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>

1 files changed, 37 insertions, 0 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 641a8a37e7b3..462602ec7fb1 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -705,6 +705,43 @@ static int __open_session(struct ceph_mds_client *mdsc,
 }
 
 /*
+ * 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
  */