quota: reclaim least recently used dquots

The dquots in the free_dquots list are not reclaimed in LRU way.
put_dquot_last() puts entries to the tail and dqcache_shrink_scan()
frees from the tail. Free unreferenced dquots in LRU order because it
seems more reasonable than freeing most recently used.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index d88231e..241b00f 100644 (file)
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -716,7 +716,7 @@ dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
        unsigned long freed = 0;
 
        spin_lock(&dq_list_lock);
-       head = free_dquots.prev;
+       head = free_dquots.next;
        while (head != &free_dquots && sc->nr_to_scan) {
                dquot = list_entry(head, struct dquot, dq_free);
                remove_dquot_hash(dquot);
@@ -725,7 +725,7 @@ dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
                do_destroy_dquot(dquot);
                sc->nr_to_scan--;
                freed++;
-               head = free_dquots.prev;
+               head = free_dquots.next;
        }
        spin_unlock(&dq_list_lock);
        return freed;