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12080 commits

Author SHA1 Message Date
Filipe Manana
50cafe0581 btrfs: fix race between quota disable and relocation
[ Upstream commit 8a4a0b2a3e ]

If we disable quotas while we have a relocation of a metadata block group
that has extents belonging to the quota root, we can cause the relocation
to fail with -ENOENT. This is because relocation builds backref nodes for
extents of the quota root and later needs to walk the backrefs and access
the quota root - however if in between a task disables quotas, it results
in deleting the quota root from the root tree (with btrfs_del_root(),
called from btrfs_quota_disable().

This can be sporadically triggered by test case btrfs/255 from fstests:

  $ ./check btrfs/255
  FSTYP         -- btrfs
  PLATFORM      -- Linux/x86_64 debian0 6.4.0-rc6-btrfs-next-134+ #1 SMP PREEMPT_DYNAMIC Thu Jun 15 11:59:28 WEST 2023
  MKFS_OPTIONS  -- /dev/sdc
  MOUNT_OPTIONS -- /dev/sdc /home/fdmanana/btrfs-tests/scratch_1

  btrfs/255 6s ... _check_dmesg: something found in dmesg (see /home/fdmanana/git/hub/xfstests/results//btrfs/255.dmesg)
  - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/255.out.bad)
#      --- tests/btrfs/255.out	2023-03-02 21:47:53.876609426 +0000
#      +++ /home/fdmanana/git/hub/xfstests/results//btrfs/255.out.bad	2023-06-16 10:20:39.267563212 +0100
#      @@ -1,2 +1,4 @@
#       QA output created by 255
#      +ERROR: error during balancing '/home/fdmanana/btrfs-tests/scratch_1': No such file or directory
#      +There may be more info in syslog - try dmesg | tail
#       Silence is golden
#      ...
      (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/255.out /home/fdmanana/git/hub/xfstests/results//btrfs/255.out.bad'  to see the entire diff)
  Ran: btrfs/255
  Failures: btrfs/255
  Failed 1 of 1 tests

To fix this make the quota disable operation take the cleaner mutex, as
relocation of a block group also takes this mutex. This is also what we
do when deleting a subvolume/snapshot, we take the cleaner mutex in the
cleaner kthread (at cleaner_kthread()) and then we call btrfs_del_root()
at btrfs_drop_snapshot() while under the protection of the cleaner mutex.

Fixes: bed92eae26 ("Btrfs: qgroup implementation and prototypes")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:25:43 +02:00
Christoph Hellwig
693a761758 btrfs: fix fsverify read error handling in end_page_read
[ Upstream commit 2c14f0ffdd ]

Also clear the uptodate bit to make sure the page isn't seen as uptodate
in the page cache if fsverity verification fails.

Fixes: 146054090b ("btrfs: initial fsverity support")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:25:43 +02:00
Christoph Hellwig
c42d836e2e btrfs: factor out a btrfs_verify_page helper
[ Upstream commit ed9ee98ecb ]

Split all the conditionals for the fsverity calls in end_page_read into
a btrfs_verify_page helper to keep the code readable and make additional
refactoring easier.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 2c14f0ffdd ("btrfs: fix fsverify read error handling in end_page_read")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:25:42 +02:00
Christoph Hellwig
0d7c5934f0 btrfs: be a bit more careful when setting mirror_num_ret in btrfs_map_block
[ Upstream commit 4e7de35eb7 ]

The mirror_num_ret is allowed to be NULL, although it has to be set when
smap is set.  Unfortunately that is not a well enough specifiable
invariant for static type checkers, so add a NULL check to make sure they
are fine.

Fixes: 03793cbbc8 ("btrfs: add fast path for single device io in __btrfs_map_block")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:56:54 +02:00
Filipe Manana
951b87d8ba btrfs: abort transaction at update_ref_for_cow() when ref count is zero
[ Upstream commit eced687e22 ]

At update_ref_for_cow() we are calling btrfs_handle_fs_error() if we find
that the extent buffer has an unexpected ref count of zero, however we can
simply use btrfs_abort_transaction(), which achieves the same purposes: to
turn the fs to error state, abort the current transaction and turn the fs
to RO mode as well. Besides that, btrfs_abort_transaction() also prints a
stack trace which makes it more useful.

Also, as this is a very unexpected situation, indicating a serious
corruption/inconsistency, tag the if branch as 'unlikely', set the error
code to -EUCLEAN instead of -EROFS, and log an explicit message.

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:56:46 +02:00
Christoph Hellwig
d40be032ec btrfs: don't check PageError in __extent_writepage
[ Upstream commit 3e92499e3b ]

__extent_writepage currenly sets PageError whenever any error happens,
and the also checks for PageError to decide if to call error handling.
This leads to very unclear responsibility for cleaning up on errors.
In the VM and generic writeback helpers the basic idea is that once
I/O is fired off all error handling responsibility is delegated to the
end I/O handler.  But if that end I/O handler sets the PageError bit,
and the submitter checks it, the bit could in some cases leak into the
submission context for fast enough I/O.

Fix this by simply not checking PageError and just using the local
ret variable to check for submission errors.  This also fundamentally
solves the long problem documented in a comment in __extent_writepage
by never leaking the error bit into the submission context.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:56:46 +02:00
David Sterba
689f5fbd89 btrfs: add xxhash to fast checksum implementations
[ Upstream commit efcfcbc6a3 ]

The implementation of XXHASH is now CPU only but still fast enough to be
considered for the synchronous checksumming, like non-generic crc32c.

A userspace benchmark comparing it to various implementations (patched
hash-speedtest from btrfs-progs):

  Block size:     4096
  Iterations:     1000000
  Implementation: builtin
  Units:          CPU cycles

	NULL-NOP: cycles:     73384294, cycles/i       73
     NULL-MEMCPY: cycles:    228033868, cycles/i      228,    61664.320 MiB/s
      CRC32C-ref: cycles:  24758559416, cycles/i    24758,      567.950 MiB/s
       CRC32C-NI: cycles:   1194350470, cycles/i     1194,    11773.433 MiB/s
  CRC32C-ADLERSW: cycles:   6150186216, cycles/i     6150,     2286.372 MiB/s
  CRC32C-ADLERHW: cycles:    626979180, cycles/i      626,    22427.453 MiB/s
      CRC32C-PCL: cycles:    466746732, cycles/i      466,    30126.699 MiB/s
	  XXHASH: cycles:    860656400, cycles/i      860,    16338.188 MiB/s

Comparing purely software implementation (ref), current outdated
accelerated using crc32q instruction (NI), optimized implementations by
M. Adler (https://stackoverflow.com/questions/17645167/implementing-sse-4-2s-crc32c-in-software/17646775#17646775)
and the best one that was taken from kernel using the PCLMULQDQ
instruction (PCL).

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:56:46 +02:00
Josef Bacik
72efe5d448 btrfs: fix race between balance and cancel/pause
commit b19c98f237 upstream.

Syzbot reported a panic that looks like this:

  assertion failed: fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED, in fs/btrfs/ioctl.c:465
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/messages.c:259!
  RIP: 0010:btrfs_assertfail+0x2c/0x30 fs/btrfs/messages.c:259
  Call Trace:
   <TASK>
   btrfs_exclop_balance fs/btrfs/ioctl.c:465 [inline]
   btrfs_ioctl_balance fs/btrfs/ioctl.c:3564 [inline]
   btrfs_ioctl+0x531e/0x5b30 fs/btrfs/ioctl.c:4632
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:870 [inline]
   __se_sys_ioctl fs/ioctl.c:856 [inline]
   __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x63/0xcd

The reproducer is running a balance and a cancel or pause in parallel.
The way balance finishes is a bit wonky, if we were paused we need to
save the balance_ctl in the fs_info, but clear it otherwise and cleanup.
However we rely on the return values being specific errors, or having a
cancel request or no pause request.  If balance completes and returns 0,
but we have a pause or cancel request we won't do the appropriate
cleanup, and then the next time we try to start a balance we'll trip
this ASSERT.

The error handling is just wrong here, we always want to clean up,
unless we got -ECANCELLED and we set the appropriate pause flag in the
exclusive op.  With this patch the reproducer ran for an hour without
tripping, previously it would trip in less than a few minutes.

Reported-by: syzbot+c0f3acf145cb465426d5@syzkaller.appspotmail.com
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:35 +02:00
Filipe Manana
cca627afb4 btrfs: zoned: fix memory leak after finding block group with super blocks
commit f1a07c2b4e upstream.

At exclude_super_stripes(), if we happen to find a block group that has
super blocks mapped to it and we are on a zoned filesystem, we error out
as this is not supposed to happen, indicating either a bug or maybe some
memory corruption for example. However we are exiting the function without
freeing the memory allocated for the logical address of the super blocks.
Fix this by freeing the logical address.

Fixes: 12659251ca ("btrfs: implement log-structured superblock for ZONED mode")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:34 +02:00
Filipe Manana
40150056dc btrfs: fix double iput() on inode after an error during orphan cleanup
commit b777d279ff upstream.

At btrfs_orphan_cleanup(), if we were able to find the inode, we do an
iput() on the inode, then if btrfs_drop_verity_items() succeeds and then
either btrfs_start_transaction() or btrfs_del_orphan_item() fail, we do
another iput() in the respective error paths, resulting in an extra iput()
on the inode.

Fix this by setting inode to NULL after the first iput(), as iput()
ignores a NULL inode pointer argument.

Fixes: a13bb2c038 ("btrfs: add missing iputs on orphan cleanup failure")
CC: stable@vger.kernel.org # 6.4
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:34 +02:00
Josef Bacik
a5880e69cf btrfs: set_page_extent_mapped after read_folio in btrfs_cont_expand
commit 17b17fcd6d upstream.

