ldm.c

linux 内核源代码

	 * The last_vblkd_seq can be before the end of the vmdb, just make sure
	 * it is not out of bounds.
	 */
	if ((vm->vblk_size * vm->last_vblk_seq) > (toc->bitmap1_size << 9)) {
		ldm_crit ("VMDB exceeds allowed size specified by TOCBLOCK.  "
				"Database is corrupt.  Aborting.");
		goto out;
	}

	result = true;
out:
	put_dev_sector (sect);
	return result;
}


/**
 * ldm_validate_partition_table - Determine whether bdev might be a dynamic disk
 * @bdev:  Device holding the LDM Database
 *
 * This function provides a weak test to decide whether the device is a dynamic
 * disk or not.  It looks for an MS-DOS-style partition table containing at
 * least one partition of type 0x42 (formerly SFS, now used by Windows for
 * dynamic disks).
 *
 * N.B.  The only possible error can come from the read_dev_sector and that is
 *       only likely to happen if the underlying device is strange.  If that IS
 *       the case we should return zero to let someone else try.
 *
 * Return:  'true'   @bdev is a dynamic disk
 *          'false'  @bdev is not a dynamic disk, or an error occurred
 */
static bool ldm_validate_partition_table (struct block_device *bdev)
{
	Sector sect;
	u8 *data;
	struct partition *p;
	int i;
	bool result = false;

	BUG_ON (!bdev);

	data = read_dev_sector (bdev, 0, &sect);
	if (!data) {
		ldm_crit ("Disk read failed.");
		return false;
	}

	if (*(__le16*) (data + 0x01FE) != cpu_to_le16 (MSDOS_LABEL_MAGIC))
		goto out;

	p = (struct partition*)(data + 0x01BE);
	for (i = 0; i < 4; i++, p++)
		if (SYS_IND (p) == LDM_PARTITION) {
			result = true;
			break;
		}

	if (result)
		ldm_debug ("Found W2K dynamic disk partition type.");

out:
	put_dev_sector (sect);
	return result;
}

/**
 * ldm_get_disk_objid - Search a linked list of vblk's for a given Disk Id
 * @ldb:  Cache of the database structures
 *
 * The LDM Database contains a list of all partitions on all dynamic disks.
 * The primary PRIVHEAD, at the beginning of the physical disk, tells us
 * the GUID of this disk.  This function searches for the GUID in a linked
 * list of vblk's.
 *
 * Return:  Pointer, A matching vblk was found
 *          NULL,    No match, or an error
 */
static struct vblk * ldm_get_disk_objid (const struct ldmdb *ldb)
{
	struct list_head *item;

	BUG_ON (!ldb);

	list_for_each (item, &ldb->v_disk) {
		struct vblk *v = list_entry (item, struct vblk, list);
		if (!memcmp (v->vblk.disk.disk_id, ldb->ph.disk_id, GUID_SIZE))
			return v;
	}

	return NULL;
}

/**
 * ldm_create_data_partitions - Create data partitions for this device
 * @pp:   List of the partitions parsed so far
 * @ldb:  Cache of the database structures
 *
 * The database contains ALL the partitions for ALL disk groups, so we need to
 * filter out this specific disk. Using the disk's object id, we can find all
 * the partitions in the database that belong to this disk.
 *
 * Add each partition in our database, to the parsed_partitions structure.
 *
 * N.B.  This function creates the partitions in the order it finds partition
 *       objects in the linked list.
 *
 * Return:  'true'   Partition created
 *          'false'  Error, probably a range checking problem
 */
static bool ldm_create_data_partitions (struct parsed_partitions *pp,
					const struct ldmdb *ldb)
{
	struct list_head *item;
	struct vblk *vb;
	struct vblk *disk;
	struct vblk_part *part;
	int part_num = 1;

	BUG_ON (!pp || !ldb);

	disk = ldm_get_disk_objid (ldb);
	if (!disk) {
		ldm_crit ("Can't find the ID of this disk in the database.");
		return false;
	}

	printk (" [LDM]");

