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LU-9859 lod: use linux kernel bitmap API
[fs/lustre-release.git] / lustre / lod / lod_qos.c
index 739720f..f4a7783 100644 (file)
 #define TGT_BAVAIL(i) (OST_TGT(lod,i)->ltd_statfs.os_bavail * \
                       OST_TGT(lod,i)->ltd_statfs.os_bsize)
 
+static inline int lod_statfs_check(struct lu_tgt_descs *ltd,
+                                  struct lu_tgt_desc *tgt)
+{
+       struct obd_statfs *sfs = &tgt->ltd_statfs;
+
+       if (((sfs->os_state & OS_STATFS_ENOSPC) ||
+           (!ltd->ltd_is_mdt && sfs->os_state & OS_STATFS_ENOINO &&
+            sfs->os_fprecreated == 0)))
+               return -ENOSPC;
+
+       /* If the OST is readonly then we can't allocate objects there */
+       if (sfs->os_state & OS_STATFS_READONLY)
+               return -EROFS;
+
+       /* object precreation is skipped on the OST with max_create_count=0 */
+       if (!ltd->ltd_is_mdt && sfs->os_state & OS_STATFS_NOPRECREATE)
+               return -ENOBUFS;
+
+       return 0;
+}
+
 /**
- * Check whether the target is available for new OST objects.
+ * Check whether the target is available for new objects.
  *
  * Request statfs data from the given target and verify it's active and not
- * read-only. If so, then it can be used to place new OST objects. This
+ * read-only. If so, then it can be used to place new objects. This
  * function also maintains the number of active/inactive targets and sets
  * dirty flags if those numbers change so others can run re-balance procedures.
  * No external locking is required.
  *
  * \param[in] env      execution environment for this thread
  * \param[in] d                LOD device
- * \param[in] index    index of OST target to check
- * \param[out] sfs     buffer for statfs data
+ * \param[in] ltd      target table
+ * \param[in] tgt      target
  *
  * \retval 0           if the target is good
  * \retval negative    negated errno on error
-
  */
 static int lod_statfs_and_check(const struct lu_env *env, struct lod_device *d,
-                               int index, struct obd_statfs *sfs)
+                               struct lu_tgt_descs *ltd,
+                               struct lu_tgt_desc *tgt, __u64 reserve)
 {
-       struct lod_tgt_desc *ost;
-       int                  rc;
+       struct obd_statfs_info info = { 0 };
+       struct lov_desc *desc = &ltd->ltd_lov_desc;
+       int rc;
        ENTRY;
 
        LASSERT(d);
-       ost = OST_TGT(d,index);
-       LASSERT(ost);
-
-       rc = dt_statfs(env, ost->ltd_ost, sfs);
-
-       if (rc == 0 && ((sfs->os_state & OS_STATE_ENOSPC) ||
-           (sfs->os_state & OS_STATE_ENOINO && sfs->os_fprecreated == 0)))
-               RETURN(-ENOSPC);
+       LASSERT(tgt);
 
+       info.os_enable_pre = 1;
+       rc = dt_statfs_info(env, tgt->ltd_tgt, &tgt->ltd_statfs, &info);
        if (rc && rc != -ENOTCONN)
                CERROR("%s: statfs: rc = %d\n", lod2obd(d)->obd_name, rc);
 
-       /* If the OST is readonly then we can't allocate objects there */
-       if (sfs->os_state & OS_STATE_READONLY)
-               rc = -EROFS;
+       if (!rc) {
+               rc = lod_statfs_check(ltd, tgt);
+               if (rc == -ENOSPC)
+                       return rc;
+       }
 
-       /* object precreation is skipped on the OST with max_create_count=0 */
-       if (sfs->os_state & OS_STATE_NOPRECREATE)
-               rc = -ENOBUFS;
+       if (reserve &&
+           (reserve + (info.os_reserved_mb_low << 20) >
+            tgt->ltd_statfs.os_bavail * tgt->ltd_statfs.os_bsize))
+               return -ENOSPC;
 
        /* check whether device has changed state (active, inactive) */
-       if (rc != 0 && ost->ltd_active) {
+       if (rc != 0 && tgt->ltd_active) {
                /* turned inactive? */
                spin_lock(&d->lod_lock);
-               if (ost->ltd_active) {
-                       ost->ltd_active = 0;
+               if (tgt->ltd_active) {
+                       tgt->ltd_active = 0;
                        if (rc == -ENOTCONN)
-                               ost->ltd_connecting = 1;
+                               tgt->ltd_connecting = 1;
 
-                       LASSERT(d->lod_desc.ld_active_tgt_count > 0);
-                       d->lod_desc.ld_active_tgt_count--;
-                       d->lod_qos.lq_dirty = 1;
-                       d->lod_qos.lq_rr.lqr_dirty = 1;
+                       LASSERT(desc->ld_active_tgt_count > 0);
+                       desc->ld_active_tgt_count--;
+                       set_bit(LQ_DIRTY, &ltd->ltd_qos.lq_flags);
+                       set_bit(LQ_DIRTY, &ltd->ltd_qos.lq_rr.lqr_flags);
                        CDEBUG(D_CONFIG, "%s: turns inactive\n",
-                              ost->ltd_exp->exp_obd->obd_name);
+                              tgt->ltd_exp->exp_obd->obd_name);
                }
                spin_unlock(&d->lod_lock);
-       } else if (rc == 0 && ost->ltd_active == 0) {
+       } else if (rc == 0 && tgt->ltd_active == 0) {
                /* turned active? */
-               LASSERTF(d->lod_desc.ld_active_tgt_count < d->lod_ostnr,
-                        "active tgt count %d, ost nr %d\n",
-                        d->lod_desc.ld_active_tgt_count, d->lod_ostnr);
+               LASSERTF(desc->ld_active_tgt_count < desc->ld_tgt_count,
+                        "active tgt count %d, tgt nr %d\n",
+                        desc->ld_active_tgt_count, desc->ld_tgt_count);
                spin_lock(&d->lod_lock);
-               if (ost->ltd_active == 0) {
-                       ost->ltd_active = 1;
-                       ost->ltd_connecting = 0;
-                       d->lod_desc.ld_active_tgt_count++;
-                       d->lod_qos.lq_dirty = 1;
-                       d->lod_qos.lq_rr.lqr_dirty = 1;
+               if (tgt->ltd_active == 0) {
+                       tgt->ltd_active = 1;
+                       tgt->ltd_connecting = 0;
+                       desc->ld_active_tgt_count++;
+                       set_bit(LQ_DIRTY, &ltd->ltd_qos.lq_flags);
+                       set_bit(LQ_DIRTY, &ltd->ltd_qos.lq_rr.lqr_flags);
                        CDEBUG(D_CONFIG, "%s: turns active\n",
-                              ost->ltd_exp->exp_obd->obd_name);
+                              tgt->ltd_exp->exp_obd->obd_name);
                }
                spin_unlock(&d->lod_lock);
        }
+       if (rc == -ENOTCONN) {
+               /* In case that the ENOTCONN for inactive OST state is
+                * mistreated as MDT disconnection state by the client,
+                * this error should be changed to someone else.
+                */
+               rc = -EREMOTEIO;
+       }
 
        RETURN(rc);
 }
 
+static int lod_is_tgt_usable(struct lu_tgt_descs *ltd, struct lu_tgt_desc *tgt)
+{
+       int rc;
+
+       rc = lod_statfs_check(ltd, tgt);
+       if (rc)
+               return rc;
+
+       if (!tgt->ltd_active)
+               return -ENOTCONN;
+
+       return 0;
+}
+
 /**
  * Maintain per-target statfs data.
  *
@@ -153,287 +194,44 @@ static int lod_statfs_and_check(const struct lu_env *env, struct lod_device *d,
  *
  * \param[in] env      execution environment for this thread
  * \param[in] lod      LOD device
+ * \param[in] ltd      tgt table
  */
-void lod_qos_statfs_update(const struct lu_env *env, struct lod_device *lod)
+void lod_qos_statfs_update(const struct lu_env *env, struct lod_device *lod,
+                          struct lu_tgt_descs *ltd)
 {
        struct obd_device *obd = lod2obd(lod);
-       struct ost_pool *osts = &(lod->lod_pool_info);
+       struct lu_tgt_desc *tgt;
        time64_t max_age;
-       unsigned int i;
        u64 avail;
-       int idx;
        ENTRY;
 
-       max_age = ktime_get_seconds() - 2 * lod->lod_desc.ld_qos_maxage;
+       max_age = ktime_get_seconds() - 2 * ltd->ltd_lov_desc.ld_qos_maxage;
 
        if (obd->obd_osfs_age > max_age)
                /* statfs data are quite recent, don't need to refresh it */
                RETURN_EXIT;
 
-       down_write(&lod->lod_qos.lq_rw_sem);
+       down_write(&ltd->ltd_qos.lq_rw_sem);
 
        if (obd->obd_osfs_age > max_age)
                goto out;
 
-       for (i = 0; i < osts->op_count; i++) {
-               idx = osts->op_array[i];
-               avail = OST_TGT(lod,idx)->ltd_statfs.os_bavail;
-               if (lod_statfs_and_check(env, lod, idx,
-                                        &OST_TGT(lod, idx)->ltd_statfs))
+       ltd_foreach_tgt(ltd, tgt) {
+               avail = tgt->ltd_statfs.os_bavail;
+               if (lod_statfs_and_check(env, lod, ltd, tgt, 0))
                        continue;
-               if (OST_TGT(lod,idx)->ltd_statfs.os_bavail != avail)
+
+               if (tgt->ltd_statfs.os_bavail != avail)
                        /* recalculate weigths */
-                       lod->lod_qos.lq_dirty = 1;
+                       set_bit(LQ_DIRTY, &ltd->ltd_qos.lq_flags);
        }
        obd->obd_osfs_age = ktime_get_seconds();
 
 out:
-       up_write(&lod->lod_qos.lq_rw_sem);
+       up_write(&ltd->ltd_qos.lq_rw_sem);
        EXIT;
 }
 
