diff -drupN a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c
--- a/fs/sdcardfs/super.c	1970-01-01 03:00:00.000000000 +0300
+++ b/fs/sdcardfs/super.c	2022-06-12 05:28:14.000000000 +0300
@@ -0,0 +1,331 @@
+/*
+ * fs/sdcardfs/super.c
+ *
+ * Copyright (c) 2013 Samsung Electronics Co. Ltd
+ *   Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
+ *               Sunghwan Yun, Sungjong Seo
+ *
+ * This program has been developed as a stackable file system based on
+ * the WrapFS which written by
+ *
+ * Copyright (c) 1998-2011 Erez Zadok
+ * Copyright (c) 2009     Shrikar Archak
+ * Copyright (c) 2003-2011 Stony Brook University
+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
+ *
+ * This file is dual licensed.  It may be redistributed and/or modified
+ * under the terms of the Apache 2.0 License OR version 2 of the GNU
+ * General Public License.
+ */
+
+#include "sdcardfs.h"
+
+/*
+ * The inode cache is used with alloc_inode for both our inode info and the
+ * vfs inode.
+ */
+static struct kmem_cache *sdcardfs_inode_cachep;
+
+/*
+ * To support the top references, we must track some data separately.
+ * An sdcardfs_inode_info always has a reference to its data, and once set up,
+ * also has a reference to its top. The top may be itself, in which case it
+ * holds two references to its data. When top is changed, it takes a ref to the
+ * new data and then drops the ref to the old data.
+ */
+static struct kmem_cache *sdcardfs_inode_data_cachep;
+
+void data_release(struct kref *ref)
+{
+	struct sdcardfs_inode_data *data =
+		container_of(ref, struct sdcardfs_inode_data, refcount);
+
+	kmem_cache_free(sdcardfs_inode_data_cachep, data);
+}
+
+/* final actions when unmounting a file system */
+static void sdcardfs_put_super(struct super_block *sb)
+{
+	struct sdcardfs_sb_info *spd;
+	struct super_block *s;
+
+	spd = SDCARDFS_SB(sb);
+	if (!spd)
+		return;
+
+	if (spd->obbpath_s) {
+		kfree(spd->obbpath_s);
+		path_put(&spd->obbpath);
+	}
+
+	/* decrement lower super references */
+	s = sdcardfs_lower_super(sb);
+	sdcardfs_set_lower_super(sb, NULL);
+	atomic_dec(&s->s_active);
+
+	kfree(spd);
+	sb->s_fs_info = NULL;
+}
+
+static int sdcardfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	int err;
+	struct path lower_path;
+	u32 min_blocks;
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+
+	sdcardfs_get_lower_path(dentry, &lower_path);
+	err = vfs_statfs(&lower_path, buf);
+	sdcardfs_put_lower_path(dentry, &lower_path);
+
+	if (sbi->options.reserved_mb) {
+		/* Invalid statfs informations. */
+		if (buf->f_bsize == 0) {
+			pr_err("Returned block size is zero.\n");
+			return -EINVAL;
+		}
+
+		min_blocks = ((sbi->options.reserved_mb * 1024 * 1024)/buf->f_bsize);
+		buf->f_blocks -= min_blocks;
+
+		if (buf->f_bavail > min_blocks)
+			buf->f_bavail -= min_blocks;
+		else
+			buf->f_bavail = 0;
+
+		/* Make reserved blocks invisiable to media storage */
+		buf->f_bfree = buf->f_bavail;
+	}
+
+	/* set return buf to our f/s to avoid confusing user-level utils */
+	buf->f_type = SDCARDFS_SUPER_MAGIC;
+
+	return err;
+}
+
+/*
+ * @flags: numeric mount options
+ * @options: mount options string
+ */
+static int sdcardfs_remount_fs(struct super_block *sb, int *flags, char *options)
+{
+	int err = 0;
+
+	/*
+	 * The VFS will take care of "ro" and "rw" flags among others.  We
+	 * can safely accept a few flags (RDONLY, MANDLOCK), and honor
+	 * SILENT, but anything else left over is an error.
