From: Max Reitz Date: Mon, 9 Oct 2017 21:55:31 +0000 (+0200) Subject: qcow2: Fix unaligned preallocated truncation X-Git-Tag: v2.10.2~31 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a25aca75f83895fd16bef572bbf31e33620b600d;p=thirdparty%2Fqemu.git qcow2: Fix unaligned preallocated truncation A qcow2 image file's length is not required to have a length that is a multiple of the cluster size. However, qcow2_refcount_area() expects an aligned value for its @start_offset parameter, so we need to round @old_file_size up to the next cluster boundary. Reported-by: Ping Li Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1414049 Signed-off-by: Max Reitz Message-id: 20171009215533.12530-2-mreitz@redhat.com Cc: qemu-stable@nongnu.org Reviewed-by: Eric Blake Reviewed-by: Jeff Cody Reviewed-by: Stefan Hajnoczi Signed-off-by: Max Reitz (cherry picked from commit e400ad1e1f0127b4fdabcb1c8de1e99be91788df) Signed-off-by: Michael Roth --- diff --git a/block/qcow2.c b/block/qcow2.c index a756bf95414..10e38074adc 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3161,6 +3161,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset, "Failed to inquire current file length"); return ret; } + old_file_size = ROUND_UP(old_file_size, s->cluster_size); nb_new_data_clusters = DIV_ROUND_UP(offset - old_length, s->cluster_size);