f2fs: monitor zombie_tree count

This patch adds an entry to show the number of zombie extent_tree.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/debug.c

@@ -39,6 +39,7 @@ static void update_general_status(struct f2fs_sb_info *sbi)
 	si->hit_total = si->hit_largest + si->hit_cached + si->hit_rbtree;
 	si->total_ext = atomic64_read(&sbi->total_hit_ext);
 	si->ext_tree = atomic_read(&sbi->total_ext_tree);
+	si->zombie_tree = atomic_read(&sbi->total_zombie_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);
@@ -292,8 +293,8 @@ static int stat_show(struct seq_file *s, void *v)
 				!si->total_ext ? 0 :
 				div64_u64(si->hit_total * 100, si->total_ext),
 				si->hit_total, si->total_ext);
-		seq_printf(s, "  - Inner Struct Count: tree: %d, node: %d\n",
-				si->ext_tree, si->ext_node);
+		seq_printf(s, "  - Inner Struct Count: tree: %d(%d), node: %d\n",
+				si->ext_tree, si->zombie_tree, si->ext_node);
 		seq_puts(s, "\nBalancing F2FS Async:\n");
 		seq_printf(s, "  - inmem: %4d, wb: %4d\n",
 			   si->inmem_pages, si->wb_pages);

fs/f2fs/f2fs.h

@@ -1890,7 +1890,7 @@ struct f2fs_stat_info {
 	int main_area_segs, main_area_sections, main_area_zones;
 	unsigned long long hit_largest, hit_cached, hit_rbtree;
 	unsigned long long hit_total, total_ext;
-	int ext_tree, ext_node;
+	int ext_tree, zombie_tree, ext_node;
 	int ndirty_node, ndirty_meta;
 	int ndirty_dent, ndirty_dirs, ndirty_data, ndirty_files;
 	int nats, dirty_nats, sits, dirty_sits, fnids;