block: Use bdrv_cow_child() in bdrv_co_truncate()

The condition modified here is not about potentially filtered children,
but only about COW sources (i.e. traditional backing files).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2020-06-18 17:39:28 +02:00 committed by Kevin Wolf
parent dcf3f9b268
commit 23b93525a2
1 changed files with 4 additions and 3 deletions

View File

@ -3310,7 +3310,7 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
Error **errp)
{
BlockDriverState *bs = child->bs;
BdrvChild *filtered;
BdrvChild *filtered, *backing;
BlockDriver *drv = bs->drv;
BdrvTrackedRequest req;
int64_t old_size, new_bytes;
@ -3363,6 +3363,7 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
}
filtered = bdrv_filter_child(bs);
backing = bdrv_cow_child(bs);
/*
* If the image has a backing file that is large enough that it would
@ -3374,10 +3375,10 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
* backing file, taking care of keeping things consistent with that backing
* file is the user's responsibility.
*/
if (new_bytes && bs->backing) {
if (new_bytes && backing) {
int64_t backing_len;
backing_len = bdrv_getlength(backing_bs(bs));
backing_len = bdrv_getlength(backing->bs);
if (backing_len < 0) {
ret = backing_len;
error_setg_errno(errp, -ret, "Could not get backing file size");