Re: [Qemu-devel] [PATCH v13 6/6] qcow2: Add full preallocation option

[Kevin Wolf]

Am 29.08.2014 um 10:33 hat Hu Tao geschrieben:
> preallocation=full allocates disk space by fallocating the space if
> posix_fallocate() is available, otherwise by writing zeros to disk to
> ensure disk space in any cases.
> 
> Signed-off-by: Hu Tao <address@hidden>
> ---
>  block/qcow2.c              | 61 
> +++++++++++++++++++++++++++++++++++++++-------
>  qemu-doc.texi              |  7 +++---
>  qemu-img.texi              |  7 +++---
>  tests/qemu-iotests/082.out | 54 ++++++++++++++++++++--------------------
>  4 files changed, 87 insertions(+), 42 deletions(-)

> +        qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
> +                            aligned_total_size + meta_size);
> +        qemu_opt_set(opts, BLOCK_OPT_PREALLOC, 
> PreallocMode_lookup[prealloc]);
> +    }

This means that if used with a protocol that doesn't have a
preallocation option, it gets silently ignored. I'm not completely
decided yet whether that's a bug or a feature. :-)

Kevin