[PATCH v2 0/4] block: fix detect-zeroes= with BDRV_REQ_REGISTERED_BUF

[Stefan Hajnoczi <stefanha@redhat.com>]

v2:
- Add comment explaining unbalanced error code path in
  qemu_io_alloc_from_file() [Eric]
- List options alphabetically in help output [Eric]
- Add Tested-by/Reviewed-by
- CC qemu-stable on the fix

The first patch fixes a regression in QEMU 7.2 where detect-zeroes breaks with
virtio-blk devices due to a BDRV_REQ_REGISTERED_BUF bug. Details of the
regression can be found here:
https://gitlab.com/qemu-project/qemu/-/issues/1404

The remaining patches add a regression test that will protect this code path in
the future. The qemu-io command is extended with the new -r option that calls
blk_register_buf(). This allows a qemu-iotests test case to trigger the same
bug as virtio-blk.

Stefan Hajnoczi (4):
  block: fix detect-zeroes= with BDRV_REQ_REGISTERED_BUF
  qemu-io: use BdrvRequestFlags instead of int
  qemu-io: add -r option to register I/O buffer
  iotests/detect-zeroes-registered-buf: add new test

 block/io.c                                    |   3 +
 qemu-io-cmds.c                                | 180 ++++++++++++------
 .../tests/detect-zeroes-registered-buf        |  58 ++++++
 .../tests/detect-zeroes-registered-buf.out    |   7 +
 4 files changed, 189 insertions(+), 59 deletions(-)
 create mode 100755 tests/qemu-iotests/tests/detect-zeroes-registered-buf
 create mode 100644 tests/qemu-iotests/tests/detect-zeroes-registered-buf.out

-- 
2.39.1