locks: allow __break_lease to sleep even when break_time is 0

A fl->fl_break_time of 0 has a special meaning to the lease break code that basically means "never break the lease". knfsd uses this to ensure that leases don't disappear out from under it. Unfortunately, the code in __break_lease can end up passing this value to wait_event_interruptible as a timeout, which prevents it from going to sleep at all. This makes __break_lease to spin in a tight loop and causes soft lockups. Fix this by ensuring that we pass a minimum value of 1 as a timeout instead. Cc: <[email protected]> Cc: J. Bruce Fields <[email protected]> Reported-by: Terry Barnaby <[email protected]> Signed-off-by: Jeff Layton <[email protected]>
rtvt123 · Apr 15, 2014 · f1c6bb2 · f1c6bb2
1 parent 55101e2
commit f1c6bb2
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/fs/locks.c b/fs/locks.c
@@ -1391,11 +1391,10 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 
 restart:
 	break_time = flock->fl_break_time;
-	if (break_time != 0) {
+	if (break_time != 0)
 		break_time -= jiffies;
-		if (break_time == 0)
-			break_time++;
-	}
+	if (break_time == 0)
+		break_time++;
 	locks_insert_block(flock, new_fl);
 	spin_unlock(&inode->i_lock);
 	error = wait_event_interruptible_timeout(new_fl->fl_wait,