-/**
- * Calculate per-OST and per-OSS penalties
- *
- * Re-calculate penalties when the configuration changes, active targets
- * change and after statfs refresh (all these are reflected by lq_dirty flag).
- * On every OST and OSS: decay the penalty by half for every 8x the update
- * interval that the device has been idle. That gives lots of time for the
- * statfs information to be updated (which the penalty is only a proxy for),
- * and avoids penalizing OSS/OSTs under light load.
- * See lod_qos_calc_weight() for how penalties are factored into the weight.
- *
- * \param[in] lod      LOD device
- *
- * \retval 0           on success
- * \retval -EAGAIN     the number of OSTs isn't enough
- */
-static int lod_qos_calc_ppo(struct lod_device *lod)
-{
-       struct lu_svr_qos *oss;
-       __u64 ba_max, ba_min, temp;
-       __u32 num_active;
-       unsigned int i;
-       int rc, prio_wide;
-       time64_t now, age;
-
-       ENTRY;
-
-       if (!lod->lod_qos.lq_dirty)
-               GOTO(out, rc = 0);
-
-       num_active = lod->lod_desc.ld_active_tgt_count - 1;
-       if (num_active < 1)
-               GOTO(out, rc = -EAGAIN);
-
-       /* find bavail on each OSS */
-       list_for_each_entry(oss, &lod->lod_qos.lq_svr_list, lsq_svr_list)
-               oss->lsq_bavail = 0;
-       lod->lod_qos.lq_active_svr_count = 0;
-
-       /*
-        * How badly user wants to select OSTs "widely" (not recently chosen
-        * and not on recent OSS's).  As opposed to "freely" (free space
-        * avail.) 0-256
-        */
-       prio_wide = 256 - lod->lod_qos.lq_prio_free;
-
-       ba_min = (__u64)(-1);
-       ba_max = 0;
-       now = ktime_get_real_seconds();
-       /* Calculate OST penalty per object
-        * (lod ref taken in lod_qos_prep_create())
-        */
-       cfs_foreach_bit(lod->lod_ost_bitmap, i) {
-               LASSERT(OST_TGT(lod,i));
-               temp = TGT_BAVAIL(i);
-               if (!temp)
-                       continue;
-               ba_min = min(temp, ba_min);
-               ba_max = max(temp, ba_max);
-
-               /* Count the number of usable OSS's */
-               if (OST_TGT(lod, i)->ltd_qos.ltq_svr->lsq_bavail == 0)
-                       lod->lod_qos.lq_active_svr_count++;
-               OST_TGT(lod, i)->ltd_qos.ltq_svr->lsq_bavail += temp;
-
-               /* per-OST penalty is prio * TGT_bavail / (num_ost - 1) / 2 */
-               temp >>= 1;
-               do_div(temp, num_active);
-               OST_TGT(lod,i)->ltd_qos.ltq_penalty_per_obj =
-                       (temp * prio_wide) >> 8;
-
-               age = (now - OST_TGT(lod,i)->ltd_qos.ltq_used) >> 3;
-               if (lod->lod_qos.lq_reset ||
-                   age > 32 * lod->lod_desc.ld_qos_maxage)
-                       OST_TGT(lod,i)->ltd_qos.ltq_penalty = 0;
-               else if (age > lod->lod_desc.ld_qos_maxage)
-                       /* Decay OST penalty. */
-                       OST_TGT(lod,i)->ltd_qos.ltq_penalty >>=
-                               (age / lod->lod_desc.ld_qos_maxage);
-       }
-
-       num_active = lod->lod_qos.lq_active_svr_count - 1;
-       if (num_active < 1) {
-               /* If there's only 1 OSS, we can't penalize it, so instead
-                  we have to double the OST penalty */
-               num_active = 1;
-               cfs_foreach_bit(lod->lod_ost_bitmap, i)
-                       OST_TGT(lod,i)->ltd_qos.ltq_penalty_per_obj <<= 1;
-       }
-
-       /* Per-OSS penalty is prio * oss_avail / oss_osts / (num_oss - 1) / 2 */
-       list_for_each_entry(oss, &lod->lod_qos.lq_svr_list, lsq_svr_list) {
-               temp = oss->lsq_bavail >> 1;
-               do_div(temp, oss->lsq_tgt_count * num_active);
-               oss->lsq_penalty_per_obj = (temp * prio_wide) >> 8;
-
-               age = (now - oss->lsq_used) >> 3;
-               if (lod->lod_qos.lq_reset ||
-                   age > 32 * lod->lod_desc.ld_qos_maxage)
-                       oss->lsq_penalty = 0;
-               else if (age > lod->lod_desc.ld_qos_maxage)
-                       /* Decay OSS penalty. */
-                       oss->lsq_penalty >>= age / lod->lod_desc.ld_qos_maxage;
-       }
-
-       lod->lod_qos.lq_dirty = 0;
-       lod->lod_qos.lq_reset = 0;
-
-       /* If each ost has almost same free space,
-        * do rr allocation for better creation performance */
-       lod->lod_qos.lq_same_space = 0;
-       if ((ba_max * (256 - lod->lod_qos.lq_threshold_rr)) >> 8 < ba_min) {
-               lod->lod_qos.lq_same_space = 1;
-               /* Reset weights for the next time we enter qos mode */
-               lod->lod_qos.lq_reset = 1;
-       }
-       rc = 0;
-
-out:
-#ifndef FORCE_QOS
-       if (!rc && lod->lod_qos.lq_same_space)
-               RETURN(-EAGAIN);
-#endif
-       RETURN(rc);
-}
-
-/**
- * Calculate weight for a given OST target.
- *
- * The final OST weight is the number of bytes available minus the OST and
- * OSS penalties.  See lod_qos_calc_ppo() for how penalties are calculated.
- *
- * \param[in] lod      LOD device, where OST targets are listed
- * \param[in] i                OST target index
- *
- * \retval             0
- */
-static int lod_qos_calc_weight(struct lod_device *lod, int i)
-{
-       __u64 temp, temp2;
-
-       temp = TGT_BAVAIL(i);
-       temp2 = OST_TGT(lod, i)->ltd_qos.ltq_penalty +
-               OST_TGT(lod, i)->ltd_qos.ltq_svr->lsq_penalty;
-       if (temp < temp2)
-               OST_TGT(lod, i)->ltd_qos.ltq_weight = 0;
-       else
-               OST_TGT(lod, i)->ltd_qos.ltq_weight = temp - temp2;
-       return 0;
-}
-
-/**
- * Re-calculate weights.
- *
- * The function is called when some OST target was used for a new object. In
- * this case we should re-calculate all the weights to keep new allocations
- * balanced well.
- *
- * \param[in] lod      LOD device
- * \param[in] osts     OST pool where a new object was placed
- * \param[in] index    OST target where a new object was placed
- * \param[out] total_wt        new total weight for the pool
- *
- * \retval             0
- */
-static int lod_qos_used(struct lod_device *lod, struct ost_pool *osts,
-                       __u32 index, __u64 *total_wt)
-{
-       struct lod_tgt_desc *ost;
-       struct lu_svr_qos  *oss;
-       unsigned int j;
-       ENTRY;
-
-       ost = OST_TGT(lod,index);
-       LASSERT(ost);
-
-       /* Don't allocate on this devuce anymore, until the next alloc_qos */
-       ost->ltd_qos.ltq_usable = 0;
-
-       oss = ost->ltd_qos.ltq_svr;
-
-       /* Decay old penalty by half (we're adding max penalty, and don't
-          want it to run away.) */
-       ost->ltd_qos.ltq_penalty >>= 1;
-       oss->lsq_penalty >>= 1;
-
-       /* mark the OSS and OST as recently used */
-       ost->ltd_qos.ltq_used = oss->lsq_used = ktime_get_real_seconds();
-
-       /* Set max penalties for this OST and OSS */
-       ost->ltd_qos.ltq_penalty +=
-               ost->ltd_qos.ltq_penalty_per_obj * lod->lod_ostnr;
-       oss->lsq_penalty += oss->lsq_penalty_per_obj *
-               lod->lod_qos.lq_active_svr_count;
-
-       /* Decrease all OSS penalties */
-       list_for_each_entry(oss, &lod->lod_qos.lq_svr_list, lsq_svr_list) {
-               if (oss->lsq_penalty < oss->lsq_penalty_per_obj)
-                       oss->lsq_penalty = 0;
-               else
-                       oss->lsq_penalty -= oss->lsq_penalty_per_obj;
-       }
-
-       *total_wt = 0;
-       /* Decrease all OST penalties */
-       for (j = 0; j < osts->op_count; j++) {
-               int i;
-
-               i = osts->op_array[j];
-               if (!cfs_bitmap_check(lod->lod_ost_bitmap, i))
-                       continue;
-
-               ost = OST_TGT(lod,i);
-               LASSERT(ost);
-
-               if (ost->ltd_qos.ltq_penalty <
-                               ost->ltd_qos.ltq_penalty_per_obj)
-                       ost->ltd_qos.ltq_penalty = 0;
-               else
-                       ost->ltd_qos.ltq_penalty -=
-                               ost->ltd_qos.ltq_penalty_per_obj;
-
-               lod_qos_calc_weight(lod, i);
-
-               /* Recalc the total weight of usable osts */
-               if (ost->ltd_qos.ltq_usable)
-                       *total_wt += ost->ltd_qos.ltq_weight;
-
-               QOS_DEBUG("recalc tgt %d usable=%d avail=%llu"
-                         " ostppo=%llu ostp=%llu ossppo=%llu"
-                         " ossp=%llu wt=%llu\n",
-                         i, ost->ltd_qos.ltq_usable, TGT_BAVAIL(i) >> 10,
-                         ost->ltd_qos.ltq_penalty_per_obj >> 10,
-                         ost->ltd_qos.ltq_penalty >> 10,
-                         ost->ltd_qos.ltq_svr->lsq_penalty_per_obj >> 10,
-                         ost->ltd_qos.ltq_svr->lsq_penalty >> 10,
-                         ost->ltd_qos.ltq_weight >> 10);
-       }
-
-       RETURN(0);
-}
-
 #define LOV_QOS_EMPTY ((__u32)-1)
 
 /**
@@ -446,37 +244,39 @@ static int lod_qos_used(struct lod_device *lod, struct ost_pool *osts,
  * a new target or activation/deactivation).
  *
  * \param[in] lod      LOD device
- * \param[in] src_pool OST pool
+ * \param[in] ltd      tgt table
+ * \param[in] src_pool tgt pool
  * \param[in] lqr      round-robin list
  *
  * \retval 0           on success
  * \retval -ENOMEM     fails to allocate the array
  */
-static int lod_qos_calc_rr(struct lod_device *lod, struct ost_pool *src_pool,
+static int lod_qos_calc_rr(struct lod_device *lod, struct lu_tgt_descs *ltd,
+                          const struct lu_tgt_pool *src_pool,
                           struct lu_qos_rr *lqr)
 {
-       struct lu_svr_qos  *oss;
-       struct lod_tgt_desc *ost;
+       struct lu_svr_qos  *svr;
+       struct lu_tgt_desc *tgt;
        unsigned placed, real_count;
        unsigned int i;
        int rc;
        ENTRY;
 
-       if (!lqr->lqr_dirty) {
+       if (!test_bit(LQ_DIRTY, &lqr->lqr_flags)) {
                LASSERT(lqr->lqr_pool.op_size);
                RETURN(0);
        }
 
        /* Do actual allocation. */
-       down_write(&lod->lod_qos.lq_rw_sem);
+       down_write(&ltd->ltd_qos.lq_rw_sem);
 
