xfs: cull unnecessary icdinode fields

Now that the struct xfs_icdinode is not directly related to the
on-disk format, we can cull things in it we really don't need to
store:

	- magic number never changes
	- padding is not necessary
	- next_unlinked is never used
	- inode number is redundant
	- uuid is redundant
	- lsn is accessed directly from dinode
	- inode CRC is only accessed directly from dinode

Hence we can remove these from the struct xfs_icdinode and redirect
the code that uses them to the xfs_dinode appripriately.  This
reduces the size of the struct icdinode from 152 bytes to 88 bytes,
and removes a fair chunk of unnecessary code, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 6 insertions, 19 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_buf.h b/fs/xfs/libxfs/xfs_inode_buf.h
index adcc9bfe02e9..7b8b1b97918b 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.h
+++ b/fs/xfs/libxfs/xfs_inode_buf.h
@@ -22,24 +22,22 @@ struct xfs_inode;
 struct xfs_dinode;
 
 /*
- * In memory representation of the XFS inode. This is held in the in-core
- * struct xfs_inode to represent the on disk values, but no longer needs to be
- * identical to the on-disk structure as it is always translated to on-disk
+ * In memory representation of the XFS inode. This is held in the in-core struct
+ * xfs_inode and represents the current on disk values but the structure is not
+ * in on-disk format.  That is, this structure is always translated to on-disk
  * format specific structures at the appropriate time.
  */
 struct xfs_icdinode {
-	__uint16_t	di_magic;	/* inode magic # = XFS_DINODE_MAGIC */
 	__uint16_t	di_mode;	/* mode and type of file */
 	__int8_t	di_version;	/* inode version */
 	__int8_t	di_format;	/* format of di_c data */
 	__uint16_t	di_onlink;	/* old number of links to file */
+	__uint16_t	di_flushiter;	/* incremented on flush */
 	__uint32_t	di_uid;		/* owner's user id */
 	__uint32_t	di_gid;		/* owner's group id */
 	__uint32_t	di_nlink;	/* number of links to file */
 	__uint16_t	di_projid_lo;	/* lower part of owner's project id */
 	__uint16_t	di_projid_hi;	/* higher part of owner's project id */
-	__uint8_t	di_pad[6];	/* unused, zeroed space */
-	__uint16_t	di_flushiter;	/* incremented on flush */
 	xfs_fsize_t	di_size;	/* number of bytes in file */
 	xfs_rfsblock_t	di_nblocks;	/* # of direct & btree blocks used */
 	xfs_extlen_t	di_extsize;	/* basic/minimum extent size for file */
@@ -52,22 +50,10 @@ struct xfs_icdinode {
 	__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 */
 };
 
 /*
@@ -86,7 +72,8 @@ int	xfs_imap_to_bp(struct xfs_mount *, struct xfs_trans *,
 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_inode_to_disk(struct xfs_inode *ip, struct xfs_dinode *to);
+void	xfs_inode_to_disk(struct xfs_inode *ip, struct xfs_dinode *to,
+			  xfs_lsn_t lsn);
 void	xfs_inode_from_disk(struct xfs_inode *ip, struct xfs_dinode *from);
 void	xfs_log_dinode_to_disk(struct xfs_log_dinode *from,
 			       struct xfs_dinode *to);