dm-ioctl.c

linux 内核源代码

{
	if (strchr(name, '/')) {
		DMWARN("invalid device name");
		return -EINVAL;
	}

	return 0;
}

/*
 * Fills in a dm_ioctl structure, ready for sending back to
 * userland.
 */
static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
{
	struct gendisk *disk = dm_disk(md);
	struct dm_table *table;

	param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
			  DM_ACTIVE_PRESENT_FLAG);

	if (dm_suspended(md))
		param->flags |= DM_SUSPEND_FLAG;

	param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));

	/*
	 * Yes, this will be out of date by the time it gets back
	 * to userland, but it is still very useful for
	 * debugging.
	 */
	param->open_count = dm_open_count(md);

	if (disk->policy)
		param->flags |= DM_READONLY_FLAG;

	param->event_nr = dm_get_event_nr(md);

	table = dm_get_table(md);
	if (table) {
		param->flags |= DM_ACTIVE_PRESENT_FLAG;
		param->target_count = dm_table_get_num_targets(table);
		dm_table_put(table);
	} else
		param->target_count = 0;

	return 0;
}

static int dev_create(struct dm_ioctl *param, size_t param_size)
{
	int r, m = DM_ANY_MINOR;
	struct mapped_device *md;

	r = check_name(param->name);
	if (r)
		return r;

	if (param->flags & DM_PERSISTENT_DEV_FLAG)
		m = MINOR(huge_decode_dev(param->dev));

	r = dm_create(m, &md);
	if (r)
		return r;

	r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
	if (r) {
		dm_put(md);
		return r;
	}

	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

	r = __dev_status(md, param);
	dm_put(md);

	return r;
}

/*
 * Always use UUID for lookups if it's present, otherwise use name or dev.
 */
static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
{
	struct mapped_device *md;
	void *mdptr = NULL;

	if (*param->uuid)
		return __get_uuid_cell(param->uuid);

	if (*param->name)
		return __get_name_cell(param->name);

	md = dm_get_md(huge_decode_dev(param->dev));
	if (!md)
		goto out;

	mdptr = dm_get_mdptr(md);
	if (!mdptr)
		dm_put(md);

out:
	return mdptr;
}

static struct mapped_device *find_device(struct dm_ioctl *param)
{
	struct hash_cell *hc;
	struct mapped_device *md = NULL;

	down_read(&_hash_lock);
	hc = __find_device_hash_cell(param);
	if (hc) {
		md = hc->md;

		/*
		 * Sneakily write in both the name and the uuid
		 * while we have the cell.
		 */
		strncpy(param->name, hc->name, sizeof(param->name));
		if (hc->uuid)
			strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
		else
			param->uuid[0] = '\0';

		if (hc->new_map)
			param->flags |= DM_INACTIVE_PRESENT_FLAG;
		else
			param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
	}
	up_read(&_hash_lock);

	return md;
}

static int dev_remove(struct dm_ioctl *param, size_t param_size)
{
	struct hash_cell *hc;
	struct mapped_device *md;
	int r;

	down_write(&_hash_lock);
	hc = __find_device_hash_cell(param);

	if (!hc) {
		DMWARN("device doesn't appear to be in the dev hash table.");
		up_write(&_hash_lock);
		return -ENXIO;
	}

	md = hc->md;

	/*
	 * Ensure the device is not open and nothing further can open it.
	 */
	r = dm_lock_for_deletion(md);
	if (r) {
		DMWARN("unable to remove open device %s", hc->name);
		up_write(&_hash_lock);
		dm_put(md);
		return r;
	}

