block/quorum.c: stable children names

If we remove the child with the highest index from the quorum,
decrement s->next_child_index. This way we get stable children
names as long as we only remove the last child.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Fixes: https://bugs.launchpad.net/bugs/1881231
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <5d5f930424c1c770754041aa8ad6421dc4e2b58e.1596536719.git.lukasstraub2@web.de>
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Lukas Straub 2020-08-04 12:46:42 +02:00 committed by Max Reitz
parent 7cc002a06c
commit 5eb9a3c7b0

View file

@ -29,6 +29,8 @@
#define HASH_LENGTH 32
#define INDEXSTR_LEN 32
#define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold"
#define QUORUM_OPT_BLKVERIFY "blkverify"
#define QUORUM_OPT_REWRITE "rewrite-corrupted"
@ -970,9 +972,9 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
opened = g_new0(bool, s->num_children);
for (i = 0; i < s->num_children; i++) {
char indexstr[32];
ret = snprintf(indexstr, 32, "children.%d", i);
assert(ret < 32);
char indexstr[INDEXSTR_LEN];
ret = snprintf(indexstr, INDEXSTR_LEN, "children.%d", i);
assert(ret < INDEXSTR_LEN);
s->children[i] = bdrv_open_child(NULL, options, indexstr, bs,
&child_of_bds, BDRV_CHILD_DATA, false,
@ -1024,7 +1026,7 @@ static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
{
BDRVQuorumState *s = bs->opaque;
BdrvChild *child;
char indexstr[32];
char indexstr[INDEXSTR_LEN];
int ret;
if (s->is_blkverify) {
@ -1039,8 +1041,8 @@ static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
return;
}
ret = snprintf(indexstr, 32, "children.%u", s->next_child_index);
if (ret < 0 || ret >= 32) {
ret = snprintf(indexstr, INDEXSTR_LEN, "children.%u", s->next_child_index);
if (ret < 0 || ret >= INDEXSTR_LEN) {
error_setg(errp, "cannot generate child name");
return;
}
@ -1068,6 +1070,7 @@ static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,
Error **errp)
{
BDRVQuorumState *s = bs->opaque;
char indexstr[INDEXSTR_LEN];
int i;
for (i = 0; i < s->num_children; i++) {
@ -1089,6 +1092,11 @@ static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,
/* We know now that num_children > threshold, so blkverify must be false */
assert(!s->is_blkverify);
snprintf(indexstr, INDEXSTR_LEN, "children.%u", s->next_child_index - 1);
if (!strncmp(child->name, indexstr, INDEXSTR_LEN)) {
s->next_child_index--;
}
bdrv_drained_begin(bs);
/* We can safely remove this child now */