_stripe easily.

- When error report happens
  Currently the helper only verifies the sectors, not really doing any
  error reporting.
  The error reporting would be done after we have done the repair.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce a helper to verify one metadata block
Qu Wenruo [Mon, 20 Mar 2023 02:12:52 +0000 (10:12 +0800)]
btrfs: scrub: introduce a helper to verify one metadata block

The new helper, scrub_verify_one_metadata(), is almost the same as
scrub_checksum_tree_block().

The difference is in how we grab the pages from other structures.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce helper to find and fill sector info for a scrub_stripe
Qu Wenruo [Mon, 20 Mar 2023 02:12:51 +0000 (10:12 +0800)]
btrfs: scrub: introduce helper to find and fill sector info for a scrub_stripe

The new helper will search the extent tree to find the first extent of a
logical range, then fill the sectors array by two loops:

- Loop 1 to fill common bits and metadata generation

- Loop 2 to fill csum data (only for data bgs)
  This loop will use the new btrfs_lookup_csums_bitmap() to fill
  the full csum buffer, and set scrub_sector_verification::csum.

With all the needed info filled by this function, later we only need to
submit and verify the stripe.

Here we temporarily export the helper to avoid warning on unused static
function.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: introduce structure for new BTRFS_STRIPE_LEN based interface
Qu Wenruo [Mon, 20 Mar 2023 02:12:50 +0000 (10:12 +0800)]
btrfs: scrub: introduce structure for new BTRFS_STRIPE_LEN based interface

This patch introduces the following structures:

- scrub_sector_verification
  Contains all the needed info to verify one sector (data or metadata).

- scrub_stripe
  Contains all needed members (mostly bitmap based) to scrub one stripe
  (with a length of BTRFS_STRIPE_LEN).

The basic idea is, we keep the existing per-device scrub behavior, but
merge all the scrub_bio/scrub_bio into one generic structure, and read
the full BTRFS_STRIPE_LEN stripe on the first try.

This means we will read some sectors which are not scrub target, but
that's fine. At dev-replace time we only writeback the utilized and good
sectors, and for read-repair we only writeback the repaired sectors.

With every read submitted in BTRFS_STRIPE_LEN, the need for complex bio
form shaping would be gone.
Although to get the same performance of the old scrub behavior, we would
need to submit the initial read for two stripes at once.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: introduce a new helper to submit write bio for repair
Qu Wenruo [Mon, 20 Mar 2023 02:12:49 +0000 (10:12 +0800)]
btrfs: introduce a new helper to submit write bio for repair

Both scrub and read-repair are utilizing a special repair writes that:

- Only writes back to a single device
  Even for read-repair on RAID56, we only update the corrupted data
  stripe itself, not triggering the full RMW path.

- Requires a valid @mirror_num
  For RAID56 case, only @mirror_num == 1 is valid.
  For non-RAID56 cases, we need @mirror_num to locate our stripe.

- No data csum generation needed

These two call sites still have some differences though:

- Read-repair goes plain bio
  It doesn't need a full btrfs_bio, and goes submit_bio_wait().

- New scrub repair would go btrfs_bio
  To simplify both read and write path.

So here this patch would:

- Introduce a common helper, btrfs_map_repair_block()
  Due to the single device nature, we can use an on-stack
  btrfs_io_stripe to pass device and its physical bytenr.

- Introduce a new interface, btrfs_submit_repair_bio(), for later scrub
  code
  This is for the incoming scrub code.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: introduce btrfs_bio::fs_info member
Qu Wenruo [Thu, 23 Mar 2023 09:01:20 +0000 (17:01 +0800)]
btrfs: introduce btrfs_bio::fs_info member

Currently we're doing a lot of work for btrfs_bio:

- Checksum verification for data read bios
- Bio splits if it crosses stripe boundary
- Read repair for data read bios

However for the incoming scrub patches, we don't want this extra
functionality at all, just plain logical + mirror -> physical mapping
ability.

Thus here we do the following changes:

- Introduce btrfs_bio::fs_info
  This is for the new scrub specific btrfs_bio, which would not populate
  btrfs_bio::inode.
  Thus we need such new member to grab a fs_info

  This new member will always be populated.

- Replace @inode argument with @fs_info for btrfs_bio_init() and its
  caller
  Since @inode is no longer a mandatory member, replace it with
  @fs_info, and let involved users populate @inode.

- Skip checksum verification and generation if @bbio->inode is NULL

- Add extra ASSERT()s
  To make sure:

  * bbio->inode is properly set for involved read repair path
  * if @file_offset is set, bbio->inode is also populated

- Grab @fs_info from @bbio directly
  We can no longer go @bbio->inode->root->fs_info, as bbio->inode can be
  NULL. This involves:

  * btrfs_simple_end_io()
  * should_async_write()
  * btrfs_wq_submit_bio()
  * btrfs_use_zone_append()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: use dedicated super block verification function to scrub one super...
Qu Wenruo [Mon, 20 Mar 2023 02:12:47 +0000 (10:12 +0800)]
btrfs: scrub: use dedicated super block verification function to scrub one super block

There is really no need to go through the super complex scrub_sectors()
to just handle super blocks.  Introduce a dedicated function to handle
super block scrubbing.

This new function will introduce a behavior change, instead of using the
complex but concurrent scrub_bio system, here we just go submit-and-wait.

There is really not much sense to care the performance of super block
scrubbing. It only has 3 super blocks at most, and they are all
scattered around the devices already.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove redundant release of btrfs_device::alloc_state
Anand Jain [Tue, 4 Apr 2023 14:55:12 +0000 (22:55 +0800)]
btrfs: remove redundant release of btrfs_device::alloc_state

Commit 321f69f86a0f ("btrfs: reset device back to allocation state when
removing") included adding extent_io_tree_release(&device->alloc_state)
to btrfs_close_one_device(), which had already been called in
btrfs_free_device().

