Return-Path: Received: from fieldses.org ([174.143.236.118]:60407 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335Ab1ANSQC (ORCPT ); Fri, 14 Jan 2011 13:16:02 -0500 Date: Fri, 14 Jan 2011 13:16:00 -0500 To: Fu Liankun Cc: linux-nfs@vger.kernel.org Subject: Re: [PATCH] NFSV4 :All lock operations should be sent to the server for resolution Message-ID: <20110114181600.GA15352@fieldses.org> References: <4D2FF124.7020500@cn.fujitsu.com> Content-Type: text/plain; charset=us-ascii In-Reply-To: <4D2FF124.7020500@cn.fujitsu.com> From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Fri, Jan 14, 2011 at 02:45:56PM +0800, Fu Liankun wrote: > The RFC3530 describes that the client's all lock operations, including those > requesting non-exclusive locks, should be sent to the server for resolution, > even if it holds a read open delegation. But the kernel implements like that > lock operations can be performed locally when a client holds an open > delegation. > > The following are the RFC3530 provisions for Open Delegation and File Locks: > > 9.4.2. Open Delegation and File Locks > > When a client holds a write open delegation, lock operations may be > performed locally. This includes those required for mandatory file > locking. This can be done since the delegation implies that there > can be no conflicting locks. Similarly, all of the revalidations > that would normally be associated with obtaining locks and the > flushing of data associated with the releasing of locks need not be > done. > > When a client holds a read open delegation, lock operations are not > performed locally. All lock operations, including those requesting > non-exclusive locks, are sent to the server for resolution. Weird. Can the rfc really be right about that? I guess it does permit servers to allow write-locks on read-open files, but it seems bizarre not to require them to break delegations in that case. --b. > > Signed-off-by: Fu Liankun > --- > fs/nfs/nfs4proc.c | 7 ------- > 1 files changed, 0 insertions(+), 7 deletions(-) > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index 0f24cdf..3bba85b 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -4215,13 +4215,6 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock > if (status < 0) > goto out; > down_read(&nfsi->rwsem); > - if (test_bit(NFS_DELEGATED_STATE, &state->flags)) { > - /* Yes: cache locks! */ > - /* ...but avoid races with delegation recall... */ > - request->fl_flags = fl_flags & ~FL_SLEEP; > - status = do_vfs_lock(request->fl_file, request); > - goto out_unlock; > - } > status = _nfs4_do_setlk(state, cmd, request, NFS_LOCK_NEW); > if (status != 0) > goto out_unlock; > -- > 1.7.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html