xfs: reshuffle dir2 headers

Replace the current mess of dir2 headers with just three that have a clear
purpose:

 - xfs_dir2_format.h for all format definitions, including the inline helpers
   to access our variable size structures
 - xfs_dir2_priv.h for all prototypes that are internal to the dir2 code
   and not needed by anything outside of the directory code.  For this
   purpose xfs_da_btree.c, and phase6.c in xfs_repair are considered part
   of the directory code.
 - xfs_dir2.h for the public interface to the directory code

In addition to the reshuffle I have also update the comments to not only
match the new file structure, but also to describe the directory format
better.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

16 files changed, 751 insertions, 900 deletions

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 2ce6aa644e7..c51a3f90363 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -29,15 +29,11 @@
 #include "xfs_bmap_btree.h"
 #include "xfs_alloc_btree.h"
 #include "xfs_ialloc_btree.h"
-#include "xfs_dir2_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_btree.h"
 #include "xfs_mount.h"
 #include "xfs_itable.h"
-#include "xfs_dir2_data.h"
-#include "xfs_dir2_leaf.h"
-#include "xfs_dir2_block.h"
 #include "xfs_inode_item.h"
 #include "xfs_extfree_item.h"
 #include "xfs_alloc.h"
diff --git a/fs/xfs/xfs_da_btree.c b/fs/xfs/xfs_da_btree.c
index 18425717cbe..a58a6410c58 100644
--- a/fs/xfs/xfs_da_btree.c
+++ b/fs/xfs/xfs_da_btree.c
@@ -24,11 +24,12 @@
 #include "xfs_trans.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
-#include "xfs_dir2.h"
 #include "xfs_mount.h"
 #include "xfs_da_btree.h"
 #include "xfs_bmap_btree.h"
-#include "xfs_dir2_sf.h"
+#include "xfs_dir2.h"
+#include "xfs_dir2_format.h"
+#include "xfs_dir2_priv.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
@@ -36,10 +37,6 @@
 #include "xfs_bmap.h"
 #include "xfs_attr.h"
 #include "xfs_attr_leaf.h"
-#include "xfs_dir2_data.h"
-#include "xfs_dir2_leaf.h"
-#include "xfs_dir2_block.h"
-#include "xfs_dir2_node.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
 
diff --git a/fs/xfs/xfs_dir2.c b/fs/xfs/xfs_dir2.c
index 0dee57812f4..6effbeb24e5 100644
--- a/fs/xfs/xfs_dir2.c
+++ b/fs/xfs/xfs_dir2.c
@@ -24,20 +24,17 @@
 #include "xfs_trans.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
-#include "xfs_dir2.h"
 #include "xfs_mount.h"
 #include "xfs_da_btree.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_alloc_btree.h"
-#include "xfs_dir2_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
 #include "xfs_bmap.h"
-#include "xfs_dir2_data.h"
-#include "xfs_dir2_leaf.h"
-#include "xfs_dir2_block.h"
-#include "xfs_dir2_node.h"
+#include "xfs_dir2.h"
+#include "xfs_dir2_format.h"
+#include "xfs_dir2_priv.h"
 #include "xfs_error.h"
 #include "xfs_vnodeops.h"
 #include "xfs_trace.h"
diff --git a/fs/xfs/xfs_dir2.h b/fs/xfs/xfs_dir2.h
index 74a3b105768..e937d9991c1 100644
--- a/fs/xfs/xfs_dir2.h
+++ b/fs/xfs/xfs_dir2.h
@@ -16,49 +16,14 @@
  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 #ifndef __XFS_DIR2_H__
-#define	__XFS_DIR2_H__
+#define __XFS_DIR2_H__
 
-struct uio;
-struct xfs_dabuf;
-struct xfs_da_args;
-struct xfs_dir2_put_args;
 struct xfs_bmap_free;
+struct xfs_da_args;
 struct xfs_inode;
 struct xfs_mount;
 struct xfs_trans;
 
-/*
- * Directory version 2.
