Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs pile 4 from Al Viro:
 "list_lru pile, mostly"

This came out of Andrew's pile, Al ended up doing the merge work so that
Andrew didn't have to.

Additionally, a few fixes.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (42 commits)
  super: fix for destroy lrus
  list_lru: dynamically adjust node arrays
  shrinker: Kill old ->shrink API.
  shrinker: convert remaining shrinkers to count/scan API
  staging/lustre/libcfs: cleanup linux-mem.h
  staging/lustre/ptlrpc: convert to new shrinker API
  staging/lustre/obdclass: convert lu_object shrinker to count/scan API
  staging/lustre/ldlm: convert to shrinkers to count/scan API
  hugepage: convert huge zero page shrinker to new shrinker API
  i915: bail out earlier when shrinker cannot acquire mutex
  drivers: convert shrinkers to new count/scan API
  fs: convert fs shrinkers to new scan/count API
  xfs: fix dquot isolation hang
  xfs-convert-dquot-cache-lru-to-list_lru-fix
  xfs: convert dquot cache lru to list_lru
  xfs: rework buffer dispose list tracking
  xfs-convert-buftarg-lru-to-generic-code-fix
  xfs: convert buftarg LRU to generic code
  fs: convert inode and dentry shrinking to be node aware
  vmscan: per-node deferred work
  ...

drivers/md/bcache/btree.c

@@ -597,24 +597,19 @@ static int mca_reap(struct btree *b, struct closure *cl, unsigned min_order)
 	return 0;
 }
 
-static int bch_mca_shrink(struct shrinker *shrink, struct shrink_control *sc)
+static unsigned long bch_mca_scan(struct shrinker *shrink,
+				  struct shrink_control *sc)
 {
 	struct cache_set *c = container_of(shrink, struct cache_set, shrink);
 	struct btree *b, *t;
 	unsigned long i, nr = sc->nr_to_scan;
+	unsigned long freed = 0;
 
 	if (c->shrinker_disabled)
-		return 0;
+		return SHRINK_STOP;
 
 	if (c->try_harder)
-		return 0;
-
-	/*
-	 * If nr == 0, we're supposed to return the number of items we have
-	 * cached. Not allowed to return -1.
-	 */
-	if (!nr)
-		return mca_can_free(c) * c->btree_pages;
+		return SHRINK_STOP;
 
 	/* Return -1 if we can't do anything right now */
 	if (sc->gfp_mask & __GFP_WAIT)
@@ -634,14 +629,14 @@ static int bch_mca_shrink(struct shrinker *shrink, struct shrink_control *sc)
 
 	i = 0;
 	list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) {
-		if (!nr)
+		if (freed >= nr)
 			break;
 
 		if (++i > 3 &&
 		    !mca_reap(b, NULL, 0)) {
 			mca_data_free(b);
 			rw_unlock(true, b);
-			--nr;
+			freed++;
 		}
 	}
 
@@ -652,7 +647,7 @@ static int bch_mca_shrink(struct shrinker *shrink, struct shrink_control *sc)
 	if (list_empty(&c->btree_cache))
 		goto out;
 
-	for (i = 0; nr && i < c->bucket_cache_used; i++) {
+	for (i = 0; (nr--) && i < c->bucket_cache_used; i++) {
 		b = list_first_entry(&c->btree_cache, struct btree, list);
 		list_rotate_left(&c->btree_cache);
 
@@ -661,14 +656,27 @@ static int bch_mca_shrink(struct shrinker *shrink, struct shrink_control *sc)
 			mca_bucket_free(b);
 			mca_data_free(b);
 			rw_unlock(true, b);
-			--nr;
+			freed++;
 		} else
 			b->accessed = 0;
 	}
 out:
-	nr = mca_can_free(c) * c->btree_pages;
 	mutex_unlock(&c->bucket_lock);
-	return nr;
+	return freed;
+}
+
+static unsigned long bch_mca_count(struct shrinker *shrink,
+				   struct shrink_control *sc)
+{
+	struct cache_set *c = container_of(shrink, struct cache_set, shrink);
+
+	if (c->shrinker_disabled)
+		return 0;
+
+	if (c->try_harder)
+		return 0;
+
+	return mca_can_free(c) * c->btree_pages;
 }
 
 void bch_btree_cache_free(struct cache_set *c)
@@ -737,7 +745,8 @@ int bch_btree_cache_alloc(struct cache_set *c)
 		c->verify_data = NULL;
 #endif
 