While trying to get the subpage blocksize tests running, I hit the
following panic on generic/476

  assertion failed: PagePrivate(page) && page->private, in fs/btrfs/subpage.c:229
  kernel BUG at fs/btrfs/subpage.c:229!
  Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
  CPU: 1 PID: 1453 Comm: fsstress Not tainted 6.4.0-rc7+ #12
  Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20230301gitf80f052277c8-26.fc38 03/01/2023
  pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
  pc : btrfs_subpage_assert+0xbc/0xf0
  lr : btrfs_subpage_assert+0xbc/0xf0
  Call trace:
   btrfs_subpage_assert+0xbc/0xf0
   btrfs_subpage_clear_checked+0x38/0xc0
   btrfs_page_clear_checked+0x48/0x98
   btrfs_truncate_block+0x5d0/0x6a8
   btrfs_cont_expand+0x5c/0x528
   btrfs_write_check.isra.0+0xf8/0x150
   btrfs_buffered_write+0xb4/0x760
   btrfs_do_write_iter+0x2f8/0x4b0
   btrfs_file_write_iter+0x1c/0x30
   do_iter_readv_writev+0xc8/0x158
   do_iter_write+0x9c/0x210
   vfs_iter_write+0x24/0x40
   iter_file_splice_write+0x224/0x390
   direct_splice_actor+0x38/0x68
   splice_direct_to_actor+0x12c/0x260
   do_splice_direct+0x90/0xe8
   generic_copy_file_range+0x50/0x90
   vfs_copy_file_range+0x29c/0x470
   __arm64_sys_copy_file_range+0xcc/0x498
   invoke_syscall.constprop.0+0x80/0xd8
   do_el0_svc+0x6c/0x168
   el0_svc+0x50/0x1b0
   el0t_64_sync_handler+0x114/0x120
   el0t_64_sync+0x194/0x198

This happens because during btrfs_cont_expand we'll get a page, set it
as mapped, and if it's not Uptodate we'll read it.  However between the
read and re-locking the page we could have called release_folio() on the
page, but left the page in the file mapping.  release_folio() can clear
the page private, and thus further down we blow up when we go to modify
the subpage bits.

Fix this by putting the set_page_extent_mapped() after the read.  This
is safe because read_folio() will call set_page_extent_mapped() before
it does the read, and then if we clear page private but leave it on the
mapping we're completely safe re-setting set_page_extent_mapped().  With
this patch I can now run generic/476 without panicing.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:34 +02:00
Qu Wenruo
a981a8b5d3 btrfs: raid56: always verify the P/Q contents for scrub
commit 486c737f7f upstream.

[REGRESSION]
Commit 75b4703329 ("btrfs: raid56: migrate recovery and scrub recovery
path to use error_bitmap") changed the behavior of scrub_rbio().

Initially if we have no error reading the raid bio, we will assign
@need_check to true, then finish_parity_scrub() would later verify the
content of P/Q stripes before writeback.

But after that commit we never verify the content of P/Q stripes and
just writeback them.

This can lead to unrepaired P/Q stripes during scrub, or already
corrupted P/Q copied to the dev-replace target.

[FIX]
The situation is more complex than the regression, in fact the initial
behavior is not 100% correct either.

If we have the following rare case, it can still lead to the same
problem using the old behavior:

		0	16K	32K	48K	64K
	Data 1:	|IIIIIII|                       |
	Data 2:	|				|
	Parity:	|	|CCCCCCC|		|

Where "I" means IO error, "C" means corruption.

In the above case, we're scrubbing the parity stripe, then read out all
the contents of Data 1, Data 2, Parity stripes.

But found IO error in Data 1, which leads to rebuild using Data 2 and
Parity and got the correct data.

In that case, we would not verify if the Parity is correct for range
[16K, 32K).

So here we have to always verify the content of Parity no matter if we
did recovery or not.

This patch would remove the @need_check parameter of
finish_parity_scrub() completely, and would always do the P/Q
verification before writeback.

Fixes: 75b4703329 ("btrfs: raid56: migrate recovery and scrub recovery path to use error_bitmap")
CC: stable@vger.kernel.org # 6.2+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:34 +02:00
Filipe Manana
62dd82bc7a btrfs: fix warning when putting transaction with qgroups enabled after abort
commit aa84ce8a78 upstream.

If we have a transaction abort with qgroups enabled we get a warning
triggered when doing the final put on the transaction, like this:

  [552.6789] ------------[ cut here ]------------
  [552.6815] WARNING: CPU: 4 PID: 81745 at fs/btrfs/transaction.c:144 btrfs_put_transaction+0x123/0x130 [btrfs]
  [552.6817] Modules linked in: btrfs blake2b_generic xor (...)
  [552.6819] CPU: 4 PID: 81745 Comm: btrfs-transacti Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1
  [552.6819] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [552.6819] RIP: 0010:btrfs_put_transaction+0x123/0x130 [btrfs]
  [552.6821] Code: bd a0 01 00 (...)
  [552.6821] RSP: 0018:ffffa168c0527e28 EFLAGS: 00010286
  [552.6821] RAX: ffff936042caed00 RBX: ffff93604a3eb448 RCX: 0000000000000000
  [552.6821] RDX: ffff93606421b028 RSI: ffffffff92ff0878 RDI: ffff93606421b010
  [552.6821] RBP: ffff93606421b000 R08: 0000000000000000 R09: ffffa168c0d07c20
  [552.6821] R10: 0000000000000000 R11: ffff93608dc52950 R12: ffffa168c0527e70
  [552.6821] R13: ffff93606421b000 R14: ffff93604a3eb420 R15: ffff93606421b028
  [552.6821] FS:  0000000000000000(0000) GS:ffff93675fb00000(0000) knlGS:0000000000000000
  [552.6821] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [552.6821] CR2: 0000558ad262b000 CR3: 000000014feda005 CR4: 0000000000370ee0
  [552.6822] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [552.6822] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [552.6822] Call Trace:
  [552.6822]  <TASK>
  [552.6822]  ? __warn+0x80/0x130
  [552.6822]  ? btrfs_put_transaction+0x123/0x130 [btrfs]
  [552.6824]  ? report_bug+0x1f4/0x200
  [552.6824]  ? handle_bug+0x42/0x70
  [552.6824]  ? exc_invalid_op+0x14/0x70
  [552.6824]  ? asm_exc_invalid_op+0x16/0x20
  [552.6824]  ? btrfs_put_transaction+0x123/0x130 [btrfs]
  [552.6826]  btrfs_cleanup_transaction+0xe7/0x5e0 [btrfs]
  [552.6828]  ? _raw_spin_unlock_irqrestore+0x23/0x40
  [552.6828]  ? try_to_wake_up+0x94/0x5e0
  [552.6828]  ? __pfx_process_timeout+0x10/0x10
  [552.6828]  transaction_kthread+0x103/0x1d0 [btrfs]
  [552.6830]  ? __pfx_transaction_kthread+0x10/0x10 [btrfs]
  [552.6832]  kthread+0xee/0x120
  [552.6832]  ? __pfx_kthread+0x10/0x10
  [552.6832]  ret_from_fork+0x29/0x50
  [552.6832]  </TASK>
  [552.6832] ---[ end trace 0000000000000000 ]---

This corresponds to this line of code:

  void btrfs_put_transaction(struct btrfs_transaction *transaction)
  {
      (...)
          WARN_ON(!RB_EMPTY_ROOT(
                          &transaction->delayed_refs.dirty_extent_root));
      (...)
  }

The warning happens because btrfs_qgroup_destroy_extent_records(), called
in the transaction abort path, we free all entries from the rbtree
"dirty_extent_root" with rbtree_postorder_for_each_entry_safe(), but we
don't actually empty the rbtree - it's still pointing to nodes that were
freed.

So set the rbtree's root node to NULL to avoid this warning (assign
RB_ROOT).

Fixes: 81f7eb00ff ("btrfs: destroy qgroup extent records on transaction abort")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:33 +02:00
Filipe Manana
a21a43e433 btrfs: fix iput() on error pointer after error during orphan cleanup
commit cbaee87f2e upstream.

At btrfs_orphan_cleanup(), if we can't find an inode (btrfs_iget() returns
an -ENOENT error pointer), we proceed with 'ret' set to -ENOENT and the
inode pointer set to ERR_PTR(-ENOENT). Later when we proceed to the body
of the following if statement:

    if (ret == -ENOENT || inode->i_nlink) {
        (...)
        trans = btrfs_start_transaction(root, 1);
        if (IS_ERR(trans)) {
            ret = PTR_ERR(trans);
            iput(inode);
            goto out;
        }
        (...)
        ret = btrfs_del_orphan_item(trans, root,
                                    found_key.objectid);
        btrfs_end_transaction(trans);
        if (ret) {
            iput(inode);
            goto out;
        }
        continue;
    }

If we get an error from btrfs_start_transaction() or from the call to
btrfs_del_orphan_item() we end calling iput() against an inode pointer
that has a value of ERR_PTR(-ENOENT), resulting in a crash with the
following trace:

  [876.667] BUG: kernel NULL pointer dereference, address: 0000000000000096
  [876.667] #PF: supervisor read access in kernel mode
  [876.667] #PF: error_code(0x0000) - not-present page
  [876.667] PGD 0 P4D 0
  [876.668] Oops: 0000 [#1] PREEMPT SMP PTI
  [876.668] CPU: 0 PID: 2356187 Comm: mount Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1
  [876.668] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
  [876.668] RIP: 0010:iput+0xa/0x20
  [876.668] Code: ff ff ff 66 (...)
  [876.669] RSP: 0018:ffffafa9c0c9f9d0 EFLAGS: 00010282
  [876.669] RAX: ffffffffffffffe4 RBX: 000000000009453b RCX: 0000000000000000
  [876.669] RDX: 0000000000000001 RSI: ffffafa9c0c9f930 RDI: fffffffffffffffe
  [876.669] RBP: ffff95c612f3b800 R08: 0000000000000001 R09: ffffffffffffffe4
  [876.670] R10: 00018f2a71010000 R11: 000000000ead96e3 R12: ffff95cb7d6909a0
  [876.670] R13: fffffffffffffffe R14: ffff95c60f477000 R15: 00000000ffffffe4
  [876.670] FS:  00007f5fbe30a840(0000) GS:ffff95ccdfa00000(0000) knlGS:0000000000000000
  [876.670] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [876.671] CR2: 0000000000000096 CR3: 000000055e9f6004 CR4: 0000000000370ef0
  [876.671] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [876.671] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [876.672] Call Trace:
  [876.744]  <TASK>
  [876.744]  ? __die_body+0x1b/0x60
  [876.744]  ? page_fault_oops+0x15d/0x450
  [876.745]  ? __kmem_cache_alloc_node+0x47/0x410
  [876.745]  ? do_user_addr_fault+0x65/0x8a0
  [876.745]  ? exc_page_fault+0x74/0x170
  [876.746]  ? asm_exc_page_fault+0x22/0x30
  [876.746]  ? iput+0xa/0x20
  [876.746]  btrfs_orphan_cleanup+0x221/0x330 [btrfs]
  [876.746]  btrfs_lookup_dentry+0x58f/0x5f0 [btrfs]
  [876.747]  btrfs_lookup+0xe/0x30 [btrfs]
  [876.747]  __lookup_slow+0x82/0x130
  [876.785]  walk_component+0xe5/0x160
  [876.786]  path_lookupat.isra.0+0x6e/0x150
  [876.786]  filename_lookup+0xcf/0x1a0
  [876.786]  ? mod_objcg_state+0xd2/0x360
  [876.786]  ? obj_cgroup_charge+0xf5/0x110
  [876.787]  ? should_failslab+0xa/0x20
  [876.787]  ? kmem_cache_alloc+0x47/0x450
  [876.787]  vfs_path_lookup+0x51/0x90
  [876.788]  mount_subtree+0x8d/0x130
  [876.788]  btrfs_mount+0x149/0x410 [btrfs]
  [876.788]  ? __kmem_cache_alloc_node+0x47/0x410
  [876.788]  ? vfs_parse_fs_param+0xc0/0x110
  [876.789]  legacy_get_tree+0x24/0x50
  [876.834]  vfs_get_tree+0x22/0xd0
  [876.852]  path_mount+0x2d8/0x9c0
  [876.852]  do_mount+0x79/0x90
  [876.852]  __x64_sys_mount+0x8e/0xd0
  [876.853]  do_syscall_64+0x38/0x90
  [876.899]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [876.958] RIP: 0033:0x7f5fbe50b76a
  [876.959] Code: 48 8b 0d a9 (...)
  [876.959] RSP: 002b:00007fff01925798 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
  [876.959] RAX: ffffffffffffffda RBX: 00007f5fbe694264 RCX: 00007f5fbe50b76a
  [876.960] RDX: 0000561bde6c8720 RSI: 0000561bde6bdec0 RDI: 0000561bde6c31a0
  [876.960] RBP: 0000561bde6bdc70 R08: 0000000000000000 R09: 0000000000000001
  [876.960] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  [876.960] R13: 0000561bde6c31a0 R14: 0000561bde6c8720 R15: 0000561bde6bdc70
  [876.960]  </TASK>

