f2fs: build stat_info before orphan inode recovery

f2fs_sync_fs() -> write_checkpoint() calls stat_inc_cp_count(sbi->stat_info),
which needs stat_info allocation.
Otherwise, we can hit:

[254042.598623]  ? count_shadow_nodes+0xa0/0xa0
[254042.598633]  f2fs_sync_fs+0x65/0xd0 [f2fs]
[254042.598645]  f2fs_balance_fs_bg+0xe4/0x1c0 [f2fs]
[254042.598657]  f2fs_write_node_pages+0x34/0x1a0 [f2fs]
[254042.598664]  ? pagevec_lookup_entries+0x1e/0x30
[254042.598673]  do_writepages+0x1e/0x30
[254042.598682]  __writeback_single_inode+0x45/0x330
[254042.598688]  writeback_single_inode+0xd7/0x190
[254042.598694]  write_inode_now+0x86/0xa0
[254042.598699]  iput+0x122/0x200
[254042.598709]  f2fs_fill_super+0xd4a/0x14d0 [f2fs]
[254042.598717]  mount_bdev+0x184/0x1c0
[254042.598934]  ? f2fs_commit_super+0x100/0x100 [f2fs]
[254042.599142]  f2fs_mount+0x15/0x20 [f2fs]
[254042.599349]  mount_fs+0x39/0x160
[254042.599554]  ? __alloc_percpu+0x15/0x20
[254042.599759]  vfs_kern_mount+0x67/0x110
[254042.599972]  do_mount+0x1bb/0xc80
[254042.600175]  ? memdup_user+0x42/0x60
[254042.600380]  SyS_mount+0x83/0xd0
[254042.600583]  entry_SYSCALL_64_fastpath+0x1e/0xad
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/super.c

@@ -2022,6 +2022,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 
 	f2fs_join_shrinker(sbi);
 
+	err = f2fs_build_stats(sbi);
+	if (err)
+		goto free_nm;
+
 	/* if there are nt orphan nodes free them */
 	err = recover_orphan_inodes(sbi);
 	if (err)
@@ -2046,10 +2050,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_root_inode;
 	}
 
-	err = f2fs_build_stats(sbi);
-	if (err)
-		goto free_root_inode;
-
 	if (f2fs_proc_root)
 		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
 
@@ -2143,7 +2143,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		remove_proc_entry("segment_bits", sbi->s_proc);
 		remove_proc_entry(sb->s_id, f2fs_proc_root);
 	}
-	f2fs_destroy_stats(sbi);
 free_root_inode:
 	dput(sb->s_root);
 	sb->s_root = NULL;
@@ -2161,6 +2160,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 	truncate_inode_pages_final(META_MAPPING(sbi));
 	iput(sbi->node_inode);
 	mutex_unlock(&sbi->umount_mutex);
+	f2fs_destroy_stats(sbi);
 free_nm:
 	destroy_node_manager(sbi);
 free_sm: