RETURN(-EINVAL);
RETURN(0);
}
+
+/*
+ * Set/clear edquot flag after quota space allocation/release or settings
+ * change. Slaves will be notified of changes via glimpse on per-ID lock
+ *
+ * \param lqe - is the quota entry to check
+ * \param now - is the current time in second used for grace time managment
+ */
+void qmt_adjust_edquot(struct lquota_entry *lqe, __u64 now)
+{
+ struct qmt_pool_info *pool = lqe2qpi(lqe);
+
+ if (!lqe->lqe_enforced)
+ RETURN_EXIT;
+
+ if (!lqe->lqe_edquot) {
+ /* space exhausted flag not set, let's check whether it is time
+ * to set the flag */
+
+ if (!qmt_space_exhausted(lqe, now))
+ /* the qmt still has available space */
+ RETURN_EXIT;
+
+ if (lqe->lqe_qunit != pool->qpi_least_qunit)
+ /* we haven't reached the minimal qunit yet, so there is
+ * still hope that the rebalancing process might free up
+ * some quota space */
+ RETURN_EXIT;
+
+ if (lqe->lqe_may_rel != 0 &&
+ cfs_time_beforeq_64(lqe->lqe_revoke_time,
+ cfs_time_shift_64(-QMT_REBA_TIMEOUT)))
+ /* Let's give more time to slave to release space */
+ RETURN_EXIT;
+
+ /* set edquot flag */
+ lqe->lqe_edquot = true;
+ } else {
+ /* space exhausted flag set, let's check whether it is time to
+ * clear it */
+
+ if (qmt_space_exhausted(lqe, now))
+ /* the qmt still has not space */
+ RETURN_EXIT;
+
+ if (lqe->lqe_hardlimit != 0 &&
+ lqe->lqe_granted + pool->qpi_least_qunit >
+ lqe->lqe_hardlimit)
+ /* we clear the flag only once at least one least qunit
+ * is available */
+ RETURN_EXIT;
+
+ /* clear edquot flag */
+ lqe->lqe_edquot = false;
+ }
+
+ LQUOTA_DEBUG(lqe, "changing edquot flag");
+
+ /* let's notify slave by issuing glimpse on per-ID lock.
+ * the rebalance thread will take care of this */
+ qmt_id_lock_notify(pool->qpi_qmt, lqe);
+}
+
+/*
+ * Try to grant more quota space back to slave.
+ *
+ * \param lqe - is the quota entry for which we would like to allocate more
+ * space
+ * \param granted - is how much was already granted as part of the request
+ * processing
+ * \param spare - is how much unused quota space the slave already owns
+ *
+ * \retval return how additional space can be granted to the slave
+ */
+__u64 qmt_alloc_expand(struct lquota_entry *lqe, __u64 granted, __u64 spare)
+{
+ struct qmt_pool_info *pool = lqe2qpi(lqe);
+ __u64 remaining, qunit;
+ int slv_cnt;
+
+ LASSERT(lqe->lqe_enforced && lqe->lqe_qunit != 0);
+
+ slv_cnt = lqe2qpi(lqe)->qpi_slv_nr[lqe->lqe_site->lqs_qtype];
+ qunit = lqe->lqe_qunit;
+
+ if (lqe->lqe_softlimit != 0)
+ remaining = lqe->lqe_softlimit;
+ else
+ remaining = lqe->lqe_hardlimit;
+
+ if (lqe->lqe_granted >= remaining)
+ RETURN(0);
+
+ remaining -= lqe->lqe_granted;
+
+ do {
+ if (spare >= qunit)
+ break;
+
+ granted &= (qunit - 1);
+
+ if (remaining > (slv_cnt * qunit) >> 1) {
+ /* enough room to grant more space w/o additional
+ * shrinking ... at least for now */
+ remaining -= (slv_cnt * qunit) >> 1;
+ } else if (qunit != pool->qpi_least_qunit) {
+ qunit >>= 2;
+ continue;
+ }
+
+ granted &= (qunit - 1);
+ if (spare > 0)
+ RETURN(min_t(__u64, qunit - spare, remaining));
+ else
+ RETURN(min_t(__u64, qunit - granted, remaining));
+ } while (qunit >= pool->qpi_least_qunit);
+
+ RETURN(0);
+}
+
+/*
+ * Adjust qunit size according to quota limits and total granted count.
+ * The caller must have locked the lqe.