The alloc_state tree (IO_TREE_DEVICE_ALLOC_STATE), is created in
btrfs_alloc_device() and released in btrfs_close_one_device(). Therefore,
the additional call to extent_io_tree_release(&device->alloc_state) in
btrfs_free_device() is unnecessary and can be removed.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: warn for any missed cleanup at btrfs_close_one_device
Anand Jain [Tue, 4 Apr 2023 14:55:11 +0000 (22:55 +0800)]
btrfs: warn for any missed cleanup at btrfs_close_one_device

During my recent search for the root cause of a reported bug, I realized
that it's a good idea to issue a warning for missed cleanup instead of
using debug-only assertions. Since most installations run with debug off,
missed cleanups and premature calls to close could go unnoticed. However,
these issues are serious enough to warrant reporting and fixing.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agolibcrc32c: remove crc32c_impl
Christoph Hellwig [Wed, 5 Apr 2023 05:49:05 +0000 (07:49 +0200)]
libcrc32c: remove crc32c_impl

This was only ever used by btrfs, and the usage just went away.
This effectively reverts df91f56adce1 ("libcrc32c: Add crc32c_impl
function").

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: don't print the crc32c implementation at module load time
Christoph Hellwig [Wed, 5 Apr 2023 05:49:04 +0000 (07:49 +0200)]
btrfs: don't print the crc32c implementation at module load time

Btrfs can use various different checksumming algorithms, and prints
the one used for a given file system at mount time.  Don't bother
printing the crc32c implementation at module load time, the information
is available in /sys/fs/btrfs/FSID/checksum.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: tree-log: factor out a clean_log_buffer helper
Christoph Hellwig [Mon, 3 Apr 2023 14:03:55 +0000 (16:03 +0200)]
btrfs: tree-log: factor out a clean_log_buffer helper

The tree-log code has three almost identical copies for the accounting on
an extent_buffer that doesn't need to be written any more.  The only
difference is that walk_down_log_tree passed the bytenr used to find the
buffer instead of extent_buffer.start and calculates the length using the
nodesize, while the other two callers look at the extent_buffer.len
field that must always be equivalent to the nodesize.

Factor the code into a common helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agoblock: make blkcg_punt_bio_submit optional
Christoph Hellwig [Mon, 27 Mar 2023 00:49:53 +0000 (09:49 +0900)]
block: make blkcg_punt_bio_submit optional

Guard all the code to punt bios to a per-cgroup submission helper by a
new CONFIG_BLK_CGROUP_PUNT_BIO symbol that is selected by btrfs.
This way non-btrfs kernel builds don't need to have this code.

Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agoblock: async_bio_lock does not need to be bh-safe
Christoph Hellwig [Mon, 27 Mar 2023 00:49:52 +0000 (09:49 +0900)]
block: async_bio_lock does not need to be bh-safe

async_bio_lock is only taken from bio submission and workqueue context,
both are never in bottom halves.

Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs, block: move REQ_CGROUP_PUNT to btrfs
Christoph Hellwig [Mon, 27 Mar 2023 00:49:51 +0000 (09:49 +0900)]
btrfs, block: move REQ_CGROUP_PUNT to btrfs

REQ_CGROUP_PUNT is a bit annoying as it is hard to follow and adds
a branch to the bio submission hot path.  To fix this, export
blkcg_punt_bio_submit and let btrfs call it directly.  Add a new
REQ_FS_PRIVATE flag for btrfs to indicate to it's own low-level
bio submission code that a punt to the cgroup submission helper
is required.

Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs, mm: remove the punt_to_cgroup field in struct writeback_control
Christoph Hellwig [Mon, 27 Mar 2023 00:49:50 +0000 (09:49 +0900)]
btrfs, mm: remove the punt_to_cgroup field in struct writeback_control

punt_to_cgroup is only used by extent_write_locked_range, but that
function also directly controls the bio flags for the actual submission.
Remove th punt_to_cgroup field, and just set REQ_CGROUP_PUNT directly
in extent_write_locked_range.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: also use kthread_associate_blkcg for uncompressible ranges
Christoph Hellwig [Mon, 27 Mar 2023 00:49:49 +0000 (09:49 +0900)]
btrfs: also use kthread_associate_blkcg for uncompressible ranges

submit_one_async_extent needs to use submit_one_async_extent no matter
if the range it handles ends up beeing compressed or not as the deadlock
risk due to cgroup thottling is the same.  Call kthread_associate_blkcg
earlier to cover submit_uncompressed_range case as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: don't free the async_extent in submit_uncompressed_range
Christoph Hellwig [Mon, 27 Mar 2023 00:49:48 +0000 (09:49 +0900)]
btrfs: don't free the async_extent in submit_uncompressed_range

Let submit_one_async_extent, which is the only caller of
submit_uncompressed_range handle freeing of the async_extent in one
central place.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: move kthread_associate_blkcg out of btrfs_submit_compressed_write
Christoph Hellwig [Mon, 27 Mar 2023 00:49:47 +0000 (09:49 +0900)]
btrfs: move kthread_associate_blkcg out of btrfs_submit_compressed_write

btrfs_submit_compressed_write should not have to care if it is called
from a helper thread or not.  Move the kthread_associate_blkcg handling
into submit_one_async_extent, as that is the one caller that needs it.
Also move the assignment of REQ_CGROUP_PUNT into cow_file_range_async,
as that is the routine that sets up the helper thread offload.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: correctly calculate delayed ref bytes when starting transaction
Filipe Manana [Thu, 30 Mar 2023 14:39:03 +0000 (15:39 +0100)]
btrfs: correctly calculate delayed ref bytes when starting transaction

When starting a transaction, we are assuming the number of bytes used for
each delayed ref update matches the number of bytes used for each item
update, that is the return value of:

   btrfs_calc_insert_metadata_size(fs_info, num_items)

However that is not correct when we are using the free space tree, as we
need to multiply that value by 2, since delayed ref updates need to modify
the free space tree besides the extent tree.

