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 <be...@igalia.com>
---
tests/qemu-iotests/030 | 17 +++++++++++++++++
tests/qemu-iotests/030.out | 4 ++--
2 files changed, 19 insertions(+), 2 deletions(-)
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
--
2.11.0
