From: Paolo Bonzini <pbonzini@redhat.com>
To: ronnie sahlberg <ronniesahlberg@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Peter Lieven <pl@kamp.de>,
qemu-devel <qemu-devel@nongnu.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 4/4] qemu-img: conditionally discard target on convert
Date: Thu, 18 Jul 2013 16:14:36 +0200 [thread overview]
Message-ID: <51E7F84C.2080705@redhat.com> (raw)
In-Reply-To: <CAN05THS-Fm6A2_kjZ0JOgHR9P5Cy_8OZNdv=EozdUUxssY0yAg@mail.gmail.com>
Il 18/07/2013 15:55, ronnie sahlberg ha scritto:
>> > bdrv->write_zeroes will use writesame16 and set the unmap flag only if
>> > BDRV_MAY_DISCARD == 1 and BDRV_O_UNMAP == 1 and lbprz == 1.
> When you use WRITESAME16 you can ignore the lbprz flag.
> Just send a WRITESAME16 command with one block of data that is all set to zero.
> If the unmap flag is set and if unmapped blocks read back the same as
> the block you provided (all zero)
> then it will unmap those blocks, where possible.
True, so the unmap flag can be set iff BDRV_MAY_DISCARD == 1. block.c
can take care of checking BDRV_O_UNMAP.
Paolo
> All other blocks that can not be unmapped, or where unmapped blocks
> will not read back the same, will instead be overwritten by the
> provided all-zero block.
>
>
next prev parent reply other threads:[~2013-07-18 14:14 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-15 10:49 [Qemu-devel] [PATCH 0/4] qemu-img: conditionally discard target on convert Peter Lieven
2013-07-15 10:49 ` [Qemu-devel] [PATCH 1/4] block: add discard_zeroes and max_unmap to BlockDriverInfo Peter Lieven
2013-07-15 10:49 ` [Qemu-devel] [PATCH 2/4] iscsi: add .bdrv_get_info Peter Lieven
2013-07-15 10:49 ` [Qemu-devel] [PATCH 3/4] block/raw: " Peter Lieven
2013-07-19 5:12 ` Stefan Hajnoczi
2013-07-15 10:49 ` [Qemu-devel] [PATCH 4/4] qemu-img: conditionally discard target on convert Peter Lieven
2013-07-17 8:46 ` Kevin Wolf
2013-07-17 9:58 ` Paolo Bonzini
2013-07-17 10:21 ` Peter Lieven
2013-07-17 10:27 ` Kevin Wolf
2013-07-17 10:31 ` Peter Lieven
2013-07-17 10:47 ` Paolo Bonzini
2013-07-17 14:19 ` Peter Lieven
2013-07-17 10:45 ` Paolo Bonzini
2013-07-17 14:21 ` Peter Lieven
2013-07-17 14:26 ` Paolo Bonzini
2013-07-17 10:25 ` Kevin Wolf
2013-07-17 15:54 ` ronnie sahlberg
2013-07-17 16:27 ` Paolo Bonzini
2013-07-17 16:31 ` ronnie sahlberg
2013-07-17 17:02 ` Peter Lieven
2013-07-17 17:04 ` Paolo Bonzini
2013-07-17 17:48 ` Peter Lieven
2013-07-17 20:00 ` Paolo Bonzini
2013-07-18 9:23 ` Kevin Wolf
2013-07-18 10:24 ` Paolo Bonzini
2013-07-18 10:42 ` Kevin Wolf
2013-07-18 10:44 ` Peter Lieven
2013-07-18 10:56 ` Paolo Bonzini
2013-07-18 11:04 ` Peter Lieven
2013-07-18 12:31 ` Paolo Bonzini
2013-07-18 13:29 ` Peter Lieven
2013-07-18 13:52 ` Paolo Bonzini
2013-07-18 14:09 ` Peter Lieven
2013-07-18 14:20 ` Paolo Bonzini
2013-07-18 14:32 ` Peter Lieven
2013-07-18 14:35 ` Paolo Bonzini
2013-07-18 18:43 ` Peter Lieven
2013-07-18 18:54 ` ronnie sahlberg
2013-07-18 19:28 ` Peter Lieven
2013-07-19 5:58 ` Paolo Bonzini
2013-07-19 6:08 ` Peter Lieven
2013-07-19 13:25 ` ronnie sahlberg
2013-07-19 13:49 ` Peter Lieven
2013-07-19 14:00 ` ronnie sahlberg
2013-07-19 14:02 ` Peter Lieven
2013-07-19 13:58 ` ronnie sahlberg
2013-07-18 13:55 ` ronnie sahlberg
2013-07-18 14:14 ` Paolo Bonzini [this message]
2013-09-12 8:52 ` Peter Lieven
2013-09-12 8:55 ` Paolo Bonzini
2013-09-12 9:03 ` Peter Lieven
2013-07-17 17:09 ` ronnie sahlberg
2013-07-18 9:21 ` Kevin Wolf
2013-07-17 10:22 ` Peter Lieven
2013-07-16 10:55 ` [Qemu-devel] [PATCH 0/4] " Paolo Bonzini
2013-07-16 11:18 ` Peter Lieven
2013-07-16 11:27 ` Paolo Bonzini
2013-07-16 11:40 ` Peter Lieven
2013-07-16 11:55 ` Paolo Bonzini
2013-07-17 10:23 ` Peter Lieven
2013-07-17 10:28 ` Paolo Bonzini
2013-07-17 10:40 ` Peter Lieven
2013-07-17 10:50 ` Paolo Bonzini
2013-07-17 14:18 ` Peter Lieven
2013-07-17 14:26 ` Paolo Bonzini
2013-07-17 14:46 ` Peter Lieven
2013-07-17 14:53 ` Paolo Bonzini
2013-07-17 15:12 ` Kevin Wolf
2013-07-17 16:53 ` Peter Lieven
2013-07-17 17:01 ` Peter Lieven
2013-07-19 5:13 ` Stefan Hajnoczi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51E7F84C.2080705@redhat.com \
--to=pbonzini@redhat.com \
--cc=kwolf@redhat.com \
--cc=pl@kamp.de \
--cc=qemu-devel@nongnu.org \
--cc=ronniesahlberg@gmail.com \
--cc=stefanha@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).