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[PATCH 09/11] block: move drain out of bdrv_change_aio_context()
|
From: |
Fiona Ebner |
|
Subject: |
[PATCH 09/11] block: move drain out of bdrv_change_aio_context() |
|
Date: |
Thu, 8 May 2025 16:09:34 +0200 |
While bdrv_drained_begin() is now marked as GRAPH_UNLOCKED, TSA is not
able to catch a remaining instance where the function is called with
the graph lock held in bdrv_change_aio_context(). This is because the
call is preceded by a bdrv_graph_rdunlock_main_loop(), but for callers
that hold the exclusive lock that does not actually release the lock.
In combination with block-stream, there is a deadlock that can happen
because of this [0]. In particular, it can happen that
main thread IO thread
1. acquires write lock
in blk_co_do_preadv_part():
2. have non-zero blk->in_flight
3. try to acquire read lock
4. begin drain
Steps 3 and 4 might be switched. Draining will poll and get stuck,
because it will see the non-zero in_flight counter. But the IO thread
will not make any progress either, because it cannot acquire the read
lock.
More granular draining is not trivially possible, because
bdrv_change_aio_context() can recursively call itself e.g. via
bdrv_child_change_aio_context().
[0]:
https://lore.kernel.org/qemu-devel/73839c04-7616-407e-b057-80ca69e63f51@virtuozzo.com/
Reported-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
block.c | 91 ++++++++++++++++++++----------
block/backup.c | 2 +
block/blklogwrites.c | 4 ++
block/blkverify.c | 2 +
block/block-backend.c | 4 ++
block/commit.c | 4 ++
block/mirror.c | 5 ++
block/qcow2.c | 2 +
block/quorum.c | 4 ++
block/replication.c | 7 +++
block/snapshot.c | 2 +
block/stream.c | 10 ++--
block/vmdk.c | 10 ++++
blockdev.c | 17 ++++--
blockjob.c | 6 ++
include/block/block-global-state.h | 8 ++-
tests/unit/test-bdrv-drain.c | 18 ++++++
tests/unit/test-bdrv-graph-mod.c | 10 ++++
18 files changed, 164 insertions(+), 42 deletions(-)
diff --git a/block.c b/block.c
index 10052027cd..d84ac2f394 100644
--- a/block.c
+++ b/block.c
@@ -1720,12 +1720,14 @@ bdrv_open_driver(BlockDriverState *bs, BlockDriver
*drv, const char *node_name,
open_failed:
bs->drv = NULL;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
if (bs->file != NULL) {
bdrv_unref_child(bs, bs->file);
assert(!bs->file);
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
g_free(bs->opaque);
bs->opaque = NULL;
@@ -3027,7 +3029,8 @@ static void GRAPH_WRLOCK
bdrv_attach_child_common_abort(void *opaque)
bdrv_replace_child_noperm(s->child, NULL);
if (bdrv_get_aio_context(bs) != s->old_child_ctx) {
- bdrv_try_change_aio_context(bs, s->old_child_ctx, NULL, &error_abort);
+ bdrv_try_change_aio_context_locked(bs, s->old_child_ctx, NULL,
+ &error_abort);
}
if (bdrv_child_get_parent_aio_context(s->child) != s->old_parent_ctx) {
@@ -3112,8 +3115,8 @@ bdrv_attach_child_common(BlockDriverState *child_bs,
parent_ctx = bdrv_child_get_parent_aio_context(new_child);
if (child_ctx != parent_ctx) {
Error *local_err = NULL;
- int ret = bdrv_try_change_aio_context(child_bs, parent_ctx, NULL,
- &local_err);
+ int ret = bdrv_try_change_aio_context_locked(child_bs, parent_ctx,
NULL,
+ &local_err);
if (ret < 0 && child_class->change_aio_ctx) {
Transaction *aio_ctx_tran = tran_new();
@@ -3314,8 +3317,8 @@ void bdrv_root_unref_child(BdrvChild *child)
