[Qemu-devel] [PATCH v4 0/2] Report format specific info for LUKS block driver

["Daniel P. Berrange" <berrange@redhat.com>]

This is a followup to:

  v1: https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg01723.html
  v2: https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg03642.html
  v3: https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg03885.html

The 'qemu-img info' tool has ability to print format specific
information, eg with qcow2 it reports two extra items:

  $ qemu-img info ~/VirtualMachines/demo.qcow2
  image: /home/berrange/VirtualMachines/demo.qcow2
  file format: qcow2
  virtual size: 3.0G (3221225472 bytes)
  disk size: 140K
  cluster_size: 65536
  Format specific information:
      compat: 0.10
      refcount bits: 16


This is not currently wired up for the LUKS driver. This patch
series adds that support so that we can report useful data about
the LUKS volume such as the crypto algorithm choices, key slot
usage and other volume metadata.

The first patch extends the crypto API to allow querying of the
format specific metadata

The second patches extends the block API to allow the LUKS driver
to report the format specific metadata.

    $ qemu-img info ~/VirtualMachines/demo.luks
    image: /home/berrange/VirtualMachines/demo.luks
    file format: luks
    virtual size: 98M (102760448 bytes)
    disk size: 100M
    encrypted: yes
    Format specific information:
        ivgen alg: plain64
        hash alg: sha1
        cipher alg: aes-128
        uuid: 6ddee74b-3a22-408c-8909-6789d4fa2594
        cipher mode: xts
        slots:
            [0]:
                active: true
                iters: 572706
                key offset: 4096
                stripes: 4000
            [1]:
                active: false
                key offset: 135168
            [2]:
                active: false
                key offset: 266240
            [3]:
                active: false
                key offset: 397312
            [4]:
                active: false
                key offset: 528384
            [5]:
                active: false
                key offset: 659456
            [6]:
                active: false
                key offset: 790528
            [7]:
                active: false
                key offset: 921600
        payload offset: 2097152
        master key iters: 142375

Technically most of the code changes here are in the crypto
layer, rather than the block layer. I'm fine with both patches
going through the block maintainer tree, or can submit a both
patches myself as, for sake of simplicity of merge.

Changed in v4:

 - Introduce an empty QCryptoBlockInfoQCow struct to keep
   QAPI generator happy (Eric)

Changed in v3:

 - Do full struct copy instead of field-by-field copy (Max)
 - Simplify handling of linked list pointers (Max)
 - Use g_strndup with uuid to guarantee null termination (Max)
 - Misc typos (Max)

Changed in v2:

 - Drop patches related to creating a text output visitor to
   format the ImageInfoSpecific data. This will be continued
   in a separate patch series
 - Fix key offset to be in bytes instead of sectors
 - Drop the duplicated ImageInfoSpecificLUKS type and just
   directly use QCryptoBlockInfoLUKS type in block layer
 - Skip reporting stripes/iters if keyslot is inactive
 - Add missing QAPI schema docs




Daniel P. Berrange (2):
  crypto: add support for querying parameters for block encryption
  block: export LUKS specific data to qemu-img info

 block/crypto.c         | 49 ++++++++++++++++++++++++++++
 crypto/block-luks.c    | 67 ++++++++++++++++++++++++++++++++++++++
 crypto/block.c         | 17 ++++++++++
 crypto/blockpriv.h     |  4 +++
 include/crypto/block.h | 16 ++++++++++
 qapi/block-core.json   |  6 +++-
 qapi/crypto.json       | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 245 insertions(+), 1 deletion(-)

-- 
2.7.4