	__hash_remove(hc);
	up_write(&_hash_lock);
	dm_put(md);
	param->data_size = 0;
	return 0;
}

/*
 * Check a string doesn't overrun the chunk of
 * memory we copied from userland.
 */
static int invalid_str(char *str, void *end)
{
	while ((void *) str < end)
		if (!*str++)
			return 0;

	return -EINVAL;
}

static int dev_rename(struct dm_ioctl *param, size_t param_size)
{
	int r;
	char *new_name = (char *) param + param->data_start;

	if (new_name < (char *) param->data ||
	    invalid_str(new_name, (void *) param + param_size)) {
		DMWARN("Invalid new logical volume name supplied.");
		return -EINVAL;
	}

	r = check_name(new_name);
	if (r)
		return r;

	param->data_size = 0;
	return dm_hash_rename(param->name, new_name);
}

static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
{
	int r = -EINVAL, x;
	struct mapped_device *md;
	struct hd_geometry geometry;
	unsigned long indata[4];
	char *geostr = (char *) param + param->data_start;

	md = find_device(param);
	if (!md)
		return -ENXIO;

	if (geostr < (char *) param->data ||
	    invalid_str(geostr, (void *) param + param_size)) {
		DMWARN("Invalid geometry supplied.");
		goto out;
	}

	x = sscanf(geostr, "%lu %lu %lu %lu", indata,
		   indata + 1, indata + 2, indata + 3);

	if (x != 4) {
		DMWARN("Unable to interpret geometry settings.");
		goto out;
	}

	if (indata[0] > 65535 || indata[1] > 255 ||
	    indata[2] > 255 || indata[3] > ULONG_MAX) {
		DMWARN("Geometry exceeds range limits.");
		goto out;
	}

	geometry.cylinders = indata[0];
	geometry.heads = indata[1];
	geometry.sectors = indata[2];
	geometry.start = indata[3];

	r = dm_set_geometry(md, &geometry);
	if (!r)
		r = __dev_status(md, param);

	param->data_size = 0;

out:
	dm_put(md);
	return r;
}

static int do_suspend(struct dm_ioctl *param)
{
	int r = 0;
	unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
	struct mapped_device *md;

	md = find_device(param);
	if (!md)
		return -ENXIO;

	if (param->flags & DM_SKIP_LOCKFS_FLAG)
		suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
	if (param->flags & DM_NOFLUSH_FLAG)
		suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;

	if (!dm_suspended(md))
		r = dm_suspend(md, suspend_flags);

	if (!r)
		r = __dev_status(md, param);

	dm_put(md);
	return r;
}

static int do_resume(struct dm_ioctl *param)
{
	int r = 0;
	unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
	struct hash_cell *hc;
	struct mapped_device *md;
	struct dm_table *new_map;

	down_write(&_hash_lock);

	hc = __find_device_hash_cell(param);
	if (!hc) {
		DMWARN("device doesn't appear to be in the dev hash table.");
		up_write(&_hash_lock);
		return -ENXIO;
	}

	md = hc->md;

	new_map = hc->new_map;
	hc->new_map = NULL;
	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

	up_write(&_hash_lock);

	/* Do we need to load a new map ? */
	if (new_map) {
		/* Suspend if it isn't already suspended */
		if (param->flags & DM_SKIP_LOCKFS_FLAG)
			suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
		if (param->flags & DM_NOFLUSH_FLAG)
			suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
		if (!dm_suspended(md))
			dm_suspend(md, suspend_flags);

		r = dm_swap_table(md, new_map);
		if (r) {
			dm_put(md);
			dm_table_put(new_map);
			return r;
		}

		if (dm_table_get_mode(new_map) & FMODE_WRITE)
			set_disk_ro(dm_disk(md), 0);
		else
			set_disk_ro(dm_disk(md), 1);

		dm_table_put(new_map);
	}

	if (dm_suspended(md))
		r = dm_resume(md);

	if (!r)
		r = __dev_status(md, param);

	dm_put(md);
	return r;
}

/*
 * Set or unset the suspension state of a device.
 * If the device already is in the requested state we just return its status.
 */
static int dev_suspend(struct dm_ioctl *param, size_t param_size)
{
	if (param->flags & DM_SUSPEND_FLAG)
		return do_suspend(param);

	return do_resume(param);
}

/*
 * Copies device info back to user space, used by
 * the create and info ioctls.
 */
static int dev_status(struct dm_ioctl *param, size_t param_size)
{
	int r;
	struct mapped_device *md;

	md = find_device(param);
	if (!md)
		return -ENXIO;

	r = __dev_status(md, param);
	dm_put(md);
	return r;
}

/*
 * Build up the status struct for each target
 */
static void retrieve_status(struct dm_table *table,
			    struct dm_ioctl *param, size_t param_size)
{
	unsigned int i, num_targets;
	struct dm_target_spec *spec;
	char *outbuf, *outptr;
	status_type_t type;
	size_t remaining, len, used = 0;

	outptr = outbuf = get_result_buffer(param, param_size, &len);

	if (param->flags & DM_STATUS_TABLE_FLAG)
		type = STATUSTYPE_TABLE;
	else
		type = STATUSTYPE_INFO;

	/* Get all the target info */
	num_targets = dm_table_get_num_targets(table);
	for (i = 0; i < num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(table, i);

		remaining = len - (outptr - outbuf);
		if (remaining <= sizeof(struct dm_target_spec)) {
			param->flags |= DM_BUFFER_FULL_FLAG;
			break;
		}

		spec = (struct dm_target_spec *) outptr;

		spec->status = 0;
		spec->sector_start = ti->begin;
		spec->length = ti->len;
		strncpy(spec->target_type, ti->type->name,
			sizeof(spec->target_type));

		outptr += sizeof(struct dm_target_spec);
		remaining = len - (outptr - outbuf);
		if (remaining <= 0) {
			param->flags |= DM_BUFFER_FULL_FLAG;
			break;
		}

		/* Get the status/table string from the target driver */
		if (ti->type->status) {
			if (ti->type->status(ti, type, outptr, remaining)) {
				param->flags |= DM_BUFFER_FULL_FLAG;
				break;
			}
		} else
			outptr[0] = '\0';

		outptr += strlen(outptr) + 1;
		used = param->data_start + (outptr - outbuf);

		outptr = align_ptr(outptr);
		spec->next = outptr - outbuf;
	}

	if (used)
		param->data_size = used;

	param->target_count = num_targets;
}

/*
 * Wait for a device to report an event
 */
static int dev_wait(struct dm_ioctl *param, size_t param_size)
{
	int r;
	struct mapped_device *md;
	struct dm_table *table;

	md = find_device(param);
	if (!md)
		return -ENXIO;

	/*
	 * Wait for a notification event
	 */
	if (dm_wait_event(md, param->event_nr)) {
		r = -ERESTARTSYS;
		goto out;
	}

	/*
	 * The userland program is going to want to know what
	 * changed to trigger the event, so we may as well tell
	 * him and save an ioctl.
	 */
	r = __dev_status(md, param);
	if (r)
		goto out;

	table = dm_get_table(md);
	if (table) {
		retrieve_status(table, param, param_size);
		dm_table_put(table);
	}

 out:
	dm_put(md);
	return r;
}

static inline int get_mode(struct dm_ioctl *param)
{
	int mode = FMODE_READ | FMODE_WRITE;

	if (param->flags & DM_READONLY_FLAG)
		mode = FMODE_READ;

	return mode;
}

static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
		       struct dm_target_spec **spec, char **target_params)
{
	*spec = (struct dm_target_spec *) ((unsigned char *) last + next);
	*target_params = (char *) (*spec + 1);

	if (*spec < (last + 1))
		return -EINVAL;

	return invalid_str(*target_params, end);
}

static int populate_table(struct dm_table *table,
			  struct dm_ioctl *param, size_t param_size)
{
	int r;
	unsigned int i = 0;
	struct dm_target_spec *spec = (struct dm_target_spec *) param;
	uint32_t next = param->data_start;
	void *end = (void *) param + param_size;
	char *target_params;

	if (!param->target_count) {
		DMWARN("populate_table: no targets specified");
		return -EINVAL;
	}

	for (i = 0; i < param->target_count; i++) {

		r = next_target(spec, next, end, &spec, &target_params);
		if (r) {
			DMWARN("unable to find target");
			return r;