Il 13/09/2013 12:25, Peter Lieven ha scritto:
> if the target has_zero_init = 0, but supports efficiently
> writing zeroes by unmapping we call bdrv_zeroize to
> avoid fully allocating the target. this currently
> is designed especially for iscsi.
>
> Signed-off-by: Peter Lieven <p...@kamp.de>
> ---
> qemu-img.c | 22 ++++++++++++++++------
> 1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/qemu-img.c b/qemu-img.c
> index 3e5e388..6eaddc6 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -1354,7 +1354,8 @@ static int img_convert(int argc, char **argv)
> }
> }
>
> - flags = BDRV_O_RDWR;
> + flags = BDRV_O_RDWR | BDRV_O_UNMAP;
I think this should be a new command-line flag.
Paolo
> +
> ret = bdrv_parse_cache_flags(cache, &flags);
> if (ret < 0) {
> error_report("Invalid cache option: %s", cache);
> @@ -1386,12 +1387,13 @@ static int img_convert(int argc, char **argv)
> }
> }
>
> + ret = bdrv_get_info(out_bs, &bdi);
> + if (ret < 0) {
> + error_report("could not get block driver info");
> + goto out;
> + }
> +
> if (compress) {
> - ret = bdrv_get_info(out_bs, &bdi);
> - if (ret < 0) {
> - error_report("could not get block driver info");
> - goto out;
> - }
> cluster_size = bdi.cluster_size;
> if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE) {
> error_report("invalid cluster size");
> @@ -1470,6 +1472,14 @@ static int img_convert(int argc, char **argv)
> } else {
> int has_zero_init = bdrv_has_zero_init(out_bs);
>
> + if (!has_zero_init && !out_baseimg && bdi.discard_write_zeroes) {
> + ret = bdrv_zeroize(out_bs, BDRV_REQ_MAY_UNMAP);
> + if (ret < 0) {
> + goto out;
> + }
> + has_zero_init = 1;
> + }
> +
> sector_num = 0; // total number of sectors converted so far
> nb_sectors = total_sectors - sector_num;
> if (nb_sectors != 0) {
>
