From: Wen Congyang <address@hidden>
Signed-off-by: Wen Congyang <address@hidden>
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Gonglei <address@hidden>
Signed-off-by: Changlong Xie <address@hidden>
---
block.c | 8 +++---
block/quorum.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++--
include/block/block.h | 4 +++
3 files changed, 84 insertions(+), 6 deletions(-)
diff --git a/block.c b/block.c
index 68cd3b2..4bdc6b3 100644
--- a/block.c
+++ b/block.c
@@ -1176,10 +1176,10 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState
*child_bs,
return child;
}
-static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
- BlockDriverState *child_bs,
- const char *child_name,
- const BdrvChildRole *child_role)
+BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
+ BlockDriverState *child_bs,
+ const char *child_name,
+ const BdrvChildRole *child_role)
{
BdrvChild *child = bdrv_root_attach_child(child_bs, child_name,
child_role);
QLIST_INSERT_HEAD(&parent_bs->children, child, next);
diff --git a/block/quorum.c b/block/quorum.c
index da15465..2553f82 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -14,6 +14,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/cutils.h"
#include "block/block_int.h"
#include "qapi/qmp/qbool.h"
#include "qapi/qmp/qdict.h"
@@ -67,6 +68,9 @@ typedef struct QuorumVotes {
typedef struct BDRVQuorumState {
BdrvChild **children; /* children BlockDriverStates */
int num_children; /* children count */
+ uint64_t last_index; /* indicate the child role name of the last
+ * element of children array
+ */
int threshold; /* if less than threshold children reads gave the
* same result a quorum error occurs.
*/
@@ -898,9 +902,9 @@ 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;
}
@@ -964,6 +968,7 @@ static int quorum_open(BlockDriverState *bs, QDict
*options, int flags,
opened[i] = true;
}
+ s->last_index = s->num_children;
g_free(opened);
goto exit;
@@ -1020,6 +1025,72 @@ static void quorum_attach_aio_context(BlockDriverState
*bs,
}
}
+static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
+ Error **errp)
+{
+ BDRVQuorumState *s = bs->opaque;
+ BdrvChild *child;
+ char indexstr[32];
+ int ret;
+
+ assert(s->num_children <= INT_MAX / sizeof(BdrvChild *) &&
+ s->last_index <= UINT64_MAX);
+ if (s->num_children == INT_MAX / sizeof(BdrvChild *) ||
+ s->last_index == UINT64_MAX) {
+ error_setg(errp, "Too many children");
+ return;
+ }
+
+ ret = snprintf(indexstr, 32, "children.%" PRIu64, s->last_index);
+ if (ret < 0 || ret >= 32) {
+ error_setg(errp, "cannot generate child name");
+ return;
+ }
+ s->last_index++;
+
+ bdrv_drain(bs);
+
+ /* We can safely add the child now */
+ bdrv_ref(child_bs);
+ child = bdrv_attach_child(bs, child_bs, indexstr, &child_format);
+ s->children = g_renew(BdrvChild *, s->children, s->num_children + 1);
+ s->children[s->num_children++] = child;
+}
+
+static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,
+ Error **errp)
+{
+ BDRVQuorumState *s = bs->opaque;
+ int i;
+
+ for (i = 0; i < s->num_children; i++) {
+ if (s->children[i] == child) {
+ break;
+ }
+ }
+
+ /* we have checked it in bdrv_del_child() */
+ assert(i < s->num_children);
+
+ if (s->num_children <= s->threshold) {
+ error_setg(errp,
+ "The number of children cannot be lower than the vote threshold
%d",
+ s->threshold);
+ return;
+ }
+
+ /* child->name is "children.%d" */
+ assert(!strncmp(child->name, "children.", 9));
+
+ bdrv_drain(bs);
+
+ /* We can safely remove this child now */
+ memmove(&s->children[i], &s->children[i + 1],
+ (s->num_children - i - 1) * sizeof(BdrvChild *));
+ s->children = g_renew(BdrvChild *, s->children, --s->num_children);
+ bdrv_unref_child(bs, child);
+}
+
static void quorum_refresh_filename(BlockDriverState *bs, QDict *options)
{
BDRVQuorumState *s = bs->opaque;
@@ -1075,6 +1146,9 @@ 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,
};
diff --git a/include/block/block.h b/include/block/block.h
index 694ca76..52902cd 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -476,6 +476,10 @@ 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 char *child_name,
+ 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);