xfs_ialloc_btree.c

linux 内核源代码

		xfs_inobt_log_recs(cur, rbp, 1, be16_to_cpu(right->bb_numrecs));
		keyp->ir_startino = rrp->ir_startino;
	}
	/*
	 * Find the left block number by looking in the buffer.
	 * Adjust numrecs, sibling pointers.
	 */
	be16_add(&left->bb_numrecs, -(be16_to_cpu(right->bb_numrecs)));
	right->bb_rightsib = left->bb_rightsib;
	left->bb_rightsib = cpu_to_be32(args.agbno);
	right->bb_leftsib = cpu_to_be32(lbno);
	xfs_inobt_log_block(args.tp, rbp, XFS_BB_ALL_BITS);
	xfs_inobt_log_block(args.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 (be32_to_cpu(right->bb_rightsib) != NULLAGBLOCK) {
		xfs_inobt_block_t	*rrblock;	/* rr btree block */
		xfs_buf_t		*rrbp;		/* buffer for rrblock */

		if ((error = xfs_btree_read_bufs(args.mp, args.tp, args.agno,
				be32_to_cpu(right->bb_rightsib), 0, &rrbp,
				XFS_INO_BTREE_REF)))
			return error;
		rrblock = XFS_BUF_TO_INOBT_BLOCK(rrbp);
		if ((error = xfs_btree_check_sblock(cur, rrblock, level, rrbp)))
			return error;
		rrblock->bb_leftsib = cpu_to_be32(args.agbno);
		xfs_inobt_log_block(args.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] > be16_to_cpu(left->bb_numrecs) + 1) {
		xfs_btree_setbuf(cur, level, rbp);
		cur->bc_ptrs[level] -= be16_to_cpu(left->bb_numrecs);
	}
	/*
	 * If there are more levels, we'll need another cursor which refers
	 * 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 = args.agbno;
	*stat = 1;
	return 0;
}

/*
 * Update keys at all levels from here to the root along the cursor's path.
 */
STATIC int				/* error */
xfs_inobt_updkey(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_inobt_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_buf_t		*bp;	/* buffer for block */
		xfs_inobt_block_t	*block;	/* btree block */
#ifdef DEBUG
		int			error;	/* error return value */
#endif
		xfs_inobt_key_t		*kp;	/* ptr to btree block keys */

		bp = cur->bc_bufs[level];
		block = XFS_BUF_TO_INOBT_BLOCK(bp);
#ifdef DEBUG
		if ((error = xfs_btree_check_sblock(cur, block, level, bp)))
			return error;
#endif
		ptr = cur->bc_ptrs[level];
		kp = XFS_INOBT_KEY_ADDR(block, ptr, cur);
		*kp = *keyp;
		xfs_inobt_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_inobt_decrement(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level in btree, 0 is leaf */
	int			*stat)	/* success/failure */
{
	xfs_inobt_block_t	*block;	/* btree block */
	int			error;
	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_INOBT_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_INOBT_BLOCK(cur->bc_bufs[lev]); lev > level; ) {
		xfs_agblock_t	agbno;	/* block number of btree block */
		xfs_buf_t	*bp;	/* buffer containing btree block */

		agbno = be32_to_cpu(*XFS_INOBT_PTR_ADDR(block, cur->bc_ptrs[lev], cur));
		if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
				cur->bc_private.i.agno, agbno, 0, &bp,
				XFS_INO_BTREE_REF)))
			return error;
		lev--;
		xfs_btree_setbuf(cur, lev, bp);
		block = XFS_BUF_TO_INOBT_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_inobt_delete(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		*stat)		/* success/failure */
{
	int		error;
	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_inobt_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_inobt_decrement(cur, level, &i)))
					return error;
				break;
			}
		}
	}
	*stat = i;
	return 0;
}


/*
 * Get the data from the pointed-to record.
 */
int					/* error */
xfs_inobt_get_rec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_agino_t		*ino,	/* output: starting inode of chunk */
	__int32_t		*fcnt,	/* output: number of free inodes */
	xfs_inofree_t		*free,	/* output: free inode mask */
	int			*stat)	/* output: success/failure */
{
	xfs_inobt_block_t	*block;	/* btree block */
	xfs_buf_t		*bp;	/* buffer containing btree block */
#ifdef DEBUG
	int			error;	/* error return value */
#endif
	int			ptr;	/* record number */
	xfs_inobt_rec_t		*rec;	/* record data */

	bp = cur->bc_bufs[0];
	ptr = cur->bc_ptrs[0];
	block = XFS_BUF_TO_INOBT_BLOCK(bp);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, 0, bp)))
		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.
	 */
	rec = XFS_INOBT_REC_ADDR(block, ptr, cur);
	*ino = be32_to_cpu(rec->ir_startino);
	*fcnt = be32_to_cpu(rec->ir_freecount);
	*free = be64_to_cpu(rec->ir_free);
	*stat = 1;
	return 0;
}

