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Consolidate btree block handling for xfs_db

Currently xfs_db has five different implementations for poking at btree
blocks, even duplicating code for btree blocks with entirely identical
layout (bmapbta vs bmapbtd and bno vs cnt).  Merge all these into
a single implementation that uses a table of btree characteristics keyed
of their magic number.

There's probably a way to further consolidate the magic arrays for the
different types, but I don't quite understand xfs_db's table driven
command parser for that.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Merge of master-melb:xfs-cmds:32248a by kenmcd.

  Consolidate btree block handling for xfs_db

/*
 * 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
 */

#include <xfs/libxfs.h>
#include "type.h"
#include "faddr.h"
#include "fprint.h"
#include "field.h"
#include "btblock.h"
#include "print.h"
#include "bit.h"
#include "init.h"


/*
 * Definition of the possible btree block layouts.
 */
struct xfs_db_btree {
	size_t			block_len;
	size_t			key_len;
	size_t			rec_len;
	size_t			ptr_len;
} btrees[] = {
	[/*0x424d415*/0] = { /* BMAP */
		sizeof(struct xfs_btree_lblock),
		sizeof(xfs_bmbt_key_t),
		sizeof(xfs_bmbt_rec_t),
		sizeof(__be64),
	},
	[/*0x4142544*/2] = { /* ABTB */
		sizeof(struct xfs_btree_sblock),
		sizeof(xfs_alloc_key_t),
		sizeof(xfs_alloc_rec_t),
		sizeof(__be32),
	},
	[/*0x4142544*/3] = { /* ABTC */
		sizeof(struct xfs_btree_sblock),
		sizeof(xfs_alloc_key_t),
		sizeof(xfs_alloc_rec_t),
		sizeof(__be32),
	},
	[/*0x4941425*/4] = { /* IABT */
		sizeof(struct xfs_btree_sblock),
		sizeof(xfs_inobt_key_t),
		sizeof(xfs_inobt_rec_t),
		sizeof(__be32),
	},
};

/*
 * Find the right block defintion for a given ondisk block.
 *
 * We use the least significant bit of the magic number as index into
 * the array of block defintions.
 */
#define block_to_bt(bb) \
	(&btrees[be32_to_cpu((bb)->bb_magic) & 0xf])

/* calculate max records.  Only for non-leaves. */
static int
btblock_maxrecs(struct xfs_db_btree *bt, int blocksize)
{
	blocksize -= bt->block_len;

	return blocksize / (bt->key_len + bt->ptr_len);
}

/*
 * Get the number of keys in a btree block.
 *
 * Note: can also be used to get the number of ptrs because there are
 * always the same number of keys and ptrs in a block.
 */
static int
btblock_key_count(
	void			*obj,
	int			startoff)
{
	struct xfs_btree_block	*block = obj;

	ASSERT(startoff == 0);

	if (block->bb_level == 0)
		return 0;
	return be16_to_cpu(block->bb_numrecs);
}

/*
 * Get the number of keys in a btree block.
 */
static int
btblock_rec_count(
	void			*obj,
	int			startoff)
{
	struct xfs_btree_block	*block = obj;

	ASSERT(startoff == 0);

	if (block->bb_level != 0)
		return 0;
	return be16_to_cpu(block->bb_numrecs);
}

/*
 * Get the offset of the key at idx in a btree block.
 */
static int
btblock_key_offset(
	void			*obj,
	int			startoff,
	int			idx)
{
	struct xfs_btree_block	*block = obj;
	struct xfs_db_btree	*bt = block_to_bt(block);
	int			offset;

	ASSERT(startoff == 0);
	ASSERT(block->bb_level != 0);

	offset = bt->block_len + (idx - 1) * bt->key_len;
	return bitize(offset);
}

/*
 * Get the offset of the ptr at idx in a btree block.
 */
static int
btblock_ptr_offset(
	void			*obj,
	int			startoff,
	int			idx)
{
	struct xfs_btree_block	*block = obj;
	struct xfs_db_btree	*bt = block_to_bt(block);
	int			offset;
	int			maxrecs;

