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77163 commits

Author SHA1 Message Date
Naohiro Aota
2dd7e7bc02 btrfs: zoned: wait for extent buffer IOs before finishing a zone
Before sending REQ_OP_ZONE_FINISH to a zone, we need to ensure that
ongoing IOs already finished. Or, we will see a "Zone Is Full" error for
the IOs, as the ZONE_FINISH command makes the zone full.

We ensure that with btrfs_wait_block_group_reservations() and
btrfs_wait_ordered_roots() for a data block group. And, for a metadata
block group, the comparison of alloc_offset vs meta_write_pointer mostly
ensures IOs for the allocated region already sent. However, there still
can be a little time frame where the IOs are sent but not yet completed.

Introduce wait_eb_writebacks() to ensure such IOs are completed for a
metadata block group. It walks the buffer_radix to find extent buffers in
the block group and calls wait_on_extent_buffer_writeback() on them.

Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
CC: stable@vger.kernel.org # 5.19+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-13 14:05:18 +02:00
Filipe Manana
a362bb864b btrfs: fix hang during unmount when stopping a space reclaim worker
Often when running generic/562 from fstests we can hang during unmount,
resulting in a trace like this:

  Sep 07 11:52:00 debian9 unknown: run fstests generic/562 at 2022-09-07 11:52:00
  Sep 07 11:55:32 debian9 kernel: INFO: task umount:49438 blocked for more than 120 seconds.
  Sep 07 11:55:32 debian9 kernel:       Not tainted 6.0.0-rc2-btrfs-next-122 #1
  Sep 07 11:55:32 debian9 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  Sep 07 11:55:32 debian9 kernel: task:umount          state:D stack:    0 pid:49438 ppid: 25683 flags:0x00004000
  Sep 07 11:55:32 debian9 kernel: Call Trace:
  Sep 07 11:55:32 debian9 kernel:  <TASK>
  Sep 07 11:55:32 debian9 kernel:  __schedule+0x3c8/0xec0
  Sep 07 11:55:32 debian9 kernel:  ? rcu_read_lock_sched_held+0x12/0x70
  Sep 07 11:55:32 debian9 kernel:  schedule+0x5d/0xf0
  Sep 07 11:55:32 debian9 kernel:  schedule_timeout+0xf1/0x130
  Sep 07 11:55:32 debian9 kernel:  ? lock_release+0x224/0x4a0
  Sep 07 11:55:32 debian9 kernel:  ? lock_acquired+0x1a0/0x420
  Sep 07 11:55:32 debian9 kernel:  ? trace_hardirqs_on+0x2c/0xd0
  Sep 07 11:55:32 debian9 kernel:  __wait_for_common+0xac/0x200
  Sep 07 11:55:32 debian9 kernel:  ? usleep_range_state+0xb0/0xb0
  Sep 07 11:55:32 debian9 kernel:  __flush_work+0x26d/0x530
  Sep 07 11:55:32 debian9 kernel:  ? flush_workqueue_prep_pwqs+0x140/0x140
  Sep 07 11:55:32 debian9 kernel:  ? trace_clock_local+0xc/0x30
  Sep 07 11:55:32 debian9 kernel:  __cancel_work_timer+0x11f/0x1b0
  Sep 07 11:55:32 debian9 kernel:  ? close_ctree+0x12b/0x5b3 [btrfs]
  Sep 07 11:55:32 debian9 kernel:  ? __trace_bputs+0x10b/0x170
  Sep 07 11:55:32 debian9 kernel:  close_ctree+0x152/0x5b3 [btrfs]
  Sep 07 11:55:32 debian9 kernel:  ? evict_inodes+0x166/0x1c0
  Sep 07 11:55:32 debian9 kernel:  generic_shutdown_super+0x71/0x120
  Sep 07 11:55:32 debian9 kernel:  kill_anon_super+0x14/0x30
  Sep 07 11:55:32 debian9 kernel:  btrfs_kill_super+0x12/0x20 [btrfs]
  Sep 07 11:55:32 debian9 kernel:  deactivate_locked_super+0x2e/0xa0
  Sep 07 11:55:32 debian9 kernel:  cleanup_mnt+0x100/0x160
  Sep 07 11:55:32 debian9 kernel:  task_work_run+0x59/0xa0
  Sep 07 11:55:32 debian9 kernel:  exit_to_user_mode_prepare+0x1a6/0x1b0
  Sep 07 11:55:32 debian9 kernel:  syscall_exit_to_user_mode+0x16/0x40
  Sep 07 11:55:32 debian9 kernel:  do_syscall_64+0x48/0x90
  Sep 07 11:55:32 debian9 kernel:  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  Sep 07 11:55:32 debian9 kernel: RIP: 0033:0x7fcde59a57a7
  Sep 07 11:55:32 debian9 kernel: RSP: 002b:00007ffe914217c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  Sep 07 11:55:32 debian9 kernel: RAX: 0000000000000000 RBX: 00007fcde5ae8264 RCX: 00007fcde59a57a7
  Sep 07 11:55:32 debian9 kernel: RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055b57556cdd0
  Sep 07 11:55:32 debian9 kernel: RBP: 000055b57556cba0 R08: 0000000000000000 R09: 00007ffe91420570
  Sep 07 11:55:32 debian9 kernel: R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  Sep 07 11:55:32 debian9 kernel: R13: 000055b57556cdd0 R14: 000055b57556ccb8 R15: 0000000000000000
  Sep 07 11:55:32 debian9 kernel:  </TASK>

What happens is the following:

1) The cleaner kthread tries to start a transaction to delete an unused
   block group, but the metadata reservation can not be satisfied right
   away, so a reservation ticket is created and it starts the async
   metadata reclaim task (fs_info->async_reclaim_work);

2) Writeback for all the filler inodes with an i_size of 2K starts
   (generic/562 creates a lot of 2K files with the goal of filling
   metadata space). We try to create an inline extent for them, but we
   fail when trying to insert the inline extent with -ENOSPC (at
   cow_file_range_inline()) - since this is not critical, we fallback
   to non-inline mode (back to cow_file_range()), reserve extents, create
   extent maps and create the ordered extents;

3) An unmount starts, enters close_ctree();

4) The async reclaim task is flushing stuff, entering the flush states one
   by one, until it reaches RUN_DELAYED_IPUTS. There it runs all current
   delayed iputs.

   After running the delayed iputs and before calling
   btrfs_wait_on_delayed_iputs(), one or more ordered extents complete,
   and btrfs_add_delayed_iput() is called for each one through
   btrfs_finish_ordered_io() -> btrfs_put_ordered_extent(). This results
   in bumping fs_info->nr_delayed_iputs from 0 to some positive value.

   So the async reclaim task blocks at btrfs_wait_on_delayed_iputs() waiting
   for fs_info->nr_delayed_iputs to become 0;

5) The current transaction is committed by the transaction kthread, we then
   start unpinning extents and end up calling btrfs_try_granting_tickets()
   through unpin_extent_range(), since we released some space.
   This results in satisfying the ticket created by the cleaner kthread at
   step 1, waking up the cleaner kthread;

6) At close_ctree() we ask the cleaner kthread to park;

7) The cleaner kthread starts the transaction, deletes the unused block
   group, and then calls kthread_should_park(), which returns true, so it
   parks. And at this point we have the delayed iputs added by the
   completion of the ordered extents still pending;

8) Then later at close_ctree(), when we call:

       cancel_work_sync(&fs_info->async_reclaim_work);

   We hang forever, since the cleaner was parked and no one else can run
   delayed iputs after that, while the reclaim task is waiting for the
   remaining delayed iputs to be completed.

Fix this by waiting for all ordered extents to complete and running the
delayed iputs before attempting to stop the async reclaim tasks. Note that
we can not wait for ordered extents with btrfs_wait_ordered_roots() (or
other similar functions) because that waits for the BTRFS_ORDERED_COMPLETE
flag to be set on an ordered extent, but the delayed iput is added after
that, when doing the final btrfs_put_ordered_extent(). So instead wait for
the work queues used for executing ordered extent completion to be empty,
which works because we do the final put on an ordered extent at
btrfs_finish_ordered_io() (while we are in the unmount context).

Fixes: d6fd0ae25c ("Btrfs: fix missing delayed iputs on unmount")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-13 14:05:13 +02:00
Filipe Manana
8a1f1e3d1e btrfs: fix hang during unmount when stopping block group reclaim worker
During early unmount, at close_ctree(), we try to stop the block group
reclaim task with cancel_work_sync(), but that may hang if the block group
reclaim task is currently at btrfs_relocate_block_group() waiting for the
flag BTRFS_FS_UNFINISHED_DROPS to be cleared from fs_info->flags. During
unmount we only clear that flag later, after trying to stop the block
group reclaim task.

Fix that by clearing BTRFS_FS_UNFINISHED_DROPS before trying to stop the
block group reclaim task and after setting BTRFS_FS_CLOSING_START, so that
if the reclaim task is waiting on that bit, it will stop immediately after
being woken, because it sees the filesystem is closing (with a call to
btrfs_fs_closing()), and then returns immediately with -EINTR.