- * There are 4 possible formats:
- *	shortform
- *	single block - data with embedded leaf at the end
- *	multiple data blocks, single leaf+freeindex block
- *	data blocks, node&leaf blocks (btree), freeindex blocks
- *
- *	The shortform format is in xfs_dir2_sf.h.
- *	The single block format is in xfs_dir2_block.h.
- *	The data block format is in xfs_dir2_data.h.
- *	The leaf and freeindex block formats are in xfs_dir2_leaf.h.
- *	Node blocks are the same as the other version, in xfs_da_btree.h.
- */
-
-/*
- * Byte offset in data block and shortform entry.
- */
-typedef	__uint16_t	xfs_dir2_data_off_t;
-#define	NULLDATAOFF	0xffffU
-typedef uint		xfs_dir2_data_aoff_t;	/* argument form */
-
-/*
- * Directory block number (logical dirblk in file)
- */
-typedef	__uint32_t	xfs_dir2_db_t;
-
-/*
- * Byte offset in a directory.
- */
-typedef	xfs_off_t	xfs_dir2_off_t;
-
 extern struct xfs_name	xfs_name_dotdot;
 
 /*
@@ -86,21 +51,10 @@ extern int xfs_dir_replace(struct xfs_trans *tp, struct xfs_inode *dp,
 				struct xfs_bmap_free *flist, xfs_extlen_t tot);
 extern int xfs_dir_canenter(struct xfs_trans *tp, struct xfs_inode *dp,
 				struct xfs_name *name, uint resblks);
-extern int xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino);
 
 /*
- * Utility routines for v2 directories.
+ * Direct call from the bmap code, bypassing the generic directory layer.
  */
-extern int xfs_dir2_grow_inode(struct xfs_da_args *args, int space,
-				xfs_dir2_db_t *dbp);
-extern int xfs_dir2_isblock(struct xfs_trans *tp, struct xfs_inode *dp,
-				int *vp);
-extern int xfs_dir2_isleaf(struct xfs_trans *tp, struct xfs_inode *dp,
-				int *vp);
-extern int xfs_dir2_shrink_inode(struct xfs_da_args *args, xfs_dir2_db_t db,
-				struct xfs_dabuf *bp);
-
-extern int xfs_dir_cilookup_result(struct xfs_da_args *args,
-				const unsigned char *name, int len);
+extern int xfs_dir2_sf_to_block(struct xfs_da_args *args);
 
 #endif	/* __XFS_DIR2_H__ */
diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index 70fb0cb6bd6..9245e029b8e 100644
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -23,17 +23,14 @@
 #include "xfs_trans.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
-#include "xfs_dir2.h"
 #include "xfs_mount.h"
 #include "xfs_da_btree.h"
 #include "xfs_bmap_btree.h"
-#include "xfs_dir2_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
-#include "xfs_dir2_data.h"
-#include "xfs_dir2_leaf.h"
-#include "xfs_dir2_block.h"
+#include "xfs_dir2_format.h"
+#include "xfs_dir2_priv.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
 
diff --git a/fs/xfs/xfs_dir2_block.h b/fs/xfs/xfs_dir2_block.h
deleted file mode 100644
index de59677e38b..00000000000
--- a/fs/xfs/xfs_dir2_block.h
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
- * All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it would be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write the Free Software Foundation,
- * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- */
-#ifndef __XFS_DIR2_BLOCK_H__
-#define	__XFS_DIR2_BLOCK_H__
-
-/*
- * Directory version 2, single block format structures.
- *
- * The single block format looks like the following drawing on disk:
- *
- *    +-------------------------------------------------+
- *    | xfs_dir2_data_hdr_t                             |
- *    +-------------------------------------------------+
- *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
- *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
- *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
- *    | ...                                             |
- *    +-------------------------------------------------+
- *    | unused space                                    |
- *    +-------------------------------------------------+
- *    | ...                                             |
- *    | xfs_dir2_leaf_entry_t                           |
- *    | xfs_dir2_leaf_entry_t                           |
- *    +-------------------------------------------------+
- *    | xfs_dir2_block_tail_t                           |
- *    +-------------------------------------------------+
- *
- * As all the entries are variable size structures the accessors in this
- * file and xfs_dir2_data.h should be used to iterate over them.
