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Subject: Re: [PATCH 4/4] nfs: support i_version in the NFSv4 case
From:   Jeff Layton <jlayton@kernel.org>
To:     "J. Bruce Fields" <bfields@redhat.com>
Cc:     Daire Byrne <daire@dneg.com>,
        Trond Myklebust <trondmy@hammerspace.com>,
        linux-cachefs <linux-cachefs@redhat.com>,
        linux-nfs <linux-nfs@vger.kernel.org>
Date:   Tue, 17 Nov 2020 07:34:36 -0500
In-Reply-To: <1605583086-19869-4-git-send-email-bfields@redhat.com>
References: <20201117031601.GB10526@fieldses.org>
         <1605583086-19869-1-git-send-email-bfields@redhat.com>
         <1605583086-19869-4-git-send-email-bfields@redhat.com>
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On Mon, 2020-11-16 at 22:18 -0500, J. Bruce Fields wrote:
> From: "J. Bruce Fields" <bfields@redhat.com>
> 
> Currently when knfsd re-exports an NFS filesystem, it uses the ctime as
> the change attribute.  But obviously we have a real change
> attribute--the one that was returned from the original server.  We
> should just use that.
> 
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> ---
>  fs/nfs/super.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 4034102010f0..ca85f81d1b9e 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -1045,6 +1045,7 @@ static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
>  	} else {
>  		sb->s_time_min = S64_MIN;
>  		sb->s_time_max = S64_MAX;
> +		sb->s_flags |= SB_I_VERSION;
>  	}
>  
> 
>  	sb->s_magic = NFS_SUPER_MAGIC;

I don't think we want this change. This will make file_update_time
attempt to bump the i_version field itself using the routines in
iversion.h. This will almost certainly do the wrong thing.

-- 
Jeff Layton <jlayton@kernel.org>