        /*
         * Check again. While we were sleeping on @lq_rw_sem something could
         * change.
         */
-       if (!lqr->lqr_dirty) {
+       if (!test_bit(LQ_DIRTY, &lqr->lqr_flags)) {
                LASSERT(lqr->lqr_pool.op_size);
-               up_write(&lod->lod_qos.lq_rw_sem);
+               up_write(&ltd->ltd_qos.lq_rw_sem);
                RETURN(0);
        }
 
@@ -487,33 +287,33 @@ static int lod_qos_calc_rr(struct lod_device *lod, struct ost_pool *src_pool,
           deleting from the pool. The lq_rw_sem insures that nobody else
           is reading. */
        lqr->lqr_pool.op_count = real_count;
-       rc = lod_ost_pool_extend(&lqr->lqr_pool, real_count);
+       rc = tgt_pool_extend(&lqr->lqr_pool, real_count);
        if (rc) {
-               up_write(&lod->lod_qos.lq_rw_sem);
+               up_write(&ltd->ltd_qos.lq_rw_sem);
                RETURN(rc);
        }
        for (i = 0; i < lqr->lqr_pool.op_count; i++)
                lqr->lqr_pool.op_array[i] = LOV_QOS_EMPTY;
 
-       /* Place all the OSTs from 1 OSS at the same time. */
+       /* Place all the tgts from 1 svr at the same time. */
        placed = 0;
-       list_for_each_entry(oss, &lod->lod_qos.lq_svr_list, lsq_svr_list) {
+       list_for_each_entry(svr, &ltd->ltd_qos.lq_svr_list, lsq_svr_list) {
                int j = 0;
 
                for (i = 0; i < lqr->lqr_pool.op_count; i++) {
                        int next;
 
-                       if (!cfs_bitmap_check(lod->lod_ost_bitmap,
-                                               src_pool->op_array[i]))
+                       if (!test_bit(src_pool->op_array[i],
+                                     ltd->ltd_tgt_bitmap))
                                continue;
 
-                       ost = OST_TGT(lod,src_pool->op_array[i]);
-                       LASSERT(ost && ost->ltd_ost);
-                       if (ost->ltd_qos.ltq_svr != oss)
+                       tgt = LTD_TGT(ltd, src_pool->op_array[i]);
+                       LASSERT(tgt && tgt->ltd_tgt);
+                       if (tgt->ltd_qos.ltq_svr != svr)
                                continue;
 
-                       /* Evenly space these OSTs across arrayspace */
-                       next = j * lqr->lqr_pool.op_count / oss->lsq_tgt_count;
+                       /* Evenly space these tgts across arrayspace */
+                       next = j * lqr->lqr_pool.op_count / svr->lsq_tgt_count;
                        while (lqr->lqr_pool.op_array[next] != LOV_QOS_EMPTY)
                                next = (next + 1) % lqr->lqr_pool.op_count;
 
@@ -523,19 +323,19 @@ static int lod_qos_calc_rr(struct lod_device *lod, struct ost_pool *src_pool,
                }
        }
 
-       lqr->lqr_dirty = 0;
-       up_write(&lod->lod_qos.lq_rw_sem);
+       clear_bit(LQ_DIRTY, &lqr->lqr_flags);
+       up_write(&ltd->ltd_qos.lq_rw_sem);
 
        if (placed != real_count) {
                /* This should never happen */
-               LCONSOLE_ERROR_MSG(0x14e, "Failed to place all OSTs in the "
+               LCONSOLE_ERROR_MSG(0x14e, "Failed to place all tgts in the "
                                   "round-robin list (%d of %d).\n",
                                   placed, real_count);
                for (i = 0; i < lqr->lqr_pool.op_count; i++) {
-                       LCONSOLE(D_WARNING, "rr #%d ost idx=%d\n", i,
+                       LCONSOLE(D_WARNING, "rr #%d tgt idx=%d\n", i,
                                 lqr->lqr_pool.op_array[i]);
                }
-               lqr->lqr_dirty = 1;
+               set_bit(LQ_DIRTY, &lqr->lqr_flags);
                RETURN(-EAGAIN);
        }
 
@@ -580,12 +380,12 @@ static struct dt_object *lod_qos_declare_object_on(const struct lu_env *env,
        ENTRY;
 
        LASSERT(d);
-       LASSERT(ost_idx < d->lod_osts_size);
+       LASSERT(ost_idx < d->lod_ost_descs.ltd_tgts_size);
        ost = OST_TGT(d,ost_idx);
        LASSERT(ost);
-       LASSERT(ost->ltd_ost);
+       LASSERT(ost->ltd_tgt);
 
-       nd = &ost->ltd_ost->dd_lu_dev;
+       nd = &ost->ltd_tgt->dd_lu_dev;
 
        /*
         * allocate anonymous object with zero fid, real fid
@@ -594,7 +394,7 @@ static struct dt_object *lod_qos_declare_object_on(const struct lu_env *env,
         */
        o = lu_object_anon(env, nd, NULL);
        if (IS_ERR(o))
-               GOTO(out, dt = ERR_PTR(PTR_ERR(o)));
+               GOTO(out, dt = ERR_CAST(o));
 
        n = lu_object_locate(o->lo_header, nd->ld_type);
        if (unlikely(n == NULL)) {
@@ -638,7 +438,7 @@ static int min_stripe_count(__u32 stripe_count, int flags)
 #define LOV_CREATE_RESEED_MIN  2000
 
 /**
- * Initialize temporary OST-in-use array.
+ * Initialize temporary tgt-in-use array.
  *
  * Allocate or extend the array used to mark targets already assigned to a new
  * striping so they are not used more than once.
@@ -649,7 +449,7 @@ static int min_stripe_count(__u32 stripe_count, int flags)
  * \retval 0           on success
  * \retval -ENOMEM     on error
  */
-static inline int lod_qos_ost_in_use_clear(const struct lu_env *env,
+static inline int lod_qos_tgt_in_use_clear(const struct lu_env *env,
                                           __u32 stripes)
 {
        struct lod_thread_info *info = lod_env_info(env);
@@ -657,7 +457,7 @@ static inline int lod_qos_ost_in_use_clear(const struct lu_env *env,
        if (info->lti_ea_store_size < sizeof(int) * stripes)
                lod_ea_store_resize(info, stripes * sizeof(int));
        if (info->lti_ea_store_size < sizeof(int) * stripes) {
-               CERROR("can't allocate memory for ost-in-use array\n");
+               CERROR("can't allocate memory for tgt-in-use array\n");
                return -ENOMEM;
        }
        memset(info->lti_ea_store, -1, sizeof(int) * stripes);
@@ -668,43 +468,44 @@ static inline int lod_qos_ost_in_use_clear(const struct lu_env *env,
  * Remember a target in the array of used targets.
  *
  * Mark the given target as used for a new striping being created. The status
- * of an OST in a striping can be checked with lod_qos_is_ost_used().
+ * of an tgt in a striping can be checked with lod_qos_is_tgt_used().
  *
  * \param[in] env      execution environment for this thread
  * \param[in] idx      index in the array
- * \param[in] ost      OST target index to mark as used
+ * \param[in] tgt_idx  target index to mark as used
  */
-static inline void lod_qos_ost_in_use(const struct lu_env *env,
-                                     int idx, int ost)
+static inline void lod_qos_tgt_in_use(const struct lu_env *env,
+                                     int idx, int tgt_idx)
 {
        struct lod_thread_info *info = lod_env_info(env);
-       int *osts = info->lti_ea_store;
+       int *tgts = info->lti_ea_store;
 
        LASSERT(info->lti_ea_store_size >= idx * sizeof(int));
-       osts[idx] = ost;
+       tgts[idx] = tgt_idx;
 }
 
 /**
- * Check is OST used in a striping.
+ * Check is tgt used in a striping.
  *
- * Checks whether OST with the given index is marked as used in the temporary
- * array (see lod_qos_ost_in_use()).
+ * Checks whether tgt with the given index is marked as used in the temporary
+ * array (see lod_qos_tgt_in_use()).
  *
  * \param[in] env      execution environment for this thread
- * \param[in] ost      OST target index to check
+ * \param[in] tgt_idx  target index to check
  * \param[in] stripes  the number of items used in the array already
  *
  * \retval 0           not used
  * \retval 1           used
  */
-static int lod_qos_is_ost_used(const struct lu_env *env, int ost, __u32 stripes)
+static int lod_qos_is_tgt_used(const struct lu_env *env, int tgt_idx,
+                              __u32 stripes)
 {
        struct lod_thread_info *info = lod_env_info(env);
-       int *osts = info->lti_ea_store;
+       int *tgts = info->lti_ea_store;
        __u32 j;
 
        for (j = 0; j < stripes; j++) {
-               if (osts[j] == ost)
+               if (tgts[j] == tgt_idx)
                        return 1;
        }
        return 0;
@@ -778,7 +579,7 @@ static inline bool lod_should_avoid_ost(struct lod_object *lo,
        bool used = false;
        int i;
 
-       if (!cfs_bitmap_check(lod->lod_ost_bitmap, index)) {
+       if (!test_bit(index, lod->lod_ost_bitmap)) {
                QOS_DEBUG("OST%d: been used in conflicting mirror component\n",
                          index);
                return true;
@@ -806,7 +607,7 @@ static inline bool lod_should_avoid_ost(struct lod_object *lo,
                return false;
 
        /* if the OSS has been used, check whether the OST has been used */
-       if (!cfs_bitmap_check(lag->lag_ost_avoid_bitmap, index))
+       if (!test_bit(index, lag->lag_ost_avoid_bitmap))
                used = false;
        else
                QOS_DEBUG("OST%d: been used in conflicting mirror component\n",
@@ -817,21 +618,23 @@ static inline bool lod_should_avoid_ost(struct lod_object *lo,
 static int lod_check_and_reserve_ost(const struct lu_env *env,
                                     struct lod_object *lo,
                                     struct lod_layout_component *lod_comp,
-                                    struct obd_statfs *sfs, __u32 ost_idx,
-                                    __u32 speed, __u32 *s_idx,
+                                    __u32 ost_idx, __u32 speed, __u32 *s_idx,
                                     struct dt_object **stripe,
                                     __u32 *ost_indices,
                                     struct thandle *th,
-                                    bool *overstriped)
+                                    bool *overstriped,
+                                    __u64 reserve)
 {
        struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct lod_avoid_guide *lag = &lod_env_info(env)->lti_avoid;
+       struct lu_tgt_desc *ost = OST_TGT(lod, ost_idx);
        struct dt_object   *o;
        __u32 stripe_idx = *s_idx;
        int rc;
+
        ENTRY;
 
-       rc = lod_statfs_and_check(env, lod, ost_idx, sfs);
+       rc = lod_statfs_and_check(env, lod, &lod->lod_ost_descs, ost, reserve);
        if (rc)
                RETURN(rc);
 
