Revert "ecryptfs: modify write path to encrypt page in writepage"

fs/ecryptfs/ecryptfs_kernel.h

 /**
  * eCryptfs: Linux filesystem encryption layer
  * Kernel declarations.
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
  * Copyright (C) 2004-2008 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Trevor S. Highland <trevor.highland@gmail.com>
  *              Tyler Hicks <tyhicks@ou.edu>
@@ skipping 279 matching lines @@
         struct mutex cs_tfm_mutex;
         struct mutex cs_hash_tfm_mutex;
         struct mutex cs_mutex;
 };
 
 /* inode private data. */
 struct ecryptfs_inode_info {
         struct inode vfs_inode;
         struct inode *wii_inode;
         struct file *lower_file;
+        struct mutex lower_file_mutex;
         struct ecryptfs_crypt_stat crypt_stat;
 };
 
 /* dentry private data. Each dentry must keep track of a lower
  * vfsmount too. */
 struct ecryptfs_dentry_info {
         struct path lower_path;
         struct ecryptfs_crypt_stat *crypt_stat;
 };
 
@@ skipping 446 matching lines @@
                              char *filename, size_t filename_size);
 int
 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
                              size_t *packet_size,
                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
                              char *data, size_t max_packet_size);
 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
                        loff_t offset);
 
 #endif /* #ifndef ECRYPTFS_KERNEL_H */