From: "J. Bruce Fields" Subject: Re: [PATCH] nfsd: fix hung up of nfs client while sync write data to nfs server Date: Wed, 27 May 2009 18:48:45 -0400 Message-ID: <20090527224845.GE29565@fieldses.org> References: <4A122F83.4020606@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: nfsv4@linux-nfs.org, linux-nfs@vger.kernel.org, Neil Brown To: Wei Yongjun Return-path: Received: from mail.fieldses.org ([141.211.133.115]:42343 "EHLO pickle.fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996AbZE0Wsp (ORCPT ); Wed, 27 May 2009 18:48:45 -0400 In-Reply-To: <4A122F83.4020606@cn.fujitsu.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, May 19, 2009 at 12:03:15PM +0800, Wei Yongjun wrote: > Commit 'Short write in nfsd becomes a full write to the client' > (31dec2538e45e9fff2007ea1f4c6bae9f78db724) broken the sync write. > With the following commands to reproduce: > > $ mount -t nfs -o sync 192.168.0.21:/nfsroot /mnt > $ cd /mnt > $ echo aaaa > temp.txt > > Then nfs client is hung up. > > In SYNC mode the server alaways return the write count 0 to the > client. This is because the value of host_err in nfsd_vfs_write() > will be overwrite in SYNC mode by 'host_err=nfsd_sync(file);', > and then we return host_err(which is now 0) as write count. Undoubtedly correct--applied, thanks! (But it bugs me that I can't reproduce this: I see the client (mounting with -osync, as above) send an unstable write followed by an immediate commit, instead of a stable write. This is with 2.6.29.30-rc7 on client and server.) --b. > > This patch fixed the problem. > > Signed-off-by: Wei Yongjun > --- > fs/nfsd/vfs.c | 6 +++--- > 1 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index 6c68ffd..b660435 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -1015,6 +1015,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset); > set_fs(oldfs); > if (host_err >= 0) { > + *cnt = host_err; > nfsdstats.io_write += host_err; > fsnotify_modify(file->f_path.dentry); > } > @@ -1060,10 +1061,9 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > } > > dprintk("nfsd: write complete host_err=%d\n", host_err); > - if (host_err >= 0) { > + if (host_err >= 0) > err = 0; > - *cnt = host_err; > - } else > + else > err = nfserrno(host_err); > out: > return err; > -- > 1.5.3.8 > > >