@@ -839,7 +642,7 @@ static int lod_check_and_reserve_ost(const struct lu_env *env,
         * We expect number of precreated objects in f_ffree at
         * the first iteration, skip OSPs with no objects ready
         */
-       if (sfs->os_fprecreated == 0 && speed == 0) {
+       if (ost->ltd_statfs.os_fprecreated == 0 && speed == 0) {
                QOS_DEBUG("#%d: precreation is empty\n", ost_idx);
                RETURN(rc);
        }
@@ -847,7 +650,7 @@ static int lod_check_and_reserve_ost(const struct lu_env *env,
        /*
         * try to use another OSP if this one is degraded
         */
-       if (sfs->os_state & OS_STATE_DEGRADED && speed < 2) {
+       if (ost->ltd_statfs.os_state & OS_STATFS_DEGRADED && speed < 2) {
                QOS_DEBUG("#%d: degraded\n", ost_idx);
                RETURN(rc);
        }
@@ -867,13 +670,13 @@ static int lod_check_and_reserve_ost(const struct lu_env *env,
         * for the first and second time.
         */
        if (speed < 2 && lod_should_avoid_ost(lo, lag, ost_idx)) {
-               QOS_DEBUG("iter %d: OST%d used by conflicting mirror "
-                         "component\n", speed, ost_idx);
+               QOS_DEBUG("iter %d: OST%d used by conflicting mirror component\n",
+                         speed, ost_idx);
                RETURN(rc);
        }
 
        /* do not put >1 objects on a single OST, except for overstriping */
-       if (lod_qos_is_ost_used(env, ost_idx, stripe_idx)) {
+       if (lod_qos_is_tgt_used(env, ost_idx, stripe_idx)) {
                if (lod_comp->llc_pattern & LOV_PATTERN_OVERSTRIPING)
                        *overstriped = true;
                else
@@ -892,7 +695,7 @@ static int lod_check_and_reserve_ost(const struct lu_env *env,
         * We've successfully declared (reserved) an object
         */
        lod_avoid_update(lo, lag);
-       lod_qos_ost_in_use(env, stripe_idx, ost_idx);
+       lod_qos_tgt_in_use(env, stripe_idx, ost_idx);
        stripe[stripe_idx] = o;
        ost_indices[stripe_idx] = ost_idx;
        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_LOV_CREATE_RACE, 2);
@@ -928,17 +731,17 @@ static int lod_check_and_reserve_ost(const struct lu_env *env,
  * \retval -ENOSPC     if not enough OSTs are found
  * \retval negative    negated errno for other failures
  */
-static int lod_alloc_rr(const struct lu_env *env, struct lod_object *lo,
-                       struct dt_object **stripe, __u32 *ost_indices,
-                       int flags, struct thandle *th, int comp_idx)
+static int lod_ost_alloc_rr(const struct lu_env *env, struct lod_object *lo,
+                           struct dt_object **stripe, __u32 *ost_indices,
+                           int flags, struct thandle *th, int comp_idx,
+                           __u64 reserve)
 {
        struct lod_layout_component *lod_comp;
        struct lod_device *m = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
-       struct obd_statfs *sfs = &lod_env_info(env)->lti_osfs;
        struct pool_desc  *pool = NULL;
-       struct ost_pool   *osts;
+       struct lu_tgt_pool *osts;
        struct lu_qos_rr *lqr;
-       unsigned int    i, array_idx;
+       unsigned int i, array_idx;
        __u32 ost_start_idx_temp;
        __u32 stripe_idx = 0;
        __u32 stripe_count, stripe_count_min, ost_idx;
@@ -960,19 +763,19 @@ static int lod_alloc_rr(const struct lu_env *env, struct lod_object *lo,
                osts = &(pool->pool_obds);
                lqr = &(pool->pool_rr);
        } else {
-               osts = &(m->lod_pool_info);
-               lqr = &(m->lod_qos.lq_rr);
+               osts = &m->lod_ost_descs.ltd_tgt_pool;
+               lqr = &(m->lod_ost_descs.ltd_qos.lq_rr);
        }
 
-       rc = lod_qos_calc_rr(m, osts, lqr);
+       rc = lod_qos_calc_rr(m, &m->lod_ost_descs, osts, lqr);
        if (rc)
                GOTO(out, rc);
 
-       rc = lod_qos_ost_in_use_clear(env, stripe_count);
+       rc = lod_qos_tgt_in_use_clear(env, stripe_count);
        if (rc)
                GOTO(out, rc);
 
-       down_read(&m->lod_qos.lq_rw_sem);
+       down_read(&m->lod_ost_descs.ltd_qos.lq_rw_sem);
        spin_lock(&lqr->lqr_alloc);
        if (--lqr->lqr_start_count <= 0) {
                lqr->lqr_start_idx = prandom_u32_max(osts->op_count);
@@ -1014,7 +817,7 @@ repeat_find:
                          stripe_idx, array_idx, ost_idx);
 
                if ((ost_idx == LOV_QOS_EMPTY) ||
-                   !cfs_bitmap_check(m->lod_ost_bitmap, ost_idx))
+                   !test_bit(ost_idx, m->lod_ost_bitmap))
                        continue;
 
                /* Fail Check before osc_precreate() is called
@@ -1023,9 +826,10 @@ repeat_find:
                        continue;
 
                spin_unlock(&lqr->lqr_alloc);
-               rc = lod_check_and_reserve_ost(env, lo, lod_comp, sfs, ost_idx,
+               rc = lod_check_and_reserve_ost(env, lo, lod_comp, ost_idx,
                                               speed, &stripe_idx, stripe,
-                                              ost_indices, th, &overstriped);
+                                              ost_indices, th, &overstriped,
+                                              reserve);
                spin_lock(&lqr->lqr_alloc);
 
                if (rc != 0 && OST_TGT(m, ost_idx)->ltd_connecting)
@@ -1041,7 +845,7 @@ repeat_find:
        }
 
        spin_unlock(&lqr->lqr_alloc);
-       up_read(&m->lod_qos.lq_rw_sem);
+       up_read(&m->lod_ost_descs.ltd_qos.lq_rw_sem);
 
        /* If there are enough OSTs, a component with overstriping requested
         * will not actually end up overstriped.  The comp should reflect this.
@@ -1071,6 +875,203 @@ out:
        RETURN(rc);
 }
 
+static int
+lod_qos_mdt_in_use_init(const struct lu_env *env,
+                       const struct lu_tgt_descs *ltd,
+                       u32 stripe_idx, u32 stripe_count,
+                       const struct lu_tgt_pool *pool,
+                       struct dt_object **stripes)
+{
+       u32 mdt_idx;
+       struct lu_tgt_desc *mdt;
+       int i, j;
+       int rc;
+
+       rc = lod_qos_tgt_in_use_clear(env, stripe_count);
+       if (rc)
+               return rc;
+
+       /* if stripe_idx > 1, we are splitting directory, mark existing stripes
+        * in_use. Because for either split or creation, stripe 0 is local,
+        * don't mark it in use.
+        */
+       for (i = 1; i < stripe_idx; i++) {
+               LASSERT(stripes[i]);
+               for (j = 0; j < pool->op_count; j++) {
+                       mdt_idx = pool->op_array[j];
+
+                       if (!test_bit(mdt_idx, ltd->ltd_tgt_bitmap))
+                               continue;
+
+                       mdt = LTD_TGT(ltd, mdt_idx);
+                       if (&mdt->ltd_tgt->dd_lu_dev ==
+                           stripes[i]->do_lu.lo_dev)
+                               lod_qos_tgt_in_use(env, i, mdt_idx);
+               }
+       }
+
+       return 0;
+}
+
+/**
+ * Allocate a striping using round-robin algorithm.
+ *
+ * Allocates a new striping using round-robin algorithm. The function refreshes
+ * all the internal structures (statfs cache, array of available remote MDTs
+ * sorted with regard to MDS, etc). The number of stripes required is taken from
+ * the object (must be prepared by the caller). The caller should ensure nobody
+ * else is trying to create a striping on the object in parallel. All the
+ * internal structures (like pools, etc) are protected and no additional locking
+ * is required. The function succeeds even if a single stripe is allocated.
+ *
+ * \param[in] env              execution environment for this thread
+ * \param[in] lo               LOD object
+ * \param[out] stripes         striping created
+ *
+ * \retval positive    stripe objects allocated, including the first stripe
+ *                     allocated outside
+ * \retval -ENOSPC     if not enough MDTs are found
+ * \retval negative    negated errno for other failures
+ */
+int lod_mdt_alloc_rr(const struct lu_env *env, struct lod_object *lo,
+                    struct dt_object **stripes, u32 stripe_idx,
+                    u32 stripe_count)
+{
+       struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
+       struct lu_tgt_descs *ltd = &lod->lod_mdt_descs;
+       struct lu_tgt_pool *pool;
+       struct lu_qos_rr *lqr;
+       struct lu_tgt_desc *mdt;
+       struct lu_object_conf conf = { .loc_flags = LOC_F_NEW };
+       struct lu_fid fid = { 0 };
+       struct dt_object *dto;
+       unsigned int pool_idx;
+       unsigned int i;
+       u32 saved_idx = stripe_idx;
+       u32 start_mdt;
+       u32 mdt_idx;
+       bool use_degraded = false;
+       int tgt_connecting = 0;
+       int rc;
+
+       ENTRY;
+
+       pool = &ltd->ltd_tgt_pool;
+       lqr = &ltd->ltd_qos.lq_rr;
+       rc = lod_qos_calc_rr(lod, ltd, pool, lqr);
+       if (rc)
+               RETURN(rc);
+
+       rc = lod_qos_mdt_in_use_init(env, ltd, stripe_idx, stripe_count, pool,
+                                    stripes);
+       if (rc)
+               RETURN(rc);
+
+       down_read(&ltd->ltd_qos.lq_rw_sem);
+       spin_lock(&lqr->lqr_alloc);
+       if (--lqr->lqr_start_count <= 0) {
+               lqr->lqr_start_idx = prandom_u32_max(pool->op_count);
+               lqr->lqr_start_count =
+                       (LOV_CREATE_RESEED_MIN / max(pool->op_count, 1U) +
+                        LOV_CREATE_RESEED_MULT) * max(pool->op_count, 1U);
+       } else if (stripe_count - 1 >= pool->op_count ||
+                  lqr->lqr_start_idx > pool->op_count) {
+               /* If we have allocated from all of the tgts, slowly
+                * precess the next start if the tgt/stripe count isn't
+                * already doing this for us. */
+               lqr->lqr_start_idx %= pool->op_count;
+               if (stripe_count - 1 > 1 &&
+                   (pool->op_count % (stripe_count - 1)) != 1)
+                       ++lqr->lqr_offset_idx;
+       }
+       start_mdt = lqr->lqr_start_idx;
+
+repeat_find:
+       QOS_DEBUG("want=%d start_idx=%d start_count=%d offset=%d active=%d count=%d\n",
+                 stripe_count - 1, lqr->lqr_start_idx, lqr->lqr_start_count,
+                 lqr->lqr_offset_idx, pool->op_count, pool->op_count);
+
+       for (i = 0; i < pool->op_count && stripe_idx < stripe_count; i++) {
+               pool_idx = (lqr->lqr_start_idx + lqr->lqr_offset_idx) %
+                           pool->op_count;
+               ++lqr->lqr_start_idx;
+               mdt_idx = lqr->lqr_pool.op_array[pool_idx];
+               mdt = LTD_TGT(ltd, mdt_idx);
+
+               QOS_DEBUG("#%d strt %d act %d strp %d ary %d idx %d\n",
+                         i, lqr->lqr_start_idx, /* XXX: active*/ 0,
+                         stripe_idx, pool_idx, mdt_idx);
+
+               if (mdt_idx == LOV_QOS_EMPTY ||
+                   !test_bit(mdt_idx, ltd->ltd_tgt_bitmap))
+                       continue;
+
+               /* do not put >1 objects on one MDT */
+               if (lod_qos_is_tgt_used(env, mdt_idx, stripe_idx))
+                       continue;
+
+               rc = lod_is_tgt_usable(ltd, mdt);
+               if (rc) {
+                       if (mdt->ltd_connecting)
+                               tgt_connecting = 1;
+                       continue;
+               }
+
+               /* try to use another OSP if this one is degraded */
+               if (mdt->ltd_statfs.os_state & OS_STATFS_DEGRADED &&
+                   !use_degraded) {
+                       QOS_DEBUG("#%d: degraded\n", mdt_idx);
+                       continue;
+               }
+               spin_unlock(&lqr->lqr_alloc);
+
+               rc = dt_fid_alloc(env, mdt->ltd_tgt, &fid, NULL, NULL);
+               if (rc < 0) {
+                       QOS_DEBUG("#%d: alloc FID failed: %dl\n", mdt_idx, rc);
+                       spin_lock(&lqr->lqr_alloc);
+                       continue;
+               }
+
+               dto = dt_locate_at(env, mdt->ltd_tgt, &fid,
+                               lo->ldo_obj.do_lu.lo_dev->ld_site->ls_top_dev,
+                               &conf);
+
+               spin_lock(&lqr->lqr_alloc);
+               if (IS_ERR(dto)) {
+                       QOS_DEBUG("can't alloc stripe on #%u: %d\n",
+                                 mdt->ltd_index, (int) PTR_ERR(dto));
+
+                       if (mdt->ltd_connecting)
+                               tgt_connecting = 1;
+                       continue;
+               }
+
+               lod_qos_tgt_in_use(env, stripe_idx, mdt_idx);
+               stripes[stripe_idx++] = dto;
+       }
+
+       if (!use_degraded && stripe_idx < stripe_count) {
+               /* Try again, allowing slower MDTs */
+               use_degraded = true;
+               lqr->lqr_start_idx = start_mdt;
+
+               tgt_connecting = 0;
+               goto repeat_find;
+       }
+       spin_unlock(&lqr->lqr_alloc);
+       up_read(&ltd->ltd_qos.lq_rw_sem);
+
+       if (stripe_idx > saved_idx)
+               /* at least one stripe is allocated */
+               RETURN(stripe_idx);
+
+       /* nobody provided us with a single object */
+       if (tgt_connecting)
+               RETURN(-EINPROGRESS);
+
+       RETURN(-ENOSPC);
+}
+
 /**
  * Allocate a specific striping layout on a user defined set of OSTs.
  *
@@ -1098,11 +1099,10 @@ out:
  */
 static int lod_alloc_ost_list(const struct lu_env *env, struct lod_object *lo,
                              struct dt_object **stripe, __u32 *ost_indices,
-                             struct thandle *th, int comp_idx)
+                             struct thandle *th, int comp_idx, __u64 reserve)
 {
        struct lod_layout_component *lod_comp;
        struct lod_device       *m = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
-       struct obd_statfs       *sfs = &lod_env_info(env)->lti_osfs;
        struct dt_object        *o;
        unsigned int            array_idx = 0;
        int                     stripe_count = 0;
@@ -1116,7 +1116,7 @@ static int lod_alloc_ost_list(const struct lu_env *env, struct lod_object *lo,
        LASSERT(lod_comp->llc_ostlist.op_array);
        LASSERT(lod_comp->llc_ostlist.op_count);
 
