diff options
| -rw-r--r-- | block.c | 60 |
1 files changed, 39 insertions, 21 deletions
@@ -2612,12 +2612,15 @@ static void bdrv_replace_child_noperm(BdrvChild *child, * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this * function uses bdrv_set_perm() to update the permissions according to the new * reference that @new_bs gets. + * + * Callers must ensure that child->frozen is false. */ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) { BlockDriverState *old_bs = child->bs; uint64_t perm, shared_perm; + /* Asserts that child->frozen == false */ bdrv_replace_child_noperm(child, new_bs); /* @@ -2778,6 +2781,7 @@ static void bdrv_detach_child(BdrvChild *child) g_free(child); } +/* Callers must ensure that child->frozen is false. */ void bdrv_root_unref_child(BdrvChild *child) { BlockDriverState *child_bs; @@ -2815,6 +2819,7 @@ static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child) } } +/* Callers must ensure that child->frozen is false. */ void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) { if (child == NULL) { @@ -2881,6 +2886,7 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, } if (bs->backing) { + /* Cannot be frozen, we checked that above */ bdrv_unref_child(bs, bs->backing); bs->backing = NULL; } @@ -4387,6 +4393,7 @@ static void bdrv_close(BlockDriverState *bs) if (bs->drv) { if (bs->drv->bdrv_close) { + /* Must unfreeze all children, so bdrv_unref_child() works */ bs->drv->bdrv_close(bs); } bs->drv = NULL; @@ -4762,20 +4769,22 @@ BlockDriverState *bdrv_find_base(BlockDriverState *bs) } /* - * Return true if at least one of the backing links between @bs and - * @base is frozen. @errp is set if that's the case. + * Return true if at least one of the COW (backing) and filter links + * between @bs and @base is frozen. @errp is set if that's the case. * @base must be reachable from @bs, or NULL. */ bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base, Error **errp) { BlockDriverState *i; + BdrvChild *child; - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing && i->backing->frozen) { + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + + if (child && child->frozen) { error_setg(errp, "Cannot change '%s' link from '%s' to '%s'", - i->backing->name, i->node_name, - backing_bs(i)->node_name); + child->name, i->node_name, child->bs->node_name); return true; } } @@ -4784,7 +4793,7 @@ bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base, } /* - * Freeze all backing links between @bs and @base. + * Freeze all COW (backing) and filter links between @bs and @base. * If any of the links is already frozen the operation is aborted and * none of the links are modified. * @base must be reachable from @bs, or NULL. @@ -4794,22 +4803,25 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base, Error **errp) { BlockDriverState *i; + BdrvChild *child; if (bdrv_is_backing_chain_frozen(bs, base, errp)) { return -EPERM; } - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing && backing_bs(i)->never_freeze) { + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + if (child && child->bs->never_freeze) { error_setg(errp, "Cannot freeze '%s' link to '%s'", - i->backing->name, backing_bs(i)->node_name); + child->name, child->bs->node_name); return -EPERM; } } - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing) { - i->backing->frozen = true; + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + if (child) { + child->frozen = true; } } @@ -4817,18 +4829,21 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base, } /* - * Unfreeze all backing links between @bs and @base. The caller must - * ensure that all links are frozen before using this function. + * Unfreeze all COW (backing) and filter links between @bs and @base. + * The caller must ensure that all links are frozen before using this + * function. * @base must be reachable from @bs, or NULL. */ void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base) { BlockDriverState *i; + BdrvChild *child; - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing) { - assert(i->backing->frozen); - i->backing->frozen = false; + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + if (child) { + assert(child->frozen); + child->frozen = false; } } } @@ -4931,8 +4946,11 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, } } - /* Do the actual switch in the in-memory graph. - * Completes bdrv_check_update_perm() transaction internally. */ + /* + * Do the actual switch in the in-memory graph. + * Completes bdrv_check_update_perm() transaction internally. + * c->frozen is false, we have checked that above. + */ bdrv_ref(base); bdrv_replace_child(c, base); bdrv_unref(top); |