Commit 16e977d5 authored Jan 31, 2017 by Vladimir Sementsov-Ogievskiy Committed by Max Reitz Feb 12, 2017

block: bdrv_invalidate_cache: invalidate children first



Current implementation invalidates firstly parent bds and then its
children. This leads to the following bug:

after incoming migration, in bdrv_invalidate_cache_all:
1. invalidate parent bds - reopen it with BDRV_O_INACTIVE cleared
2. child is not yet invalidated
3. parent check that its BDRV_O_INACTIVE is cleared
4. parent writes to child
5. assert in bdrv_co_pwritev, as BDRV_O_INACTIVE is set for child

This patch fixes it by just changing invalidate sequence: invalidate
children first.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20170131112308.54189-1-vsementsov@virtuozzo.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

parent a6baa608

block.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -3248,19 +3248,18 @@ void bdrv_invalidate_cache(BlockDriverState bs, Error *errp)
		if (!(bs->open_flags & BDRV_O_INACTIVE)) {
		return;
		}
		bs->open_flags &= ~BDRV_O_INACTIVE;

		if (bs->drv->bdrv_invalidate_cache) {
		bs->drv->bdrv_invalidate_cache(bs, &local_err);
		QLIST_FOREACH(child, &bs->children, next) {
		bdrv_invalidate_cache(child->bs, &local_err);
		if (local_err) {
		bs->open_flags \|= BDRV_O_INACTIVE;
		error_propagate(errp, local_err);
		return;
		}
		}

		QLIST_FOREACH(child, &bs->children, next) {
		bdrv_invalidate_cache(child->bs, &local_err);
		bs->open_flags &= ~BDRV_O_INACTIVE;
		if (bs->drv->bdrv_invalidate_cache) {
		bs->drv->bdrv_invalidate_cache(bs, &local_err);
		if (local_err) {
		bs->open_flags \|= BDRV_O_INACTIVE;
		error_propagate(errp, local_err);