* When the parent requiring a non-default AioContext is removed, the
* node moves back to the main AioContext
*/
- bdrv_try_change_aio_context(child_bs, qemu_get_aio_context(), NULL,
- NULL);
+ bdrv_try_change_aio_context_locked(child_bs, qemu_get_aio_context(),
+ NULL, NULL);
}
bdrv_schedule_unref(child_bs);
@@ -3584,11 +3587,11 @@ int bdrv_set_backing_hd(BlockDriverState *bs,
BlockDriverState *backing_hd,
bdrv_graph_rdunlock_main_loop();
bdrv_ref(drain_bs);
- bdrv_drained_begin(drain_bs);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
ret = bdrv_set_backing_hd_drained(bs, backing_hd, errp);
bdrv_graph_wrunlock();
- bdrv_drained_end(drain_bs);
+ bdrv_drain_all_end();
bdrv_unref(drain_bs);
return ret;
@@ -3780,10 +3783,12 @@ static BdrvChild *bdrv_open_child_common(const char
*filename,
return NULL;
}
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
child = bdrv_attach_child(parent, bs, bdref_key, child_class, child_role,
errp);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
return child;
}
@@ -4805,20 +4810,19 @@ bdrv_reopen_parse_file_or_backing(BDRVReopenState
*reopen_state,
if (old_child_bs) {
bdrv_ref(old_child_bs);
- bdrv_graph_rdunlock_main_loop();
- bdrv_drained_begin(old_child_bs);
- } else {
- bdrv_graph_rdunlock_main_loop();
}
+
+ bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
ret = bdrv_set_file_or_backing_noperm(bs, new_child_bs, is_backing,
tran, errp);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
if (old_child_bs) {
- bdrv_drained_end(old_child_bs);
bdrv_unref(old_child_bs);
}
@@ -5160,6 +5164,7 @@ static void bdrv_close(BlockDriverState *bs)
bs->drv = NULL;
}
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
bdrv_unref_child(bs, child);
@@ -5168,6 +5173,7 @@ static void bdrv_close(BlockDriverState *bs)
assert(!bs->backing);
assert(!bs->file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
g_free(bs->opaque);
bs->opaque = NULL;
@@ -5493,9 +5499,7 @@ int bdrv_append(BlockDriverState *bs_new,
BlockDriverState *bs_top,
assert(!bs_new->backing);
bdrv_graph_rdunlock_main_loop();
- bdrv_drained_begin(bs_top);
- bdrv_drained_begin(bs_new);
-
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
child = bdrv_attach_child_noperm(bs_new, bs_top, "backing",
@@ -5517,9 +5521,7 @@ out:
bdrv_refresh_limits(bs_top, NULL, NULL);
bdrv_graph_wrunlock();
-
- bdrv_drained_end(bs_top);
- bdrv_drained_end(bs_new);
+ bdrv_drain_all_end();
return ret;
}
@@ -7626,10 +7628,6 @@ bool bdrv_child_change_aio_context(BdrvChild *c,
AioContext *ctx,
static void bdrv_set_aio_context_clean(void *opaque)
{
BdrvStateSetAioContext *state = (BdrvStateSetAioContext *) opaque;
- BlockDriverState *bs = (BlockDriverState *) state->bs;
-
- /* Paired with bdrv_drained_begin in bdrv_change_aio_context() */
- bdrv_drained_end(bs);
g_free(state);
}
@@ -7693,8 +7691,7 @@ static bool bdrv_change_aio_context(BlockDriverState *bs,
AioContext *ctx,
.bs = bs,
};
- /* Paired with bdrv_drained_end in bdrv_set_aio_context_clean() */
- bdrv_drained_begin(bs);
+ assert(qatomic_read(&bs->quiesce_counter) > 0);
tran_add(tran, &set_aio_context, state);
@@ -7702,14 +7699,12 @@ static bool bdrv_change_aio_context(BlockDriverState
*bs, AioContext *ctx,
}
/*
- * Change bs's and recursively all of its parents' and children's AioContext
- * to the given new context, returning an error if that isn't possible.