Fixes: 31e70e5278 ("btrfs: fix hang during unmount when block group reclaim task is running")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-13 14:05:08 +02:00
Qu Wenruo
5da431b71d btrfs: fix the max chunk size and stripe length calculation
[BEHAVIOR CHANGE]
Since commit f6fca3917b ("btrfs: store chunk size in space-info
struct"), btrfs no longer can create larger data chunks than 1G:

  mkfs.btrfs -f -m raid1 -d raid0 $dev1 $dev2 $dev3 $dev4
  mount $dev1 $mnt

  btrfs balance start --full $mnt
  btrfs balance start --full $mnt
  umount $mnt

  btrfs ins dump-tree -t chunk $dev1 | grep "DATA|RAID0" -C 2

Before that offending commit, what we got is a 4G data chunk:

	item 6 key (FIRST_CHUNK_TREE CHUNK_ITEM 9492758528) itemoff 15491 itemsize 176
		length 4294967296 owner 2 stripe_len 65536 type DATA|RAID0
		io_align 65536 io_width 65536 sector_size 4096
		num_stripes 4 sub_stripes 1

Now what we got is only 1G data chunk:

	item 6 key (FIRST_CHUNK_TREE CHUNK_ITEM 6271533056) itemoff 15491 itemsize 176
		length 1073741824 owner 2 stripe_len 65536 type DATA|RAID0
		io_align 65536 io_width 65536 sector_size 4096
		num_stripes 4 sub_stripes 1

This will increase the number of data chunks by the number of devices,
not only increase system chunk usage, but also greatly increase mount
time.

Without a proper reason, we should not change the max chunk size.

[CAUSE]
Previously, we set max data chunk size to 10G, while max data stripe
length to 1G.

Commit f6fca3917b ("btrfs: store chunk size in space-info struct")
completely ignored the 10G limit, but use 1G max stripe limit instead,
causing above shrink in max data chunk size.

[FIX]
Fix the max data chunk size to 10G, and in decide_stripe_size_regular()
we limit stripe_size to 1G manually.

This should only affect data chunks, as for metadata chunks we always
set the max stripe size the same as max chunk size (256M or 1G
depending on fs size).

Now the same script result the same old result:

	item 6 key (FIRST_CHUNK_TREE CHUNK_ITEM 9492758528) itemoff 15491 itemsize 176
		length 4294967296 owner 2 stripe_len 65536 type DATA|RAID0
		io_align 65536 io_width 65536 sector_size 4096
		num_stripes 4 sub_stripes 1

Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Fixes: f6fca3917b ("btrfs: store chunk size in space-info struct")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-06 17:49:58 +02:00
Johannes Thumshirn
6ca64ac276 btrfs: zoned: fix mounting with conventional zones
Since commit 6a921de589 ("btrfs: zoned: introduce
space_info->active_total_bytes"), we're only counting the bytes of a
block group on an active zone as usable for metadata writes. But on a
SMR drive, we don't have active zones and short circuit some of the
logic.

This leads to an error on mount, because we cannot reserve space for
metadata writes.

Fix this by also setting the BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE bit in the
block-group's runtime flag if the zone is a conventional zone.

Fixes: 6a921de589 ("btrfs: zoned: introduce space_info->active_total_bytes")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-05 15:39:10 +02:00
Shin'ichiro Kawasaki
cac5c44c48 btrfs: zoned: set pseudo max append zone limit in zone emulation mode
The commit 7d7672bc5d ("btrfs: convert count_max_extents() to use
fs_info->max_extent_size") introduced a division by
fs_info->max_extent_size. This max_extent_size is initialized with max
zone append limit size of the device btrfs runs on. However, in zone
emulation mode, the device is not zoned then its zone append limit is
zero. This resulted in zero value of fs_info->max_extent_size and caused
zero division error.

Fix the error by setting non-zero pseudo value to max append zone limit
in zone emulation mode. Set the pseudo value based on max_segments as
suggested in the commit c2ae7b772e ("btrfs: zoned: revive
max_zone_append_bytes").

Fixes: 7d7672bc5d ("btrfs: convert count_max_extents() to use fs_info->max_extent_size")
CC: stable@vger.kernel.org # 5.12+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-05 15:32:26 +02:00
Naohiro Aota
d5b81ced74 btrfs: zoned: fix API misuse of zone finish waiting
The commit 2ce543f478 ("btrfs: zoned: wait until zone is finished when
allocation didn't progress") implemented a zone finish waiting mechanism
to the write path of zoned mode. However, using
wait_var_event()/wake_up_all() on fs_info->zone_finish_wait is wrong and
wait_var_event() just hangs because no one ever wakes it up once it goes
into sleep.

Instead, we can simply use wait_on_bit_io() and clear_and_wake_up_bit()
on fs_info->flags with a proper barrier installed.

Fixes: 2ce543f478 ("btrfs: zoned: wait until zone is finished when allocation didn't progress")
CC: stable@vger.kernel.org # 5.16+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-05 15:32:21 +02:00
Anand Jain
f2c3bec215 btrfs: add info when mount fails due to stale replace target
If the replace target device reappears after the suspended replace is
cancelled, it blocks the mount operation as it can't find the matching
replace-item in the metadata. As shown below,

   BTRFS error (device sda5): replace devid present without an active replace item

To overcome this situation, the user can run the command

   btrfs device scan --forget <replace target device>

and try the mount command again. And also, to avoid repeating the issue,
superblock on the devid=0 must be wiped.

   wipefs -a device-path-to-devid=0.

This patch adds some info when this situation occurs.

Reported-by: Samuel Greiner <samuel@balkonien.org>
Link: https://lore.kernel.org/linux-btrfs/b4f62b10-b295-26ea-71f9-9a5c9299d42c@balkonien.org/T/
CC: stable@vger.kernel.org # 5.0+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-23 22:15:21 +02:00
Anand Jain
59a3991984 btrfs: replace: drop assert for suspended replace
If the filesystem mounts with the replace-operation in a suspended state
and try to cancel the suspended replace-operation, we hit the assert. The
assert came from the commit fe97e2e173 ("btrfs: dev-replace: replace's
scrub must not be running in suspended state") that was actually not
required. So just remove it.

 $ mount /dev/sda5 /btrfs

    BTRFS info (device sda5): cannot continue dev_replace, tgtdev is missing
    BTRFS info (device sda5): you may cancel the operation after 'mount -o degraded'

 $ mount -o degraded /dev/sda5 /btrfs <-- success.

 $ btrfs replace cancel /btrfs

    kernel: assertion failed: ret != -ENOTCONN, in fs/btrfs/dev-replace.c:1131
    kernel: ------------[ cut here ]------------
    kernel: kernel BUG at fs/btrfs/ctree.h:3750!

After the patch:

 $ btrfs replace cancel /btrfs

    BTRFS info (device sda5): suspended dev_replace from /dev/sda5 (devid 1) to <missing disk> canceled

Fixes: fe97e2e173 ("btrfs: dev-replace: replace's scrub must not be running in suspended state")
CC: stable@vger.kernel.org # 5.0+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-23 22:15:21 +02:00
Filipe Manana
47bf225a8d btrfs: fix silent failure when deleting root reference
At btrfs_del_root_ref(), if btrfs_search_slot() returns an error, we end
up returning from the function with a value of 0 (success). This happens
because the function returns the value stored in the variable 'err',
which is 0, while the error value we got from btrfs_search_slot() is
stored in the 'ret' variable.

So fix it by setting 'err' with the error value.

Fixes: 8289ed9f93 ("btrfs: replace the BUG_ON in btrfs_del_root_ref with proper error handling")
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-23 22:15:21 +02:00
Omar Sandoval
ced8ecf026 btrfs: fix space cache corruption and potential double allocations
When testing space_cache v2 on a large set of machines, we encountered a
few symptoms:

1. "unable to add free space :-17" (EEXIST) errors.
2. Missing free space info items, sometimes caught with a "missing free
   space info for X" error.
3. Double-accounted space: ranges that were allocated in the extent tree
   and also marked as free in the free space tree, ranges that were
   marked as allocated twice in the extent tree, or ranges that were
   marked as free twice in the free space tree. If the latter made it
   onto disk, the next reboot would hit the BUG_ON() in
   add_new_free_space().
4. On some hosts with no on-disk corruption or error messages, the
   in-memory space cache (dumped with drgn) disagreed with the free
   space tree.

All of these symptoms have the same underlying cause: a race between
caching the free space for a block group and returning free space to the
in-memory space cache for pinned extents causes us to double-add a free
range to the space cache. This race exists when free space is cached
from the free space tree (space_cache=v2) or the extent tree
(nospace_cache, or space_cache=v1 if the cache needs to be regenerated).
struct btrfs_block_group::last_byte_to_unpin and struct
btrfs_block_group::progress are supposed to protect against this race,
but commit d0c2f4fa55 ("btrfs: make concurrent fsyncs wait less when
waiting for a transaction commit") subtly broke this by allowing
multiple transactions to be unpinning extents at the same time.