	/* Create the data partitions */
	list_for_each (item, &ldb->v_part) {
		vb = list_entry (item, struct vblk, list);
		part = &vb->vblk.part;

		if (part->disk_id != disk->obj_id)
			continue;

		put_partition (pp, part_num, ldb->ph.logical_disk_start +
				part->start, part->size);
		part_num++;
	}

	printk ("\n");
	return true;
}


/**
 * ldm_relative - Calculate the next relative offset
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @base:    Size of the previous fixed width fields
 * @offset:  Cumulative size of the previous variable-width fields
 *
 * Because many of the VBLK fields are variable-width, it's necessary
 * to calculate each offset based on the previous one and the length
 * of the field it pointed to.
 *
 * Return:  -1 Error, the calculated offset exceeded the size of the buffer
 *           n OK, a range-checked offset into buffer
 */
static int ldm_relative(const u8 *buffer, int buflen, int base, int offset)
{

	base += offset;
	if (!buffer || offset < 0 || base > buflen) {
		if (!buffer)
			ldm_error("!buffer");
		if (offset < 0)
			ldm_error("offset (%d) < 0", offset);
		if (base > buflen)
			ldm_error("base (%d) > buflen (%d)", base, buflen);
		return -1;
	}
	if (base + buffer[base] >= buflen) {
		ldm_error("base (%d) + buffer[base] (%d) >= buflen (%d)", base,
				buffer[base], buflen);
		return -1;
	}
	return buffer[base] + offset + 1;
}

/**
 * ldm_get_vnum - Convert a variable-width, big endian number, into cpu order
 * @block:  Pointer to the variable-width number to convert
 *
 * Large numbers in the LDM Database are often stored in a packed format.  Each
 * number is prefixed by a one byte width marker.  All numbers in the database
 * are stored in big-endian byte order.  This function reads one of these
 * numbers and returns the result
 *
 * N.B.  This function DOES NOT perform any range checking, though the most
 *       it will read is eight bytes.
 *
 * Return:  n A number
 *          0 Zero, or an error occurred
 */
static u64 ldm_get_vnum (const u8 *block)
{
	u64 tmp = 0;
	u8 length;

	BUG_ON (!block);

	length = *block++;

	if (length && length <= 8)
		while (length--)
			tmp = (tmp << 8) | *block++;
	else
		ldm_error ("Illegal length %d.", length);

	return tmp;
}

/**
 * ldm_get_vstr - Read a length-prefixed string into a buffer
 * @block:   Pointer to the length marker
 * @buffer:  Location to copy string to
 * @buflen:  Size of the output buffer
 *
 * Many of the strings in the LDM Database are not NULL terminated.  Instead
 * they are prefixed by a one byte length marker.  This function copies one of
 * these strings into a buffer.
 *
 * N.B.  This function DOES NOT perform any range checking on the input.
 *       If the buffer is too small, the output will be truncated.
 *
 * Return:  0, Error and @buffer contents are undefined
 *          n, String length in characters (excluding NULL)
 *          buflen-1, String was truncated.
 */
static int ldm_get_vstr (const u8 *block, u8 *buffer, int buflen)
{
	int length;

	BUG_ON (!block || !buffer);

	length = block[0];
	if (length >= buflen) {
		ldm_error ("Truncating string %d -> %d.", length, buflen);
		length = buflen - 1;
	}
	memcpy (buffer, block + 1, length);
	buffer[length] = 0;
	return length;
}


/**
 * ldm_parse_cmp3 - Read a raw VBLK Component object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Component object (version 3) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Component VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_cmp3 (const u8 *buffer, int buflen, struct vblk *vb)
{
	int r_objid, r_name, r_vstate, r_child, r_parent, r_stripe, r_cols, len;
	struct vblk_comp *comp;

