[Qemu-devel] [RFC PATCH 0/3] Expand 'qemu-img info' to show protocol details

[Eric Blake <eblake@redhat.com>]

Posting this now to get feedback on the general idea; it would still
need to be polished into a form I'd feel happy committing, including
reworking 'qemu-nbd --list' to reuse the new NBD-specific QAPI type.

Based-on: <20190112175812.27068-1-eblake@redhat.com>
[0/19 nbd: add qemu-nbd --list]

Examples with this applied:
$ ./qemu-img info file
image: file
file format: qcow2
virtual size: 1.0M (1048576 bytes)
disk size: 672K
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false
Protocol specific information:
    write zero: true
    discard zero: true
    discard: true
    align: 1
$ qemu-nbd file &
$ ./qemu-img info nbd://localhost:10809
image: nbd://localhost:10809
file format: raw
virtual size: 1.0M (1048576 bytes)
disk size: unavailable
Protocol specific information:
    flags:
    active contexts:
        [0]:
            name: base:allocation
            id: 0
    unknown flags: 1260

Eric Blake (3):
  block: Expose protocol-specific data to 'qemu-img info'
  file: Expose some protocol-specific information
  RFC: nbd: Expose protocol-specific information

 qapi/block-core.json | 87 +++++++++++++++++++++++++++++++++++++++++++-
 block/nbd-client.h   |  1 +
 block/file-posix.c   | 21 +++++++++++
 block/nbd-client.c   | 39 ++++++++++++++++++++
 block/nbd.c          |  3 ++
 block/qapi.c         |  7 ++++
 6 files changed, 156 insertions(+), 2 deletions(-)

-- 
2.20.1