[PATCH 4.0 50/72] rbd: end I/O the entire obj_request on error

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ilya Dryomov <idryomov@gmail.com>

commit 082a75dad84d79d1c15ea9e50f31cb4bb4fa7fd6 upstream.

When we end I/O struct request with error, we need to pass
obj_request->length as @nr_bytes so that the entire obj_request worth
of bytes is completed.  Otherwise block layer ends up confused and we
trip on

    rbd_assert(more ^ (which == img_request->obj_request_count));

in rbd_img_obj_callback() due to more being true no matter what.  We
already do it in most cases but we are missing some, in particular
those where we don't even get a chance to submit any obj_requests, due
to an early -ENOMEM for example.

A number of obj_request->xferred assignments seem to be redundant but
I haven't touched any of obj_request->xferred stuff to keep this small
and isolated.

Cc: Alex Elder <elder@linaro.org>
Reported-by: Shawn Edwards <lesser.evil@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/rbd.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2264,6 +2264,11 @@ static bool rbd_img_obj_end_request(stru
 			result, xferred);
 		if (!img_request->result)
 			img_request->result = result;
+		/*
+		 * Need to end I/O on the entire obj_request worth of
+		 * bytes in case of error.
+		 */
+		xferred = obj_request->length;
 	}
 
 	/* Image object requests don't own their page array */