	BUG_ON (!buffer || !vb);

	r_objid  = ldm_relative (buffer, buflen, 0x18, 0);
	r_name   = ldm_relative (buffer, buflen, 0x18, r_objid);
	r_vstate = ldm_relative (buffer, buflen, 0x18, r_name);
	r_child  = ldm_relative (buffer, buflen, 0x1D, r_vstate);
	r_parent = ldm_relative (buffer, buflen, 0x2D, r_child);

	if (buffer[0x12] & VBLK_FLAG_COMP_STRIPE) {
		r_stripe = ldm_relative (buffer, buflen, 0x2E, r_parent);
		r_cols   = ldm_relative (buffer, buflen, 0x2E, r_stripe);
		len = r_cols;
	} else {
		r_stripe = 0;
		r_cols   = 0;
		len = r_parent;
	}
	if (len < 0)
		return false;

	len += VBLK_SIZE_CMP3;
	if (len != BE32 (buffer + 0x14))
		return false;

	comp = &vb->vblk.comp;
	ldm_get_vstr (buffer + 0x18 + r_name, comp->state,
		sizeof (comp->state));
	comp->type      = buffer[0x18 + r_vstate];
	comp->children  = ldm_get_vnum (buffer + 0x1D + r_vstate);
	comp->parent_id = ldm_get_vnum (buffer + 0x2D + r_child);
	comp->chunksize = r_stripe ? ldm_get_vnum (buffer+r_parent+0x2E) : 0;

	return true;
}

/**
 * ldm_parse_dgr3 - Read a raw VBLK Disk Group object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Disk Group object (version 3) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Disk Group VBLK
 *          'false'  @vb contents are not defined
 */
static int ldm_parse_dgr3 (const u8 *buffer, int buflen, struct vblk *vb)
{
	int r_objid, r_name, r_diskid, r_id1, r_id2, len;
	struct vblk_dgrp *dgrp;

	BUG_ON (!buffer || !vb);

	r_objid  = ldm_relative (buffer, buflen, 0x18, 0);
	r_name   = ldm_relative (buffer, buflen, 0x18, r_objid);
	r_diskid = ldm_relative (buffer, buflen, 0x18, r_name);

	if (buffer[0x12] & VBLK_FLAG_DGR3_IDS) {
		r_id1 = ldm_relative (buffer, buflen, 0x24, r_diskid);
		r_id2 = ldm_relative (buffer, buflen, 0x24, r_id1);
		len = r_id2;
	} else {
		r_id1 = 0;
		r_id2 = 0;
		len = r_diskid;
	}
	if (len < 0)
		return false;

	len += VBLK_SIZE_DGR3;
	if (len != BE32 (buffer + 0x14))
		return false;

	dgrp = &vb->vblk.dgrp;
	ldm_get_vstr (buffer + 0x18 + r_name, dgrp->disk_id,
		sizeof (dgrp->disk_id));
	return true;
}

/**
 * ldm_parse_dgr4 - Read a raw VBLK Disk Group object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Disk Group object (version 4) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Disk Group VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_dgr4 (const u8 *buffer, int buflen, struct vblk *vb)
{
	char buf[64];
	int r_objid, r_name, r_id1, r_id2, len;
	struct vblk_dgrp *dgrp;

	BUG_ON (!buffer || !vb);

	r_objid  = ldm_relative (buffer, buflen, 0x18, 0);
	r_name   = ldm_relative (buffer, buflen, 0x18, r_objid);

	if (buffer[0x12] & VBLK_FLAG_DGR4_IDS) {
		r_id1 = ldm_relative (buffer, buflen, 0x44, r_name);
		r_id2 = ldm_relative (buffer, buflen, 0x44, r_id1);
		len = r_id2;
	} else {
		r_id1 = 0;
		r_id2 = 0;
		len = r_name;
	}
	if (len < 0)
		return false;

	len += VBLK_SIZE_DGR4;
	if (len != BE32 (buffer + 0x14))
		return false;

	dgrp = &vb->vblk.dgrp;

	ldm_get_vstr (buffer + 0x18 + r_objid, buf, sizeof (buf));
	return true;
}

/**
 * ldm_parse_dsk3 - Read a raw VBLK Disk object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Disk object (version 3) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Disk VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_dsk3 (const u8 *buffer, int buflen, struct vblk *vb)
{
	int r_objid, r_name, r_diskid, r_altname, len;
	struct vblk_disk *disk;