- *
- * If ignore_child is not NULL, that child (and its subgraph) will not
- * be touched.
+ * Use bdrv_try_change_aio_context() or bdrv_try_change_aio_context_locked().
*/
-int bdrv_try_change_aio_context(BlockDriverState *bs, AioContext *ctx,
- BdrvChild *ignore_child, Error **errp)
+static int bdrv_try_change_aio_context_common(BlockDriverState *bs,
+ AioContext *ctx,
+ BdrvChild *ignore_child,
+ Error **errp)
{
Transaction *tran;
GHashTable *visited;
@@ -7747,6 +7742,40 @@ int bdrv_try_change_aio_context(BlockDriverState *bs,
AioContext *ctx,
return 0;
}
+/*
+ * Change bs's and recursively all of its parents' and children's AioContext
+ * to the given new context, returning an error if that isn't possible.
+ *
+ * If ignore_child is not NULL, that child (and its subgraph) will not
+ * be touched.
+ */
+int bdrv_try_change_aio_context(BlockDriverState *bs, AioContext *ctx,
+ BdrvChild *ignore_child, Error **errp)
+{
+ int ret;
+ bdrv_drain_all_begin();
+ ret = bdrv_try_change_aio_context_common(bs, ctx, ignore_child, errp);
+ bdrv_drain_all_end();
+ return ret;
+}
+
+/*
+ * Change bs's and recursively all of its parents' and children's AioContext
+ * to the given new context, returning an error if that isn't possible.
+ *
+ * If ignore_child is not NULL, that child (and its subgraph) will not
+ * be touched.
+ *
+ * Called with the graph lock held.
+ *
+ * Called while all bs are drained.
+ */
+int bdrv_try_change_aio_context_locked(BlockDriverState *bs, AioContext *ctx,
+ BdrvChild *ignore_child, Error **errp)
+{
+ return bdrv_try_change_aio_context_common(bs, ctx, ignore_child, errp);
+}
+
void bdrv_add_aio_context_notifier(BlockDriverState *bs,
void (*attached_aio_context)(AioContext *new_context, void *opaque),
void (*detach_aio_context)(void *opaque), void *opaque)
diff --git a/block/backup.c b/block/backup.c
index 79652bf57b..9d55e55b79 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -497,10 +497,12 @@ BlockJob *backup_job_create(const char *job_id,
BlockDriverState *bs,
block_copy_set_speed(bcs, speed);
/* Required permissions are taken by copy-before-write filter target */
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
&error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
return &job->common;
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index b0f78c4bc7..70ac76f401 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -281,9 +281,11 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict
*options, int flags,
ret = 0;
fail_log:
if (ret < 0) {
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, s->log_file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
s->log_file = NULL;
qemu_mutex_destroy(&s->mutex);
}
@@ -296,10 +298,12 @@ static void blk_log_writes_close(BlockDriverState *bs)
{
BDRVBlkLogWritesState *s = bs->opaque;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, s->log_file);
s->log_file = NULL;
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
qemu_mutex_destroy(&s->mutex);
}
diff --git a/block/blkverify.c b/block/blkverify.c
index db79a36681..3a71f7498c 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -151,10 +151,12 @@ static void blkverify_close(BlockDriverState *bs)
{
BDRVBlkverifyState *s = bs->opaque;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, s->test_file);
s->test_file = NULL;
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
}
static int64_t coroutine_fn GRAPH_RDLOCK
diff --git a/block/block-backend.c b/block/block-backend.c
index a402db13f2..2b30a34662 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -889,9 +889,11 @@ void blk_remove_bs(BlockBackend *blk)
root = blk->root;
blk->root = NULL;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_root_unref_child(root);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
}
/*
@@ -904,6 +906,7 @@ int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs,
Error **errp)
GLOBAL_STATE_CODE();
bdrv_ref(bs);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
if ((bs->open_flags & BDRV_O_INACTIVE) && blk_can_inactivate(blk)) {
@@ -919,6 +922,7 @@ int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs,
Error **errp)
BDRV_CHILD_FILTERED |
BDRV_CHILD_PRIMARY,
perm, shared_perm, blk, errp);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
if (blk->root == NULL) {
return -EPERM;
}
diff --git a/block/commit.c b/block/commit.c
index 5df3d05346..6c06b894ff 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -342,6 +342,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
* this is the responsibility of the interface (i.e. whoever calls
* commit_start()).
