Re: [Qemu-devel] [PATCH v4 00/20] add byte-based block_status driver callbacks

[Vladimir Sementsov-Ogievskiy]

Most of conversions looks fine, but it is not simple to prove the
correctness, because we start to use internal driver logic on offsets
and lengths, not aligned to sectors. And we can't imagine the
consequences (at least, I can't and my r-b doesn't give the guarantee)
of such change. It is like take some function and expand its scope of
parameters.

May be I'm too paranoiac. May be it would be good to align requests
in bdrv_co_block_status to sectors at least for drivers which do not
provide request_alignment. May be each patch should be reviewed by
person, knowing that particular driver.



12.10.2017 21:58, Eric Blake wrote:
> There are patches floating around to add NBD_CMD_BLOCK_STATUS,
> but NBD wants to report status on byte granularity (even if the
> reporting will probably be naturally aligned to sectors or even
> much higher levels).  I've therefore started the task of
> converting our block status code to report at a byte granularity
> rather than sectors.
>
> Now that 2.11 is open, I'm rebasing/reposting the remaining patches.
>
> The overall conversion currently looks like:
> part 1: bdrv_is_allocated (merged, commit 51b0a488)
> part 2: dirty-bitmap (merged, commit ca759622)
> part 3: bdrv_get_block_status (v6 is posted [1], partially reviewed)
> part 4: .bdrv_co_block_status (this series, v3 was here [2])
>
> Available as a tag at:
> git fetch git://repo.or.cz/qemu/ericb.git nbd-byte-callback-v4
>
> Based-on: <address@hidden>
> ([PATCH v6 00/24] make bdrv_get_block_status byte-based)
>
> Since v3:
> - rebase to series 3 tweak in get_status interface
> - further simplify qed code
> - better documentation of optimization flag (s/mapping/want_zero/)
>
> 001/20:[0033] [FC] 'block: Add .bdrv_co_block_status() callback'
> 002/20:[0077] [FC] 'block: Switch passthrough drivers to 
> .bdrv_co_block_status()'
> 003/20:[0020] [FC] 'file-posix: Switch to .bdrv_co_block_status()'
> 004/20:[0019] [FC] 'gluster: Switch to .bdrv_co_block_status()'
> 005/20:[----] [--] 'iscsi: Switch cluster_sectors to byte-based'
> 006/20:[----] [--] 'iscsi: Switch iscsi_allocmap_update() to byte-based'
> 007/20:[0022] [FC] 'iscsi: Switch to .bdrv_co_block_status()'
> 008/20:[0013] [FC] 'null: Switch to .bdrv_co_block_status()'
> 009/20:[0017] [FC] 'parallels: Switch to .bdrv_co_block_status()'
> 010/20:[0014] [FC] 'qcow: Switch to .bdrv_co_block_status()'
> 011/20:[0019] [FC] 'qcow2: Switch to .bdrv_co_block_status()'
> 012/20:[0086] [FC] 'qed: Switch to .bdrv_co_block_status()'
> 013/20:[0015] [FC] 'raw: Switch to .bdrv_co_block_status()'
> 014/20:[0011] [FC] 'sheepdog: Switch to .bdrv_co_block_status()'
> 015/20:[----] [--] 'vdi: Avoid bitrot of debugging code'
> 016/20:[0017] [FC] 'vdi: Switch to .bdrv_co_block_status()'
> 017/20:[0013] [FC] 'vmdk: Switch to .bdrv_co_block_status()'
> 018/20:[0019] [FC] 'vpc: Switch to .bdrv_co_block_status()'
> 019/20:[0010] [FC] 'vvfat: Switch to .bdrv_co_block_status()'
> 020/20:[0019] [FC] 'block: Drop unused .bdrv_co_get_block_status()'
>
> Eric Blake (20):
>    block: Add .bdrv_co_block_status() callback
>    block: Switch passthrough drivers to .bdrv_co_block_status()
>    file-posix: Switch to .bdrv_co_block_status()
>    gluster: Switch to .bdrv_co_block_status()
>    iscsi: Switch cluster_sectors to byte-based
>    iscsi: Switch iscsi_allocmap_update() to byte-based
>    iscsi: Switch to .bdrv_co_block_status()
>    null: Switch to .bdrv_co_block_status()
>    parallels: Switch to .bdrv_co_block_status()
>    qcow: Switch to .bdrv_co_block_status()
>    qcow2: Switch to .bdrv_co_block_status()
>    qed: Switch to .bdrv_co_block_status()
>    raw: Switch to .bdrv_co_block_status()
>    sheepdog: Switch to .bdrv_co_block_status()
>    vdi: Avoid bitrot of debugging code
>    vdi: Switch to .bdrv_co_block_status()
>    vmdk: Switch to .bdrv_co_block_status()
>    vpc: Switch to .bdrv_co_block_status()
>    vvfat: Switch to .bdrv_co_block_status()
>    block: Drop unused .bdrv_co_get_block_status()
>
>   include/block/block.h     |   9 ++-
>   include/block/block_int.h |  43 +++++++------
>   block/io.c                |  80 +++++++++++-------------
>   block/blkdebug.c          |  20 +++---
>   block/commit.c            |   2 +-
>   block/file-posix.c        |  59 ++++++++++--------
>   block/gluster.c           |  67 +++++++++++---------
>   block/iscsi.c             | 154 +++++++++++++++++++++++++---------------------
>   block/mirror.c            |   2 +-
>   block/null.c              |  23 +++----
>   block/parallels.c         |  22 ++++---
>   block/qcow.c              |  27 ++++----
>   block/qcow2.c             |  24 ++++----
>   block/qed.c               |  84 +++++++++----------------
>   block/raw-format.c        |  16 ++---
>   block/sheepdog.c          |  26 ++++----
>   block/throttle.c          |   2 +-
>   block/vdi.c               |  45 +++++++-------
>   block/vmdk.c              |  28 ++++-----
>   block/vpc.c               |  42 +++++++------
>   block/vvfat.c             |  16 +++--
>   21 files changed, 404 insertions(+), 387 deletions(-)


--
Best regards,
Vladimir