NFS: Fix NFSv3 exclusive open semantics

Commit c0204fd2b8 (NFS: Clean up
nfs4_proc_create()) broke NFSv3 exclusive open by removing the code
that passes the O_EXCL flag down to nfs3_proc_create(). This patch
reverts that offending hunk from the original commit.

Reported-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org    [2.6.37]
Tested-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nfs/dir.c

@@ -1579,6 +1579,7 @@ static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
 {
 	struct iattr attr;
 	int error;
+	int open_flags = 0;
 
 	dfprintk(VFS, "NFS: create(%s/%ld), %s\n",
 			dir->i_sb->s_id, dir->i_ino, dentry->d_name.name);
@@ -1586,7 +1587,10 @@ static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
 	attr.ia_mode = mode;
 	attr.ia_valid = ATTR_MODE;
 
-	error = NFS_PROTO(dir)->create(dir, dentry, &attr, 0, NULL);
+	if ((nd->flags & LOOKUP_CREATE) != 0)
+		open_flags = nd->intent.open.flags;
+
+	error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, NULL);
 	if (error != 0)
 		goto out_err;
 	return 0;