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From: Sasha Levin <sashal@kernel.org>
To: Omar Sandoval <osandov@osandov.com>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Omar Sandoval <osandov@fb.com>,
	Josef Bacik <josef@toxicpanda.com>,
	Nikolay Borisov <nborisov@suse.com>,
	David Sterba <dsterba@suse.com>,
	clm@fb.com, jbacik@fb.com, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.17 12/21] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio()
Date: Thu, 31 Mar 2022 12:58:28 -0400	[thread overview]
Message-ID: <YkXdtBfNbH2/oP5z@sashalap> (raw)
In-Reply-To: <YkNko1BcsyDt2QUS@relinquished.localdomain>

On Tue, Mar 29, 2022 at 12:57:23PM -0700, Omar Sandoval wrote:
>On Mon, Mar 28, 2022 at 03:41:47PM -0400, Sasha Levin wrote:
>> From: Omar Sandoval <osandov@fb.com>
>>
>> [ Upstream commit e331f6b19f8adde2307588bb325ae5de78617c20 ]
>>
>> btrfs_csum_one_bio() loops over each filesystem block in the bio while
>> keeping a cursor of its current logical position in the file in order to
>> look up the ordered extent to add the checksums to. However, this
>> doesn't make much sense for compressed extents, as a sector on disk does
>> not correspond to a sector of decompressed file data. It happens to work
>> because:
>>
>> 1) the compressed bio always covers one ordered extent
>> 2) the size of the bio is always less than the size of the ordered
>>    extent
>>
>> However, the second point will not always be true for encoded writes.
>>
>> Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that
>> it can assume that the bio only covers one ordered extent. Since we're
>> already changing the signature, let's get rid of the contig parameter
>> and make it implied by the offset parameter, similar to the change we
>> recently made to btrfs_lookup_bio_sums(). Additionally, let's rename
>> nr_sectors to blockcount to make it clear that it's the number of
>> filesystem blocks, not the number of 512-byte sectors.
>>
>> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
>> Reviewed-by: Nikolay Borisov <nborisov@suse.com>
>> Signed-off-by: Omar Sandoval <osandov@fb.com>
>> Signed-off-by: David Sterba <dsterba@suse.com>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>>  fs/btrfs/compression.c |  2 +-
>>  fs/btrfs/ctree.h       |  2 +-
>>  fs/btrfs/file-item.c   | 37 +++++++++++++++++--------------------
>>  fs/btrfs/inode.c       |  8 ++++----
>>  4 files changed, 23 insertions(+), 26 deletions(-)
>
>Hi, Sasha,
>
>This patch doesn't fix a real bug, so it should be dropped from both
>5.16 and 5.17.

I'll drop it, thanks.

-- 
Thanks,
Sasha

  reply	other threads:[~2022-03-31 16:58 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-28 19:41 [PATCH AUTOSEL 5.17 01/21] atomics: Fix atomic64_{read_acquire,set_release} fallbacks Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 02/21] locking/lockdep: Iterate lock_classes directly when reading lockdep files Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 03/21] ext4: correct cluster len and clusters changed accounting in ext4_mb_mark_bb Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 04/21] ext4: fix ext4_mb_mark_bb() with flex_bg with fast_commit Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 05/21] sched/tracing: Don't re-read p->state when emitting sched_switch event Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 06/21] sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 07/21] ext4: don't BUG if someone dirty pages without asking ext4 first Sasha Levin
2022-03-28 19:42   ` syzbot
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 08/21] f2fs: fix to do sanity check on curseg->alloc_type Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 09/21] NFSD: Fix nfsd_breaker_owns_lease() return values Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 10/21] f2fs: don't get FREEZE lock in f2fs_evict_inode in frozen fs Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 11/21] btrfs: harden identification of a stale device Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 12/21] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio() Sasha Levin
2022-03-29 19:57   ` Omar Sandoval
2022-03-31 16:58     ` Sasha Levin [this message]
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 13/21] btrfs: make search_csum_tree return 0 if we get -EFBIG Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 14/21] btrfs: handle csum lookup errors properly on reads Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 15/21] btrfs: do not double complete bio on errors during compressed reads Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 16/21] btrfs: do not clean up repair bio if submit fails Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 17/21] btrfs: reset last_reflink_trans after fsyncing inode Sasha Levin
2022-03-29  9:59   ` Filipe Manana
2022-03-31 16:59     ` Sasha Levin
2022-03-31 17:57       ` Filipe Manana
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 18/21] f2fs: use spin_lock to avoid hang Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 19/21] f2fs: compress: fix to print raw data size in error path of lz4 decompression Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 20/21] Adjust cifssb maximum read size Sasha Levin
2022-03-28 19:41 ` [PATCH AUTOSEL 5.17 21/21] ntfs: add sanity check on allocation size Sasha Levin

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