f2fs: use atomic type for node count in extent tree

1. rename field in struct extent_tree from count to node_cnt for
   readability.
2. alter to use atomic type for node_cnt.

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

1 files changed, 9 insertions, 8 deletions

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 4dee2be9a648..9febbc622bf5 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -36,7 +36,7 @@ static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
 
         rb_link_node(&en->rb_node, parent, p);
         rb_insert_color(&en->rb_node, &et->root);
-        et->count++;
+        atomic_inc(&et->node_cnt);
         atomic_inc(&sbi->total_ext_node);
         return en;
 }
@@ -45,7 +45,7 @@ static void __detach_extent_node(struct f2fs_sb_info *sbi,
                                 struct extent_tree *et, struct extent_node *en)
 {
         rb_erase(&en->rb_node, &et->root);
-        et->count--;
+        atomic_dec(&et->node_cnt);
         atomic_dec(&sbi->total_ext_node);
 
         if (et->cached_en == en)
@@ -69,7 +69,7 @@ static struct extent_tree *__grab_extent_tree(struct inode *inode)
                 et->cached_en = NULL;
                 rwlock_init(&et->lock);
                 INIT_LIST_HEAD(&et->list);
-                et->count = 0;
+                atomic_set(&et->node_cnt, 0);
                 atomic_inc(&sbi->total_ext_tree);
         } else {
                 atomic_dec(&sbi->total_zombie_tree);
@@ -133,7 +133,7 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
 {
         struct rb_node *node, *next;
         struct extent_node *en;
-        unsigned int count = et->count;
+        unsigned int count = atomic_read(&et->node_cnt);
 
         node = rb_first(&et->root);
         while (node) {
@@ -154,7 +154,7 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
                 node = next;
         }
 
-        return count - et->count;
+        return count - atomic_read(&et->node_cnt);
 }
 
 static void __drop_largest_extent(struct inode *inode,
@@ -192,7 +192,7 @@ bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
                 le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
 
         write_lock(&et->lock);
-        if (et->count)
+        if (atomic_read(&et->node_cnt))
                 goto out;
 
         en = __init_extent_tree(sbi, et, &ei);
@@ -660,7 +660,8 @@ void f2fs_destroy_extent_tree(struct inode *inode)
         if (!et)
                 return;
 
-        if (inode->i_nlink && !is_bad_inode(inode) && et->count) {
+        if (inode->i_nlink && !is_bad_inode(inode) &&
+                                        atomic_read(&et->node_cnt)) {
                 down_write(&sbi->extent_tree_lock);
                 list_add_tail(&et->list, &sbi->zombie_list);
                 atomic_inc(&sbi->total_zombie_tree);
@@ -673,7 +674,7 @@ void f2fs_destroy_extent_tree(struct inode *inode)
 
         /* delete extent tree entry in radix tree */
         down_write(&sbi->extent_tree_lock);
-        f2fs_bug_on(sbi, et->count);
+        f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
         radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
         kmem_cache_free(extent_tree_slab, et);
         atomic_dec(&sbi->total_ext_tree);