diff options
| author | Peter Lieven <pl@kamp.de> | 2013-10-24 12:07:06 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2013-11-28 10:30:52 +0100 |
| commit | 5a37b60a61c4c334e3b194758871f41494317d42 (patch) | |
| tree | f8c169029b78de6fa1012b4f94ccf02ae174a34d | |
| parent | 11b6699af59b8684128debacfc7c44cbaa6ac53b (diff) | |
qemu-img: conditionally zero out target on convert
If the target has_zero_init = 0, but supports efficiently
writing zeroes by unmapping we call bdrv_make_zero to
avoid fully allocating the target. This currently works
only for iscsi. It can be extended to raw with
BLKDISCARDZEROES for example.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | qemu-img.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/qemu-img.c b/qemu-img.c index cc3fed7b44..dc0c2f0ed3 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1355,7 +1355,7 @@ static int img_convert(int argc, char **argv) } } - flags = BDRV_O_RDWR; + flags = min_sparse ? (BDRV_O_RDWR | BDRV_O_UNMAP) : BDRV_O_RDWR; ret = bdrv_parse_cache_flags(cache, &flags); if (ret < 0) { error_report("Invalid cache option: %s", cache); @@ -1471,6 +1471,14 @@ static int img_convert(int argc, char **argv) } else { int has_zero_init = min_sparse ? bdrv_has_zero_init(out_bs) : 0; + if (!has_zero_init && bdrv_can_write_zeroes_with_unmap(out_bs)) { + ret = bdrv_make_zero(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) { |