[Cluster-devel] [PATCH dlm/next 1/2] fs: dlm: fix race in mhandle deletion
Alexander Aring
aahringo at redhat.com
Fri Jun 11 16:55:40 UTC 2021
This patch fixes a race between mhandle deletion in case of receiving an
acknowledge and flush of all pending mhandle in cases of an timeout or
resetting node states.
Fixes: 489d8e559c65 ("fs: dlm: add reliable connection if reconnect")
Reported-by: Guillaume Nault <gnault at redhat.com>
Signed-off-by: Alexander Aring <aahringo at redhat.com>
---
fs/dlm/midcomms.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index 7d217234b697..92f95ee7003a 100644
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -287,6 +287,14 @@ static void dlm_mhandle_release(struct rcu_head *rcu)
kfree(mh);
}
+static void dlm_mhandle_delete(struct midcomms_node *node,
+ struct dlm_mhandle *mh)
+{
+ list_del_rcu(&mh->list);
+ atomic_dec(&node->send_queue_cnt);
+ call_rcu(&mh->rcu, dlm_mhandle_release);
+}
+
static void dlm_send_queue_flush(struct midcomms_node *node)
{
struct dlm_mhandle *mh;
@@ -294,15 +302,11 @@ static void dlm_send_queue_flush(struct midcomms_node *node)
pr_debug("flush midcomms send queue of node %d\n", node->nodeid);
rcu_read_lock();
+ spin_lock(&node->send_queue_lock);
list_for_each_entry_rcu(mh, &node->send_queue, list) {
- spin_lock(&node->send_queue_lock);
- list_del_rcu(&mh->list);
- spin_unlock(&node->send_queue_lock);
-
- atomic_dec(&node->send_queue_cnt);
-
- call_rcu(&mh->rcu, dlm_mhandle_release);
+ dlm_mhandle_delete(node, mh);
}
+ spin_unlock(&node->send_queue_lock);
rcu_read_unlock();
}
@@ -424,21 +428,24 @@ static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
rcu_read_lock();
list_for_each_entry_rcu(mh, &node->send_queue, list) {
if (before(mh->seq, seq)) {
- spin_lock(&node->send_queue_lock);
- list_del_rcu(&mh->list);
- spin_unlock(&node->send_queue_lock);
-
- atomic_dec(&node->send_queue_cnt);
-
if (mh->ack_rcv)
mh->ack_rcv(node);
+ } else {
+ /* send queue should be ordered */
+ break;
+ }
+ }
- call_rcu(&mh->rcu, dlm_mhandle_release);
+ spin_lock(&node->send_queue_lock);
+ list_for_each_entry_rcu(mh, &node->send_queue, list) {
+ if (before(mh->seq, seq)) {
+ dlm_mhandle_delete(node, mh);
} else {
/* send queue should be ordered */
break;
}
}
+ spin_unlock(&node->send_queue_lock);
rcu_read_unlock();
}
--
2.26.3
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