So fix this by setting 'inode' to NULL whenever we get an error from
btrfs_iget(), and to make the code simpler, stop testing for 'ret' being
-ENOENT to check if we have an inode - instead test for 'inode' being NULL
or not. Having a NULL 'inode' prevents any iput() call from crashing, as
iput() ignores NULL inode pointers. Also, stop testing for a NULL return
value from btrfs_iget() with PTR_ERR_OR_ZERO(), because btrfs_iget() never
returns NULL - in case an inode is not found, it returns ERR_PTR(-ENOENT),
and in case of memory allocation failure, it returns ERR_PTR(-ENOMEM).
We also don't need the extra iput() calls on the error branches for the
btrfs_start_transaction() and btrfs_del_orphan_item() calls, as we have
already called iput() before, so remove them.

Fixes: a13bb2c038 ("btrfs: add missing iputs on orphan cleanup failure")
CC: stable@vger.kernel.org # 6.4
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:33 +02:00
Filipe Manana
82270e7f28 btrfs: do not BUG_ON() on tree mod log failure at __btrfs_cow_block()
commit 40b0a74938 upstream.

At __btrfs_cow_block(), instead of doing a BUG_ON() in case we fail to
record a tree mod log root insertion operation, do a transaction abort
instead. There's really no need for the BUG_ON(), we can properly
release all resources in this context and turn the filesystem to RO mode
and in an error state instead.

CC: stable@vger.kernel.org # 5.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:57 +02:00
Filipe Manana
796eb12aa5 btrfs: fix extent buffer leak after tree mod log failure at split_node()
commit ede600e497 upstream.

At split_node(), if we fail to log the tree mod log copy operation, we
return without unlocking the split extent buffer we just allocated and
without decrementing the reference we own on it. Fix this by unlocking
it and decrementing the ref count before returning.

Fixes: 5de865eebb ("Btrfs: fix tree mod logging")
CC: stable@vger.kernel.org # 5.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:57 +02:00
Filipe Manana
6df630a1e3 btrfs: add missing error handling when logging operation while COWing extent buffer
commit d09c51521f upstream.

When COWing an extent buffer that is not the root node, we need to log in
the tree mod log that we replaced a pointer in the parent node, otherwise
a tree mod log user doing a search on the b+tree can return incorrect
results (that miss something). We are doing the call to
btrfs_tree_mod_log_insert_key() but we totally ignore its return value.

So fix this by adding the missing error handling, resulting in a
transaction abort and freeing the COWed extent buffer.

Fixes: f230475e62 ("Btrfs: put all block modifications into the tree mod log")
CC: stable@vger.kernel.org # 5.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:57 +02:00
Filipe Manana
a5cdc4012e btrfs: fix race when deleting quota root from the dirty cow roots list
commit b31cb5a6eb upstream.

When disabling quotas we are deleting the quota root from the list
fs_info->dirty_cowonly_roots without taking the lock that protects it,
which is struct btrfs_fs_info::trans_lock. This unsynchronized list
manipulation may cause chaos if there's another concurrent manipulation
of this list, such as when adding a root to it with
ctree.c:add_root_to_dirty_list().

This can result in all sorts of weird failures caused by a race, such as
the following crash:

  [337571.278245] general protection fault, probably for non-canonical address 0xdead000000000108: 0000 [#1] PREEMPT SMP PTI
  [337571.278933] CPU: 1 PID: 115447 Comm: btrfs Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1
  [337571.279153] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [337571.279572] RIP: 0010:commit_cowonly_roots+0x11f/0x250 [btrfs]
  [337571.279928] Code: 85 38 06 00 (...)
  [337571.280363] RSP: 0018:ffff9f63446efba0 EFLAGS: 00010206
  [337571.280582] RAX: ffff942d98ec2638 RBX: ffff9430b82b4c30 RCX: 0000000449e1c000
  [337571.280798] RDX: dead000000000100 RSI: ffff9430021e4900 RDI: 0000000000036070
  [337571.281015] RBP: ffff942d98ec2000 R08: ffff942d98ec2000 R09: 000000000000015b
  [337571.281254] R10: 0000000000000009 R11: 0000000000000001 R12: ffff942fe8fbf600
  [337571.281476] R13: ffff942dabe23040 R14: ffff942dabe20800 R15: ffff942d92cf3b48
  [337571.281723] FS:  00007f478adb7340(0000) GS:ffff94349fa40000(0000) knlGS:0000000000000000
  [337571.281950] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [337571.282184] CR2: 00007f478ab9a3d5 CR3: 000000001e02c001 CR4: 0000000000370ee0
  [337571.282416] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [337571.282647] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [337571.282874] Call Trace:
  [337571.283101]  <TASK>
  [337571.283327]  ? __die_body+0x1b/0x60
  [337571.283570]  ? die_addr+0x39/0x60
  [337571.283796]  ? exc_general_protection+0x22e/0x430
  [337571.284022]  ? asm_exc_general_protection+0x22/0x30
  [337571.284251]  ? commit_cowonly_roots+0x11f/0x250 [btrfs]
  [337571.284531]  btrfs_commit_transaction+0x42e/0xf90 [btrfs]
  [337571.284803]  ? _raw_spin_unlock+0x15/0x30
  [337571.285031]  ? release_extent_buffer+0x103/0x130 [btrfs]
  [337571.285305]  reset_balance_state+0x152/0x1b0 [btrfs]
  [337571.285578]  btrfs_balance+0xa50/0x11e0 [btrfs]
  [337571.285864]  ? __kmem_cache_alloc_node+0x14a/0x410
  [337571.286086]  btrfs_ioctl+0x249a/0x3320 [btrfs]
  [337571.286358]  ? mod_objcg_state+0xd2/0x360
  [337571.286577]  ? refill_obj_stock+0xb0/0x160
  [337571.286798]  ? seq_release+0x25/0x30
  [337571.287016]  ? __rseq_handle_notify_resume+0x3ba/0x4b0
  [337571.287235]  ? percpu_counter_add_batch+0x2e/0xa0
  [337571.287455]  ? __x64_sys_ioctl+0x88/0xc0
  [337571.287675]  __x64_sys_ioctl+0x88/0xc0
  [337571.287901]  do_syscall_64+0x38/0x90
  [337571.288126]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [337571.288352] RIP: 0033:0x7f478aaffe9b

So fix this by locking struct btrfs_fs_info::trans_lock before deleting
the quota root from that list.

Fixes: bed92eae26 ("Btrfs: qgroup implementation and prototypes")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:57 +02:00
Naohiro Aota
6c65062f66 btrfs: reinsert BGs failed to reclaim
commit 7e27180994 upstream.

The reclaim process can temporarily fail. For example, if the space is
getting tight, it fails to make the block group read-only. If there are no
further writes on that block group, the block group will never get back to
the reclaim list, and the BG never gets reclaimed. In a certain workload,
we can leave many such block groups never reclaimed.

So, let's get it back to the list and give it a chance to be reclaimed.

Fixes: 18bb8bbf13 ("btrfs: zoned: automatically reclaim zones")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:57 +02:00
David Sterba
7b063701b5 btrfs: add block-group tree to lockdep classes
commit 1a1b0e729d upstream.

The block group tree was not present among the lockdep classes. We could
get potentially lockdep warnings but so far none has been seen, also
because block-group-tree is a relatively new feature.

CC: stable@vger.kernel.org # 6.1+
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:57 +02:00
Naohiro Aota
f61029274c btrfs: bail out reclaim process if filesystem is read-only
commit 93463ff7b5 upstream.

When a filesystem is read-only, we cannot reclaim a block group as it
cannot rewrite the data. Just bail out in that case.

Note that it can drop block groups in this case. As we did
sb_start_write(), read-only filesystem means we got a fatal error and
forced read-only. There is no chance to reclaim them again.

Fixes: 18bb8bbf13 ("btrfs: zoned: automatically reclaim zones")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:56 +02:00
Naohiro Aota
9d9586ef1a btrfs: delete unused BGs while reclaiming BGs
commit 3ed01616ba upstream.

The reclaiming process only starts after the filesystem volumes are
allocated to a certain level (75% by default). Thus, the list of
reclaiming target block groups can build up so huge at the time the
reclaim process kicks in. On a test run, there were over 1000 BGs in the
reclaim list.

