| Message ID | 001949bcb5ba28d72ab14731dbcf8e6b239ebe78.1553789986.git.berto@igalia.com |
|---|---|
| State | New |
| Headers | show |
| Series | freeze the backing chain earlier in stream_start() | expand |
28.03.2019 19:25, Alberto Garcia wrote: > The base node of a block-stream operation indicates the first image > from the backing chain starting from which no data is copied to the > top node. > > The block-stream job allows others to use that base image, so a second > block-stream job could be writing to it at the same time. An important > restriction is that the base image must not disappear while the stream > job is ongoing. stream_start() freezes the backing chain from top to > base with that purpose but it does it too late in the code so there is > a race condition there. > > This bug was fixed in the previous commit, and this patch contains an > iotest for this scenario. > > Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030 index 276e06b5ba..c6311d1825 100755 --- a/tests/qemu-iotests/030 +++ b/tests/qemu-iotests/030 @@ -314,6 +314,23 @@ class TestParallelOps(iotests.QMPTestCase): self.wait_until_completed(drive='commit-drive0') + # In this case the base node of the stream job is the same as the + # top node of commit job. Since block-commit removes the top node + # when it finishes, this is not allowed. + def test_overlapping_4(self): + self.assert_no_active_block_jobs() + + # Commit from node2 into node0 + result = self.vm.qmp('block-commit', device='drive0', top=self.imgs[2], base=self.imgs[0]) + self.assert_qmp(result, 'return', {}) + + # Stream from node2 into node4 + result = self.vm.qmp('block-stream', device='node4', base_node='node2', job_id='node4') + self.assert_qmp(result, 'error/class', 'GenericError') + + self.wait_until_completed() + self.assert_no_active_block_jobs() + # Test a block-stream and a block-commit job in parallel # Here the stream job is supposed to finish quickly in order to reproduce # the scenario that triggers the bug fixed in 3d5d319e1221 and 1a63a907507 diff --git a/tests/qemu-iotests/030.out b/tests/qemu-iotests/030.out index 42314e9c00..4fd1c2dcd2 100644 --- a/tests/qemu-iotests/030.out +++ b/tests/qemu-iotests/030.out @@ -1,5 +1,5 @@ -........................ +......................... ---------------------------------------------------------------------- -Ran 24 tests +Ran 25 tests OK
The base node of a block-stream operation indicates the first image from the backing chain starting from which no data is copied to the top node. The block-stream job allows others to use that base image, so a second block-stream job could be writing to it at the same time. An important restriction is that the base image must not disappear while the stream job is ongoing. stream_start() freezes the backing chain from top to base with that purpose but it does it too late in the code so there is a race condition there. This bug was fixed in the previous commit, and this patch contains an iotest for this scenario. Signed-off-by: Alberto Garcia <berto@igalia.com> --- tests/qemu-iotests/030 | 17 +++++++++++++++++ tests/qemu-iotests/030.out | 4 ++-- 2 files changed, 19 insertions(+), 2 deletions(-)