Specifically, the race is as follows:

1. An extent is deleted from an uncached block group in transaction A.
2. btrfs_commit_transaction() is called for transaction A.
3. btrfs_run_delayed_refs() -> __btrfs_free_extent() runs the delayed
   ref for the deleted extent.
4. __btrfs_free_extent() -> do_free_extent_accounting() ->
   add_to_free_space_tree() adds the deleted extent back to the free
   space tree.
5. do_free_extent_accounting() -> btrfs_update_block_group() ->
   btrfs_cache_block_group() queues up the block group to get cached.
   block_group->progress is set to block_group->start.
6. btrfs_commit_transaction() for transaction A calls
   switch_commit_roots(). It sets block_group->last_byte_to_unpin to
   block_group->progress, which is block_group->start because the block
   group hasn't been cached yet.
7. The caching thread gets to our block group. Since the commit roots
   were already switched, load_free_space_tree() sees the deleted extent
   as free and adds it to the space cache. It finishes caching and sets
   block_group->progress to U64_MAX.
8. btrfs_commit_transaction() advances transaction A to
   TRANS_STATE_SUPER_COMMITTED.
9. fsync calls btrfs_commit_transaction() for transaction B. Since
   transaction A is already in TRANS_STATE_SUPER_COMMITTED and the
   commit is for fsync, it advances.
10. btrfs_commit_transaction() for transaction B calls
    switch_commit_roots(). This time, the block group has already been
    cached, so it sets block_group->last_byte_to_unpin to U64_MAX.
11. btrfs_commit_transaction() for transaction A calls
    btrfs_finish_extent_commit(), which calls unpin_extent_range() for
    the deleted extent. It sees last_byte_to_unpin set to U64_MAX (by
    transaction B!), so it adds the deleted extent to the space cache
    again!

This explains all of our symptoms above:

* If the sequence of events is exactly as described above, when the free
  space is re-added in step 11, it will fail with EEXIST.
* If another thread reallocates the deleted extent in between steps 7
  and 11, then step 11 will silently re-add that space to the space
  cache as free even though it is actually allocated. Then, if that
  space is allocated *again*, the free space tree will be corrupted
  (namely, the wrong item will be deleted).
* If we don't catch this free space tree corruption, it will continue
  to get worse as extents are deleted and reallocated.

The v1 space_cache is synchronously loaded when an extent is deleted
(btrfs_update_block_group() with alloc=0 calls btrfs_cache_block_group()
with load_cache_only=1), so it is not normally affected by this bug.
However, as noted above, if we fail to load the space cache, we will
fall back to caching from the extent tree and may hit this bug.

The easiest fix for this race is to also make caching from the free
space tree or extent tree synchronous. Josef tested this and found no
performance regressions.

A few extra changes fall out of this change. Namely, this fix does the
following, with step 2 being the crucial fix:

1. Factor btrfs_caching_ctl_wait_done() out of
   btrfs_wait_block_group_cache_done() to allow waiting on a caching_ctl
   that we already hold a reference to.
2. Change the call in btrfs_cache_block_group() of
   btrfs_wait_space_cache_v1_finished() to
   btrfs_caching_ctl_wait_done(), which makes us wait regardless of the
   space_cache option.
3. Delete the now unused btrfs_wait_space_cache_v1_finished() and
   space_cache_v1_done().
4. Change btrfs_cache_block_group()'s `int load_cache_only` parameter to
   `bool wait` to more accurately describe its new meaning.
5. Change a few callers which had a separate call to
   btrfs_wait_block_group_cache_done() to use wait = true instead.
6. Make btrfs_wait_block_group_cache_done() static now that it's not
   used outside of block-group.c anymore.

Fixes: d0c2f4fa55 ("btrfs: make concurrent fsyncs wait less when waiting for a transaction commit")
CC: stable@vger.kernel.org # 5.12+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-23 22:13:54 +02:00
Josef Bacik
79d3d1d12e btrfs: don't allow large NOWAIT direct reads
Dylan and Jens reported a problem where they had an io_uring test that
was returning short reads, and bisected it to ee5b46a353 ("btrfs:
increase direct io read size limit to 256 sectors").

The root cause is their test was doing larger reads via io_uring with
NOWAIT and async.  This was triggering a page fault during the direct
read, however the first page was able to work just fine and thus we
submitted a 4k read for a larger iocb.

Btrfs allows for partial IO's in this case specifically because we don't
allow page faults, and thus we'll attempt to do any io that we can,
submit what we could, come back and fault in the rest of the range and
try to do the remaining IO.

However for !is_sync_kiocb() we'll call ->ki_complete() as soon as the
partial dio is done, which is incorrect.  In the sync case we can exit
the iomap code, submit more io's, and return with the amount of IO we
were able to complete successfully.

We were always doing short reads in this case, but for NOWAIT we were
getting saved by the fact that we were limiting direct reads to
sectorsize, and if we were larger than that we would return EAGAIN.

Fix the regression by simply returning EAGAIN in the NOWAIT case with
larger reads, that way io_uring can retry and get the larger IO and have
the fault logic handle everything properly.

This still leaves the AIO short read case, but that existed before this
change.  The way to properly fix this would be to handle partial iocb
completions, but that's a lot of work, for now deal with the regression
in the most straightforward way possible.

Reported-by: Dylan Yudaken <dylany@fb.com>
Fixes: ee5b46a353 ("btrfs: increase direct io read size limit to 256 sectors")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-22 18:08:07 +02:00
Qu Wenruo
4a445b7b61 btrfs: don't merge pages into bio if their page offset is not contiguous
[BUG]
Zygo reported on latest development branch, he could hit
ASSERT()/BUG_ON() caused crash when doing RAID5 recovery (intentionally
corrupt one disk, and let btrfs to recover the data during read/scrub).

And The following minimal reproducer can cause extent state leakage at
rmmod time:

  mkfs.btrfs -f -d raid5 -m raid5 $dev1 $dev2 $dev3 -b 1G > /dev/null
  mount $dev1 $mnt
  fsstress -w -d $mnt -n 25 -s 1660807876
  sync
  fssum -A -f -w /tmp/fssum.saved $mnt
  umount $mnt

  # Wipe the dev1 but keeps its super block
  xfs_io -c "pwrite -S 0x0 1m 1023m" $dev1
  mount $dev1 $mnt
  fssum -r /tmp/fssum.saved $mnt > /dev/null
  umount $mnt
  rmmod btrfs

This will lead to the following extent states leakage:

  BTRFS: state leak: start 499712 end 503807 state 5 in tree 1 refs 1
  BTRFS: state leak: start 495616 end 499711 state 5 in tree 1 refs 1
  BTRFS: state leak: start 491520 end 495615 state 5 in tree 1 refs 1
  BTRFS: state leak: start 487424 end 491519 state 5 in tree 1 refs 1
  BTRFS: state leak: start 483328 end 487423 state 5 in tree 1 refs 1
  BTRFS: state leak: start 479232 end 483327 state 5 in tree 1 refs 1
  BTRFS: state leak: start 475136 end 479231 state 5 in tree 1 refs 1
  BTRFS: state leak: start 471040 end 475135 state 5 in tree 1 refs 1

[CAUSE]
Since commit 7aa51232e2 ("btrfs: pass a btrfs_bio to
btrfs_repair_one_sector"), we always use btrfs_bio->file_offset to
determine the file offset of a page.

But that usage assume that, one bio has all its page having a continuous
page offsets.

Unfortunately that's not true, btrfs only requires the logical bytenr
contiguous when assembling its bios.

From above script, we have one bio looks like this:

  fssum-27671  submit_one_bio: bio logical=217739264 len=36864
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=466944 <<<
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=724992 <<<
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=729088
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=733184
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=737280
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=741376
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=745472
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=749568
  fssum-27671  submit_one_bio:   r/i=5/261 page_offset=753664

Note that the 1st and the 2nd page has non-contiguous page offsets.

This means, at repair time, we will have completely wrong file offset
passed in:

   kworker/u32:2-19927  btrfs_repair_one_sector: r/i=5/261 page_off=729088 file_off=475136 bio_offset=8192

Since the file offset is incorrect, we latter incorrectly set the extent
states, and no way to really release them.

Thus later it causes the leakage.

In fact, this can be even worse, since the file offset is incorrect, we
can hit cases like the incorrect file offset belongs to a HOLE, and
later cause btrfs_num_copies() to trigger error, finally hit
BUG_ON()/ASSERT() later.

[FIX]
Add an extra condition in btrfs_bio_add_page() for uncompressed IO.

Now we will have more strict requirement for bio pages:

- They should all have the same mapping
  (the mapping check is already implied by the call chain)

- Their logical bytenr should be adjacent
  This is the same as the old condition.

- Their page_offset() (file offset) should be adjacent
  This is the new check.
  This would result a slightly increased amount of bios from btrfs
  (needs holes and inside the same stripe boundary to trigger).

  But this would greatly reduce the confusion, as it's pretty common
  to assume a btrfs bio would only contain continuous page cache.

Later we may need extra cleanups, as we no longer needs to handle gaps
between page offsets in endio functions.

Currently this should be the minimal patch to fix commit 7aa51232e2
("btrfs: pass a btrfs_bio to btrfs_repair_one_sector").

Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Fixes: 7aa51232e2 ("btrfs: pass a btrfs_bio to btrfs_repair_one_sector")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-22 18:06:58 +02:00
Filipe Manana
e6e3dec6c3 btrfs: update generation of hole file extent item when merging holes
When punching a hole into a file range that is adjacent with a hole and we
are not using the no-holes feature, we expand the range of the adjacent
file extent item that represents a hole, to save metadata space.

However we don't update the generation of hole file extent item, which
means a full fsync will not log that file extent item if the fsync happens
in a later transaction (since commit 7f30c07288 ("btrfs: stop copying
old file extents when doing a full fsync")).

