diff options
author | Fam Zheng <famz@redhat.com> | 2017-04-10 20:20:17 +0800 |
---|---|---|
committer | Fam Zheng <famz@redhat.com> | 2017-04-11 20:07:15 +0800 |
commit | e92f0e1910f0655a0edd8d87c5a7262d36517a89 (patch) | |
tree | 6a50c54236c0c103ed5b82c2fc362860630822ae /tests/qemu-iotests | |
parent | 324ec3e4f26e0a2a422478db4b9992f8aad3bde4 (diff) |
block: Use bdrv_coroutine_enter to start I/O coroutines
BDRV_POLL_WHILE waits for the started I/O by releasing bs's ctx then polling
the main context, which relies on the yielded coroutine continuing on bs->ctx
before notifying qemu_aio_context with bdrv_wakeup().
Thus, using qemu_coroutine_enter to start I/O is wrong because if the coroutine
is entered from main loop, co->ctx will be qemu_aio_context, as a result of the
"release, poll, acquire" loop of BDRV_POLL_WHILE, race conditions happen when
both main thread and the iothread access the same BDS:
main loop iothread
-----------------------------------------------------------------------
blockdev_snapshot
aio_context_acquire(bs->ctx)
virtio_scsi_data_plane_handle_cmd
bdrv_drained_begin(bs->ctx)
bdrv_flush(bs)
bdrv_co_flush(bs) aio_context_acquire(bs->ctx).enter
...
qemu_coroutine_yield(co)
BDRV_POLL_WHILE()
aio_context_release(bs->ctx)
aio_context_acquire(bs->ctx).return
...
aio_co_wake(co)
aio_poll(qemu_aio_context) ...
co_schedule_bh_cb() ...
qemu_coroutine_enter(co) ...
/* (A) bdrv_co_flush(bs) /* (B) I/O on bs */
continues... */
aio_context_release(bs->ctx)
aio_context_acquire(bs->ctx)
Note that in above case, bdrv_drained_begin() doesn't do the "release,
poll, acquire" in BDRV_POLL_WHILE, because bs->in_flight == 0.
Fix this by using bdrv_coroutine_enter and enter coroutine in the right
context.
iotests 109 output is updated because the coroutine reenter flow during
mirror job complete is different (now through co_queue_wakeup, instead
of the unconditional qemu_coroutine_switch before), making the end job
len different.
Signed-off-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'tests/qemu-iotests')
-rw-r--r-- | tests/qemu-iotests/109.out | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/tests/qemu-iotests/109.out b/tests/qemu-iotests/109.out index e5d70d75f1..55fe536d56 100644 --- a/tests/qemu-iotests/109.out +++ b/tests/qemu-iotests/109.out @@ -10,7 +10,7 @@ Automatically detecting the format is dangerous for raw images, write operations Specify the 'raw' format explicitly to remove the restrictions. {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}} -{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} {"return": []} read 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) @@ -73,7 +73,7 @@ Automatically detecting the format is dangerous for raw images, write operations Specify the 'raw' format explicitly to remove the restrictions. {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}} -{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} {"return": []} read 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) @@ -115,7 +115,7 @@ Automatically detecting the format is dangerous for raw images, write operations Specify the 'raw' format explicitly to remove the restrictions. {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}} -{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} {"return": []} read 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) @@ -135,7 +135,7 @@ Automatically detecting the format is dangerous for raw images, write operations Specify the 'raw' format explicitly to remove the restrictions. {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}} -{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": OFFSET, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": OFFSET, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} {"return": []} read 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) @@ -195,7 +195,7 @@ Automatically detecting the format is dangerous for raw images, write operations Specify the 'raw' format explicitly to remove the restrictions. {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}} -{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2048, "offset": OFFSET, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": OFFSET, "speed": 0, "type": "mirror", "error": "Operation not permitted"}} {"return": []} read 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) |