diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index ad934109a8..fc7d4b185e 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -4242,15 +4242,17 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, * requires a cluster-aligned start. The end may be unaligned if it is * at the end of the image (which it is here). */ - ret = qcow2_cluster_zeroize(bs, zero_start, offset - zero_start, 0); - if (ret < 0) { - error_setg_errno(errp, -ret, "Failed to zero out new clusters"); - goto fail; + if (offset > zero_start) { + ret = qcow2_cluster_zeroize(bs, zero_start, offset - zero_start, 0); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to zero out new clusters"); + goto fail; + } } /* Write explicit zeros for the unaligned head */ if (zero_start > old_length) { - uint64_t len = zero_start - old_length; + uint64_t len = MIN(zero_start, offset) - old_length; uint8_t *buf = qemu_blockalign0(bs, len); QEMUIOVector qiov; qemu_iovec_init_buf(&qiov, buf, len); |