For example, if we do this:

    $ mkfs.btrfs -f -O ^no-holes /dev/sdb
    $ mount /dev/sdb /mnt
    $ xfs_io -f -c "pwrite -S 0xab 2M 2M" /mnt/foobar
    $ sync

We end up with 2 file extent items in our file:

1) One that represents the hole for the file range [0, 2M), with a
   generation of 7;

2) Another one that represents an extent covering the range [2M, 4M).

After that if we do the following:

    $ xfs_io -c "fpunch 2M 2M" /mnt/foobar

We end up with a single file extent item in the file, which represents a
hole for the range [0, 4M) and with a generation of 7 - because we end
dropping the data extent for range [2M, 4M) and then update the file
extent item that represented the hole at [0, 2M), by increasing
length from 2M to 4M.

Then doing a full fsync and power failing:

    $ xfs_io -c "fsync" /mnt/foobar
    <power failure>

will result in the full fsync not logging the file extent item that
represents the hole for the range [0, 4M), because its generation is 7,
which is lower than the generation of the current transaction (8).
As a consequence, after mounting again the filesystem (after log replay),
the region [2M, 4M) does not have a hole, it still points to the
previous data extent.

So fix this by always updating the generation of existing file extent
items representing holes when we merge/expand them. This solves the
problem and it's the same approach as when we merge prealloc extents that
got written (at btrfs_mark_extent_written()). Setting the generation to
the current transaction's generation is also what we do when merging
the new hole extent map with the previous one or the next one.

A test case for fstests, covering both cases of hole file extent item
merging (to the left and to the right), will be sent soon.

Fixes: 7f30c07288 ("btrfs: stop copying old file extents when doing a full fsync")
CC: stable@vger.kernel.org # 5.18+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-22 18:06:42 +02:00
Zixuan Fu
9ea0106a7a btrfs: fix possible memory leak in btrfs_get_dev_args_from_path()
In btrfs_get_dev_args_from_path(), btrfs_get_bdev_and_sb() can fail if
the path is invalid. In this case, btrfs_get_dev_args_from_path()
returns directly without freeing args->uuid and args->fsid allocated
before, which causes memory leak.

To fix these possible leaks, when btrfs_get_bdev_and_sb() fails,
btrfs_put_dev_args_from_path() is called to clean up the memory.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Fixes: faa775c41d ("btrfs: add a btrfs_get_dev_args_from_path helper")
CC: stable@vger.kernel.org # 5.16
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Zixuan Fu <r33s3n6@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-22 18:06:33 +02:00
Goldwyn Rodrigues
b51111271b btrfs: check if root is readonly while setting security xattr
For a filesystem which has btrfs read-only property set to true, all
write operations including xattr should be denied. However, security
xattr can still be changed even if btrfs ro property is true.

This happens because xattr_permission() does not have any restrictions
on security.*, system.*  and in some cases trusted.* from VFS and
the decision is left to the underlying filesystem. See comments in
xattr_permission() for more details.

This patch checks if the root is read-only before performing the set
xattr operation.

Testcase:

  DEV=/dev/vdb
  MNT=/mnt

  mkfs.btrfs -f $DEV
  mount $DEV $MNT
  echo "file one" > $MNT/f1

  setfattr -n "security.one" -v 2 $MNT/f1
  btrfs property set /mnt ro true

  setfattr -n "security.one" -v 1 $MNT/f1

  umount $MNT

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-22 18:06:30 +02:00
Josef Bacik
899b7f69f2 btrfs: tree-checker: check for overlapping extent items
We're seeing a weird problem in production where we have overlapping
extent items in the extent tree.  It's unclear where these are coming
from, and in debugging we realized there's no check in the tree checker
for this sort of problem.  Add a check to the tree-checker to make sure
that the extents do not overlap each other.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-17 16:20:25 +02:00
Filipe Manana
769030e118 btrfs: fix warning during log replay when bumping inode link count
During log replay, at add_link(), we may increment the link count of
another inode that has a reference that conflicts with a new reference
for the inode currently being processed.

During log replay, at add_link(), we may drop (unlink) a reference from
some inode in the subvolume tree if that reference conflicts with a new
reference found in the log for the inode we are currently processing.

After the unlink, If the link count has decreased from 1 to 0, then we
increment the link count to prevent the inode from being deleted if it's
evicted by an iput() call, because we may have references to add to that
inode later on (and we will fixup its link count later during log replay).

However incrementing the link count from 0 to 1 triggers a warning:

  $ cat fs/inode.c
  (...)
  void inc_nlink(struct inode *inode)
  {
        if (unlikely(inode->i_nlink == 0)) {
                 WARN_ON(!(inode->i_state & I_LINKABLE));
                 atomic_long_dec(&inode->i_sb->s_remove_count);
        }
  (...)

The I_LINKABLE flag is only set when creating an O_TMPFILE file, so it's
never set during log replay.

Most of the time, the warning isn't triggered even if we dropped the last
reference of the conflicting inode, and this is because:

1) The conflicting inode was previously marked for fixup, through a call
   to link_to_fixup_dir(), which increments the inode's link count;

2) And the last iput() on the inode has not triggered eviction of the
   inode, nor was eviction triggered after the iput(). So at add_link(),
   even if we unlink the last reference of the inode, its link count ends
   up being 1 and not 0.

So this means that if eviction is triggered after link_to_fixup_dir() is
called, at add_link() we will read the inode back from the subvolume tree
and have it with a correct link count, matching the number of references
it has on the subvolume tree. So if when we are at add_link() the inode
has exactly one reference only, its link count is 1, and after the unlink
its link count becomes 0.

So fix this by using set_nlink() instead of inc_nlink(), as the former
accepts a transition from 0 to 1 and it's what we use in other similar
contexts (like at link_to_fixup_dir().

Also make add_inode_ref() use set_nlink() instead of inc_nlink() to
bump the link count from 0 to 1.

The warning is actually harmless, but it may scare users. Josef also ran
into it recently.

CC: stable@vger.kernel.org # 5.1+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-17 16:19:50 +02:00
Filipe Manana
7a6b75b799 btrfs: fix lost error handling when looking up extended ref on log replay
During log replay, when processing inode references, if we get an error
when looking up for an extended reference at __add_inode_ref(), we ignore
it and proceed, returning success (0) if no other error happens after the
lookup. This is obviously wrong because in case an extended reference
exists and it encodes some name not in the log, we need to unlink it,
otherwise the filesystem state will not match the state it had after the
last fsync.

So just make __add_inode_ref() return an error it gets from the extended
reference lookup.

Fixes: f186373fef ("btrfs: extended inode refs")
CC: stable@vger.kernel.org # 4.9+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-17 16:19:45 +02:00
Josef Bacik
b40130b23c btrfs: fix lockdep splat with reloc root extent buffers
We have been hitting the following lockdep splat with btrfs/187 recently

  WARNING: possible circular locking dependency detected
  5.19.0-rc8+ #775 Not tainted
  ------------------------------------------------------
  btrfs/752500 is trying to acquire lock:
  ffff97e1875a97b8 (btrfs-treloc-02#2){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110

  but task is already holding lock:
  ffff97e1875a9278 (btrfs-tree-01/1){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (btrfs-tree-01/1){+.+.}-{3:3}:
	 down_write_nested+0x41/0x80
	 __btrfs_tree_lock+0x24/0x110
	 btrfs_init_new_buffer+0x7d/0x2c0
	 btrfs_alloc_tree_block+0x120/0x3b0
	 __btrfs_cow_block+0x136/0x600
	 btrfs_cow_block+0x10b/0x230
	 btrfs_search_slot+0x53b/0xb70
	 btrfs_lookup_inode+0x2a/0xa0
	 __btrfs_update_delayed_inode+0x5f/0x280
	 btrfs_async_run_delayed_root+0x24c/0x290
	 btrfs_work_helper+0xf2/0x3e0
	 process_one_work+0x271/0x590
	 worker_thread+0x52/0x3b0
	 kthread+0xf0/0x120
	 ret_from_fork+0x1f/0x30

  -> #1 (btrfs-tree-01){++++}-{3:3}:
	 down_write_nested+0x41/0x80
	 __btrfs_tree_lock+0x24/0x110
	 btrfs_search_slot+0x3c3/0xb70
	 do_relocation+0x10c/0x6b0
	 relocate_tree_blocks+0x317/0x6d0
	 relocate_block_group+0x1f1/0x560
	 btrfs_relocate_block_group+0x23e/0x400
	 btrfs_relocate_chunk+0x4c/0x140
	 btrfs_balance+0x755/0xe40
	 btrfs_ioctl+0x1ea2/0x2c90
	 __x64_sys_ioctl+0x88/0xc0
	 do_syscall_64+0x38/0x90
	 entry_SYSCALL_64_after_hwframe+0x63/0xcd

  -> #0 (btrfs-treloc-02#2){+.+.}-{3:3}:
	 __lock_acquire+0x1122/0x1e10
	 lock_acquire+0xc2/0x2d0
	 down_write_nested+0x41/0x80
	 __btrfs_tree_lock+0x24/0x110
	 btrfs_lock_root_node+0x31/0x50
	 btrfs_search_slot+0x1cb/0xb70
	 replace_path+0x541/0x9f0
	 merge_reloc_root+0x1d6/0x610
	 merge_reloc_roots+0xe2/0x260
	 relocate_block_group+0x2c8/0x560
	 btrfs_relocate_block_group+0x23e/0x400
	 btrfs_relocate_chunk+0x4c/0x140
	 btrfs_balance+0x755/0xe40
	 btrfs_ioctl+0x1ea2/0x2c90
	 __x64_sys_ioctl+0x88/0xc0
	 do_syscall_64+0x38/0x90
	 entry_SYSCALL_64_after_hwframe+0x63/0xcd

  other info that might help us debug this:

