ceph: introduce helper to connect to mds export targets

There are a few cases where we need to open sessions with a given mds's
potential export targets.

Signed-off-by: Sage Weil <sage@newdream.net>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 641a8a37e7b3f790304a398fd44f6e3d5b964053..462602ec7fb1623577dd6f696276e3b47a089cf5 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -704,6 +704,43 @@ static int __open_session(struct ceph_mds_client *mdsc,
        return 0;
 }
 
+/*
+ * open sessions for any export targets for the given mds
+ *
+ * called under mdsc->mutex
+ */
+static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
+                                         struct ceph_mds_session *session)
+{
+       struct ceph_mds_info *mi;
+       struct ceph_mds_session *ts;
+       int i, mds = session->s_mds;
+       int target;
+
+       if (mds >= mdsc->mdsmap->m_max_mds)
+               return;
+       mi = &mdsc->mdsmap->m_info[mds];
+       dout("open_export_target_sessions for mds%d (%d targets)\n",
+            session->s_mds, mi->num_export_targets);
+
+       for (i = 0; i < mi->num_export_targets; i++) {
+               target = mi->export_targets[i];
+               ts = __ceph_lookup_mds_session(mdsc, target);
+               if (!ts) {
+                       ts = register_session(mdsc, target);
+                       if (IS_ERR(ts))
+                               return;
+               }
+               if (session->s_state == CEPH_MDS_SESSION_NEW ||
+                   session->s_state == CEPH_MDS_SESSION_CLOSING)
+                       __open_session(mdsc, session);
+               else
+                       dout(" mds%d target mds%d %p is %s\n", session->s_mds,
+                            i, ts, session_state_name(ts->s_state));
+               ceph_put_mds_session(ts);
+       }
+}
+
 /*
  * session caps
  */