1 files changed, 28 insertions, 26 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 9a702e19353..7f30bdc57d1 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -528,7 +528,7 @@ restart:
 		if (atomic_read(&dquot->dq_count)) {
 			DEFINE_WAIT(wait);
 
-			atomic_inc(&dquot->dq_count);
+			dqgrab(dquot);
 			prepare_to_wait(&dquot->dq_wait_unused, &wait,
 					TASK_UNINTERRUPTIBLE);
 			spin_unlock(&dq_list_lock);
@@ -581,9 +581,17 @@ int dquot_scan_active(struct super_block *sb,
 		dqstats_inc(DQST_LOOKUPS);
 		dqput(old_dquot);
 		old_dquot = dquot;
-		ret = fn(dquot, priv);
-		if (ret < 0)
-			goto out;
+		/*
+		 * ->release_dquot() can be racing with us. Our reference
+		 * protects us from new calls to it so just wait for any
+		 * outstanding call and recheck the DQ_ACTIVE_B after that.
+		 */
+		wait_on_dquot(dquot);
+		if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
+			ret = fn(dquot, priv);
+			if (ret < 0)
+				goto out;
+		}
 		spin_lock(&dq_list_lock);
 		/* We are safe to continue now because our dquot could not
 		 * be moved out of the inuse list while we hold the reference */
@@ -624,7 +632,7 @@ int dquot_writeback_dquots(struct super_block *sb, int type)
 			/* Now we have active dquot from which someone is
  			 * holding reference so we can safely just increase
 			 * use count */
-			atomic_inc(&dquot->dq_count);
+			dqgrab(dquot);
 			spin_unlock(&dq_list_lock);
 			dqstats_inc(DQST_LOOKUPS);
 			err = sb->dq_op->write_dquot(dquot);
@@ -687,45 +695,39 @@ int dquot_quota_sync(struct super_block *sb, int type)
 }
 EXPORT_SYMBOL(dquot_quota_sync);
 
-/* Free unused dquots from cache */
-static void prune_dqcache(int count)
+static unsigned long
+dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 {
 	struct list_head *head;
 	struct dquot *dquot;
+	unsigned long freed = 0;
 
+	spin_lock(&dq_list_lock);
 	head = free_dquots.prev;
-	while (head != &free_dquots && count) {
+	while (head != &free_dquots && sc->nr_to_scan) {
 		dquot = list_entry(head, struct dquot, dq_free);
 		remove_dquot_hash(dquot);
 		remove_free_dquot(dquot);
 		remove_inuse(dquot);
 		do_destroy_dquot(dquot);
-		count--;
+		sc->nr_to_scan--;
+		freed++;
 		head = free_dquots.prev;
 	}
+	spin_unlock(&dq_list_lock);
+	return freed;
 }
 
-/*
- * This is called from kswapd when we think we need some
- * more memory
- */
-static int shrink_dqcache_memory(struct shrinker *shrink,
-				 struct shrink_control *sc)
+static unsigned long
+dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 {
-	int nr = sc->nr_to_scan;
-
-	if (nr) {
-		spin_lock(&dq_list_lock);
-		prune_dqcache(nr);
-		spin_unlock(&dq_list_lock);
-	}
-	return ((unsigned)
-		percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS])
-		/100) * sysctl_vfs_cache_pressure;
+	return vfs_pressure_ratio(
+	percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
 }
 
 static struct shrinker dqcache_shrinker = {
-	.shrink = shrink_dqcache_memory,
+	.count_objects = dqcache_shrink_count,
+	.scan_objects = dqcache_shrink_scan,
 	.seeks = DEFAULT_SEEKS,
 };