+	 */
+	if ((*flags & ~(MS_RDONLY | MS_MANDLOCK | MS_SILENT)) != 0) {
+		pr_err("sdcardfs: remount flags 0x%x unsupported\n", *flags);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+/*
+ * @mnt: mount point we are remounting
+ * @sb: superblock we are remounting
+ * @flags: numeric mount options
+ * @options: mount options string
+ */
+static int sdcardfs_remount_fs2(struct vfsmount *mnt, struct super_block *sb,
+						int *flags, char *options)
+{
+	int err = 0;
+
+	/*
+	 * The VFS will take care of "ro" and "rw" flags among others.  We
+	 * can safely accept a few flags (RDONLY, MANDLOCK), and honor
+	 * SILENT, but anything else left over is an error.
+	 */
+	if ((*flags & ~(MS_RDONLY | MS_MANDLOCK | MS_SILENT | MS_REMOUNT)) != 0) {
+		pr_err("sdcardfs: remount flags 0x%x unsupported\n", *flags);
+		err = -EINVAL;
+	}
+	pr_info("Remount options were %s for vfsmnt %p.\n", options, mnt);
+	err = parse_options_remount(sb, options, *flags & ~MS_SILENT, mnt->data);
+
+
+	return err;
+}
+
+static void *sdcardfs_clone_mnt_data(void *data)
+{
+	struct sdcardfs_vfsmount_options *opt = kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
+	struct sdcardfs_vfsmount_options *old = data;
+
+	if (!opt)
+		return NULL;
+	opt->gid = old->gid;
+	opt->mask = old->mask;
+	return opt;
+}
+
+static void sdcardfs_copy_mnt_data(void *data, void *newdata)
+{
+	struct sdcardfs_vfsmount_options *old = data;
+	struct sdcardfs_vfsmount_options *new = newdata;
+
+	old->gid = new->gid;
+	old->mask = new->mask;
+}
+
+/*
+ * Called by iput() when the inode reference count reached zero
+ * and the inode is not hashed anywhere.  Used to clear anything
+ * that needs to be, before the inode is completely destroyed and put
+ * on the inode free list.
+ */
+static void sdcardfs_evict_inode(struct inode *inode)
+{
+	struct inode *lower_inode;
+
+	truncate_inode_pages(&inode->i_data, 0);
+	set_top(SDCARDFS_I(inode), NULL);
+	clear_inode(inode);
+	/*
+	 * Decrement a reference to a lower_inode, which was incremented
+	 * by our read_inode when it was created initially.
+	 */
+	lower_inode = sdcardfs_lower_inode(inode);
+	sdcardfs_set_lower_inode(inode, NULL);
+	iput(lower_inode);
+}
+
+static struct inode *sdcardfs_alloc_inode(struct super_block *sb)
+{
+	struct sdcardfs_inode_info *i;
+	struct sdcardfs_inode_data *d;
+
+	i = kmem_cache_alloc(sdcardfs_inode_cachep, GFP_KERNEL);
+	if (!i)
+		return NULL;
+
+	/* memset everything up to the inode to 0 */
+	memset(i, 0, offsetof(struct sdcardfs_inode_info, vfs_inode));
+
+	d = kmem_cache_alloc(sdcardfs_inode_data_cachep,
+					GFP_KERNEL | __GFP_ZERO);
+	if (!d) {
+		kmem_cache_free(sdcardfs_inode_cachep, i);
+		return NULL;
+	}
+
+	i->data = d;
+	kref_init(&d->refcount);
+	i->top_data = d;
+	spin_lock_init(&i->top_lock);
+	kref_get(&d->refcount);
+
+	i->vfs_inode.i_version = 1;
+	return &i->vfs_inode;
+}
+
+static void i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+
