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-rw-r--r--drivers/block/rbd.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 3327192bb71f..c8fb886aebd4 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3038,6 +3038,17 @@ again:
}
return true;
case RBD_OBJ_READ_PARENT:
+ /*
+ * The parent image is read only up to the overlap -- zero-fill
+ * from the overlap to the end of the request.
+ */
+ if (!*result) {
+ u32 obj_overlap = rbd_obj_img_extents_bytes(obj_req);
+
+ if (obj_overlap < obj_req->ex.oe_len)
+ rbd_obj_zero_range(obj_req, obj_overlap,
+ obj_req->ex.oe_len - obj_overlap);
+ }
return true;
default:
BUG();