[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] Re: [PATCH] block: add logical_block_size property
From: |
Christian Borntraeger |
Subject: |
[Qemu-devel] Re: [PATCH] block: add logical_block_size property |
Date: |
Wed, 17 Mar 2010 10:59:35 +0100 |
User-agent: |
KMail/1.12.4 (Linux/2.6.34-rc1-self-00959-gbca14dd-dirty; KDE/4.3.4; x86_64; ; ) |
Am Donnerstag 04 März 2010 14:20:17 schrieb Christoph Hellwig:
>
> Add a logical block size attribute as various guest side tools only
> increase the filesystem sector size based on it, not the advisory
> physical block size.
>
> For scsi we already have support for a different logical block size
> in place for CDROMs that we can built upon. Only my recent block
> device characteristics VPD page needs some fixups. Note that we
> leave the logial block size for CDROMs hardcoded as the 2k value
> is expected for it in general.
>
> For virtio-blk we already have a feature flag claiming to support
> a variable logical block size that was added for the s390 kuli
> hypervisor. Interestingly it does not actually change the units
> in which the protocol works, which is still fixed at 512 bytes,
> but only communicates a different minimum I/O granularity. So
> all we need to do in virtio is to add a trap for unaligned I/O
> and round down the device size to the next multiple of the logical
> block size.
>
> IDE does not support any other logical block size than 512 bytes.
>
> Signed-off-by: Christoph Hellwig <address@hidden>
Patch looks sane.
Reviewed-by: Christian Borntraeger <address@hidden>