ceph: handle race between cap reconnect and cap release
When a cap get released while composing the cap reconnect message.
We should skip queuing the release message if the cap hasn't been
added to the cap reconnect message.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 4a93d69..6d953ab 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -444,6 +444,7 @@
INIT_LIST_HEAD(&s->s_waiting);
INIT_LIST_HEAD(&s->s_unsafe);
s->s_num_cap_releases = 0;
+ s->s_cap_reconnect = 0;
s->s_cap_iterator = NULL;
INIT_LIST_HEAD(&s->s_cap_releases);
INIT_LIST_HEAD(&s->s_cap_releases_done);
@@ -1415,7 +1416,6 @@
unsigned num;
dout("discard_cap_releases mds%d\n", session->s_mds);
- spin_lock(&session->s_cap_lock);
/* zero out the in-progress message */
msg = list_first_entry(&session->s_cap_releases,
@@ -1442,8 +1442,6 @@
msg->front.iov_len = sizeof(*head);
list_add(&msg->list_head, &session->s_cap_releases);
}
-
- spin_unlock(&session->s_cap_lock);
}
/*
@@ -2488,6 +2486,7 @@
cap->seq = 0; /* reset cap seq */
cap->issue_seq = 0; /* and issue_seq */
cap->mseq = 0; /* and migrate_seq */
+ cap->cap_gen = cap->session->s_cap_gen;
if (recon_state->flock) {
rec.v2.cap_id = cpu_to_le64(cap->cap_id);
@@ -2611,8 +2610,20 @@
dout("session %p state %s\n", session,
session_state_name(session->s_state));
+ spin_lock(&session->s_gen_ttl_lock);
+ session->s_cap_gen++;
+ spin_unlock(&session->s_gen_ttl_lock);
+
+ spin_lock(&session->s_cap_lock);
+ /*
+ * notify __ceph_remove_cap() that we are composing cap reconnect.
+ * If a cap get released before being added to the cap reconnect,
+ * __ceph_remove_cap() should skip queuing cap release.
+ */
+ session->s_cap_reconnect = 1;
/* drop old cap expires; we're about to reestablish that state */
discard_cap_releases(mdsc, session);
+ spin_unlock(&session->s_cap_lock);
/* traverse this session's caps */
s_nr_caps = session->s_nr_caps;
@@ -2627,6 +2638,10 @@
if (err < 0)
goto fail;
+ spin_lock(&session->s_cap_lock);
+ session->s_cap_reconnect = 0;
+ spin_unlock(&session->s_cap_lock);
+
/*
* snaprealms. we provide mds with the ino, seq (version), and
* parent for all of our realms. If the mds has any newer info,