*/
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
s->base_overlay = bdrv_find_overlay(top, base);
assert(s->base_overlay);
@@ -374,18 +375,21 @@ void commit_start(const char *job_id, BlockDriverState
*bs,
iter_shared_perms, errp);
if (ret < 0) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
}
if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
s->chain_frozen = true;
ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
if (ret < 0) {
goto fail;
diff --git a/block/mirror.c b/block/mirror.c
index a53582f17b..5c1acd650b 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1904,6 +1904,7 @@ static BlockJob *mirror_start_job(
*/
bdrv_disable_dirty_bitmap(s->dirty_bitmap);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
ret = block_job_add_bdrv(&s->common, "source", bs, 0,
BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE |
@@ -1911,6 +1912,7 @@ static BlockJob *mirror_start_job(
errp);
if (ret < 0) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
@@ -1956,16 +1958,19 @@ static BlockJob *mirror_start_job(
iter_shared_perms, errp);
if (ret < 0) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
}
if (bdrv_freeze_backing_chain(mirror_top_bs, target, errp) < 0) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
QTAILQ_INIT(&s->ops_in_flight);
diff --git a/block/qcow2.c b/block/qcow2.c
index 7774e7f090..bba7c90713 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2821,9 +2821,11 @@ qcow2_do_close(BlockDriverState *bs, bool
close_data_file)
if (close_data_file && has_data_file(bs)) {
GLOBAL_STATE_CODE();
bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, s->data_file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
s->data_file = NULL;
bdrv_graph_rdlock_main_loop();
}
diff --git a/block/quorum.c b/block/quorum.c
index 30747a6df9..3a5928d574 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1037,6 +1037,7 @@ static int quorum_open(BlockDriverState *bs, QDict
*options, int flags,
close_exit:
/* cleanup on error */
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
for (i = 0; i < s->num_children; i++) {
if (!opened[i]) {
@@ -1045,6 +1046,7 @@ close_exit:
bdrv_unref_child(bs, s->children[i]);
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
g_free(s->children);
g_free(opened);
exit:
@@ -1057,11 +1059,13 @@ static void quorum_close(BlockDriverState *bs)
BDRVQuorumState *s = bs->opaque;
int i;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
for (i = 0; i < s->num_children; i++) {
bdrv_unref_child(bs, s->children[i]);
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
g_free(s->children);
}
diff --git a/block/replication.c b/block/replication.c
index d6625c51fe..ec54a9a907 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -540,6 +540,7 @@ static void replication_start(ReplicationState *rs,
ReplicationMode mode,
return;
}
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_ref(hidden_disk->bs);
@@ -549,6 +550,7 @@ static void replication_start(ReplicationState *rs,
ReplicationMode mode,
if (local_err) {
error_propagate(errp, local_err);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
return;
}
@@ -559,6 +561,7 @@ static void replication_start(ReplicationState *rs,
ReplicationMode mode,
if (local_err) {
error_propagate(errp, local_err);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
