eCryptfs: track header bytes rather than extents

Remove internal references to header extents; just keep track of header bytes
instead.  Headers can easily span multiple pages with the recent persistent
file changes.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index ed0ed84..a2bc9df 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -365,8 +365,7 @@
 		dentry->d_sb)->mount_crypt_stat;
 	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
-			file_size = ((crypt_stat->extent_size
-				      * crypt_stat->num_header_extents_at_front)
+			file_size = (crypt_stat->num_header_bytes_at_front
 				     + i_size_read(lower_dentry->d_inode));
 		else
 			file_size = i_size_read(lower_dentry->d_inode);
@@ -685,7 +684,7 @@
  * @crypt_stat: Crypt_stat associated with file
  * @upper_size: Size of the upper file
  *
- * Calculate the requried size of the lower file based on the
+ * Calculate the required size of the lower file based on the
  * specified size of the upper file. This calculation is based on the
  * number of headers in the underlying file and the extent size.
  *
@@ -697,8 +696,7 @@
 {
 	loff_t lower_size;
 
-	lower_size = (crypt_stat->extent_size
-		      * crypt_stat->num_header_extents_at_front);
+	lower_size = crypt_stat->num_header_bytes_at_front;
 	if (upper_size != 0) {
 		loff_t num_extents;