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authorNir Soffer <nirsof@gmail.com>2020-07-28 00:58:43 +0300
committerEric Blake <eblake@redhat.com>2020-07-28 09:54:19 -0500
commita2b333c01880f56056d50c238834d62e32001e54 (patch)
tree55207213b626f8b0ceb0ccd5c5865e2c5e0571e6 /qemu-io-cmds.c
parent890cbccb089db9e646cc1baea3be9dc060e3917b (diff)
block: nbd: Fix convert qcow2 compressed to nbd
When converting to qcow2 compressed format, the last step is a special zero length compressed write, ending in a call to bdrv_co_truncate(). This call always fails for the nbd driver since it does not implement bdrv_co_truncate(). For block devices, which have the same limits, the call succeeds since the file driver implements bdrv_co_truncate(). If the caller asked to truncate to the same or smaller size with exact=false, the truncate succeeds. Implement the same logic for nbd. Example failing without this change: In one shell start qemu-nbd: $ truncate -s 1g test.tar $ qemu-nbd --socket=/tmp/nbd.sock --persistent --format=raw --offset 1536 test.tar In another shell convert an image to qcow2 compressed via NBD: $ echo "disk data" > disk.raw $ truncate -s 1g disk.raw $ qemu-img convert -f raw -O qcow2 -c disk1.raw nbd+unix:///?socket=/tmp/nbd.sock; echo $? 1 qemu-img failed, but the conversion was successful: $ qemu-img info nbd+unix:///?socket=/tmp/nbd.sock image: nbd+unix://?socket=/tmp/nbd.sock file format: qcow2 virtual size: 1 GiB (1073741824 bytes) ... $ qemu-img check nbd+unix:///?socket=/tmp/nbd.sock No errors were found on the image. 1/16384 = 0.01% allocated, 100.00% fragmented, 100.00% compressed clusters Image end offset: 393216 $ qemu-img compare disk.raw nbd+unix:///?socket=/tmp/nbd.sock Images are identical. Fixes: https://bugzilla.redhat.com/1860627 Signed-off-by: Nir Soffer <nsoffer@redhat.com> Message-Id: <20200727215846.395443-2-nsoffer@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [eblake: typo fixes] Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'qemu-io-cmds.c')
-rw-r--r--qemu-io-cmds.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 851f07e8f8..baeae86d8c 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -1715,7 +1715,7 @@ static int truncate_f(BlockBackend *blk, int argc, char **argv)
* exact=true. It is better to err on the "emit more errors" side
* than to be overly permissive.
*/
- ret = blk_truncate(blk, offset, true, PREALLOC_MODE_OFF, 0, &local_err);
+ ret = blk_truncate(blk, offset, false, PREALLOC_MODE_OFF, 0, &local_err);
if (ret < 0) {
error_report_err(local_err);
return ret;