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Date:   Wed, 11 Dec 2019 15:04:54 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     "Theodore Y. Ts'o" <tytso@....edu>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        stable@...nel.org, Andreas Dilger <adilger@...ger.ca>,
        linux-ext4@...r.kernel.org
Subject: Re: [PATCH AUTOSEL 4.4 27/37] ext4: work around deleting a file with
 i_nlink == 0 safely

On Wed, Dec 11, 2019 at 11:19:59AM -0500, Theodore Y. Ts'o wrote:
>On Wed, Dec 11, 2019 at 10:38:03AM -0500, Sasha Levin wrote:
>> From: Theodore Ts'o <tytso@....edu>
>>
>> [ Upstream commit c7df4a1ecb8579838ec8c56b2bb6a6716e974f37 ]
>>
>> If the file system is corrupted such that a file's i_links_count is
>> too small, then it's possible that when unlinking that file, i_nlink
>> will already be zero.  Previously we were working around this kind of
>> corruption by forcing i_nlink to one; but we were doing this before
>> trying to delete the directory entry --- and if the file system is
>> corrupted enough that ext4_delete_entry() fails, then we exit with
>> i_nlink elevated, and this causes the orphan inode list handling to be
>> FUBAR'ed, such that when we unmount the file system, the orphan inode
>> list can get corrupted.
>>
>> A better way to fix this is to simply skip trying to call drop_nlink()
>> if i_nlink is already zero, thus moving the check to the place where
>> it makes the most sense.
>>
>> https://bugzilla.kernel.org/show_bug.cgi?id=205433
>>
>> Link: https://lore.kernel.org/r/20191112032903.8828-1-tytso@mit.edu
>> Signed-off-by: Theodore Ts'o <tytso@....edu>
>> Cc: stable@...nel.org
>> Reviewed-by: Andreas Dilger <adilger@...ger.ca>
>> Signed-off-by: Sasha Levin <sashal@...nel.org>
>
>I'm confused; this was explicitly cc'ed to stable@...nel.org, so why
>is your AUTOSEL picking this up?  I would have thought this would get
>picked up via the normal stable kernel processes.

My mistake, appologies.

-- 
Thanks,
Sasha

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