[Qemu-devel] [PATCHv6 00/17] block: logical block provisioning enhancements

[Peter Lieven]

this patch adds the ability for targets to stay sparse during
block migration (if the zero_blocks capability is set) and qemu-img convert
even if the target does not have has_zero_init = 1.

the series was especially developed for iSCSI, but it should also work
with other drivers with little or no adjustments. these adjustments
should be limited to providing block provisioning information through
get_block_info and/or honouring BDRV_REQ_MAY_UNMAP on writing zeroes.

v5->v6:
 - protected iscsi_co_write_zeroes by the existence of the
   SCSI_SENSE_ASCQ_CAPACITY_DATA_HAS_CHANGED macro. This is ugly
   but necessary because the semantic of iscsi_writesame16_task
   silently changed between libiscsi 1.8.0 and 1.9.0. The above
   macro was the first added after the change. I already contacted
   Ronnie to introduce an API version macro which has to be bumped
   on each new function that will be added. Changes to the parameters
   should not happen at all of course.

v4->v5:
 - new patches 4-6 to move the block provisioning information
   to the BlockDriverInfo.
 - kept 2 wrappers to read the information from the BDI and
   renamed them to make more clear what they do:

 bdrv_has_discard_zeroes -> bdrv_unallocated_blocks_are_zero
 bdrv_has_discard_write_zeroes -> bdrv_can_write_zeroes_with_unmap

 - added additional information about the 2 flags in the
   BDI struct in block.h

v3->v4:
 - changed BlockLimits struct to typedef (Stefan, Eric)
 - renamed bdrv_zeroize to bdrv_make_zero (Stefan)
 - added comment about the -S flag of qemu-img convert in
   qemu-img.texi (Eric)
 - used struct assignment for bs->bl in raw_open (Stefan, Eric)
 - dropped 3 get_block_status fixes that are independent of
   this series and already partly merged.

v2->v3:
 - fix merge conflict in block/qcow2_cluster.c
 - changed return type of bdrv_has_discard_zeroes and
   bdrv_has_discard_write_zeroes to bool.
 - moved alignment and limits info to a BlockLimits struct (Paolo).
 - added magic constanst for default maximum in bdrv_co_do_write_zeroes
   and bdrv_co_discard (Eric).
 - bdrv_co_do_write_zeroes: allocating the bounce buffer only once (Eric),
   fixed bounce iov_len in the fall back path.
 - bdrv_zeroize: added inline docu (Eric) and do not mask flags passed
   to bdrv_write_zeroes (Eric).
 - qemu-img: changed the default hint for -S (min_sparse) in the usage
   help to 4k. not changing the default as it is unclear why this default
   was set. size suffixes are already supported (Eric).

v1->v2:
 - moved block max_discard and max_write_zeroes to BlockDriverState
 - added discard_alignment and write_zeroes_alignment to BlockDriverState
 - added bdrv_has_discard_zeroes() and bdrv_has_discard_write_zeroes()
 - added logic to bdrv_co_discard and bdrv_co_do_write_zeroes to honour
   limit and alignment info.
 - added support for -S 0 in qemu-img convert.

Peter Lieven (17):
  block: make BdrvRequestFlags public
  block: add flags to bdrv_*_write_zeroes
  block: introduce BDRV_REQ_MAY_UNMAP request flag
  block: add logical block provisioning info to BlockDriverInfo
  block: add wrappers for logical block provisioning information
  block/iscsi: add .bdrv_get_info
  block: add BlockLimits structure to BlockDriverState
  block: honour BlockLimits in bdrv_co_do_write_zeroes
  block: honour BlockLimits in bdrv_co_discard
  iscsi: simplify iscsi_co_discard
  iscsi: set limits in BlockDriverState
  iscsi: add bdrv_co_write_zeroes
  block: introduce bdrv_make_zero
  block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks
  qemu-img: add support for fully allocated images
  qemu-img: conditionally zero out target on convert
  block/raw: copy BlockLimits on raw_open

Peter Lieven (17):
  block: make BdrvRequestFlags public
  block: add flags to bdrv_*_write_zeroes
  block: introduce BDRV_REQ_MAY_UNMAP request flag
  block: add logical block provisioning info to BlockDriverInfo
  block: add wrappers for logical block provisioning information
  block/iscsi: add .bdrv_get_info
  block: add BlockLimits structure to BlockDriverState
  block: honour BlockLimits in bdrv_co_do_write_zeroes
  block: honour BlockLimits in bdrv_co_discard
  iscsi: simplify iscsi_co_discard
  iscsi: set limits in BlockDriverState
  iscsi: add bdrv_co_write_zeroes
  block: introduce bdrv_make_zero
  block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks
  qemu-img: add support for fully allocated images
  qemu-img: conditionally zero out target on convert
  block/raw: copy BlockLimits on raw_open

 block-migration.c         |    3 +-
 block.c                   |  200 +++++++++++++++++++++++++++++++++++++--------
 block/backup.c            |    3 +-
 block/iscsi.c             |  150 +++++++++++++++++++++++++---------
 block/qcow2-cluster.c     |    2 +-
 block/qcow2.c             |    2 +-
 block/qed.c               |    3 +-
 block/raw_bsd.c           |    6 +-
 block/vmdk.c              |    3 +-
 include/block/block.h     |   35 +++++++-
 include/block/block_int.h |   19 ++++-
 qemu-img.c                |   18 +++-
 qemu-img.texi             |    5 ++
 qemu-io-cmds.c            |    2 +-
 14 files changed, 363 insertions(+), 88 deletions(-)

-- 
1.7.9.5