ceph: fix locking for waking session requests after reconnect
The session->s_waiting list is protected by mdsc->mutex, not s_mutex. This
was causing (rare) s_waiting list corruption.
Fix errors paths too, while we're here. A more thorough cleanup of this
function is coming soon.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 60a9a4a..eccc0ec 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2136,7 +2136,7 @@
struct ceph_mds_session *session = NULL;
struct ceph_msg *reply;
struct rb_node *p;
- int err;
+ int err = -ENOMEM;
struct ceph_pagelist *pagelist;
pr_info("reconnect to recovering mds%d\n", mds);
@@ -2185,7 +2185,7 @@
goto fail;
err = iterate_session_caps(session, encode_caps_cb, pagelist);
if (err < 0)
- goto out;
+ goto fail;
/*
* snaprealms. we provide mds with the ino, seq (version), and
@@ -2213,28 +2213,31 @@
reply->nr_pages = calc_pages_for(0, pagelist->length);
ceph_con_send(&session->s_con, reply);
- if (session) {
- session->s_state = CEPH_MDS_SESSION_OPEN;
- __wake_requests(mdsc, &session->s_waiting);
- }
+ session->s_state = CEPH_MDS_SESSION_OPEN;
+ mutex_unlock(&session->s_mutex);
-out:
+ mutex_lock(&mdsc->mutex);
+ __wake_requests(mdsc, &session->s_waiting);
+ mutex_unlock(&mdsc->mutex);
+
+ ceph_put_mds_session(session);
+
up_read(&mdsc->snap_rwsem);
- if (session) {
- mutex_unlock(&session->s_mutex);
- ceph_put_mds_session(session);
- }
mutex_lock(&mdsc->mutex);
return;
fail:
ceph_msg_put(reply);
+ up_read(&mdsc->snap_rwsem);
+ mutex_unlock(&session->s_mutex);
+ ceph_put_mds_session(session);
fail_nomsg:
ceph_pagelist_release(pagelist);
kfree(pagelist);
fail_nopagelist:
- pr_err("ENOMEM preparing reconnect for mds%d\n", mds);
- goto out;
+ pr_err("error %d preparing reconnect for mds%d\n", err, mds);
+ mutex_lock(&mdsc->mutex);
+ return;
}