On Fri, Dec 27, 2013 at 11:05:53AM +0800, Hu Tao wrote:
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 6f6b8c1..a722d27 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1160,17 +1160,52 @@ 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);
> + if (ret < 0) {
> + ret = -errno;
> + }
> +
> + /* fallback to posix_fallocate() if fallocate() is not supported */
> + if (ret == -ENOSYS || ret == -EOPNOTSUPP) {
> + ret = posix_fallocate(fd, offset, length);
> + }
> +
> + return ret;
> +}
Why is this Linux-specific #ifdef necessary? glibc will try to use the
fallocate(2) system call, if possible.
Stefan
