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From: Paolo Bonzini <pbonzini@redhat.com>
To: Eric Blake <eblake@redhat.com>
Cc: famz@redhat.com, pl@kamp.de, qemu-devel@nongnu.org, stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 08/17] block: make bdrv_has_zero_init return false for copy-on-write-images
Date: Fri, 19 Jul 2013 15:23:39 +0200	[thread overview]
Message-ID: <51E93DDB.6070708@redhat.com> (raw)
In-Reply-To: <51E93D41.4010601@redhat.com>

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Il 19/07/2013 15:21, Eric Blake ha scritto:
> Question (more for my understanding, not that you need to change
> code): must we blindly return 0 in the presence of a backing file,
> or is it possible to recursively query the backing_hd's zero_init
> status, allowing us to return 1 iff all files in the chain support
> zero_init.

No, it's really blind.  bdrv_has_zero_init is like "was the image all
zeros at creation time", and the answer is no because the content of
the image used to be the same as the backing_hd.

Paolo
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  reply	other threads:[~2013-07-19 13:23 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-16 16:29 [Qemu-devel] [PATCH v2 00/17] Add qemu-img subcommand to dump file metadata Paolo Bonzini
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 01/17] cow: make reads go at a decent speed Paolo Bonzini
2013-07-19 12:31   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 02/17] cow: make writes go at a less indecent speed Paolo Bonzini
2013-07-19 12:40   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 03/17] cow: do not call bdrv_co_is_allocated Paolo Bonzini
2013-07-19 12:42   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 04/17] block: make bdrv_co_is_allocated static Paolo Bonzini
2013-07-19 12:44   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 05/17] block: remove bdrv_is_allocated_above/bdrv_co_is_allocated_above distinction Paolo Bonzini
2013-07-19 12:46   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 06/17] block: expect errors from bdrv_co_is_allocated Paolo Bonzini
2013-07-19 12:57   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 07/17] qemu-img: always probe the input image for allocated sectors Paolo Bonzini
2013-07-19 13:05   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 08/17] block: make bdrv_has_zero_init return false for copy-on-write-images Paolo Bonzini
2013-07-19 13:21   ` Eric Blake
2013-07-19 13:23     ` Paolo Bonzini [this message]
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 09/17] block: introduce bdrv_get_block_status API Paolo Bonzini
2013-07-19 13:43   ` Eric Blake
2013-07-25 12:13     ` Paolo Bonzini
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 10/17] block: define get_block_status return value Paolo Bonzini
2013-07-19  6:35   ` Peter Lieven
2013-07-19  9:14     ` Paolo Bonzini
2013-07-19  6:48   ` Peter Lieven
2013-07-19  9:12     ` Paolo Bonzini
2013-07-19  9:58     ` Paolo Bonzini
2013-07-19 10:04       ` Peter Lieven
2013-07-19 12:13         ` Paolo Bonzini
2013-07-19 13:06           ` Peter Lieven
2013-07-20  7:00             ` Paolo Bonzini
2013-07-23 21:18               ` Peter Lieven
2013-07-19 16:52   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 11/17] block: return get_block_status data and flags for formats Paolo Bonzini
2013-07-19 19:25   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 12/17] qemu-img: add a "map" subcommand Paolo Bonzini
2013-07-18  7:25   ` Fam Zheng
2013-07-18  8:55     ` Paolo Bonzini
2013-07-19 19:36   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 13/17] block: use bdrv_has_zero_init to return BDRV_BLOCK_ZERO Paolo Bonzini
2013-07-17 17:50   ` Peter Lieven
2013-07-19 19:37   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 14/17] raw-posix: return get_block_status data and flags Paolo Bonzini
2013-07-19 19:48   ` Eric Blake
2013-07-25 12:16     ` Paolo Bonzini
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 15/17] raw-posix: detect XFS unwritten extents Paolo Bonzini
2013-07-19 20:10   ` Eric Blake
2013-08-02 15:05   ` Christoph Hellwig
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 16/17] block: add default get_block_status implementation for protocols Paolo Bonzini
2013-07-19 20:11   ` Eric Blake
2013-07-16 16:29 ` [Qemu-devel] [PATCH v2 17/17] block: look for zero blocks in bs->file Paolo Bonzini
2013-07-19  7:33   ` Stefan Hajnoczi
2013-07-19 17:07     ` Paolo Bonzini
2013-07-23 21:18       ` Peter Lieven
2013-07-19 20:12   ` Eric Blake
2013-07-16 16:56 ` [Qemu-devel] [PATCH v2 00/17] Add qemu-img subcommand to dump file metadata Eric Blake
2013-07-16 16:57   ` Paolo Bonzini
2013-07-19 10:48     ` Wenchao Xia
2013-07-19 12:14       ` Paolo Bonzini
2013-07-20  0:19         ` Wenchao Xia
2013-07-18  8:17 ` Peter Lieven
2013-07-18  8:58   ` Paolo Bonzini
2013-07-19  4:45 ` Stefan Hajnoczi
2013-07-19  7:34 ` Stefan Hajnoczi

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