block: move supports_backing check to bdrv_set_file_or_backing_noperm()

Move supports_backing check of bdrv_reopen_parse_backing to called
(through bdrv_set_backing_noperm()) bdrv_set_file_or_backing_noperm()
function. The check applies to general case, so it's appropriate for
bdrv_set_file_or_backing_noperm().

We have to declare backing support for two test drivers, otherwise new
check fails.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610120537.196183-7-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-06-10 15:05:34 +03:00 committed by Kevin Wolf
parent cbfdb98ce2
commit 25f78d9e2d
3 changed files with 17 additions and 14 deletions

29
block.c
View File

@ -3152,6 +3152,14 @@ static int bdrv_set_file_or_backing_noperm(BlockDriverState *parent_bs,
return -EPERM;
}
if (is_backing && !parent_bs->drv->is_filter &&
!parent_bs->drv->supports_backing)
{
error_setg(errp, "Driver '%s' of node '%s' does not support backing "
"files", parent_bs->drv->format_name, parent_bs->node_name);
return -EINVAL;
}
if (parent_bs->drv->is_filter) {
role = BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
} else if (is_backing) {
@ -4278,20 +4286,13 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
}
}
/*
* Ensure that @bs can really handle backing files, because we are
* about to give it one (or swap the existing one)
*/
if (bs->drv->is_filter) {
/* Filters always have a file or a backing child */
if (!bs->backing) {
error_setg(errp, "'%s' is a %s filter node that does not support a "
"backing child", bs->node_name, bs->drv->format_name);
return -EINVAL;
}
} else if (!bs->drv->supports_backing) {
error_setg(errp, "Driver '%s' of node '%s' does not support backing "
"files", bs->drv->format_name, bs->node_name);
if (bs->drv->is_filter && !bs->backing) {
/*
* Filters always have a file or a backing child, so we are trying to
* change wrong child
*/
error_setg(errp, "'%s' is a %s filter node that does not support a "
"backing child", bs->node_name, bs->drv->format_name);
return -EINVAL;
}

View File

@ -95,6 +95,7 @@ static int bdrv_test_change_backing_file(BlockDriverState *bs,
static BlockDriver bdrv_test = {
.format_name = "test",
.instance_size = sizeof(BDRVTestState),
.supports_backing = true,
.bdrv_close = bdrv_test_close,
.bdrv_co_preadv = bdrv_test_co_preadv,

View File

@ -41,6 +41,7 @@ static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
static BlockDriver bdrv_no_perm = {
.format_name = "no-perm",
.supports_backing = true,
.bdrv_child_perm = no_perm_default_perms,
};