Commit fcd6a4f4 authored Sep 27, 2019 by Vladimir Sementsov-Ogievskiy Committed by John Snow Oct 17, 2019

block: reverse order for reopen commits



It's needed to fix reopening qcow2 with bitmaps to RW. Currently it
can't work, as qcow2 needs write access to file child, to mark bitmaps
in-image with IN_USE flag. But usually children goes after parents in
reopen queue and file child is still RO on qcow2 reopen commit. Reverse
reopen order to fix it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Max Reitz <mreitz@redhat.com>
Acked-by: John Snow <jsnow@redhat.com>
Message-id: 20190927122355.7344-3-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>

parent 859443b0

block.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -3486,10 +3486,16 @@ int bdrv_reopen_multiple(BlockReopenQueue bs_queue, Error *errp)
		bs_entry->perms_checked = true;
		}

		/* If we reach this point, we have success and just need to apply the
		* changes
		/*
		* If we reach this point, we have success and just need to apply the
		* changes.
		*
		* Reverse order is used to comfort qcow2 driver: on commit it need to write
		* IN_USE flag to the image, to mark bitmaps in the image as invalid. But
		* children are usually goes after parents in reopen-queue, so go from last
		* to first element.
		*/
		QTAILQ_FOREACH(bs_entry, bs_queue, entry) {
		QTAILQ_FOREACH_REVERSE(bs_entry, bs_queue, entry) {
		bdrv_reopen_commit(&bs_entry->state);
		}