xfs_btree.c

linux 内核源代码

/*
 * Copyright (c) 2000-2002,2005 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.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_error.h"

/*
 * Cursor allocation zone.
 */
kmem_zone_t	*xfs_btree_cur_zone;

/*
 * Btree magic numbers.
 */
const __uint32_t xfs_magics[XFS_BTNUM_MAX] =
{
	XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
};

/*
 * Prototypes for internal routines.
 */

/*
 * Checking routine: return maxrecs for the block.
 */
STATIC int				/* number of records fitting in block */
xfs_btree_maxrecs(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_block_t	*block);/* generic btree block pointer */

/*
 * Internal routines.
 */

/*
 * Retrieve the block pointer from the cursor at the given level.
 * This may be a bmap btree root or from a buffer.
 */
STATIC xfs_btree_block_t *			/* generic btree block pointer */
xfs_btree_get_block(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level in btree */
	struct xfs_buf		**bpp);	/* buffer containing the block */

/*
 * Checking routine: return maxrecs for the block.
 */
STATIC int				/* number of records fitting in block */
xfs_btree_maxrecs(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_block_t	*block)	/* generic btree block pointer */
{
	switch (cur->bc_btnum) {
	case XFS_BTNUM_BNO:
	case XFS_BTNUM_CNT:
		return (int)XFS_ALLOC_BLOCK_MAXRECS(
				be16_to_cpu(block->bb_h.bb_level), cur);
	case XFS_BTNUM_BMAP:
		return (int)XFS_BMAP_BLOCK_IMAXRECS(
				be16_to_cpu(block->bb_h.bb_level), cur);
	case XFS_BTNUM_INO:
		return (int)XFS_INOBT_BLOCK_MAXRECS(
				be16_to_cpu(block->bb_h.bb_level), cur);
	default:
		ASSERT(0);
		return 0;
	}
}

/*
 * External routines.
 */

#ifdef DEBUG
/*
 * Debug routine: check that block header is ok.
 */
void
xfs_btree_check_block(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_block_t	*block,	/* generic btree block pointer */
	int			level,	/* level of the btree block */
	xfs_buf_t		*bp)	/* buffer containing block, if any */
{
	if (XFS_BTREE_LONG_PTRS(cur->bc_btnum))
		xfs_btree_check_lblock(cur, (xfs_btree_lblock_t *)block, level,
			bp);
	else
		xfs_btree_check_sblock(cur, (xfs_btree_sblock_t *)block, level,
			bp);
}

/*
 * Debug routine: check that keys are in the right order.
 */
void
xfs_btree_check_key(
	xfs_btnum_t	btnum,		/* btree identifier */
	void		*ak1,		/* pointer to left (lower) key */
	void		*ak2)		/* pointer to right (higher) key */
{
	switch (btnum) {
	case XFS_BTNUM_BNO: {
		xfs_alloc_key_t	*k1;
		xfs_alloc_key_t	*k2;

		k1 = ak1;
		k2 = ak2;
		ASSERT(be32_to_cpu(k1->ar_startblock) < be32_to_cpu(k2->ar_startblock));
		break;
	    }
	case XFS_BTNUM_CNT: {
		xfs_alloc_key_t	*k1;
		xfs_alloc_key_t	*k2;

		k1 = ak1;
		k2 = ak2;
		ASSERT(be32_to_cpu(k1->ar_blockcount) < be32_to_cpu(k2->ar_blockcount) ||
		       (k1->ar_blockcount == k2->ar_blockcount &&
			be32_to_cpu(k1->ar_startblock) < be32_to_cpu(k2->ar_startblock)));
		break;
	    }
	case XFS_BTNUM_BMAP: {
		xfs_bmbt_key_t	*k1;
		xfs_bmbt_key_t	*k2;

		k1 = ak1;
		k2 = ak2;
		ASSERT(be64_to_cpu(k1->br_startoff) < be64_to_cpu(k2->br_startoff));
		break;
	    }
	case XFS_BTNUM_INO: {
		xfs_inobt_key_t	*k1;
		xfs_inobt_key_t	*k2;

		k1 = ak1;
		k2 = ak2;
		ASSERT(be32_to_cpu(k1->ir_startino) < be32_to_cpu(k2->ir_startino));
		break;
	    }
	default:
		ASSERT(0);
	}
}
#endif	/* DEBUG */