-	c->shrink.shrink = bch_mca_shrink;
+	c->shrink.count_objects = bch_mca_count;
+	c->shrink.scan_objects = bch_mca_scan;
 	c->shrink.seeks = 4;
 	c->shrink.batch = c->btree_pages * 2;
 	register_shrinker(&c->shrink);

drivers/md/bcache/sysfs.c

@@ -556,7 +556,7 @@ STORE(__bch_cache_set)
 		struct shrink_control sc;
 		sc.gfp_mask = GFP_KERNEL;
 		sc.nr_to_scan = strtoul_or_return(buf);
-		c->shrink.shrink(&c->shrink, &sc);
+		c->shrink.scan_objects(&c->shrink, &sc);
 	}
 
 	sysfs_strtoul(congested_read_threshold_us,

drivers/md/dm-bufio.c

@@ -1425,62 +1425,75 @@ static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp,
 				unsigned long max_jiffies)
 {
 	if (jiffies - b->last_accessed < max_jiffies)
-		return 1;
+		return 0;
 
 	if (!(gfp & __GFP_IO)) {
 		if (test_bit(B_READING, &b->state) ||
 		    test_bit(B_WRITING, &b->state) ||
 		    test_bit(B_DIRTY, &b->state))
-			return 1;
+			return 0;
 	}
 
 	if (b->hold_count)
-		return 1;
+		return 0;
 
 	__make_buffer_clean(b);
 	__unlink_buffer(b);
 	__free_buffer_wake(b);
 
-	return 0;
+	return 1;
 }
 
-static void __scan(struct dm_bufio_client *c, unsigned long nr_to_scan,
-		   struct shrink_control *sc)
+static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan,
+		   gfp_t gfp_mask)
 {
 	int l;
 	struct dm_buffer *b, *tmp;
+	long freed = 0;
 
 	for (l = 0; l < LIST_SIZE; l++) {
-		list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list)
-			if (!__cleanup_old_buffer(b, sc->gfp_mask, 0) &&
-			    !--nr_to_scan)
-				return;
+		list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) {
+			freed += __cleanup_old_buffer(b, gfp_mask, 0);
+			if (!--nr_to_scan)
+				break;
+		}
 		dm_bufio_cond_resched();
 	}
+	return freed;
 }
 
-static int shrink(struct shrinker *shrinker, struct shrink_control *sc)
+static unsigned long
+dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 {
-	struct dm_bufio_client *c =
-	    container_of(shrinker, struct dm_bufio_client, shrinker);
-	unsigned long r;
-	unsigned long nr_to_scan = sc->nr_to_scan;
+	struct dm_bufio_client *c;
+	unsigned long freed;
 
+	c = container_of(shrink, struct dm_bufio_client, shrinker);
 	if (sc->gfp_mask & __GFP_IO)
 		dm_bufio_lock(c);
 	else if (!dm_bufio_trylock(c))
-		return !nr_to_scan ? 0 : -1;
-
-	if (nr_to_scan)
-		__scan(c, nr_to_scan, sc);
-
-	r = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY];
-	if (r > INT_MAX)
-		r = INT_MAX;
+		return SHRINK_STOP;
 
+	freed  = __scan(c, sc->nr_to_scan, sc->gfp_mask);
 	dm_bufio_unlock(c);
+	return freed;
+}
 
-	return r;
+static unsigned long
+dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
+{
+	struct dm_bufio_client *c;
+	unsigned long count;
+
+	c = container_of(shrink, struct dm_bufio_client, shrinker);
+	if (sc->gfp_mask & __GFP_IO)
+		dm_bufio_lock(c);
+	else if (!dm_bufio_trylock(c))
+		return 0;
+
+	count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY];
+	dm_bufio_unlock(c);
+	return count;
 }
 
 /*
@@ -1582,7 +1595,8 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
 	__cache_size_refresh();
 	mutex_unlock(&dm_bufio_clients_lock);
 
-	c->shrinker.shrink = shrink;
+	c->shrinker.count_objects = dm_bufio_shrink_count;
+	c->shrinker.scan_objects = dm_bufio_shrink_scan;
 	c->shrinker.seeks = 1;
 	c->shrinker.batch = 0;
 	register_shrinker(&c->shrinker);
@@ -1669,7 +1683,7 @@ static void cleanup_old_buffers(void)
 			struct dm_buffer *b;
 			b = list_entry(c->lru[LIST_CLEAN].prev,
 				       struct dm_buffer, lru_list);
-			if (__cleanup_old_buffer(b, 0, max_age * HZ))
+			if (!__cleanup_old_buffer(b, 0, max_age * HZ))
 				break;
 			dm_bufio_cond_resched();
 		}