block: Add bdrv_recurse_can_replace()

After a couple of follow-up patches, this function will replace
bdrv_recurse_is_first_non_filter() in check_to_replace_node().

bdrv_recurse_is_first_non_filter() is both not sufficiently specific for
check_to_replace_node() (it allows cases that should not be allowed,
like replacing child nodes of quorum with dissenting data that have more
parents than just quorum), and it is too restrictive (it is perfectly
fine to replace filters).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200218103454.296704-7-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2020-02-18 11:34:41 +01:00 committed by Kevin Wolf
parent 37a3791b38
commit 5d69b5ab85
2 changed files with 48 additions and 0 deletions

View file

@ -102,6 +102,13 @@ struct BlockDriver {
*/
bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs,
BlockDriverState *candidate);
/*
* Return true if @to_replace can be replaced by a BDS with the
* same data as @bs without it affecting @bs's behavior (that is,
* without it being visible to @bs's parents).
*/
bool (*bdrv_recurse_can_replace)(BlockDriverState *bs,
BlockDriverState *to_replace);
int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
int (*bdrv_probe_device)(const char *filename);
@ -1263,6 +1270,9 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared);
bool bdrv_recurse_can_replace(BlockDriverState *bs,
BlockDriverState *to_replace);
/*
* Default implementation for drivers to pass bdrv_co_block_status() to
* their file.