/*
 * Checking routine: check that long form block header is ok.
 */
/* ARGSUSED */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_lblock(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_lblock_t	*block,	/* btree long form block pointer */
	int			level,	/* level of the btree block */
	xfs_buf_t		*bp)	/* buffer for block, if any */
{
	int			lblock_ok; /* block passes checks */
	xfs_mount_t		*mp;	/* file system mount point */

	mp = cur->bc_mp;
	lblock_ok =
		be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
		be16_to_cpu(block->bb_level) == level &&
		be16_to_cpu(block->bb_numrecs) <=
			xfs_btree_maxrecs(cur, (xfs_btree_block_t *)block) &&
		block->bb_leftsib &&
		(be64_to_cpu(block->bb_leftsib) == NULLDFSBNO ||
		 XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_leftsib))) &&
		block->bb_rightsib &&
		(be64_to_cpu(block->bb_rightsib) == NULLDFSBNO ||
		 XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_rightsib)));
	if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp, XFS_ERRTAG_BTREE_CHECK_LBLOCK,
			XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
		if (bp)
			xfs_buftrace("LBTREE ERROR", bp);
		XFS_ERROR_REPORT("xfs_btree_check_lblock", XFS_ERRLEVEL_LOW,
				 mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	return 0;
}

/*
 * Checking routine: check that (long) pointer is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_lptr(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_dfsbno_t	ptr,		/* btree block disk address */
	int		level)		/* btree block level */
{
	xfs_mount_t	*mp;		/* file system mount point */

	mp = cur->bc_mp;
	XFS_WANT_CORRUPTED_RETURN(
		level > 0 &&
		ptr != NULLDFSBNO &&
		XFS_FSB_SANITY_CHECK(mp, ptr));
	return 0;
}

#ifdef DEBUG
/*
 * Debug routine: check that records are in the right order.
 */
void
xfs_btree_check_rec(
	xfs_btnum_t	btnum,		/* btree identifier */
	void		*ar1,		/* pointer to left (lower) record */
	void		*ar2)		/* pointer to right (higher) record */
{
	switch (btnum) {
	case XFS_BTNUM_BNO: {
		xfs_alloc_rec_t	*r1;
		xfs_alloc_rec_t	*r2;

		r1 = ar1;
		r2 = ar2;
		ASSERT(be32_to_cpu(r1->ar_startblock) +
		       be32_to_cpu(r1->ar_blockcount) <=
		       be32_to_cpu(r2->ar_startblock));
		break;
	    }
	case XFS_BTNUM_CNT: {
		xfs_alloc_rec_t	*r1;
		xfs_alloc_rec_t	*r2;

		r1 = ar1;
		r2 = ar2;
		ASSERT(be32_to_cpu(r1->ar_blockcount) < be32_to_cpu(r2->ar_blockcount) ||
		       (r1->ar_blockcount == r2->ar_blockcount &&
			be32_to_cpu(r1->ar_startblock) < be32_to_cpu(r2->ar_startblock)));
		break;
	    }
	case XFS_BTNUM_BMAP: {
		xfs_bmbt_rec_t	*r1;
		xfs_bmbt_rec_t	*r2;

		r1 = ar1;
		r2 = ar2;
		ASSERT(xfs_bmbt_disk_get_startoff(r1) +
		       xfs_bmbt_disk_get_blockcount(r1) <=
		       xfs_bmbt_disk_get_startoff(r2));
		break;
	    }
	case XFS_BTNUM_INO: {
		xfs_inobt_rec_t	*r1;
		xfs_inobt_rec_t	*r2;

		r1 = ar1;
		r2 = ar2;
		ASSERT(be32_to_cpu(r1->ir_startino) + XFS_INODES_PER_CHUNK <=
		       be32_to_cpu(r2->ir_startino));
		break;
	    }
	default:
		ASSERT(0);
	}
}
#endif	/* DEBUG */

/*
 * Checking routine: check that block header is ok.
 */
/* ARGSUSED */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_sblock(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_sblock_t	*block,	/* btree short form block pointer */
	int			level,	/* level of the btree block */
	xfs_buf_t		*bp)	/* buffer containing block */
{
	xfs_buf_t		*agbp;	/* buffer for ag. freespace struct */
	xfs_agf_t		*agf;	/* ag. freespace structure */
	xfs_agblock_t		agflen;	/* native ag. freespace length */
	int			sblock_ok; /* block passes checks */

	agbp = cur->bc_private.a.agbp;
	agf = XFS_BUF_TO_AGF(agbp);
	agflen = be32_to_cpu(agf->agf_length);
	sblock_ok =
		be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
		be16_to_cpu(block->bb_level) == level &&
		be16_to_cpu(block->bb_numrecs) <=
			xfs_btree_maxrecs(cur, (xfs_btree_block_t *)block) &&
		(be32_to_cpu(block->bb_leftsib) == NULLAGBLOCK ||
		 be32_to_cpu(block->bb_leftsib) < agflen) &&
		block->bb_leftsib &&
		(be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK ||
		 be32_to_cpu(block->bb_rightsib) < agflen) &&
		block->bb_rightsib;
	if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
			XFS_ERRTAG_BTREE_CHECK_SBLOCK,
			XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
		if (bp)
			xfs_buftrace("SBTREE ERROR", bp);
		XFS_ERROR_REPORT("xfs_btree_check_sblock", XFS_ERRLEVEL_LOW,
				 cur->bc_mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	return 0;
}

