ceph: Check for err on mds request in atomic_open

The error returned by ceph_mdsc_do_request includes errors sending the
request, errors on timeout, or any errors coming from the mds.  If
ceph_mdsc_do_request returns an error, the reply struct will most likely
be bogus.  We need to bail out and propogate the error instead of
overwriting it.
Signed-off-by: Sam Lang <sam.lang@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

fs/ceph/file.c

@@ -243,6 +243,9 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 	err = ceph_mdsc_do_request(mdsc,
 				   (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
 				   req);
+	if (err)
+		goto out_err;
+
 	err = ceph_handle_snapdir(req, dentry, err);
 	if (err == 0 && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
 		err = ceph_handle_notrace_create(dir, dentry);