xfs: add version 3 inode format with CRCs

Add a new inode version with a larger core.  The primary objective is
to allow for a crc of the inode, and location information (uuid and ino)
to verify it was written in the right place.  We also extend it by:

	a creation time (for Samba);
	a changecount (for NFSv4);
	a flush sequence (in LSN format for recovery);
	an additional inode flags field; and
	some additional padding.

These additional fields are not implemented yet, but already laid
out in the structure.

[dchinner@redhat.com] Added LSN and flags field, some factoring and rework to
capture all the necessary information in the crc calculation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index b8520b5..9112979 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -150,13 +150,38 @@
 	__uint16_t	di_dmstate;	/* DMIG state info */
 	__uint16_t	di_flags;	/* random flags, XFS_DIFLAG_... */
 	__uint32_t	di_gen;		/* generation number */
+
+	/* di_next_unlinked is the only non-core field in the old dinode */
+	xfs_agino_t	di_next_unlinked;/* agi unlinked list ptr */
+
+	/* start of the extended dinode, writable fields */
+	__uint32_t	di_crc;		/* CRC of the inode */
+	__uint64_t	di_changecount;	/* number of attribute changes */
+	xfs_lsn_t	di_lsn;		/* flush sequence */
+	__uint64_t	di_flags2;	/* more random flags */
+	__uint8_t	di_pad2[16];	/* more padding for future expansion */
+
+	/* fields only written to during inode creation */
+	xfs_ictimestamp_t di_crtime;	/* time created */
+	xfs_ino_t	di_ino;		/* inode number */
+	uuid_t		di_uuid;	/* UUID of the filesystem */
+
+	/* structure must be padded to 64 bit alignment */
 } xfs_icdinode_t;
 
+static inline uint xfs_icdinode_size(int version)
+{
+	if (version == 3)
+		return sizeof(struct xfs_icdinode);
+	return offsetof(struct xfs_icdinode, di_next_unlinked);
+}
+
 /*
  * Flags for xfs_ichgtime().
  */
 #define	XFS_ICHGTIME_MOD	0x1	/* data fork modification timestamp */
 #define	XFS_ICHGTIME_CHG	0x2	/* inode field change timestamp */
+#define	XFS_ICHGTIME_CREATE	0x4	/* inode create timestamp */
 
 /*
  * Per-fork incore inode flags.
@@ -556,6 +581,7 @@
 			       struct xfs_buf **, uint, uint);
 int		xfs_iread(struct xfs_mount *, struct xfs_trans *,
 			  struct xfs_inode *, uint);
+void		xfs_dinode_calc_crc(struct xfs_mount *, struct xfs_dinode *);
 void		xfs_dinode_to_disk(struct xfs_dinode *,
 				   struct xfs_icdinode *);
 void		xfs_idestroy_fork(struct xfs_inode *, int);