LU-4558 clio: Solve a race in cl_lock_put

It's not atomic to check the last reference and state of cl_lock
in cl_lock_put(). This can cause a problem that an using lock is
freed, if the process is preempted between atomic_dec_and_test()
and (lock->cll_state == CLS_FREEING).

This problem can be solved by holding a refcount by coh_locks. In
this case, it can be sure that if the lock refcount reaches zero,
nobody else can have any chance to use it again.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: I08b81bcd6a4040ea9608db97d60aa6706405ee8c
LLNL-Bug: TOSS-2479
LU-3949 llite: debug patch to track umount

print debug info in Lustre operations called by VFS during umount
to track where and when the umount began and completed.

Change-Id: Id504bc75c0c5e80ff926d1bdb567549a6f7a8dff
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Patch-Set: 1
LLNL-Bug: TOSS-2274
LU-4245 ldlm: do not fill empty lvbo buffer

Don't fill empty lvbo buffer if server does not prepare it.

Lustre-change: http://review.whamcloud.com/8285
Lustre-commit: bcbc62ea3e957f80238f326543eb46df857529ef

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: I22a2ddd016dcc43c00b2b3d6be5d18921bf26d67
Patch-Set: 3