/*
 * Checking routine: check that (short) pointer is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_sptr(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agblock_t	ptr,		/* btree block disk address */
	int		level)		/* btree block level */
{
	xfs_buf_t	*agbp;		/* buffer for ag. freespace struct */
	xfs_agf_t	*agf;		/* ag. freespace structure */

	agbp = cur->bc_private.a.agbp;
	agf = XFS_BUF_TO_AGF(agbp);
	XFS_WANT_CORRUPTED_RETURN(
		level > 0 &&
		ptr != NULLAGBLOCK && ptr != 0 &&
		ptr < be32_to_cpu(agf->agf_length));
	return 0;
}

/*
 * Delete the btree cursor.
 */
void
xfs_btree_del_cursor(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		error)		/* del because of error */
{
	int		i;		/* btree level */

	/*
	 * Clear the buffer pointers, and release the buffers.
	 * If we're doing this in the face of an error, we
	 * need to make sure to inspect all of the entries
	 * in the bc_bufs array for buffers to be unlocked.
	 * This is because some of the btree code works from
	 * level n down to 0, and if we get an error along
	 * the way we won't have initialized all the entries
	 * down to 0.
	 */
	for (i = 0; i < cur->bc_nlevels; i++) {
		if (cur->bc_bufs[i])
			xfs_btree_setbuf(cur, i, NULL);
		else if (!error)
			break;
	}
	/*
	 * Can't free a bmap cursor without having dealt with the
	 * allocated indirect blocks' accounting.
	 */
	ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
	       cur->bc_private.b.allocated == 0);
	/*
	 * Free the cursor.
	 */
	kmem_zone_free(xfs_btree_cur_zone, cur);
}

/*
 * Duplicate the btree cursor.
 * Allocate a new one, copy the record, re-get the buffers.
 */
int					/* error */
xfs_btree_dup_cursor(
	xfs_btree_cur_t	*cur,		/* input cursor */
	xfs_btree_cur_t	**ncur)		/* output cursor */
{
	xfs_buf_t	*bp;		/* btree block's buffer pointer */
	int		error;		/* error return value */
	int		i;		/* level number of btree block */
	xfs_mount_t	*mp;		/* mount structure for filesystem */
	xfs_btree_cur_t	*new;		/* new cursor value */
	xfs_trans_t	*tp;		/* transaction pointer, can be NULL */

	tp = cur->bc_tp;
	mp = cur->bc_mp;
	/*
	 * Allocate a new cursor like the old one.
	 */
	new = xfs_btree_init_cursor(mp, tp, cur->bc_private.a.agbp,
		cur->bc_private.a.agno, cur->bc_btnum, cur->bc_private.b.ip,
		cur->bc_private.b.whichfork);
	/*
	 * Copy the record currently in the cursor.
	 */
	new->bc_rec = cur->bc_rec;
	/*
	 * For each level current, re-get the buffer and copy the ptr value.
	 */
	for (i = 0; i < new->bc_nlevels; i++) {
		new->bc_ptrs[i] = cur->bc_ptrs[i];
		new->bc_ra[i] = cur->bc_ra[i];
		if ((bp = cur->bc_bufs[i])) {
			if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
				XFS_BUF_ADDR(bp), mp->m_bsize, 0, &bp))) {
				xfs_btree_del_cursor(new, error);
				*ncur = NULL;
				return error;
			}
			new->bc_bufs[i] = bp;
			ASSERT(bp);
			ASSERT(!XFS_BUF_GETERROR(bp));
		} else
			new->bc_bufs[i] = NULL;
	}
	/*
	 * For bmap btrees, copy the firstblock, flist, and flags values,
	 * since init cursor doesn't get them.
	 */
	if (new->bc_btnum == XFS_BTNUM_BMAP) {
		new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
		new->bc_private.b.flist = cur->bc_private.b.flist;
		new->bc_private.b.flags = cur->bc_private.b.flags;
	}
	*ncur = new;
	return 0;
}

/*
 * Change the cursor to point to the first record at the given level.
 * Other levels are unaffected.
 */
int					/* success=1, failure=0 */
xfs_btree_firstrec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level)	/* level to change */
{
	xfs_btree_block_t	*block;	/* generic btree block pointer */
	xfs_buf_t		*bp;	/* buffer containing block */

	/*