@@ -1079,9 +1079,9 @@ static int bdrv_fill_options(QDict **options, const char **pfilename,
return 0;
}
-static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
- BlockDriverState *child_bs,
- const BdrvChildRole *child_role)
+BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
+ BlockDriverState *child_bs,
+ const BdrvChildRole *child_role)
{
BdrvChild *child = g_new(BdrvChild, 1);
*child = (BdrvChild) {
@@ -66,6 +66,9 @@ typedef struct QuorumVotes {
typedef struct BDRVQuorumState {
BlockDriverState **bs; /* children BlockDriverStates */
int num_children; /* children count */
+ int max_children; /* The maximum children count, we need to reallocate
+ * bs if num_children grows larger than maximum.
+ */
int threshold; /* if less than threshold children reads gave the
* same result a quorum error occurs.
*/
@@ -874,9 +877,9 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
ret = -EINVAL;
goto exit;
}
- if (s->num_children < 2) {
+ if (s->num_children < 1) {
error_setg(&local_err,
- "Number of provided children must be greater than 1");
+ "Number of provided children must be 1 or more");
ret = -EINVAL;
goto exit;
}
@@ -925,6 +928,7 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
/* allocate the children BlockDriverState array */
s->bs = g_new0(BlockDriverState *, s->num_children);
opened = g_new0(bool, s->num_children);
+ s->max_children = s->num_children;
for (i = 0; i < s->num_children; i++) {
char indexstr[32];
@@ -995,6 +999,67 @@ static void quorum_attach_aio_context(BlockDriverState *bs,
}
}
+static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
+ Error **errp)
+{
+ BDRVQuorumState *s = bs->opaque;
+
+ bdrv_drain(bs);
+
+ if (s->num_children == s->max_children) {
+ if (s->max_children >= INT_MAX) {
+ error_setg(errp, "Too many children");
+ return;
+ }
+
+ s->bs = g_renew(BlockDriverState *, s->bs, s->max_children + 1);
+ s->bs[s->num_children] = NULL;
+ s->max_children++;
+ }
+
+ bdrv_ref(child_bs);
+ bdrv_attach_child(bs, child_bs, &child_format);
+ s->bs[s->num_children++] = child_bs;
+}
+
+static void quorum_del_child(BlockDriverState *bs, BlockDriverState *child_bs,
+ Error **errp)
+{
+ BDRVQuorumState *s = bs->opaque;
+ BdrvChild *child;
+ int i;
+
+ for (i = 0; i < s->num_children; i++) {
+ if (s->bs[i] == child_bs) {
+ break;
+ }
+ }
+
+ QLIST_FOREACH(child, &bs->children, next) {
+ if (child->bs == child_bs) {
+ break;
+ }
+ }
+
+ /* we have checked it in bdrv_del_child() */
+ assert(i < s->num_children && child);
+
+ if (s->num_children <= s->threshold) {
+ error_setg(errp,
+ "The number of children cannot be lower than the vote threshold %d",
+ s->threshold);
+ return;
+ }
+
+ bdrv_drain(bs);
+ /* We can safely remove this child now */
+ memmove(&s->bs[i], &s->bs[i + 1],
+ (s->num_children - i - 1) * sizeof(void *));
+ s->num_children--;
+ s->bs[s->num_children] = NULL;
+ bdrv_unref_child(bs, child);
+}
+
static void quorum_refresh_filename(BlockDriverState *bs)
{
BDRVQuorumState *s = bs->opaque;
@@ -1049,6 +1114,9 @@ static BlockDriver bdrv_quorum = {
.bdrv_detach_aio_context = quorum_detach_aio_context,
.bdrv_attach_aio_context = quorum_attach_aio_context,
+ .bdrv_add_child = quorum_add_child,
+ .bdrv_del_child = quorum_del_child,
+
.is_filter = true,
.bdrv_recurse_is_first_non_filter = quorum_recurse_is_first_non_filter,
};
@@ -514,6 +514,9 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs);
void bdrv_ref(BlockDriverState *bs);
void bdrv_unref(BlockDriverState *bs);
void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
+BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
+ BlockDriverState *child_bs,
+ const BdrvChildRole *child_role);
bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);