  Chain exists of:
    btrfs-treloc-02#2 --> btrfs-tree-01 --> btrfs-tree-01/1

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-tree-01/1);
				 lock(btrfs-tree-01);
				 lock(btrfs-tree-01/1);
    lock(btrfs-treloc-02#2);

   *** DEADLOCK ***

  7 locks held by btrfs/752500:
   #0: ffff97e292fdf460 (sb_writers#12){.+.+}-{0:0}, at: btrfs_ioctl+0x208/0x2c90
   #1: ffff97e284c02050 (&fs_info->reclaim_bgs_lock){+.+.}-{3:3}, at: btrfs_balance+0x55f/0xe40
   #2: ffff97e284c00878 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: btrfs_relocate_block_group+0x236/0x400
   #3: ffff97e292fdf650 (sb_internal#2){.+.+}-{0:0}, at: merge_reloc_root+0xef/0x610
   #4: ffff97e284c02378 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x1a8/0x5a0
   #5: ffff97e284c023a0 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x1a8/0x5a0
   #6: ffff97e1875a9278 (btrfs-tree-01/1){+.+.}-{3:3}, at: __btrfs_tree_lock+0x24/0x110

  stack backtrace:
  CPU: 1 PID: 752500 Comm: btrfs Not tainted 5.19.0-rc8+ #775
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:

   dump_stack_lvl+0x56/0x73
   check_noncircular+0xd6/0x100
   ? lock_is_held_type+0xe2/0x140
   __lock_acquire+0x1122/0x1e10
   lock_acquire+0xc2/0x2d0
   ? __btrfs_tree_lock+0x24/0x110
   down_write_nested+0x41/0x80
   ? __btrfs_tree_lock+0x24/0x110
   __btrfs_tree_lock+0x24/0x110
   btrfs_lock_root_node+0x31/0x50
   btrfs_search_slot+0x1cb/0xb70
   ? lock_release+0x137/0x2d0
   ? _raw_spin_unlock+0x29/0x50
   ? release_extent_buffer+0x128/0x180
   replace_path+0x541/0x9f0
   merge_reloc_root+0x1d6/0x610
   merge_reloc_roots+0xe2/0x260
   relocate_block_group+0x2c8/0x560
   btrfs_relocate_block_group+0x23e/0x400
   btrfs_relocate_chunk+0x4c/0x140
   btrfs_balance+0x755/0xe40
   btrfs_ioctl+0x1ea2/0x2c90
   ? lock_is_held_type+0xe2/0x140
   ? lock_is_held_type+0xe2/0x140
   ? __x64_sys_ioctl+0x88/0xc0
   __x64_sys_ioctl+0x88/0xc0
   do_syscall_64+0x38/0x90
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

This isn't necessarily new, it's just tricky to hit in practice.  There
are two competing things going on here.  With relocation we create a
snapshot of every fs tree with a reloc tree.  Any extent buffers that
get initialized here are initialized with the reloc root lockdep key.
However since it is a snapshot, any blocks that are currently in cache
that originally belonged to the fs tree will have the normal tree
lockdep key set.  This creates the lock dependency of

  reloc tree -> normal tree

for the extent buffer locking during the first phase of the relocation
as we walk down the reloc root to relocate blocks.

However this is problematic because the final phase of the relocation is
merging the reloc root into the original fs root.  This involves
searching down to any keys that exist in the original fs root and then
swapping the relocated block and the original fs root block.  We have to
search down to the fs root first, and then go search the reloc root for
the block we need to replace.  This creates the dependency of

  normal tree -> reloc tree

which is why lockdep complains.

Additionally even if we were to fix this particular mismatch with a
different nesting for the merge case, we're still slotting in a block
that has a owner of the reloc root objectid into a normal tree, so that
block will have its lockdep key set to the tree reloc root, and create a
lockdep splat later on when we wander into that block from the fs root.

Unfortunately the only solution here is to make sure we do not set the
lockdep key to the reloc tree lockdep key normally, and then reset any
blocks we wander into from the reloc root when we're doing the merged.

This solves the problem of having mixed tree reloc keys intermixed with
normal tree keys, and then allows us to make sure in the merge case we
maintain the lock order of

  normal tree -> reloc tree

We handle this by setting a bit on the reloc root when we do the search
for the block we want to relocate, and any block we search into or COW
at that point gets set to the reloc tree key.  This works correctly
because we only ever COW down to the parent node, so we aren't resetting
the key for the block we're linking into the fs root.

With this patch we no longer have the lockdep splat in btrfs/187.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-17 16:19:12 +02:00
Josef Bacik
0a27a0474d btrfs: move lockdep class helpers to locking.c
These definitions exist in disk-io.c, which is not related to the
locking.  Move this over to locking.h/c where it makes more sense.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-17 16:19:10 +02:00
Zixuan Fu
85f02d6c85 btrfs: unset reloc control if transaction commit fails in prepare_to_relocate()
In btrfs_relocate_block_group(), the rc is allocated.  Then
btrfs_relocate_block_group() calls

relocate_block_group()
  prepare_to_relocate()
    set_reloc_control()

that assigns rc to the variable fs_info->reloc_ctl. When
prepare_to_relocate() returns, it calls

btrfs_commit_transaction()
  btrfs_start_dirty_block_groups()
    btrfs_alloc_path()
      kmem_cache_zalloc()

which may fail for example (or other errors could happen). When the
failure occurs, btrfs_relocate_block_group() detects the error and frees
rc and doesn't set fs_info->reloc_ctl to NULL. After that, in
btrfs_init_reloc_root(), rc is retrieved from fs_info->reloc_ctl and
then used, which may cause a use-after-free bug.

This possible bug can be triggered by calling btrfs_ioctl_balance()
before calling btrfs_ioctl_defrag().

To fix this possible bug, in prepare_to_relocate(), check if
btrfs_commit_transaction() fails. If the failure occurs,
unset_reloc_control() is called to set fs_info->reloc_ctl to NULL.

The error log in our fault-injection testing is shown as follows:

  [   58.751070] BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x7ca/0x920 [btrfs]
  ...
  [   58.753577] Call Trace:
  ...
  [   58.755800]  kasan_report+0x45/0x60
  [   58.756066]  btrfs_init_reloc_root+0x7ca/0x920 [btrfs]
  [   58.757304]  record_root_in_trans+0x792/0xa10 [btrfs]
  [   58.757748]  btrfs_record_root_in_trans+0x463/0x4f0 [btrfs]
  [   58.758231]  start_transaction+0x896/0x2950 [btrfs]
  [   58.758661]  btrfs_defrag_root+0x250/0xc00 [btrfs]
  [   58.759083]  btrfs_ioctl_defrag+0x467/0xa00 [btrfs]
  [   58.759513]  btrfs_ioctl+0x3c95/0x114e0 [btrfs]
  ...
  [   58.768510] Allocated by task 23683:
  [   58.768777]  ____kasan_kmalloc+0xb5/0xf0
  [   58.769069]  __kmalloc+0x227/0x3d0
  [   58.769325]  alloc_reloc_control+0x10a/0x3d0 [btrfs]
  [   58.769755]  btrfs_relocate_block_group+0x7aa/0x1e20 [btrfs]
  [   58.770228]  btrfs_relocate_chunk+0xf1/0x760 [btrfs]
  [   58.770655]  __btrfs_balance+0x1326/0x1f10 [btrfs]
  [   58.771071]  btrfs_balance+0x3150/0x3d30 [btrfs]
  [   58.771472]  btrfs_ioctl_balance+0xd84/0x1410 [btrfs]
  [   58.771902]  btrfs_ioctl+0x4caa/0x114e0 [btrfs]
  ...
  [   58.773337] Freed by task 23683:
  ...
  [   58.774815]  kfree+0xda/0x2b0
  [   58.775038]  free_reloc_control+0x1d6/0x220 [btrfs]
  [   58.775465]  btrfs_relocate_block_group+0x115c/0x1e20 [btrfs]
  [   58.775944]  btrfs_relocate_chunk+0xf1/0x760 [btrfs]
  [   58.776369]  __btrfs_balance+0x1326/0x1f10 [btrfs]
  [   58.776784]  btrfs_balance+0x3150/0x3d30 [btrfs]
  [   58.777185]  btrfs_ioctl_balance+0xd84/0x1410 [btrfs]
  [   58.777621]  btrfs_ioctl+0x4caa/0x114e0 [btrfs]
  ...

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Zixuan Fu <r33s3n6@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-17 16:18:58 +02:00
Josef Bacik
74944c8736 btrfs: reset RO counter on block group if we fail to relocate
With the automatic block group reclaim code we will preemptively try to
mark the block group RO before we start the relocation.  We do this to
make sure we should actually try to relocate the block group.

However if we hit an error during the actual relocation we won't clean
up our RO counter and the block group will remain RO.  This was observed
internally with file systems reporting less space available from df when
we had failed background relocations.

Fix this by doing the dec_ro in the error case.