-       rc = lod_qos_ost_in_use_clear(env, lod_comp->llc_stripe_count);
+       rc = lod_qos_tgt_in_use_clear(env, lod_comp->llc_stripe_count);
        if (rc < 0)
                RETURN(rc);
 
@@ -1142,7 +1142,7 @@ static int lod_alloc_ost_list(const struct lu_env *env, struct lod_object *lo,
             i++, array_idx = (array_idx + 1) % lod_comp->llc_stripe_count) {
                __u32 ost_idx = lod_comp->llc_ostlist.op_array[array_idx];
 
-               if (!cfs_bitmap_check(m->lod_ost_bitmap, ost_idx)) {
+               if (!test_bit(ost_idx, m->lod_ost_bitmap)) {
                        rc = -ENODEV;
                        break;
                }
@@ -1150,13 +1150,15 @@ static int lod_alloc_ost_list(const struct lu_env *env, struct lod_object *lo,
                /* do not put >1 objects on a single OST, except for
                 * overstriping
                 */
-               if (lod_qos_is_ost_used(env, ost_idx, stripe_count) &&
+               if (lod_qos_is_tgt_used(env, ost_idx, stripe_count) &&
                    !(lod_comp->llc_pattern & LOV_PATTERN_OVERSTRIPING)) {
                        rc = -EINVAL;
                        break;
                }
 
-               rc = lod_statfs_and_check(env, m, ost_idx, sfs);
+               rc = lod_statfs_and_check(env, m, &m->lod_ost_descs,
+                                         LTD_TGT(&m->lod_ost_descs, ost_idx),
+                                         reserve);
                if (rc < 0) /* this OSP doesn't feel well */
                        break;
 
@@ -1172,7 +1174,7 @@ static int lod_alloc_ost_list(const struct lu_env *env, struct lod_object *lo,
                /*
                 * We've successfully declared (reserved) an object
                 */
-               lod_qos_ost_in_use(env, stripe_count, ost_idx);
+               lod_qos_tgt_in_use(env, stripe_count, ost_idx);
                stripe[stripe_count] = o;
                ost_indices[stripe_count] = ost_idx;
                stripe_count++;
@@ -1207,20 +1209,22 @@ static int lod_alloc_ost_list(const struct lu_env *env, struct lod_object *lo,
  * \retval -EINVAL     requested offset is invalid
  * \retval negative    errno on failure
  */
-static int lod_alloc_specific(const struct lu_env *env, struct lod_object *lo,
-                             struct dt_object **stripe, __u32 *ost_indices,
-                             int flags, struct thandle *th, int comp_idx)
+static int lod_ost_alloc_specific(const struct lu_env *env,
+                                 struct lod_object *lo,
+                                 struct dt_object **stripe, __u32 *ost_indices,
+                                 int flags, struct thandle *th, int comp_idx,
+                                 __u64 reserve)
 {
        struct lod_layout_component *lod_comp;
        struct lod_device *m = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
-       struct obd_statfs *sfs = &lod_env_info(env)->lti_osfs;
        struct dt_object *o;
+       struct lu_tgt_desc *tgt;
        __u32 ost_idx;
        unsigned int i, array_idx, ost_count;
        int rc, stripe_num = 0;
        int speed = 0;
-       struct pool_desc  *pool = NULL;
-       struct ost_pool   *osts;
+       struct pool_desc *pool = NULL;
+       struct lu_tgt_pool *osts;
        int stripes_per_ost = 1;
        bool overstriped = false;
        ENTRY;
@@ -1228,7 +1232,7 @@ static int lod_alloc_specific(const struct lu_env *env, struct lod_object *lo,
        LASSERT(lo->ldo_comp_cnt > comp_idx && lo->ldo_comp_entries != NULL);
        lod_comp = &lo->ldo_comp_entries[comp_idx];
 
-       rc = lod_qos_ost_in_use_clear(env, lod_comp->llc_stripe_count);
+       rc = lod_qos_tgt_in_use_clear(env, lod_comp->llc_stripe_count);
        if (rc)
                GOTO(out, rc);
 
@@ -1239,7 +1243,7 @@ static int lod_alloc_specific(const struct lu_env *env, struct lod_object *lo,
                down_read(&pool_tgt_rw_sem(pool));
                osts = &(pool->pool_obds);
        } else {
-               osts = &(m->lod_pool_info);
+               osts = &m->lod_ost_descs.ltd_tgt_pool;
        }
 
        ost_count = osts->op_count;
@@ -1268,7 +1272,7 @@ repeat_find:
                        i++, array_idx = (array_idx + 1) % ost_count) {
                ost_idx = osts->op_array[array_idx];
 
-               if (!cfs_bitmap_check(m->lod_ost_bitmap, ost_idx))
+               if (!test_bit(ost_idx, m->lod_ost_bitmap))
                        continue;
 
                /* Fail Check before osc_precreate() is called
@@ -1280,7 +1284,7 @@ repeat_find:
                 * do not put >1 objects on a single OST, except for
                 * overstriping, where it is intended
                 */
-               if (lod_qos_is_ost_used(env, ost_idx, stripe_num)) {
+               if (lod_qos_is_tgt_used(env, ost_idx, stripe_num)) {
                        if (lod_comp->llc_pattern & LOV_PATTERN_OVERSTRIPING)
                                overstriped = true;
                        else
@@ -1294,13 +1298,16 @@ repeat_find:
                    lod_comp_is_ost_used(env, lo, ost_idx))
                        continue;
 
+               tgt = LTD_TGT(&m->lod_ost_descs, ost_idx);
+
                /* Drop slow OSCs if we can, but not for requested start idx.
                 *
                 * This means "if OSC is slow and it is not the requested
                 * start OST, then it can be skipped, otherwise skip it only
                 * if it is inactive/recovering/out-of-space." */
 
-               rc = lod_statfs_and_check(env, m, ost_idx, sfs);
+               rc = lod_statfs_and_check(env, m, &m->lod_ost_descs,
+                                         tgt, reserve);
                if (rc) {
                        /* this OSP doesn't feel well */
                        continue;
@@ -1311,7 +1318,7 @@ repeat_find:
                 * iteration.  Skip OSPs with no objects ready.  Don't apply
                 * this logic to OST specified with stripe_offset.
                 */
-               if (i != 0 && sfs->os_fprecreated == 0 && speed == 0)
+               if (i && !tgt->ltd_statfs.os_fprecreated && !speed)
                        continue;
 
                o = lod_qos_declare_object_on(env, m, ost_idx, th);
@@ -1324,7 +1331,7 @@ repeat_find:
                /*
                 * We've successfully declared (reserved) an object
                 */
-               lod_qos_ost_in_use(env, stripe_num, ost_idx);
+               lod_qos_tgt_in_use(env, stripe_num, ost_idx);
                stripe[stripe_num] = o;
                ost_indices[stripe_num] = ost_idx;
                stripe_num++;
@@ -1365,36 +1372,6 @@ out:
 }
 
