Re: [Qemu-devel] [PATCH v3 0/2] Optimize alignment probing

[Nir Soffer <nsoffer@redhat.com>]

Adding Eric

On Tue, Aug 27, 2019 at 4:05 AM Nir Soffer <nirsof@gmail.com> wrote:

> When probing unallocated area on remote XFS filesystem we cannot detect
> request
> alignment and we fallback to safe value which may not be optimal. Avoid
> this
> fallback by always allocating the first block when creating a new image or
> resizing empty image.
>
> Tested with all formats:
>
>     for fmt in raw bochs cloop parallels qcow qcow2 qed vdi vpc vhdx vmdk
> luks dmg; do
>         ./check -$fmt
>     done
>
> Changes in v3:
> - Allocating first block works now when 512 <= size < 4096, storage sector
> size
>   is 512 bytes, and using block_resize with O_DIRECT (Max)
> - Fix return value on errors if qemu_vfree() modified errno (Eric)
> - Improve comment about using allocate_first_block in FALLOC mode (Max)
> - Remove unneeded $(()) in _filter_block (Max)
> - Add _default_cache_mode and _supported_cache_mode to new test (Max)
> - Fix disk size in vmdk tests
>
> v2 was here:
> https://lists.nongnu.org/archive/html/qemu-block/2019-08/msg01265.html
>
> Changes in v2:
> - Support file descriptor opened with O_DIRECT (e.g. in block_resize) (Max)
> - Remove unneeded change in 160 (Max)
> - Fix block filter in 175 on filesystem allocating extra blocks (Max)
> - Comment why we ignore errors in allocte_first_block() (Max)
> - Comment why allocate_first_block() is needed in FALLOC mode (Max)
> - Clarify commit message about user visible changes (Maxim)
> - Fix 178.out.qcow2
> - Fix 150.out with -qcow2 by splitting to 150.out.{raw,qcow2}
> - Add test for allocate_first_block() with block_resize (Max)
> - Drop provisioning tests results since I ran them only once
>
> v1 was here:
> https://lists.nongnu.org/archive/html/qemu-block/2019-08/msg00821.html
>
> Nir Soffer (2):
>   block: posix: Always allocate the first block
>   iotests: Test allocate_first_block() with O_DIRECT
>
>  block/file-posix.c                            | 51 +++++++++++++++++++
>  tests/qemu-iotests/059.out                    |  2 +-
>  tests/qemu-iotests/{150.out => 150.out.qcow2} |  0
>  tests/qemu-iotests/150.out.raw                | 12 +++++
>  tests/qemu-iotests/175                        | 47 ++++++++++++++---
>  tests/qemu-iotests/175.out                    | 16 ++++--
>  tests/qemu-iotests/178.out.qcow2              |  4 +-
>  tests/qemu-iotests/221.out                    | 12 +++--
>  tests/qemu-iotests/253.out                    | 12 +++--
>  9 files changed, 135 insertions(+), 21 deletions(-)
>  rename tests/qemu-iotests/{150.out => 150.out.qcow2} (100%)
>  create mode 100644 tests/qemu-iotests/150.out.raw
>
> --
> 2.20.1
>
>