- */
-struct uio;
-struct xfs_dabuf;
-struct xfs_da_args;
-struct xfs_dir2_data_hdr;
-struct xfs_dir2_leaf_entry;
-struct xfs_inode;
-struct xfs_mount;
-struct xfs_trans;
-
-#define	XFS_DIR2_BLOCK_MAGIC	0x58443242	/* XD2B: for one block dirs */
-
-typedef struct xfs_dir2_block_tail {
-	__be32		count;			/* count of leaf entries */
-	__be32		stale;			/* count of stale lf entries */
-} xfs_dir2_block_tail_t;
-
-/*
- * Pointer to the leaf header embedded in a data block (1-block format)
- */
-static inline xfs_dir2_block_tail_t *
-xfs_dir2_block_tail_p(struct xfs_mount *mp, xfs_dir2_data_hdr_t *hdr)
-{
-	return ((xfs_dir2_block_tail_t *)((char *)hdr + mp->m_dirblksize)) - 1;
-}
-
-/*
- * Pointer to the leaf entries embedded in a data block (1-block format)
- */
-static inline struct xfs_dir2_leaf_entry *
-xfs_dir2_block_leaf_p(xfs_dir2_block_tail_t *btp)
-{
-	return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
-}
-
-/*
- * Function declarations.
- */
-extern int xfs_dir2_block_addname(struct xfs_da_args *args);
-extern int xfs_dir2_block_getdents(struct xfs_inode *dp, void *dirent,
-				   xfs_off_t *offset, filldir_t filldir);
-extern int xfs_dir2_block_lookup(struct xfs_da_args *args);
-extern int xfs_dir2_block_removename(struct xfs_da_args *args);
-extern int xfs_dir2_block_replace(struct xfs_da_args *args);
-extern int xfs_dir2_leaf_to_block(struct xfs_da_args *args,
-				  struct xfs_dabuf *lbp, struct xfs_dabuf *dbp);
-extern int xfs_dir2_sf_to_block(struct xfs_da_args *args);
-
-#endif	/* __XFS_DIR2_BLOCK_H__ */
diff --git a/fs/xfs/xfs_dir2_data.c b/fs/xfs/xfs_dir2_data.c
index 32dca4c531a..5bbe2a8a023 100644
--- a/fs/xfs/xfs_dir2_data.c
+++ b/fs/xfs/xfs_dir2_data.c
@@ -23,16 +23,13 @@
 #include "xfs_trans.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
-#include "xfs_dir2.h"
 #include "xfs_mount.h"
 #include "xfs_da_btree.h"
 #include "xfs_bmap_btree.h"
-#include "xfs_dir2_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
-#include "xfs_dir2_data.h"
-#include "xfs_dir2_leaf.h"
-#include "xfs_dir2_block.h"
+#include "xfs_dir2_format.h"
+#include "xfs_dir2_priv.h"
 #include "xfs_error.h"
 
 STATIC xfs_dir2_data_free_t *
diff --git a/fs/xfs/xfs_dir2_data.h b/fs/xfs/xfs_dir2_data.h
deleted file mode 100644
index c50512584eb..00000000000
--- a/fs/xfs/xfs_dir2_data.h
+++ /dev/null
@@ -1,182 +0,0 @@
-/*
- * Copyright (c) 2000,2005 Silicon Graphics, Inc.
- * All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it would be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write the Free Software Foundation,
- * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- */
-#ifndef __XFS_DIR2_DATA_H__
-#define	__XFS_DIR2_DATA_H__
-
-/*
- * Directory format 2, data block structures.
