ceph: do not confuse stale and dead (unreconnected) caps

We were using the cap_gen to track both stale caps (caps that timed out
due to temporarily losing touch with the mds) and dead caps that did not
reconnect after an MDS failure.  Introduce a recon_gen counter to track
reconnections to restarted MDSs and kill dead caps based on that instead.

Rename gen to cap_gen while we're at it to make it more clear which is
which.

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

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 210cb6623ea2..828417ae16f9 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -329,6 +329,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
         ceph_con_open(&s->s_con, ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
 
         spin_lock_init(&s->s_cap_lock);
+        s->s_recon_gen = 0;
         s->s_cap_gen = 0;
         s->s_cap_ttl = 0;
         s->s_renew_requested = 0;
@@ -738,10 +739,11 @@ static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
         struct ceph_mds_session *session = arg;
 
         spin_lock(&inode->i_lock);
-        if (cap->gen != session->s_cap_gen) {
+        if (cap->recon_gen != session->s_recon_gen) {
                 pr_err("failed reconnect %p %llx.%llx cap %p "
-                       "(gen %d < session %d)\n", inode, ceph_vinop(inode),
-                       cap, cap->gen, session->s_cap_gen);
+                       "(recon_gen %d < session %d)\n", inode,
+                       ceph_vinop(inode), cap,
+                       cap->recon_gen, session->s_recon_gen);
                 __ceph_remove_cap(cap, NULL);
         }
         wake_up(&ceph_inode(inode)->i_cap_wq);
@@ -2050,6 +2052,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc, int mds)
 
                 session->s_state = CEPH_MDS_SESSION_RECONNECTING;
                 session->s_seq = 0;
+                session->s_recon_gen++;
 
                 ceph_con_open(&session->s_con,
                               ceph_mdsmap_get_addr(mdsc->mdsmap, mds));