return;
}
@@ -571,12 +574,14 @@ static void replication_start(ReplicationState *rs,
ReplicationMode mode,
!check_top_bs(top_bs, bs)) {
error_setg(errp, "No top_bs or it is invalid");
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
reopen_backing_file(bs, false, NULL);
return;
}
bdrv_op_block_all(top_bs, s->blocker);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
s->backup_job = backup_job_create(
NULL, s->secondary_disk->bs,
s->hidden_disk->bs,
@@ -649,12 +654,14 @@ static void replication_done(void *opaque, int ret)
if (ret == 0) {
s->stage = BLOCK_REPLICATION_DONE;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, s->secondary_disk);
s->secondary_disk = NULL;
bdrv_unref_child(bs, s->hidden_disk);
s->hidden_disk = NULL;
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
s->error = 0;
} else {
diff --git a/block/snapshot.c b/block/snapshot.c
index 7788e1130b..88c3190eff 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -291,9 +291,11 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
}
/* .bdrv_open() will re-attach it */
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, fallback);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
ret = bdrv_snapshot_goto(fallback_bs, snapshot_id, errp);
memset(bs->opaque, 0, drv->instance_size);
diff --git a/block/stream.c b/block/stream.c
index 999d9e56d4..6e68b0c9f8 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -80,10 +80,9 @@ static int stream_prepare(Job *job)
* may end up working with the wrong base node (or it might even have gone
* away by the time we want to use it).
*/
- bdrv_drained_begin(unfiltered_bs);
+ bdrv_drain_all_begin();
if (unfiltered_bs_cow) {
bdrv_ref(unfiltered_bs_cow);
- bdrv_drained_begin(unfiltered_bs_cow);
}
bdrv_graph_rdlock_main_loop();
@@ -124,10 +123,9 @@ static int stream_prepare(Job *job)
out:
if (unfiltered_bs_cow) {
- bdrv_drained_end(unfiltered_bs_cow);
bdrv_unref(unfiltered_bs_cow);
}
- bdrv_drained_end(unfiltered_bs);
+ bdrv_drain_all_end();
return ret;
}
@@ -373,10 +371,12 @@ void stream_start(const char *job_id, BlockDriverState
*bs,
* already have our own plans. Also don't allow resize as the image size is
* queried only at the job start and then cached.
*/
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
if (block_job_add_bdrv(&s->common, "active node", bs, 0,
basic_flags | BLK_PERM_WRITE, errp)) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
@@ -397,10 +397,12 @@ void stream_start(const char *job_id, BlockDriverState
*bs,
basic_flags, errp);
if (ret < 0) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
goto fail;
}
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
s->base_overlay = base_overlay;
s->above_base = above_base;
diff --git a/block/vmdk.c b/block/vmdk.c
index 2adec49912..e76464685e 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -271,6 +271,7 @@ static void vmdk_free_extents(BlockDriverState *bs)
BDRVVmdkState *s = bs->opaque;
VmdkExtent *e;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
for (i = 0; i < s->num_extents; i++) {
e = &s->extents[i];
@@ -283,6 +284,7 @@ static void vmdk_free_extents(BlockDriverState *bs)
}
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
g_free(s->extents);
}
@@ -1247,9 +1249,11 @@ vmdk_parse_extents(const char *desc, BlockDriverState
*bs, QDict *options,
