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[Qemu-devel] [PATCH v2 3/4] qemu-img: do not zero-pad the compressed wri
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH v2 3/4] qemu-img: do not zero-pad the compressed write buffer |
Date: |
Tue, 16 Apr 2013 11:14:22 +0200 |
bdrv_write_compressed() does not allow requests that span the end of the
device. Therefore it is useless to zero-pad the last cluster and
thereby exceed the end of the device.
Let image formats handle zero-padding the final compressed cluster, if
necessary.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
qemu-img.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index 31627b0..cd096a1 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1425,12 +1425,8 @@ static int img_convert(int argc, char **argv)
}
assert (remainder == 0);
- if (n < cluster_sectors) {
- memset(buf + n * 512, 0, cluster_size - n * 512);
- }
- if (!buffer_is_zero(buf, cluster_size)) {
- ret = bdrv_write_compressed(out_bs, sector_num, buf,
- cluster_sectors);
+ if (!buffer_is_zero(buf, n * BDRV_SECTOR_SIZE)) {
+ ret = bdrv_write_compressed(out_bs, sector_num, buf, n);
if (ret != 0) {
error_report("error while compressing sector %" PRId64
": %s", sector_num, strerror(-ret));
--
1.8.1.4