	ASSERT(startoff == 0);
	ASSERT(block->bb_level != 0);

	maxrecs = btblock_maxrecs(bt, mp->m_sb.sb_blocksize);
	offset = bt->block_len +
			maxrecs * bt->key_len +
			(idx - 1) * bt->ptr_len;

	return bitize(offset);
}

/*
 * Get the offset of the record at idx in a btree block.
 */
static int
btblock_rec_offset(
	void			*obj,
	int			startoff,
	int			idx)
{
	struct xfs_btree_block	*block = obj;
	struct xfs_db_btree	*bt = block_to_bt(block);
	int			offset;

	ASSERT(startoff == 0);
	ASSERT(block->bb_level == 0);

	offset = bt->block_len + (idx - 1) * bt->rec_len;
	return bitize(offset);
}

/*
 * Get the size of a btree block.
 */
int
btblock_size(
	void	*obj,
	int	startoff,
	int	idx)
{
	return bitize(mp->m_sb.sb_blocksize);
}


/*
 * Bmap btree.
 */

const field_t	bmapbta_hfld[] = {
	{ "", FLDT_BMAPBTA, OI(0), C1, 0, TYP_NONE },
	{ NULL }
};
const field_t	bmapbtd_hfld[] = {
	{ "", FLDT_BMAPBTD, OI(0), C1, 0, TYP_NONE },
	{ NULL }
};

#define	OFF(f)	bitize(offsetof(xfs_bmbt_block_t, bb_ ## f))
const field_t	bmapbta_flds[] = {
	{ "magic", FLDT_UINT32X, OI(OFF(magic)), C1, 0, TYP_NONE },
	{ "level", FLDT_UINT16D, OI(OFF(level)), C1, 0, TYP_NONE },
	{ "numrecs", FLDT_UINT16D, OI(OFF(numrecs)), C1, 0, TYP_NONE },
	{ "leftsib", FLDT_DFSBNO, OI(OFF(leftsib)), C1, 0, TYP_BMAPBTA },
	{ "rightsib", FLDT_DFSBNO, OI(OFF(rightsib)), C1, 0, TYP_BMAPBTA },
	{ "recs", FLDT_BMAPBTAREC, btblock_rec_offset, btblock_rec_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "keys", FLDT_BMAPBTAKEY, btblock_key_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "ptrs", FLDT_BMAPBTAPTR, btblock_ptr_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_BMAPBTA },
	{ NULL }
};
const field_t	bmapbtd_flds[] = {
	{ "magic", FLDT_UINT32X, OI(OFF(magic)), C1, 0, TYP_NONE },
	{ "level", FLDT_UINT16D, OI(OFF(level)), C1, 0, TYP_NONE },
	{ "numrecs", FLDT_UINT16D, OI(OFF(numrecs)), C1, 0, TYP_NONE },
	{ "leftsib", FLDT_DFSBNO, OI(OFF(leftsib)), C1, 0, TYP_BMAPBTD },
	{ "rightsib", FLDT_DFSBNO, OI(OFF(rightsib)), C1, 0, TYP_BMAPBTD },
	{ "recs", FLDT_BMAPBTDREC, btblock_rec_offset, btblock_rec_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "keys", FLDT_BMAPBTDKEY, btblock_key_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "ptrs", FLDT_BMAPBTDPTR, btblock_ptr_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_BMAPBTD },
	{ NULL }
};
#undef OFF

#define	KOFF(f)	bitize(offsetof(xfs_bmbt_key_t, br_ ## f))
const field_t	bmapbta_key_flds[] = {
	{ "startoff", FLDT_DFILOFFA, OI(KOFF(startoff)), C1, 0, TYP_ATTR },
	{ NULL }
};
const field_t	bmapbtd_key_flds[] = {
	{ "startoff", FLDT_DFILOFFD, OI(KOFF(startoff)), C1, 0, TYP_INODATA },
	{ NULL }
};
#undef KOFF

#ifndef XFS_NATIVE_HOST

#define BMBT_EXNTFLAG_BITOFF	0
#define BMBT_STARTOFF_BITOFF	(BMBT_EXNTFLAG_BITOFF + BMBT_EXNTFLAG_BITLEN)
#define BMBT_STARTBLOCK_BITOFF	(BMBT_STARTOFF_BITOFF + BMBT_STARTOFF_BITLEN)
#define BMBT_BLOCKCOUNT_BITOFF	\
	(BMBT_STARTBLOCK_BITOFF + BMBT_STARTBLOCK_BITLEN)

