nfsd: fix delay timer on 32-bit architectures

The nfsd4_cb_layout_done() function takes a 'time_t' value,
multiplied by NSEC_PER_SEC*2 to get a nanosecond value.

This works fine on 64-bit architectures, but on 32-bit, any
value over 1 second results in a signed integer overflow
with unexpected results.

Cast one input to a 64-bit type in order to produce the
same result that we have on 64-bit architectures, regarless
of the type of nfsd4_lease.

Fixes: 6b9b2107 ("nfsd: give up on CB_LAYOUTRECALLs after two lease periods")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4layouts.c

@@ -675,7 +675,7 @@ nfsd4_cb_layout_done(struct nfsd4_callback *cb, struct rpc_task *task)
 
 		/* Client gets 2 lease periods to return it */
 		cutoff = ktime_add_ns(task->tk_start,
-					 nn->nfsd4_lease * NSEC_PER_SEC * 2);
+					 (u64)nn->nfsd4_lease * NSEC_PER_SEC * 2);
 
 		if (ktime_before(now, cutoff)) {
 			rpc_delay(task, HZ/100); /* 10 mili-seconds */