ext4: verify and calculate checksums for extent tree blocks

[linux-2.6-microblaze.git] / fs / ext4 / ext4_extents.h

diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 94822e7..cb1b2c9 100644 (file)
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -114,6 +114,17 @@ struct ext4_extent_header {
 
 #define EXT4_EXT_MAGIC         cpu_to_le16(0xf30a)
 
+#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
+       (sizeof(struct ext4_extent_header) + \
+        (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max)))
+
+static inline struct ext4_extent_tail *
+find_ext4_extent_tail(struct ext4_extent_header *eh)
+{
+       return (struct ext4_extent_tail *)(((void *)eh) +
+                                          EXT4_EXTENT_TAIL_OFFSET(eh));
+}
+
 /*
  * Array of ext4_ext_path contains path to some extent.
  * Creation/lookup routines use it for traversal/splitting/etc.