@@ -101,6 +101,7 @@ static int bdrv_attach_child_common(BlockDriverState *child_bs,
uint64_t perm, uint64_t shared_perm,
void *opaque, BdrvChild **child,
GSList **tran, Error **errp);
+static void bdrv_remove_backing(BlockDriverState *bs, GSList **tran);
static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue
*queue, Error **errp);
@@ -3194,45 +3195,111 @@ static BdrvChildRole bdrv_backing_role(BlockDriverState *bs)
}
}
+typedef struct BdrvSetBackingNoPermState {
+ BlockDriverState *bs;
+ BlockDriverState *backing_bs;
+ BlockDriverState *old_inherits_from;
+ GSList *attach_tran;
+} BdrvSetBackingNoPermState;
+
+static void bdrv_set_backing_noperm_abort(void *opaque)
+{
+ BdrvSetBackingNoPermState *s = opaque;
+
+ if (s->backing_bs) {
+ s->backing_bs->inherits_from = s->old_inherits_from;
+ }
+
+ tran_abort(s->attach_tran);
+
+ bdrv_refresh_limits(s->bs, NULL);
+ if (s->old_inherits_from) {
+ bdrv_refresh_limits(s->old_inherits_from, NULL);
+ }
+}
+
+static void bdrv_set_backing_noperm_commit(void *opaque)
+{
+ BdrvSetBackingNoPermState *s = opaque;
+
+ tran_commit(s->attach_tran);
+}
+
+static TransactionActionDrv bdrv_set_backing_noperm_drv = {
+ .abort = bdrv_set_backing_noperm_abort,
+ .commit = bdrv_set_backing_noperm_commit,
+ .clean = g_free,
+};
+
/*
* Sets the bs->backing link of a BDS. A new reference is created; callers
* which don't need their own reference any more must call bdrv_unref().
*/
-void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
- Error **errp)
+static int bdrv_set_backing_noperm(BlockDriverState *bs,
+ BlockDriverState *backing_bs,
+ GSList **tran, Error **errp)
{
- bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
- bdrv_inherits_from_recursive(backing_hd, bs);
+ int ret = 0;
+ bool update_inherits_from = bdrv_chain_contains(bs, backing_bs) &&
+ bdrv_inherits_from_recursive(backing_bs, bs);
+ GSList *attach_tran = NULL;
+ BdrvSetBackingNoPermState *s;
if (bdrv_is_backing_chain_frozen(bs, child_bs(bs->backing), errp)) {
- return;
+ return -EPERM;
}
- if (backing_hd) {
- bdrv_ref(backing_hd);
+ if (bs->backing && backing_bs) {
+ bdrv_replace_child_safe(bs->backing, backing_bs, tran);
+ } else if (bs->backing && !backing_bs) {
+ bdrv_remove_backing(bs, tran);
+ } else if (backing_bs) {
+ assert(!bs->backing);
+ ret = bdrv_attach_child_noperm(bs, backing_bs, "backing",
+ &child_of_bds, bdrv_backing_role(bs),
+ &bs->backing, &attach_tran, errp);
+ if (ret < 0) {
+ tran_abort(attach_tran);
+ return ret;
+ }
}
- if (bs->backing) {
- /* Cannot be frozen, we checked that above */
- bdrv_unref_child(bs, bs->backing);
- bs->backing = NULL;
- }
+ s = g_new(BdrvSetBackingNoPermState, 1);
+ *s = (BdrvSetBackingNoPermState) {
+ .bs = bs,
+ .backing_bs = backing_bs,
+ .old_inherits_from = backing_bs ? backing_bs->inherits_from : NULL,
+ };
+ tran_prepend(tran, &bdrv_set_backing_noperm_drv, s);
- if (!backing_hd) {
- goto out;
+ /*
+ * If backing_bs 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 (backing_bs && update_inherits_from) {
+ backing_bs->inherits_from = bs;
}
- bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
- bdrv_backing_role(bs), errp);
- /* 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 (bs->backing && update_inherits_from) {
- backing_hd->inherits_from = bs;
+ bdrv_refresh_limits(bs, NULL);
+
+ return 0;
+}
+
+void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
+ Error **errp)
+{
+ int ret;
+ GSList *tran = NULL;
+
+ ret = bdrv_set_backing_noperm(bs, backing_hd, &tran, errp);
+ if (ret < 0) {
+ goto out;
}
+ ret = bdrv_refresh_perms(bs, errp);
out:
- bdrv_refresh_limits(bs, NULL);
+ tran_finalize(tran, ret);
}
/*
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. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- block.c | 111 +++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 89 insertions(+), 22 deletions(-)