From 7ac5990d5a3e2e465162880819cc46c6427d3b6f Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Sun, 29 Apr 2012 18:37:10 -0400 Subject: ext4: verify and calculate checksums for extent tree blocks Calculate and verify the checksum for each extent tree block. The checksum is located in the space immediately after the last possible ext4_extent in the block. The space is is typically the last 4-8 bytes in the block. Signed-off-by: Darrick J. Wong Signed-off-by: "Theodore Ts'o" --- fs/ext4/ext4_extents.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'fs/ext4/ext4_extents.h') diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h index 94822e74ef73..cb1b2c919963 100644 --- 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. -- cgit v1.2.3