f2fs: skip releasing nodes in chindless extent tree

If there are no nodes in extent tree, let's skip releasing step to avoid
any overhead of grabbing/releasing extent tree lock.

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

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 9febbc622bf53103bca9eff0fe27d21aa7b26ed3..ccd5c636d3fe026d0c5379d4062ee204fc7faa17 100644 (file)
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -570,9 +570,11 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
 
        /* 1. remove unreferenced extent tree */
        list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
-               write_lock(&et->lock);
-               node_cnt += __free_extent_tree(sbi, et, true);
-               write_unlock(&et->lock);
+               if (atomic_read(&et->node_cnt)) {
+                       write_lock(&et->lock);
+                       node_cnt += __free_extent_tree(sbi, et, true);
+                       write_unlock(&et->lock);
+               }
 
                list_del_init(&et->list);
                radix_tree_delete(&sbi->extent_tree_root, et->ino);
@@ -618,6 +620,9 @@ free_node:
                for (i = 0; i < found; i++) {
                        struct extent_tree *et = treevec[i];
 
+                       if (!atomic_read(&et->node_cnt))
+                               continue;
+
                        if (write_trylock(&et->lock)) {
                                node_cnt += __free_extent_tree(sbi, et, false);
                                write_unlock(&et->lock);
@@ -641,7 +646,7 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode)
        struct extent_tree *et = F2FS_I(inode)->extent_tree;
        unsigned int node_cnt = 0;
 
-       if (!et)
+       if (!et || !atomic_read(&et->node_cnt))
                return 0;
 
        write_lock(&et->lock);