As the reclaim involves rewriting the data, it takes really long time to
reclaim the BGs. While the reclaim is running, btrfs_delete_unused_bgs()
won't proceed because the reclaim side is holding
fs_info->reclaim_bgs_lock. As a result, we will have a large number of
unused BGs kept in the unused list. On my test run, I got 1057 unused BGs.

Since deleting a block group is relatively easy and fast work, we can call
btrfs_delete_unused_bgs() while it reclaims BGs, to avoid building up
unused BGs.

Fixes: 18bb8bbf13 ("btrfs: zoned: automatically reclaim zones")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:56 +02:00
Boris Burkov
987cf64973 btrfs: warn on invalid slot in tree mod log rewind
commit 95c8e349d8 upstream.

The way that tree mod log tracks the ultimate length of the eb, the
variable 'n', eventually turns up the correct value, but at intermediate
steps during the rewind, n can be inaccurate as a representation of the
end of the eb. For example, it doesn't get updated on move rewinds, and
it does get updated for add/remove in the middle of the eb.

To detect cases with invalid moves, introduce a separate variable called
max_slot which tries to track the maximum valid slot in the rewind eb.
We can then warn if we do a move whose src range goes beyond the max
valid slot.

There is a commented caveat that it is possible to have this value be an
overestimate due to the challenge of properly handling 'add' operations
in the middle of the eb, but in practice it doesn't cause enough of a
problem to throw out the max idea in favor of tracking every valid slot.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:56 +02:00
Boris Burkov
11f14402fe btrfs: insert tree mod log move in push_node_left
commit 5cead5422a upstream.

There is a fairly unlikely race condition in tree mod log rewind that
can result in a kernel panic which has the following trace:

  [530.569] BTRFS critical (device sda3): unable to find logical 0 length 4096
  [530.585] BTRFS critical (device sda3): unable to find logical 0 length 4096
  [530.602] BUG: kernel NULL pointer dereference, address: 0000000000000002
  [530.618] #PF: supervisor read access in kernel mode
  [530.629] #PF: error_code(0x0000) - not-present page
  [530.641] PGD 0 P4D 0
  [530.647] Oops: 0000 [#1] SMP
  [530.654] CPU: 30 PID: 398973 Comm: below Kdump: loaded Tainted: G S         O  K   5.12.0-0_fbk13_clang_7455_gb24de3bdb045 #1
  [530.680] Hardware name: Quanta Mono Lake-M.2 SATA 1HY9U9Z001G/Mono Lake-M.2 SATA, BIOS F20_3A15 08/16/2017
  [530.703] RIP: 0010:__btrfs_map_block+0xaa/0xd00
  [530.755] RSP: 0018:ffffc9002c2f7600 EFLAGS: 00010246
  [530.767] RAX: ffffffffffffffea RBX: ffff888292e41000 RCX: f2702d8b8be15100
  [530.784] RDX: ffff88885fda6fb8 RSI: ffff88885fd973c8 RDI: ffff88885fd973c8
  [530.800] RBP: ffff888292e410d0 R08: ffffffff82fd7fd0 R09: 00000000fffeffff
  [530.816] R10: ffffffff82e57fd0 R11: ffffffff82e57d70 R12: 0000000000000000
  [530.832] R13: 0000000000001000 R14: 0000000000001000 R15: ffffc9002c2f76f0
  [530.848] FS:  00007f38d64af000(0000) GS:ffff88885fd80000(0000) knlGS:0000000000000000
  [530.866] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [530.880] CR2: 0000000000000002 CR3: 00000002b6770004 CR4: 00000000003706e0
  [530.896] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [530.912] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [530.928] Call Trace:
  [530.934]  ? btrfs_printk+0x13b/0x18c
  [530.943]  ? btrfs_bio_counter_inc_blocked+0x3d/0x130
  [530.955]  btrfs_map_bio+0x75/0x330
  [530.963]  ? kmem_cache_alloc+0x12a/0x2d0
  [530.973]  ? btrfs_submit_metadata_bio+0x63/0x100
  [530.984]  btrfs_submit_metadata_bio+0xa4/0x100
  [530.995]  submit_extent_page+0x30f/0x360
  [531.004]  read_extent_buffer_pages+0x49e/0x6d0
  [531.015]  ? submit_extent_page+0x360/0x360
  [531.025]  btree_read_extent_buffer_pages+0x5f/0x150
  [531.037]  read_tree_block+0x37/0x60
  [531.046]  read_block_for_search+0x18b/0x410
  [531.056]  btrfs_search_old_slot+0x198/0x2f0
  [531.066]  resolve_indirect_ref+0xfe/0x6f0
  [531.076]  ? ulist_alloc+0x31/0x60
  [531.084]  ? kmem_cache_alloc_trace+0x12e/0x2b0
  [531.095]  find_parent_nodes+0x720/0x1830
  [531.105]  ? ulist_alloc+0x10/0x60
  [531.113]  iterate_extent_inodes+0xea/0x370
  [531.123]  ? btrfs_previous_extent_item+0x8f/0x110
  [531.134]  ? btrfs_search_path_in_tree+0x240/0x240
  [531.146]  iterate_inodes_from_logical+0x98/0xd0
  [531.157]  ? btrfs_search_path_in_tree+0x240/0x240
  [531.168]  btrfs_ioctl_logical_to_ino+0xd9/0x180
  [531.179]  btrfs_ioctl+0xe2/0x2eb0

This occurs when logical inode resolution takes a tree mod log sequence
number, and then while backref walking hits a rewind on a busy node
which has the following sequence of tree mod log operations (numbers
filled in from a specific example, but they are somewhat arbitrary)

  REMOVE_WHILE_FREEING slot 532
  REMOVE_WHILE_FREEING slot 531
  REMOVE_WHILE_FREEING slot 530
  ...
  REMOVE_WHILE_FREEING slot 0
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0
  ADD slot 455
  ADD slot 454
  ADD slot 453
  ...
  ADD slot 0
  MOVE src slot 0 -> dst slot 456 nritems 533
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0

When this sequence gets applied via btrfs_tree_mod_log_rewind, it
allocates a fresh rewind eb, and first inserts the correct key info for
the 533 elements, then overwrites the first 456 of them, then decrements
the count by 456 via the add ops, then rewinds the move by doing a
memmove from 456:988->0:532. We have never written anything past 532, so
that memmove writes garbage into the 0:532 range. In practice, this
results in a lot of fully 0 keys. The rewind then puts valid keys into
slots 0:455 with the last removes, but 456:532 are still invalid.

When search_old_slot uses this eb, if it uses one of those invalid
slots, it can then read the extent buffer and issue a bio for offset 0
which ultimately panics looking up extent mappings.

This bad tree mod log sequence gets generated when the node balancing
code happens to do a balance_node_right followed by a push_node_left
while logging in the tree mod log. Illustrated for ebs L and R (left and
right):

	L                 R
  start:
  [XXX|YYY|...]      [ZZZ|...|...]
  balance_node_right:
  [XXX|YYY|...]      [...|ZZZ|...] move Z to make room for Y
  [XXX|...|...]      [YYY|ZZZ|...] copy Y from L to R
  push_node_left:
  [XXX|YYY|...]      [...|ZZZ|...] copy Y from R to L
  [XXX|YYY|...]      [ZZZ|...|...] move Z into emptied space (NOT LOGGED!)

This is because balance_node_right logs a move, but push_node_left
explicitly doesn't. That is because logging the move would remove the
overwritten src < dst range in the right eb, which was already logged
when we called btrfs_tree_mod_log_eb_copy. The correct sequence would
include a move from 456:988 to 0:532 after remove 0:455 and before
removing 0:532. Reversing that sequence would entail creating keys for
0:532, then moving those keys out to 456:988, then creating more keys
for 0:455.

i.e.,

  REMOVE_WHILE_FREEING slot 532
  REMOVE_WHILE_FREEING slot 531
  REMOVE_WHILE_FREEING slot 530
  ...
  REMOVE_WHILE_FREEING slot 0
  MOVE src slot 456 -> dst slot 0 nritems 533
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0
  ADD slot 455
  ADD slot 454
  ADD slot 453
  ...
  ADD slot 0
  MOVE src slot 0 -> dst slot 456 nritems 533
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0

Fix this to log the move but avoid the double remove by putting all the
logging logic in btrfs_tree_mod_log_eb_copy which has enough information
to detect these cases and properly log moves, removes, and adds. Leave
btrfs_tree_mod_log_insert_move to handle insert_ptr and delete_ptr's
tree mod logging.

(Un)fortunately, this is quite difficult to reproduce, and I was only
able to reproduce it by adding sleeps in btrfs_search_old_slot that
would encourage more log rewinding during ino_to_logical ioctls. I was
able to hit the warning in the previous patch in the series without the
fix quite quickly, but not after this patch.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:56 +02:00
Christoph Hellwig
1ea89213cd btrfs: fix dirty_metadata_bytes for redirtied buffers
commit f18cc97845 upstream.

dirty_metadata_bytes is decremented in both places that clear the dirty
bit in a buffer, but only incremented in btrfs_mark_buffer_dirty, which
means that a buffer that is redirtied using btrfs_redirty_list_add won't
be added to dirty_metadata_bytes, but it will be subtracted when written
out, leading an inconsistency in the counter.

Move the dirty_metadata_bytes from btrfs_mark_buffer_dirty into
set_extent_buffer_dirty to also account for the redirty case, and remove
the now unused set_extent_buffer_dirty return value.

Fixes: d3575156f6 ("btrfs: zoned: redirty released extent buffers")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:56 +02:00
Matt Corallo
1b532748ba btrfs: add handling for RAID1C23/DUP to btrfs_reduce_alloc_profile
commit 160fe8f6fd upstream.

Callers of `btrfs_reduce_alloc_profile` expect it to return exactly
one allocation profile flag, and failing to do so may ultimately
result in a WARN_ON and remount-ro when allocating new blocks, like
the below transaction abort on 6.1.

`btrfs_reduce_alloc_profile` has two ways of determining the profile,
first it checks if a conversion balance is currently running and
uses the profile we're converting to. If no balance is currently
running, it returns the max-redundancy profile which at least one
block in the selected block group has.

This works by simply checking each known allocation profile bit in
redundancy order. However, `btrfs_reduce_alloc_profile` has not been
updated as new flags have been added - first with the `DUP` profile
and later with the RAID1C34 profiles.

Because of the way it checks, if we have blocks with different
profiles and at least one is known, that profile will be selected.
However, if none are known we may return a flag set with multiple
allocation profiles set.

