xfs_alloc_btree.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,070 行 · 第 1/5 页

				return error;
		}
#endif
		memcpy(rkp, lkp, INT_GET(right->bb_numrecs, ARCH_CONVERT) * sizeof(*rkp)); /* INT_: copy */
		memcpy(rpp, lpp, INT_GET(right->bb_numrecs, ARCH_CONVERT) * sizeof(*rpp)); /* INT_: copy */
		xfs_alloc_log_keys(cur, rbp, 1, INT_GET(right->bb_numrecs, ARCH_CONVERT));
		xfs_alloc_log_ptrs(cur, rbp, 1, INT_GET(right->bb_numrecs, ARCH_CONVERT));
		*keyp = *rkp;
	}
	/*
	 * For leaf blocks, copy records over to the new block.
	 */
	else {
		xfs_alloc_rec_t	*lrp;	/* left btree record pointer */
		xfs_alloc_rec_t	*rrp;	/* right btree record pointer */

		lrp = XFS_ALLOC_REC_ADDR(left, i, cur);
		rrp = XFS_ALLOC_REC_ADDR(right, 1, cur);
		memcpy(rrp, lrp, INT_GET(right->bb_numrecs, ARCH_CONVERT) * sizeof(*rrp));
		xfs_alloc_log_recs(cur, rbp, 1, INT_GET(right->bb_numrecs, ARCH_CONVERT));
		keyp->ar_startblock = rrp->ar_startblock; /* INT_: direct copy */
		keyp->ar_blockcount = rrp->ar_blockcount; /* INT_: direct copy */
	}
	/*
	 * Find the left block number by looking in the buffer.
	 * Adjust numrecs, sibling pointers.
	 */
	lbno = XFS_DADDR_TO_AGBNO(cur->bc_mp, XFS_BUF_ADDR(lbp));
	INT_MOD(left->bb_numrecs, ARCH_CONVERT, -(INT_GET(right->bb_numrecs, ARCH_CONVERT)));
	right->bb_rightsib = left->bb_rightsib; /* INT_: direct copy */
	INT_SET(left->bb_rightsib, ARCH_CONVERT, rbno);
	INT_SET(right->bb_leftsib, ARCH_CONVERT, lbno);
	xfs_alloc_log_block(cur->bc_tp, rbp, XFS_BB_ALL_BITS);
	xfs_alloc_log_block(cur->bc_tp, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
	/*
	 * If there's a block to the new block's right, make that block
	 * point back to right instead of to left.
	 */
	if (INT_GET(right->bb_rightsib, ARCH_CONVERT) != NULLAGBLOCK) {
		xfs_alloc_block_t	*rrblock;	/* rr btree block */
		xfs_buf_t		*rrbp;		/* buffer for rrblock */

		if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
				cur->bc_private.a.agno, INT_GET(right->bb_rightsib, ARCH_CONVERT), 0,
				&rrbp, XFS_ALLOC_BTREE_REF)))
			return error;
		rrblock = XFS_BUF_TO_ALLOC_BLOCK(rrbp);
		if ((error = xfs_btree_check_sblock(cur, rrblock, level, rrbp)))
			return error;
		INT_SET(rrblock->bb_leftsib, ARCH_CONVERT, rbno);
		xfs_alloc_log_block(cur->bc_tp, rrbp, XFS_BB_LEFTSIB);
	}
	/*
	 * If the cursor is really in the right block, move it there.
	 * If it's just pointing past the last entry in left, then we'll
	 * insert there, so don't change anything in that case.
	 */
	if (cur->bc_ptrs[level] > INT_GET(left->bb_numrecs, ARCH_CONVERT) + 1) {
		xfs_btree_setbuf(cur, level, rbp);
		cur->bc_ptrs[level] -= INT_GET(left->bb_numrecs, ARCH_CONVERT);
	}
	/*
	 * If there are more levels, we'll need another cursor which refers to
	 * the right block, no matter where this cursor was.
	 */
	if (level + 1 < cur->bc_nlevels) {
		if ((error = xfs_btree_dup_cursor(cur, curp)))
			return error;
		(*curp)->bc_ptrs[level + 1]++;
	}
	*bnop = rbno;
	*stat = 1;
	return 0;
}

/*
 * Update keys at all levels from here to the root along the cursor's path.
 */
STATIC int				/* error */
xfs_alloc_updkey(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_alloc_key_t		*keyp,	/* new key value to update to */
	int			level)	/* starting level for update */
{
	int			ptr;	/* index of key in block */