So fix this by using btrfs_calc_delayed_ref_bytes() to get the correct
number of bytes used for delayed ref updates.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: make btrfs_block_rsv_full() check more boolean when starting transaction
Filipe Manana [Thu, 30 Mar 2023 14:39:02 +0000 (15:39 +0100)]
btrfs: make btrfs_block_rsv_full() check more boolean when starting transaction

When starting a transaction we are comparing the result of a call to
btrfs_block_rsv_full() with 0, but the function returns a boolean. While
in practice it is not incorrect, as 0 is equivalent to false, it makes it
a bit odd and less readable. So update the check to not compare against 0
and instead use the logical not (!) operator.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: split partial dio bios before submit
Boris Burkov [Tue, 28 Mar 2023 05:19:57 +0000 (14:19 +0900)]
btrfs: split partial dio bios before submit

If an application is doing direct io to a btrfs file and experiences a
page fault reading from the write buffer, iomap will issue a partial
bio, and allow the fs to keep going. However, there was a subtle bug in
this code path in the btrfs dio iomap implementation that led to the
partial write ending up as a gap in the file's extents and to be read
back as zeros.

The sequence of events in a partial write, lightly summarized and
trimmed down for brevity is as follows:

==== WRITING TASK ====
 btrfs_direct_write
 __iomap_dio_write
 iomap_iter
 btrfs_dio_iomap_begin # create full ordered extent
 iomap_dio_bio_iter
 bio_iov_iter_get_pages # page fault; partial read
 submit_bio # partial bio
 iomap_iter
 btrfs_dio_iomap_end
 btrfs_mark_ordered_io_finished # sets BTRFS_ORDERED_IOERR;
# submit to finish_ordered_fn wq
 fault_in_iov_iter_readable # btrfs_direct_write detects partial write
 __iomap_dio_write
 iomap_iter
 btrfs_dio_iomap_begin # create second partial ordered extent
 iomap_dio_bio_iter
 bio_iov_iter_get_pages # read all of remainder
 submit_bio # partial bio with all of remainder
 iomap_iter
 btrfs_dio_iomap_end # nothing exciting to do with ordered io

==== DIO ENDIO ====
== FIRST PARTIAL BIO ==
 btrfs_dio_end_io
 btrfs_mark_ordered_io_finished # bytes_left > 0
        # don't submit to finish_ordered_fn wq
== SECOND PARTIAL BIO ==
 btrfs_dio_end_io
 btrfs_mark_ordered_io_finished # bytes_left == 0
        # submit to finish_ordered_fn wq

==== BTRFS FINISH ORDERED WQ ====
== FIRST PARTIAL BIO ==
 btrfs_finish_ordered_io # called by dio_iomap_end_io, sees
         # BTRFS_ORDERED_IOERR, just drops the
         # ordered_extent
==SECOND PARTIAL BIO==
 btrfs_finish_ordered_io # called by btrfs_dio_end_io, writes out file
         # extents, csums, etc...

The essence of the problem is that while btrfs_direct_write and iomap
properly interact to submit all the correct bios, there is insufficient
logic in the btrfs dio functions (btrfs_dio_iomap_begin,
btrfs_dio_submit_io, btrfs_dio_end_io, and btrfs_dio_iomap_end) to
ensure that every bio is at least a part of a completed ordered_extent.
And it is completing an ordered_extent that results in crucial
functionality like writing out a file extent for the range.

More specifically, btrfs_dio_end_io treats the ordered extent as
unfinished but btrfs_dio_iomap_end sets BTRFS_ORDERED_IOERR on it.
Thus, the finish io work doesn't result in file extents, csums, etc.
In the aftermath, such a file behaves as though it has a hole in it,
instead of the purportedly written data.

We considered a few options for fixing the bug:

  1. treat the partial bio as if we had truncated the file, which would
     result in properly finishing it.
  2. split the ordered extent when submitting a partial bio.
  3. cache the ordered extent across calls to __iomap_dio_rw in
     iter->private, so that we could reuse it and correctly apply
     several bios to it.

I had trouble with 1, and it felt the most like a hack, so I tried 2
and 3. Since 3 has the benefit of also not creating an extra file
extent, and avoids an ordered extent lookup during bio submission, it
felt like the best option. However, that turned out to re-introduce a
deadlock which this code discarding the ordered_extent between faults
was meant to fix in the first place. (Link to an explanation of the
deadlock below.)

Therefore, go with fix 2, which requires a bit more setup work but fixes
the corruption without introducing the deadlock, which is fundamentally
caused by the ordered extent existing when we attempt to fault in a
range that overlaps with it.

Put succinctly, what this patch does is: when we submit a dio bio, check
if it is partial against the ordered extent stored in dio_data, and if it
is, extract the ordered_extent that matches the bio exactly out of the
larger ordered_extent. Keep the remaining ordered_extent around in dio_data
for cancellation in iomap_end.

Thanks to Josef, Christoph, and Filipe with their help figuring out the
bug and the fix.

Fixes: 51bd9563b678 ("btrfs: fix deadlock due to page faults during direct IO reads and writes")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2169947
Link: https://lore.kernel.org/linux-btrfs/aa1fb69e-b613-47aa-a99e-a0a2c9ed273f@app.fastmail.com/
Link: https://pastebin.com/3SDaH8C6
Link: https://lore.kernel.org/linux-btrfs/20230315195231.GW10580@twin.jikos.cz/T/#t
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
[ hch: refactored the ordered_extent extraction ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: don't split NOCOW extent_maps in btrfs_extract_ordered_extent
Boris Burkov [Tue, 28 Mar 2023 05:19:56 +0000 (14:19 +0900)]
btrfs: don't split NOCOW extent_maps in btrfs_extract_ordered_extent

NOCOW writes just overwrite an existing extent map, which thus should
not be split in btrfs_extract_ordered_extent.  The NOCOW case can't
currently happen as btrfs_extract_ordered_extent is only used on zoned
devices that do not support NOCOW writes, but this will change soon.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
[ hch: split from a larger patch, wrote a commit log ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: pass an ordered_extent to btrfs_extract_ordered_extent
Christoph Hellwig [Tue, 28 Mar 2023 05:19:55 +0000 (14:19 +0900)]
btrfs: pass an ordered_extent to btrfs_extract_ordered_extent

To prepare for a new caller that already has the ordered_extent
available, change btrfs_extract_ordered_extent to take an argument
for it.  Add a wrapper for the bio case that still has to do the
lookup (for now).

