librbd: update ref count when queueing AioCompletion

If the client releases the AioCompletion while librbd is waiting
to acquire the exclusive lock, the memory associated with the
completion will be freed too early.

Fixes: #11478
Backport: hammer
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit fd7723a1e62e682ac5a5279231a9fd6f5682bf94)

diff --git a/src/librbd/ImageWatcher.cc b/src/librbd/ImageWatcher.cc
index b5f7f60f27006c835f393da754e960bdf8e1650f..486f541fbe0fa584e16cc54449cd1bbee22172d6 100644 (file)
--- a/src/librbd/ImageWatcher.cc
+++ b/src/librbd/ImageWatcher.cc
@@ -188,6 +188,8 @@ int ImageWatcher::request_lock(
     bool request_pending = !m_aio_requests.empty();
     ldout(m_image_ctx.cct, 15) << "queuing aio request: " << c
                               << dendl;
+
+    c->get();
     m_aio_requests.push_back(std::make_pair(restart_op, c));
     if (request_pending) {
       return 0;
@@ -534,6 +536,7 @@ void ImageWatcher::retry_aio_requests() {
     ldout(m_image_ctx.cct, 20) << "retrying aio request: " << iter->second
                               << dendl;
     iter->first(iter->second);
+    iter->second->put();
   }
 }