From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Lieven <pl@kamp.de>
Cc: Kevin Wolf <kwolf@redhat.com>,
ronniesahlberg@gmail.com, qemu-devel@nongnu.org,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 7/8] iscsi: assert that sectors are aligned to LUN blocksize
Date: Mon, 24 Jun 2013 18:27:28 +0200 [thread overview]
Message-ID: <51C87370.7060802@redhat.com> (raw)
In-Reply-To: <51C872B4.9050301@kamp.de>
Il 24/06/2013 18:24, Peter Lieven ha scritto:
>> > So far, 4K blocksize is usable if you also specify the same block size
>> > for the guest device. I have posted once the patches to do
>> > read-modify-write, but I never really pursued inclusion of those.
>> >
>> > In any case, the right place to fix this is the block layer;
>> > driver-specific hacks are... hacks. :)
> Where do I find the sector size if not in BDRV_SECTOR_SIZE?
> Is there a dynamic field or is the answer qemu only support 512 Byte
> sector size at the moment?
bdrv_read/write and friends are always in 512-byte units.
There is bs->buffer_alignment for the guest sector size, but it is not
set at bdrv_open, only later. So I think QEMU support for bigger
sectors is too sparse to be useful.
> So you would go for fail to open a device if the LUN blocksize is
> not equal to BDRV_SECTOR_SIZE?
Either that, or fails reads/writes that are not aligned.
Paolo
next prev parent reply other threads:[~2013-06-24 16:27 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-22 20:58 [Qemu-devel] [PATCH 0/8] iscsi/qemu-img/block-migration enhancements Peter Lieven
2013-06-22 20:58 ` [Qemu-devel] [PATCH 1/8] iscsi: add logical block provisioning information to iscsilun Peter Lieven
2013-06-24 14:35 ` Paolo Bonzini
2013-06-22 20:58 ` [Qemu-devel] [PATCH 2/8] iscsi: add bdrv_co_is_allocated Peter Lieven
2013-06-24 14:36 ` Paolo Bonzini
2013-06-22 20:58 ` [Qemu-devel] [PATCH 3/8] iscsi: add bdrv_co_write_zeroes Peter Lieven
2013-06-24 14:34 ` Paolo Bonzini
2013-06-24 16:31 ` Peter Lieven
2013-06-22 20:58 ` [Qemu-devel] [PATCH 4/8] block: add bdrv_write_zeroes() Peter Lieven
2013-06-22 20:58 ` [Qemu-devel] [PATCH 5/8] block/raw: add bdrv_co_write_zeroes Peter Lieven
2013-06-22 20:58 ` [Qemu-devel] [PATCH 6/8] qemu-img: use bdrv_write_zeroes to write zeroes Peter Lieven
2013-06-24 14:33 ` Paolo Bonzini
2013-06-24 16:17 ` Peter Lieven
2013-06-24 16:25 ` Paolo Bonzini
2013-06-24 16:33 ` Peter Lieven
2013-06-24 18:46 ` Peter Lieven
2013-06-22 20:58 ` [Qemu-devel] [PATCH 7/8] iscsi: assert that sectors are aligned to LUN blocksize Peter Lieven
2013-06-24 14:30 ` Paolo Bonzini
2013-06-24 16:10 ` Peter Lieven
2013-06-24 16:13 ` Paolo Bonzini
2013-06-24 16:24 ` Peter Lieven
2013-06-24 16:27 ` Paolo Bonzini [this message]
2013-06-24 16:36 ` Peter Lieven
2013-06-22 20:58 ` [Qemu-devel] [PATCH 8/8] block-migration: efficiently encode zero blocks Peter Lieven
2013-06-24 14:32 ` Paolo Bonzini
2013-06-24 16:14 ` Peter Lieven
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