rbd: record overall image request result

If any image object request produces a non-zero result, preserve
that as the result of the overall image request.  If multiple
objects have non-zero results, save only the first one.

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 503e64f51fe17c191974b3b53d6b7e109c7264c0..69eab66b6c670e8bb4881ba3115f6ce218b8fff5 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -214,6 +214,7 @@ struct rbd_img_request {
        spinlock_t              completion_lock;/* protects next_completion */
        u32                     next_completion;
        rbd_img_callback_t      callback;
+       int                     result; /* first nonzero obj_request result */
 
        u32                     obj_request_count;
        struct list_head        obj_requests;   /* rbd_obj_request structs */
@@ -1488,6 +1489,7 @@ static struct rbd_img_request *rbd_img_request_create(
        spin_lock_init(&img_request->completion_lock);
        img_request->next_completion = 0;
        img_request->callback = NULL;
+       img_request->result = 0;
        img_request->obj_request_count = 0;
        INIT_LIST_HEAD(&img_request->obj_requests);
        kref_init(&img_request->kref);
@@ -1552,13 +1554,16 @@ static void rbd_img_obj_callback(struct rbd_obj_request *obj_request)
                if (!obj_request_done_test(obj_request))
                        break;
 
-               rbd_assert(obj_request->xferred <= (u64) UINT_MAX);
-               xferred = (unsigned int) obj_request->xferred;
-               result = (int) obj_request->result;
-               if (result)
+               rbd_assert(obj_request->xferred <= (u64)UINT_MAX);
+               xferred = (unsigned int)obj_request->xferred;
+               result = obj_request->result;
+               if (result) {
                        rbd_warn(NULL, "obj_request %s result %d xferred %u\n",
                                img_request->write_request ? "write" : "read",
                                result, xferred);
+                       if (!img_request->result)
+                               img_request->result = result;
+               }
 
                more = blk_end_request(img_request->rq, result, xferred);
                which++;