- *
- * A pure data block looks like the following drawing on disk:
- *
- *    +-------------------------------------------------+
- *    | xfs_dir2_data_hdr_t                             |
- *    +-------------------------------------------------+
- *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
- *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
- *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
- *    | ...                                             |
- *    +-------------------------------------------------+
- *    | unused space                                    |
- *    +-------------------------------------------------+
- *
- * As all the entries are variable size structures the accessors in this
- * file should be used to iterate over them.
- */
-
-struct xfs_dabuf;
-struct xfs_da_args;
-struct xfs_inode;
-struct xfs_trans;
-
-/*
- * Constants.
- */
-#define	XFS_DIR2_DATA_MAGIC	0x58443244	/* XD2D: for multiblock dirs */
-#define	XFS_DIR2_DATA_ALIGN_LOG	3		/* i.e., 8 bytes */
-#define	XFS_DIR2_DATA_ALIGN	(1 << XFS_DIR2_DATA_ALIGN_LOG)
-#define	XFS_DIR2_DATA_FREE_TAG	0xffff
-#define	XFS_DIR2_DATA_FD_COUNT	3
-
-/*
- * Directory address space divided into sections,
- * spaces separated by 32GB.
- */
-#define	XFS_DIR2_SPACE_SIZE	(1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
-#define	XFS_DIR2_DATA_SPACE	0
-#define	XFS_DIR2_DATA_OFFSET	(XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
-#define	XFS_DIR2_DATA_FIRSTDB(mp)	\
-	xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
-
-/*
- * Offsets of . and .. in data space (always block 0)
- */
-#define	XFS_DIR2_DATA_DOT_OFFSET	\
-	((xfs_dir2_data_aoff_t)sizeof(xfs_dir2_data_hdr_t))
-#define	XFS_DIR2_DATA_DOTDOT_OFFSET	\
-	(XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
-#define	XFS_DIR2_DATA_FIRST_OFFSET		\
-	(XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))
-
-/*
- * Structures.
- */
-
-/*
- * Describe a free area in the data block.
- * The freespace will be formatted as a xfs_dir2_data_unused_t.
- */
-typedef struct xfs_dir2_data_free {
-	__be16			offset;		/* start of freespace */
-	__be16			length;		/* length of freespace */
-} xfs_dir2_data_free_t;
-
-/*
- * Header for the data blocks.
- * Always at the beginning of a directory-sized block.
- * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
- */
-typedef struct xfs_dir2_data_hdr {
-	__be32			magic;		/* XFS_DIR2_DATA_MAGIC */
-						/* or XFS_DIR2_BLOCK_MAGIC */
-	xfs_dir2_data_free_t	bestfree[XFS_DIR2_DATA_FD_COUNT];
-} xfs_dir2_data_hdr_t;
-
-/*
- * Active entry in a data block.  Aligned to 8 bytes.
- *
- * After the variable length name field there is a 2 byte tag field, which
- * can be accessed using xfs_dir2_data_entry_tag_p.
- */
-typedef struct xfs_dir2_data_entry {
-	__be64			inumber;	/* inode number */
-	__u8			namelen;	/* name length */
-	__u8			name[];		/* name bytes, no null */
-     /*	__be16                  tag; */		/* starting offset of us */
-} xfs_dir2_data_entry_t;
-
-/*
- * Unused entry in a data block.  Aligned to 8 bytes.
- * Tag appears as the last 2 bytes.
- */
-typedef struct xfs_dir2_data_unused {
-	__be16			freetag;	/* XFS_DIR2_DATA_FREE_TAG */
-	__be16			length;		/* total free length */
-						/* variable offset */
-	__be16			tag;		/* starting offset of us */
-} xfs_dir2_data_unused_t;
-
-/*
- * Size of a data entry.
- */
-static inline int xfs_dir2_data_entsize(int n)
-{
-	return (int)roundup(offsetof(xfs_dir2_data_entry_t, name[0]) + (n) + \
-		 (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
-}
-
-/*
- * Pointer to an entry's tag word.
- */
-static inline __be16 *
-xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
-{
-	return (__be16 *)((char *)dep +
-		xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
-}
-
-/*
- * Pointer to a freespace's tag word.
