[Qemu-devel] [PATCH v6 0/8] Implement reference count for BlockDriverState

[Fam Zheng <famz@redhat.com>]

BlockDriverState lifecycle management is needed by future features such as
image fleecing and blockdev-add. This series adds reference count to
BlockDriverState.

The first two patches clean up two odd BlockDriverState use cases, so all code
uses bdrv_new() to create BlockDriverState instance.

Then implemented bdrv_ref() and bdrv_unref() to operate on refcnt: Initially,
refcnt is 1, which means bdrv_unref is effectively a bdrv_delete() here. So
patch 04 has a search and replace to convert bdrv_delete to bdrv_unref, before
bdrv_ref is used anywhere. 05~08 patches calls bdrv_ref for device attach,
block-migration and nbd.

The rule is: Either bdrv_ref() or bdrv_new() must have a matching
bdrv_unref() call, and the last matching bdrv_unref deletes the bs.

v6:
    08: Use BH to release reference, this fixes the iotest.

v5: resend v4 to a right list.

v4:
    08: Added, let block job use BDS reference.
    02: Fix leak of bs.opaque

v3:
    03: Removed unnecessary bdrv_close() call.

v2:
    05: Removed: "block: use BlockDriverState refcnt for device attach/detach"
    07: Fix xen_disk blk_disconnect() as it depended on device attach refcnt.


Fam Zheng (8):
  vvfat: use bdrv_new() to allocate BlockDriverState
  iscsi: use bdrv_new() instead of stack structure
  block: implement reference count for BlockDriverState
  block: make bdrv_delete() static
  migration: omit drive ref as we have bdrv_ref now
  xen_disk: simplify blk_disconnect with refcnt
  nbd: use BlockDriverState refcnt
  block: use BDS ref for block jobs

 block-migration.c         |  4 +--
 block.c                   | 44 ++++++++++++++++++++++++---------
 block/backup.c            |  2 +-
 block/blkverify.c         |  4 +--
 block/cow.c               |  2 +-
 block/iscsi.c             | 16 ++++++------
 block/mirror.c            |  2 +-
 block/qcow.c              |  2 +-
 block/qcow2.c             |  2 +-
 block/qed.c               |  2 +-
 block/sheepdog.c          |  6 ++---
 block/snapshot.c          |  2 +-
 block/stream.c            |  2 +-
 block/vmdk.c              | 10 ++++----
 block/vvfat.c             |  6 ++---
 blockdev-nbd.c            | 10 +-------
 blockdev.c                | 63 +++++++++++++++++------------------------------
 blockjob.c                |  1 +
 hw/block/xen_disk.c       | 13 +++++-----
 include/block/block.h     |  3 ++-
 include/block/block_int.h |  1 +
 nbd.c                     |  5 ++++
 qemu-img.c                | 26 +++++++++----------
 qemu-io.c                 |  6 ++---
 24 files changed, 119 insertions(+), 115 deletions(-)

-- 
1.8.3.1