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Re: [Qemu-devel] [PATCH v2 08/17] block: make bdrv_has_zero_init return
From: |
Paolo Bonzini |
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 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 |
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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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- [Qemu-devel] [PATCH v2 01/17] cow: make reads go at a decent speed, (continued)
- [Qemu-devel] [PATCH v2 01/17] cow: make reads go at a decent speed, Paolo Bonzini, 2013/07/16
- [Qemu-devel] [PATCH v2 02/17] cow: make writes go at a less indecent speed, Paolo Bonzini, 2013/07/16
- [Qemu-devel] [PATCH v2 03/17] cow: do not call bdrv_co_is_allocated, Paolo Bonzini, 2013/07/16
- [Qemu-devel] [PATCH v2 04/17] block: make bdrv_co_is_allocated static, Paolo Bonzini, 2013/07/16
- [Qemu-devel] [PATCH v2 08/17] block: make bdrv_has_zero_init return false for copy-on-write-images, Paolo Bonzini, 2013/07/16
- [Qemu-devel] [PATCH v2 09/17] block: introduce bdrv_get_block_status API, Paolo Bonzini, 2013/07/16
- [Qemu-devel] [PATCH v2 10/17] block: define get_block_status return value, Paolo Bonzini, 2013/07/16