1 files changed, 85 insertions, 12 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 5c129c54279c..13a381b2a779 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -398,6 +398,8 @@ void rbd_warn(struct rbd_device *rbd_dev, const char *fmt, ...)
 #  define rbd_assert(expr)      ((void) 0)
 #endif /* !RBD_DEBUG */
 
+static void rbd_img_parent_read(struct rbd_obj_request *obj_request);
+
 static int rbd_dev_refresh(struct rbd_device *rbd_dev, u64 *hver);
 static int rbd_dev_v2_refresh(struct rbd_device *rbd_dev, u64 *hver);
 
@@ -1336,9 +1338,15 @@ static void rbd_osd_trivial_callback(struct rbd_obj_request *obj_request)
 
 static void rbd_osd_read_callback(struct rbd_obj_request *obj_request)
 {
-        dout("%s: obj %p result %d %llu/%llu\n", __func__, obj_request,
-                obj_request->result, obj_request->xferred, obj_request->length);
-        if (obj_request->img_request)
+        struct rbd_img_request *img_request = obj_request->img_request;
+        bool layered = img_request && img_request_layered_test(img_request);
+
+        dout("%s: obj %p img %p result %d %llu/%llu\n", __func__,
+                obj_request, img_request, obj_request->result,
+                obj_request->xferred, obj_request->length);
+        if (layered && obj_request->result == -ENOENT)
+                rbd_img_parent_read(obj_request);
+        else if (img_request)
                 rbd_img_obj_request_read_callback(obj_request);
         else
                 obj_request_done_set(obj_request);
@@ -1349,9 +1357,8 @@ static void rbd_osd_write_callback(struct rbd_obj_request *obj_request)
         dout("%s: obj %p result %d %llu\n", __func__, obj_request,
                 obj_request->result, obj_request->length);
         /*
-         * There is no such thing as a successful short write.
-         * Our xferred value is the number of bytes transferred
-         * back.  Set it to our originally-requested length.
+         * There is no such thing as a successful short write.  Set
+         * it to our originally-requested length.
          */
         obj_request->xferred = obj_request->length;
         obj_request_done_set(obj_request);
@@ -1391,7 +1398,7 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req,
          * passed to blk_end_request(), which takes an unsigned int.
          */
         obj_request->xferred = osd_req->r_reply_op_len[0];
-        rbd_assert(obj_request->xferred < (u64) UINT_MAX);
+        rbd_assert(obj_request->xferred < (u64)UINT_MAX);
         opcode = osd_req->r_ops[0].op;
         switch (opcode) {
         case CEPH_OSD_OP_READ:
@@ -1607,7 +1614,6 @@ static struct rbd_img_request *rbd_img_request_create(
         INIT_LIST_HEAD(&img_request->obj_requests);
         kref_init(&img_request->kref);
 
-        (void) img_request_layered_test(img_request);   /* Avoid a warning */
         rbd_img_request_get(img_request);       /* Avoid a warning */
         rbd_img_request_put(img_request);       /* TEMPORARY */
 
@@ -1635,6 +1641,9 @@ static void rbd_img_request_destroy(struct kref *kref)
         if (img_request_write_test(img_request))
                 ceph_put_snap_context(img_request->snapc);
 
+        if (img_request_child_test(img_request))
+                rbd_obj_request_put(img_request->obj_request);
+
         kfree(img_request);
 }
 
@@ -1643,13 +1652,11 @@ static bool rbd_img_obj_end_request(struct rbd_obj_request *obj_request)
         struct rbd_img_request *img_request;
         unsigned int xferred;
         int result;
+        bool more;
 
         rbd_assert(obj_request_img_data_test(obj_request));
         img_request = obj_request->img_request;
 
-        rbd_assert(!img_request_child_test(img_request));
-        rbd_assert(img_request->rq != NULL);
-
         rbd_assert(obj_request->xferred <= (u64)UINT_MAX);
         xferred = (unsigned int)obj_request->xferred;
         result = obj_request->result;
@@ -1666,7 +1673,15 @@ static bool rbd_img_obj_end_request(struct rbd_obj_request *obj_request)
                         img_request->result = result;
         }
 
-        return blk_end_request(img_request->rq, result, xferred);
+        if (img_request_child_test(img_request)) {
+                rbd_assert(img_request->obj_request != NULL);
+                more = obj_request->which < img_request->obj_request_count - 1;
+        } else {
+                rbd_assert(img_request->rq != NULL);
+                more = blk_end_request(img_request->rq, result, xferred);
+        }
+
+        return more;
 }
 
 static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
@@ -1811,6 +1826,64 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request)
         return 0;
 }
 
+static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
+{
+        struct rbd_obj_request *obj_request;
+
+        rbd_assert(img_request_child_test(img_request));
+
+        obj_request = img_request->obj_request;
+        rbd_assert(obj_request != NULL);
+        obj_request->result = img_request->result;
+        obj_request->xferred = img_request->xferred;
+
+        rbd_img_obj_request_read_callback(obj_request);
+        rbd_obj_request_complete(obj_request);
+}
+
+static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
+{
+        struct rbd_device *rbd_dev;
+        struct rbd_img_request *img_request;
+        int result;
+
+        rbd_assert(obj_request_img_data_test(obj_request));
+        rbd_assert(obj_request->img_request != NULL);
+        rbd_assert(obj_request->result == (s32) -ENOENT);
+        rbd_assert(obj_request->type == OBJ_REQUEST_BIO);
+
+        rbd_dev = obj_request->img_request->rbd_dev;
+        rbd_assert(rbd_dev->parent != NULL);
+        /* rbd_read_finish(obj_request, obj_request->length); */
+        img_request = rbd_img_request_create(rbd_dev->parent,
+                                                obj_request->img_offset,
+                                                obj_request->length,
+                                                false, true);
+        result = -ENOMEM;
+        if (!img_request)
+                goto out_err;
+
+        rbd_obj_request_get(obj_request);
+        img_request->obj_request = obj_request;
+
+        result = rbd_img_request_fill_bio(img_request, obj_request->bio_list);
+        if (result)
+                goto out_err;
+
+        img_request->callback = rbd_img_parent_read_callback;
+        result = rbd_img_request_submit(img_request);
+        if (result)
+                goto out_err;
+
+        return;
+out_err:
+        if (img_request)
+                rbd_img_request_put(img_request);
+        obj_request->result = result;
+        obj_request->xferred = 0;
+        obj_request_done_set(obj_request);
+}
+
 static int rbd_obj_notify_ack(struct rbd_device *rbd_dev,
                                    u64 ver, u64 notify_id)
 {