From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Lieven <pl@kamp.de>
Cc: Kevin Wolf <kwolf@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
ronnie sahlberg <ronniesahlberg@gmail.com>
Subject: Re: [Qemu-devel] [PATCHv2 02/11] iscsi: read unmap info from block limits vpd page
Date: Thu, 04 Jul 2013 14:37:00 +0200 [thread overview]
Message-ID: <51D56C6C.60203@redhat.com> (raw)
In-Reply-To: <3E2D40D0-A2C9-4F40-A512-FC917FA13A14@kamp.de>
Il 03/07/2013 23:23, Peter Lieven ha scritto:
> BDC is not used. I had an implementation that sent multiple descriptors out, but
> at least for my storage the maximum unmap counts not for each descriptors, but for all
> together. So in this case we do not need the field at all. I forgot to remove it.
>
> discard and write_zeroes will both only send one request up to max_unmap in size.
>
> apropos write_zeroes: do you know if UNMAP is guaranteed to unmap data if lbprz == 1?
Yes. On the other hand note that WRITE_SAME should be guaranteed _not_
to unmap if lbprz == 0 and you do WRITE_SAME with UNMAP and a zero
payload, but I suspect there may be buggy targets here.
> I have read in the specs something that the target might unmap the blocks or not touch them at all.
> Maybe you have more information.
That's even true of UNMAP itself, actually. :)
The storage can always "upgrade" a block from unmapped to anchored and
from anchored to allocated, so UNMAP can be a no-op and still comply
with the standard.
Paolo
next prev parent reply other threads:[~2013-07-04 12:37 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 13:11 [Qemu-devel] [PATCHv2 00/11] iscsi/qemu-img/block-migration enhancements Peter Lieven
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 01/11] iscsi: add logical block provisioning information to iscsilun Peter Lieven
2013-07-01 13:35 ` Stefan Hajnoczi
2013-07-01 16:08 ` Peter Lieven
2013-07-10 9:19 ` Kevin Wolf
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 02/11] iscsi: read unmap info from block limits vpd page Peter Lieven
2013-07-03 3:43 ` ronnie sahlberg
2013-07-03 21:23 ` Peter Lieven
2013-07-04 12:37 ` Paolo Bonzini [this message]
2013-07-04 21:07 ` Peter Lieven
2013-07-05 6:28 ` Paolo Bonzini
2013-07-05 7:11 ` ronnie sahlberg
2013-07-06 22:15 ` Peter Lieven
2013-07-06 23:23 ` ronnie sahlberg
2013-07-10 9:23 ` Kevin Wolf
2013-07-10 9:25 ` Kevin Wolf
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 03/11] iscsi: add bdrv_co_is_allocated Peter Lieven
2013-07-01 13:46 ` Stefan Hajnoczi
2013-07-01 16:00 ` Peter Lieven
2013-07-10 9:41 ` Kevin Wolf
2013-07-10 13:49 ` Peter Lieven
2013-07-10 14:43 ` Kevin Wolf
2013-07-10 14:49 ` Peter Lieven
2013-07-10 14:54 ` Kevin Wolf
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 04/11] iscsi: add bdrv_co_write_zeroes Peter Lieven
2013-07-10 9:54 ` Kevin Wolf
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 05/11] block: add bdrv_write_zeroes() Peter Lieven
2013-07-10 9:56 ` Kevin Wolf
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 06/11] block/raw: add bdrv_co_write_zeroes Peter Lieven
2013-07-10 9:57 ` Kevin Wolf
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 07/11] iscsi: let bdrv_create conditionally zero out the device Peter Lieven
2013-07-01 13:58 ` Stefan Hajnoczi
2013-07-01 20:20 ` Paolo Bonzini
2013-07-01 21:36 ` Peter Lieven
2013-07-02 9:22 ` Paolo Bonzini
2013-07-02 10:36 ` Peter Lieven
2013-07-02 10:49 ` Paolo Bonzini
2013-07-02 10:56 ` Peter Lieven
2013-07-02 11:04 ` Paolo Bonzini
2013-07-02 11:18 ` Peter Lieven
2013-07-10 10:14 ` Kevin Wolf
2013-07-10 13:52 ` Peter Lieven
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 08/11] block-migration: efficiently encode zero blocks Peter Lieven
2013-07-01 14:13 ` Stefan Hajnoczi
2013-07-01 15:55 ` Peter Lieven
2013-07-02 7:40 ` Stefan Hajnoczi
2013-07-02 10:51 ` Paolo Bonzini
2013-07-01 16:09 ` Peter Lieven
2013-07-02 7:36 ` Stefan Hajnoczi
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 09/11] iscsi: factor out sector conversions Peter Lieven
2013-07-10 11:29 ` Kevin Wolf
2013-07-10 14:07 ` Peter Lieven
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 10/11] iscsi: ignore aio_discard if unsupported Peter Lieven
2013-07-10 11:33 ` Kevin Wolf
2013-07-10 14:04 ` Peter Lieven
2013-07-10 14:28 ` Kevin Wolf
2013-07-10 14:49 ` Peter Lieven
2013-07-10 14:58 ` Kevin Wolf
2013-07-10 20:31 ` Peter Lieven
2013-06-27 13:11 ` [Qemu-devel] [PATCHv2 11/11] iscsi: assert that sectors are aligned to LUN blocksize Peter Lieven
2013-07-01 14:35 ` Stefan Hajnoczi
2013-07-01 15:59 ` Peter Lieven
2013-07-02 7:44 ` Stefan Hajnoczi
2013-07-02 8:28 ` Peter Lieven
2013-07-02 10:44 ` Paolo Bonzini
2013-07-02 10:49 ` Peter Lieven
2013-07-02 10:53 ` Paolo Bonzini
2013-07-10 11:38 ` Kevin Wolf
2013-07-10 14:02 ` Peter Lieven
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