- */
-static inline __be16 *
-xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
-{
-	return (__be16 *)((char *)dup +
-			be16_to_cpu(dup->length) - sizeof(__be16));
-}
-
-/*
- * Function declarations.
- */
-#ifdef DEBUG
-extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_dabuf *bp);
-#else
-#define	xfs_dir2_data_check(dp,bp)
-#endif
-extern xfs_dir2_data_free_t *xfs_dir2_data_freeinsert(xfs_dir2_data_hdr_t *hdr,
-				xfs_dir2_data_unused_t *dup, int *loghead);
-extern void xfs_dir2_data_freescan(struct xfs_mount *mp,
-				xfs_dir2_data_hdr_t *hdr, int *loghead);
-extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
-				struct xfs_dabuf **bpp);
-extern void xfs_dir2_data_log_entry(struct xfs_trans *tp, struct xfs_dabuf *bp,
-				xfs_dir2_data_entry_t *dep);
-extern void xfs_dir2_data_log_header(struct xfs_trans *tp,
-				struct xfs_dabuf *bp);
-extern void xfs_dir2_data_log_unused(struct xfs_trans *tp, struct xfs_dabuf *bp,
-				xfs_dir2_data_unused_t *dup);
-extern void xfs_dir2_data_make_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
-				xfs_dir2_data_aoff_t offset,
-				xfs_dir2_data_aoff_t len, int *needlogp,
-				int *needscanp);
-extern void xfs_dir2_data_use_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
-			       xfs_dir2_data_unused_t *dup,
-			       xfs_dir2_data_aoff_t offset,
-			       xfs_dir2_data_aoff_t len, int *needlogp,
-			       int *needscanp);
-
-#endif	/* __XFS_DIR2_DATA_H__ */
diff --git a/fs/xfs/xfs_dir2_format.h b/fs/xfs/xfs_dir2_format.h
new file mode 100644
index 00000000000..c3c4839eebd
--- /dev/null
+++ b/fs/xfs/xfs_dir2_format.h
@@ -0,0 +1,595 @@
+/*
+ * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef __XFS_DIR2_FORMAT_H__
+#define __XFS_DIR2_FORMAT_H__
+
+/*
+ * Directory version 2.
+ *
+ * There are 4 possible formats:
+ *  - shortform - embedded into the inode
+ *  - single block - data with embedded leaf at the end
+ *  - multiple data blocks, single leaf+freeindex block
+ *  - data blocks, node and leaf blocks (btree), freeindex blocks
+ *
+ * Note: many node blocks structures and constants are shared with the attr
+ * code and defined in xfs_da_btree.h.
+ */
+
+#define	XFS_DIR2_BLOCK_MAGIC	0x58443242	/* XD2B: single block dirs */
+#define	XFS_DIR2_DATA_MAGIC	0x58443244	/* XD2D: multiblock dirs */
+#define	XFS_DIR2_FREE_MAGIC	0x58443246	/* XD2F: free index blocks */
+
+/*
+ * Byte offset in data block and shortform entry.
+ */
+typedef	__uint16_t	xfs_dir2_data_off_t;
+#define	NULLDATAOFF	0xffffU
+typedef uint		xfs_dir2_data_aoff_t;	/* argument form */
+
+/*
+ * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
+ * Only need 16 bits, this is the byte offset into the single block form.
+ */
+typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
+
+/*
+ * Offset in data space of a data entry.
+ */
+typedef	__uint32_t	xfs_dir2_dataptr_t;
+#define	XFS_DIR2_MAX_DATAPTR	((xfs_dir2_dataptr_t)0xffffffff)
+#define	XFS_DIR2_NULL_DATAPTR	((xfs_dir2_dataptr_t)0)
+
+/*
+ * Byte offset in a directory.
+ */
+typedef	xfs_off_t	xfs_dir2_off_t;
+
+/*
+ * Directory block number (logical dirblk in file)
+ */
+typedef	__uint32_t	xfs_dir2_db_t;
+
+/*
+ * Inode number stored as 8 8-bit values.