0, 0, 0, 0, 0, &extent, errp);
if (ret < 0) {
bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, extent_file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_graph_rdlock_main_loop();
goto out;
}
@@ -1266,9 +1270,11 @@ vmdk_parse_extents(const char *desc, BlockDriverState
*bs, QDict *options,
g_free(buf);
if (ret) {
bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, extent_file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_graph_rdlock_main_loop();
goto out;
}
@@ -1277,9 +1283,11 @@ vmdk_parse_extents(const char *desc, BlockDriverState
*bs, QDict *options,
ret = vmdk_open_se_sparse(bs, extent_file, bs->open_flags, errp);
if (ret) {
bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, extent_file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_graph_rdlock_main_loop();
goto out;
}
@@ -1287,9 +1295,11 @@ vmdk_parse_extents(const char *desc, BlockDriverState
*bs, QDict *options,
} else {
error_setg(errp, "Unsupported extent type '%s'", type);
bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(bs, extent_file);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_graph_rdlock_main_loop();
ret = -ENOTSUP;
goto out;
diff --git a/blockdev.c b/blockdev.c
index 4a672f9bac..b6a4bc2bfc 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3539,6 +3539,7 @@ void qmp_x_blockdev_change(const char *parent, const char
*child,
BlockDriverState *parent_bs, *new_bs = NULL;
BdrvChild *p_child;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
parent_bs = bdrv_lookup_bs(parent, parent, errp);
@@ -3576,6 +3577,7 @@ void qmp_x_blockdev_change(const char *parent, const char
*child,
out:
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
}
BlockJobInfoList *qmp_query_block_jobs(Error **errp)
@@ -3609,12 +3611,13 @@ void qmp_x_blockdev_set_iothread(const char *node_name,
StrOrNull *iothread,
AioContext *new_context;
BlockDriverState *bs;
- GRAPH_RDLOCK_GUARD_MAINLOOP();
+ bdrv_drain_all_begin();
+ bdrv_graph_rdlock_main_loop();
bs = bdrv_find_node(node_name);
if (!bs) {
error_setg(errp, "Failed to find node with node-name='%s'", node_name);
- return;
+ goto out;
}
/* Protects against accidents. */
@@ -3622,14 +3625,14 @@ void qmp_x_blockdev_set_iothread(const char *node_name,
StrOrNull *iothread,
error_setg(errp, "Node %s is associated with a BlockBackend and could "
"be in use (use force=true to override this check)",
node_name);
- return;
+ goto out;
}
if (iothread->type == QTYPE_QSTRING) {
IOThread *obj = iothread_by_id(iothread->u.s);
if (!obj) {
error_setg(errp, "Cannot find iothread %s", iothread->u.s);
- return;
+ goto out;
}
new_context = iothread_get_aio_context(obj);
@@ -3637,7 +3640,11 @@ void qmp_x_blockdev_set_iothread(const char *node_name,
StrOrNull *iothread,
new_context = qemu_get_aio_context();
}
- bdrv_try_change_aio_context(bs, new_context, NULL, errp);
+ bdrv_try_change_aio_context_locked(bs, new_context, NULL, errp);
+
+out:
+ bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_end();
}
QemuOptsList qemu_common_drive_opts = {
diff --git a/blockjob.c b/blockjob.c
index 32007f31a9..390301d3cf 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -198,6 +198,7 @@ void block_job_remove_all_bdrv(BlockJob *job)
* one to make sure that such a concurrent access does not attempt
* to process an already freed BdrvChild.
