ceph: drop messages on unregistered mds sessions; cleanup

Verify the mds session is currently registered before handling
incoming messages.  Clean up message handlers to pull mds out
of session->s_mds instead of less trustworthy src field.

Clean up con_{get,put} debug output.

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

4 files changed, 46 insertions, 59 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index b6154ffe70df..bb846164addc 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2600,7 +2600,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
         struct inode *inode;
         struct ceph_cap *cap;
         struct ceph_mds_caps *h;
-        int mds = le64_to_cpu(msg->hdr.src.name.num);
+        int mds = session->s_mds;
         int op;
         u32 seq;
         struct ceph_vino vino;
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 124c0c17a14a..4d00ea2af000 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -309,6 +309,15 @@ static bool __have_session(struct ceph_mds_client *mdsc, int mds)
         return mdsc->sessions[mds];
 }
 
+static int __verify_registered_session(struct ceph_mds_client *mdsc,
+                                       struct ceph_mds_session *s)
+{
+        if (s->s_mds >= mdsc->max_sessions ||
+            mdsc->sessions[s->s_mds] != s)
+                return -ENOENT;
+        return 0;
+}
+
 /*
  * create+register a new session for given mds.
  * called under mdsc->mutex.
@@ -382,10 +391,11 @@ fail_realloc:
 /*
  * called under mdsc->mutex
  */
-static void unregister_session(struct ceph_mds_client *mdsc,
+static void __unregister_session(struct ceph_mds_client *mdsc,
                                struct ceph_mds_session *s)
 {
-        dout("unregister_session mds%d %p\n", s->s_mds, s);
+        dout("__unregister_session mds%d %p\n", s->s_mds, s);
+        BUG_ON(mdsc->sessions[s->s_mds] != s);
         mdsc->sessions[s->s_mds] = NULL;
         ceph_con_close(&s->s_con);
         ceph_put_mds_session(s);
@@ -1740,10 +1750,8 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
         struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
         u64 tid;
         int err, result;
-        int mds;
+        int mds = session->s_mds;
 
-        if (msg->hdr.src.name.type != CEPH_ENTITY_TYPE_MDS)
-                return;
         if (msg->front.iov_len < sizeof(*head)) {
                 pr_err("mdsc_handle_reply got corrupt (short) reply\n");
                 ceph_msg_dump(msg);
@@ -1760,7 +1768,6 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
                 return;
         }
         dout("handle_reply %p\n", req);
-        mds = le64_to_cpu(msg->hdr.src.name.num);
 
         /* correct session? */
         if (!req->r_session && req->r_session != session) {
@@ -1884,7 +1891,9 @@ out:
 /*
  * handle mds notification that our request has been forwarded.
  */
-static void handle_forward(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
+static void handle_forward(struct ceph_mds_client *mdsc,
+                           struct ceph_mds_session *session,
+                           struct ceph_msg *msg)
 {
         struct ceph_mds_request *req;
         u64 tid;
@@ -1894,11 +1903,7 @@ static void handle_forward(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
         int err = -EINVAL;
         void *p = msg->front.iov_base;
         void *end = p + msg->front.iov_len;
-        int from_mds, state;
-
-        if (msg->hdr.src.name.type != CEPH_ENTITY_TYPE_MDS)
-                goto bad;
-        from_mds = le64_to_cpu(msg->hdr.src.name.num);
+        int state;
 
         ceph_decode_need(&p, end, sizeof(u64)+2*sizeof(u32), bad);
         tid = ceph_decode_64(&p);
@@ -1915,6 +1920,9 @@ static void handle_forward(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
                 goto out;  /* dup reply? */
         }
 
+        if (next_mds >= mdsc->max_sessions)
+                goto out;
+
         state = mdsc->sessions[next_mds]->s_state;
         if (fwd_seq <= req->r_num_fwd) {
                 dout("forward %llu to mds%d - old seq %d <= %d\n",
@@ -1945,14 +1953,10 @@ static void handle_session(struct ceph_mds_session *session,
         struct ceph_mds_client *mdsc = session->s_mdsc;
         u32 op;
         u64 seq;
-        int mds;
+        int mds = session->s_mds;
         struct ceph_mds_session_head *h = msg->front.iov_base;
         int wake = 0;
 
