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>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/lockd/bind.h b/include/linux/lockd/bind.h
index 246de1d84a2..6f1637c61e1 100644
--- a/include/linux/lockd/bind.h
+++ b/include/linux/lockd/bind.h
@@ -27,6 +27,7 @@ struct nlmsvc_binding {
                                                 struct nfs_fh *,
                                                 struct file **);
         void                    (*fclose)(struct file *);
+        unsigned long           (*get_grace_period)(void);
 };
 
 extern struct nlmsvc_binding *  nlmsvc_ops;
@@ -38,4 +39,12 @@ extern int	nlmclnt_proc(struct inode *, int, struct file_lock *);
 extern int      lockd_up(int proto);
 extern void     lockd_down(void);
 
+unsigned long get_nfs_grace_period(void);
+
+#ifdef CONFIG_NFSD_V4
+unsigned long get_nfs4_grace_period(void);
+#else
+static inline unsigned long get_nfs4_grace_period(void) {return 0;}
+#endif
+
 #endif /* LINUX_LOCKD_BIND_H */