*/
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
while (job->nodes) {
GSList *l = job->nodes;
@@ -211,6 +212,7 @@ void block_job_remove_all_bdrv(BlockJob *job)
g_slist_free_1(l);
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
}
bool block_job_has_bdrv(BlockJob *job, BlockDriverState *bs)
@@ -496,6 +498,7 @@ void *block_job_create(const char *job_id, const
BlockJobDriver *driver,
int ret;
GLOBAL_STATE_CODE();
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
if (job_id == NULL && !(flags & JOB_INTERNAL)) {
@@ -506,6 +509,7 @@ void *block_job_create(const char *job_id, const
BlockJobDriver *driver,
flags, cb, opaque, errp);
if (job == NULL) {
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
return NULL;
}
@@ -544,10 +548,12 @@ void *block_job_create(const char *job_id, const
BlockJobDriver *driver,
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
return job;
fail:
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
job_early_fail(&job->job);
return NULL;
}
diff --git a/include/block/block-global-state.h
b/include/block/block-global-state.h
index 9be34b3c99..da842e6019 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -277,8 +277,12 @@ bool bdrv_debug_is_suspended(BlockDriverState *bs, const
char *tag);
bool bdrv_child_change_aio_context(BdrvChild *c, AioContext *ctx,
GHashTable *visited, Transaction *tran,
Error **errp);
-int bdrv_try_change_aio_context(BlockDriverState *bs, AioContext *ctx,
- BdrvChild *ignore_child, Error **errp);
+int GRAPH_UNLOCKED
+bdrv_try_change_aio_context(BlockDriverState *bs, AioContext *ctx,
+ BdrvChild *ignore_child, Error **errp);
+int GRAPH_RDLOCK
+bdrv_try_change_aio_context_locked(BlockDriverState *bs, AioContext *ctx,
+ BdrvChild *ignore_child, Error **errp);
int GRAPH_RDLOCK bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index 290cd2a70e..d931c5183e 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -772,9 +772,11 @@ static void test_blockjob_common_drain_node(enum
drain_type drain_type,
tjob->bs = src;
job = &tjob->common;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
switch (result) {
case TEST_JOB_SUCCESS:
@@ -953,11 +955,13 @@ static void bdrv_test_top_close(BlockDriverState *bs)
{
BdrvChild *c, *next_c;
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
bdrv_unref_child(bs, c);
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
}
static int coroutine_fn GRAPH_RDLOCK
@@ -1047,10 +1051,12 @@ static void do_test_delete_by_drain(bool
detach_instead_of_delete,
null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR |
BDRV_O_PROTOCOL,
&error_abort);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds,
BDRV_CHILD_DATA, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
/* This child will be the one to pass to requests through to, and
* it will stall until a drain occurs */
@@ -1058,21 +1064,25 @@ static void do_test_delete_by_drain(bool
detach_instead_of_delete,
&error_abort);
child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
/* Takes our reference to child_bs */
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child",
&child_of_bds,
BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY,
&error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
/* This child is just there to be deleted
* (for detach_instead_of_delete == true) */
null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR |
BDRV_O_PROTOCOL,
&error_abort);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds,
BDRV_CHILD_DATA,
&error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
blk_insert_bs(blk, bs, &error_abort);
@@ -1155,6 +1165,7 @@ static void no_coroutine_fn detach_indirect_bh(void
*opaque)
bdrv_dec_in_flight(data->child_b->bs);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_unref_child(data->parent_b, data->child_b);
@@ -1163,6 +1174,7 @@ static void no_coroutine_fn detach_indirect_bh(void
*opaque)
&child_of_bds, BDRV_CHILD_DATA,
&error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
}
static void coroutine_mixed_fn detach_by_parent_aio_cb(void *opaque, int ret)
@@ -1260,6 +1272,7 @@ static void TSA_NO_TSA test_detach_indirect(bool
by_parent_cb)
/* Set child relationships */
bdrv_ref(b);
bdrv_ref(a);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_of_bds,
BDRV_CHILD_DATA, &error_abort);
@@ -1271,6 +1284,7 @@ static void TSA_NO_TSA test_detach_indirect(bool