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify extent map splitting and rename split_zoned_em
Christoph Hellwig [Tue, 28 Mar 2023 05:19:54 +0000 (14:19 +0900)]
btrfs: simplify extent map splitting and rename split_zoned_em

split_zoned_em is only ever asked to split out the beginning of an extent
map.  Change it to only take a len to split out instead of a pre and post
region.

Also rename the function to split_extent_map as there is nothing zoned
device specific about it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: fold btrfs_clone_ordered_extent into btrfs_split_ordered_extent
Christoph Hellwig [Tue, 28 Mar 2023 05:19:53 +0000 (14:19 +0900)]
btrfs: fold btrfs_clone_ordered_extent into btrfs_split_ordered_extent

The function btrfs_clone_ordered_extent is very specific to the usage in
btrfs_split_ordered_extent.  Now that only a single call to
btrfs_clone_ordered_extent is left, just fold it into
btrfs_split_ordered_extent to make the operation more clear.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: sink parameter len to btrfs_split_ordered_extent
Christoph Hellwig [Tue, 28 Mar 2023 05:19:52 +0000 (14:19 +0900)]
btrfs: sink parameter len to btrfs_split_ordered_extent

btrfs_split_ordered_extent is only ever asked to split out the beginning
of an ordered_extent (i.e. post == 0).  Change it to only take a len to
split out, and switch it to allocate the new extent for the beginning,
as that helps with callers that want to keep a pointer to the
ordered_extent that it is stealing from.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify splitting logic in btrfs_extract_ordered_extent
Christoph Hellwig [Tue, 28 Mar 2023 05:19:51 +0000 (14:19 +0900)]
btrfs: simplify splitting logic in btrfs_extract_ordered_extent

btrfs_extract_ordered_extent is always used to split an ordered_extent
and extent_map into two parts, so it doesn't need to deal with a three
way split.

Simplify it by only allowing for a single split point, and always split
out the beginning of the extent, as that is what we'll later need to
be able to hold on to a reference to the original ordered_extent that
the first part is split off for submission.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: move ordered_extent internal sanity checks into btrfs_split_ordered_extent
Christoph Hellwig [Tue, 28 Mar 2023 05:19:50 +0000 (14:19 +0900)]
btrfs: move ordered_extent internal sanity checks into btrfs_split_ordered_extent

Move the three checks that are about ordered extent internal sanity
checking into btrfs_split_ordered_extent instead of doing them in the
higher level btrfs_extract_ordered_extent routine.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: stash ordered extent in dio_data during iomap dio
Boris Burkov [Tue, 28 Mar 2023 05:19:49 +0000 (14:19 +0900)]
btrfs: stash ordered extent in dio_data during iomap dio

While it is not feasible for an ordered extent to survive across the
calls btrfs_direct_write makes into __iomap_dio_rw, it is still helpful
to stash it on the dio_data in between creating it in iomap_begin and
finishing it in either end_io or iomap_end.

The specific use I have in mind is that we can check if a particular bio
is partial in submit_io without unconditionally looking up the ordered
extent. This is a preparatory patch for a later patch which does just
that.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: pass flags as unsigned long to btrfs_add_ordered_extent
Boris Burkov [Tue, 28 Mar 2023 05:19:48 +0000 (14:19 +0900)]
btrfs: pass flags as unsigned long to btrfs_add_ordered_extent

The ordered_extent flags are declared as unsigned long, so pass them as
such to btrfs_add_ordered_extent.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
[ hch: split from a larger patch ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: add function to create and return an ordered extent
Boris Burkov [Tue, 28 Mar 2023 05:19:47 +0000 (14:19 +0900)]
btrfs: add function to create and return an ordered extent

Currently, btrfs_add_ordered_extent allocates a new ordered extent, adds
it to the rb_tree, but doesn't return a referenced pointer to the
caller. There are cases where it is useful for the creator of a new
ordered_extent to hang on to such a pointer, so add a new function
btrfs_alloc_ordered_extent which is the same as
btrfs_add_ordered_extent, except it takes an additional reference count
and returns a pointer to the ordered_extent. Implement
btrfs_add_ordered_extent as btrfs_alloc_ordered_extent followed by
dropping the new reference and handling the IS_ERR case.

The type of flags in btrfs_alloc_ordered_extent and
btrfs_add_ordered_extent is changed from unsigned int to unsigned long
so it's unified with the other ordered extent functions.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: use __bio_add_page to add single a page in rbio_add_io_sector
Johannes Thumshirn [Thu, 30 Mar 2023 10:43:51 +0000 (03:43 -0700)]
btrfs: use __bio_add_page to add single a page in rbio_add_io_sector

The btrfs raid56 sector submission code uses bio_add_page() to add a
page to a newly created bio. bio_add_page() can fail, but the return
value is never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: use __bio_add_page for adding a single page in repair_one_sector
Johannes Thumshirn [Thu, 30 Mar 2023 10:43:50 +0000 (03:43 -0700)]
btrfs: use __bio_add_page for adding a single page in repair_one_sector

The btrfs repair bio submission code uses bio_add_page() to add a page
to a newly created bio. bio_add_page() can fail, but the return value is
never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: use test_and_clear_bit() in wait_dev_flush()
Anand Jain [Mon, 27 Mar 2023 09:53:10 +0000 (17:53 +0800)]
btrfs: use test_and_clear_bit() in wait_dev_flush()

The function wait_dev_flush() tests for the BTRFS_DEV_STATE_FLUSH_SENT
bit and then clears it separately. Instead, use test_and_clear_bit().
Though we don't need to do the atomic test and clear, it's following a
common pattern.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: change wait_dev_flush() return type to bool
Anand Jain [Mon, 27 Mar 2023 09:53:09 +0000 (17:53 +0800)]
btrfs: change wait_dev_flush() return type to bool

The flush error code is maintained in btrfs_device::last_flush_error, so
there is no point in returning it in wait_dev_flush() when it is not being
used. Instead, we can return a boolean value.