+ */
+typedef	struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
+
+/*
+ * Inode number stored as 4 8-bit values.
+ * Works a lot of the time, when all the inode numbers in a directory
+ * fit in 32 bits.
+ */
+typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
+
+typedef union {
+	xfs_dir2_ino8_t	i8;
+	xfs_dir2_ino4_t	i4;
+} xfs_dir2_inou_t;
+#define	XFS_DIR2_MAX_SHORT_INUM	((xfs_ino_t)0xffffffffULL)
+
+/*
+ * Directory layout when stored internal to an inode.
+ *
+ * Small directories are packed as tightly as possible so as to fit into the
+ * literal area of the inode.  These "shortform" directories consist of a
+ * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
+ * structures.  Due the different inode number storage size and the variable
+ * length name field in the xfs_dir2_sf_entry all these structure are
+ * variable length, and the accessors in this file should be used to iterate
+ * over them.
+ */
+typedef struct xfs_dir2_sf_hdr {
+	__uint8_t		count;		/* count of entries */
+	__uint8_t		i8count;	/* count of 8-byte inode #s */
+	xfs_dir2_inou_t		parent;		/* parent dir inode number */
+} __arch_pack xfs_dir2_sf_hdr_t;
+
+typedef struct xfs_dir2_sf_entry {
+	__u8			namelen;	/* actual name length */
+	xfs_dir2_sf_off_t	offset;		/* saved offset */
+	__u8			name[];		/* name, variable size */
+	/*
+	 * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
+	 * variable offset after the name.
+	 */
+} __arch_pack xfs_dir2_sf_entry_t;
+
+static inline int xfs_dir2_sf_hdr_size(int i8count)
+{
+	return sizeof(struct xfs_dir2_sf_hdr) -
+		(i8count == 0) *
+		(sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t));
+}
+
+static inline xfs_dir2_data_aoff_t
+xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
+{
+	return get_unaligned_be16(&sfep->offset.i);
+}
+
+static inline void
+xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
+{
+	put_unaligned_be16(off, &sfep->offset.i);
+}
+
+static inline int
+xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len)
+{
+	return sizeof(struct xfs_dir2_sf_entry) +	/* namelen + offset */
+		len +					/* name */
+		(hdr->i8count ?				/* ino */
+		 sizeof(xfs_dir2_ino8_t) :
+		 sizeof(xfs_dir2_ino4_t));
+}
+
+static inline struct xfs_dir2_sf_entry *
+xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
+{
+	return (struct xfs_dir2_sf_entry *)
+		((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
+}
+
+static inline struct xfs_dir2_sf_entry *
+xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
+		struct xfs_dir2_sf_entry *sfep)
+{
+	return (struct xfs_dir2_sf_entry *)
+		((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
+}
+
+
+/*
+ * Data block structures.
+ *
+ * A pure data block looks like the following drawing on disk:
+ *
+ *    +-------------------------------------------------+
+ *    | xfs_dir2_data_hdr_t                             |
+ *    +-------------------------------------------------+
+ *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
+ *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
+ *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
+ *    | ...                                             |
+ *    +-------------------------------------------------+
+ *    | unused space                                    |
+ *    +-------------------------------------------------+
+ *
+ * As all the entries are variable size structures the accessors below should
+ * be used to iterate over them.
+ *
+ * In addition to the pure data blocks for the data and node formats,
+ * most structures are also used for the combined data/freespace "block"
+ * format below.
+ */
+
+#define	XFS_DIR2_DATA_ALIGN_LOG	3		/* i.e., 8 bytes */
+#define	XFS_DIR2_DATA_ALIGN	(1 << XFS_DIR2_DATA_ALIGN_LOG)
+#define	XFS_DIR2_DATA_FREE_TAG	0xffff
+#define	XFS_DIR2_DATA_FD_COUNT	3
+
+/*
+ * Directory address space divided into sections,
+ * spaces separated by 32GB.
