ceph: handle -ESTALE reply

Send requests that operate on path to directory's auth MDS if
mode == USE_AUTH_MDS. Always retry using the auth MDS if got
-ESTALE reply from non-auth MDS. Also clean up the code that
handles auth MDS change.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

fs/ceph/mds_client.c

@@ -713,14 +713,15 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 			struct dentry *dn = get_nonsnap_parent(parent);
 			inode = dn->d_inode;
 			dout("__choose_mds using nonsnap parent %p\n", inode);
-		} else if (req->r_dentry->d_inode) {
+		} else {
 			/* dentry target */
 			inode = req->r_dentry->d_inode;
-		} else {
-			/* dir + name */
-			inode = dir;
-			hash = ceph_dentry_hash(dir, req->r_dentry);
-			is_hash = true;
+			if (!inode || mode == USE_AUTH_MDS) {
+				/* dir + name */
+				inode = dir;
+				hash = ceph_dentry_hash(dir, req->r_dentry);
+				is_hash = true;
+			}
 		}
 	}
 
@@ -2161,26 +2162,16 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	 */
 	if (result == -ESTALE) {
 		dout("got ESTALE on request %llu", req->r_tid);
-		if (!req->r_inode) {
-			/* do nothing; not an authority problem */
-		} else if (req->r_direct_mode != USE_AUTH_MDS) {
+		if (req->r_direct_mode != USE_AUTH_MDS) {
 			dout("not using auth, setting for that now");
 			req->r_direct_mode = USE_AUTH_MDS;
 			__do_request(mdsc, req);
 			mutex_unlock(&mdsc->mutex);
 			goto out;
 		} else  {
-			struct ceph_inode_info *ci = ceph_inode(req->r_inode);
-			struct ceph_cap *cap = NULL;
-
-			if (req->r_session)
-				cap = ceph_get_cap_for_mds(ci,
-						   req->r_session->s_mds);
-
-			dout("already using auth");
-			if ((!cap || cap != ci->i_auth_cap) ||
-			    (cap->mseq != req->r_sent_on_mseq)) {
-				dout("but cap changed, so resending");
+			int mds = __choose_mds(mdsc, req);
+			if (mds >= 0 && mds != req->r_session->s_mds) {
+				dout("but auth changed, so resending");
 				__do_request(mdsc, req);
 				mutex_unlock(&mdsc->mutex);
 				goto out;