Note that even though btrfs_device::last_flush_error may not be used, we
will keep it for now.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: open code check_barrier_error()
Anand Jain [Mon, 27 Mar 2023 09:53:08 +0000 (17:53 +0800)]
btrfs: open code check_barrier_error()

check_barrier_error() is almost a single line function, and just calls
btrfs_check_rw_degradable(). Instead, open code it.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: move last_flush_error to write_dev_flush and wait_dev_flush
Anand Jain [Mon, 27 Mar 2023 09:53:07 +0000 (17:53 +0800)]
btrfs: move last_flush_error to write_dev_flush and wait_dev_flush

We parallelize the flush command across devices using our own code,
write_dev_flush() sends the flush command to each device and
wait_dev_flush() waits for the flush to complete on all devices. Errors
from each device are recorded at device->last_flush_error and reset to
BLK_STS_OK in write_dev_flush() and to the error, if any, in
wait_dev_flush(). These functions are called from barrier_all_devices().

This patch consolidates the use of device->last_flush_error in
write_dev_flush() and wait_dev_flush() to remove it from
barrier_all_devices().

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify exit paths of btrfs_evict_inode()
Filipe Manana [Tue, 21 Mar 2023 11:14:00 +0000 (11:14 +0000)]
btrfs: simplify exit paths of btrfs_evict_inode()

Instead of using two labels at btrfs_evict_inode() for exiting depending
on whether we need to delete the inode items and orphan or some error
happened, we can use a single exit label if we initialize the block
reserve to NULL, since btrfs_free_block_rsv() ignores a NULL block reserve
pointer. So just do that. It will also make an upcoming change simpler by
avoiding one extra error label.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: calculate the right space for delayed refs when updating global reserve
Filipe Manana [Tue, 21 Mar 2023 11:13:59 +0000 (11:13 +0000)]
btrfs: calculate the right space for delayed refs when updating global reserve

When updating the global block reserve, we account for the 6 items needed
by an unlink operation and the 6 delayed references for each one of those
items. However the calculation for the delayed references is not correct
in case we have the free space tree enabled, as in that case we need to
touch the free space tree as well and therefore need twice the number of
bytes. So use the btrfs_calc_delayed_ref_bytes() helper to calculate the
number of bytes need for the delayed references at
btrfs_update_global_block_rsv().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: use a constant for the number of metadata units needed for an unlink
Filipe Manana [Tue, 21 Mar 2023 11:13:58 +0000 (11:13 +0000)]
btrfs: use a constant for the number of metadata units needed for an unlink

Instead of hard coding the number of metadata units for an unlink operation
in a couple places, define a macro and use it instead. This eliminates the
problem of one place getting out of sync with the other, such as recently
fixed by the previous patch in the series ("btrfs: fix calculation of the
global block reserve's size").

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: fix calculation of the global block reserve's size
Filipe Manana [Tue, 21 Mar 2023 11:13:57 +0000 (11:13 +0000)]
btrfs: fix calculation of the global block reserve's size

At btrfs_update_global_block_rsv(), we are assuming an unlink operation
uses 5 metadata units, but that's not true anymore, it uses 6 since the
commit bca4ad7c0b54 ("btrfs: reserve correct number of items for unlink
and rmdir"). So update the code and comments to consider 6 units.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: calculate correct amount of space for delayed reference when evicting
Filipe Manana [Tue, 21 Mar 2023 11:13:56 +0000 (11:13 +0000)]
btrfs: calculate correct amount of space for delayed reference when evicting

When evicting an inode, we are incorrectly calculating the amount of space
required for a single delayed reference in case the free space tree is
enabled. We have to multiply by 2 the result of
btrfs_calc_insert_metadata_size(). We should be calculating according to
the size update and space release of the delayed block reserve logic at
btrfs_update_delayed_refs_rsv() and btrfs_delayed_refs_rsv_release().

Fix this by using the btrfs_calc_delayed_ref_bytes() helper at
evict_refill_and_join() instead of btrfs_calc_insert_metadata_size().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: add helper to calculate space for delayed references
Filipe Manana [Tue, 21 Mar 2023 11:13:55 +0000 (11:13 +0000)]
btrfs: add helper to calculate space for delayed references

Instead of duplicating the logic for calculating how much space is
required for a given number of delayed references, add an inline helper
to encapsulate that logic and use it everywhere we are calculating the
space required.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: constify fs_info argument for the reclaim items calculation helpers
Filipe Manana [Tue, 21 Mar 2023 11:13:54 +0000 (11:13 +0000)]
btrfs: constify fs_info argument for the reclaim items calculation helpers

Now that btrfs_calc_insert_metadata_size() can take a const fs_info
argument, make the fs_info argument of calc_reclaim_items_nr() and of
calc_delayed_refs_nr() const as well.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: constify fs_info argument of the metadata size calculation helpers
Filipe Manana [Tue, 21 Mar 2023 11:13:53 +0000 (11:13 +0000)]
btrfs: constify fs_info argument of the metadata size calculation helpers

The fs_info argument of the helpers btrfs_calc_insert_metadata_size() and
btrfs_calc_metadata_size() is not modified so it can be const. This will
also allow a new helper function in one of the next patches to have its
fs_info argument as const.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: accurately calculate number of delayed refs when flushing
Filipe Manana [Tue, 21 Mar 2023 11:13:52 +0000 (11:13 +0000)]
btrfs: accurately calculate number of delayed refs when flushing

When flushing a limited number of delayed references (FLUSH_DELAYED_REFS_NR
state), we are assuming each delayed reference is holding a number of bytes
matching the needed space for inserting for a single metadata item (the
result of btrfs_calc_insert_metadata_size()). That is not correct when
using the free space tree, as in that case we have to multiply that value
by 2 since we need to touch the free space tree as well. This is the same
computation as we do at btrfs_update_delayed_refs_rsv() and at
btrfs_delayed_refs_rsv_release().

So correct the computation for the amount of delayed references we need to
flush in case we have the free space tree. This does not fix a functional
issue, instead it makes the flush code flush less delayed references, only
the minimum necessary to satisfy a ticket.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: calculate the right space for a single delayed ref when refilling
Filipe Manana [Tue, 21 Mar 2023 11:13:51 +0000 (11:13 +0000)]
btrfs: calculate the right space for a single delayed ref when refilling

When refilling the delayed block reserve we are incorrectly computing the
amount of bytes for a single delayed reference if the free space tree is
being used. In that case we should double the calculated amount.
Everywhere else we compute the correct amount, like when updating the
delayed block reserve, at btrfs_update_delayed_refs_rsv(), or when
releasing space from the delayed block reserve, at
btrfs_delayed_refs_rsv_release().