Fixes: 18bb8bbf13 ("btrfs: zoned: automatically reclaim zones")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-27 21:23:16 +02:00
Christoph Hellwig
0b078d9db8 btrfs: don't call btrfs_page_set_checked in finish_compressed_bio_read
This flag was used to communicate that the low-level compression code
already did verify the checksum to the high-level I/O completion code.

But it has been unused for a long time as the upper btrfs_bio for the
decompressed data had a NULL csum pointer basically since that pointer
existed and the code already checks for that a little later.

Note that this does not affect the other use of the checked flag, which
is only used for the COW fixup worker.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 19:56:16 +02:00
Christoph Hellwig
81bd9328ab btrfs: fix repair of compressed extents
Currently the checksum of compressed extents is verified based on the
compressed data and the lower btrfs_bio, but the actual repair process
is driven by end_bio_extent_readpage on the upper btrfs_bio for the
decompressed data.

This has a bunch of issues, including not being able to properly
communicate the failed mirror up in case that the I/O submission got
preempted, a general loss of if an error was an I/O error or a checksum
verification failure, but most importantly that this design causes
btrfs_clean_io_failure to eventually write back the uncompressed good
data onto the disk sectors that are supposed to contain compressed data.

Fix this by moving the repair to the lower btrfs_bio.  To do so, a fair
amount of code has to be reshuffled:

 a) the lower btrfs_bio now needs a valid csum pointer.  The easiest way
    to achieve that is to pass NULL btrfs_lookup_bio_sums and just use
    the btrfs_bio management of csums.  For a compressed_bio that is
    split into multiple btrfs_bios this means additional memory
    allocations, but the code becomes a lot more regular.
 b) checksum verification now runs directly on the lower btrfs_bio instead
    of the compressed_bio.  This actually nicely simplifies the end I/O
    processing.
 c) btrfs_repair_one_sector can't just look up the logical address for
    the file offset any more, as there is no corresponding relative
    offsets that apply to the file offset and the logic address for
    compressed extents.  Instead require that the saved bvec_iter in the
    btrfs_bio is filled out for all read bios and use that, which again
    removes a fair amount of code.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 19:56:16 +02:00
Christoph Hellwig
7959bd4411 btrfs: remove the start argument to check_data_csum and export
Derive the value of start from the btrfs_bio now that ->file_offset is
always valid.  Also export and rename the function so it's available
outside of inode.c as we'll need that soon.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-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>
2022-07-25 19:55:32 +02:00
Christoph Hellwig
7aa51232e2 btrfs: pass a btrfs_bio to btrfs_repair_one_sector
Pass the btrfs_bio instead of the plain bio to btrfs_repair_one_sector,
and remove the start and failed_mirror arguments in favor of deriving
them from the btrfs_bio.  For this to work ensure that the file_offset
field is also initialized for buffered I/O.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-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>
2022-07-25 19:55:19 +02:00
Christoph Hellwig
524bcd1e17 btrfs: simplify the pending I/O counting in struct compressed_bio
Instead of counting the sectors just count the bios, with an extra
reference held during submission.  This significantly simplifies the
submission side error handling.

This slightly changes completion and error handling of
btrfs_submit_compressed_{read,write} because with the old code the
compressed_bio could have been completed in
submit_compressed_{read,write} only if there was an error during
submission for one of the lower bio, whilst with the new code there is a
chance for this to happen even for successful submission if the all the
lower bios complete before the end of the function is reached.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 19:54:47 +02:00
Christoph Hellwig
c144c63fd3 btrfs: repair all known bad mirrors
When there is more than a single level of redundancy there can also be
multiple bad mirrors, and the current read repair code only repairs the
last bad one.

Restructure btrfs_repair_one_sector so that it records the originally
failed mirror and the number of copies, and then repair all known bad
copies until we reach the originally failed copy in clean_io_failure.
Note that this also means the read repair reads will always start from
the next bad mirror and not mirror 0.

This fixes btrfs/265 in xfstests.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:43 +02:00
Christoph Hellwig
d28beb3e81 btrfs: merge btrfs_dev_stat_print_on_error with its only caller
Fold it into the only caller.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Filipe Manana
723df2bcc9 btrfs: join running log transaction when logging new name
When logging a new name, in case of a rename, we pin the log before
changing it. We then either delete a directory entry from the log or
insert a key range item to mark the old name for deletion on log replay.

However when doing one of those log changes we may have another task that
started writing out the log (at btrfs_sync_log()) and it started before
we pinned the log root. So we may end up changing a log tree while its
writeback is being started by another task syncing the log. This can lead
to inconsistencies in a log tree and other unexpected results during log
replay, because we can get some committed node pointing to a node/leaf
that ends up not getting written to disk before the next log commit.

The problem, conceptually, started to happen in commit 88d2beec7e
("btrfs: avoid logging all directory changes during renames"), because
there we started to update the log without joining its current transaction
first.

However the problem only became visible with commit 259c4b96d7
("btrfs: stop doing unnecessary log updates during a rename"), and that is
because we used to pin the log at btrfs_rename() and then before entering
btrfs_log_new_name(), when unlinking the old dentry, we ended up at
btrfs_del_inode_ref_in_log() and btrfs_del_dir_entries_in_log(). Both
of them join the current log transaction, effectively waiting for any log
transaction writeout (due to acquiring the root's log_mutex). This made it
safe even after leaving the current log transaction, because we remained
with the log pinned when we called btrfs_log_new_name().

Then in commit 259c4b96d7 ("btrfs: stop doing unnecessary log updates
during a rename"), we removed the log pinning from btrfs_rename() and
stopped calling btrfs_del_inode_ref_in_log() and
btrfs_del_dir_entries_in_log() during the rename, and started to do all
the needed work at btrfs_log_new_name(), but without joining the current
log transaction, only pinning the log, which is racy because another task
may have started writeout of the log tree right before we pinned the log.

Both commits landed in kernel 5.18, so it doesn't make any practical
difference which should be blamed, but I'm blaming the second commit only
because with the first one, by chance, the problem did not happen due to
the fact we joined the log transaction after pinning the log and unpinned
it only after calling btrfs_log_new_name().

So make btrfs_log_new_name() join the current log transaction instead of
pinning it, so that we never do log updates if it's writeout is starting.

Fixes: 259c4b96d7 ("btrfs: stop doing unnecessary log updates during a rename")
CC: stable@vger.kernel.org # 5.18+
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Tested-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Nikolay Borisov
fc8b235fdc btrfs: simplify error handling in btrfs_lookup_dentry
In btrfs_lookup_dentry releasing the reference of the sub_root and the
running orphan cleanup should only happen if the dentry found actually
represents a subvolume. This can only be true in the 'else' branch as
otherwise either fixup_tree_root_location returned an ENOENT error, in
which case sub_root wouldn't have been changed or if we got a different
errno this means btrfs_get_fs_root couldn't have executed successfully
again meaning sub_root will equal to root. So simplify all the branches
by moving the code into the 'else'.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Filipe Manana
0d8869fb6b btrfs: send: always use the rbtree based inode ref management infrastructure
After the patch "btrfs: send: fix sending link commands for existing file
paths", we now have two infrastructures to detect and eliminate duplicated
inode references (due to names that got removed and re-added between the
send and parent snapshots):

1) One that works on a single inode ref/extref item;

2) A new one that works acrosss all ref/extref items for an inode, and
   it's also more efficient because even in the single ref/extref item
   case, it does not do a linear search for all the names encoded in the
   ref/extref item, it uses red black trees to speedup up the search.

There's no good reason to keep both infrastructures, we can use the new
one everywhere, and it's always more efficient.

So remove the old infrastructure and change all sites that are using it
to use the new one.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
BingJing Chang
3aa5bd367f btrfs: send: fix sending link commands for existing file paths
There is a bug sending link commands for existing file paths. When we're
processing an inode, we go over all references. All the new file paths are
added to the "new_refs" list. And all the deleted file paths are added to
the "deleted_refs" list. In the end, when we finish processing the inode,
we iterate over all the items in the "new_refs" list and send link commands
for those file paths. After that, we go over all the items in the
"deleted_refs" list and send unlink commands for them. If there are
duplicated file paths in both lists, we will try to create them before we
remove them. Then the receiver gets an -EEXIST error when trying the link
operations.

Example for having duplicated file paths in both list:

  $ btrfs subvolume create vol

  # create a file and 2000 hard links to the same inode
  $ touch vol/foo
  $ for i in {1..2000}; do link vol/foo vol/$i ; done

  # take a snapshot for a parent snapshot
  $ btrfs subvolume snapshot -r vol snap1

  # remove 2000 hard links and re-create the last 1000 links
  $ for i in {1..2000}; do rm vol/$i; done;
  $ for i in {1001..2000}; do link vol/foo vol/$i; done

  # take another one for a send snapshot
  $ btrfs subvolume snapshot -r vol snap2

  $ mkdir receive_dir
  $ btrfs send snap2 -p snap1 | btrfs receive receive_dir/
  At subvol snap2
  link 1238 -> foo
  ERROR: link 1238 -> foo failed: File exists

In this case, we will have the same file paths added to both lists. In the
parent snapshot, reference paths {1..1237} are stored in inode references,
but reference paths {1238..2000} are stored in inode extended references.
In the send snapshot, all reference paths {1001..2000} are stored in inode
references. During the incremental send, we process their inode references
first. In record_changed_ref(), we iterate all its inode references in the
send/parent snapshot. For every inode reference, we also use find_iref() to
check whether the same file path also appears in the parent/send snapshot
or not. Inode references {1238..2000} which appear in the send snapshot but
not in the parent snapshot are added to the "new_refs" list. On the other
hand, Inode references {1..1000} which appear in the parent snapshot but
not in the send snapshot are added to the "deleted_refs" list. Next, when
we process their inode extended references, reference paths {1238..2000}
are added to the "deleted_refs" list because all of them only appear in the
parent snapshot. Now two lists contain items as below:
"new_refs" list: {1238..2000}
"deleted_refs" list: {1..1000}, {1238..2000}

Reference paths {1238..2000} appear in both lists. And as the processing
order mentioned about before, the receiver gets an -EEXIST error when trying
the link operations.

