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authorMax Reitz <mreitz@redhat.com>2017-10-09 23:55:31 +0200
committerMax Reitz <mreitz@redhat.com>2017-10-26 15:01:14 +0200
commite400ad1e1f0127b4fdabcb1c8de1e99be91788df (patch)
tree3cd1d822856c7fc8784b9f70564f9272cb70f480
parent233521b1999810036f63d060ce021d30a8ce0504 (diff)
downloadfocaccia-qemu-e400ad1e1f0127b4fdabcb1c8de1e99be91788df.tar.gz
focaccia-qemu-e400ad1e1f0127b4fdabcb1c8de1e99be91788df.zip
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 <pingl@redhat.com>
Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1414049
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171009215533.12530-2-mreitz@redhat.com
Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
-rw-r--r--block/qcow2.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index d3e114bce5..1ea763126d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3188,6 +3188,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset,
                              "Failed to inquire current file length");
             return old_file_size;
         }
+        old_file_size = ROUND_UP(old_file_size, s->cluster_size);
 
         nb_new_data_clusters = DIV_ROUND_UP(offset - old_length,
                                             s->cluster_size);