So fix btrfs_delayed_refs_rsv_refill() to multiply the amount of bytes for
a single delayed reference by two in case the free space tree is used.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: don't throttle on delayed items when evicting deleted inode
Filipe Manana [Tue, 21 Mar 2023 11:13:50 +0000 (11:13 +0000)]
btrfs: don't throttle on delayed items when evicting deleted inode

During inode eviction, if we are truncating a deleted inode, we don't add
delayed items for our inode, so there's no need to throttle on delayed
items on each iteration of the loop that truncates inode items from its
subvolume tree. But we dirty extent buffers from its subvolume tree, so
we only need to throttle on btree inode dirty pages.

So use btrfs_btree_balance_dirty_nodelay() in the loop that truncates
inode items.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove obsolete delayed ref throttling logic when truncating items
Filipe Manana [Tue, 21 Mar 2023 11:13:49 +0000 (11:13 +0000)]
btrfs: remove obsolete delayed ref throttling logic when truncating items

We have this logic encapsulated in btrfs_should_throttle_delayed_refs()
where we try to estimate if running the current amount of delayed
references we have will take more than half a second, and if so, the
caller btrfs_should_throttle_delayed_refs() should do something to
prevent more and more delayed refs from being accumulated.

This logic was added in commit 0a2b2a844af6 ("Btrfs: throttle delayed
refs better") and then further refined in commit a79b7d4b3e81 ("Btrfs:
async delayed refs"). The idea back then was that the caller of
btrfs_should_throttle_delayed_refs() would release its transaction
handle (by calling btrfs_end_transaction()) when that function returned
true, then btrfs_end_transaction() would trigger an async job to run
delayed references in a workqueue, and later start/join a transaction
again and do more work.

However we don't run delayed references asynchronously anymore, that
was removed in commit db2462a6ad3d ("btrfs: don't run delayed refs in
the end transaction logic"). That makes the logic that tries to estimate
how long we will take to run our current delayed references, at
btrfs_should_throttle_delayed_refs(), pointless as we don't take any
action to run delayed references anymore. We do have other type of
throttling, which consists of checking the size and reserved space of
the delayed and global block reserves, as well as if fluhsing delayed
references for the current transaction was already started, etc - this
is all done by btrfs_should_end_transaction(), and the only user of
btrfs_should_throttle_delayed_refs() does periodically call
btrfs_should_end_transaction().

So remove btrfs_should_throttle_delayed_refs() and the infrastructure
that keeps track of the average time used for running delayed references,
as well as adapting btrfs_truncate_inode_items() to call
btrfs_check_space_for_delayed_refs() instead.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify variables in btrfs_block_rsv_refill()
Filipe Manana [Tue, 21 Mar 2023 11:13:48 +0000 (11:13 +0000)]
btrfs: simplify variables in btrfs_block_rsv_refill()

At btrfs_block_rsv_refill(), there's no point in initializing the
'num_bytes' variable to 0 and then, after taking the block reserve's
spinlock, initializing it to the value of the 'min_reserved' parameter.

So just get rid of the 'num_bytes' local variable and rename the
'min_reserved' parameter to 'num_bytes'.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove redundant counter check at btrfs_truncate_inode_items()
Filipe Manana [Tue, 21 Mar 2023 11:13:47 +0000 (11:13 +0000)]
btrfs: remove redundant counter check at btrfs_truncate_inode_items()

At btrfs_truncate_inode_items(), in the while loop when we decide that we
are going to delete an item, it's pointless to check that 'pending_del_nr'
is non-zero in an else clause because the corresponding if statement is
checking if 'pending_del_nr' has a value of zero. So just remove that
condition from the else clause.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: count extents before taking inode's spinlock when reserving metadata
Filipe Manana [Tue, 21 Mar 2023 11:13:46 +0000 (11:13 +0000)]
btrfs: count extents before taking inode's spinlock when reserving metadata

When reserving metadata space for delalloc (and direct IO too), at
btrfs_delalloc_reserve_metadata(), there's no need to count the number of
extents while holding the inode's spinlock, since that does not require
access to any field of the inode.

This section of code can be called concurrently, when we have direct IO
writes against different file ranges that don't increase the inode's
i_size, so it's beneficial to shorten the critical section by counting
the number of extents before taking the inode's spinlock.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove bytes_used argument from btrfs_make_block_group()
Filipe Manana [Tue, 21 Mar 2023 11:13:45 +0000 (11:13 +0000)]
btrfs: remove bytes_used argument from btrfs_make_block_group()

The only caller of btrfs_make_block_group() always passes 0 as the value
for the bytes_used argument, so remove it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: collapse should_end_transaction() into btrfs_should_end_transaction()
Filipe Manana [Tue, 21 Mar 2023 11:13:44 +0000 (11:13 +0000)]
btrfs: collapse should_end_transaction() into btrfs_should_end_transaction()

The function should_end_transaction() is very short and only has one
caller, which is btrfs_should_end_transaction(). So move the code from
should_end_transaction() into btrfs_should_end_transaction().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify btrfs_should_throttle_delayed_refs()
Filipe Manana [Tue, 21 Mar 2023 11:13:43 +0000 (11:13 +0000)]
btrfs: simplify btrfs_should_throttle_delayed_refs()

Currently btrfs_should_throttle_delayed_refs() returns 1 or 2 in case the
delayed refs should be throttled, however the only caller (inode eviction
and truncation path) does not care about those two different conditions,
it treats the return value as a boolean. This allows us to remove one of
the conditions in btrfs_should_throttle_delayed_refs() and change its
return value from 'int' to 'bool'. So just do that.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: initialize ret to -ENOSPC at __reserve_bytes()
Filipe Manana [Tue, 21 Mar 2023 11:13:42 +0000 (11:13 +0000)]
btrfs: initialize ret to -ENOSPC at __reserve_bytes()

At space-info.c:__reserve_bytes(), instead of initializing 'ret' to 0 when
it's declared and then shortly after set it to -ENOSPC under the space
info's spinlock, initialize it to -ENOSPC when declaring it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: update flush method assertion when reserving space
Filipe Manana [Tue, 21 Mar 2023 11:13:41 +0000 (11:13 +0000)]
btrfs: update flush method assertion when reserving space

When reserving space, at space-info.c:__reserve_bytes(), we assert that
either the current task is not holding a transacion handle, or, if it is,
that the flush method is not BTRFS_RESERVE_FLUSH_ALL. This is because that
flush method can trigger transaction commits, and therefore could lead to
a deadlock.

