block/qcow2-bitmap: Don't check size for IN_USE bitmap

We are going to allow image resize when there are persistent bitmaps.
It may lead to appearing of inconsistent bitmaps (IN_USE=1) with
inconsistent size. But we still want to load them as inconsistent.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190311185147.52309-3-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>

1 files changed, 18 insertions, 3 deletions

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 885f36c..92cef1c 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -462,10 +462,25 @@ static int check_dir_entry(BlockDriverState *bs, Qcow2BitmapDirEntry *entry)
         return len;
     }
 
-    fail = (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) ||
-           (len > ((phys_bitmap_bytes * 8) << entry->granularity_bits));
+    if (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) {
+        return -EINVAL;
+    }
 
-    return fail ? -EINVAL : 0;
+    if (!(entry->flags & BME_FLAG_IN_USE) &&
+        (len > ((phys_bitmap_bytes * 8) << entry->granularity_bits)))
+    {
+        /*
+         * We've loaded a valid bitmap (IN_USE not set) or we are going to
+         * store a valid bitmap, but the allocated bitmap table size is not
+         * enough to store this bitmap.
+         *
+         * Note, that it's OK to have an invalid bitmap with invalid size due
+         * to a bitmap that was not correctly saved after image resize.
+         */
+        return -EINVAL;
+    }
+
+    return 0;
 }
 
 static inline void bitmap_directory_to_be(uint8_t *dir, size_t size)