From: Wei Yongjun Subject: [PATCH] nfsd: fix hung up of nfs client while sync write data to nfs server Date: Tue, 19 May 2009 12:03:15 +0800 Message-ID: <4A122F83.4020606@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 To: nfsv4@linux-nfs.org, linux-nfs@vger.kernel.org, "J. Bruce Fields" , Neil Brown Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:49836 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750750AbZESEGq (ORCPT ); Tue, 19 May 2009 00:06:46 -0400 Sender: linux-nfs-owner@vger.kernel.org List-ID: 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. 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