diff options
Diffstat (limited to 'block.c')
-rw-r--r-- | block.c | 30 |
1 files changed, 18 insertions, 12 deletions
@@ -2243,6 +2243,13 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) } } +/* + * This function steals the reference to child_bs from the caller. + * That reference is later dropped by bdrv_root_unref_child(). + * + * On failure NULL is returned, errp is set and the reference to + * child_bs is also dropped. + */ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, const BdrvChildRole *child_role, @@ -2255,6 +2262,7 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); if (ret < 0) { bdrv_abort_perm_update(child_bs); + bdrv_unref(child_bs); return NULL; } @@ -2274,6 +2282,14 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, return child; } +/* + * This function transfers the reference to child_bs from the caller + * to parent_bs. That reference is later dropped by parent_bs on + * bdrv_close() or if someone calls bdrv_unref_child(). + * + * On failure NULL is returned, errp is set and the reference to + * child_bs is also dropped. + */ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, const char *child_name, @@ -2401,12 +2417,9 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, /* If backing_hd was already part of bs's backing chain, and * inherits_from pointed recursively to bs then let's update it to * point directly to bs (else it will become NULL). */ - if (update_inherits_from) { + if (bs->backing && update_inherits_from) { backing_hd->inherits_from = bs; } - if (!bs->backing) { - bdrv_unref(backing_hd); - } out: bdrv_refresh_limits(bs, NULL); @@ -2594,7 +2607,6 @@ BdrvChild *bdrv_open_child(const char *filename, const BdrvChildRole *child_role, bool allow_none, Error **errp) { - BdrvChild *c; BlockDriverState *bs; bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role, @@ -2603,13 +2615,7 @@ BdrvChild *bdrv_open_child(const char *filename, return NULL; } - c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp); - if (!c) { - bdrv_unref(bs); - return NULL; - } - - return c; + return bdrv_attach_child(parent, bs, bdref_key, child_role, errp); } /* TODO Future callers may need to specify parent/child_role in order for |