Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:44411 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751983Ab3EUTXk (ORCPT ); Tue, 21 May 2013 15:23:40 -0400 Date: Tue, 21 May 2013 15:23:38 -0400 To: Steve Dickson Cc: Bruce Fields , Linux NFS Mailing list Subject: Re: [PATCH] NFSD: Don't give out read delegations on exclusive creates Message-ID: <20130521192338.GC12114@fieldses.org> References: <1368643909-8059-1-git-send-email-steved@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1368643909-8059-1-git-send-email-steved@redhat.com> From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, May 15, 2013 at 02:51:49PM -0400, Steve Dickson wrote: > When an exclusive create is done with the mode bits > set (aka open(testfile, O_CREAT | O_EXCL, 0777)) this so implicitly O_RDONLY. Is that common? Maybe so, OK. > causes a OPEN op followed by a SETATTR op. When a > read delegation is given in the OPEN, it causes > the SETATTR to delay with EAGAIN until the > delegation is recalled. > > This patch caused exclusive creates to give out > a write delegation (which turn into no delegation) > which allows the SETATTR seamlessly succeed. OK. May as well make it apply to all creates, though, I think? Any create flag seems like a sign the file's likely to be modified soon, hence isn't a good candidate for a read delegation. I find it a little confusing the way we set this WRITE flag and then depend on later code to turn that into no delegation, maybe we should fix that. --b. > > Signed-off-by: Steve Dickson > --- > fs/nfsd/nfs4state.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 316ec84..6b45d0e 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -3035,8 +3035,16 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh, > goto out; > if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) > flag = NFS4_OPEN_DELEGATE_WRITE; > - else > - flag = NFS4_OPEN_DELEGATE_READ; > + else { > + switch(open->op_createmode) { > + case NFS4_CREATE_EXCLUSIVE: > + case NFS4_CREATE_EXCLUSIVE4_1: > + flag = NFS4_OPEN_DELEGATE_WRITE; > + break; > + default: > + flag = NFS4_OPEN_DELEGATE_READ; > + } > + } > break; > default: > goto out; > -- > 1.8.1.4 >