knfsd: lockd: nfsd4: use same grace period for lockd and nfsd4

Both lockd and (in the nfsv4 case) nfsd enforce a "grace period" after reboot,
during which clients may reclaim locks from the previous server instance, but
may not acquire new locks.

Currently the lockd and nfsd enforce grace periods of different lengths.  This
may cause problems when we reboot a server with both v2/v3 and v4 clients.
For example, if the lockd grace period is shorter (as is likely the case),
then a v3 client might acquire a new lock that conflicts with a lock already
held (but not yet reclaimed) by a v4 client.

This patch calculates a lease time that lockd and nfsd can both use.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 13 insertions, 4 deletions

diff --git a/fs/nfsd/lockd.c b/fs/nfsd/lockd.c
index 221acd1f11f6..9e4a568a5013 100644
--- a/fs/nfsd/lockd.c
+++ b/fs/nfsd/lockd.c
@@ -65,6 +65,7 @@ nlm_fclose(struct file *filp)
 static struct nlmsvc_binding	nfsd_nlm_ops = {
 	.fopen		= nlm_fopen,		/* open file for locking */
 	.fclose		= nlm_fclose,		/* close file */
+	.get_grace_period = get_nfs4_grace_period,
 };
 
 void
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8c52913d7cb6..9cc31eaf3857 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -51,6 +51,7 @@
 #include <linux/namei.h>
 #include <linux/mutex.h>
 #include <linux/lockd/bind.h>
+#include <linux/module.h>
 
 #define NFSDDBG_FACILITY                NFSDDBG_PROC
 
@@ -3190,20 +3191,27 @@ nfsd4_load_reboot_recovery_data(void)
 		printk("NFSD: Failure reading reboot recovery data\n");
 }
 
+unsigned long
+get_nfs4_grace_period(void)
+{
+	return max(user_lease_time, lease_time) * HZ;
+}
+
 /* initialization to perform when the nfsd service is started: */
 
 static void
 __nfs4_state_start(void)
 {
-	time_t grace_time;
+	unsigned long grace_time;
 
 	boot_time = get_seconds();
-	grace_time = max(user_lease_time, lease_time);
+	grace_time = get_nfs_grace_period();
 	lease_time = user_lease_time;
 	in_grace = 1;
-	printk("NFSD: starting %ld-second grace period\n", grace_time);
+	printk(KERN_INFO "NFSD: starting %ld-second grace period\n",
+	       grace_time/HZ);
 	laundry_wq = create_singlethread_workqueue("nfsd4");
-	queue_delayed_work(laundry_wq, &laundromat_work, grace_time*HZ);
+	queue_delayed_work(laundry_wq, &laundromat_work, grace_time);
 }
 
 int