xfs_alloc_btree.c

linux 内核源代码

#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 (be32_to_cpu(block->bb_leftsib) == 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 = be32_to_cpu(*XFS_ALLOC_PTR_ADDR(block, cur->bc_ptrs[lev], cur));
		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] = be16_to_cpu(block->bb_numrecs);
	}
	*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 > be16_to_cpu(block->bb_numrecs) || 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 = be32_to_cpu(rec->ar_startblock);
		*len = be32_to_cpu(rec->ar_blockcount);
	}
	*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] <= be16_to_cpu(block->bb_numrecs)) {
		*stat = 1;
		return 0;
	}
	/*
	 * If we just went off the right edge of the tree, return failure.
	 */
	if (be32_to_cpu(block->bb_rightsib) == 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] <= be16_to_cpu(block->bb_numrecs))
			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 = be32_to_cpu(*XFS_ALLOC_PTR_ADDR(block, cur->bc_ptrs[lev], cur));
		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;
	nrec.ar_startblock = cpu_to_be32(cur->bc_rec.a.ar_startblock);
	nrec.ar_blockcount = cpu_to_be32(cur->bc_rec.a.ar_blockcount);
	ncur = NULL;
	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 caller's cursor, but otherwise we should
		 * if ncur is a new cursor or we're about to be done.
		 */
		if (pcur != cur && (ncur || nbno == NULLAGBLOCK)) {
			cur->bc_nlevels = pcur->bc_nlevels;
			xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
		}
		/*
		 * If we got a new cursor, switch to it.
		 */
		if (ncur) {
			pcur = ncur;
			ncur = NULL;
		}
	} while (nbno != NULLAGBLOCK);
	*stat = i;
	return 0;
}

/*
 * Lookup the record equal to [bno, len] in the btree given by cur.
 */
int					/* error */
xfs_alloc_lookup_eq(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agblock_t	bno,		/* starting block of extent */
	xfs_extlen_t	len,		/* length of extent */
	int		*stat)		/* success/failure */
{
	cur->bc_rec.a.ar_startblock = bno;
	cur->bc_rec.a.ar_blockcount = len;
	return xfs_alloc_lookup(cur, XFS_LOOKUP_EQ, stat);
}

/*
 * Lookup the first record greater than or equal to [bno, len]
 * in the btree given by cur.
 */
int					/* error */
xfs_alloc_lookup_ge(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agblock_t	bno,		/* starting block of extent */
	xfs_extlen_t	len,		/* length of extent */
	int		*stat)		/* success/failure */
{
	cur->bc_rec.a.ar_startblock = bno;
	cur->bc_rec.a.ar_blockcount = len;
	return xfs_alloc_lookup(cur, XFS_LOOKUP_GE, stat);
}

/*
 * Lookup the first record less than or equal to [bno, len]
 * in the btree given by cur.
 */
int					/* error */
xfs_alloc_lookup_le(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agblock_t	bno,		/* starting block of extent */
	xfs_extlen_t	len,		/* length of extent */
	int		*stat)		/* success/failure */
{
	cur->bc_rec.a.ar_startblock = bno;
	cur->bc_rec.a.ar_blockcount = len;
	return xfs_alloc_lookup(cur, XFS_LOOKUP_LE, stat);
}

/*
 * Update the record referred to by cur, to the value given by [bno, len].
 * This either works (return 0) or gets an EFSCORRUPTED error.
 */
int					/* error */
xfs_alloc_update(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_agblock_t		bno,	/* starting block of extent */
	xfs_extlen_t		len)	/* length of extent */
{
	xfs_alloc_block_t	*block;	/* btree block to update */
	int			error;	/* error return value */
	int			ptr;	/* current record number (updating) */

	ASSERT(len > 0);
	/*
	 * Pick up the a.g. freelist struct and the current block.
	 */
	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
	/*
	 * Get the address of the rec to be updated.
	 */
	ptr = cur->bc_ptrs[0];
	{
		xfs_alloc_rec_t		*rp;	/* pointer to updated record */

		rp = XFS_ALLOC_REC_ADDR(block, ptr, cur);
		/*
		 * Fill in the new contents and log them.
		 */
		rp->ar_startblock = cpu_to_be32(bno);
		rp->ar_blockcount = cpu_to_be32(len);
		xfs_alloc_log_recs(cur, cur->bc_bufs[0], ptr, ptr);
	}
	/*
	 * If it's the by-size btree and it's the last leaf block and
	 * it's the last record... then update the size of the longest
	 * extent in the a.g., which we cache in the a.g. freelist header.
	 */
	if (cur->bc_btnum == XFS_BTNUM_CNT &&
	    be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK &&
	    ptr == be16_to_cpu(block->bb_numrecs)) {
		xfs_agf_t	*agf;	/* a.g. freespace header */
		xfs_agnumber_t	seqno;

		agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
		seqno = be32_to_cpu(agf->agf_seqno);
		cur->bc_mp->m_perag[seqno].pagf_longest = len;
		agf->agf_longest = cpu_to_be32(len);
		xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
			XFS_AGF_LONGEST);
	}
	/*
	 * Updating first record in leaf. Pass new key value up to our parent.
	 */
	if (ptr == 1) {
		xfs_alloc_key_t	key;	/* key containing [bno, len] */

		key.ar_startblock = cpu_to_be32(bno);
		key.ar_blockcount = cpu_to_be32(len);
		if ((error = xfs_alloc_updkey(cur, &key, 1)))
			return error;