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Date:   Tue, 12 Jan 2021 14:23:15 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     Christoph Hellwig <hch@lst.de>, linux-fsdevel@vger.kernel.org,
        linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net,
        Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH v2 04/12] fat: only specify I_DIRTY_TIME when needed in
 fat_update_time()
Message-ID: <20210112132315.GA13780@lst.de>
References: <20210109075903.208222-1-ebiggers@kernel.org> <20210109075903.208222-5-ebiggers@kernel.org> <20210111105201.GB2502@lst.de> <X/ysA8PuJ/+JXQYL@sol.localdomain>
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On Mon, Jan 11, 2021 at 11:50:27AM -0800, Eric Biggers wrote:
> On Mon, Jan 11, 2021 at 11:52:01AM +0100, Christoph Hellwig wrote:
> > On Fri, Jan 08, 2021 at 11:58:55PM -0800, Eric Biggers wrote:
> > > +	if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))
> > > +		dirty_flags |= I_DIRTY_SYNC;
> > 
> > fat does not support i_version updates, so this bit can be skipped.
> 
> Is that really the case?  Any filesystem (including fat) can be mounted with
> "iversion", which causes SB_I_VERSION to be set.
> 
> A lot of filesystems (including fat) don't store i_version to disk, but it looks
> like it will still get updated in-memory.  Could anything be relying on that?

As Dave pointed out i_version can't really work for fat.  But I guess
that is indeed out of scope for this series, so let's go ahead with this
version for now:

Reviewed-by: Christoph Hellwig <hch@lst.de>