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 <yjwei@xxxxxxxxxxxxxx>
> ---
> 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
>
>
>
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