[Qemu-block] [PATCH v6 00/15] qemu-img map: Allow driver to return file of the allocated block

[Fam Zheng]

v6: Two more changes as suggested by Max:
    - Fix comments of BDRV_BLOCK_OFFSET_VALID and BDRV_BLOCK_DATA;
    - Really keep 102 working;
    - Add rev-by in patch 11.

v5: Address Max's review comments:
    - "It's" -> "Its" in commit message in patch 1;
    - Retain the "bs->file" condition to unbreak iotest 102 in patch 1;
    - Fix comment of BDRV_BLOCK_OFFSET_VALID in patch 1;
    - Fix VMDK's compressed case in patch 11;
    - Add patch 12 in complement of patch 1.

v4: Rebase and resend, adding Eric's and Stefan's reviewed-by.

    Fix one typo in patch 13.

    Drop previous patch 14 for a later rework because it is not a hard
    requirement, but it is pending on Eric's QAPI-to-JSON visitor series:

    https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg03929.html

Original cover letter
---------------------

I stumbled upon this when looking at external bitmap formats.

Current "qemu-img map" command only displays filename if the data is allocated
in bs (bs->file) itself, or in the backing chain. Otherwise, it displays an
unfriendly error message:

    $ qemu-img create -f vmdk -o subformat=monolithicFlat /tmp/test.vmdk 1G

    $ qemu-img map /tmp/test.vmdk
    Offset          Length          Mapped to       File
    qemu-img: File contains external, encrypted or compressed clusters.

This can be improved. This series extends the .bdrv_co_get_block_status
callback, to let block driver return the BDS of file; then updates all driver
to implement it; and lastly, it changes qemu-img to use this information in
"map" command:


    $ qemu-img map /tmp/test.vmdk
    Offset          Length          Mapped to       File
    0               0x40000000      0               /tmp/test-flat.vmdk

    $ qemu-img map --output json /tmp/test.vmdk
    [{"length": 1073741824, "start": 0, "zero": false, "offset": 0, "depth": 0,
      "file": "/tmp/test-flat.vmdk", "data": true}
    ]


Fam Zheng (15):
  block: Add "file" output parameter to block status query functions
  qcow: Assign bs->file->bs to file in qcow_co_get_block_status
  qcow2: Assign bs->file->bs to file in qcow2_co_get_block_status
  raw: Assign bs to file in raw_co_get_block_status
  iscsi: Assign bs to file in iscsi_co_get_block_status
  parallels: Assign bs->file->bs to file in
    parallels_co_get_block_status
  qed: Assign bs->file->bs to file in bdrv_qed_co_get_block_status
  sheepdog: Assign bs to file in sd_co_get_block_status
  vdi: Assign bs->file->bs to file in vdi_co_get_block_status
  vpc: Assign bs->file->bs to file in vpc_co_get_block_status
  vmdk: Return extent's file in bdrv_get_block_status
  block: Use returned *file in bdrv_co_get_block_status
  qemu-img: In "map", use the returned "file" from bdrv_get_block_status
  qemu-img: Make MapEntry a QAPI struct
  iotests: Add "qemu-img map" test for VMDK extents

 block/io.c                 | 42 ++++++++++++++++---------
 block/iscsi.c              |  9 ++++--
 block/mirror.c             |  3 +-
 block/parallels.c          |  3 +-
 block/qcow.c               |  3 +-
 block/qcow2.c              |  3 +-
 block/qed.c                |  6 +++-
 block/raw-posix.c          |  4 ++-
 block/raw_bsd.c            |  4 ++-
 block/sheepdog.c           |  5 ++-
 block/vdi.c                |  3 +-
 block/vmdk.c               | 12 ++++---
 block/vpc.c                |  4 ++-
 block/vvfat.c              |  2 +-
 include/block/block.h      | 11 ++++---
 include/block/block_int.h  |  3 +-
 qapi/block-core.json       | 27 ++++++++++++++++
 qemu-img.c                 | 78 ++++++++++++++++++++++++++++------------------
 tests/qemu-iotests/059     | 10 ++++++
 tests/qemu-iotests/059.out | 38 ++++++++++++++++++++++
 20 files changed, 202 insertions(+), 68 deletions(-)

-- 
2.4.3