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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
View file

@ -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,

17
blockdev.c
View file

@ -3545,8 +3545,8 @@ out:
aio_context_release(aio_context);
}
static BdrvChild *bdrv_find_child(BlockDriverState *parent_bs,
const char *child_name)
static BdrvChild * GRAPH_RDLOCK
bdrv_find_child(BlockDriverState *parent_bs, const char *child_name)
{
BdrvChild *child;
@ -3565,9 +3565,11 @@ void qmp_x_blockdev_change(const char *parent, const char *child,
BlockDriverState *parent_bs, *new_bs = NULL;
BdrvChild *p_child;
bdrv_graph_wrlock(NULL);
parent_bs = bdrv_lookup_bs(parent, parent, errp);
if (!parent_bs) {
return;
goto out;
}
if (!child == !node) {
@ -3576,7 +3578,7 @@ void qmp_x_blockdev_change(const char *parent, const char *child,
} else {
error_setg(errp, "Either child or node must be specified");
}
return;
goto out;
}
if (child) {
@ -3584,7 +3586,7 @@ void qmp_x_blockdev_change(const char *parent, const char *child,
if (!p_child) {
error_setg(errp, "Node '%s' does not have child '%s'",
parent, child);
return;
goto out;
}
bdrv_del_child(parent_bs, p_child, errp);
}
@ -3593,10 +3595,13 @@ void qmp_x_blockdev_change(const char *parent, const char *child,
new_bs = bdrv_find_node(node);
if (!new_bs) {
error_setg(errp, "Node '%s' not found", node);
return;
goto out;
}
bdrv_add_child(parent_bs, new_bs, errp);
}
out:
bdrv_graph_wrunlock();
}
BlockJobInfoList *qmp_query_block_jobs(Error **errp)

8
include/block/block-global-state.h
View file

@ -276,9 +276,11 @@ int bdrv_try_change_aio_context(BlockDriverState *bs, AioContext *ctx,
int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
Error **errp);
void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
void GRAPH_WRLOCK
bdrv_add_child(BlockDriverState *parent, BlockDriverState *child, Error **errp);
void GRAPH_WRLOCK
bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
/**
*

9
include/block/block_int-common.h
View file

@ -393,10 +393,11 @@ struct BlockDriver {
*/
int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child,
Error **errp);
void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child,
Error **errp);
void GRAPH_WRLOCK_PTR (*bdrv_add_child)(
BlockDriverState *parent, BlockDriverState *child, Error **errp);
void GRAPH_WRLOCK_PTR (*bdrv_del_child)(
BlockDriverState *parent, BdrvChild *child, Error **errp);
/**
* Informs the block driver that a permission change is intended. The