staging/lustre/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 <[email protected]>
Reviewed-on: http://review.whamcloud.com/9881
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4558
Reviewed-by: Bobi Jam <[email protected]>
Reviewed-by: Lai Siyao <[email protected]>
Signed-off-by: Oleg Drokin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions