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

From: Greg Kroah-Hartman
Date: Mon May 11 2015 - 14:57:17 EST

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


From: Ilya Dryomov <idryomov@xxxxxxxxx>

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@xxxxxxxxxx>
Reported-by: Shawn Edwards <lesser.evil@xxxxxxxxx>
Reviewed-by: Sage Weil <sage@xxxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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 */

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