by_parent_cb)
by_parent_cb ? &child_of_bds :
&detach_by_driver_cb_class,
BDRV_CHILD_DATA, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
g_assert_cmpint(parent_a->refcnt, ==, 1);
g_assert_cmpint(parent_b->refcnt, ==, 1);
@@ -1687,6 +1701,7 @@ static void test_drop_intermediate_poll(void)
* Establish the chain last, so the chain links are the first
* elements in the BDS.parents lists
*/
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
for (i = 0; i < 3; i++) {
if (i) {
@@ -1696,6 +1711,7 @@ static void test_drop_intermediate_poll(void)
}
}
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
job = block_job_create("job", &test_simple_job_driver, NULL, job_node,
0, BLK_PERM_ALL, 0, 0, NULL, NULL, &error_abort);
@@ -1942,10 +1958,12 @@ static void do_test_replace_child_mid_drain(int
old_drain_count,
new_child_bs->total_sectors = 1;
bdrv_ref(old_child_bs);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(parent_bs, old_child_bs, "child", &child_of_bds,
BDRV_CHILD_COW, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
parent_s->setup_completed = true;
for (i = 0; i < old_drain_count; i++) {
diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c
index d743abb4bb..7b03ebe4b0 100644
--- a/tests/unit/test-bdrv-graph-mod.c
+++ b/tests/unit/test-bdrv-graph-mod.c
@@ -137,10 +137,12 @@ static void test_update_perm_tree(void)
blk_insert_bs(root, bs, &error_abort);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(filter, bs, "child", &child_of_bds,
BDRV_CHILD_DATA, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
ret = bdrv_append(filter, bs, NULL);
g_assert_cmpint(ret, <, 0);
@@ -204,11 +206,13 @@ static void test_should_update_child(void)
bdrv_set_backing_hd(target, bs, &error_abort);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
g_assert(target->backing->bs == bs);
bdrv_attach_child(filter, target, "target", &child_of_bds,
BDRV_CHILD_DATA, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_append(filter, bs, &error_abort);
bdrv_graph_rdlock_main_loop();
@@ -244,6 +248,7 @@ static void test_parallel_exclusive_write(void)
bdrv_ref(base);
bdrv_ref(fl1);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(top, fl1, "backing", &child_of_bds,
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
@@ -257,6 +262,7 @@ static void test_parallel_exclusive_write(void)
bdrv_replace_node(fl1, fl2, &error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_drained_end(fl2);
bdrv_drained_end(fl1);
@@ -363,6 +369,7 @@ static void test_parallel_perm_update(void)
*/
bdrv_ref(base);
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(top, ws, "file", &child_of_bds, BDRV_CHILD_DATA,
&error_abort);
@@ -377,6 +384,7 @@ static void test_parallel_perm_update(void)
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
&error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
/* Select fl1 as first child to be active */
s->selected = c_fl1;
@@ -430,11 +438,13 @@ static void test_append_greedy_filter(void)
BlockDriverState *base = no_perm_node("base");
BlockDriverState *fl = exclusive_writer_node("fl1");
+ bdrv_drain_all_begin();
bdrv_graph_wrlock();
bdrv_attach_child(top, base, "backing", &child_of_bds,
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
&error_abort);
bdrv_graph_wrunlock();
+ bdrv_drain_all_end();
bdrv_append(fl, base, &error_abort);
bdrv_unref(fl);
--
2.39.5
- [PATCH 01/11] block: remove outdated comments about AioContext locking, (continued)
- [PATCH 01/11] block: remove outdated comments about AioContext locking, Fiona Ebner, 2025/05/08
- [PATCH 05/11] block: move drain outside of read-locked bdrv_inactivate_recurse(), Fiona Ebner, 2025/05/08
- [PATCH 11/11] iotests/graph-changes-while-io: add test case with removal of lower snapshot, Fiona Ebner, 2025/05/08
- [PATCH 06/11] blockdev: drain while unlocked in internal_snapshot_action(), Fiona Ebner, 2025/05/08
- [PATCH 08/11] block: mark bdrv_drained_begin() as GRAPH_UNLOCKED, Fiona Ebner, 2025/05/08
- [PATCH 09/11] block: move drain out of bdrv_change_aio_context(),
Fiona Ebner <=
- [PATCH 03/11] block/snapshot: move drain outside of read-locked bdrv_snapshot_delete(), Fiona Ebner, 2025/05/08
- [PATCH 07/11] blockdev: drain while unlocked in external_snapshot_action(), Fiona Ebner, 2025/05/08
- [PATCH 10/11] block/graph-lock: add drain flag to bdrv_graph_wr{, un}lock, Fiona Ebner, 2025/05/08