This is part of resolving the deadlock mentioned in commit "block:
move draining out of bdrv_change_aio_context() and mark GRAPH_RDLOCK".
bdrv_root_unref_child() is called by:
1. blk_remove_bs(), where a drained section is introduced.
2. bdrv_unref_child(), which runs under the graph lock, so the drain
will be moved further up to its callers.
3. block_job_remove_all_bdrv(), where a drained section is introduced.
For all callers of bdrv_unref_child() a drained section is introduced,
they are not explicilty listed here. The caller quorum_del_child()
holds the graph lock, so it is not actually allowed to drain. This
will be addressed in the next commit.
Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---
Changes in v2:
* Split up into smaller pieces, flesh out commit messages.
block.c | 6 ++++--
block/blklogwrites.c | 4 ++++
block/blkverify.c | 2 ++
block/block-backend.c | 2 ++
block/qcow2.c | 2 ++
block/quorum.c | 6 ++++++
block/replication.c | 2 ++
block/snapshot.c | 2 ++
block/vmdk.c | 10 ++++++++++
blockjob.c | 2 ++
tests/unit/test-bdrv-drain.c | 2 ++
11 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index b9de3a25cf..dfe665e457 100644
--- a/block.c
+++ b/block.c
@@ -1721,12 +1721,14 @@ 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;
@@ -3316,10 +3318,8 @@ 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_drain_all_begin();
bdrv_try_change_aio_context_locked(child_bs, qemu_get_aio_context(),
NULL, NULL);
- bdrv_drain_all_end();
}
bdrv_schedule_unref(child_bs);
@@ -5163,6 +5163,7 @@ 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);
@@ -5171,6 +5172,7 @@ 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;
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 24cae3cb55..68209bb2f7 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();
}
/*
diff --git a/block/qcow2.c b/block/qcow2.c
index 66fba89b41..420918b3c3 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 ed8ce801ee..81407a38ee 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);
}
@@ -1143,7 +1147,9 @@ quorum_del_child(BlockDriverState *bs, BdrvChild *child,
Error **errp)
(s->num_children - i - 1) * sizeof(BdrvChild *));
s->children = g_renew(BdrvChild *, s->children, --s->num_children);
+ bdrv_drain_all_begin();
bdrv_unref_child(bs, child);
+ bdrv_drain_all_end();
quorum_refresh_flags(bs);
}
diff --git a/block/replication.c b/block/replication.c
index 54cbd03e00..0879718854 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -656,12 +656,14 @@ 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 9f300a78bd..28c9c43621 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/vmdk.c b/block/vmdk.c
index 9c7ab037e1..89a7250120 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/blockjob.c b/blockjob.c
index 44991e3ff7..e68181a35b 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)
diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index ac76525e5a..c33f7d31c2 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -955,11 +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
--
2.39.5
