PendingReleaseNotes: add rbd_diff_iterate2 note

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit 40e8813e9c705838eee42c98de717b20851aed72)

Conflicts:
	PendingReleaseNotes [ moved to >=18.2.2 section ]

diff --git a/PendingReleaseNotes b/PendingReleaseNotes
index 7526f34f194a366fa0993470e7f65496b52da821..d7a8ed26d25bccd6d4e9158c23376178b07b2100 100644 (file)
--- a/PendingReleaseNotes
+++ b/PendingReleaseNotes
@@ -1,3 +1,12 @@
+>=18.2.2
+--------
+
+* RBD: When diffing against the beginning of time (`fromsnapname == NULL`) in
+  fast-diff mode (`whole_object == true` with `fast-diff` image feature enabled
+  and valid), diff-iterate is now guaranteed to execute locally if exclusive
+  lock is available.  This brings a dramatic performance improvement for QEMU
+  live disk synchronization and backup use cases.
+
 >=19.0.0
 
 * The cephfs-shell utility is now packaged for RHEL 9 / CentOS 9 as required