+
 /*
  * shmem_file_setup pre-accounts the whole fixed size of a VM object,
  * for shared memory and for shared anonymous (/dev/zero) mappings

@@ -2859,8 +2869,18 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	struct inode *inode;
 	int error = -ENOSPC;
 
+#ifdef CONFIG_UNICODE
+	struct super_block *sb = dir->i_sb;
+
+	if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) &&
+	    sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
+		return -EINVAL;
+#endif
+
 	inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
 	if (inode) {
+		inode->i_flags |= dir->i_flags;
+
 		error = simple_acl_create(dir, inode);
 		if (error)
 			goto out_iput;

@@ -2870,6 +2890,9 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 		if (error && error != -EOPNOTSUPP)
 			goto out_iput;
 
+		if (IS_CASEFOLDED(dir))
+			d_add(dentry, NULL);
+
 		error = 0;
 		dir->i_size += BOGO_DIRENT_SIZE;
 		dir->i_ctime = dir->i_mtime = current_time(dir);

@@ -2925,6 +2948,19 @@ static int shmem_create(struct user_namespace *mnt_userns, struct inode *dir,
 	return shmem_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
 }
 
+static struct dentry *shmem_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	if (IS_CASEFOLDED(dir))
+		return NULL;

+
+	d_add(dentry, NULL);
+
+	return NULL;
+}
+
 /*
  * Link a file..
  */

@@ -2946,6 +2982,9 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr
 			goto out;
 	}
 
+	if (IS_CASEFOLDED(dir))
+		d_add(dentry, NULL);
+
 	dir->i_size += BOGO_DIRENT_SIZE;
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
 	inc_nlink(inode);

@@ -2967,6 +3006,10 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
 	drop_nlink(inode);
 	dput(dentry);	/* Undo the count from "create" - this does all the work */
+
+	if (IS_CASEFOLDED(dir))
+		d_invalidate(dentry);
+
 	return 0;
 }
 

@@ -3128,6 +3171,8 @@ static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 	}
 	dir->i_size += BOGO_DIRENT_SIZE;
 	dir->i_ctime = dir->i_mtime = current_time(dir);
+	if (IS_CASEFOLDED(dir))
+		d_add(dentry, NULL);
 	d_instantiate(dentry, inode);
 	dget(dentry);
 	return 0;

@@ -3364,6 +3409,8 @@ enum shmem_param {
 	Opt_uid,
 	Opt_inode32,
 	Opt_inode64,
+	Opt_casefold,
+	Opt_cf_strict,
 };
 
 static const struct constant_table shmem_param_enums_huge[] = {

@@ -3385,6 +3432,8 @@ const struct fs_parameter_spec shmem_fs_parameters[] = {
 	fsparam_u32   ("uid",		Opt_uid),
 	fsparam_flag  ("inode32",	Opt_inode32),
 	fsparam_flag  ("inode64",	Opt_inode64),
+	fsparam_string("casefold",	Opt_casefold),
+	fsparam_flag  ("cf_strict",	Opt_cf_strict),
 	{}
 };
 

@@ -3392,9 +3441,11 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 {
 	struct shmem_options *ctx = fc->fs_private;
 	struct fs_parse_result result;
+	struct unicode_map *encoding;
 	unsigned long long size;
+	char version[10];
 	char *rest;
-	int opt;
+	int opt, ret;
 
 	opt = fs_parse(fc, shmem_fs_parameters, param, &result);
 	if (opt < 0)

@@ -3468,6 +3519,23 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 		ctx->full_inums = true;
 		ctx->seen |= SHMEM_SEEN_INUMS;
 		break;
+	case Opt_casefold:
+		if (strncmp(param->string, "utf8-", 5))
+			return invalfc(fc, "Only utf8 encondings are supported");
+		ret = strscpy(version, param->string + 5, sizeof(version));