[Qemu-devel] [PATCH V4 0/6] qcow2: rollback the modification on fail in snapshot creation

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

V2:
  1: all fail case will goto fail section.
  2: add the goto code.
v3:
  Address Stefan's comments:
  2: don't goto fail after allocation failure.
  3: use sn->l1size correctly in qcow2_free_cluster().
  4-7: add test case to verify the error paths.
  Other:
  1: new patch fix a existing bug, which will be exposed in error path test.
v4:
  General change:
  rebased on upstream since error path for qcow2_write_snapshots() already
exist in upstream. removed old patch 1 since it is fixed by Max in upstream.
  5: moved the snapshot_l1_update event just before write operation, instead of
before overlap check, since it is more straight.
  6: remove a duplicated error path test about flush after snapshot list
update, add a filter which replace number to X, since now in error in report
detailed message including error cluster number.
  Address Stefan's comments:
  1, 2, 4: add *errp to store detailed error message, instead of error_report()
and compile time determined debug printf message.
  3: do not free cluster when fail in header update for safety reason.
  Address Eric's comments:
  1, 2, 4: add *errp to store detailed error message, instead of error_report()
and compile time determined debug printf message.
  5: squashed patches that add and use debug events.
  6: added comments about test only on Linux.

Wenchao Xia (6):
  1 snapshot: add parameter *errp in snapshot create
  2 qcow2: add error message in qcow2_write_snapshots()
  3 qcow2: do not free clusters when fail in header update in
        qcow2_write_snapshots
  4 qcow2: cancel the modification on fail in qcow2_snapshot_create()
  5 blkdebug: add debug events for snapshot
  6 qemu-iotests: add test for qcow2 snapshot

 block/blkdebug.c                 |    4 +
 block/qcow2-snapshot.c           |  106 +++++++++++++++++--
 block/qcow2.h                    |    4 +-
 block/rbd.c                      |   21 ++--
 block/sheepdog.c                 |   29 ++++--
 block/snapshot.c                 |   19 +++-
 blockdev.c                       |   10 +-
 include/block/block.h            |    4 +
 include/block/block_int.h        |    5 +-
 include/block/snapshot.h         |    5 +-
 qemu-img.c                       |   10 +-
 savevm.c                         |   12 ++-
 tests/qemu-iotests/068           |  214 ++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/068.out       |   35 ++++++
 tests/qemu-iotests/common.filter |    7 ++
 tests/qemu-iotests/group         |    1 +
 16 files changed, 431 insertions(+), 55 deletions(-)
 create mode 100755 tests/qemu-iotests/068
 create mode 100644 tests/qemu-iotests/068.out