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block: Mark bdrv_add/del_child() and caller GRAPH_WRLOCK

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The functions read the parents list in the generic block layer, so we
need to hold the graph lock already there. The BlockDriver
implementations actually modify the graph, so it has to be a writer
lock.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230911094620.45040-22-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2023-09-11 11:46:20 +02:00
parent 32a8aba37e
commit 9def6082cf
4 changed files with 27 additions and 30 deletions
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23
block/quorum.c
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@ -1066,8 +1066,8 @@ static void quorum_close(BlockDriverState *bs)
g_free(s->children);
}
static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
Error **errp)
static void GRAPH_WRLOCK
quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs, Error **errp)
{
BDRVQuorumState *s = bs->opaque;
BdrvChild *child;
@ -1093,29 +1093,22 @@ static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
}
s->next_child_index++;
bdrv_drained_begin(bs);
/* We can safely add the child now */
bdrv_ref(child_bs);
bdrv_graph_wrlock(child_bs);
child = bdrv_attach_child(bs, child_bs, indexstr, &child_of_bds,
BDRV_CHILD_DATA, errp);
bdrv_graph_wrunlock();
if (child == NULL) {
s->next_child_index--;
goto out;
return;
}
s->children = g_renew(BdrvChild *, s->children, s->num_children + 1);
s->children[s->num_children++] = child;
quorum_refresh_flags(bs);
out:
bdrv_drained_end(bs);
}
static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,
Error **errp)
static void GRAPH_WRLOCK
quorum_del_child(BlockDriverState *bs, BdrvChild *child, Error **errp)
{
BDRVQuorumState *s = bs->opaque;
char indexstr[INDEXSTR_LEN];
@ -1145,18 +1138,14 @@ static void quorum_del_child(BlockDriverState *bs, BdrvChild *child,
s->next_child_index--;
}
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_graph_wrlock(NULL);
bdrv_unref_child(bs, child);
bdrv_graph_wrunlock();
quorum_refresh_flags(bs);
bdrv_drained_end(bs);
}
static void quorum_gather_child_options(BlockDriverState *bs, QDict *target,