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[Qemu-block] [PATCH for 2.12 1/1] block: allow recursive calling of bdrv
From: |
Denis V. Lunev |
Subject: |
[Qemu-block] [PATCH for 2.12 1/1] block: allow recursive calling of bdrv_set_aio_context |
Date: |
Tue, 27 Mar 2018 16:30:18 +0300 |
We have received the following assert on QEMU 2.9:
(gdb) bt
0 0x00007f6f67d281f7 in __GI_raise ()
1 0x00007f6f67d298e8 in __GI_abort ()
2 0x00007f6f67d21266 in __assert_fail_base ()
3 0x00007f6f67d21312 in __GI___assert_fail ()
4 0x000055a8faf76f9f in bdrv_detach_aio_context ()
5 0x000055a8faf76f68 in bdrv_detach_aio_context ()
6 0x000055a8faf770c6 in bdrv_set_aio_context ()
7 0x000055a8fafb780d in blk_set_aio_context ()
8 0x000055a8faf7af08 in block_job_attached_aio_context ()
9 0x000055a8faf77043 in bdrv_attach_aio_context ()
10 0x000055a8faf770d9 in bdrv_set_aio_context ()
11 0x000055a8fafb780d in blk_set_aio_context ()
12 0x000055a8fad580e7 in virtio_blk_data_plane_stop ()
13 0x000055a8faf11da5 in virtio_bus_stop_ioeventfd ()
14 0x000055a8fad85604 in virtio_vmstate_change ()
15 0x000055a8fae1ba52 in vm_state_notify ()
16 0x000055a8fad273e5 in do_vm_stop ()
17 vm_stop ()
18 0x000055a8face8f28 in main_loop_should_exit ()
19 main_loop ()
20 main ()
(gdb)
It does not look, that the code is fundumentally different in 2.12.
block_job_attached_aio_context() calls backup_attached_aio_context(),
which in turn calls bdrv_detach_aio_context() again. This results in
assert(!bs->walking_aio_notifiers).
The code in mirror is basically the same. The patch replaces boolean
condition with incremental counter, which should solve the problem.
Signed-off-by: Denis V. Lunev <address@hidden>
CC: Kevin Wolf <address@hidden>
CC: Max Reitz <address@hidden>
---
include/block/block_int.h | 2 +-
block.c | 12 ++++++------
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 29cafa4..a290711 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -613,7 +613,7 @@ struct BlockDriverState {
* BDS may register themselves in this list to be notified of changes
* regarding this BDS's context */
QLIST_HEAD(, BdrvAioNotifier) aio_notifiers;
- bool walking_aio_notifiers; /* to make removal during iteration safe */
+ int walking_aio_notifiers; /* to make removal during iteration safe */
char filename[PATH_MAX];
char backing_file[PATH_MAX]; /* if non zero, the image is a diff of
diff --git a/block.c b/block.c
index a8da4f2..82cc07b 100644
--- a/block.c
+++ b/block.c
@@ -4739,8 +4739,7 @@ void bdrv_detach_aio_context(BlockDriverState *bs)
return;
}
- assert(!bs->walking_aio_notifiers);
- bs->walking_aio_notifiers = true;
+ bs->walking_aio_notifiers++;
QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) {
if (baf->deleted) {
bdrv_do_remove_aio_context_notifier(baf);
@@ -4751,7 +4750,8 @@ void bdrv_detach_aio_context(BlockDriverState *bs)
/* Never mind iterating again to check for ->deleted. bdrv_close() will
* remove remaining aio notifiers if we aren't called again.
*/
- bs->walking_aio_notifiers = false;
+ bs->walking_aio_notifiers--;
+ assert(bs->walking_aio_notifiers >= 0);
if (bs->drv->bdrv_detach_aio_context) {
bs->drv->bdrv_detach_aio_context(bs);
@@ -4782,8 +4782,7 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
bs->drv->bdrv_attach_aio_context(bs, new_context);
}
- assert(!bs->walking_aio_notifiers);
- bs->walking_aio_notifiers = true;
+ bs->walking_aio_notifiers++;
QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) {
if (ban->deleted) {
bdrv_do_remove_aio_context_notifier(ban);
@@ -4791,7 +4790,8 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
ban->attached_aio_context(new_context, ban->opaque);
}
}
- bs->walking_aio_notifiers = false;
+ bs->walking_aio_notifiers--;
+ assert(bs->walking_aio_notifiers >= 0);
}
void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
--
2.7.4
- [Qemu-block] [PATCH for 2.12 1/1] block: allow recursive calling of bdrv_set_aio_context,
Denis V. Lunev <=