--- zzzz-none-000/linux-3.10.107/fs/ecryptfs/main.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/ecryptfs/main.c	2021-02-04 17:41:59.000000000 +0000
@@ -120,16 +120,15 @@
 				    struct file **lower_file)
 {
 	const struct cred *cred = current_cred();
-	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	struct path *path = ecryptfs_dentry_to_lower_path(dentry);
 	int rc;
 
-	rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
+	rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
 				      cred);
 	if (rc) {
 		printk(KERN_ERR "Error opening lower file "
 		       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
-		       "rc = [%d]\n", lower_dentry, lower_mnt, rc);
+		       "rc = [%d]\n", path->dentry, path->mnt, rc);
 		(*lower_file) = NULL;
 	}
 	return rc;
@@ -408,7 +407,7 @@
 	if (!cipher_name_set) {
 		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 
-		BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+		BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 		strcpy(mount_crypt_stat->global_default_cipher_name,
 		       ECRYPTFS_DEFAULT_CIPHER);
 	}
@@ -521,7 +520,7 @@
 		goto out;
 	}
 
-	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
+	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
 	if (rc)
 		goto out1;
 
@@ -547,11 +546,11 @@
 		goto out_free;
 	}
 
-	if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
+	if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 		rc = -EPERM;
 		printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 		       "requested user (uid: %d)\n",
-			i_uid_read(path.dentry->d_inode),
+			i_uid_read(d_inode(path.dentry)),
 			from_kuid(&init_user_ns, current_uid()));
 		goto out_free;
 	}
@@ -577,8 +576,15 @@
 	s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 	s->s_blocksize = path.dentry->d_sb->s_blocksize;
 	s->s_magic = ECRYPTFS_SUPER_MAGIC;
+	s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 
-	inode = ecryptfs_get_inode(path.dentry->d_inode, s);
+	rc = -EINVAL;
+	if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
+		pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
+		goto out_free;
+	}
+
+	inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 	rc = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_free;
@@ -596,8 +602,7 @@
 
 	/* ->kill_sb() will take care of root_info */
 	ecryptfs_set_dentry_private(s->s_root, root_info);
-	ecryptfs_set_dentry_lower(s->s_root, path.dentry);
-	ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
+	root_info->lower_path = path;
 
 	s->s_flags |= MS_ACTIVE;
 	return dget(s->s_root);