[Qemu-devel] [PATCH for 2.5 v8 0/10] dataplane snapshot fixes

["Denis V. Lunev" <den@openvz.org>]

with test
    while /bin/true ; do
        virsh snapshot-create rhel7
        sleep 10
        virsh snapshot-delete rhel7 --current
    done
with enabled iothreads on a running VM leads to a lot of troubles: hangs,
asserts, errors.

Anyway, I think that the construction like
    assert(aio_context_is_locked(aio_context));
should be widely used to ensure proper locking.

Changes from v7:
- patch 5: fixes for bdrv_all_find_snapshot. Changed parameter name to
  skip_read_only which better reflects the meaning of the value and
  fixed checks inside to conform the note from Stefan

Changes from v6:
- tricky part dropped from patch 7
- patch 5 reworked to process snapshot list differently in info commands
  and on savevm

Changes from v5:
- dropped already merged patch 11
- fixed spelling in patch 1
- changed order of condition in loops in all patches. Thank you Stefan
- dropped patch 9
- aio_context is not acquired any more in bdrv_all_find_vmstate_bs by request
  of Stefan
- patch 10 is implemented in completely different way

Changes from v4:
- only migration/savevm.c code and monitor is affected now. Generic block
  layer stuff will be sent separately to speedup merging. The approach
  in general was negotiated with Juan and Stefan.

Changes from v3:
- more places found
- new aio_poll concept, see patch 10

Changes from v2:
- droppped patch 5 as already merged
- changed locking scheme in patch 4 by suggestion of Juan

Changes from v1:
- aio-context locking added
- comment is rewritten

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>

Denis V. Lunev (10):
  snapshot: create helper to test that block drivers supports snapshots
  snapshot: return error code from bdrv_snapshot_delete_by_id_or_name
  snapshot: create bdrv_all_delete_snapshot helper
  snapshot: create bdrv_all_goto_snapshot helper
  snapshot: create bdrv_all_find_snapshot helper
  migration: drop find_vmstate_bs check in hmp_delvm
  snapshot: create bdrv_all_create_snapshot helper
  migration: reorder processing in hmp_savevm
  migration: implement bdrv_all_find_vmstate_bs helper
  migration: normalize locking in migration/savevm.c

 block/snapshot.c         | 135 ++++++++++++++++++++++++++++++-
 include/block/snapshot.h |  25 +++++-
 migration/savevm.c       | 207 +++++++++++++++--------------------------------
 3 files changed, 217 insertions(+), 150 deletions(-)
-- 
2.5.0