	/*
	 * Go up the tree from this level toward the root.
	 * At each level, update the key value to the value input.
	 * Stop when we reach a level where the cursor isn't pointing
	 * at the first entry in the block.
	 */
	for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
		xfs_alloc_block_t	*block;	/* btree block */
		xfs_buf_t		*bp;	/* buffer for block */
#ifdef DEBUG
		int			error;	/* error return value */
#endif
		xfs_alloc_key_t		*kp;	/* ptr to btree block keys */

		bp = cur->bc_bufs[level];
		block = XFS_BUF_TO_ALLOC_BLOCK(bp);
#ifdef DEBUG
		if ((error = xfs_btree_check_sblock(cur, block, level, bp)))
			return error;
#endif
		ptr = cur->bc_ptrs[level];
		kp = XFS_ALLOC_KEY_ADDR(block, ptr, cur);
		*kp = *keyp;
		xfs_alloc_log_keys(cur, bp, ptr, ptr);
	}
	return 0;
}

/*
 * Externally visible routines.
 */

/*
 * Decrement cursor by one record at the level.
 * For nonzero levels the leaf-ward information is untouched.
 */
int					/* error */
xfs_alloc_decrement(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level in btree, 0 is leaf */
	int			*stat)	/* success/failure */
{
	xfs_alloc_block_t	*block;	/* btree block */
	int			error;	/* error return value */
	int			lev;	/* btree level */

	ASSERT(level < cur->bc_nlevels);
	/*
	 * Read-ahead to the left at this level.
	 */
	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
	/*
	 * Decrement the ptr at this level.  If we're still in the block
	 * then we're done.
	 */
	if (--cur->bc_ptrs[level] > 0) {
		*stat = 1;
		return 0;
	}
	/*
	 * Get a pointer to the btree block.
	 */
	block = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[level]);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, level,
			cur->bc_bufs[level])))
		return error;
#endif
	/*
	 * If we just went off the left edge of the tree, return failure.
	 */
	if (INT_GET(block->bb_leftsib, ARCH_CONVERT) == NULLAGBLOCK) {
		*stat = 0;
		return 0;
	}
	/*
	 * March up the tree decrementing pointers.
	 * Stop when we don't go off the left edge of a block.
	 */
	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
		if (--cur->bc_ptrs[lev] > 0)
			break;
		/*
		 * Read-ahead the left block, we're going to read it
		 * in the next loop.
		 */
		xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
	}
	/*
	 * If we went off the root then we are seriously confused.
	 */
	ASSERT(lev < cur->bc_nlevels);
	/*
	 * Now walk back down the tree, fixing up the cursor's buffer
	 * pointers and key numbers.
	 */
	for (block = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[lev]); lev > level; ) {
		xfs_agblock_t	agbno;	/* block number of btree block */
		xfs_buf_t	*bp;	/* buffer pointer for block */

		agbno = INT_GET(*XFS_ALLOC_PTR_ADDR(block, cur->bc_ptrs[lev], cur), ARCH_CONVERT);
		if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
				cur->bc_private.a.agno, agbno, 0, &bp,
				XFS_ALLOC_BTREE_REF)))
			return error;
		lev--;
		xfs_btree_setbuf(cur, lev, bp);
		block = XFS_BUF_TO_ALLOC_BLOCK(bp);
		if ((error = xfs_btree_check_sblock(cur, block, lev, bp)))
			return error;
		cur->bc_ptrs[lev] = INT_GET(block->bb_numrecs, ARCH_CONVERT);
	}
	*stat = 1;
	return 0;
}

/*
 * Delete the record pointed to by cur.
 * The cursor refers to the place where the record was (could be inserted)
 * when the operation returns.
 */
int					/* error */
xfs_alloc_delete(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		*stat)		/* success/failure */
{
	int		error;		/* error return value */
	int		i;		/* result code */
	int		level;		/* btree level */

	/*
	 * Go up the tree, starting at leaf level.
	 * If 2 is returned then a join was done; go to the next level.
	 * Otherwise we are done.
	 */
	for (level = 0, i = 2; i == 2; level++) {
		if ((error = xfs_alloc_delrec(cur, level, &i)))
			return error;
	}
	if (i == 0) {
		for (level = 1; level < cur->bc_nlevels; level++) {
			if (cur->bc_ptrs[level] == 0) {
				if ((error = xfs_alloc_decrement(cur, level, &i)))
					return error;
				break;
			}
		}
	}
	*stat = i;
	return 0;
}

/*
 * Get the data from the pointed-to record.
 */
int					/* error */
xfs_alloc_get_rec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_agblock_t		*bno,	/* output: starting block of extent */
	xfs_extlen_t		*len,	/* output: length of extent */
	int			*stat)	/* output: success/failure */
{
	xfs_alloc_block_t	*block;	/* btree block */
#ifdef DEBUG
	int			error;	/* error return value */
#endif
	int			ptr;	/* record number */

	ptr = cur->bc_ptrs[0];
	block = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[0]);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, 0, cur->bc_bufs[0])))
		return error;
#endif
	/*
	 * Off the right end or left end, return failure.
	 */
	if (ptr > INT_GET(block->bb_numrecs, ARCH_CONVERT) || ptr <= 0) {
		*stat = 0;
		return 0;
	}
	/*
	 * Point to the record and extract its data.
	 */
	{
		xfs_alloc_rec_t		*rec;	/* record data */

		rec = XFS_ALLOC_REC_ADDR(block, ptr, cur);
		*bno = INT_GET(rec->ar_startblock, ARCH_CONVERT);
		*len = INT_GET(rec->ar_blockcount, ARCH_CONVERT);
	}
	*stat = 1;
	return 0;
}

