linux-ext4 - Re: [PATCH v2] ext4: fix i

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Message-ID: <20220818073640.nxisir45whbcamtx@wittgenstein>
Date:   Thu, 18 Aug 2022 09:36:40 +0200
From:   Christian Brauner <brauner@...nel.org>
To:     Jan Kara <jack@...e.cz>
Cc:     Jeff Layton <jlayton@...nel.org>, tytso@....edu,
        adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, Lukas Czerner <lczerner@...hat.com>
Subject: Re: [PATCH v2] ext4: fix i_version handling in ext4

On Wed, Aug 17, 2022 at 08:19:03PM +0200, Jan Kara wrote:
> On Wed 17-08-22 12:26:38, Jeff Layton wrote:
> > ext4 currently updates the i_version counter when the atime is updated
> > during a read. This is less than ideal as it can cause unnecessary cache
> > invalidations with NFSv4 and unnecessary remeasurements for IMA. The
> > increment in ext4_mark_iloc_dirty is also problematic since it can also
> > corrupt the i_version counter for ea_inodes. We aren't bumping the file
> > times in ext4_mark_iloc_dirty, so changing the i_version there seems
> > wrong, and is the cause of both problems.
> > 
> > Remove that callsite and add increments to the setattr, setxattr and
> > ioctl codepaths (at the same time that we update the ctime). The
> > i_version bump that already happens during timestamp updates should take
> > care of the rest.
> > 
> > In ext4_move_extents, increment the i_version on both inodes, and also
> > add in missing ctime updates.
> > 
> > Cc: Lukas Czerner <lczerner@...hat.com>
> > Cc: Christian Brauner <brauner@...nel.org>
> > Cc: Jan Kara <jack@...e.cz>
> > Signed-off-by: Jeff Layton <jlayton@...nel.org>
> 
> Hopefully all cases covered ;) Feel free to add:
> 
> Reviewed-by: Jan Kara <jack@...e.cz>

Thanks for making sure all cases are covered. :)
Reviewed-by: Christian Brauner (Microsoft) <brauner@...nel.org>