aio_context should be locked in the similar way as was done in QMP
snapshot creation in the other case there are a lot of possible
troubles if native AIO mode is enabled for disk.
- the command can hang (HMP thread) with missed wakeup (the operation is
actually complete)
io_submit
ioq_submit
laio_submit
raw_aio_submit
raw_aio_readv
bdrv_co_io_em
bdrv_co_readv_em
bdrv_aligned_preadv
bdrv_co_do_preadv
bdrv_co_do_readv
bdrv_co_readv
qcow2_co_readv
bdrv_aligned_preadv
bdrv_co_do_pwritev
bdrv_rw_co_entry
- QEMU can assert in coroutine re-enter
__GI_abort
qemu_coroutine_enter
bdrv_co_io_em_complete
qemu_laio_process_completion
qemu_laio_completion_bh
aio_bh_poll
aio_dispatch
aio_poll
iothread_run
qemu_fopen_bdrv and bdrv_fclose are used in real snapshot operations only
along with block drivers. This change should influence only HMP snapshot
operations.
AioContext lock is reqursive. Thus nested locking should not be a problem.
Signed-off-by: Denis V. Lunev <[email protected]>
CC: Stefan Hajnoczi <[email protected]>
CC: Paolo Bonzini <[email protected]>
CC: Juan Quintela <[email protected]>
CC: Amit Shah <[email protected]>
---
block/snapshot.c | 5 +++++
migration/savevm.c | 18 +++++++++++++++---
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/block/snapshot.c b/block/snapshot.c
index 89500f2..f6fa17a 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -259,6 +259,9 @@ void bdrv_snapshot_delete_by_id_or_name(BlockDriverState
*bs,
{
int ret;
Error *local_err = NULL;
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(aio_context);
ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
if (ret == -ENOENT || ret == -EINVAL) {
@@ -267,6 +270,8 @@ void bdrv_snapshot_delete_by_id_or_name(BlockDriverState
*bs,
ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
}
+ aio_context_release(aio_context);
+
if (ret < 0) {
error_propagate(errp, local_err);
}
diff --git a/migration/savevm.c b/migration/savevm.c
index dbcc39a..1653f56 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -153,7 +153,11 @@ static ssize_t block_get_buffer(void *opaque, uint8_t
*buf, int64_t pos,
static int bdrv_fclose(void *opaque)
{
- return bdrv_flush(opaque);
+ BlockDriverState *bs = (BlockDriverState *)opaque;
+ int ret = bdrv_flush(bs);
+
+ aio_context_release(bdrv_get_aio_context(bs));
+ return ret;
}
static const QEMUFileOps bdrv_read_ops = {
@@ -169,10 +173,18 @@ static const QEMUFileOps bdrv_write_ops = {
static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable)
{
+ QEMUFile *file;
+
if (is_writable) {
- return qemu_fopen_ops(bs, &bdrv_write_ops);
+ file = qemu_fopen_ops(bs, &bdrv_write_ops);
+ } else {
+ file = qemu_fopen_ops(bs, &bdrv_read_ops);
+ }
+
+ if (file != NULL) {
+ aio_context_acquire(bdrv_get_aio_context(bs));
}
- return qemu_fopen_ops(bs, &bdrv_read_ops);
+ return file;
}
--
2.1.4
