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[PATCH 15/20] block-gen: assert that {bdrv/blk}_co_flush is always calle
From: |
Emanuele Giuseppe Esposito |
Subject: |
[PATCH 15/20] block-gen: assert that {bdrv/blk}_co_flush is always called with graph rdlock taken |
Date: |
Wed, 16 Nov 2022 08:48:45 -0500 |
This function, in addition to be called by a generated_co_wrapper,
is also called by the blk_* API.
The strategy is to always take the lock at the function called
when the coroutine is created, to avoid recursive locking.
Protecting bdrv_co_flush() implies that the following BlockDriver
callbacks always called with graph rdlock taken:
- bdrv_co_flush
- bdrv_co_flush_to_os
- bdrv_co_flush_to_disk
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
block/block-backend.c | 3 ++-
block/io.c | 1 +
include/block/block_int-common.h | 6 ++++++
3 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/block/block-backend.c b/block/block-backend.c
index 083ed6009e..d660772375 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1759,8 +1759,9 @@ int coroutine_fn blk_co_pdiscard(BlockBackend *blk,
int64_t offset,
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static int coroutine_fn blk_co_do_flush(BlockBackend *blk)
{
- blk_wait_while_drained(blk);
IO_CODE();
+ blk_wait_while_drained(blk);
+ GRAPH_RDLOCK_GUARD();
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
diff --git a/block/io.c b/block/io.c
index cfc201ef91..0bf3919939 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2757,6 +2757,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
int ret = 0;
IO_CODE();
+ assert_bdrv_graph_readable();
bdrv_inc_in_flight(bs);
if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 64c5bb64de..bab0521943 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -661,6 +661,8 @@ struct BlockDriver {
* Flushes all data for all layers by calling bdrv_co_flush for underlying
* layers, if needed. This function is needed for deterministic
* synchronization of the flush finishing callback.
+ *
+ * Called with graph rdlock taken.
*/
int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs);
@@ -671,6 +673,8 @@ struct BlockDriver {
/*
* Flushes all data that was already written to the OS all the way down to
* the disk (for example file-posix.c calls fsync()).
+ *
+ * Called with graph rdlock taken.
*/
int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
@@ -678,6 +682,8 @@ struct BlockDriver {
* Flushes all internal caches to the OS. The data may still sit in a
* writeback cache of the host OS, but it will survive a crash of the qemu
* process.
+ *
+ * Called with graph rdlock held.
*/
int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
--
2.31.1
- [PATCH 08/20] block-coroutine-wrapper.py: take the graph rdlock in bdrv_* functions, (continued)
- [PATCH 08/20] block-coroutine-wrapper.py: take the graph rdlock in bdrv_* functions, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 16/20] block-gen: assert that bdrv_co_{read/write}v_vmstate are always called with graph rdlock taken, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 04/20] block.c: wrlock in bdrv_replace_child_noperm, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 20/20] block-gen: assert that nbd_co_do_establish_connection is always called with graph rdlock taken, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 09/20] block-backend: introduce new generated_co_wrapper_blk annotation, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 07/20] graph-lock: implement WITH_GRAPH_RDLOCK_GUARD and GRAPH_RDLOCK_GUARD macros, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 10/20] block-gen: assert that {bdrv/blk}_co_truncate is always called with graph rdlock taken, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 03/20] async: register/unregister aiocontext in graph lock list, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 05/20] block: remove unnecessary assert_bdrv_graph_writable(), Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 14/20] block-gen: assert that bdrv_co_pread is always called with graph rdlock taken, Emanuele Giuseppe Esposito, 2022/11/16
- [PATCH 15/20] block-gen: assert that {bdrv/blk}_co_flush is always called with graph rdlock taken,
Emanuele Giuseppe Esposito <=
- [PATCH 17/20] block-gen: assert that bdrv_co_pdiscard is always called with graph rdlock taken, Emanuele Giuseppe Esposito, 2022/11/16
- Re: [PATCH 00/20] Protect the block layer with a rwlock: part 1, Emanuele Giuseppe Esposito, 2022/11/21