 /**
- * Check whether QoS allocation should be used.
- *
- * A simple helper to decide when QoS allocation should be used:
- * if it's just a single available target or the used space is
- * evenly distributed among the targets at the moment, then QoS
- * allocation algorithm should not be used.
- *
- * \param[in] lod      LOD device
- *
- * \retval 0           should not be used
- * \retval 1           should be used
- */
-static inline int lod_qos_is_usable(struct lod_device *lod)
-{
-#ifdef FORCE_QOS
-       /* to be able to debug QoS code */
-       return 1;
-#endif
-
-       /* Detect -EAGAIN early, before expensive lock is taken. */
-       if (!lod->lod_qos.lq_dirty && lod->lod_qos.lq_same_space)
-               return 0;
-
-       if (lod->lod_desc.ld_active_tgt_count < 2)
-               return 0;
-
-       return 1;
-}
-
-/**
  * Allocate a striping using an algorithm with weights.
  *
  * The function allocates OST objects to create a striping. The algorithm
@@ -1429,19 +1406,19 @@ static inline int lod_qos_is_usable(struct lod_device *lod)
  * \retval -EINVAL     requested OST index is invalid
  * \retval negative    errno on failure
  */
-static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
-                        struct dt_object **stripe, __u32 *ost_indices,
-                        int flags, struct thandle *th, int comp_idx)
+static int lod_ost_alloc_qos(const struct lu_env *env, struct lod_object *lo,
+                            struct dt_object **stripe, __u32 *ost_indices,
+                            int flags, struct thandle *th, int comp_idx,
+                            __u64 reserve)
 {
        struct lod_layout_component *lod_comp;
        struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
-       struct obd_statfs *sfs = &lod_env_info(env)->lti_osfs;
        struct lod_avoid_guide *lag = &lod_env_info(env)->lti_avoid;
        struct lod_tgt_desc *ost;
        struct dt_object *o;
        __u64 total_weight = 0;
        struct pool_desc *pool = NULL;
-       struct ost_pool *osts;
+       struct lu_tgt_pool *osts;
        unsigned int i;
        __u32 nfound, good_osts, stripe_count, stripe_count_min;
        bool overstriped = false;
@@ -1463,11 +1440,11 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                down_read(&pool_tgt_rw_sem(pool));
                osts = &(pool->pool_obds);
        } else {
-               osts = &(lod->lod_pool_info);
+               osts = &lod->lod_ost_descs.ltd_tgt_pool;
        }
 
        /* Detect -EAGAIN early, before expensive lock is taken. */
-       if (!lod_qos_is_usable(lod))
+       if (!ltd_qos_is_usable(&lod->lod_ost_descs))
                GOTO(out_nolock, rc = -EAGAIN);
 
        if (lod_comp->llc_pattern & LOV_PATTERN_OVERSTRIPING)
@@ -1475,49 +1452,51 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                        (lod_comp->llc_stripe_count - 1)/osts->op_count + 1;
 
        /* Do actual allocation, use write lock here. */
-       down_write(&lod->lod_qos.lq_rw_sem);
+       down_write(&lod->lod_ost_descs.ltd_qos.lq_rw_sem);
 
        /*
         * Check again, while we were sleeping on @lq_rw_sem things could
         * change.
         */
-       if (!lod_qos_is_usable(lod))
+       if (!ltd_qos_is_usable(&lod->lod_ost_descs))
                GOTO(out, rc = -EAGAIN);
 
-       rc = lod_qos_calc_ppo(lod);
+       rc = ltd_qos_penalties_calc(&lod->lod_ost_descs);
        if (rc)
                GOTO(out, rc);
 
-       rc = lod_qos_ost_in_use_clear(env, lod_comp->llc_stripe_count);
+       rc = lod_qos_tgt_in_use_clear(env, lod_comp->llc_stripe_count);
        if (rc)
                GOTO(out, rc);
 
        good_osts = 0;
        /* Find all the OSTs that are valid stripe candidates */
        for (i = 0; i < osts->op_count; i++) {
-               if (!cfs_bitmap_check(lod->lod_ost_bitmap, osts->op_array[i]))
+               if (!test_bit(osts->op_array[i], lod->lod_ost_bitmap))
                        continue;
 
                ost = OST_TGT(lod, osts->op_array[i]);
                ost->ltd_qos.ltq_usable = 0;
 
-               rc = lod_statfs_and_check(env, lod, osts->op_array[i], sfs);
+               rc = lod_statfs_and_check(env, lod, &lod->lod_ost_descs,
+                                         ost, reserve);
                if (rc) {
                        /* this OSP doesn't feel well */
                        continue;
                }
 
-               if (sfs->os_state & OS_STATE_DEGRADED)
+               if (ost->ltd_statfs.os_state & OS_STATFS_DEGRADED)
                        continue;
 
                /* Fail Check before osc_precreate() is called
-                  so we can only 'fail' single OSC. */
+                * so we can only 'fail' single OSC.
+                */
                if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) &&
                                   osts->op_array[i] == 0)
                        continue;
 
                ost->ltd_qos.ltq_usable = 1;
-               lod_qos_calc_weight(lod, osts->op_array[i]);
+               lu_tgt_qos_weight_calc(ost);
                total_weight += ost->ltd_qos.ltq_weight;
 
                good_osts++;
@@ -1545,7 +1524,8 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                rand = lu_prandom_u64_max(total_weight);
 
                /* On average, this will hit larger-weighted OSTs more often.
-                * 0-weight OSTs will always get used last (only when rand=0) */
+                * 0-weight OSTs will always get used last (only when rand=0)
+                */
                for (i = 0; i < osts->op_count; i++) {
                        __u32 idx = osts->op_array[i];
 
@@ -1575,7 +1555,7 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                            !(lod_comp->llc_pattern & LOV_PATTERN_OVERSTRIPING))
                                continue;
 
-                       if (lod_qos_is_ost_used(env, idx, nfound)) {
+                       if (lod_qos_is_tgt_used(env, idx, nfound)) {
                                if (lod_comp->llc_pattern &
                                    LOV_PATTERN_OVERSTRIPING)
                                        overstriped = true;
@@ -1591,10 +1571,10 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                        }
 
                        lod_avoid_update(lo, lag);
-                       lod_qos_ost_in_use(env, nfound, idx);
+                       lod_qos_tgt_in_use(env, nfound, idx);
                        stripe[nfound] = o;
                        ost_indices[nfound] = idx;
-                       lod_qos_used(lod, osts, idx, &total_weight);
+                       ltd_qos_update(&lod->lod_ost_descs, ost, &total_weight);
                        nfound++;
                        rc = 0;
                        break;
@@ -1623,9 +1603,8 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                }
 
                /* makes sense to rebalance next time */
-               lod->lod_qos.lq_dirty = 1;
-               lod->lod_qos.lq_same_space = 0;
-
+               set_bit(LQ_DIRTY, &lod->lod_ost_descs.ltd_qos.lq_flags);
+               clear_bit(LQ_SAME_SPACE, &lod->lod_ost_descs.ltd_qos.lq_flags);
                rc = -EAGAIN;
        }
 
@@ -1636,7 +1615,7 @@ static int lod_alloc_qos(const struct lu_env *env, struct lod_object *lo,
                lod_comp->llc_pattern &= ~LOV_PATTERN_OVERSTRIPING;
 
 out:
-       up_write(&lod->lod_qos.lq_rw_sem);
+       up_write(&lod->lod_ost_descs.ltd_qos.lq_rw_sem);
 
