aboutsummaryrefslogtreecommitdiff
path: root/block/quorum.c
diff options
context:
space:
mode:
authorWen Congyang <wency@cn.fujitsu.com>2016-05-10 15:36:38 +0800
committerMax Reitz <mreitz@redhat.com>2016-05-12 15:33:23 +0200
commit98292c61bc491b660c9fa2ccbdbb35131921ea65 (patch)
tree7e27843d069383d1364c00b8e625aca56842286f /block/quorum.c
parente06018ad28874703c65dbdcfa4a5cb8aed4550ec (diff)
downloadqemu-98292c61bc491b660c9fa2ccbdbb35131921ea65.zip
qemu-98292c61bc491b660c9fa2ccbdbb35131921ea65.tar.gz
qemu-98292c61bc491b660c9fa2ccbdbb35131921ea65.tar.bz2
quorum: implement bdrv_add_child() and bdrv_del_child()
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Gonglei <arei.gonglei@huawei.com> Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com> Message-id: 1462865799-19402-3-git-send-email-xiecl.fnst@cn.fujitsu.com Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/quorum.c')
-rw-r--r--block/quorum.c78
1 files changed, 76 insertions, 2 deletions
diff --git a/block/quorum.c b/block/quorum.c
index 8f7c099..1ec3511 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 */
+ unsigned next_child_index; /* the index of the next child that should
+ * be added
+ */
int threshold; /* if less than threshold children reads gave the
* same result a quorum error occurs.
*/
@@ -883,9 +887,9 @@ 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;
}
@@ -949,6 +953,7 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
opened[i] = true;
}
+ s->next_child_index = s->num_children;
g_free(opened);
goto exit;
@@ -1005,6 +1010,72 @@ 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 *));
+ if (s->num_children == INT_MAX / sizeof(BdrvChild *) ||
+ s->next_child_index == UINT_MAX) {
+ error_setg(errp, "Too many children");
+ return;
+ }
+
+ ret = snprintf(indexstr, 32, "children.%u", s->next_child_index);
+ if (ret < 0 || ret >= 32) {
+ error_setg(errp, "cannot generate child name");
+ return;
+ }
+ s->next_child_index++;
+
+ bdrv_drained_begin(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;
+
+ bdrv_drained_end(bs);
+}
+
+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;
+ }
+
+ bdrv_drained_begin(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);
+
+ bdrv_drained_end(bs);
+}
+
static void quorum_refresh_filename(BlockDriverState *bs, QDict *options)
{
BDRVQuorumState *s = bs->opaque;
@@ -1059,6 +1130,9 @@ 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,
};