lockd: stop abusing file_lock_list

Currently lockd directly access the file_lock_list from fs/locks.c.
It does so to mark locks granted or reclaimable.  This is very
suboptimal, because a) lockd needs to poke into locks.c internals, and
b) it needs to iterate over all locks in the system for marking locks
granted or reclaimable.

This patch adds lists for granted and reclaimable locks to the nlm_host
structure instead, and adds locks to those.

nlmclnt_lock:
	now adds the lock to h_granted instead of setting the
	NFS_LCK_GRANTED, still O(1)

nlmclnt_mark_reclaim:
	goes away completely, replaced by a list_splice_init.
	Complexity reduced from O(locks in the system) to O(1)

reclaimer:
	iterates over h_reclaim now, complexity reduced from
	O(locks in the system) to O(locks per nlm_host)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 80ae3127699f..cb469431bd1d 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -465,7 +465,6 @@ static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *ho
 {
         BUG_ON(fl->fl_ops != NULL);
         fl->fl_u.nfs_fl.state = 0;
-        fl->fl_u.nfs_fl.flags = 0;
         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
         fl->fl_ops = &nlmclnt_lock_ops;
 }
@@ -552,8 +551,8 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 
         if (resp->status == NLM_LCK_GRANTED) {
                 fl->fl_u.nfs_fl.state = host->h_state;
-                fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
                 fl->fl_flags |= FL_SLEEP;
+                list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
                 do_vfs_lock(fl);
         }
         status = nlm_stat_to_errno(resp->status);
@@ -619,9 +618,11 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
         struct nlm_res  *resp = &req->a_res;
         int             status;
 
-        /* Clean the GRANTED flag now so the lock doesn't get
-         * reclaimed while we're stuck in the unlock call. */
-        fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
+        /*
+         * Remove from the granted list now so the lock doesn't get
+         * reclaimed while we're stuck in the unlock call.
+         */
+        list_del(&fl->fl_u.nfs_fl.list);
 
         /*
          * Note: the server is supposed to either grant us the unlock