[#LU-7725] Error unpacking OUT message

When I ran replay-dual test_26 with patch ~~LU-7716~~ applied, I can see the complaint as:

LustreError: 24453:0:(layout.c:2025:__req_capsule_get()) @@@ Wrong buffer for field `object_update_reply' (1 of 1) in format `OUT_UPDATE': 0 vs. 4096 (server)

Then I made a patch to catch the debug log and backtrace. This is what I have got.

Pid: 24453, comm: osp_up0-1

Call Trace:
 [<ffffffffa1558875>] libcfs_debug_dumpstack+0x55/0x80 [libcfs]
 [<ffffffffa18c04e5>] __req_capsule_get+0x5b5/0x6f0 [ptlrpc]
 [<ffffffffa18c06dd>] req_capsule_server_sized_get+0x3d/0x50 [ptlrpc]
 [<ffffffffa0dda200>] osp_update_interpret+0x110/0x430 [osp]
 [<ffffffffa188aa54>] ptlrpc_check_set+0x354/0x1c80 [ptlrpc]
 [<ffffffffa188c6fa>] ptlrpc_set_wait+0x37a/0xab0 [ptlrpc]
 [<ffffffff810672b0>] ? default_wake_function+0x0/0x20
 [<ffffffffa1898de5>] ? lustre_msg_set_jobid+0xf5/0x130 [ptlrpc]
 [<ffffffffa188cebe>] ptlrpc_queue_wait+0x8e/0x230 [ptlrpc]
 [<ffffffffa0dda8d5>] osp_send_update_req+0x255/0x880 [osp]
 [<ffffffffa0dd77a6>] ? osp_get_next_request+0xf6/0x1c0 [osp]
 [<ffffffffa0ddb535>] osp_send_update_thread+0x175/0x684 [osp]
 [<ffffffff810672b0>] ? default_wake_function+0x0/0x20
 [<ffffffffa0ddb3c0>] ? osp_send_update_thread+0x0/0x684 [osp]
 [<ffffffff810a0fce>] kthread+0x9e/0xc0
 [<ffffffff8100c28a>] child_rip+0xa/0x20
 [<ffffffff810a0f30>] ? kthread+0x0/0xc0
 [<ffffffff8100c280>] ? child_rip+0x0/0x20

LustreError: dumping log to /tmp/lustre-log.1454116916.24453

[LU-7725] Error unpacking OUT message Created: 30/Jan/16 Updated: 09/Sep/16 Resolved: 09/Feb/16
Status:	Resolved
Project:	Lustre
Component/s:	None
Affects Version/s:	Lustre 2.8.0
Fix Version/s:	Lustre 2.8.0

[LU-7725] Error unpacking OUT message Created: 30/Jan/16 Updated: 09/Sep/16 Resolved: 09/Feb/16