Revert "NFSv4: Fall back to ordinary lookup if nfs4_atomic_open() returns EISDIR"

This reverts commit 80e60639f1b7c121a7fea53920c5a4b94009361a.

This change requires further fixes to ensure that the open doesn't
succeed if the lookup later results in a regular file being created.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/dir.c

@@ -1345,12 +1345,12 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry
 				res = NULL;
 				goto out;
 			/* This turned out not to be a regular file */
-			case -EISDIR:
 			case -ENOTDIR:
 				goto no_open;
 			case -ELOOP:
 				if (!(nd->intent.open.flags & O_NOFOLLOW))
 					goto no_open;
+			/* case -EISDIR: */
 			/* case -EINVAL: */
 			default:
 				res = ERR_CAST(inode);