[PATCH] knfsd: nfsd4: grace period end

For the purposes of reboot recovery, we want to do some work during the
transition period at the end of the grace period.  Some of that work must be
guaranteed to have a certain relationship with the end of the grace period, so
we want to control the transition there.

Our approach is to modify the in_grace() checks to consult a global variable
instead of checking the time directly, to schedule the first run of the
laundromat thread at the end of the grace period, and to set the global
end-of-grace-period there.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfs4state.c

@@ -55,7 +55,7 @@
 static time_t lease_time = 90;     /* default lease time */
 static time_t user_lease_time = 90;
 time_t boot_time;
-static time_t grace_end = 0;
+static int in_grace = 1;
 static u32 current_clientid = 1;
 static u32 current_ownerid = 1;
 static u32 current_fileid = 1;
@@ -1908,6 +1908,13 @@ nfsd4_renew(clientid_t *clid)
 	return status;
 }
 
+static void
+end_grace(void)
+{
+	dprintk("NFSD: end of grace period\n");
+	in_grace = 0;
+}
+
 time_t
 nfs4_laundromat(void)
 {
@@ -1922,6 +1929,8 @@ nfs4_laundromat(void)
 	nfs4_lock_state();
 
 	dprintk("NFSD: laundromat service - starting\n");
+	if (in_grace)
+		end_grace();
 	list_for_each_safe(pos, next, &client_lru) {
 		clp = list_entry(pos, struct nfs4_client, cl_lru);
 		if (time_after((unsigned long)clp->cl_time, (unsigned long)cutoff)) {
@@ -3223,10 +3232,10 @@ __nfs4_state_start(void)
 	boot_time = get_seconds();
 	grace_time = max(user_lease_time, lease_time);
 	lease_time = user_lease_time;
+	in_grace = 1;
 	printk("NFSD: starting %ld-second grace period\n", grace_time);
-	grace_end = boot_time + grace_time;
 	laundry_wq = create_singlethread_workqueue("nfsd4");
-	queue_delayed_work(laundry_wq, &laundromat_work, NFSD_LEASE_TIME*HZ);
+	queue_delayed_work(laundry_wq, &laundromat_work, grace_time*HZ);
 }
 
 int
@@ -3247,14 +3256,7 @@ nfs4_state_start(void)
 int
 nfs4_in_grace(void)
 {
-	return get_seconds() < grace_end;
-}
-
-void
-set_no_grace(void)
-{
-	printk("NFSD: ERROR in reboot recovery.  State reclaims will fail.\n");
-	grace_end = get_seconds();
+	return in_grace;
 }
 
 time_t