static void describe_balance_args(struct btrfs_balance_args *bargs, char *buf,
				 u32 size_buf)
{
	int ret;
	u32 size_bp = size_buf;
	char *bp = buf;
	u64 flags = bargs->flags;
	char tmp_buf[128] = {'\0'};

	if (!flags)
		return;

#define CHECK_APPEND_NOARG(a)						\
	do {								\
		ret = snprintf(bp, size_bp, (a));			\
		if (ret < 0 || ret >= size_bp)				\
			goto out_overflow;				\
		size_bp -= ret;						\
		bp += ret;						\
	} while (0)

#define CHECK_APPEND_1ARG(a, v1)					\
	do {								\
		ret = snprintf(bp, size_bp, (a), (v1));			\
		if (ret < 0 || ret >= size_bp)				\
			goto out_overflow;				\
		size_bp -= ret;						\
		bp += ret;						\
	} while (0)

#define CHECK_APPEND_2ARG(a, v1, v2)					\
	do {								\
		ret = snprintf(bp, size_bp, (a), (v1), (v2));		\
		if (ret < 0 || ret >= size_bp)				\
			goto out_overflow;				\
		size_bp -= ret;						\
		bp += ret;						\
	} while (0)

	if (flags & BTRFS_BALANCE_ARGS_CONVERT)
		CHECK_APPEND_1ARG("convert=%s,",
				  btrfs_bg_type_to_raid_name(bargs->target));

	if (flags & BTRFS_BALANCE_ARGS_SOFT)
		CHECK_APPEND_NOARG("soft,");

	if (flags & BTRFS_BALANCE_ARGS_PROFILES) {
		btrfs_describe_block_groups(bargs->profiles, tmp_buf,
					    sizeof(tmp_buf));
		CHECK_APPEND_1ARG("profiles=%s,", tmp_buf);
	}

	if (flags & BTRFS_BALANCE_ARGS_USAGE)
		CHECK_APPEND_1ARG("usage=%llu,", bargs->usage);

	if (flags & BTRFS_BALANCE_ARGS_USAGE_RANGE)
		CHECK_APPEND_2ARG("usage=%u..%u,",
				  bargs->usage_min, bargs->usage_max);

	if (flags & BTRFS_BALANCE_ARGS_DEVID)
		CHECK_APPEND_1ARG("devid=%llu,", bargs->devid);

	if (flags & BTRFS_BALANCE_ARGS_DRANGE)
		CHECK_APPEND_2ARG("drange=%llu..%llu,",
				  bargs->pstart, bargs->pend);

	if (flags & BTRFS_BALANCE_ARGS_VRANGE)
		CHECK_APPEND_2ARG("vrange=%llu..%llu,",
				  bargs->vstart, bargs->vend);

	if (flags & BTRFS_BALANCE_ARGS_LIMIT)
		CHECK_APPEND_1ARG("limit=%llu,", bargs->limit);

	if (flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)
		CHECK_APPEND_2ARG("limit=%u..%u,",
				bargs->limit_min, bargs->limit_max);

	if (flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE)
		CHECK_APPEND_2ARG("stripes=%u..%u,",
				  bargs->stripes_min, bargs->stripes_max);

#undef CHECK_APPEND_2ARG
#undef CHECK_APPEND_1ARG
#undef CHECK_APPEND_NOARG

out_overflow:

	if (size_bp < size_buf)
		buf[size_buf - size_bp - 1] = '\0'; /* remove last , */
	else
		buf[0] = '\0';
}