[XFS] Always use struct xfs_btree_block instead of short / longform

structures.

Always use the generic xfs_btree_block type instead of the short / long
structures. Add XFS_BTREE_SBLOCK_LEN / XFS_BTREE_LBLOCK_LEN defines for
the length of a short / long form block. The rationale for this is that we
will grow more btree block header variants to support CRCs and other RAS
information, and always accessing them through the same datatype with
unions for the short / long form pointers makes implementing this much
easier.

SGI-PV: 988146

SGI-Modid: xfs-linux-melb:xfs-kern:32300a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 15 insertions, 38 deletions

diff --git a/fs/xfs/xfs_btree.h b/fs/xfs/xfs_btree.h
index d6120a749060..789fffdf8b2f 100644
--- a/fs/xfs/xfs_btree.h
+++ b/fs/xfs/xfs_btree.h
@@ -39,31 +39,16 @@ extern kmem_zone_t	*xfs_btree_cur_zone;
 #define XFS_BTNUM_INO   ((xfs_btnum_t)XFS_BTNUM_INOi)
 
 /*
- * Short form header: space allocation btrees.
- */
-typedef struct xfs_btree_sblock {
-        __be32          bb_magic;       /* magic number for block type */
-        __be16          bb_level;       /* 0 is a leaf */
-        __be16          bb_numrecs;     /* current # of data records */
-        __be32          bb_leftsib;     /* left sibling block or NULLAGBLOCK */
-        __be32          bb_rightsib;    /* right sibling block or NULLAGBLOCK */
-} xfs_btree_sblock_t;
-
-/*
- * Long form header: bmap btrees.
- */
-typedef struct xfs_btree_lblock {
-        __be32          bb_magic;       /* magic number for block type */
-        __be16          bb_level;       /* 0 is a leaf */
-        __be16          bb_numrecs;     /* current # of data records */
-        __be64          bb_leftsib;     /* left sibling block or NULLDFSBNO */
-        __be64          bb_rightsib;    /* right sibling block or NULLDFSBNO */
-} xfs_btree_lblock_t;
-
-/*
- * Combined header and structure, used by common code.
+ * Generic btree header.
+ *
+ * This is a comination of the actual format used on disk for short and long
+ * format btrees.  The first three fields are shared by both format, but
+ * the pointers are different and should be used with care.
+ *
+ * To get the size of the actual short or long form headers please use
+ * the size macros below.  Never use sizeof(xfs_btree_block).
  */
-typedef struct xfs_btree_block {
+struct xfs_btree_block {
         __be32          bb_magic;       /* magic number for block type */
         __be16          bb_level;       /* 0 is a leaf */
         __be16          bb_numrecs;     /* current # of data records */
@@ -77,7 +62,11 @@ typedef struct xfs_btree_block {
                         __be64          bb_rightsib;
                 } l;                    /* long form pointers */
         } bb_u;                         /* rest */
-} xfs_btree_block_t;
+};
+
+#define XFS_BTREE_SBLOCK_LEN    16      /* size of a short form block */
+#define XFS_BTREE_LBLOCK_LEN    24      /* size of a long form block */
+
 
 /*
  * Generic key, ptr and record wrapper structures.
@@ -294,20 +283,8 @@ typedef struct xfs_btree_cur
 /*
  * Convert from buffer to btree block header.
  */
-#define XFS_BUF_TO_BLOCK(bp)    ((xfs_btree_block_t *)XFS_BUF_PTR(bp))
-#define XFS_BUF_TO_LBLOCK(bp)   ((xfs_btree_lblock_t *)XFS_BUF_PTR(bp))
-#define XFS_BUF_TO_SBLOCK(bp)   ((xfs_btree_sblock_t *)XFS_BUF_PTR(bp))
-
+#define XFS_BUF_TO_BLOCK(bp)    ((struct xfs_btree_block *)XFS_BUF_PTR(bp))
 
-/*
- * Check that long form block header is ok.
- */
-int                                     /* error (0 or EFSCORRUPTED) */
-xfs_btree_check_lblock(
-        struct xfs_btree_cur    *cur,   /* btree cursor */
-        struct xfs_btree_lblock *block, /* btree long form block pointer */
-        int                     level,  /* level of the btree block */
-        struct xfs_buf          *bp);   /* buffer containing block, if any */
 
 /*
  * Check that block header is ok.