From: Jason Dillaman <dillaman@redhat.com>
Date: Thu, 17 Sep 2020 17:05:27 +0000 (-0400)
Subject: librbd: update refresh image dispatch layer flush exclusions
X-Git-Tag: v17.0.0~1064^2~8
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=2122542a2e1bed563f633e52ac272f0ccb5a236a;p=ceph.git

librbd: update refresh image dispatch layer flush exclusions

Only flush requests coming from the refresh state machine or from the
exclusive-lock dispatch layer initializationshould be ignored. This is
because both can be initiated from the refresh state machine and
therefore deadlock.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---

diff --git a/src/librbd/io/RefreshImageDispatch.cc b/src/librbd/io/RefreshImageDispatch.cc
index 4632660ad8382..24a2038ca7ece 100644
--- a/src/librbd/io/RefreshImageDispatch.cc
+++ b/src/librbd/io/RefreshImageDispatch.cc
@@ -122,7 +122,11 @@ bool RefreshImageDispatch<I>::flush(
   auto cct = m_image_ctx->cct;
   ldout(cct, 20) << "tid=" << tid << dendl;
 
-  if (flush_source != FLUSH_SOURCE_USER) {
+  // The refresh state machine can initiate a flush and it can
+  // enable the exclusive-lock which will also attmept to flush.
+  if (flush_source == FLUSH_SOURCE_REFRESH ||
+      flush_source == FLUSH_SOURCE_EXCLUSIVE_LOCK_SKIP_REFRESH ||
+      flush_source == FLUSH_SOURCE_SHUTDOWN) {
     return false;
   }