f2fs: use atomic variable for total_extent_tree

It would be better to use atomic variable for total_extent_tree.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/debug.c

@@ -38,7 +38,7 @@ static void update_general_status(struct f2fs_sb_info *sbi)
 	si->hit_rbtree = atomic64_read(&sbi->read_hit_rbtree);
 	si->hit_total = si->hit_largest + si->hit_cached + si->hit_rbtree;
 	si->total_ext = atomic64_read(&sbi->total_hit_ext);
-	si->ext_tree = sbi->total_ext_tree;
+	si->ext_tree = atomic_read(&sbi->total_ext_tree);
 	si->ext_node = atomic_read(&sbi->total_ext_node);
 	si->ndirty_node = get_pages(sbi, F2FS_DIRTY_NODES);
 	si->ndirty_dent = get_pages(sbi, F2FS_DIRTY_DENTS);
@@ -193,7 +193,8 @@ get_cache:
 	si->cache_mem += si->inmem_pages * sizeof(struct inmem_pages);
 	for (i = 0; i <= UPDATE_INO; i++)
 		si->cache_mem += sbi->im[i].ino_num * sizeof(struct ino_entry);
-	si->cache_mem += sbi->total_ext_tree * sizeof(struct extent_tree);
+	si->cache_mem += atomic_read(&sbi->total_ext_tree) *
+						sizeof(struct extent_tree);
 	si->cache_mem += atomic_read(&sbi->total_ext_node) *
 						sizeof(struct extent_node);
 

fs/f2fs/extent_cache.c

@@ -70,7 +70,7 @@ static struct extent_tree *__grab_extent_tree(struct inode *inode)
 		rwlock_init(&et->lock);
 		atomic_set(&et->refcount, 0);
 		et->count = 0;
-		sbi->total_ext_tree++;
+		atomic_inc(&sbi->total_ext_tree);
 	}
 	atomic_inc(&et->refcount);
 	up_write(&sbi->extent_tree_lock);
@@ -570,7 +570,7 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
 
 				radix_tree_delete(root, et->ino);
 				kmem_cache_free(extent_tree_slab, et);
-				sbi->total_ext_tree--;
+				atomic_dec(&sbi->total_ext_tree);
 				tree_cnt++;
 
 				if (node_cnt + tree_cnt >= nr_shrink)
@@ -663,7 +663,7 @@ void f2fs_destroy_extent_tree(struct inode *inode)
 	f2fs_bug_on(sbi, atomic_read(&et->refcount) || et->count);
 	radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
 	kmem_cache_free(extent_tree_slab, et);
-	sbi->total_ext_tree--;
+	atomic_dec(&sbi->total_ext_tree);
 	up_write(&sbi->extent_tree_lock);
 
 	F2FS_I(inode)->extent_tree = NULL;
@@ -715,7 +715,7 @@ void init_extent_cache_info(struct f2fs_sb_info *sbi)
 	init_rwsem(&sbi->extent_tree_lock);
 	INIT_LIST_HEAD(&sbi->extent_list);
 	spin_lock_init(&sbi->extent_lock);
-	sbi->total_ext_tree = 0;
+	atomic_set(&sbi->total_ext_tree, 0);
 	atomic_set(&sbi->total_ext_node, 0);
 }
 

fs/f2fs/f2fs.h

@@ -762,7 +762,7 @@ struct f2fs_sb_info {
 	struct rw_semaphore extent_tree_lock;	/* locking extent radix tree */
 	struct list_head extent_list;		/* lru list for shrinker */
 	spinlock_t extent_lock;			/* locking extent lru list */
-	int total_ext_tree;			/* extent tree count */
+	atomic_t total_ext_tree;		/* extent tree count */
 	atomic_t total_ext_node;		/* extent info count */
 
 	/* basic filesystem units */

fs/f2fs/node.c

@@ -65,7 +65,8 @@ bool available_free_memory(struct f2fs_sb_info *sbi, int type)
 				sizeof(struct ino_entry)) >> PAGE_CACHE_SHIFT;
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
 	} else if (type == EXTENT_CACHE) {
-		mem_size = (sbi->total_ext_tree * sizeof(struct extent_tree) +
+		mem_size = (atomic_read(&sbi->total_ext_tree) *
+				sizeof(struct extent_tree) +
 				atomic_read(&sbi->total_ext_node) *
 				sizeof(struct extent_node)) >> PAGE_CACHE_SHIFT;
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);

fs/f2fs/shrinker.c

@@ -32,7 +32,8 @@ static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
 
 static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
 {
-	return sbi->total_ext_tree + atomic_read(&sbi->total_ext_node);
+	return atomic_read(&sbi->total_ext_tree) +
+				atomic_read(&sbi->total_ext_node);
 }
 
 unsigned long f2fs_shrink_count(struct shrinker *shrink,