 out_nolock:
        if (pool != NULL) {
@@ -1649,6 +1628,216 @@ out_nolock:
 }
 
 /**
+ * Allocate a striping using an algorithm with weights.
+ *
+ * The function allocates remote MDT objects to create a striping, the first
+ * object was already allocated on current MDT to ensure master object and
+ * the first object are on the same MDT. The algorithm used is based on weights
+ * (both free space and inodes), and it's trying to ensure the space/inodes are
+ * used evenly by MDTs and MDSs. The striping configuration (# of stripes,
+ * offset, pool) is taken from the object and is prepared by the caller.
+ *
+ * If prepared configuration can't be met due to too few MDTs, then allocation
+ * fails.
+ *
+ * No concurrent allocation is allowed on the object and this must be ensured
+ * by the caller. All the internal structures are protected by the function.
+ *
+ * The algorithm has two steps: find available MDTs and calculate their
+ * weights, then select the MDTs with their weights used as the probability.
+ * An MDT with a higher weight is proportionately more likely to be selected
+ * than one with a lower weight.
+ *
+ * \param[in] env              execution environment for this thread
+ * \param[in] lo               LOD object
+ * \param[in] stripe_idx       starting stripe index to allocate, if it's not
+ *                             0, we are restriping directory
+ * \param[in] stripe_count     total stripe count
+ * \param[out] stripes         striping created
+ *
+ * \retval positive    stripes allocated, and it should be equal to
+ *                     lo->ldo_dir_stripe_count
+ * \retval -EAGAIN     not enough tgts are found for specified stripe count
+ * \retval -EINVAL     requested MDT index is invalid
+ * \retval negative    errno on failure
+ */
+int lod_mdt_alloc_qos(const struct lu_env *env, struct lod_object *lo,
+                     struct dt_object **stripes, u32 stripe_idx,
+                     u32 stripe_count)
+{
+       struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
+       struct lu_tgt_descs *ltd = &lod->lod_mdt_descs;
+       struct lu_object_conf conf = { .loc_flags = LOC_F_NEW };
+       struct lu_fid fid = { 0 };
+       const struct lu_tgt_pool *pool;
+       struct lu_tgt_desc *mdt;
+       struct dt_object *dto;
+       u64 total_weight = 0;
+       u32 saved_idx = stripe_idx;
+       u32 mdt_idx;
+       unsigned int good_mdts;
+       unsigned int i;
+       int rc = 0;
+
+       ENTRY;
+
+       LASSERT(stripe_idx <= stripe_count);
+       if (stripe_idx == stripe_count)
+               RETURN(stripe_count);
+
+       /* use MDT pool in @ltd, once MDT pool is supported in the future, it
+        * can be passed in as argument like OST object allocation.
+        */
+       pool = &ltd->ltd_tgt_pool;
+
+       /* Detect -EAGAIN early, before expensive lock is taken. */
+       if (!ltd_qos_is_usable(ltd))
+               RETURN(-EAGAIN);
+
+       rc = lod_qos_mdt_in_use_init(env, ltd, stripe_idx, stripe_count, pool,
+                                    stripes);
+       if (rc)
+               RETURN(rc);
+
+       /* Do actual allocation, use write lock here. */
+       down_write(&ltd->ltd_qos.lq_rw_sem);
+
+       /*
+        * Check again, while we were sleeping on @lq_rw_sem things could
+        * change.
+        */
+       if (!ltd_qos_is_usable(ltd))
+               GOTO(unlock, rc = -EAGAIN);
+
+       rc = ltd_qos_penalties_calc(ltd);
+       if (rc)
+               GOTO(unlock, rc);
+
+       good_mdts = 0;
+       /* Find all the MDTs that are valid stripe candidates */
+       for (i = 0; i < pool->op_count; i++) {
+               if (!test_bit(pool->op_array[i], ltd->ltd_tgt_bitmap))
+                       continue;
+
+               mdt = LTD_TGT(ltd, pool->op_array[i]);
+               mdt->ltd_qos.ltq_usable = 0;
+
+               rc = lod_is_tgt_usable(ltd, mdt);
+               if (rc)
+                       continue;
+
+               if (mdt->ltd_statfs.os_state & OS_STATFS_DEGRADED)
+                       continue;
+
+               mdt->ltd_qos.ltq_usable = 1;
+               lu_tgt_qos_weight_calc(mdt);
+               total_weight += mdt->ltd_qos.ltq_weight;
+
+               good_mdts++;
+       }
+
+       QOS_DEBUG("found %d good MDTs\n", good_mdts);
+
+       if (good_mdts < stripe_count - stripe_idx)
+               GOTO(unlock, rc = -EAGAIN);
+
+       /* Find enough MDTs with weighted random allocation. */
+       while (stripe_idx < stripe_count) {
+               u64 rand, cur_weight;
+
+               cur_weight = 0;
+               rc = -ENOSPC;
+
+               rand = lu_prandom_u64_max(total_weight);
+
+               /* On average, this will hit larger-weighted MDTs more often.
+                * 0-weight MDT will always get used last (only when rand=0) */
+               for (i = 0; i < pool->op_count; i++) {
+                       int rc2;
+
+                       mdt_idx = pool->op_array[i];
+                       mdt = LTD_TGT(ltd, mdt_idx);
+
+                       if (!mdt->ltd_qos.ltq_usable)
+                               continue;
+
+                       cur_weight += mdt->ltd_qos.ltq_weight;
+
+                       QOS_DEBUG("stripe_count=%d stripe_index=%d cur_weight=%llu rand=%llu total_weight=%llu\n",
+                                 stripe_count, stripe_idx, cur_weight, rand,
+                                 total_weight);
+
+                       if (cur_weight < rand)
+                               continue;
+
+                       QOS_DEBUG("stripe=%d to idx=%d\n",
+                                 stripe_idx, mdt_idx);
+
+                       if (lod_qos_is_tgt_used(env, mdt_idx, stripe_idx))
+                               continue;
+
+                       rc2 = dt_fid_alloc(env, mdt->ltd_tgt, &fid, NULL, NULL);
+                       if (rc2 < 0) {
+                               QOS_DEBUG("can't alloc FID on #%u: %d\n",
+                                         mdt_idx, rc2);
+                               continue;
+                       }
+
+                       conf.loc_flags = LOC_F_NEW;
+                       dto = dt_locate_at(env, mdt->ltd_tgt, &fid,
+                               lo->ldo_obj.do_lu.lo_dev->ld_site->ls_top_dev,
+                               &conf);
+                       if (IS_ERR(dto)) {
+                               QOS_DEBUG("can't alloc stripe on #%u: %d\n",
+                                         mdt_idx, (int) PTR_ERR(dto));
+                               continue;
+                       }
+
+                       lod_qos_tgt_in_use(env, stripe_idx, mdt_idx);
+                       stripes[stripe_idx] = dto;
+                       ltd_qos_update(ltd, mdt, &total_weight);
+                       stripe_idx++;
+                       rc = 0;
+                       break;
+               }
+
+               /* no MDT found on this iteration, give up */
+               if (rc)
+                       break;
+       }
+
+       if (unlikely(stripe_idx != stripe_count)) {
+               /*
+                * when the decision to use weighted algorithm was made
+                * we had enough appropriate OSPs, but this state can
+                * change anytime (no space on MDT, broken connection, etc)
+                * so it's possible OSP won't be able to provide us with
+                * an object due to just changed state
+                */
+               QOS_DEBUG("%s: wanted %d objects, found only %d\n",
+                         lod2obd(lod)->obd_name, stripe_count, stripe_idx);
+               for (i = saved_idx; i < stripe_idx; i++) {
+                       LASSERT(stripes[i] != NULL);
+                       dt_object_put(env, stripes[i]);
+                       stripes[i] = NULL;
+               }
+
+               /* makes sense to rebalance next time */
+               set_bit(LQ_DIRTY, &ltd->ltd_qos.lq_flags);
+               clear_bit(LQ_SAME_SPACE, &ltd->ltd_qos.lq_flags);
+
+               rc = -EAGAIN;
+       } else {
+               rc = stripe_idx;
+       }
+
+unlock:
+       up_write(&ltd->ltd_qos.lq_rw_sem);
+
+       RETURN(rc);
+}
+
+/**
  * Check stripe count the caller can use.
  *
  * For new layouts (no initialized components), check the total size of the
@@ -1661,26 +1850,31 @@ out_nolock:
  *
  * \param[in] lod      LOD device
  * \param[in] lo       The lod_object
+ * \param[in] comp_idx The component id, which the amount of stripes is
+                       calculated for
  * \param[in] stripe_count     count the caller would like to use
  *
  * \retval             the maximum usable stripe count
  */
 __u16 lod_get_stripe_count(struct lod_device *lod, struct lod_object *lo,
-                          __u16 stripe_count, bool overstriping)
+                          int comp_idx, __u16 stripe_count, bool overstriping)
 {
        __u32 max_stripes = LOV_MAX_STRIPE_COUNT_OLD;
        /* max stripe count is based on OSD ea size */
        unsigned int easize = lod->lod_osd_max_easize;
        int i;
 
-
        if (!stripe_count)
-               stripe_count = lod->lod_desc.ld_default_stripe_count;
+               stripe_count =
+                       lod->lod_ost_descs.ltd_lov_desc.ld_default_stripe_count;
        if (!stripe_count)
                stripe_count = 1;
        /* Overstriping allows more stripes than targets */
-       if (stripe_count > lod->lod_desc.ld_active_tgt_count && !overstriping)
-               stripe_count = lod->lod_desc.ld_active_tgt_count;
+       if (stripe_count >
+               lod->lod_ost_descs.ltd_lov_desc.ld_active_tgt_count &&
+           !overstriping)
+               stripe_count =
+                       lod->lod_ost_descs.ltd_lov_desc.ld_active_tgt_count;
 
        if (lo->ldo_is_composite) {
                struct lod_layout_component *lod_comp;
@@ -1693,9 +1887,17 @@ __u16 lod_get_stripe_count(struct lod_device *lod, struct lod_object *lo,
                                lo->ldo_comp_cnt;
 
                for (i = 0; i < lo->ldo_comp_cnt; i++) {
+                       unsigned int stripes;
+
+                       if (i == comp_idx)
+                               continue;
+
                        lod_comp = &lo->ldo_comp_entries[i];
-                       comp_sz = lov_mds_md_size(lod_comp->llc_stripe_count,
-                                                 LOV_MAGIC_V3);
+                       /* Extension comp is never inited - 0 stripes on disk */
+                       stripes = lod_comp->llc_flags & LCME_FL_EXTENSION ? 0 :
+                               lod_comp->llc_stripe_count;
+
+                       comp_sz = lov_mds_md_size(stripes, LOV_MAGIC_V3);
                        total_comp_sz += comp_sz;
                        if (lod_comp->llc_flags & LCME_FL_INIT)
                                init_comp_sz += comp_sz;
@@ -1713,6 +1915,7 @@ __u16 lod_get_stripe_count(struct lod_device *lod, struct lod_object *lo,
        }
 
        max_stripes = lov_mds_md_max_stripe_count(easize, LOV_MAGIC_V3);
+       max_stripes = (max_stripes == 0) ? 0 : max_stripes - 1;
 
        return (stripe_count < max_stripes) ? stripe_count : max_stripes;
 }
@@ -1896,7 +2099,7 @@ int lod_qos_parse_config(const struct lu_env *env, struct lod_object *lo,
 {
        struct lod_layout_component *lod_comp;
        struct lod_device *d = lu2lod_dev(lod2lu_obj(lo)->lo_dev);
-       struct lov_desc *desc = &d->lod_desc;
+       struct lov_desc *desc = &d->lod_ost_descs.ltd_lov_desc;
        struct lov_user_md_v1 *v1 = NULL;
        struct lov_user_md_v3 *v3 = NULL;
        struct lov_comp_md_v1 *comp_v1 = NULL;
@@ -1922,7 +2125,7 @@ int lod_qos_parse_config(const struct lu_env *env, struct lod_object *lo,
        else
                lod_free_comp_entries(lo);
 
-       rc = lod_verify_striping(d, lo, buf, false);
+       rc = lod_verify_striping(env, d, lo, buf, false);
        if (rc)
                RETURN(-EINVAL);
 
@@ -2055,21 +2258,25 @@ int lod_qos_parse_config(const struct lu_env *env, struct lod_object *lo,
                }
 
                lod_comp->llc_pattern = v1->lmm_pattern;
-               lod_comp->llc_stripe_size = desc->ld_default_stripe_size;
-               if (v1->lmm_stripe_size)
-                       lod_comp->llc_stripe_size = v1->lmm_stripe_size;
+               lod_comp->llc_stripe_size = v1->lmm_stripe_size;
+               lod_adjust_stripe_size(lod_comp, desc->ld_default_stripe_size);
 
                lod_comp->llc_stripe_count = desc->ld_default_stripe_count;
                if (v1->lmm_stripe_count ||
                    lov_pattern(v1->lmm_pattern) == LOV_PATTERN_MDT)
                        lod_comp->llc_stripe_count = v1->lmm_stripe_count;
 
+               if (lov_pattern(lod_comp->llc_pattern) == LOV_PATTERN_MDT &&
+                   lod_comp->llc_stripe_count != 0) {
+                       CDEBUG(D_LAYOUT, "%s: invalid stripe count: %u\n",
+                              lod2obd(d)->obd_name,
+                              lod_comp->llc_stripe_count);
+                       GOTO(free_comp, rc = -EINVAL);
+               }
+
                lod_comp->llc_stripe_offset = v1->lmm_stripe_offset;
                lod_obj_set_pool(lo, i, pool_name);
 