This is currently only possible when a balance from one of the three
unhandled profiles to another of the unhandled profiles is canceled
after allocating at least one block using the new profile.

In that case, a transaction abort like the below will occur and the
filesystem will need to be mounted with -o skip_balance to get it
mounted rw again (but the balance cannot be resumed without a
similar abort).

  [770.648] ------------[ cut here ]------------
  [770.648] BTRFS: Transaction aborted (error -22)
  [770.648] WARNING: CPU: 43 PID: 1159593 at fs/btrfs/extent-tree.c:4122 find_free_extent+0x1d94/0x1e00 [btrfs]
  [770.648] CPU: 43 PID: 1159593 Comm: btrfs Tainted: G        W 6.1.0-0.deb11.7-powerpc64le #1  Debian 6.1.20-2~bpo11+1a~test
  [770.648] Hardware name: T2P9D01 REV 1.00 POWER9 0x4e1202 opal:skiboot-bc106a0 PowerNV
  [770.648] NIP:  c00800000f6784fc LR: c00800000f6784f8 CTR: c000000000d746c0
  [770.648] REGS: c000200089afe9a0 TRAP: 0700   Tainted: G        W (6.1.0-0.deb11.7-powerpc64le Debian 6.1.20-2~bpo11+1a~test)
  [770.648] MSR:  9000000002029033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE>  CR: 28848282  XER: 20040000
  [770.648] CFAR: c000000000135110 IRQMASK: 0
	    GPR00: c00800000f6784f8 c000200089afec40 c00800000f7ea800 0000000000000026
	    GPR04: 00000001004820c2 c000200089afea00 c000200089afe9f8 0000000000000027
	    GPR08: c000200ffbfe7f98 c000000002127f90 ffffffffffffffd8 0000000026d6a6e8
	    GPR12: 0000000028848282 c000200fff7f3800 5deadbeef0000122 c00000002269d000
	    GPR16: c0002008c7797c40 c000200089afef17 0000000000000000 0000000000000000
	    GPR20: 0000000000000000 0000000000000001 c000200008bc5a98 0000000000000001
	    GPR24: 0000000000000000 c0000003c73088d0 c000200089afef17 c000000016d3a800
	    GPR28: c0000003c7308800 c00000002269d000 ffffffffffffffea 0000000000000001
  [770.648] NIP [c00800000f6784fc] find_free_extent+0x1d94/0x1e00 [btrfs]
  [770.648] LR [c00800000f6784f8] find_free_extent+0x1d90/0x1e00 [btrfs]
  [770.648] Call Trace:
  [770.648] [c000200089afec40] [c00800000f6784f8] find_free_extent+0x1d90/0x1e00 [btrfs] (unreliable)
  [770.648] [c000200089afed30] [c00800000f681398] btrfs_reserve_extent+0x1a0/0x2f0 [btrfs]
  [770.648] [c000200089afeea0] [c00800000f681bf0] btrfs_alloc_tree_block+0x108/0x670 [btrfs]
  [770.648] [c000200089afeff0] [c00800000f66bd68] __btrfs_cow_block+0x170/0x850 [btrfs]
  [770.648] [c000200089aff100] [c00800000f66c58c] btrfs_cow_block+0x144/0x288 [btrfs]
  [770.648] [c000200089aff1b0] [c00800000f67113c] btrfs_search_slot+0x6b4/0xcb0 [btrfs]
  [770.648] [c000200089aff2a0] [c00800000f679f60] lookup_inline_extent_backref+0x128/0x7c0 [btrfs]
  [770.648] [c000200089aff3b0] [c00800000f67b338] lookup_extent_backref+0x70/0x190 [btrfs]
  [770.648] [c000200089aff470] [c00800000f67b54c] __btrfs_free_extent+0xf4/0x1490 [btrfs]
  [770.648] [c000200089aff5a0] [c00800000f67d770] __btrfs_run_delayed_refs+0x328/0x1530 [btrfs]
  [770.648] [c000200089aff740] [c00800000f67ea2c] btrfs_run_delayed_refs+0xb4/0x3e0 [btrfs]
  [770.648] [c000200089aff800] [c00800000f699aa4] btrfs_commit_transaction+0x8c/0x12b0 [btrfs]
  [770.648] [c000200089aff8f0] [c00800000f6dc628] reset_balance_state+0x1c0/0x290 [btrfs]
  [770.648] [c000200089aff9a0] [c00800000f6e2f7c] btrfs_balance+0x1164/0x1500 [btrfs]
  [770.648] [c000200089affb40] [c00800000f6f8e4c] btrfs_ioctl+0x2b54/0x3100 [btrfs]
  [770.648] [c000200089affc80] [c00000000053be14] sys_ioctl+0x794/0x1310
  [770.648] [c000200089affd70] [c00000000002af98] system_call_exception+0x138/0x250
  [770.648] [c000200089affe10] [c00000000000c654] system_call_common+0xf4/0x258
  [770.648] --- interrupt: c00 at 0x7fff94126800
  [770.648] NIP:  00007fff94126800 LR: 0000000107e0b594 CTR: 0000000000000000
  [770.648] REGS: c000200089affe80 TRAP: 0c00   Tainted: G        W (6.1.0-0.deb11.7-powerpc64le Debian 6.1.20-2~bpo11+1a~test)
  [770.648] MSR:  900000000000d033 <SF,HV,EE,PR,ME,IR,DR,RI,LE>  CR: 24002848  XER: 00000000
  [770.648] IRQMASK: 0
	    GPR00: 0000000000000036 00007fffc9439da0 00007fff94217100 0000000000000003
	    GPR04: 00000000c4009420 00007fffc9439ee8 0000000000000000 0000000000000000
	    GPR08: 00000000803c7416 0000000000000000 0000000000000000 0000000000000000
	    GPR12: 0000000000000000 00007fff9467d120 0000000107e64c9c 0000000107e64d0a
	    GPR16: 0000000107e64d06 0000000107e64cf1 0000000107e64cc4 0000000107e64c73
	    GPR20: 0000000107e64c31 0000000107e64bf1 0000000107e64be7 0000000000000000
	    GPR24: 0000000000000000 00007fffc9439ee0 0000000000000003 0000000000000001
	    GPR28: 00007fffc943f713 0000000000000000 00007fffc9439ee8 0000000000000000
  [770.648] NIP [00007fff94126800] 0x7fff94126800
  [770.648] LR [0000000107e0b594] 0x107e0b594
  [770.648] --- interrupt: c00
  [770.648] Instruction dump:
  [770.648] 3b00ffe4 e8898828 481175f5 60000000 4bfff4fc 3be00000 4bfff570 3d220000
  [770.648] 7fc4f378 e8698830 4811cd95 e8410018 <0fe00000> f9c10060 f9e10068 fa010070
  [770.648] ---[ end trace 0000000000000000 ]---
  [770.648] BTRFS: error (device dm-2: state A) in find_free_extent_update_loop:4122: errno=-22 unknown
  [770.648] BTRFS info (device dm-2: state EA): forced readonly
  [770.648] BTRFS: error (device dm-2: state EA) in __btrfs_free_extent:3070: errno=-22 unknown
  [770.648] BTRFS error (device dm-2: state EA): failed to run delayed ref for logical 17838685708288 num_bytes 24576 type 184 action 2 ref_mod 1: -22
  [770.648] BTRFS: error (device dm-2: state EA) in btrfs_run_delayed_refs:2144: errno=-22 unknown
  [770.648] BTRFS: error (device dm-2: state EA) in reset_balance_state:3599: errno=-22 unknown

Fixes: 47e6f7423b ("btrfs: add support for 3-copy replication (raid1c3)")
Fixes: 8d6fac0087 ("btrfs: add support for 4-copy replication (raid1c4)")
CC: stable@vger.kernel.org # 5.10+
Signed-off-by: Matt Corallo <blnxfsl@bluematt.me>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:56 +02:00
Filipe Manana
532da3822a btrfs: do not BUG_ON() on tree mod log failure at balance_level()
commit 39020d8abc upstream.

At balance_level(), instead of doing a BUG_ON() in case we fail to record
tree mod log operations, do a transaction abort and return the error to
the callers. There's really no need for the BUG_ON() as we can release
all resources in this context, and we have to abort because other future
tree searches that use the tree mod log (btrfs_search_old_slot()) may get
inconsistent results if other operations modify the tree after that
failure and before the tree mod log based search.

CC: stable@vger.kernel.org # 5.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:22 +02:00
Filipe Manana
8ce9139aea btrfs: fix race when deleting free space root from the dirty cow roots list
commit babebf023e upstream.

When deleting the free space tree we are deleting the free space root
from the list fs_info->dirty_cowonly_roots without taking the lock that
protects it, which is struct btrfs_fs_info::trans_lock.
This unsynchronized list manipulation may cause chaos if there's another
concurrent manipulation of this list, such as when adding a root to it
with ctree.c:add_root_to_dirty_list().

This can result in all sorts of weird failures caused by a race, such as
the following crash:

