nfsd4: remove state lock from nfs4_state_shutdown
authorStanislav Kinsbursky <skinsbursky@parallels.com>
Wed, 21 Nov 2012 15:07:38 +0000 (18:07 +0300)
committerJ. Bruce Fields <bfields@redhat.com>
Wed, 28 Nov 2012 15:13:49 +0000 (10:13 -0500)
commitec28e02ca5f2a4287c19c585f8be2d9b3ba123ea
tree3813dba8716d0d7ab285c82f51c98599662d3f1b
parentdba88ba55a06ff8bef467f2ca3f7904aeab8762a
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>
fs/nfsd/nfs4state.c