nfsd4: remove state lock from nfs4_state_shutdown

Protection of __nfs4_state_shutdown() with nfs4_lock_state() looks redundant.

This function is called by the last NFSd thread on it's exit and state lock
protects actually two functions (del_recall_lru is protected by recall_lock):
1) nfsd4_client_tracking_exit
2) __nfs4_state_shutdown_net

"nfsd4_client_tracking_exit" doesn't require state lock protection, because it's
state can be modified only by tracker callbacks.
Here a re they:
1) create: is called only from nfsd4_proc_compound.
2) remove: is called from either nfsd4_proc_compound or nfs4_laundromat.
3) check: is called only from nfsd4_proc_compound.
4) grace_done; called only from nfs4_laundromat.

nfsd4_proc_compound is called onll by NFSd kthread, which is exiting right
now.
nfs4_laundromat is called by laundry_wq. But laundromat_work was canceled
already.

"__nfs4_state_shutdown_net" also doesn't require state lock protection,
because all NFSd kthreads are dead, and no race can happen with NFSd start,
because "nfsd_up" flag is still set.
Moreover, all Nfsd shutdown is protected with global nfsd_mutex.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 41d2aed8ed061b542c4188fb9e21877a5a9ec0a0..ffec73cdfacae108c6a56b3c886d6b0acde96eae 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4930,9 +4930,7 @@ nfs4_state_shutdown(void)
        cancel_delayed_work_sync(&nn->laundromat_work);
        destroy_workqueue(laundry_wq);
        locks_end_grace(&nn->nfsd4_manager);
-       nfs4_lock_state();
        __nfs4_state_shutdown(net);
-       nfs4_unlock_state();
        nfsd4_destroy_callback_queue();
 }