  [337571.278245] general protection fault, probably for non-canonical address 0xdead000000000108: 0000 [#1] PREEMPT SMP PTI
  [337571.278933] CPU: 1 PID: 115447 Comm: btrfs Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1
  [337571.279153] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [337571.279572] RIP: 0010:commit_cowonly_roots+0x11f/0x250 [btrfs]
  [337571.279928] Code: 85 38 06 00 (...)
  [337571.280363] RSP: 0018:ffff9f63446efba0 EFLAGS: 00010206
  [337571.280582] RAX: ffff942d98ec2638 RBX: ffff9430b82b4c30 RCX: 0000000449e1c000
  [337571.280798] RDX: dead000000000100 RSI: ffff9430021e4900 RDI: 0000000000036070
  [337571.281015] RBP: ffff942d98ec2000 R08: ffff942d98ec2000 R09: 000000000000015b
  [337571.281254] R10: 0000000000000009 R11: 0000000000000001 R12: ffff942fe8fbf600
  [337571.281476] R13: ffff942dabe23040 R14: ffff942dabe20800 R15: ffff942d92cf3b48
  [337571.281723] FS:  00007f478adb7340(0000) GS:ffff94349fa40000(0000) knlGS:0000000000000000
  [337571.281950] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [337571.282184] CR2: 00007f478ab9a3d5 CR3: 000000001e02c001 CR4: 0000000000370ee0
  [337571.282416] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [337571.282647] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [337571.282874] Call Trace:
  [337571.283101]  <TASK>
  [337571.283327]  ? __die_body+0x1b/0x60
  [337571.283570]  ? die_addr+0x39/0x60
  [337571.283796]  ? exc_general_protection+0x22e/0x430
  [337571.284022]  ? asm_exc_general_protection+0x22/0x30
  [337571.284251]  ? commit_cowonly_roots+0x11f/0x250 [btrfs]
  [337571.284531]  btrfs_commit_transaction+0x42e/0xf90 [btrfs]
  [337571.284803]  ? _raw_spin_unlock+0x15/0x30
  [337571.285031]  ? release_extent_buffer+0x103/0x130 [btrfs]
  [337571.285305]  reset_balance_state+0x152/0x1b0 [btrfs]
  [337571.285578]  btrfs_balance+0xa50/0x11e0 [btrfs]
  [337571.285864]  ? __kmem_cache_alloc_node+0x14a/0x410
  [337571.286086]  btrfs_ioctl+0x249a/0x3320 [btrfs]
  [337571.286358]  ? mod_objcg_state+0xd2/0x360
  [337571.286577]  ? refill_obj_stock+0xb0/0x160
  [337571.286798]  ? seq_release+0x25/0x30
  [337571.287016]  ? __rseq_handle_notify_resume+0x3ba/0x4b0
  [337571.287235]  ? percpu_counter_add_batch+0x2e/0xa0
  [337571.287455]  ? __x64_sys_ioctl+0x88/0xc0
  [337571.287675]  __x64_sys_ioctl+0x88/0xc0
  [337571.287901]  do_syscall_64+0x38/0x90
  [337571.288126]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [337571.288352] RIP: 0033:0x7f478aaffe9b

So fix this by locking struct btrfs_fs_info::trans_lock before deleting
the free space root from that list.

Fixes: a5ed918285 ("Btrfs: implement the free space B-tree")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19 16:36:22 +02:00
Christoph Hellwig
ad87179a20 btrfs: fix file_offset for REQ_BTRFS_ONE_ORDERED bios that get split
[ Upstream commit c731cd0b6d ]

If a bio gets split, it needs to have a proper file_offset for checksum
validation and repair to work properly.

Based on feedback from Josef, commit 852eee62d3 ("btrfs: allow
btrfs_submit_bio to split bios") skipped this adjustment for ONE_ORDERED
bios.  But if we actually ever need to split a ONE_ORDERED read bio, this
will lead to a wrong file offset in the repair code.  Right now the only
user of the file_offset is logging of an error message so this is mostly
harmless, but the wrong offset might be more problematic for additional
users in the future.

Fixes: 852eee62d3 ("btrfs: allow btrfs_submit_bio to split bios")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:13 +02:00
Christoph Hellwig
82e3a2913b btrfs: don't treat zoned writeback as being from an async helper thread
[ Upstream commit 7027f87108 ]

When extent_write_locked_range was originally added, it was only used
writing back compressed pages from an async helper thread.  But it is
now also used for writing back pages on zoned devices, where it is
called directly from the ->writepage context.  In this case we want to
be able to pass on the writeback_control instead of creating a new one,
and more importantly want to use all the normal cgroup interaction
instead of potentially deferring writeback to another helper.

Fixes: 898793d992 ("btrfs: zoned: write out partially allocated region")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:13 +02:00
Christoph Hellwig
558c1b78d7 btrfs: only call __extent_writepage_io from extent_write_locked_range
[ Upstream commit eb34dceace ]

__extent_writepage does a lot of things that make no sense for
extent_write_locked_range, given that extent_write_locked_range itself is
called from __extent_writepage either directly or through a workqueue,
and all this work has already been done in the first invocation and the
pages haven't been unlocked since.  Call __extent_writepage_io directly
instead and open code the logic tracked in
btrfs_bio_ctrl::extent_locked.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:13 +02:00
Christoph Hellwig
52f788a170 btrfs: don't fail writeback when allocating the compression context fails
[ Upstream commit 973fb26e81 ]

If cow_file_range_async fails to allocate the asynchronous writeback
context, it currently returns an error and entirely fails the writeback.
This is not a good idea as a writeback failure is a non-temporary error
condition that will make the file system unusable.  Just fall back to
synchronous uncompressed writeback instead.  This requires us to delay
setting the BTRFS_INODE_HAS_ASYNC_EXTENT flag until we've committed to
the async writeback.

The compression checks INODE_NOCOMPRESS and FORCE_COMPRESS are moved
from cow_file_range_async to the preceding checks btrfs_run_delalloc_range().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:13 +02:00
Christoph Hellwig
0e0e5d0b47 btrfs: fix range_end calculation in extent_write_locked_range
[ Upstream commit 36614a3beb ]

The range_end field in struct writeback_control is inclusive, just like
the end parameter passed to extent_write_locked_range.  Not doing this
could cause extra writeout, which is harmless but suboptimal.

Fixes: 771ed689d2 ("Btrfs: Optimize compressed writeback and reads")
CC: stable@vger.kernel.org # 5.9+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:13 +02:00
Christoph Hellwig
6db5fffba5 btrfs: submit a writeback bio per extent_buffer
[ Upstream commit 50b21d7a06 ]

Stop trying to cluster writes of multiple extent_buffers into a single
bio.  There is no need for that as the blk_plug mechanism used all the
way up in writeback_inodes_wb gives us the same I/O pattern even with
multiple bios.  Removing the clustering simplifies
lock_extent_buffer_for_io a lot and will also allow passing the eb
as private data to the end I/O handler.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:13 +02:00
Christoph Hellwig
aea3cea8ea btrfs: return bool from lock_extent_buffer_for_io
[ Upstream commit 9fdd160160 ]

lock_extent_buffer_for_io never returns a negative error value, so switch
the return value to a simple bool.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
[ keep noinline_for_stack ]
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:12 +02:00
Christoph Hellwig
20409d5140 btrfs: don't use btrfs_bio_ctrl for extent buffer reading
[ Upstream commit b78b98e06f ]

The btrfs_bio_ctrl machinery is overkill for reading extent_buffers
as we always operate on PAGE_SIZE chunks (or one smaller one for the
subpage case) that are contiguous and are guaranteed to fit into a
single bio.  Replace it with open coded btrfs_bio_alloc, __bio_add_page
and btrfs_submit_bio calls in a helper function shared between
the subpage and node size >= PAGE_SIZE cases.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:12 +02:00
Christoph Hellwig
110b32eea2 btrfs: always read the entire extent_buffer
[ Upstream commit e95382834c ]

Currently read_extent_buffer_pages skips pages that are already uptodate
when reading in an extent_buffer.  While this reduces the amount of data
read, it increases the number of I/O operations as we now need to do
multiple I/Os when reading an extent buffer with one or more uptodate
pages in the middle of it.  On any modern storage device, be that hard
drives or SSDs this actually decreases I/O performance.  Fortunately
this case is pretty rare as the pages are always initially read together
and then aged the same way.  Besides simplifying the code a bit as-is
this will allow for major simplifications to the I/O completion handler
later on.

Note that the case where all pages are uptodate is still handled by an
optimized fast path that does not read any data from disk.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@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>
Stable-dep-of: 7027f87108 ("btrfs: don't treat zoned writeback as being from an async helper thread")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:35:12 +02:00
Linus Torvalds
569fa9392d for-6.4-rc7-tag
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Merge tag 'for-6.4-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "Unfortunately the recent u32 overflow fix was not complete, there was
  one conversion left, assertion not triggered by my tests but caught by
  Qu's fstests case.

  The "cleanup for later" has been promoted to a proper fix and wraps
  all uses of the stripe left shift so the diffstat has grown but leaves
  no potentially problematic uses.

  We should have done it that way before, sorry"

* tag 'for-6.4-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix remaining u32 overflows when left shifting stripe_nr
2023-06-23 16:09:53 -07:00
Qu Wenruo
cb091225a5 btrfs: fix remaining u32 overflows when left shifting stripe_nr
There was regression caused by a97699d1d6 ("btrfs: replace
map_lookup->stripe_len by BTRFS_STRIPE_LEN") and supposedly fixed by
a7299a18a1 ("btrfs: fix u32 overflows when left shifting stripe_nr").
To avoid code churn the fix was open coding the type casts but
unfortunately missed one which was still possible to hit [1].

The missing place was assignment of bioc->full_stripe_logical inside
btrfs_map_block().

Fix it by adding a helper that does the safe calculation of the offset
and use it everywhere even though it may not be strictly necessary due
to already using u64 types.  This replaces all remaining
"<< BTRFS_STRIPE_LEN_SHIFT" calls.

[1] https://lore.kernel.org/linux-btrfs/20230622065438.86402-1-wqu@suse.com/

Fixes: a7299a18a1 ("btrfs: fix u32 overflows when left shifting stripe_nr")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-22 17:03:55 +02:00
Linus Torvalds
4b0c7a1ba0 for-6.4-rc7-tag
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Merge tag 'for-6.4-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "One more regression fix for an assertion failure that uncovered a
  nasty problem with stripe calculations. This is caused by a u32
  overflow when there are enough devices. The fstests require 6 so this
  hasn't been caught, I was able to hit it with 8.

  The fix is minimal and only adds u64 casts, we'll clean that up later.
  I did various additional tests to be sure"

* tag 'for-6.4-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix u32 overflows when left shifting stripe_nr
2023-06-20 14:38:21 -07:00
Qu Wenruo
a7299a18a1 btrfs: fix u32 overflows when left shifting stripe_nr
[BUG]
David reported an ASSERT() get triggered during fio load on 8 devices
with data/raid6 and metadata/raid1c3:

  fio --rw=randrw --randrepeat=1 --size=3000m \
	  --bsrange=512b-64k --bs_unaligned \
	  --ioengine=libaio --fsync=1024 \
	  --name=job0 --name=job1 \

The ASSERT() is from rbio_add_bio() of raid56.c:

	ASSERT(orig_logical >= full_stripe_start &&
	       orig_logical + orig_len <= full_stripe_start +
	       rbio->nr_data * BTRFS_STRIPE_LEN);

Which is checking if the target rbio is crossing the full stripe
boundary.