+ */
+#define	XFS_DIR2_SPACE_SIZE	(1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
+#define	XFS_DIR2_DATA_SPACE	0
+#define	XFS_DIR2_DATA_OFFSET	(XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
+#define	XFS_DIR2_DATA_FIRSTDB(mp)	\
+	xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
+
+/*
+ * Offsets of . and .. in data space (always block 0)
+ */
+#define	XFS_DIR2_DATA_DOT_OFFSET	\
+	((xfs_dir2_data_aoff_t)sizeof(struct xfs_dir2_data_hdr))
+#define	XFS_DIR2_DATA_DOTDOT_OFFSET	\
+	(XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
+#define	XFS_DIR2_DATA_FIRST_OFFSET		\
+	(XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))
+
+/*
+ * Describe a free area in the data block.
+ *
+ * The freespace will be formatted as a xfs_dir2_data_unused_t.
+ */
+typedef struct xfs_dir2_data_free {
+	__be16			offset;		/* start of freespace */
+	__be16			length;		/* length of freespace */
+} xfs_dir2_data_free_t;
+
+/*
+ * Header for the data blocks.
+ *
+ * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
+ */
+typedef struct xfs_dir2_data_hdr {
+	__be32			magic;		/* XFS_DIR2_DATA_MAGIC or */
+						/* XFS_DIR2_BLOCK_MAGIC */
+	xfs_dir2_data_free_t	bestfree[XFS_DIR2_DATA_FD_COUNT];
+} xfs_dir2_data_hdr_t;
+
+/*
+ * Active entry in a data block.
+ *
+ * Aligned to 8 bytes.  After the variable length name field there is a
+ * 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p.
+ */
+typedef struct xfs_dir2_data_entry {
+	__be64			inumber;	/* inode number */
+	__u8			namelen;	/* name length */
+	__u8			name[];		/* name bytes, no null */
+     /*	__be16                  tag; */		/* starting offset of us */
+} xfs_dir2_data_entry_t;
+
+/*
+ * Unused entry in a data block.
+ *
+ * Aligned to 8 bytes.  Tag appears as the last 2 bytes and must be accessed
+ * using xfs_dir2_data_unused_tag_p.
+ */
+typedef struct xfs_dir2_data_unused {
+	__be16			freetag;	/* XFS_DIR2_DATA_FREE_TAG */
+	__be16			length;		/* total free length */
+						/* variable offset */
+	__be16			tag;		/* starting offset of us */
+} xfs_dir2_data_unused_t;
+
+/*
+ * Size of a data entry.
+ */
+static inline int xfs_dir2_data_entsize(int n)
+{
+	return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n +
+		 (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
+}
+
+/*
+ * Pointer to an entry's tag word.
+ */
+static inline __be16 *
+xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep)
+{
+	return (__be16 *)((char *)dep +
+		xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
+}
+
+/*
+ * Pointer to a freespace's tag word.
+ */
+static inline __be16 *
+xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
+{
+	return (__be16 *)((char *)dup +
+			be16_to_cpu(dup->length) - sizeof(__be16));
+}
+
+/*
+ * Leaf block structures.
+ *
+ * A pure leaf block looks like the following drawing on disk:
+ *
+ *    +---------------------------+
+ *    | xfs_dir2_leaf_hdr_t       |
+ *    +---------------------------+
+ *    | xfs_dir2_leaf_entry_t     |
+ *    | xfs_dir2_leaf_entry_t     |
+ *    | xfs_dir2_leaf_entry_t     |
+ *    | xfs_dir2_leaf_entry_t     |
+ *    | ...                       |
+ *    +---------------------------+
+ *    | xfs_dir2_data_off_t       |
+ *    | xfs_dir2_data_off_t       |
+ *    | xfs_dir2_data_off_t       |
+ *    | ...                       |
+ *    +---------------------------+
+ *    | xfs_dir2_leaf_tail_t      |
+ *    +---------------------------+
+ *
+ * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
+ * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
+ * for directories with separate leaf nodes and free space blocks
+ * (magic = XFS_DIR2_LEAFN_MAGIC).
