linux-kernel - Re: [PATCH AUTOSEL 4.4 27/37] ext4: work around deleting a file with i

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Message-ID: <20191211161959.GB129186@mit.edu>
Date:   Wed, 11 Dec 2019 11:19:59 -0500
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Sasha Levin <sashal@...nel.org>
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 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.

Thanks,

						- Ted