  [100.789] assertion failed: orig_logical >= full_stripe_start && orig_logical + orig_len <= full_stripe_start + rbio->nr_data * BTRFS_STRIPE_LEN, in fs/btrfs/raid56.c:1622
  [100.795] ------------[ cut here ]------------
  [100.796] kernel BUG at fs/btrfs/raid56.c:1622!
  [100.797] invalid opcode: 0000 [#1] PREEMPT SMP KASAN
  [100.798] CPU: 1 PID: 100 Comm: kworker/u8:4 Not tainted 6.4.0-rc6-default+ #124
  [100.799] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552-rebuilt.opensuse.org 04/01/2014
  [100.802] Workqueue: writeback wb_workfn (flush-btrfs-1)
  [100.803] RIP: 0010:rbio_add_bio+0x204/0x210 [btrfs]
  [100.806] RSP: 0018:ffff888104a8f300 EFLAGS: 00010246
  [100.808] RAX: 00000000000000a1 RBX: ffff8881075907e0 RCX: ffffed1020951e01
  [100.809] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000001
  [100.811] RBP: 0000000141d20000 R08: 0000000000000001 R09: ffff888104a8f04f
  [100.813] R10: ffffed1020951e09 R11: 0000000000000003 R12: ffff88810e87f400
  [100.815] R13: 0000000041d20000 R14: 0000000144529000 R15: ffff888101524000
  [100.817] FS:  0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000
  [100.821] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [100.822] CR2: 000055d54e44c270 CR3: 000000010a9a1006 CR4: 00000000003706a0
  [100.824] Call Trace:
  [100.825]  <TASK>
  [100.825]  ? die+0x32/0x80
  [100.826]  ? do_trap+0x12d/0x160
  [100.827]  ? rbio_add_bio+0x204/0x210 [btrfs]
  [100.827]  ? rbio_add_bio+0x204/0x210 [btrfs]
  [100.829]  ? do_error_trap+0x90/0x130
  [100.830]  ? rbio_add_bio+0x204/0x210 [btrfs]
  [100.831]  ? handle_invalid_op+0x2c/0x30
  [100.833]  ? rbio_add_bio+0x204/0x210 [btrfs]
  [100.835]  ? exc_invalid_op+0x29/0x40
  [100.836]  ? asm_exc_invalid_op+0x16/0x20
  [100.837]  ? rbio_add_bio+0x204/0x210 [btrfs]
  [100.837]  raid56_parity_write+0x64/0x270 [btrfs]
  [100.838]  btrfs_submit_chunk+0x26e/0x800 [btrfs]
  [100.840]  ? btrfs_bio_init+0x80/0x80 [btrfs]
  [100.841]  ? release_pages+0x503/0x6d0
  [100.842]  ? folio_unlock+0x2f/0x60
  [100.844]  ? __folio_put+0x60/0x60
  [100.845]  ? btrfs_do_readpage+0xae0/0xae0 [btrfs]
  [100.847]  btrfs_submit_bio+0x21/0x60 [btrfs]
  [100.847]  submit_one_bio+0x6a/0xb0 [btrfs]
  [100.849]  extent_write_cache_pages+0x395/0x680 [btrfs]
  [100.850]  ? __extent_writepage+0x520/0x520 [btrfs]
  [100.851]  ? mark_usage+0x190/0x190
  [100.852]  extent_writepages+0xdb/0x130 [btrfs]
  [100.853]  ? extent_write_locked_range+0x480/0x480 [btrfs]
  [100.854]  ? mark_usage+0x190/0x190
  [100.854]  ? attach_extent_buffer_page+0x220/0x220 [btrfs]
  [100.855]  ? reacquire_held_locks+0x178/0x280
  [100.856]  ? writeback_sb_inodes+0x245/0x7f0
  [100.857]  do_writepages+0x102/0x2e0
  [100.858]  ? page_writeback_cpu_online+0x10/0x10
  [100.859]  ? __lock_release.isra.0+0x14a/0x4d0
  [100.860]  ? reacquire_held_locks+0x280/0x280
  [100.861]  ? __lock_acquired+0x1e9/0x3d0
  [100.862]  ? do_raw_spin_lock+0x1b0/0x1b0
  [100.863]  __writeback_single_inode+0x94/0x450
  [100.864]  writeback_sb_inodes+0x372/0x7f0
  [100.864]  ? lock_sync+0xd0/0xd0
  [100.865]  ? do_raw_spin_unlock+0x93/0xf0
  [100.866]  ? sync_inode_metadata+0xc0/0xc0
  [100.867]  ? rwsem_optimistic_spin+0x340/0x340
  [100.868]  __writeback_inodes_wb+0x70/0x130
  [100.869]  wb_writeback+0x2d1/0x530
  [100.869]  ? __writeback_inodes_wb+0x130/0x130
  [100.870]  ? lockdep_hardirqs_on_prepare.part.0+0xf1/0x1c0
  [100.870]  wb_do_writeback+0x3eb/0x480
  [100.871]  ? wb_writeback+0x530/0x530
  [100.871]  ? mark_lock_irq+0xcd0/0xcd0
  [100.872]  wb_workfn+0xe0/0x3f0<

[CAUSE]
Commit a97699d1d6 ("btrfs: replace map_lookup->stripe_len by
BTRFS_STRIPE_LEN") changes how we calculate the map length, to reduce
u64 division.

Function btrfs_max_io_len() is to get the length to the stripe boundary.

It calculates the full stripe start offset (inside the chunk) by the
following code:

		*full_stripe_start =
			rounddown(*stripe_nr, nr_data_stripes(map)) <<
			BTRFS_STRIPE_LEN_SHIFT;

The calculation itself is fine, but the value returned by rounddown() is
dependent on both @stripe_nr (which is u32) and nr_data_stripes() (which
returned int).

Thus the result is also u32, then we do the left shift, which can
overflow u32.

If such overflow happens, @full_stripe_start will be a value way smaller
than @offset, causing later "full_stripe_len - (offset -
*full_stripe_start)" to underflow, thus make later length calculation to
have no stripe boundary limit, resulting a write bio to exceed stripe
boundary.

There are some other locations like this, with a u32 @stripe_nr got left
shift, which can lead to a similar overflow.

[FIX]
Fix all @stripe_nr with left shift with a type cast to u64 before the
left shift.

Those involved @stripe_nr or similar variables are recording the stripe
number inside the chunk, which is small enough to be contained by u32,
but their offset inside the chunk can not fit into u32.

Thus for those specific left shifts, a type cast to u64 is necessary so
this patch does not touch them and the code will be cleaned up in the
future to keep the fix minimal.

Reported-by: David Sterba <dsterba@suse.com>
Fixes: a97699d1d6 ("btrfs: replace map_lookup->stripe_len by BTRFS_STRIPE_LEN")
Tested-by: David Sterba <dsterba@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-20 19:10:31 +02:00
Linus Torvalds
4973ca2955 for-6.4-rc6-tag
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Merge tag 'for-6.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two fixes for NOCOW files, a regression fix in scrub and an assertion
  fix:

   - NOCOW fixes:
      - keep length of iomap direct io request in case of a failure
      - properly pass mode of extent reference checking, this can break
        some cases for swapfile

   - fix error value confusion when scrubbing a stripe

   - convert assertion to a proper error handling when loading global
     roots, reported by syzbot"

* tag 'for-6.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: scrub: fix a return value overwrite in scrub_stripe()
  btrfs: do not ASSERT() on duplicated global roots
  btrfs: can_nocow_file_extent should pass down args->strict from callers
  btrfs: fix iomap_begin length for nocow writes
2023-06-16 12:41:56 -07:00
Qu Wenruo
b50f2d048e btrfs: scrub: fix a return value overwrite in scrub_stripe()
[RETURN VALUE OVERWRITE]
Inside scrub_stripe(), we would submit all the remaining stripes after
iterating all extents.

But since flush_scrub_stripes() can return error, we need to avoid
overwriting the existing @ret if there is any error.

However the existing check is doing the wrong check:

	ret2 = flush_scrub_stripes();
	if (!ret2)
		ret = ret2;

This would overwrite the existing @ret to 0 as long as the final flush
detects no critical errors.

[FIX]
We should check @ret other than @ret2 in that case.

Fixes: 8eb3dd17ea ("btrfs: dev-replace: error out if we have unrepaired metadata error during")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-14 18:30:30 +02:00
Qu Wenruo
745806fb45 btrfs: do not ASSERT() on duplicated global roots
[BUG]
Syzbot reports a reproducible ASSERT() when using rescue=usebackuproot
mount option on a corrupted fs.

The full report can be found here:
https://syzkaller.appspot.com/bug?extid=c4614eae20a166c25bf0

  BTRFS error (device loop0: state C): failed to load root csum
  assertion failed: !tmp, in fs/btrfs/disk-io.c:1103
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/ctree.h:3664!
  invalid opcode: 0000 [#1] PREEMPT SMP KASAN
  CPU: 1 PID: 3608 Comm: syz-executor356 Not tainted 6.0.0-rc7-syzkaller-00029-g3800a713b607 #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
  RIP: 0010:assertfail+0x1a/0x1c fs/btrfs/ctree.h:3663
  RSP: 0018:ffffc90003aaf250 EFLAGS: 00010246
  RAX: 0000000000000032 RBX: 0000000000000000 RCX: f21c13f886638400
  RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
  RBP: ffff888021c640a0 R08: ffffffff816bd38d R09: ffffed10173667f1
  R10: ffffed10173667f1 R11: 1ffff110173667f0 R12: dffffc0000000000
  R13: ffff8880229c21f7 R14: ffff888021c64060 R15: ffff8880226c0000
  FS:  0000555556a73300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000055a2637d7a00 CR3: 00000000709c4000 CR4: 00000000003506e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   <TASK>
   btrfs_global_root_insert+0x1a7/0x1b0 fs/btrfs/disk-io.c:1103
   load_global_roots_objectid+0x482/0x8c0 fs/btrfs/disk-io.c:2467
   load_global_roots fs/btrfs/disk-io.c:2501 [inline]
   btrfs_read_roots fs/btrfs/disk-io.c:2528 [inline]
   init_tree_roots+0xccb/0x203c fs/btrfs/disk-io.c:2939
   open_ctree+0x1e53/0x33df fs/btrfs/disk-io.c:3574
   btrfs_fill_super+0x1c6/0x2d0 fs/btrfs/super.c:1456
   btrfs_mount_root+0x885/0x9a0 fs/btrfs/super.c:1824
   legacy_get_tree+0xea/0x180 fs/fs_context.c:610
   vfs_get_tree+0x88/0x270 fs/super.c:1530
   fc_mount fs/namespace.c:1043 [inline]
   vfs_kern_mount+0xc9/0x160 fs/namespace.c:1073
   btrfs_mount+0x3d3/0xbb0 fs/btrfs/super.c:1884

[CAUSE]
Since the introduction of global roots, we handle
csum/extent/free-space-tree roots as global roots, even if no
extent-tree-v2 feature is enabled.