+ *
+ * As all the entries are variable size structures the accessors below should
+ * be used to iterate over them.
+ */
+
+/*
+ * Offset of the leaf/node space.  First block in this space
+ * is the btree root.
+ */
+#define	XFS_DIR2_LEAF_SPACE	1
+#define	XFS_DIR2_LEAF_OFFSET	(XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
+#define	XFS_DIR2_LEAF_FIRSTDB(mp)	\
+	xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)
+
+/*
+ * Leaf block header.
+ */
+typedef struct xfs_dir2_leaf_hdr {
+	xfs_da_blkinfo_t	info;		/* header for da routines */
+	__be16			count;		/* count of entries */
+	__be16			stale;		/* count of stale entries */
+} xfs_dir2_leaf_hdr_t;
+
+/*
+ * Leaf block entry.
+ */
+typedef struct xfs_dir2_leaf_entry {
+	__be32			hashval;	/* hash value of name */
+	__be32			address;	/* address of data entry */
+} xfs_dir2_leaf_entry_t;
+
+/*
+ * Leaf block tail.
+ */
+typedef struct xfs_dir2_leaf_tail {
+	__be32			bestcount;
+} xfs_dir2_leaf_tail_t;
+
+/*
+ * Leaf block.
+ */
+typedef struct xfs_dir2_leaf {
+	xfs_dir2_leaf_hdr_t	hdr;		/* leaf header */
+	xfs_dir2_leaf_entry_t	ents[];		/* entries */
+} xfs_dir2_leaf_t;
+
+/*
+ * DB blocks here are logical directory block numbers, not filesystem blocks.
+ */
+
+static inline int xfs_dir2_max_leaf_ents(struct xfs_mount *mp)
+{
+	return (mp->m_dirblksize - (uint)sizeof(struct xfs_dir2_leaf_hdr)) /
+		(uint)sizeof(struct xfs_dir2_leaf_entry);
+}
+
+/*
+ * Get address of the bestcount field in the single-leaf block.
+ */
+static inline struct xfs_dir2_leaf_tail *
+xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
+{
+	return (struct xfs_dir2_leaf_tail *)
+		((char *)lp + mp->m_dirblksize -
+		  sizeof(struct xfs_dir2_leaf_tail));
+}
+
+/*
+ * Get address of the bests array in the single-leaf block.
+ */
+static inline __be16 *
+xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
+{
+	return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
+}
+
+/*
+ * Convert dataptr to byte in file space
+ */
+static inline xfs_dir2_off_t
+xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
+{
+	return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
+}
+
+/*
+ * Convert byte in file space to dataptr.  It had better be aligned.
+ */
+static inline xfs_dir2_dataptr_t
+xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
+{
+	return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
+}
+
+/*
+ * Convert byte in space to (DB) block
+ */
+static inline xfs_dir2_db_t
+xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
+{
+	return (xfs_dir2_db_t)
+		(by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
+}
+
+/*
+ * Convert dataptr to a block number
+ */
+static inline xfs_dir2_db_t
+xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
+{
+	return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
+}
+
+/*
+ * Convert byte in space to offset in a block
+ */
+static inline xfs_dir2_data_aoff_t
+xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
+{
+	return (xfs_dir2_data_aoff_t)(by &
+		((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
+}
+
+/*
+ * Convert dataptr to a byte offset in a block
+ */
+static inline xfs_dir2_data_aoff_t
+xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
+{
+	return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
+}
+
+/*
+ * Convert block and offset to byte in space
+ */
+static inline xfs_dir2_off_t
+xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
+			xfs_dir2_data_aoff_t o)
+{
+	return ((xfs_dir2_off_t)db <<
+		(mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
+}
+
+/*
+ * Convert block (DB) to block (dablk)
+ */
+static inline xfs_dablk_t
+xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
+{
+	return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
+}
+
+/*
+ * Convert byte in space to (DA) block
+ */
+static inline xfs_dablk_t
+xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
+{
+	return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));