block: add bdrv_set_backing_noperm() transaction action
Split out no-perm part of bdrv_set_backing_hd() as a separate transaction action. Note the in case of existing BdrvChild we reuse it, not recreate, just to do less actions. We don't need to create extra reference to backing_hd as we don't lose it in bdrv_attach_child(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-29-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
parent
1e4c797c75
commit
160333e1fe
54
block.c
54
block.c
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@ -92,6 +92,8 @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs,
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BdrvChild **child,
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BdrvChild **child,
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Transaction *tran,
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Transaction *tran,
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Error **errp);
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Error **errp);
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static void bdrv_remove_filter_or_cow_child(BlockDriverState *bs,
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Transaction *tran);
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static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue
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static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue
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*queue, Error **errp);
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*queue, Error **errp);
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@ -3322,8 +3324,9 @@ static BdrvChildRole bdrv_backing_role(BlockDriverState *bs)
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* Sets the bs->backing link of a BDS. A new reference is created; callers
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* Sets the bs->backing link of a BDS. A new reference is created; callers
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* which don't need their own reference any more must call bdrv_unref().
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* which don't need their own reference any more must call bdrv_unref().
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*/
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*/
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int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
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static int bdrv_set_backing_noperm(BlockDriverState *bs,
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Error **errp)
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BlockDriverState *backing_hd,
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Transaction *tran, Error **errp)
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{
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{
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int ret = 0;
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int ret = 0;
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bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
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bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
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@ -3333,36 +3336,53 @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
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return -EPERM;
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return -EPERM;
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}
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}
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if (backing_hd) {
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bdrv_ref(backing_hd);
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}
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if (bs->backing) {
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if (bs->backing) {
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/* Cannot be frozen, we checked that above */
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/* Cannot be frozen, we checked that above */
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bdrv_unref_child(bs, bs->backing);
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bdrv_unset_inherits_from(bs, bs->backing, tran);
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bs->backing = NULL;
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bdrv_remove_filter_or_cow_child(bs, tran);
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}
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}
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if (!backing_hd) {
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if (!backing_hd) {
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goto out;
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goto out;
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}
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}
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bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
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ret = bdrv_attach_child_noperm(bs, backing_hd, "backing",
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bdrv_backing_role(bs), errp);
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&child_of_bds, bdrv_backing_role(bs),
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if (!bs->backing) {
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&bs->backing, tran, errp);
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ret = -EPERM;
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if (ret < 0) {
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goto out;
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return ret;
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}
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}
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/* If backing_hd was already part of bs's backing chain, and
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/*
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* If backing_hd was already part of bs's backing chain, and
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* inherits_from pointed recursively to bs then let's update it to
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* inherits_from pointed recursively to bs then let's update it to
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* point directly to bs (else it will become NULL). */
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* point directly to bs (else it will become NULL).
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*/
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if (update_inherits_from) {
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if (update_inherits_from) {
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backing_hd->inherits_from = bs;
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bdrv_set_inherits_from(backing_hd, bs, tran);
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}
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}
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out:
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out:
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bdrv_refresh_limits(bs, NULL, NULL);
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bdrv_refresh_limits(bs, tran, NULL);
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return 0;
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}
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int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
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Error **errp)
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{
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int ret;
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Transaction *tran = tran_new();
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ret = bdrv_set_backing_noperm(bs, backing_hd, tran, errp);
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if (ret < 0) {
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goto out;
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}
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ret = bdrv_refresh_perms(bs, errp);
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out:
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tran_finalize(tran, ret);
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return ret;
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return ret;
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}
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}
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