To fix the bug, the idea is to process the "deleted_refs" list before
the "new_refs" list. However, it's not easy to reshuffle the processing
order. For one reason, if we do so, we may unlink all the existing paths
first, there's no valid path anymore for links. And it's inefficient
because we do a bunch of unlinks followed by links for the same paths.
Moreover, it makes less sense to have duplications in both lists. A
reference path cannot not only be regarded as new but also has been seen in
the past, or we won't call it a new path. However, it's also not a good
idea to make find_iref() check a reference against all inode references
and all inode extended references because it may result in large disk
reads.

So we introduce two rbtrees to make the references easier for lookups.
And we also introduce record_new_ref_if_needed() and
record_deleted_ref_if_needed() for changed_ref() to check and remove
duplicated references early.

Reviewed-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
BingJing Chang
71ecfc133b btrfs: send: introduce recorded_ref_alloc and recorded_ref_free
Introduce wrappers to allocate and free recorded_ref structures.

Reviewed-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
2ce543f478 btrfs: zoned: wait until zone is finished when allocation didn't progress
When the allocated position doesn't progress, we cannot submit IOs to
finish a block group, but there should be ongoing IOs that will finish a
block group. So, in that case, we wait for a zone to be finished and retry
the allocation after that.

Introduce a new flag BTRFS_FS_NEED_ZONE_FINISH for fs_info->flags to
indicate we need a zone finish to have proceeded. The flag is set when the
allocator detected it cannot activate a new block group. And, it is cleared
once a zone is finished.

CC: stable@vger.kernel.org # 5.16+
Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
898793d992 btrfs: zoned: write out partially allocated region
cow_file_range() works in an all-or-nothing way: if it fails to allocate an
extent for a part of the given region, it gives up all the region including
the successfully allocated parts. On cow_file_range(), run_delalloc_zoned()
writes data for the region only when it successfully allocate all the
region.

This all-or-nothing allocation and write-out are problematic when available
space in all the block groups are get tight with the active zone
restriction. btrfs_reserve_extent() try hard to utilize the left space in
the active block groups and gives up finally and fails with
-ENOSPC. However, if we send IOs for the successfully allocated region, we
can finish a zone and can continue on the rest of the allocation on a newly
allocated block group.

This patch implements the partial write-out for run_delalloc_zoned(). With
this patch applied, cow_file_range() returns -EAGAIN to tell the caller to
do something to progress the further allocation, and tells the successfully
allocated region with done_offset. Furthermore, the zoned extent allocator
returns -EAGAIN to tell cow_file_range() going back to the caller side.

Actually, we still need to wait for an IO to complete to continue the
allocation. The next patch implements that part.

CC: stable@vger.kernel.org # 5.16+
Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
b6a98021e4 btrfs: zoned: activate necessary block group
There are two places where allocating a chunk is not enough. These two
places are trying to ensure the space by allocating a chunk. To meet the
condition for active_total_bytes, we also need to activate a block group
there.

CC: stable@vger.kernel.org # 5.16+
Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
b093151391 btrfs: zoned: activate metadata block group on flush_space
For metadata space on zoned filesystem, reaching ALLOC_CHUNK{,_FORCE}
means we don't have enough space left in the active_total_bytes. Before
allocating a new chunk, we can try to activate an existing block group
in this case.

Also, allocating a chunk is not enough to grant a ticket for metadata
space on zoned filesystem we need to activate the block group to
increase the active_total_bytes.

btrfs_zoned_activate_one_bg() implements the activation feature. It will
activate a block group by (maybe) finishing a block group. It will give up
activating a block group if it cannot finish any block group.

CC: stable@vger.kernel.org # 5.16+
Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
79417d040f btrfs: zoned: disable metadata overcommit for zoned
The metadata overcommit makes the space reservation flexible but it is also
harmful to active zone tracking. Since we cannot finish a block group from
the metadata allocation context, we might not activate a new block group
and might not be able to actually write out the overcommit reservations.

So, disable metadata overcommit for zoned filesystems. We will ensure
the reservations are under active_total_bytes in the following patches.

CC: stable@vger.kernel.org # 5.16+
Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
6a921de589 btrfs: zoned: introduce space_info->active_total_bytes
The active_total_bytes, like the total_bytes, accounts for the total bytes
of active block groups in the space_info.

With an introduction of active_total_bytes, we can check if the reserved
bytes can be written to the block groups without activating a new block
group. The check is necessary for metadata allocation on zoned
filesystem. We cannot finish a block group, which may require waiting
for the current transaction, from the metadata allocation context.
Instead, we need to ensure the ongoing allocation (reserved bytes) fits
in active block groups.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:42 +02:00
Naohiro Aota
393f646e34 btrfs: zoned: finish least available block group on data bg allocation
When we run out of active zones and no sufficient space is left in any
block groups, we need to finish one block group to make room to activate a
new block group.

However, we cannot do this for metadata block groups because we can cause a
deadlock by waiting for a running transaction commit. So, do that only for
a data block group.

Furthermore, the block group to be finished has two requirements. First,
the block group must not have reserved bytes left. Having reserved bytes
means we have an allocated region but did not yet send bios for it. If that
region is allocated by the thread calling btrfs_zone_finish(), it results
in a deadlock.

Second, the block group to be finished must not be a SYSTEM block
group. Finishing a SYSTEM block group easily breaks further chunk
allocation by nullifying the SYSTEM free space.

In a certain case, we cannot find any zone finish candidate or
btrfs_zone_finish() may fail. In that case, we fall back to split the
allocation bytes and fill the last spaces left in the block groups.

CC: stable@vger.kernel.org # 5.16+
Fixes: afba2bc036 ("btrfs: zoned: implement active zone tracking")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Naohiro Aota
bb9950d3df btrfs: let can_allocate_chunk return error
For the later patch, convert the return type from bool to int and return
errors. No functional changes.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Naohiro Aota
d760156601 btrfs: use fs_info->max_extent_size in get_extent_max_capacity()
Use fs_info->max_extent_size also in get_extent_max_capacity() for the
completeness. This is only used for defrag and not really necessary to fix
the metadata reservation size. But, it still suppresses unnecessary defrag
operations.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Naohiro Aota
7d7672bc5d btrfs: convert count_max_extents() to use fs_info->max_extent_size
If count_max_extents() uses BTRFS_MAX_EXTENT_SIZE to calculate the number
of extents needed, btrfs release the metadata reservation too much on its
way to write out the data.

Now that BTRFS_MAX_EXTENT_SIZE is replaced with fs_info->max_extent_size,
convert count_max_extents() to use it instead, and fix the calculation of
the metadata reservation.

CC: stable@vger.kernel.org # 5.12+
Fixes: d8e3fb106f ("btrfs: zoned: use ZONE_APPEND write for zoned mode")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Naohiro Aota
f7b12a62f0 btrfs: replace BTRFS_MAX_EXTENT_SIZE with fs_info->max_extent_size
On zoned filesystem, data write out is limited by max_zone_append_size,
and a large ordered extent is split according the size of a bio. OTOH,
the number of extents to be written is calculated using
BTRFS_MAX_EXTENT_SIZE, and that estimated number is used to reserve the
metadata bytes to update and/or create the metadata items.

The metadata reservation is done at e.g, btrfs_buffered_write() and then
released according to the estimation changes. Thus, if the number of extent
increases massively, the reserved metadata can run out.

The increase of the number of extents easily occurs on zoned filesystem
if BTRFS_MAX_EXTENT_SIZE > max_zone_append_size. And, it causes the
following warning on a small RAM environment with disabling metadata
over-commit (in the following patch).