-               LASSERT(ergo(lov_pattern(lod_comp->llc_pattern) ==
-                            LOV_PATTERN_MDT, lod_comp->llc_stripe_count == 0));
-
                if (pool_name == NULL)
                        continue;
 
@@ -2112,34 +2319,34 @@ free_comp:
 int lod_prepare_avoidance(const struct lu_env *env, struct lod_object *lo)
 {
        struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
-       struct lod_tgt_descs *ltds = &lod->lod_ost_descs;
        struct lod_avoid_guide *lag = &lod_env_info(env)->lti_avoid;
-       struct cfs_bitmap *bitmap = NULL;
+       unsigned long *bitmap = NULL;
        __u32 *new_oss = NULL;
 
-       lag->lag_ost_avail = ltds->ltd_tgtnr;
+       lag->lag_ost_avail = lod->lod_ost_count;
 
        /* reset OSS avoid guide array */
        lag->lag_oaa_count = 0;
-       if (lag->lag_oss_avoid_array && lag->lag_oaa_size < ltds->ltd_tgtnr) {
-               OBD_FREE(lag->lag_oss_avoid_array,
-                        sizeof(__u32) * lag->lag_oaa_size);
+       if (lag->lag_oss_avoid_array &&
+           lag->lag_oaa_size < lod->lod_ost_count) {
+               OBD_FREE_PTR_ARRAY(lag->lag_oss_avoid_array, lag->lag_oaa_size);
                lag->lag_oss_avoid_array = NULL;
                lag->lag_oaa_size = 0;
        }
 
        /* init OST avoid guide bitmap */
        if (lag->lag_ost_avoid_bitmap) {
-               if (ltds->ltd_tgtnr <= lag->lag_ost_avoid_bitmap->size) {
-                       CFS_RESET_BITMAP(lag->lag_ost_avoid_bitmap);
+               if (lod->lod_ost_count <= lag->lag_ost_avoid_size) {
+                       bitmap_zero(lag->lag_ost_avoid_bitmap,
+                                   lag->lag_ost_avoid_size);
                } else {
-                       CFS_FREE_BITMAP(lag->lag_ost_avoid_bitmap);
+                       bitmap_free(lag->lag_ost_avoid_bitmap);
                        lag->lag_ost_avoid_bitmap = NULL;
                }
        }
 
        if (!lag->lag_ost_avoid_bitmap) {
-               bitmap = CFS_ALLOCATE_BITMAP(ltds->ltd_tgtnr);
+               bitmap = bitmap_zalloc(lod->lod_ost_count, GFP_KERNEL);
                if (!bitmap)
                        return -ENOMEM;
        }
@@ -2151,19 +2358,21 @@ int lod_prepare_avoidance(const struct lu_env *env, struct lod_object *lo)
                 * using OST count to allocate the array to store the OSS
                 * id.
                 */
-               OBD_ALLOC(new_oss, sizeof(*new_oss) * ltds->ltd_tgtnr);
+               OBD_ALLOC_PTR_ARRAY(new_oss, lod->lod_ost_count);
                if (!new_oss) {
-                       CFS_FREE_BITMAP(bitmap);
+                       bitmap_free(bitmap);
                        return -ENOMEM;
                }
        }
 
        if (new_oss) {
                lag->lag_oss_avoid_array = new_oss;
-               lag->lag_oaa_size = ltds->ltd_tgtnr;
+               lag->lag_oaa_size = lod->lod_ost_count;
        }
-       if (bitmap)
+       if (bitmap) {
                lag->lag_ost_avoid_bitmap = bitmap;
+               lag->lag_ost_avoid_size = lod->lod_ost_count;
+       }
 
        return 0;
 }
@@ -2177,7 +2386,7 @@ void lod_collect_avoidance(struct lod_object *lo, struct lod_avoid_guide *lag,
 {
        struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct lod_layout_component *lod_comp = &lo->ldo_comp_entries[comp_idx];
-       struct cfs_bitmap *bitmap = lag->lag_ost_avoid_bitmap;
+       unsigned long *bitmap = lag->lag_ost_avoid_bitmap;
        int i, j;
 
        /* iterate mirrors */
@@ -2224,12 +2433,12 @@ void lod_collect_avoidance(struct lod_object *lo, struct lod_avoid_guide *lag,
                                ost = OST_TGT(lod, comp->llc_ost_indices[j]);
                                lsq = ost->ltd_qos.ltq_svr;
 
-                               if (cfs_bitmap_check(bitmap, ost->ltd_index))
+                               if (test_bit(ost->ltd_index, bitmap))
                                        continue;
 
                                QOS_DEBUG("OST%d used in conflicting mirror "
                                          "component\n", ost->ltd_index);
-                               cfs_bitmap_set(bitmap, ost->ltd_index);
+                               set_bit(ost->ltd_index, bitmap);
                                lag->lag_ost_avail--;
 
                                for (k = 0; k < lag->lag_oaa_count; k++) {
@@ -2267,7 +2476,7 @@ void lod_collect_avoidance(struct lod_object *lo, struct lod_avoid_guide *lag,
  */
 int lod_qos_prep_create(const struct lu_env *env, struct lod_object *lo,
                        struct lu_attr *attr, struct thandle *th,
-                       int comp_idx)
+                       int comp_idx, __u64 reserve)
 {
        struct lod_layout_component *lod_comp;
        struct lod_device      *d = lu2lod_dev(lod2lu_obj(lo)->lo_dev);
@@ -2301,8 +2510,8 @@ int lod_qos_prep_create(const struct lu_env *env, struct lod_object *lo,
                 * statfs and check OST targets now, since ld_active_tgt_count
                 * could be changed if some OSTs are [de]activated manually.
                 */
-               lod_qos_statfs_update(env, d);
-               stripe_len = lod_get_stripe_count(d, lo,
+               lod_qos_statfs_update(env, d, &d->lod_ost_descs);
+               stripe_len = lod_get_stripe_count(d, lo, comp_idx,
                                                  lod_comp->llc_stripe_count,
                                                  lod_comp->llc_pattern &
                                                  LOV_PATTERN_OVERSTRIPING);
@@ -2310,22 +2519,23 @@ int lod_qos_prep_create(const struct lu_env *env, struct lod_object *lo,
                if (stripe_len == 0)
                        GOTO(out, rc = -ERANGE);
                lod_comp->llc_stripe_count = stripe_len;
-               OBD_ALLOC(stripe, sizeof(stripe[0]) * stripe_len);
+               OBD_ALLOC_PTR_ARRAY(stripe, stripe_len);
                if (stripe == NULL)
                        GOTO(out, rc = -ENOMEM);
-               OBD_ALLOC(ost_indices, sizeof(*ost_indices) * stripe_len);
+               OBD_ALLOC_PTR_ARRAY(ost_indices, stripe_len);
                if (!ost_indices)
                        GOTO(out, rc = -ENOMEM);
 
+repeat:
                lod_getref(&d->lod_ost_descs);
                /* XXX: support for non-0 files w/o objects */
                CDEBUG(D_OTHER, "tgt_count %d stripe_count %d\n",
-                               d->lod_desc.ld_tgt_count, stripe_len);
+                      d->lod_ost_count, stripe_len);
 
                if (lod_comp->llc_ostlist.op_array &&
                    lod_comp->llc_ostlist.op_count) {
                        rc = lod_alloc_ost_list(env, lo, stripe, ost_indices,
-                                               th, comp_idx);
+                                               th, comp_idx, reserve);
                } else if (lod_comp->llc_stripe_offset == LOV_OFFSET_DEFAULT) {
                        /**
                         * collect OSTs and OSSs used in other mirrors whose
@@ -2339,14 +2549,16 @@ int lod_qos_prep_create(const struct lu_env *env, struct lod_object *lo,
                                  comp_idx);
                        lod_collect_avoidance(lo, lag, comp_idx);
 
-                       rc = lod_alloc_qos(env, lo, stripe, ost_indices, flag,
-                                          th, comp_idx);
+                       rc = lod_ost_alloc_qos(env, lo, stripe, ost_indices,
+                                              flag, th, comp_idx, reserve);
                        if (rc == -EAGAIN)
-                               rc = lod_alloc_rr(env, lo, stripe, ost_indices,
-                                                 flag, th, comp_idx);
+                               rc = lod_ost_alloc_rr(env, lo, stripe,
+                                                     ost_indices, flag, th,
+                                                     comp_idx, reserve);
                } else {
-                       rc = lod_alloc_specific(env, lo, stripe, ost_indices,
-                                               flag, th, comp_idx);
+                       rc = lod_ost_alloc_specific(env, lo, stripe,
+                                                   ost_indices, flag, th,
+                                                   comp_idx, reserve);
                }
 put_ldts:
                lod_putref(d, &d->lod_ost_descs);
@@ -2354,6 +2566,15 @@ put_ldts:
                        for (i = 0; i < stripe_len; i++)
                                if (stripe[i] != NULL)
                                        dt_object_put(env, stripe[i]);
+
+                       /* In case there is no space on any OST, let's ignore
+                        * the @reserve space to avoid an error at the init
+                        * time, probably the actual IO will be less than the
+                        * given @reserve space (aka extension_size). */
+                       if (reserve) {
+                               reserve = 0;
+                               goto repeat;
+                       }
                        lod_comp->llc_stripe_count = 0;
                } else {
                        lod_comp->llc_stripe = stripe;
@@ -2390,10 +2611,9 @@ put_ldts:
 out:
        if (rc < 0) {
                if (stripe)
-                       OBD_FREE(stripe, sizeof(stripe[0]) * stripe_len);
+                       OBD_FREE_PTR_ARRAY(stripe, stripe_len);
                if (ost_indices)
-                       OBD_FREE(ost_indices,
-                                sizeof(*ost_indices) * stripe_len);
+                       OBD_FREE_PTR_ARRAY(ost_indices, stripe_len);
        }
        RETURN(rc);
 }
@@ -2414,7 +2634,7 @@ int lod_prepare_create(const struct lu_env *env, struct lod_object *lo,
        /* no OST available */
        /* XXX: should we be waiting a bit to prevent failures during
         * cluster initialization? */
-       if (d->lod_ostnr == 0)
+       if (!d->lod_ost_count)
                RETURN(-EIO);
 
        /*
@@ -2445,7 +2665,7 @@ int lod_prepare_create(const struct lu_env *env, struct lod_object *lo,
                extent = &lod_comp->llc_extent;
                QOS_DEBUG("comp[%d] %lld "DEXT"\n", i, size, PEXT(extent));
                if (!lo->ldo_is_composite || size >= extent->e_start) {
-                       rc = lod_qos_prep_create(env, lo, attr, th, i);
+                       rc = lod_qos_prep_create(env, lo, attr, th, i, 0);
                        if (rc)
                                break;
                }