/*
 * Increment cursor by one record at the level.
 * For nonzero levels the leaf-ward information is untouched.
 */
int					/* error */
xfs_inobt_increment(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level,	/* level in btree, 0 is leaf */
	int			*stat)	/* success/failure */
{
	xfs_inobt_block_t	*block;	/* btree block */
	xfs_buf_t		*bp;	/* buffer containing btree block */
	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_INOBT_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_INOBT_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_INOBT_BLOCK(bp);
	     lev > level; ) {
		xfs_agblock_t	agbno;	/* block number of btree block */

		agbno = be32_to_cpu(*XFS_INOBT_PTR_ADDR(block, cur->bc_ptrs[lev], cur));
		if ((error = xfs_btree_read_bufs(cur->bc_mp, cur->bc_tp,
				cur->bc_private.i.agno, agbno, 0, &bp,
				XFS_INO_BTREE_REF)))
			return error;
		lev--;
		xfs_btree_setbuf(cur, lev, bp);
		block = XFS_BUF_TO_INOBT_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_inobt_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_inobt_rec_t	nrec;		/* record being inserted this level */
	xfs_btree_cur_t	*pcur;		/* previous level's cursor */

	level = 0;
	nbno = NULLAGBLOCK;
	nrec.ir_startino = cpu_to_be32(cur->bc_rec.i.ir_startino);
	nrec.ir_freecount = cpu_to_be32(cur->bc_rec.i.ir_freecount);
	nrec.ir_free = cpu_to_be64(cur->bc_rec.i.ir_free);
	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_inobt_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 ino in the btree given by cur.
 */
int					/* error */
xfs_inobt_lookup_eq(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agino_t	ino,		/* starting inode of chunk */
	__int32_t	fcnt,		/* free inode count */
	xfs_inofree_t	free,		/* free inode mask */
	int		*stat)		/* success/failure */
{
	cur->bc_rec.i.ir_startino = ino;
	cur->bc_rec.i.ir_freecount = fcnt;
	cur->bc_rec.i.ir_free = free;
	return xfs_inobt_lookup(cur, XFS_LOOKUP_EQ, stat);
}

/*
 * Lookup the first record greater than or equal to ino
 * in the btree given by cur.
 */
int					/* error */
xfs_inobt_lookup_ge(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agino_t	ino,		/* starting inode of chunk */
	__int32_t	fcnt,		/* free inode count */
	xfs_inofree_t	free,		/* free inode mask */
	int		*stat)		/* success/failure */
{
	cur->bc_rec.i.ir_startino = ino;
	cur->bc_rec.i.ir_freecount = fcnt;
	cur->bc_rec.i.ir_free = free;
	return xfs_inobt_lookup(cur, XFS_LOOKUP_GE, stat);
}

/*
 * Lookup the first record less than or equal to ino
 * in the btree given by cur.
 */
int					/* error */
xfs_inobt_lookup_le(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	xfs_agino_t	ino,		/* starting inode of chunk */
	__int32_t	fcnt,		/* free inode count */
	xfs_inofree_t	free,		/* free inode mask */
	int		*stat)		/* success/failure */
{
	cur->bc_rec.i.ir_startino = ino;
	cur->bc_rec.i.ir_freecount = fcnt;
	cur->bc_rec.i.ir_free = free;
	return xfs_inobt_lookup(cur, XFS_LOOKUP_LE, stat);
}

/*
 * Update the record referred to by cur, to the value given
 * by [ino, fcnt, free].
 * This either works (return 0) or gets an EFSCORRUPTED error.
 */
int					/* error */
xfs_inobt_update(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_agino_t		ino,	/* starting inode of chunk */
	__int32_t		fcnt,	/* free inode count */
	xfs_inofree_t		free)	/* free inode mask */
{
	xfs_inobt_block_t	*block;	/* btree block to update */
	xfs_buf_t		*bp;	/* buffer containing btree block */
	int			error;	/* error return value */
	int			ptr;	/* current record number (updating) */
	xfs_inobt_rec_t		*rp;	/* pointer to updated record */

	/*
	 * Pick up the current block.
	 */
	bp = cur->bc_bufs[0];
	block = XFS_BUF_TO_INOBT_BLOCK(bp);
#ifdef DEBUG
	if ((error = xfs_btree_check_sblock(cur, block, 0, bp)))
		return error;
#endif
	/*
	 * Get the address of the rec to be updated.
	 */
	ptr = cur->bc_ptrs[0];
	rp = XFS_INOBT_REC_ADDR(block, ptr, cur);
	/*
	 * Fill in the new contents and log them.
	 */
	rp->ir_startino = cpu_to_be32(ino);
	rp->ir_freecount = cpu_to_be32(fcnt);
	rp->ir_free = cpu_to_be64(free);
	xfs_inobt_log_recs(cur, bp, ptr, ptr);
	/*
	 * Updating first record in leaf. Pass new key value up to our parent.
	 */
	if (ptr == 1) {
		xfs_inobt_key_t	key;	/* key containing [ino] */

		key.ir_startino = cpu_to_be32(ino);
		if ((error = xfs_inobt_updkey(cur, &key, 1)))
			return error;
	}
	return 0;
}