-        if (msg->hdr.src.name.type != CEPH_ENTITY_TYPE_MDS)
-                return;
-        mds = le64_to_cpu(msg->hdr.src.name.num);
-
         /* decode */
         if (msg->front.iov_len != sizeof(*h))
                 goto bad;
@@ -1960,6 +1964,8 @@ static void handle_session(struct ceph_mds_session *session,
         seq = le64_to_cpu(h->seq);
 
         mutex_lock(&mdsc->mutex);
+        if (op == CEPH_SESSION_CLOSE)
+                __unregister_session(mdsc, session);
         /* FIXME: this ttl calculation is generous */
         session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
         mutex_unlock(&mdsc->mutex);
@@ -1990,7 +1996,6 @@ static void handle_session(struct ceph_mds_session *session,
                 break;
 
         case CEPH_SESSION_CLOSE:
-                unregister_session(mdsc, session);
                 remove_session_caps(session);
                 wake = 1; /* for good measure */
                 complete(&mdsc->session_close_waiters);
@@ -2269,7 +2274,7 @@ static void check_new_map(struct ceph_mds_client *mdsc,
                                 /* the session never opened, just close it
                                  * out now */
                                 __wake_requests(mdsc, &s->s_waiting);
-                                unregister_session(mdsc, s);
+                                __unregister_session(mdsc, s);
                         } else {
                                 /* just close it */
                                 mutex_unlock(&mdsc->mutex);
@@ -2329,24 +2334,22 @@ void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
         di->lease_session = NULL;
 }
 
-static void handle_lease(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
+static void handle_lease(struct ceph_mds_client *mdsc,
+                         struct ceph_mds_session *session,
+                         struct ceph_msg *msg)
 {
         struct super_block *sb = mdsc->client->sb;
         struct inode *inode;
-        struct ceph_mds_session *session;
         struct ceph_inode_info *ci;
         struct dentry *parent, *dentry;
         struct ceph_dentry_info *di;
-        int mds;
+        int mds = session->s_mds;
         struct ceph_mds_lease *h = msg->front.iov_base;
         struct ceph_vino vino;
         int mask;
         struct qstr dname;
         int release = 0;
 
-        if (msg->hdr.src.name.type != CEPH_ENTITY_TYPE_MDS)
-                return;
-        mds = le64_to_cpu(msg->hdr.src.name.num);
         dout("handle_lease from mds%d\n", mds);
 
         /* decode */
@@ -2360,15 +2363,6 @@ static void handle_lease(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
         if (dname.len != get_unaligned_le32(h+1))
                 goto bad;
 
-        /* find session */
-        mutex_lock(&mdsc->mutex);
-        session = __ceph_lookup_mds_session(mdsc, mds);
-        mutex_unlock(&mdsc->mutex);
-        if (!session) {
-                pr_err("handle_lease got lease but no session mds%d\n", mds);
-                return;
-        }
-
         mutex_lock(&session->s_mutex);
         session->s_seq++;
 
@@ -2437,7 +2431,6 @@ release:
 out:
         iput(inode);
         mutex_unlock(&session->s_mutex);
-        ceph_put_mds_session(session);
         return;
 
 bad:
@@ -2794,7 +2787,7 @@ void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
         for (i = 0; i < mdsc->max_sessions; i++) {
                 if (mdsc->sessions[i]) {
                         session = get_session(mdsc->sessions[i]);
-                        unregister_session(mdsc, session);
+                        __unregister_session(mdsc, session);
                         mutex_unlock(&mdsc->mutex);
                         mutex_lock(&session->s_mutex);
                         remove_session_caps(session);
@@ -2891,8 +2884,7 @@ static struct ceph_connection *con_get(struct ceph_connection *con)
         struct ceph_mds_session *s = con->private;
 
         if (get_session(s)) {
-                dout("mdsc con_get %p %d -> %d\n", s,
-                     atomic_read(&s->s_ref) - 1, atomic_read(&s->s_ref));
+                dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
                 return con;
         }
         dout("mdsc con_get %p FAIL\n", s);
@@ -2903,9 +2895,8 @@ static void con_put(struct ceph_connection *con)
 {
         struct ceph_mds_session *s = con->private;
 
