diff mbox series

[2/3] qcow2: Fix qcow2_alloc_cluster_abort() for external data file

Message ID 20200211094900.17315-3-kwolf@redhat.com (mailing list archive)
State New, archived
Headers show
Series qcow2: Fix write/copy error path with data file | expand

Commit Message

Kevin Wolf Feb. 11, 2020, 9:48 a.m. UTC
For external data file, cluster allocations return an offset in the data
file and are not refcounted. In this case, there is nothing to do for
qcow2_alloc_cluster_abort(). Freeing the same offset in the qcow2 file
is wrong and causes crashes in the better case or image corruption in
the worse case.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2-cluster.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 8982b7b762..dc3c270226 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1015,8 +1015,11 @@  err:
 void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m)
 {
     BDRVQcow2State *s = bs->opaque;
-    qcow2_free_clusters(bs, m->alloc_offset, m->nb_clusters << s->cluster_bits,
-                        QCOW2_DISCARD_NEVER);
+    if (!has_data_file(bs)) {
+        qcow2_free_clusters(bs, m->alloc_offset,
+                            m->nb_clusters << s->cluster_bits,
+                            QCOW2_DISCARD_NEVER);
+    }
 }
 
 /*