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

fs/ecryptfs/main.c

 /**
  * eCryptfs: Linux filesystem encryption layer
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
  * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Michael C. Thompson <mcthomps@us.ibm.com>
  *              Tyler Hicks <tyhicks@ou.edu>
  *
@@ skipping 104 matching lines @@
  * Returns zero on success; non-zero otherwise
  */
 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 {
         const struct cred *cred = current_cred();
         struct ecryptfs_inode_info *inode_info =
                 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
         int opened_lower_file = 0;
         int rc = 0;
 
+        mutex_lock(&inode_info->lower_file_mutex);
         if (!inode_info->lower_file) {
                 struct dentry *lower_dentry;
                 struct vfsmount *lower_mnt =
                         ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 
                 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
                 rc = ecryptfs_privileged_open(&inode_info->lower_file,
                                               lower_dentry, lower_mnt, cred);
                 if (rc) {
                         printk(KERN_ERR "Error opening lower persistent file "
                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
                         inode_info->lower_file = NULL;
                 } else
                         opened_lower_file = 1;
         }
+        mutex_unlock(&inode_info->lower_file_mutex);
         if (opened_lower_file)
                 ima_counts_get(inode_info->lower_file);
         return rc;
 }
 
 /**
  * ecryptfs_interpose
  * @lower_dentry: Existing dentry in the lower filesystem
  * @dentry: ecryptfs' dentry
  * @sb: ecryptfs's super_block
@@ skipping 745 matching lines @@
         ecryptfs_free_kmem_caches();
 }
 
 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 MODULE_DESCRIPTION("eCryptfs");
 
 MODULE_LICENSE("GPL");
 
 module_init(ecryptfs_init)
 module_exit(ecryptfs_exit)