So for regular csum/extent/fst roots, we load them into
fs_info::global_root_tree rb tree.

And we should not expect any conflicts in that rb tree, thus we have an
ASSERT() inside btrfs_global_root_insert().

But rescue=usebackuproot can break the assumption, as we will try to
load those trees again and again as long as we have bad roots and have
backup roots slot remaining.

So in that case we can have conflicting roots in the rb tree, and
triggering the ASSERT() crash.

[FIX]
We can safely remove that ASSERT(), as the caller will properly put the
offending root.

To make further debugging easier, also add two explicit error messages:

- Error message for conflicting global roots
- Error message when using backup roots slot

Reported-by: syzbot+a694851c6ab28cbcfb9c@syzkaller.appspotmail.com
Fixes: abed4aaae4 ("btrfs: track the csum, extent, and free space trees in a rb tree")
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-13 01:21:16 +02:00
Chris Mason
deccae40e4 btrfs: can_nocow_file_extent should pass down args->strict from callers
Commit 619104ba45 ("btrfs: move common NOCOW checks against a file
extent into a helper") changed our call to btrfs_cross_ref_exist() to
always pass false for the 'strict' parameter.  We're passing this down
through the stack so that we can do a full check for cross references
during swapfile activation.

With strict always false, this test fails:

  btrfs subvol create swappy
  chattr +C swappy
  fallocate -l1G swappy/swapfile
  chmod 600 swappy/swapfile
  mkswap swappy/swapfile

  btrfs subvol snap swappy swapsnap
  btrfs subvol del -C swapsnap

  btrfs fi sync /
  sync;sync;sync

  swapon swappy/swapfile

The fix is to just use args->strict, and everyone except swapfile
activation is passing false.

Fixes: 619104ba45 ("btrfs: move common NOCOW checks against a file extent into a helper")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-13 00:01:08 +02:00
Christoph Hellwig
7833b86595 btrfs: fix iomap_begin length for nocow writes
can_nocow_extent can reduce the len passed in, which needs to be
propagated to btrfs_dio_iomap_begin so that iomap does not submit
more data then is mapped.

This problems exists since the btrfs_get_blocks_direct helper was added
in commit c5794e5178 ("btrfs: Factor out write portion of
btrfs_get_blocks_direct"), but the ordered_extent splitting added in
commit b73a6fd1b1 ("btrfs: split partial dio bios before submit")
added a WARN_ON that made a syzkaller test fail.

Reported-by: syzbot+ee90502d5c8fd1d0dd93@syzkaller.appspotmail.com
Fixes: c5794e5178 ("btrfs: Factor out write portion of btrfs_get_blocks_direct")
CC: stable@vger.kernel.org # 6.1+
Tested-by: syzbot+ee90502d5c8fd1d0dd93@syzkaller.appspotmail.com
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-13 00:01:00 +02:00
Linus Torvalds
ace9e12da2 for-6.4-rc6-tag
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Merge tag 'for-6.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A  more fixes and regression fixes:

   - in subpage mode, fix crash when repairing metadata at the end of
     a stripe

   - properly enable async discard when remounting from read-only to
     read-write

   - scrub regression fixes:
      - respect read-only scrub when attempting to do a repair
      - fix reporting of found errors, the stats don't get properly
        accounted after a stripe repair"

* tag 'for-6.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: scrub: also report errors hit during the initial read
  btrfs: scrub: respect the read-only flag during repair
  btrfs: properly enable async discard when switching from RO->RW
  btrfs: subpage: fix a crash in metadata repair path
2023-06-12 10:53:35 -07:00
Qu Wenruo
79b8ee702c btrfs: scrub: also report errors hit during the initial read
[BUG]
After the recent scrub rework introduced in commit e02ee89baa ("btrfs:
scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure"),
btrfs scrub no longer reports repaired errors any more:

  # mkfs.btrfs -f $dev -d DUP
  # mount $dev $mnt
  # xfs_io -f -d -c "pwrite -b 64K -S 0xaa 0 64" $mnt/file
  # umount $dev
  # xfs_io -f -c "pwrite -S 0xff $phy1 64K" $dev # Corrupt the first mirror
  # mount $dev $mnt
  # btrfs scrub start -BR $mnt
  scrub done for 725e7cb7-8a4a-4c77-9f2a-86943619e218
  Scrub started:    Tue Jun  6 14:56:50 2023
  Status:           finished
  Duration:         0:00:00
  	data_extents_scrubbed: 2
  	tree_extents_scrubbed: 18
  	data_bytes_scrubbed: 131072
  	tree_bytes_scrubbed: 294912
  	read_errors: 0
  	csum_errors: 0 <<< No errors here
  	verify_errors: 0
         [...]
  	uncorrectable_errors: 0
  	unverified_errors: 0
  	corrected_errors: 16		<<< Only corrected errors
  	last_physical: 2723151872

This can confuse btrfs-progs, as it relies on the csum_errors to
determine if there is anything wrong.

While on v6.3.x kernels, the report is different:

 	csum_errors: 16			<<<
 	verify_errors: 0
	[...]
 	uncorrectable_errors: 0
 	unverified_errors: 0
 	corrected_errors: 16 <<<

[CAUSE]
In the reworked scrub, we update the scrub progress inside
scrub_stripe_report_errors(), using various bitmaps to update the
result.

For example for csum_errors, we use bitmap_weight() of
stripe->csum_error_bitmap.

Unfortunately at that stage, all error bitmaps (except
init_error_bitmap) are the result of the latest repair attempt, thus if
the stripe is fully repaired, those error bitmaps will all be empty,
resulting the above output mismatch.

To fix this, record the number of errors into stripe->init_nr_*_errors.
Since we don't really care about where those errors are, we only need to
record the number of errors.

Then in scrub_stripe_report_errors(), use those initial numbers to
update the progress other than using the latest error bitmaps.

Fixes: e02ee89baa ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-08 14:34:01 +02:00
Qu Wenruo
1f2030ff6e btrfs: scrub: respect the read-only flag during repair
[BUG]
With recent scrub rework, the scrub operation no longer respects the
read-only flag passed by "-r" option of "btrfs scrub start" command.

  # mkfs.btrfs -f -d raid1 $dev1 $dev2
  # mount $dev1 $mnt
  # xfs_io -f -d -c "pwrite -b 128K -S 0xaa 0 128k" $mnt/file
  # sync
  # xfs_io -c "pwrite -S 0xff $phy1 64k" $dev1
  # xfs_io -c "pwrite -S 0xff $((phy2 + 65536)) 64k" $dev2
  # mount $dev1 $mnt -o ro
  # btrfs scrub start -BrRd $mnt
  Scrub device $dev1 (id 1) done
  Scrub started:    Tue Jun  6 09:59:14 2023
  Status:           finished
  Duration:         0:00:00
         [...]
  	corrected_errors: 16 <<< Still has corrupted sectors
  	last_physical: 1372585984

  Scrub device $dev2 (id 2) done
  Scrub started:    Tue Jun  6 09:59:14 2023
  Status:           finished
  Duration:         0:00:00
         [...]
  	corrected_errors: 16 <<< Still has corrupted sectors
  	last_physical: 1351614464

  # btrfs scrub start -BrRd $mnt
  Scrub device $dev1 (id 1) done
  Scrub started:    Tue Jun  6 10:00:17 2023
  Status:           finished
  Duration:         0:00:00
         [...]
  	corrected_errors: 0 <<< No more errors
  	last_physical: 1372585984

  Scrub device $dev2 (id 2) done
         [...]
  	corrected_errors: 0 <<< No more errors
  	last_physical: 1372585984

[CAUSE]
In the newly reworked scrub code, repair is always submitted no matter
if we're doing a read-only scrub.

[FIX]
Fix it by skipping the write submission if the scrub is a read-only one.

Unfortunately for the report part, even for a read-only scrub we will
still report it as corrected errors, as we know it's repairable, even we
won't really submit the write.

Fixes: e02ee89baa ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-08 13:56:38 +02:00
Chris Mason
981a37bab5 btrfs: properly enable async discard when switching from RO->RW
The async discard uses the BTRFS_FS_DISCARD_RUNNING bit in the fs_info
to force discards off when the filesystem has aborted or we're generally
not able to run discards.  This gets flipped on when we're mounted rw,
and also when we go from ro->rw.

Commit 63a7cb1307 ("btrfs: auto enable discard=async when possible")
enabled async discard by default, and this meant
"mount -o ro /dev/xxx /yyy" had async discards turned on.

Unfortunately, this meant our check in btrfs_remount_cleanup() would see
that discards are already on:

    /* If we toggled discard async */
    if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
	btrfs_test_opt(fs_info, DISCARD_ASYNC))
	    btrfs_discard_resume(fs_info);

So, we'd never call btrfs_discard_resume() when remounting the root
filesystem from ro->rw.

drgn shows this really nicely:

import os
import sys

from drgn.helpers.linux.fs import path_lookup
from drgn import NULL, Object, Type, cast

def btrfs_sb(sb):
    return cast("struct btrfs_fs_info *", sb.s_fs_info)

if len(sys.argv) == 1:
    path = "/"
else:
    path = sys.argv[1]

fs_info = cast("struct btrfs_fs_info *", path_lookup(prog, path).mnt.mnt_sb.s_fs_info)

BTRFS_FS_DISCARD_RUNNING = 1 << prog['BTRFS_FS_DISCARD_RUNNING']
if fs_info.flags & BTRFS_FS_DISCARD_RUNNING:
    print("discard running flag is on")
else:
    print("discard running flag is off")

[root]# mount | grep nvme
/dev/nvme0n1p3 on / type btrfs
(rw,relatime,compress-force=zstd:3,ssd,discard=async,space_cache=v2,subvolid=5,subvol=/)

[root]# ./discard_running.drgn
discard running flag is off

[root]# mount -o remount,discard=sync /
[root]# mount -o remount,discard=async /
[root]# ./discard_running.drgn
discard running flag is on

The fix is to call btrfs_discard_resume() when we're going from ro->rw.
It already checks to make sure the async discard flag is on, so it'll do
the right thing.

Fixes: 63a7cb1307 ("btrfs: auto enable discard=async when possible")
CC: stable@vger.kernel.org # 6.3+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-06 19:44:22 +02:00