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Date:   Tue, 1 Dec 2020 15:12:51 -0500
From:   "J. Bruce Fields" <bfields@redhat.com>
To:     Jeff Layton <jlayton@kernel.org>
Cc:     "J. Bruce Fields" <bfields@fieldses.org>,
        Chuck Lever <chuck.lever@oracle.com>, linux-nfs@vger.kernel.org
Subject: Re: [PATCH 1/5] nfsd: only call inode_query_iversion in the
 I_VERSION case
Message-ID: <20201201201251.GZ259862@pick.fieldses.org>
References: <1606776378-22381-1-git-send-email-bfields@fieldses.org>
 <e40e0b17e0eff20016b637b140b7fd4b2e367e34.camel@kernel.org>
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On Tue, Dec 01, 2020 at 11:30:12AM -0500, Jeff Layton wrote:
> On Mon, 2020-11-30 at 17:46 -0500, J. Bruce Fields wrote:
> > From: "J. Bruce Fields" <bfields@redhat.com>
> > 
> > inode_query_iversion() can modify i_version.  Depending on the exported
> > filesystem, that may not be safe.  For example, if you're re-exporting
> > NFS, NFS stores the server's change attribute in i_version and does not
> > expect it to be modified locally.  This has been observed causing
> > unnecessary cache invalidations.
> > 
> > The way a filesystem indicates that it's OK to call
> > inode_query_iverson() is by setting SB_I_VERSION.
> > 
> > So, move the I_VERSION check out of encode_change(), where it's used
> > only in FATTR responses, to nfsd4_changeattr(), which is also called for
> > pre- and post- operation attributes.
> > 
> 
> "only in FATTR responses, to nfsd4_change_attribute(),"

Whoops, and also FATTR should have been GETATTR.

Fixed locally, I assume Chuck will just want to fix that up in his tree
(let me know if not).

--b.