rbd: re-submit flattened write request (part 2)

Add code to rbd_img_obj_exists_callback() to detect when a clone's
parent image has disappeared, and re-submit the original write
request in that case.

Kill off some redundant assertions.

This completes the resolution for:
    http://tracker.ceph.com/issues/3763

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 5c2731859e8acade5214c6224a07219029a0e488..6b872f2197746222be01d8d5be24996341918570 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2516,6 +2516,7 @@ out_err:
 static void rbd_img_obj_exists_callback(struct rbd_obj_request *obj_request)
 {
        struct rbd_obj_request *orig_request;
+       struct rbd_device *rbd_dev;
        int result;
 
        rbd_assert(!obj_request_img_data_test(obj_request));
@@ -2538,8 +2539,21 @@ static void rbd_img_obj_exists_callback(struct rbd_obj_request *obj_request)
                obj_request->xferred, obj_request->length);
        rbd_obj_request_put(obj_request);
 
-       rbd_assert(orig_request);
-       rbd_assert(orig_request->img_request);
+       /*
+        * If the overlap has become 0 (most likely because the
+        * image has been flattened) we need to free the pages
+        * and re-submit the original write request.
+        */
+       rbd_dev = orig_request->img_request->rbd_dev;
+       if (!rbd_dev->parent_overlap) {
+               struct ceph_osd_client *osdc;
+
+               rbd_obj_request_put(orig_request);
+               osdc = &rbd_dev->rbd_client->client->osdc;
+               result = rbd_obj_request_submit(osdc, orig_request);
+               if (!result)
+                       return;
+       }
 
        /*
         * Our only purpose here is to determine whether the object