/*
 * Increment cursor by one record at the level.
 * For nonzero levels the leaf-ward information is untouched.
 */
int					/* error */
xfs_alloc_increment(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level in btree, 0 is leaf */
	int			*stat)	/* success/failure */
{
	xfs_alloc_block_t	*block;	/* btree block */
	xfs_buf_t		*bp;	/* tree block buffer */
	int			error;	/* error return value */
	int			lev;	/* btree level */

	ASSERT(level < cur->bc_nlevels);
	/*
	 * Read-ahead to the right at this level.
	 */
	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
	/*
	 * Get a pointer to the btree block.
	 */
	bp = cur->bc_bufs[level];
	block = XFS_BUF_TO_ALLOC_BLOCK(bp);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, level, bp)))
		return error;
#endif
	/*
	 * Increment the ptr at this level.  If we're still in the block
	 * then we're done.
	 */
	if (++cur->bc_ptrs[level] <= INT_GET(block->bb_numrecs, ARCH_CONVERT)) {
		*stat = 1;
		return 0;
	}
	/*
	 * If we just went off the right edge of the tree, return failure.
	 */
	if (INT_GET(block->bb_rightsib, ARCH_CONVERT) == NULLAGBLOCK) {
		*stat = 0;
		return 0;
	}
	/*
	 * March up the tree incrementing pointers.
	 * Stop when we don't go off the right edge of a block.
	 */
	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
		bp = cur->bc_bufs[lev];
		block = XFS_BUF_TO_ALLOC_BLOCK(bp);
#ifdef DEBUG
		if ((error = xfs_btree_check_sblock(cur, block, lev, bp)))
			return error;
#endif
		if (++cur->bc_ptrs[lev] <= INT_GET(block->bb_numrecs, ARCH_CONVERT))
			break;
		/*
		 * Read-ahead the right block, we're going to read it
		 * in the next loop.
		 */
		xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
	}
	/*
	 * If we went off the root then we are seriously confused.
	 */
	ASSERT(lev < cur->bc_nlevels);
	/*
	 * Now walk back down the tree, fixing up the cursor's buffer
	 * pointers and key numbers.
	 */
	for (bp = cur->bc_bufs[lev], block = XFS_BUF_TO_ALLOC_BLOCK(bp);
	     lev > level; ) {
		xfs_agblock_t	agbno;	/* block number of btree block */

		agbno = INT_GET(*XFS_ALLOC_PTR_ADDR(block, cur->bc_ptrs[lev], cur), ARCH_CONVERT);
		if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
				cur->bc_private.a.agno, agbno, 0, &bp,
				XFS_ALLOC_BTREE_REF)))
			return error;
		lev--;
		xfs_btree_setbuf(cur, lev, bp);
		block = XFS_BUF_TO_ALLOC_BLOCK(bp);
		if ((error = xfs_btree_check_sblock(cur, block, lev, bp)))
			return error;
		cur->bc_ptrs[lev] = 1;
	}
	*stat = 1;
	return 0;
}

/*
 * Insert the current record at the point referenced by cur.
 * The cursor may be inconsistent on return if splits have been done.
 */
int					/* error */
xfs_alloc_insert(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		*stat)		/* success/failure */
{
	int		error;		/* error return value */
	int		i;		/* result value, 0 for failure */
	int		level;		/* current level number in btree */
	xfs_agblock_t	nbno;		/* new block number (split result) */
	xfs_btree_cur_t	*ncur;		/* new cursor (split result) */
	xfs_alloc_rec_t	nrec;		/* record being inserted this level */
	xfs_btree_cur_t	*pcur;		/* previous level's cursor */

	level = 0;
	nbno = NULLAGBLOCK;
	INT_SET(nrec.ar_startblock, ARCH_CONVERT, cur->bc_rec.a.ar_startblock);
	INT_SET(nrec.ar_blockcount, ARCH_CONVERT, cur->bc_rec.a.ar_blockcount);
	ncur = (xfs_btree_cur_t *)0;
	pcur = cur;
	/*
	 * Loop going up the tree, starting at the leaf level.
	 * Stop when we don't get a split block, that must mean that
	 * the insert is finished with this level.
	 */
	do {
		/*
		 * Insert nrec/nbno into this level of the tree.
		 * Note if we fail, nbno will be null.
		 */
		if ((error = xfs_alloc_insrec(pcur, level++, &nbno, &nrec, &ncur,
				&i))) {
			if (pcur != cur)
				xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
			return error;
		}
		/*
		 * See if the cursor we just used is trash.
		 * Can't trash the