However there are other 2 flush methods that can trigger transaction
commits:

1) BTRFS_RESERVE_FLUSH_ALL_STEAL
2) BTRFS_RESERVE_FLUSH_EVICT

So update the assertion to check the flush method is also not one those
two methods if the current task is holding a transaction handle.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: update documentation for BTRFS_RESERVE_FLUSH_EVICT flush method
Filipe Manana [Tue, 21 Mar 2023 11:13:40 +0000 (11:13 +0000)]
btrfs: update documentation for BTRFS_RESERVE_FLUSH_EVICT flush method

The BTRFS_RESERVE_FLUSH_EVICT flush method can also commit transactions,
see the definition of the evict_flush_states const array at space-info.c,
but the documentation for it at space-info.h does not mention it.
So update the documentation.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove check for NULL block reserve at btrfs_block_rsv_check()
Filipe Manana [Tue, 21 Mar 2023 11:13:39 +0000 (11:13 +0000)]
btrfs: remove check for NULL block reserve at btrfs_block_rsv_check()

The block reserve passed to btrfs_block_rsv_check() is never NULL, so
remove the check. In case it can ever become NULL in the future, then
we'll get a pretty obvious and clear NULL pointer dereference crash and
stack trace.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: pass a bool size update argument to btrfs_block_rsv_add_bytes()
Filipe Manana [Tue, 21 Mar 2023 11:13:38 +0000 (11:13 +0000)]
btrfs: pass a bool size update argument to btrfs_block_rsv_add_bytes()

At btrfs_delayed_refs_rsv_refill(), we are passing a value of 0 to the
'update_size' argument of btrfs_block_rsv_add_bytes(), which is defined
as a boolean. Functionally this is fine because a 0 is, implicitly,
converted to a boolean false value. However it's easier to read an
explicit 'false' value, so just pass 'false' instead of 0.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: pass a bool to btrfs_block_rsv_migrate() at evict_refill_and_join()
Filipe Manana [Tue, 21 Mar 2023 11:13:37 +0000 (11:13 +0000)]
btrfs: pass a bool to btrfs_block_rsv_migrate() at evict_refill_and_join()

The last argument of btrfs_block_rsv_migrate() is a boolean, but we are
passing an integer, with a value of 1, to it at evict_refill_and_join().
While this is not a bug, due to type conversion, it's a lot more clear to
simply pass the boolean true value instead. So just do that.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove btrfs_lru_cache_is_full() inline function
Filipe Manana [Tue, 21 Mar 2023 11:37:04 +0000 (11:37 +0000)]
btrfs: remove btrfs_lru_cache_is_full() inline function

It's not used anywhere at the moment, but it was used in earlier version
of a patch that removed its use in the second version. So just remove
btrfs_lru_cache_is_full().

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify adding pages in btrfs_add_compressed_bio_pages
Christoph Hellwig [Tue, 14 Mar 2023 16:51:10 +0000 (17:51 +0100)]
btrfs: simplify adding pages in btrfs_add_compressed_bio_pages

btrfs_add_compressed_bio_pages is needlessly complicated.  Instead
of iterating over the logic disk offset just to add pages to the bio
use a simple offset starting at 0, which also removes most of the
claiming.  Additionally __bio_add_pages already takes care of the
assert that the bio is always properly sized, and btrfs_submit_bio
called right after asserts that the bio size is non-zero.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: move the bi_sector assignment out of btrfs_add_compressed_bio_pages
Christoph Hellwig [Tue, 14 Mar 2023 16:51:09 +0000 (17:51 +0100)]
btrfs: move the bi_sector assignment out of btrfs_add_compressed_bio_pages

Adding pages to a bio has nothing to do with the sector.  Move the
assignment to the two callers in preparation for cleaning up
btrfs_add_compressed_bio_pages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: sysfs: relax bg_reclaim_threshold for debugging purposes
Naohiro Aota [Mon, 13 Mar 2023 07:46:54 +0000 (16:46 +0900)]
btrfs: sysfs: relax bg_reclaim_threshold for debugging purposes

Currently, /sys/fs/btrfs/<UUID>/bg_reclaim_threshold is limited to 0
(disable) or [50 .. 100]%, so we need to fill 50% of a device to start the
auto reclaim process. It is cumbersome to do so when we want to shake out
possible race issues of normal write vs reclaim.

Relax the threshold check under the BTRFS_DEBUG option.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: make btrfs_split_bio work on struct btrfs_bio
Christoph Hellwig [Tue, 7 Mar 2023 16:39:45 +0000 (17:39 +0100)]
btrfs: make btrfs_split_bio work on struct btrfs_bio

btrfs_split_bio expects a btrfs_bio as argument and always allocates one.
Type both the orig_bio argument and the return value as struct btrfs_bio
to improve type safety.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: return a btrfs_bio from btrfs_bio_alloc
Christoph Hellwig [Tue, 7 Mar 2023 16:39:44 +0000 (17:39 +0100)]
btrfs: return a btrfs_bio from btrfs_bio_alloc

Return the containing struct btrfs_bio instead of the less type safe
struct bio from btrfs_bio_alloc.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: store a pointer to a btrfs_bio in struct btrfs_bio_ctrl
Christoph Hellwig [Tue, 7 Mar 2023 16:39:43 +0000 (17:39 +0100)]
btrfs: store a pointer to a btrfs_bio in struct btrfs_bio_ctrl

