@@ -1375,6 +1375,14 @@ static bool obj_request_exists_test(struct rbd_obj_request *obj_request)
return test_bit(OBJ_REQ_EXISTS, &obj_request->flags) != 0;
}
+static bool obj_request_overlaps_parent(struct rbd_obj_request *obj_request)
+{
+ struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
+
+ return obj_request->img_offset <
+ round_up(rbd_dev->parent_overlap, rbd_obj_bytes(&rbd_dev->header));
+}
+
static void rbd_obj_request_get(struct rbd_obj_request *obj_request)
{
dout("%s: obj %p (was %d)\n", __func__, obj_request,
@@ -2662,7 +2670,7 @@ static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request)
*/
if (!img_request_write_test(img_request) ||
!img_request_layered_test(img_request) ||
- rbd_dev->parent_overlap <= obj_request->img_offset ||
+ !obj_request_overlaps_parent(obj_request) ||
((known = obj_request_known_test(obj_request)) &&
obj_request_exists_test(obj_request))) {
This is a note to let you know that I have just added a patch titled rbd: handle parent_overlap on writes correctly to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.11.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From e67746585f37c25bedc64d367697c45eef226e82 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov <ilya.dryomov@inktank.com> Date: Tue, 10 Jun 2014 13:53:29 +0400 Subject: rbd: handle parent_overlap on writes correctly commit 9638556a276125553549fdfe349c464481ec2f39 upstream. The following check in rbd_img_obj_request_submit() rbd_dev->parent_overlap <= obj_request->img_offset allows the fall through to the non-layered write case even if both parent_overlap and obj_request->img_offset belong to the same RADOS object. This leads to data corruption, because the area to the left of parent_overlap ends up unconditionally zero-filled instead of being populated with parent data. Suppose we want to write 1M to offset 6M of image bar, which is a clone of foo@snap; object_size is 4M, parent_overlap is 5M: rbd_data.<id>.0000000000000001 ---------------------|----------------------|------------ | should be copyup'ed | should be zeroed out | write ... ---------------------|----------------------|------------ 4M 5M 6M parent_overlap obj_request->img_offset 4..5M should be copyup'ed from foo, yet it is zero-filled, just like 5..6M is. Given that the only striping mode kernel client currently supports is chunking (i.e. stripe_unit == object_size, stripe_count == 1), round parent_overlap up to the next object boundary for the purposes of the overlap check. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/block/rbd.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) -- 1.9.1