[Qemu-devel] [PATCH V4 0/5] block: make qmp_transaction extendable

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

  This serial will package backing chain snapshot code as one case, to make it
possible adding more operations later.

v2:
  Address Kevin's comments:
  Use the same prototype prepare, commit, rollback model in original code,
commit should never fail.

v3:
  Address Stefan's comments:
  3/5, 4/5: remove *action parameter since later only BlkTransactionStates* is
needed.
  5/5: embbed BlkTransactionStates in ExternalSnapshotStates, *opaque is
removed, related call back function format change for external snapshot.
  Address Kevin's comments:
  removed all indention in commit message.
  1/5: return void for prepare() function, *errp plays the role as error
checker.
  5/5: mark *commit callback must exist, *rollback callback can be NULL. Align
"callback =" in "const BdrvActionOps external_snapshot_ops" to the same colum.
  Address Eric's comments:
  1/5: better commit message.
  5/5: better commit message and comments in code that only one of rollback()
or commit() will be called.

v4:
  5/5: document clean() callback will always be called if it present, declare
static for global variable "actions", use array plus .instance_size to remove
"switch" checking code according to caller input.

Wenchao Xia (5):
  1 block: package preparation code in qmp_transaction()
  2 block: move input parsing code in qmp_transaction()
  3 block: package committing code in qmp_transaction()
  4 block: package rollback code in qmp_transaction()
  5 block: make all steps in qmp_transaction() as callback

 blockdev.c |  263 ++++++++++++++++++++++++++++++++++++++---------------------
 1 files changed, 169 insertions(+), 94 deletions(-)