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

fs/ecryptfs/read_write.c

 /**
  * eCryptfs: Linux filesystem encryption layer
  *
  * Copyright (C) 2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
@@ skipping 26 matching lines @@
  * Returns bytes written on success; less than zero on error
  */
 int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
                          loff_t offset, size_t size)
 {
         struct ecryptfs_inode_info *inode_info;
         mm_segment_t fs_save;
         ssize_t rc;
 
         inode_info = ecryptfs_inode_to_private(ecryptfs_inode);
+        mutex_lock(&inode_info->lower_file_mutex);
         BUG_ON(!inode_info->lower_file);
+        inode_info->lower_file->f_pos = offset;
         fs_save = get_fs();
         set_fs(get_ds());
-        rc = vfs_write(inode_info->lower_file, data, size, &offset);
+        rc = vfs_write(inode_info->lower_file, data, size,
+                       &inode_info->lower_file->f_pos);
         set_fs(fs_save);
+        mutex_unlock(&inode_info->lower_file_mutex);
         mark_inode_dirty_sync(ecryptfs_inode);
         return rc;
 }
 
 /**
  * ecryptfs_write_lower_page_segment
  * @ecryptfs_inode: The eCryptfs inode
  * @page_for_lower: The page containing the data to be written to the
  *                  lower file
  * @offset_in_page: The offset in the @page_for_lower from which to
@@ skipping 162 matching lines @@
  * Returns bytes read on success; 0 on EOF; less than zero on error
  */
 int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
                         struct inode *ecryptfs_inode)
 {
         struct ecryptfs_inode_info *inode_info =
                 ecryptfs_inode_to_private(ecryptfs_inode);
         mm_segment_t fs_save;
         ssize_t rc;
 
+        mutex_lock(&inode_info->lower_file_mutex);
         BUG_ON(!inode_info->lower_file);
+        inode_info->lower_file->f_pos = offset;
         fs_save = get_fs();
         set_fs(get_ds());
-        rc = vfs_read(inode_info->lower_file, data, size, &offset);
+        rc = vfs_read(inode_info->lower_file, data, size,
+                      &inode_info->lower_file->f_pos);
         set_fs(fs_save);
+        mutex_unlock(&inode_info->lower_file_mutex);
         return rc;
 }
 
 /**
  * ecryptfs_read_lower_page_segment
  * @page_for_ecryptfs: The page into which data for eCryptfs will be
  *                     written
  * @offset_in_page: Offset in @page_for_ecryptfs from which to start
  *                  writing
  * @size: The number of bytes to write into @page_for_ecryptfs
@@ skipping 89 matching lines @@
                 SetPageUptodate(ecryptfs_page);
                 unlock_page(ecryptfs_page);
                 page_cache_release(ecryptfs_page);
                 pos += num_bytes;
                 data_offset += num_bytes;
         }
 out:
         return rc;
 }
 #endif  /*  0  */