ubifs: tnc: use monotonic znode timestamp

The tnc uses get_seconds() based timestamps to check the age of a znode,
which has two problems: on 32-bit architectures this may overflow in
2038 or 2106, and it gives incorrect information when the system time
is updated using settimeofday().

Using montonic timestamps with ktime_get_seconds() solves both thes
problems.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/shrinker.c

@@ -71,7 +71,7 @@ static int shrink_tnc(struct ubifs_info *c, int nr, int age, int *contention)
 {
 	int total_freed = 0;
 	struct ubifs_znode *znode, *zprev;
-	int time = get_seconds();
+	time64_t time = ktime_get_seconds();
 
 	ubifs_assert(mutex_is_locked(&c->umount_mutex));
 	ubifs_assert(mutex_is_locked(&c->tnc_mutex));

fs/ubifs/tnc.c

@@ -1179,7 +1179,7 @@ int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
 {
 	int err, exact;
 	struct ubifs_znode *znode;
-	unsigned long time = get_seconds();
+	time64_t time = ktime_get_seconds();
 
 	dbg_tnck(key, "search key ");
 	ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
@@ -1315,7 +1315,7 @@ static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
 {
 	int err, exact;
 	struct ubifs_znode *znode;
-	unsigned long time = get_seconds();
+	time64_t time = ktime_get_seconds();
 
 	dbg_tnck(key, "search and dirty key ");
 

fs/ubifs/tnc_misc.c

@@ -435,7 +435,7 @@ struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
 
 	zbr->znode = znode;
 	znode->parent = parent;
-	znode->time = get_seconds();
+	znode->time = ktime_get_seconds();
 	znode->iip = iip;
 
 	return znode;

fs/ubifs/ubifs.h

@@ -758,7 +758,7 @@ struct ubifs_znode {
 	struct ubifs_znode *parent;
 	struct ubifs_znode *cnext;
 	unsigned long flags;
-	unsigned long time;
+	time64_t time;
 	int level;
 	int child_cnt;
 	int iip;