ocfs2: Add the on-disk structures for metadata checksums.

Define struct ocfs2_block_check, an 8-byte structure containing a 32bit
crc32_le and a 16bit hamming code ecc.  This will be used for metadata
checksums.  Add the structure to free spaces in the various metadata
structures.

Add the OCFS2_FEATURE_INCOMPAT_META_ECC bit.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 50 insertions, 5 deletions

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 359732e18e82..290fa26fba6e 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -149,6 +149,9 @@
 /* Support for extended attributes */
 #define OCFS2_FEATURE_INCOMPAT_XATTR            0x0200
 
+/* Metadata checksum and error correction */
+#define OCFS2_FEATURE_INCOMPAT_META_ECC         0x0800
+
 /*
  * backup superblock flag is used to indicate that this volume
  * has backup superblocks.
@@ -427,6 +430,22 @@ static unsigned char ocfs2_type_by_mode[S_IFMT >> S_SHIFT] = {
 #define OCFS2_RAW_SB(dinode)            (&((dinode)->id2.i_super))
 
 /*
+ * Block checking structure.  This is used in metadata to validate the
+ * contents.  If OCFS2_FEATURE_INCOMPAT_META_ECC is not set, it is all
+ * zeros.
+ */
+struct ocfs2_block_check {
+/*00*/  __le32 bc_crc32e;       /* 802.3 Ethernet II CRC32 */
+        __le16 bc_ecc;          /* Single-error-correction parity vector.
+                                   This is a simple Hamming code dependant
+                                   on the blocksize.  OCFS2's maximum
+                                   blocksize, 4K, requires 16 parity bits,
+                                   so we fit in __le16. */
+        __le16 bc_reserved1;
+/*08*/
+};
+
+/*
  * On disk extent record for OCFS2
  * It describes a range of clusters on disk.
  *
@@ -513,7 +532,7 @@ struct ocfs2_truncate_log {
 struct ocfs2_extent_block
 {
 /*00*/  __u8 h_signature[8];            /* Signature for verification */
-        __le64 h_reserved1;
+        struct ocfs2_block_check h_check;       /* Error checking */
 /*10*/  __le16 h_suballoc_slot;         /* Slot suballocator this
                                            extent_header belongs to */
         __le16 h_suballoc_bit;          /* Bit offset in suballocator
@@ -683,7 +702,8 @@ struct ocfs2_dinode {
                                            was set in i_flags */
         __le16 i_dyn_features;
         __le64 i_xattr_loc;
-/*80*/  __le64 i_reserved2[7];
+/*80*/  struct ocfs2_block_check i_check;       /* Error checking */
+/*88*/  __le64 i_reserved2[6];
 /*B8*/  union {
                 __le64 i_pad1;          /* Generic way to refer to this
                                            64bit union */
@@ -750,7 +770,8 @@ struct ocfs2_group_desc
 /*20*/  __le64   bg_parent_dinode;       /* dinode which owns me, in
                                            blocks */
         __le64   bg_blkno;               /* Offset on disk, in blocks */
-/*30*/  __le64   bg_reserved2[2];
+/*30*/  struct ocfs2_block_check bg_check;      /* Error checking */
+        __le64   bg_reserved2;
 /*40*/  __u8    bg_bitmap[0];
 };
 
@@ -793,7 +814,12 @@ struct ocfs2_xattr_header {
                                                    in this extent record,
                                                    only valid in the first
                                                    bucket. */
-        __le64  xh_csum;
+        struct ocfs2_block_check xh_check;      /* Error checking
+                                                   (Note, this is only
+                                                    used for xattr
+                                                    buckets.  A block uses
+                                                    xb_check and sets
+                                                    this field to zero.) */
         struct ocfs2_xattr_entry xh_entries[0]; /* xattr entry list. */
 };
 
@@ -844,7 +870,7 @@ struct ocfs2_xattr_block {
                                         block group */
         __le32  xb_fs_generation;    /* Must match super block */
 /*10*/  __le64  xb_blkno;            /* Offset on disk, in blocks */
-        __le64  xb_csum;
+        struct ocfs2_block_check xb_check;      /* Error checking */
 /*20*/  __le16  xb_flags;            /* Indicates whether this block contains
                                         real xattr or a xattr tree. */
         __le16  xb_reserved0;
@@ -988,6 +1014,25 @@ struct ocfs2_local_disk_dqblk {
 /*10*/  __le64 dqb_inodemod;    /* Change in the amount of used inodes */
 };
 
+
+/*
+ * The quota trailer lives at the end of each quota block.
+ */
+
+struct ocfs2_disk_dqtrailer {
+/*00*/  struct ocfs2_block_check dq_check;      /* Error checking */
+/*08*/  /* Cannot be larger than OCFS2_QBLK_RESERVED_SPACE */
+};
+
+static inline struct ocfs2_disk_dqtrailer *ocfs2_block_dqtrailer(int blocksize,
+                                                                 void *buf)
+{
+        char *ptr = buf;
+        ptr += blocksize - OCFS2_QBLK_RESERVED_SPACE;
+
+        return (struct ocfs2_disk_dqtrailer *)ptr;
+}
+
 #ifdef __KERNEL__
 static inline int ocfs2_fast_symlink_chars(struct super_block *sb)
 {