+	release_own_data(SDCARDFS_I(inode));
+	kmem_cache_free(sdcardfs_inode_cachep, SDCARDFS_I(inode));
+}
+
+static void sdcardfs_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, i_callback);
+}
+
+/* sdcardfs inode cache constructor */
+static void init_once(void *obj)
+{
+	struct sdcardfs_inode_info *i = obj;
+
+	inode_init_once(&i->vfs_inode);
+}
+
+int sdcardfs_init_inode_cache(void)
+{
+	sdcardfs_inode_cachep =
+		kmem_cache_create("sdcardfs_inode_cache",
+				  sizeof(struct sdcardfs_inode_info), 0,
+				  SLAB_RECLAIM_ACCOUNT, init_once);
+
+	if (!sdcardfs_inode_cachep)
+		return -ENOMEM;
+
+	sdcardfs_inode_data_cachep =
+		kmem_cache_create("sdcardfs_inode_data_cache",
+				  sizeof(struct sdcardfs_inode_data), 0,
+				  SLAB_RECLAIM_ACCOUNT, NULL);
+	if (!sdcardfs_inode_data_cachep) {
+		kmem_cache_destroy(sdcardfs_inode_cachep);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/* sdcardfs inode cache destructor */
+void sdcardfs_destroy_inode_cache(void)
+{
+	kmem_cache_destroy(sdcardfs_inode_data_cachep);
+	kmem_cache_destroy(sdcardfs_inode_cachep);
+}
+
+/*
+ * Used only in nfs, to kill any pending RPC tasks, so that subsequent
+ * code can actually succeed and won't leave tasks that need handling.
+ */
+static void sdcardfs_umount_begin(struct super_block *sb)
+{
+	struct super_block *lower_sb;
+
+	lower_sb = sdcardfs_lower_super(sb);
+	if (lower_sb && lower_sb->s_op && lower_sb->s_op->umount_begin)
+		lower_sb->s_op->umount_begin(lower_sb);
+}
+
+static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m,
+			struct dentry *root)
+{
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(root->d_sb);
+	struct sdcardfs_mount_options *opts = &sbi->options;
+	struct sdcardfs_vfsmount_options *vfsopts = mnt->data;
+
+	if (opts->fs_low_uid != 0)
+		seq_printf(m, ",fsuid=%u", opts->fs_low_uid);
+	if (opts->fs_low_gid != 0)
+		seq_printf(m, ",fsgid=%u", opts->fs_low_gid);
+	if (vfsopts->gid != 0)
+		seq_printf(m, ",gid=%u", vfsopts->gid);
+	if (opts->multiuser)
+		seq_puts(m, ",multiuser");
+	if (vfsopts->mask)
+		seq_printf(m, ",mask=%u", vfsopts->mask);
+	if (opts->fs_user_id)
+		seq_printf(m, ",userid=%u", opts->fs_user_id);
+	if (opts->gid_derivation)
+		seq_puts(m, ",derive_gid");
+	if (opts->default_normal)
+		seq_puts(m, ",default_normal");
+	if (opts->reserved_mb != 0)
+		seq_printf(m, ",reserved=%uMB", opts->reserved_mb);
+
+	return 0;
+};
+
+const struct super_operations sdcardfs_sops = {
+	.put_super	= sdcardfs_put_super,
+	.statfs		= sdcardfs_statfs,
+	.remount_fs	= sdcardfs_remount_fs,
+	.remount_fs2	= sdcardfs_remount_fs2,
+	.clone_mnt_data	= sdcardfs_clone_mnt_data,
+	.copy_mnt_data	= sdcardfs_copy_mnt_data,
+	.evict_inode	= sdcardfs_evict_inode,
+	.umount_begin	= sdcardfs_umount_begin,
+	.show_options2	= sdcardfs_show_options,
+	.alloc_inode	= sdcardfs_alloc_inode,
+	.destroy_inode	= sdcardfs_destroy_inode,
+	.drop_inode	= generic_delete_inode,
+};