#else

#define BMBT_EXNTFLAG_BITOFF	63
#define BMBT_STARTOFF_BITOFF	(BMBT_EXNTFLAG_BITOFF - BMBT_STARTOFF_BITLEN)
#define BMBT_STARTBLOCK_BITOFF	85 /* 128 - 43 (other 9 is in first word) */
#define BMBT_BLOCKCOUNT_BITOFF	64 /* Start of second 64 bit container */

#endif /* XFS_NATIVE_HOST */

const field_t	bmapbta_rec_flds[] = {
	{ "startoff", FLDT_CFILEOFFA, OI(BMBT_STARTOFF_BITOFF), C1, 0,
	  TYP_ATTR },
	{ "startblock", FLDT_CFSBLOCK, OI(BMBT_STARTBLOCK_BITOFF), C1, 0,
	  TYP_ATTR },
	{ "blockcount", FLDT_CEXTLEN, OI(BMBT_BLOCKCOUNT_BITOFF), C1, 0,
	  TYP_NONE },
	{ "extentflag", FLDT_CEXTFLG, OI(BMBT_EXNTFLAG_BITOFF), C1, 0,
	  TYP_NONE },
	{ NULL }
};
const field_t	bmapbtd_rec_flds[] = {
	{ "startoff", FLDT_CFILEOFFD, OI(BMBT_STARTOFF_BITOFF), C1, 0,
	  TYP_INODATA },
	{ "startblock", FLDT_CFSBLOCK, OI(BMBT_STARTBLOCK_BITOFF), C1, 0,
	  TYP_INODATA },
	{ "blockcount", FLDT_CEXTLEN, OI(BMBT_BLOCKCOUNT_BITOFF), C1, 0,
	  TYP_NONE },
	{ "extentflag", FLDT_CEXTFLG, OI(BMBT_EXNTFLAG_BITOFF), C1, 0,
	  TYP_NONE },
	{ NULL }
};


/*
 * Inode allocation btree.
 */

const field_t	inobt_hfld[] = {
	{ "", FLDT_INOBT, OI(0), C1, 0, TYP_NONE },
	{ NULL }
};

#define	OFF(f)	bitize(offsetof(struct xfs_btree_sblock, bb_ ## f))
const field_t	inobt_flds[] = {
	{ "magic", FLDT_UINT32X, OI(OFF(magic)), C1, 0, TYP_NONE },
	{ "level", FLDT_UINT16D, OI(OFF(level)), C1, 0, TYP_NONE },
	{ "numrecs", FLDT_UINT16D, OI(OFF(numrecs)), C1, 0, TYP_NONE },
	{ "leftsib", FLDT_AGBLOCK, OI(OFF(leftsib)), C1, 0, TYP_INOBT },
	{ "rightsib", FLDT_AGBLOCK, OI(OFF(rightsib)), C1, 0, TYP_INOBT },
	{ "recs", FLDT_INOBTREC, btblock_rec_offset, btblock_rec_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "keys", FLDT_INOBTKEY, btblock_key_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "ptrs", FLDT_INOBTPTR, btblock_ptr_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_INOBT },
	{ NULL }
};
#undef OFF

#define	KOFF(f)	bitize(offsetof(xfs_inobt_key_t, ir_ ## f))
const field_t	inobt_key_flds[] = {
	{ "startino", FLDT_AGINO, OI(KOFF(startino)), C1, 0, TYP_INODE },
	{ NULL }
};
#undef KOFF

#define	ROFF(f)	bitize(offsetof(xfs_inobt_rec_t, ir_ ## f))
const field_t	inobt_rec_flds[] = {
	{ "startino", FLDT_AGINO, OI(ROFF(startino)), C1, 0, TYP_INODE },
	{ "freecount", FLDT_INT32D, OI(ROFF(freecount)), C1, 0, TYP_NONE },
	{ "free", FLDT_INOFREE, OI(ROFF(free)), C1, 0, TYP_NONE },
	{ NULL }
};
#undef ROFF


/*
 * Allocation btrees.
 */
const field_t	bnobt_hfld[] = {
	{ "", FLDT_BNOBT, OI(0), C1, 0, TYP_NONE },
	{ NULL }
};

