Re: [Qemu-devel] [PATCH v7 2/8] qmp: Add optional bool "unmap" to drive-mirror

[Eric Blake <eblake@redhat.com>]

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On 06/07/2015 11:56 PM, Fam Zheng wrote:
> If specified as "true", it allows discarding on target sectors where source is
> not allocated.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/mirror.c            | 8 ++++++--
>  blockdev.c                | 5 +++++
>  hmp.c                     | 2 +-
>  include/block/block_int.h | 2 ++
>  qapi/block-core.json      | 8 +++++++-
>  qmp-commands.hx           | 3 +++
>  6 files changed, 24 insertions(+), 4 deletions(-)
> 

> +++ b/qapi/block-core.json
> @@ -973,6 +973,11 @@
>  # @on-target-error: #optional the action to take on an error on the target,
>  #                   default 'report' (no limitations, since this applies to
>  #                   a different block device than @device).
> +# @unmap: #optional Whether to try to unmap target sectors where source has
> +#         only zero. If true, and target unallocated sectors will read as zero,
> +#         target image sectors will be unmapped; otherwise, zeroes will be
> +#         written. Both will result in identical contents.
> +#         Default is true. (Since 2.4)
>  #

Per the other thread on adding 'detect-zeroes', should we instead be
using an enum here that describes one of several behaviors without an
explosion into multiple knobs?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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