[Qemu-devel] [PATCH 0/2] block: Fix attaching drained child node

[Kevin Wolf <kwolf@redhat.com>]

This fixes the following case that was reported by Max and was caused by
not correctly waiting for activity to cease on the parent node before
attaching a drained child node:

$ ./qemu-img create -f qed foo.qed 64M
Formatting 'foo.qed', fmt=qed size=67108864 cluster_size=65536
$ echo "{'execute':'qmp_capabilities'}
        {'execute':'blockdev-snapshot',
         'arguments':{'node':'backing','overlay':'overlay'}}
        {'execute':'quit'}" | \
    x86_64-softmmu/qemu-system-x86_64 -qmp stdio -nodefaults \
        -blockdev "{'node-name':'backing','driver':'null-co'}" \
        -blockdev "{'node-name':'overlay','driver':'qed',
                    'file':{'driver':'file','filename':'foo.qed'}}"
{"QMP": {"version": {"qemu": {"micro": 50, "minor": 12, "major": 2},
"package": "v2.12.0-1422-g0109e7e6f8"}, "capabilities": []}}
{"return": {}}
qemu-system-x86_64: block.c:3434: bdrv_replace_node: Assertion
`!atomic_read(&to->in_flight)' failed.
[1]    5252 done                 echo  |
       5253 abort (core dumped)  x86_64-softmmu/qemu-system-x86_64 -qmp
stdio -nodefaults -blockdev  -blockdev

Kevin Wolf (2):
  block: Poll after drain on attaching a node
  test-bdrv-drain: Test bdrv_append() to drained node

 include/block/block.h     |  8 ++++++++
 include/block/block_int.h |  3 +++
 block.c                   |  2 +-
 block/io.c                | 26 ++++++++++++++++++++------
 tests/test-bdrv-drain.c   | 43 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 75 insertions(+), 7 deletions(-)

-- 
2.13.6