block: Default .bdrv_child_perm() for filter drivers

Most filters need permissions related to read and write for their
children, but only if the node has a parent that wants to use the same
operation on the filter. The same is true for resize.

This adds a default implementation that simply forwards all necessary
permissions to all children of the node and leaves the other permissions
unchanged.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-12-15 11:27:32 +01:00
parent 33a610c398
commit 6a1b9ee152
2 changed files with 31 additions and 0 deletions

View file

@ -872,6 +872,14 @@ void bdrv_child_abort_perm_update(BdrvChild *c);
int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
Error **errp);
/* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
* block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to
* all children */
void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared);
const char *bdrv_get_parent_name(const BlockDriverState *bs);
void blk_dev_change_media_cb(BlockBackend *blk, bool load);