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 00/17] Add qemu-img subcommand to dump file metadata
Date: Tue, 16 Jul 2013 18:57:05 +0200 [thread overview]
Message-ID: <51E57B61.2040606@redhat.com> (raw)
In-Reply-To: <51E57B2A.7050100@redhat.com>
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Il 16/07/2013 18:56, Eric Blake ha scritto:
> On 07/16/2013 10:29 AM, Paolo Bonzini wrote:
>> This series adds a subcommand to "map" that can dump file
>> metadata. Metadata that is dumped includes:
>>
>> - whether blocks are allocated in bs->file and, if so, where
>>
>> - whether blocks are zero
>>
>> - whether data is read from bs or bs->backing_hd
>
> Is this command only usable from qemu-img, or is there a QMP
> counterpart for getting at the same information on a live image
> while qemu is running?
Not yet, we had no use case yet. It may be exposed later to the
guests via the SCSI command GET LBA STATUS.
Paolo
>>
>> Metadata is dumped for an entire chain of images. One example
>> usage is (for non-compressed, non-encrypted images) to transform
>> the metadata into a Linux device-mapper setup, and make a qcow2
>> image available (for read only) as a block device. Another
>> possible usage is to determine the used areas of a file, and
>> convert it in place to another format. Alternatively, the richer
>> data can be used by block jobs to quickly determine if a block is
>> zero without reading it.
>
> Definitely useful information! I haven't looked at the
> implementation yet, but there had better be a JSON representation
> of the output :)
>
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next prev parent reply other threads:[~2013-07-16 16:57 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
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 [this message]
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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