btrfs: qgroup: Introduce helpers to update and access new qgroup rsv

 *  - check all ioctl parameters

 */

/*

 * Helpers to access qgroup reservation

 *

 * Callers should ensure the lock context and type are valid

 */

static u64 qgroup_rsv_total(const struct btrfs_qgroup *qgroup)

{

	u64 ret = 0;

	int i;

	for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)

		ret += qgroup->rsv.values[i];

	return ret;

}

#ifdef CONFIG_BTRFS_DEBUG

static const char *qgroup_rsv_type_str(enum btrfs_qgroup_rsv_type type)

{

	if (type == BTRFS_QGROUP_RSV_DATA)

		return "data";

	if (type == BTRFS_QGROUP_RSV_META)

		return "meta";

	return NULL;

}

#endif

static void qgroup_rsv_add(struct btrfs_qgroup *qgroup, u64 num_bytes,

			   enum btrfs_qgroup_rsv_type type)

{

	qgroup->rsv.values[type] += num_bytes;

}

static void qgroup_rsv_release(struct btrfs_qgroup *qgroup, u64 num_bytes,

			       enum btrfs_qgroup_rsv_type type)

{

	if (qgroup->rsv.values[type] >= num_bytes) {

		qgroup->rsv.values[type] -= num_bytes;

		return;

	}

#ifdef CONFIG_BTRFS_DEBUG

	WARN_RATELIMIT(1,

		"qgroup %llu %s reserved space underflow, have %llu to free %llu",

		qgroup->qgroupid, qgroup_rsv_type_str(type),

		qgroup->rsv.values[type], num_bytes);

#endif

	qgroup->rsv.values[type] = 0;

}

static void qgroup_rsv_add_by_qgroup(struct btrfs_qgroup *dest,

					  struct btrfs_qgroup *src)

{

	int i;

	for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)

		qgroup_rsv_add(dest, src->rsv.values[i], i);

}

static void qgroup_rsv_release_by_qgroup(struct btrfs_qgroup *dest,

					  struct btrfs_qgroup *src)

{

	int i;

	for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)

		qgroup_rsv_release(dest, src->rsv.values[i], i);

}

static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,

					   int mod)

{