#define	OFF(f)	bitize(offsetof(xfs_alloc_block_t, bb_ ## f))
const field_t	bnobt_flds[] = {
	{ "magic", FLDT_UINT32X, OI(OFF(magic)), C1, 0, TYP_NONE },
	{ "level", FLDT_UINT16D, OI(OFF(level)), C1, 0, TYP_NONE },
	{ "numrecs", FLDT_UINT16D, OI(OFF(numrecs)), C1, 0, TYP_NONE },
	{ "leftsib", FLDT_AGBLOCK, OI(OFF(leftsib)), C1, 0, TYP_BNOBT },
	{ "rightsib", FLDT_AGBLOCK, OI(OFF(rightsib)), C1, 0, TYP_BNOBT },
	{ "recs", FLDT_BNOBTREC, btblock_rec_offset, btblock_rec_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "keys", FLDT_BNOBTKEY, btblock_key_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "ptrs", FLDT_BNOBTPTR, btblock_ptr_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_BNOBT },
	{ NULL }
};
#undef OFF

#define	KOFF(f)	bitize(offsetof(xfs_alloc_key_t, ar_ ## f))
const field_t	bnobt_key_flds[] = {
	{ "startblock", FLDT_AGBLOCK, OI(KOFF(startblock)), C1, 0, TYP_DATA },
	{ "blockcount", FLDT_EXTLEN, OI(KOFF(blockcount)), C1, 0, TYP_NONE },
	{ NULL }
};
#undef KOFF

#define	ROFF(f)	bitize(offsetof(xfs_alloc_rec_t, ar_ ## f))
const field_t	bnobt_rec_flds[] = {
	{ "startblock", FLDT_AGBLOCK, OI(ROFF(startblock)), C1, 0, TYP_DATA },
	{ "blockcount", FLDT_EXTLEN, OI(ROFF(blockcount)), C1, 0, TYP_NONE },
	{ NULL }
};
#undef ROFF

const field_t	cntbt_hfld[] = {
	{ "", FLDT_CNTBT, OI(0), C1, 0, TYP_NONE },
	{ NULL }
};

#define	OFF(f)	bitize(offsetof(xfs_alloc_block_t, bb_ ## f))
const field_t	cntbt_flds[] = {
	{ "magic", FLDT_UINT32X, OI(OFF(magic)), C1, 0, TYP_NONE },
	{ "level", FLDT_UINT16D, OI(OFF(level)), C1, 0, TYP_NONE },
	{ "numrecs", FLDT_UINT16D, OI(OFF(numrecs)), C1, 0, TYP_NONE },
	{ "leftsib", FLDT_AGBLOCK, OI(OFF(leftsib)), C1, 0, TYP_CNTBT },
	{ "rightsib", FLDT_AGBLOCK, OI(OFF(rightsib)), C1, 0, TYP_CNTBT },
	{ "recs", FLDT_CNTBTREC, btblock_rec_offset, btblock_rec_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "keys", FLDT_CNTBTKEY, btblock_key_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_NONE },
	{ "ptrs", FLDT_CNTBTPTR, btblock_ptr_offset, btblock_key_count,
	  FLD_ARRAY|FLD_ABASE1|FLD_COUNT|FLD_OFFSET, TYP_CNTBT },
	{ NULL }
};
#undef OFF

#define	KOFF(f)	bitize(offsetof(xfs_alloc_key_t, ar_ ## f))
const field_t	cntbt_key_flds[] = {
	{ "blockcount", FLDT_EXTLEN, OI(KOFF(blockcount)), C1, 0, TYP_NONE },
	{ "startblock", FLDT_AGBLOCK, OI(KOFF(startblock)), C1, 0, TYP_DATA },
	{ NULL }
};
#undef KOFF

#define	ROFF(f)	bitize(offsetof(xfs_alloc_rec_t, ar_ ## f))
const field_t	cntbt_rec_flds[] = {
	{ "startblock", FLDT_AGBLOCK, OI(ROFF(startblock)), C1, 0, TYP_DATA },
	{ "blockcount", FLDT_EXTLEN, OI(ROFF(blockcount)), C1, 0, TYP_NONE },
	{ NULL }
};
#undef ROFF