f2fs: fix the debugfs entry creation path

As the "status" debugfs entry will be maintained for entire F2FS filesystem
irrespective of the number of partitions.
So, we can move the initialization to the init part of the f2fs and destroy will
be done from exit part. After making changes, for individual partition mount -
entry creation code will not be executed.

Signed-off-by: Jianpeng Ma <[e-mail]>
Signed-off-by: Namjae Jeon <[e-mail]>
Signed-off-by: Amit Sahrawat <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/debug.c

···
 	.release = single_release,
 };
 
-static int init_stats(struct f2fs_sb_info *sbi)
+int f2fs_build_stats(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
 	struct f2fs_stat_info *si;
···
 	return 0;
 }
 
-int f2fs_build_stats(struct f2fs_sb_info *sbi)
-{
-	int retval;
-
-	retval = init_stats(sbi);
-	if (retval)
-		return retval;
-
-	if (!debugfs_root)
-		debugfs_root = debugfs_create_dir("f2fs", NULL);
-
-	debugfs_create_file("status", S_IRUGO, debugfs_root, NULL, &stat_fops);
-	return 0;
-}
-
 void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_stat_info *si = sbi->stat_info;
···
 	kfree(sbi->stat_info);
 }
 
-void destroy_root_stats(void)
+void __init f2fs_create_root_stats(void)
+{
+	debugfs_root = debugfs_create_dir("f2fs", NULL);
+	if (debugfs_root)
+		debugfs_create_file("status", S_IRUGO, debugfs_root,
+					 NULL, &stat_fops);
+}
+
+void f2fs_destroy_root_stats(void)
 {
 	debugfs_remove_recursive(debugfs_root);
 	debugfs_root = NULL;

fs/f2fs/f2fs.h

···
 
 int f2fs_build_stats(struct f2fs_sb_info *);
 void f2fs_destroy_stats(struct f2fs_sb_info *);
-void destroy_root_stats(void);
+void f2fs_create_root_stats(void);
+void f2fs_destroy_root_stats(void);
 #else
 #define stat_inc_call_count(si)
 #define stat_inc_seg_count(si, type)
···
 
 static inline int f2fs_build_stats(struct f2fs_sb_info *sbi) { return 0; }
 static inline void f2fs_destroy_stats(struct f2fs_sb_info *sbi) { }
-static inline void destroy_root_stats(void) { }
+static inline void f2fs_create_root_stats(void) { }
+static inline void f2fs_destroy_root_stats(void) { }
 #endif
 
 extern const struct file_operations f2fs_dir_operations;

fs/f2fs/super.c

···
 	err = create_checkpoint_caches();
 	if (err)
 		goto fail;
-	return register_filesystem(&f2fs_fs_type);
+	err = register_filesystem(&f2fs_fs_type);
+	if (err)
+		goto fail;
+	f2fs_create_root_stats();
 fail:
 	return err;
 }
 
 static void __exit exit_f2fs_fs(void)
 {
-	destroy_root_stats();
+	f2fs_destroy_root_stats();
 	unregister_filesystem(&f2fs_fs_type);
 	destroy_checkpoint_caches();
 	destroy_gc_caches();