[PATCH 03/26] add generic btree types

[Christoph Hellwig <hch@xxxxxx>]

Add generic union types for btree pointers, keys and records.  The generic
btree pointer contains a 32 and 64bit big endian type for short and long
form btrees, and the key and record contain the relevant type for each
possible btree.

Split out from a bigger patch from Dave Chinner and simplified a little
further.


Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Index: linux-2.6-xfs/fs/xfs/xfs_btree.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_btree.h       2008-08-02 04:01:46.000000000 
+0200
+++ linux-2.6-xfs/fs/xfs/xfs_btree.h    2008-08-02 04:04:16.000000000 +0200
@@ -79,6 +79,31 @@ typedef struct xfs_btree_block {
        } bb_u;                         /* rest */
 } xfs_btree_block_t;
 
+ /*
+  * Generic key, ptr and record wrapper structures.
+  *
+  * These are disk format structures, and are converted where necessary
+  * by the btree specific code that needs to interpret them.
+  */
+union xfs_btree_ptr {
+       __be32                  s;      /* short form ptr */
+       __be64                  l;      /* long form ptr */
+};
+
+union xfs_btree_key {
+       xfs_bmbt_key_t          bmbt;
+       xfs_bmdr_key_t          bmbr;   /* bmbt root block */
+       xfs_alloc_key_t         alloc;
+       xfs_inobt_key_t         inobt;
+};
+
+union xfs_btree_rec {
+       xfs_bmbt_rec_t          bmbt;
+       xfs_bmdr_rec_t          bmbr;   /* bmbt root block */
+       xfs_alloc_rec_t         alloc;
+       xfs_inobt_rec_t         inobt;
+};
+
 /*
  * For logging record fields.
  */

--