The bio in struct btrfs_bio_ctrl must be a btrfs_bio, so store a pointer
to the btrfs_bio for better type checking.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: simplify finding the inode in submit_one_bio
Christoph Hellwig [Tue, 7 Mar 2023 16:39:42 +0000 (17:39 +0100)]
btrfs: simplify finding the inode in submit_one_bio

struct btrfs_bio now has an always valid inode pointer that can be used
to find the inode in submit_one_bio, so use that and initialize all
variables for which it is possible at declaration time.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: store a pointer to the original btrfs_bio in struct compressed_bio
Christoph Hellwig [Tue, 7 Mar 2023 16:39:41 +0000 (17:39 +0100)]
btrfs: store a pointer to the original btrfs_bio in struct compressed_bio

The original bio must be a btrfs_bio, so store a pointer to the
btrfs_bio for better type checking.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: pass a btrfs_bio to btrfs_submit_compressed_read
Christoph Hellwig [Tue, 7 Mar 2023 16:39:40 +0000 (17:39 +0100)]
btrfs: pass a btrfs_bio to btrfs_submit_compressed_read

btrfs_submit_compressed_read expects the bio passed to it to be embedded
into a btrfs_bio structure.  Pass the btrfs_bio directly to increase type
safety and make the code self-documenting.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: pass a btrfs_bio to btrfs_submit_bio
Christoph Hellwig [Tue, 7 Mar 2023 16:39:39 +0000 (17:39 +0100)]
btrfs: pass a btrfs_bio to btrfs_submit_bio

btrfs_submit_bio expects the bio passed to it to be embedded into a
btrfs_bio structure.  Pass the btrfs_bio directly to increase type
safety and make the code self-documenting.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: move zero filling of compressed read bios into common code
Christoph Hellwig [Tue, 7 Mar 2023 16:39:38 +0000 (17:39 +0100)]
btrfs: move zero filling of compressed read bios into common code

All algorithms have to fill the remainder of the orig_bio with zeroes,
so do it in common code.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: cleanup main loop in btrfs_encoded_read_regular_fill_pages
Christoph Hellwig [Tue, 7 Mar 2023 16:39:37 +0000 (17:39 +0100)]
btrfs: cleanup main loop in btrfs_encoded_read_regular_fill_pages

btrfs_encoded_read_regular_fill_pages has a pretty odd control flow.
Unwind it so that there is a single loop over the pages array.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove unused members from struct btrfs_encoded_read_private
Christoph Hellwig [Tue, 7 Mar 2023 16:39:36 +0000 (17:39 +0100)]
btrfs: remove unused members from struct btrfs_encoded_read_private

The inode and file_offset members in struct btrfs_encoded_read_private
are unused, so remove them.

Last used in commit 7959bd441176 ("btrfs: remove the start argument to
check_data_csum and export") and commit 7609afac6775 ("btrfs: handle
checksum validation and repair at the storage layer").

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: locking: use atomic for DREW lock writers
David Sterba [Wed, 1 Mar 2023 20:47:08 +0000 (21:47 +0100)]
btrfs: locking: use atomic for DREW lock writers

The DREW lock uses percpu variable to track lock counters and for that
it needs to allocate the structure. In btrfs_read_tree_root() or
btrfs_init_fs_root() this may add another error case or requires the
NOFS scope protection.

One way is to preallocate the structure as was suggested in
https://lore.kernel.org/linux-btrfs/20221214021125.28289-1-robbieko@synology.com/

We may avoid the allocation altogether if we don't use the percpu
variables but an atomic for the writer counter. This should not make any
difference, the DREW lock is used for truncate and NOCOW writes along
with other IO operations.

The percpu counter for writers has been there since the original commit
8257b2dc3c1a1057 "Btrfs: introduce btrfs_{start, end}_nocow_write() for
each subvolume". The reason could be to avoid hammering the same
cacheline from all the readers but then the writers do that anyway.

Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: remove redundant clearing of NODISCARD
Anand Jain [Thu, 2 Mar 2023 13:30:48 +0000 (21:30 +0800)]
btrfs: remove redundant clearing of NODISCARD

If no discard mount option is specified, including the NODISCARD option,
we make the async discard the default option then we don't have to call
the clear_opt again to clear the NODISCARD flag. Though this makes no
difference, that the call is redundant has been pointed out several
times so we better remove it.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: avoid repetitive define BTRFS_FEATURE_INCOMPAT_SUPP
Anand Jain [Mon, 6 Mar 2023 13:28:09 +0000 (21:28 +0800)]
btrfs: avoid repetitive define BTRFS_FEATURE_INCOMPAT_SUPP

BTRFS_FEATURE_INCOMPAT_SUPP is defined twice, once under
CONFIG_BTRFS_DEBUG and once without it, resulting in repetitive code. The
reason for this is to add experimental features under CONFIG_BTRFS_DEBUG.

To avoid repetitive code, add a common list BTRFS_FEATURE_INCOMPAT_SUPP_STABLE,
and append experimental features only under CONFIG_BTRFS_DEBUG.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove root and csum_root arguments from scrub_simple_mirror()
Qu Wenruo [Mon, 16 Jan 2023 07:04:13 +0000 (15:04 +0800)]
btrfs: scrub: remove root and csum_root arguments from scrub_simple_mirror()

We don't need to pass the roots as arguments, reading them from the
rb-tree is cheap.  Thus there is really not much need to pre-fetch it
and pass it all the way from scrub_stripe().

And we already have more than enough arguments in scrub_simple_mirror()
and scrub_simple_stripe(), it's better to remove them and only grab
those roots in scrub_simple_mirror().

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
18 months agobtrfs: scrub: remove unused path inside scrub_stripe()
Qu Wenruo [Mon, 16 Jan 2023 07:04:12 +0000 (15:04 +0800)]
btrfs: scrub: remove unused path inside scrub_stripe()

The variable @path is no longer passed into any call sites after commit
18d30ab96149 ("btrfs: scrub: use scrub_simple_mirror() to handle RAID56
data stripe scrub"), thus we can remove the variable completely.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>