+ *
+ * \param env - the environment passed by the caller
+ * \param lqe - is the qid entry to be adjusted
+ */
+void qmt_adjust_qunit(const struct lu_env *env, struct lquota_entry *lqe)
+{
+ struct qmt_pool_info *pool = lqe2qpi(lqe);
+ int slv_cnt;
+ __u64 qunit, limit;
+ ENTRY;
+
+ LASSERT(lqe_is_locked(lqe));
+
+ if (!lqe->lqe_enforced)
+ /* no quota limits */
+ RETURN_EXIT;
+
+ /* record how many slaves have already registered */
+ slv_cnt = pool->qpi_slv_nr[lqe->lqe_site->lqs_qtype];
+ if (slv_cnt == 0)
+ /* wait for at least one slave to join */
+ RETURN_EXIT;
+
+ /* Qunit calculation is based on soft limit, if any, hard limit
+ * otherwise. This means that qunit is shrunk to the minimum when
+ * beyond the soft limit. This will impact performance, but that's the
+ * price of an accurate grace time management. */
+ if (lqe->lqe_softlimit != 0) {
+ limit = lqe->lqe_softlimit;
+ } else if (lqe->lqe_hardlimit != 0) {
+ limit = lqe->lqe_hardlimit;
+ } else {
+ LQUOTA_ERROR(lqe, "enforced bit set, but neither hard nor soft "
+ "limit are set");
+ RETURN_EXIT;
+ }
+
+ qunit = lqe->lqe_qunit == 0 ? pool->qpi_least_qunit : lqe->lqe_qunit;
+
+ /* The qunit value is computed as follows: limit / (2 * slv_cnt).
+ * Then 75% of the quota space can be granted with current qunit value.
+ * The remaining 25% are then used with reduced qunit size (by a factor
+ * of 4) which is then divided in a similar manner.
+ *
+ * |---------------------limit---------------------|
+ * |-------limit / 2-------|-limit / 4-|-limit / 4-|
+ * |qunit|qunit|qunit|qunit| | |
+ * |----slv_cnt * qunit----| | |
+ * |-grow limit-| | | |
+ * |--------------shrink limit---------| |
+ * |---space granted in qunit chunks---|-remaining-|
+ * / \
+ * / \
+ * / \
+ * / \
+ * / \
+ * qunit >>= 2; |qunit*slv_cnt|qunit*slv_cnt|
+ * |---space in qunit---|remain|
+ * ... */
+ if (qunit == pool->qpi_least_qunit ||
+ limit >= lqe->lqe_granted + ((slv_cnt * qunit) >> 1)) {
+ /* current qunit value still fits, let's see if we can afford to
+ * increase qunit now ...
+ * To increase qunit again, we have to be under 25% */
+ while (limit >= lqe->lqe_granted + 6 * qunit * slv_cnt)
+ qunit <<= 2;
+ } else {
+ /* shrink qunit until we find a suitable value */
+ while (qunit > pool->qpi_least_qunit &&
+ limit < lqe->lqe_granted + ((slv_cnt * qunit) >> 1))
+ qunit >>= 2;
+ }
+
+ if (lqe->lqe_qunit == qunit)
+ /* keep current qunit */
+ RETURN_EXIT;
+
+ LQUOTA_DEBUG(lqe, "%s qunit to "LPU64,
+ lqe->lqe_qunit < qunit ? "increasing" : "decreasing",
+ qunit);
+
+ /* store new qunit value */
+ swap(lqe->lqe_qunit, qunit);
+
+ /* reset revoke time */
+ lqe->lqe_revoke_time = 0;
+
+ if (lqe->lqe_qunit < qunit)
+ /* let's notify slave of qunit shrinking */
+ qmt_id_lock_notify(pool->qpi_qmt, lqe);
+ else if (lqe->lqe_qunit == pool->qpi_least_qunit)
+ /* initial qunit value is the smallest one */
+ lqe->lqe_revoke_time = cfs_time_current_64();
+ EXIT;
+}
+
+/*
+ * Adjust qunit & edquot flag in case it wasn't initialized already (e.g.
+ * limit set while no slaves were connected yet)
+ */
+void qmt_revalidate(const struct lu_env *env, struct lquota_entry *lqe)
+{
+ if (lqe->lqe_qunit == 0) {
+ /* lqe was read from disk, but neither qunit, nor edquot flag
+ * were initialized */
+ qmt_adjust_qunit(env, lqe);
+ if (lqe->lqe_qunit != 0)
+ qmt_adjust_edquot(lqe, cfs_time_current_sec());
+ }
+}