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Re: [Qemu-devel] [PATCH v2 2/6] file-win32: Switch to byte-based callbac
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v2 2/6] file-win32: Switch to byte-based callbacks |
Date: |
Wed, 25 Apr 2018 12:57:08 +0200 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
Am 24.04.2018 um 21:25 hat Eric Blake geschrieben:
> We are gradually moving away from sector-based interfaces, towards
> byte-based. Make the change for the last few sector-based callbacks
> in the file-win32 driver.
>
> Note that the driver was already using byte-based calls for
> performing actual I/O, so this just gets rid of a round trip
> of scaling; however, as I don't know if Windows is tolerant of
> non-sector AIO operations, I went with the conservative approach
> of modifying .bdrv_refresh_limits to override the block layer
> defaults back to the pre-patch value of 512.
>
> Signed-off-by: Eric Blake <address@hidden>
> ---
> Compile-tested via 'make address@hidden', but I don't
> have a sane way to test whether it actually works.
Tried to test it, and the only result is that something was broken even
before your patch:
$ ./qemu-img.exe create -f raw /tmp/test.raw 128M
Formatting '/tmp/test.raw', fmt=raw size=134217728
$ ./qemu-io.exe -f raw -c 'read 0 4k' /tmp/test.raw
read failed: Input/output error
For some reason, doing the same with qcow2 works fine. qemu-iotests
for qcow2 starts hanging in 013. Maybe someone should look into this,
qemu-iotests was working fairly well with mingw builds some time ago.
Nothing that will hold up this series, though.
Kevin
- [Qemu-devel] [PATCH v2 0/6] block: byte-based AIO read/write, Eric Blake, 2018/04/24
- [Qemu-devel] [PATCH v2 5/6] vxhs: Switch to byte-based callbacks, Eric Blake, 2018/04/24
- [Qemu-devel] [PATCH v2 4/6] rbd: Switch to byte-based callbacks, Eric Blake, 2018/04/24
- [Qemu-devel] [PATCH v2 3/6] null: Switch to byte-based read/write, Eric Blake, 2018/04/24
- [Qemu-devel] [PATCH v2 1/6] block: Support byte-based aio callbacks, Eric Blake, 2018/04/24
- [Qemu-devel] [PATCH v2 2/6] file-win32: Switch to byte-based callbacks, Eric Blake, 2018/04/24
- Re: [Qemu-devel] [PATCH v2 2/6] file-win32: Switch to byte-based callbacks,
Kevin Wolf <=
- [Qemu-devel] [PATCH v2 6/6] block: Drop last of the sector-based aio callbacks, Eric Blake, 2018/04/24
- Re: [Qemu-devel] [PATCH v2 0/6] block: byte-based AIO read/write, Kevin Wolf, 2018/04/25