[75721.498492] ------------[ cut here ]------------
[75721.505624] BTRFS: block rsv 1 returned -28
[75721.512230] WARNING: CPU: 24 PID: 2327559 at fs/btrfs/block-rsv.c:537 btrfs_use_block_rsv+0x560/0x760 [btrfs]
[75721.581854] CPU: 24 PID: 2327559 Comm: kworker/u64:10 Kdump: loaded Tainted: G        W         5.18.0-rc2-BTRFS-ZNS+ #109
[75721.597200] Hardware name: Supermicro Super Server/H12SSL-NT, BIOS 2.0 02/22/2021
[75721.607310] Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
[75721.616209] RIP: 0010:btrfs_use_block_rsv+0x560/0x760 [btrfs]
[75721.646649] RSP: 0018:ffffc9000fbdf3e0 EFLAGS: 00010286
[75721.654126] RAX: 0000000000000000 RBX: 0000000000004000 RCX: 0000000000000000
[75721.663524] RDX: 0000000000000004 RSI: 0000000000000008 RDI: fffff52001f7be6e
[75721.672921] RBP: ffffc9000fbdf420 R08: 0000000000000001 R09: ffff889f8d1fc6c7
[75721.682493] R10: ffffed13f1a3f8d8 R11: 0000000000000001 R12: ffff88980a3c0e28
[75721.692284] R13: ffff889b66590000 R14: ffff88980a3c0e40 R15: ffff88980a3c0e8a
[75721.701878] FS:  0000000000000000(0000) GS:ffff889f8d000000(0000) knlGS:0000000000000000
[75721.712601] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[75721.720726] CR2: 000055d12e05c018 CR3: 0000800193594000 CR4: 0000000000350ee0
[75721.730499] Call Trace:
[75721.735166]  <TASK>
[75721.739886]  btrfs_alloc_tree_block+0x1e1/0x1100 [btrfs]
[75721.747545]  ? btrfs_alloc_logged_file_extent+0x550/0x550 [btrfs]
[75721.756145]  ? btrfs_get_32+0xea/0x2d0 [btrfs]
[75721.762852]  ? btrfs_get_32+0xea/0x2d0 [btrfs]
[75721.769520]  ? push_leaf_left+0x420/0x620 [btrfs]
[75721.776431]  ? memcpy+0x4e/0x60
[75721.781931]  split_leaf+0x433/0x12d0 [btrfs]
[75721.788392]  ? btrfs_get_token_32+0x580/0x580 [btrfs]
[75721.795636]  ? push_for_double_split.isra.0+0x420/0x420 [btrfs]
[75721.803759]  ? leaf_space_used+0x15d/0x1a0 [btrfs]
[75721.811156]  btrfs_search_slot+0x1bc3/0x2790 [btrfs]
[75721.818300]  ? lock_downgrade+0x7c0/0x7c0
[75721.824411]  ? free_extent_buffer.part.0+0x107/0x200 [btrfs]
[75721.832456]  ? split_leaf+0x12d0/0x12d0 [btrfs]
[75721.839149]  ? free_extent_buffer.part.0+0x14f/0x200 [btrfs]
[75721.846945]  ? free_extent_buffer+0x13/0x20 [btrfs]
[75721.853960]  ? btrfs_release_path+0x4b/0x190 [btrfs]
[75721.861429]  btrfs_csum_file_blocks+0x85c/0x1500 [btrfs]
[75721.869313]  ? rcu_read_lock_sched_held+0x16/0x80
[75721.876085]  ? lock_release+0x552/0xf80
[75721.881957]  ? btrfs_del_csums+0x8c0/0x8c0 [btrfs]
[75721.888886]  ? __kasan_check_write+0x14/0x20
[75721.895152]  ? do_raw_read_unlock+0x44/0x80
[75721.901323]  ? _raw_write_lock_irq+0x60/0x80
[75721.907983]  ? btrfs_global_root+0xb9/0xe0 [btrfs]
[75721.915166]  ? btrfs_csum_root+0x12b/0x180 [btrfs]
[75721.921918]  ? btrfs_get_global_root+0x820/0x820 [btrfs]
[75721.929166]  ? _raw_write_unlock+0x23/0x40
[75721.935116]  ? unpin_extent_cache+0x1e3/0x390 [btrfs]
[75721.942041]  btrfs_finish_ordered_io.isra.0+0xa0c/0x1dc0 [btrfs]
[75721.949906]  ? try_to_wake_up+0x30/0x14a0
[75721.955700]  ? btrfs_unlink_subvol+0xda0/0xda0 [btrfs]
[75721.962661]  ? rcu_read_lock_sched_held+0x16/0x80
[75721.969111]  ? lock_acquire+0x41b/0x4c0
[75721.974982]  finish_ordered_fn+0x15/0x20 [btrfs]
[75721.981639]  btrfs_work_helper+0x1af/0xa80 [btrfs]
[75721.988184]  ? _raw_spin_unlock_irq+0x28/0x50
[75721.994643]  process_one_work+0x815/0x1460
[75722.000444]  ? pwq_dec_nr_in_flight+0x250/0x250
[75722.006643]  ? do_raw_spin_trylock+0xbb/0x190
[75722.013086]  worker_thread+0x59a/0xeb0
[75722.018511]  kthread+0x2ac/0x360
[75722.023428]  ? process_one_work+0x1460/0x1460
[75722.029431]  ? kthread_complete_and_exit+0x30/0x30
[75722.036044]  ret_from_fork+0x22/0x30
[75722.041255]  </TASK>
[75722.045047] irq event stamp: 0
[75722.049703] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[75722.057610] hardirqs last disabled at (0): [<ffffffff8118a94a>] copy_process+0x1c1a/0x66b0
[75722.067533] softirqs last  enabled at (0): [<ffffffff8118a989>] copy_process+0x1c59/0x66b0
[75722.077423] softirqs last disabled at (0): [<0000000000000000>] 0x0
[75722.085335] ---[ end trace 0000000000000000 ]---

To fix the estimation, we need to introduce fs_info->max_extent_size to
replace BTRFS_MAX_EXTENT_SIZE, which allow setting the different size for
regular vs zoned filesystem.

Set fs_info->max_extent_size to BTRFS_MAX_EXTENT_SIZE by default. On zoned
filesystem, it is set to fs_info->max_zone_append_size.

CC: stable@vger.kernel.org # 5.12+
Fixes: d8e3fb106f ("btrfs: zoned: use ZONE_APPEND write for zoned mode")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Naohiro Aota
c2ae7b772e btrfs: zoned: revive max_zone_append_bytes
This patch is basically a revert of commit 5a80d1c6a2 ("btrfs: zoned:
remove max_zone_append_size logic"), but without unnecessary ASSERT and
check. The max_zone_append_size will be used as a hint to estimate the
number of extents to cover delalloc/writeback region in the later commits.

The size of a ZONE APPEND bio is also limited by queue_max_segments(), so
this commit considers it to calculate max_zone_append_size. Technically, a
bio can be larger than queue_max_segments() * PAGE_SIZE if the pages are
contiguous. But, it is safe to consider "queue_max_segments() * PAGE_SIZE"
as an upper limit of an extent size to calculate the number of extents
needed to write data.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Filipe Manana
cf2404a976 btrfs: add optimized btrfs_ino() version for 64 bits systems
Currently btrfs_ino() tries to use first the objectid of the inode's
location key. This is to avoid truncation of the inode number on 32 bits
platforms because the i_ino field of struct inode has the unsigned long
type, while the objectid is a 64 bits unsigned type (u64) on every system.
This logic was added in commit 33345d0152 ("Btrfs: Always use 64bit
inode number").

However if we are running on a 64 bits system, we can always directly
return the i_ino value from struct inode, which eliminates the need for
he special if statement that tests for a location key type of
BTRFS_ROOT_ITEM_KEY - in which case i_ino may not have the same value as
the objectid in the inode's location objectid, it may have a value of
BTRFS_EMPTY_SUBVOL_DIR_OBJECTID, for the case of snapshots of trees with
subvolumes/snapshots inside them.

So add a special version for 64 bits system that directly returns i_ino
of struct inode. This eliminates one branch and reduces the overall code
size, since btrfs_ino() is an inline function that is extensively used.

Before:

$ size fs/btrfs/btrfs.ko
   text	   data	    bss	    dec	    hex	filename
1617487	 189240	  29032	1835759	 1c02ef	fs/btrfs/btrfs.ko

After:

$ size fs/btrfs/btrfs.ko
   text	   data	    bss	    dec	    hex	filename
1612028	 189180	  29032	1830240	 1bed60	fs/btrfs/btrfs.ko

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Filipe Manana
adac558416 btrfs: set the objectid of the btree inode's location key
We currently don't use the location key of the btree inode, its content
is set to zeroes, as it's a special inode that is not persisted (it has
no inode item stored in any btree).

At btrfs_ino(), an inline function used extensively in btrfs, we have
this special check if the given inode's location objectid is 0, and if it
is, we return the value stored in the VFS' inode i_ino field instead
(which is BTRFS_BTREE_INODE_OBJECTID for the btree inode).

To reduce the code at btrfs_ino(), we can simply set the objectid of the
btree inode to the value BTRFS_BTREE_INODE_OBJECTID. This eliminates the
need to check for the special case of the objectid being zero, with the
side effect of reducing the overall code size and having less code to
execute, as btrfs_ino() is an inline function.

Before:

$ size fs/btrfs/btrfs.ko
   text	   data	    bss	    dec	    hex	filename
1620502	 189240	  29032	1838774	 1c0eb6	fs/btrfs/btrfs.ko

After:

$ size fs/btrfs/btrfs.ko
   text	   data	    bss	    dec	    hex	filename
1617487	 189240	  29032	1835759	 1c02ef	fs/btrfs/btrfs.ko

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00
Fabio M. De Francesco
4cb2e5e8fe btrfs: replace kmap_atomic() with kmap_local_page()
kmap_atomic() is being deprecated in favor of kmap_local_page() where it
is feasible. With kmap_local_page() mappings are per thread, CPU local,
and not globally visible.

The last use of kmap_atomic is in inode.c where the context is atomic [1]
and can be safely replaced by kmap_local_page.

Tested with xfstests on a QEMU + KVM 32-bits VM with 4GB RAM and booting a
kernel with HIGHMEM64GB enabled.

[1] https://lore.kernel.org/linux-btrfs/20220601132545.GM20633@twin.jikos.cz/

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:41 +02:00