nfsd4: document lease/grace-period limits
The current documentation here is out of date, and not quite right.
(Future work: some user documentation would be useful.)
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 7ab70ff..413cb8e 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1208,9 +1208,6 @@
#ifdef CONFIG_NFSD_V4
static ssize_t __nfsd4_write_time(struct file *file, char *buf, size_t size, time_t *time)
{
- /* if size > 10 seconds, call
- * nfs4_reset_lease() then write out the new lease (seconds) as reply
- */
char *mesg = buf;
int rv, i;
@@ -1220,6 +1217,18 @@
rv = get_int(&mesg, &i);
if (rv)
return rv;
+ /*
+ * Some sanity checking. We don't have a reason for
+ * these particular numbers, but problems with the
+ * extremes are:
+ * - Too short: the briefest network outage may
+ * cause clients to lose all their locks. Also,
+ * the frequent polling may be wasteful.
+ * - Too long: do you really want reboot recovery
+ * to take more than an hour? Or to make other
+ * clients wait an hour before being able to
+ * revoke a dead client's locks?
+ */
if (i < 10 || i > 3600)
return -EINVAL;
*time = i;