From b9148c6b80d802dbc2a7530b29915a80432e50c7 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever@oracle.com>
Date: Mon, 12 Nov 2007 12:16:58 -0500
Subject: [PATCH] NFS: Ensure we return zero if applications attempt to write
 zero bytes

A zero byte count direct write request should be a successful no-op, not an
error.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/direct.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 88d5d1c7f9..4d726e9db2 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -890,6 +890,8 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
 	retval = generic_write_checks(file, &pos, &count, 0);
 	if (retval)
 		goto out;
+	if (!count)
+		goto out;	/* return 0 */
 
 	retval = -EINVAL;
 	if ((ssize_t) count < 0)
-- 
2.39.5