Return-Path: Received: from bombadil.infradead.org ([18.85.46.34]:55681 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932346Ab0BDPT1 (ORCPT ); Thu, 4 Feb 2010 10:19:27 -0500 Date: Thu, 4 Feb 2010 10:19:26 -0500 From: Christoph Hellwig To: Ben Myers Cc: linux-nfs@vger.kernel.org Subject: Re: [RFC PATCH 4/4] If 'wsync' pass datasync=1 to vfs_fsync(). Message-ID: <20100204151926.GA22014@infradead.org> References: <20100203233755.17677.96582.stgit@case> <20100203234444.17677.32390.stgit@case> Content-Type: text/plain; charset=us-ascii In-Reply-To: <20100203234444.17677.32390.stgit@case> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Wed, Feb 03, 2010 at 05:44:44PM -0600, Ben Myers wrote: > > --- > fs/nfsd/vfs.c | 39 +++++++++++++++++++++++++-------------- > 1 files changed, 25 insertions(+), 14 deletions(-) > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index 89eb1b2..4b1973b 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -418,7 +418,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, > if (!err) { > if (EX_ISSYNC(fhp->fh_export)) { > if (EX_ISWSYNC(fhp->fh_export)) { > - vfs_fsync(NULL, dentry, 0); > + vfs_fsync(NULL, dentry, 1); I think this is incorrect. datasync = 1 means to only write out metadata that is required to access the file data. The write_inode code makes sure all metadata goes out, which AFAIK is what the NFS protocol requires from us anyway for all these metadata operations. Note that this does not invalidate your XFS numbers as right now XFS doesn't actually implement the datasync == 1 optimization, although I'm about to send a patch to do that. The updsize is that this will make your patchset quite a bit simpler :)