-        dout("mdsc con_put %p %d -> %d\n", s, atomic_read(&s->s_ref),
-             atomic_read(&s->s_ref) - 1);
         ceph_put_mds_session(s);
+        dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref));
 }
 
 /*
@@ -2926,6 +2917,13 @@ static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
         struct ceph_mds_client *mdsc = s->s_mdsc;
         int type = le16_to_cpu(msg->hdr.type);
 
+        mutex_lock(&mdsc->mutex);
+        if (__verify_registered_session(mdsc, s) < 0) {
+                mutex_unlock(&mdsc->mutex);
+                goto out;
+        }
+        mutex_unlock(&mdsc->mutex);
+
         switch (type) {
         case CEPH_MSG_MDS_MAP:
                 ceph_mdsc_handle_map(mdsc, msg);
@@ -2937,22 +2935,23 @@ static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
                 handle_reply(s, msg);
                 break;
         case CEPH_MSG_CLIENT_REQUEST_FORWARD:
-                handle_forward(mdsc, msg);
+                handle_forward(mdsc, s, msg);
                 break;
         case CEPH_MSG_CLIENT_CAPS:
                 ceph_handle_caps(s, msg);
                 break;
         case CEPH_MSG_CLIENT_SNAP:
-                ceph_handle_snap(mdsc, msg);
+                ceph_handle_snap(mdsc, s, msg);
                 break;
         case CEPH_MSG_CLIENT_LEASE:
-                handle_lease(mdsc, msg);
+                handle_lease(mdsc, s, msg);
                 break;
 
         default:
                 pr_err("received unknown message type %d %s\n", type,
                        ceph_msg_type_name(type));
         }
+out:
         ceph_msg_put(msg);
 }
 
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 49d0c4c59d81..bf2a5f3846a4 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -713,11 +713,11 @@ static void flush_snaps(struct ceph_mds_client *mdsc)
  * directory into another realm.
  */
 void ceph_handle_snap(struct ceph_mds_client *mdsc,
+                      struct ceph_mds_session *session,
                       struct ceph_msg *msg)
 {
         struct super_block *sb = mdsc->client->sb;
-        struct ceph_mds_session *session;
-        int mds;
+        int mds = session->s_mds;
         u64 split;
         int op;
         int trace_len;
@@ -730,10 +730,6 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc,
         int i;
         int locked_rwsem = 0;
 
-        if (msg->hdr.src.name.type != CEPH_ENTITY_TYPE_MDS)
-                return;
-        mds = le64_to_cpu(msg->hdr.src.name.num);
-
         /* decode */
         if (msg->front.iov_len < sizeof(*h))
                 goto bad;
@@ -749,15 +745,6 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc,
         dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds,
              ceph_snap_op_name(op), split, trace_len);
 
-        /* find session */
-        mutex_lock(&mdsc->mutex);
-        session = __ceph_lookup_mds_session(mdsc, mds);
-        mutex_unlock(&mdsc->mutex);
-        if (!session) {
-                dout("WTF, got snap but no session for mds%d\n", mds);
-                return;
-        }
-
         mutex_lock(&session->s_mutex);
         session->s_seq++;
         mutex_unlock(&session->s_mutex);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 384f0e2e7c68..ff7aaa32736c 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -707,6 +707,7 @@ extern void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
 extern int ceph_update_snap_trace(struct ceph_mds_client *m,
                                   void *p, void *e, bool deletion);
 extern void ceph_handle_snap(struct ceph_mds_client *mdsc,
+                             struct ceph_mds_session *session,
                              struct ceph_msg *msg);
 extern void ceph_queue_cap_snap(struct ceph_inode_info *ci,
                                 struct ceph_snap_context *snapc);