block: Mark bdrv_first_blk() and bdrv_is_root_node() GRAPH_RDLOCK
This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_first_blk() and bdrv_is_root_node() need to hold a reader lock
for the graph. These functions are the only functions in block-backend.c
that access the parent list of a node.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230929145157.45443-5-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/block-backend.c b/block/block-backend.c
index efe2e7c..39b5f90 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -780,11 +780,12 @@
return blk->root ? blk->root->bs : NULL;
}
-static BlockBackend *bdrv_first_blk(BlockDriverState *bs)
+static BlockBackend * GRAPH_RDLOCK bdrv_first_blk(BlockDriverState *bs)
{
BdrvChild *child;
GLOBAL_STATE_CODE();
+ assert_bdrv_graph_readable();
QLIST_FOREACH(child, &bs->parents, next_parent) {
if (child->klass == &child_root) {
@@ -812,6 +813,8 @@
BdrvChild *c;
GLOBAL_STATE_CODE();
+ assert_bdrv_graph_readable();
+
QLIST_FOREACH(c, &bs->parents, next_parent) {
if (c->klass != &child_root) {
return false;
@@ -2259,6 +2262,7 @@
if (qemu_in_coroutine()) {
bdrv_co_activate(bs, errp);
} else {
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
bdrv_activate(bs, errp);
}
}
diff --git a/block/export/export.c b/block/export/export.c
index 10316b4..a8f274e 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -83,6 +83,8 @@
uint64_t perm;
int ret;
+ GLOBAL_STATE_CODE();
+
if (!id_wellformed(export->id)) {
error_setg(errp, "Invalid block export id");
return NULL;
@@ -145,7 +147,9 @@
* access since the export could be available before migration handover.
* ctx was acquired in the caller.
*/
+ bdrv_graph_rdlock_main_loop();
bdrv_activate(bs, NULL);
+ bdrv_graph_rdunlock_main_loop();
perm = BLK_PERM_CONSISTENT_READ;
if (export->writable) {
diff --git a/block/io.c b/block/io.c
index 9e17092..5821a4d 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2330,6 +2330,7 @@
int result = 0;
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
/*
* bdrv queue is managed by record/replay,
diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c
index ca2599d..6b7d7dd 100644
--- a/block/monitor/block-hmp-cmds.c
+++ b/block/monitor/block-hmp-cmds.c
@@ -896,6 +896,8 @@
SnapshotEntry *snapshot_entry;
Error *err = NULL;
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
bs = bdrv_all_find_vmstate_bs(NULL, false, NULL, &err);
if (!bs) {
error_report_err(err);
diff --git a/block/qapi-sysemu.c b/block/qapi-sysemu.c
index ef07151..e885a64 100644
--- a/block/qapi-sysemu.c
+++ b/block/qapi-sysemu.c
@@ -279,6 +279,8 @@
BlockBackend *blk;
BlockDriverState *bs;
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
+
blk = qmp_get_blk(device, id, errp);
if (!blk) {
return;
diff --git a/block/replication.c b/block/replication.c
index 4ad3dd5..107445d 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -458,6 +458,8 @@
Error *local_err = NULL;
BackupPerf perf = { .use_copy_range = true, .max_workers = 1 };
+ GLOBAL_STATE_CODE();
+
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
s = bs->opaque;
@@ -504,12 +506,15 @@
return;
}
+ bdrv_graph_rdlock_main_loop();
secondary_disk = hidden_disk->bs->backing;
if (!secondary_disk->bs || !bdrv_has_blk(secondary_disk->bs)) {
error_setg(errp, "The secondary disk doesn't have block backend");
+ bdrv_graph_rdunlock_main_loop();
aio_context_release(aio_context);
return;
}
+ bdrv_graph_rdunlock_main_loop();
/* verify the length */
active_length = bdrv_getlength(active_disk->bs);
@@ -566,8 +571,6 @@
return;
}
- bdrv_graph_wrunlock();
-
/* start backup job now */
error_setg(&s->blocker,
"Block device is in use by internal backup job");
@@ -576,6 +579,7 @@
if (!top_bs || !bdrv_is_root_node(top_bs) ||
!check_top_bs(top_bs, bs)) {
error_setg(errp, "No top_bs or it is invalid");
+ bdrv_graph_wrunlock();
reopen_backing_file(bs, false, NULL);
aio_context_release(aio_context);
return;
@@ -583,6 +587,8 @@
bdrv_op_block_all(top_bs, s->blocker);
bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker);
+ bdrv_graph_wrunlock();
+
s->backup_job = backup_job_create(
NULL, s->secondary_disk->bs, s->hidden_disk->bs,
0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, NULL,
diff --git a/block/snapshot.c b/block/snapshot.c
index b86b5b2..633391e 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -462,9 +462,9 @@
}
-static int bdrv_all_get_snapshot_devices(bool has_devices, strList *devices,
- GList **all_bdrvs,
- Error **errp)
+static int GRAPH_RDLOCK
+bdrv_all_get_snapshot_devices(bool has_devices, strList *devices,
+ GList **all_bdrvs, Error **errp)
{
g_autoptr(GList) bdrvs = NULL;
@@ -496,7 +496,7 @@
}
-static bool bdrv_all_snapshots_includes_bs(BlockDriverState *bs)
+static bool GRAPH_RDLOCK bdrv_all_snapshots_includes_bs(BlockDriverState *bs)
{
if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
return false;
@@ -518,6 +518,7 @@
GList *iterbdrvs;
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return false;
@@ -554,6 +555,7 @@
GList *iterbdrvs;
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
@@ -595,6 +597,7 @@
GList *iterbdrvs;
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
@@ -631,6 +634,7 @@
GList *iterbdrvs;
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
@@ -673,7 +677,9 @@
{
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return -1;
@@ -715,6 +721,7 @@
GList *iterbdrvs;
GLOBAL_STATE_CODE();
+ GRAPH_RDLOCK_GUARD_MAINLOOP();
if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0) {
return NULL;
