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[PATCH v2 21/21] block: Mark bdrv_add/del_child() and caller GRAPH_WRLOC
From: |
Kevin Wolf |
Subject: |
[PATCH v2 21/21] block: Mark bdrv_add/del_child() and caller GRAPH_WRLOCK |
Date: |
Mon, 11 Sep 2023 11:46:20 +0200 |
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>
---
include/block/block-global-state.h | 8 +++++---
include/block/block_int-common.h | 9 +++++----
block/quorum.c | 23 ++++++-----------------
blockdev.c | 17 +++++++++++------
4 files changed, 27 insertions(+), 30 deletions(-)
diff --git a/include/block/block-global-state.h
b/include/block/block-global-state.h
index 0f6df8f1a2..f31660c7b1 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -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);
/**
*
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 3feb67ec4a..2ca3758cb8 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -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
diff --git a/block/quorum.c b/block/quorum.c
index 620a50ba2c..05220cab7f 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -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,
diff --git a/blockdev.c b/blockdev.c
index 372eaf198c..325b7a3bef 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -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)
--
2.41.0
- [PATCH v2 13/21] block: Mark bdrv_parent_perms_conflict() and callers GRAPH_RDLOCK, (continued)
- [PATCH v2 13/21] block: Mark bdrv_parent_perms_conflict() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/09/11
- [PATCH v2 14/21] block: Mark bdrv_get_cumulative_perm() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/09/11
- [PATCH v2 17/21] block: Take graph rdlock in bdrv_drop_intermediate(), Kevin Wolf, 2023/09/11
- [PATCH v2 15/21] block: Mark bdrv_child_perm() GRAPH_RDLOCK, Kevin Wolf, 2023/09/11
- [PATCH v2 16/21] block: Mark bdrv_parent_cb_change_media() GRAPH_RDLOCK, Kevin Wolf, 2023/09/11
- [PATCH v2 18/21] block: Take graph rdlock in bdrv_change_aio_context(), Kevin Wolf, 2023/09/11
- [PATCH v2 19/21] block: Mark bdrv_root_unref_child() GRAPH_WRLOCK, Kevin Wolf, 2023/09/11
- [PATCH v2 20/21] block: Mark bdrv_unref_child() GRAPH_WRLOCK, Kevin Wolf, 2023/09/11
- [PATCH v2 21/21] block: Mark bdrv_add/del_child() and caller GRAPH_WRLOCK,
Kevin Wolf <=
- Re: [PATCH v2 00/21] Graph locking part 4 (node management), Stefan Hajnoczi, 2023/09/12