ceph: rename get_session and switch to use ceph_get_mds_session

Just in case the session's refcount reach 0 and is releasing, and
if we get the session without checking it, we may encounter kernel
crash.

Rename get_session to ceph_get_mds_session and make it global.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index aba7a56..f7c9a56 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -538,7 +538,7 @@ const char *ceph_session_state_name(int s)
        }
 }
 
-static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
+struct ceph_mds_session *ceph_get_mds_session(struct ceph_mds_session *s)
 {
        if (refcount_inc_not_zero(&s->s_ref)) {
                dout("mdsc get_session %p %d -> %d\n", s,
@@ -569,7 +569,7 @@ struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
 {
        if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
                return NULL;
-       return get_session(mdsc->sessions[mds]);
+       return ceph_get_mds_session(mdsc->sessions[mds]);
 }
 
 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
@@ -1979,7 +1979,7 @@ void ceph_flush_cap_releases(struct ceph_mds_client *mdsc,
        if (mdsc->stopping)
                return;
 
-       get_session(session);
+       ceph_get_mds_session(session);
        if (queue_work(mdsc->fsc->cap_wq,
                       &session->s_cap_release_work)) {
                dout("cap release work queued\n");
@@ -2615,7 +2615,7 @@ static void __do_request(struct ceph_mds_client *mdsc,
                        goto finish;
                }
        }
-       req->r_session = get_session(session);
+       req->r_session = ceph_get_mds_session(session);
 
        dout("do_request mds%d session %p state %s\n", mds, session,
             ceph_session_state_name(session->s_state));
@@ -3139,7 +3139,7 @@ static void handle_session(struct ceph_mds_session *session,
 
        mutex_lock(&mdsc->mutex);
        if (op == CEPH_SESSION_CLOSE) {
-               get_session(session);
+               ceph_get_mds_session(session);
                __unregister_session(mdsc, session);
        }
        /* FIXME: this ttl calculation is generous */
@@ -3801,7 +3801,7 @@ static void check_new_map(struct ceph_mds_client *mdsc,
 
                if (i >= newmap->possible_max_rank) {
                        /* force close session for stopped mds */
-                       get_session(s);
+                       ceph_get_mds_session(s);
                        __unregister_session(mdsc, s);
                        __wake_requests(mdsc, &s->s_waiting);
                        mutex_unlock(&mdsc->mutex);
@@ -4402,7 +4402,7 @@ void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
        mutex_lock(&mdsc->mutex);
        for (i = 0; i < mdsc->max_sessions; i++) {
                if (mdsc->sessions[i]) {
-                       session = get_session(mdsc->sessions[i]);
+                       session = ceph_get_mds_session(mdsc->sessions[i]);
                        __unregister_session(mdsc, session);
                        mutex_unlock(&mdsc->mutex);
                        mutex_lock(&session->s_mutex);
@@ -4630,7 +4630,7 @@ static struct ceph_connection *con_get(struct ceph_connection *con)
 {
        struct ceph_mds_session *s = con->private;
 
-       if (get_session(s))
+       if (ceph_get_mds_session(s))
                return con;
        return NULL;
 }

diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index fe085e0..c021df5 100644 (file)
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -452,15 +452,10 @@ extern const char *ceph_mds_op_name(int op);
 extern struct ceph_mds_session *
 __ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
 
-static inline struct ceph_mds_session *
-ceph_get_mds_session(struct ceph_mds_session *s)
-{
-       refcount_inc(&s->s_ref);
-       return s;
-}
-
 extern const char *ceph_session_state_name(int s);
 
+extern struct ceph_mds_session *
+ceph_get_mds_session(struct ceph_mds_session *s);
 extern void ceph_put_mds_session(struct ceph_mds_session *s);
 
 extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,