	BUG_ON (!buffer || !vb);

	r_objid   = ldm_relative (buffer, buflen, 0x18, 0);
	r_name    = ldm_relative (buffer, buflen, 0x18, r_objid);
	r_diskid  = ldm_relative (buffer, buflen, 0x18, r_name);
	r_altname = ldm_relative (buffer, buflen, 0x18, r_diskid);
	len = r_altname;
	if (len < 0)
		return false;

	len += VBLK_SIZE_DSK3;
	if (len != BE32 (buffer + 0x14))
		return false;

	disk = &vb->vblk.disk;
	ldm_get_vstr (buffer + 0x18 + r_diskid, disk->alt_name,
		sizeof (disk->alt_name));
	if (!ldm_parse_guid (buffer + 0x19 + r_name, disk->disk_id))
		return false;

	return true;
}

/**
 * ldm_parse_dsk4 - Read a raw VBLK Disk object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Disk object (version 4) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Disk VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_dsk4 (const u8 *buffer, int buflen, struct vblk *vb)
{
	int r_objid, r_name, len;
	struct vblk_disk *disk;

	BUG_ON (!buffer || !vb);

	r_objid = ldm_relative (buffer, buflen, 0x18, 0);
	r_name  = ldm_relative (buffer, buflen, 0x18, r_objid);
	len     = r_name;
	if (len < 0)
		return false;

	len += VBLK_SIZE_DSK4;
	if (len != BE32 (buffer + 0x14))
		return false;

	disk = &vb->vblk.disk;
	memcpy (disk->disk_id, buffer + 0x18 + r_name, GUID_SIZE);
	return true;
}

/**
 * ldm_parse_prt3 - Read a raw VBLK Partition object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Partition object (version 3) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Partition VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_prt3(const u8 *buffer, int buflen, struct vblk *vb)
{
	int r_objid, r_name, r_size, r_parent, r_diskid, r_index, len;
	struct vblk_part *part;

	BUG_ON(!buffer || !vb);
	r_objid = ldm_relative(buffer, buflen, 0x18, 0);
	if (r_objid < 0) {
		ldm_error("r_objid %d < 0", r_objid);
		return false;
	}
	r_name = ldm_relative(buffer, buflen, 0x18, r_objid);
	if (r_name < 0) {
		ldm_error("r_name %d < 0", r_name);
		return false;
	}
	r_size = ldm_relative(buffer, buflen, 0x34, r_name);
	if (r_size < 0) {
		ldm_error("r_size %d < 0", r_size);
		return false;
	}
	r_parent = ldm_relative(buffer, buflen, 0x34, r_size);
	if (r_parent < 0) {
		ldm_error("r_parent %d < 0", r_parent);
		return false;
	}
	r_diskid = ldm_relative(buffer, buflen, 0x34, r_parent);
	if (r_diskid < 0) {
		ldm_error("r_diskid %d < 0", r_diskid);
		return false;
	}
	if (buffer[0x12] & VBLK_FLAG_PART_INDEX) {
		r_index = ldm_relative(buffer, buflen, 0x34, r_diskid);
		if (r_index < 0) {
			ldm_error("r_index %d < 0", r_index);
			return false;
		}
		len = r_index;
	} else {
		r_index = 0;
		len = r_diskid;
	}
	if (len < 0) {
		ldm_error("len %d < 0", len);
		return false;
	}
	len += VBLK_SIZE_PRT3;