[Qemu-devel] [PATCH v6 0/6] Provide additional info through qemu-img info

[Max Reitz <mreitz@redhat.com>]

qemu-img info provides only pretty general information about an image.
For any image format, there might be specific options which cannot be
represented in a universal way; for instance, qcow2 provides the
compatibility and lazy_refcount options whose values are certainly
interesting but currently cannot be output by qemu-img info.

Therefore, this series adds a new ImageInfoSpecific union type to
ImageInfo which may be used by block drivers as a template for new types
dedicated to the specific information they can provide, as well as a
function bdrv_get_specific_info for retrieving this information. It also
adds support to qemu-img info and qemu-io -c info to print the content
of these specific structures.

v6:
 - implemented Eric's remarks:
   - corrected description of ImageInfo in qapi-schema.json (patch 1)
   - added root indentation in bdrv_image_info_specific_dump (patch 3);
     Although this is a very minor change, I dropped Eric's Reviewed-by
     because of it, since I'm not sure myself whether the place I've
     added the indentation is actually the right one (maybe the caller
     of bdrv_image_info_specific_dump should control the indentation
     instead of hardcoding it into the function).
     Furthermore, this (his) suggestion was not part of his review for
     this patch, but for patch 6.
   - changed patch 5 from using some non-portable expressions to fully
     bash-specific ones
   - use $() instead of `` and $PWD instead of `pwd` in patch 6 and
     indent format specific information in reference output (according
     to change in patch 3)
 - rebased on Kevin's block branch (changed some line numbers and the
   diff environment in patch 5)

v5:
 - In consideration of Stefan's argument about bdrv_round_to_cluster
   being called in the I/O path, removed ImageInfoSpecific from
   BlockDriverInfo and introduced a new function bdrv_get_specific_info
   instead; this also removes the need for bdrv_put_info.
   Resulting changes in regard to the single patches:
    - patch 2: completely different
    - patch 3: qemu-io-cmds.c:info_f now needs to call
      bdrv_get_specific_info in order to receive the new information
    - patch 4: moved the creation of ImageInfoSpecific from qcow2_get_info
      (which now remains unmodified) to the new qcow2_get_specific_info
      function; additionally, register this function as
      bdrv_qcow2.bdrv_get_specific_info
 - rebased on Kevin's block branch, renamed test from 064 to 065 (to
   avoid conflict with his blockdev-add series; affects patch 6)
 - patches 1 and 5 remain unmodified

v4:
 - changed dirty "grep -A 42" for grepping all lines until EOF in test
   064 to cleaner "sed -n '//,$p'" (patch 6)
 - rebased on Kevin's block branch (affects line numbers in patches 2, 3
   and 4 as well as the group file change in patch 6)

v3:
 - implemented Fam's remarks:
   - bdrv_get_info already initializes all fields to NULL, no need to do
     this manually (patch 2)
   - implemented bdrv_put_info as a wrapper to
     qapi_free_ImageInfoSpecific, though this may change with further
     extensions to BlockDriverInfo (patch 2)
   - changed one occurence of puts("foo") to printf("foo\n") in order to
     be consistent with the surrounding code (patch 3)
   - other patches (1, 4, 5, 6) remain unmodified

v2:
 - following Eric's recommendation: changed the representation of the
   format specific information from an uninterpreted blobbed string to a
   union of format specific types

Max Reitz (6):
  qapi: Add ImageInfoSpecific type
  block: Add bdrv_get_specific_info
  block/qapi: Human-readable ImageInfoSpecific dump
  qcow2: Add support for ImageInfoSpecific
  qemu-iotests: Discard specific info in _img_info
  qemu-iotests: Additional info from qemu-img info

 block.c                      |   9 ++++
 block/qapi.c                 | 124 +++++++++++++++++++++++++++++++++++++++++++
 block/qcow2.c                |  19 +++++++
 include/block/block.h        |   1 +
 include/block/block_int.h    |   1 +
 include/block/qapi.h         |   2 +
 qapi-schema.json             |  34 +++++++++++-
 qemu-io-cmds.c               |   9 ++++
 tests/qemu-iotests/065       |  72 +++++++++++++++++++++++++
 tests/qemu-iotests/065.out   |  22 ++++++++
 tests/qemu-iotests/common.rc |  20 ++++++-
 tests/qemu-iotests/group     |   1 +
 12 files changed, 312 insertions(+), 2 deletions(-)
 create mode 100755 tests/qemu-iotests/065
 create mode 100644 tests/qemu-iotests/065.out

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1.8.3.1