Re: [Qemu-devel] [RFC PATCH v2 3/6] block/raw-posix: implement bdrv_preallocate

[Fam Zheng]

On 2013年11月27日 10:15, Hu Tao wrote:
> Signed-off-by: Hu Tao <address@hidden>
> ---
>   block/raw-posix.c | 34 ++++++++++++++++++++++++++++++++++
>   1 file changed, 34 insertions(+)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index f836c8e..c563073 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1050,6 +1050,39 @@ static int64_t 
> raw_get_allocated_file_size(BlockDriverState *bs)
>       return (int64_t)st.st_blocks * 512;
>   }
>
> +#ifdef __linux__
> +static int raw_preallocate2(int fd, int64_t offset, int64_t length)
> +{
> +    int ret = -1;
> +
> +    ret = fallocate(fd, 0, offset, length);
> +
> +    /* fallback to posix_fallocate() if fallocate() is not supported */
> +    if (ret < 0 && (errno == ENOSYS || errno == EOPNOTSUPP)) {
> +        ret = posix_fallocate(fd, offset, length);
> +    }
> +
> +    return ret;
> +}
> +#else
> +static int raw_preallocate2(int fd, int64_t offset, int64_t length)
> +{
> +    return posix_fallocate(fd, offset, length);
> +}
> +#endif
> +
> +static int raw_preallocate(BlockDriverState *bs, int64_t offset, int64_t 
> length)
> +{
> +    BDRVRawState *s = bs->opaque;
> +    int64_t len = bdrv_getlength(bs);
> +
> +    if (offset + length < 0 || offset + length > len) {
> +        return -1;

-EINVAL

Fam

> +    }
> +
> +    return raw_preallocate2(s->fd, offset, length);
> +}
> +
>   static int raw_create(const char *filename, QEMUOptionParameter *options,
>                         Error **errp)
>   {
> @@ -1221,6 +1254,7 @@ static BlockDriver bdrv_file = {
>       .bdrv_close = raw_close,
>       .bdrv_create = raw_create,
>       .bdrv_has_zero_init = bdrv_has_zero_init_1,
> +    .bdrv_preallocate = raw_preallocate,
>       .bdrv_co_get_block_status = raw_co_get_block_status,
>
>       .bdrv_aio_readv = raw_aio_readv,