lustre/lov/lov_qos.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2002, 2003 Cluster File Systems, Inc.
   5  *
   6  *   This file is part of the Lustre file system, http://www.lustre.org
   7  *   Lustre is a trademark of Cluster File Systems, Inc.
   8  *
   9  *   You may have signed or agreed to another license before downloading
  10  *   this software.  If so, you are bound by the terms and conditions
  11  *   of that agreement, and the following does not apply to you.  See the
  12  *   LICENSE file included with this distribution for more information.
  13  *
  14  *   If you did not agree to a different license, then this copy of Lustre
  15  *   is open source software; you can redistribute it and/or modify it
  16  *   under the terms of version 2 of the GNU General Public License as
  17  *   published by the Free Software Foundation.
  18  *
  19  *   In either case, Lustre is distributed in the hope that it will be
  20  *   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  21  *   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *   license text for more details.
  23  */
  24
  25 #ifndef EXPORT_SYMTAB
  26 # define EXPORT_SYMTAB
  27 #endif
  28 #define DEBUG_SUBSYSTEM S_LOV
  29
  30 #ifdef __KERNEL__
  31 #include <libcfs/libcfs.h>
  32 #else
  33 #include <liblustre.h>
  34 #endif
  35
  36 #include <obd_class.h>
  37 #include <obd_lov.h>
  38 #include "lov_internal.h"
  39
  40
  41 /* #define QOS_DEBUG 1 */
  42 #define D_QOS D_OTHER
  43
  44 #define TGT_BAVAIL(i)  (lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_bavail * \
  45                         lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_bsize)
  46 #define TGT_FFREE(i)   (lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_ffree)
  47
  48
  49 int qos_add_tgt(struct obd_device *obd, __u32 index)
  50 {
  51         struct lov_obd *lov = &obd->u.lov;
  52         struct lov_qos_oss *oss, *temposs;
  53         struct obd_export *exp = lov->lov_tgts[index]->ltd_exp;
  54         int rc = 0, found = 0;
  55         ENTRY;
  56
  57         /* We only need this QOS struct on MDT, not clients - but we may not
  58            have registered the lov's observer yet, so there's no way to check
  59            here. */
  60
  61         if (!exp || !exp->exp_connection) {
  62                 CERROR("Missing connection\n");
  63                 RETURN(-ENOTCONN);
  64         }
  65
  66         down_write(&lov->lov_qos.lq_rw_sem);
  67         mutex_down(&lov->lov_lock);
  68         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
  69                 if (obd_uuid_equals(&oss->lqo_uuid,
  70                                     &exp->exp_connection->c_remote_uuid)) {
  71                         found++;
  72                         break;
  73                 }
  74         }
  75
  76         if (!found) {
  77                 OBD_ALLOC_PTR(oss);
  78                 if (!oss)
  79                         GOTO(out, rc = -ENOMEM);
  80                 memcpy(&oss->lqo_uuid,
  81                        &exp->exp_connection->c_remote_uuid,
  82                        sizeof(oss->lqo_uuid));
  83         } else {
  84                 /* Assume we have to move this one */
  85                 list_del(&oss->lqo_oss_list);
  86         }
  87
  88         oss->lqo_ost_count++;
  89         lov->lov_tgts[index]->ltd_qos.ltq_oss = oss;
  90
  91         /* Add sorted by # of OSTs.  Find the first entry that we're
  92            bigger than... */
  93         list_for_each_entry(temposs, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
  94                 if (oss->lqo_ost_count > temposs->lqo_ost_count)
  95                         break;
  96         }
  97         /* ...and add before it.  If we're the first or smallest, temposs
  98            points to the list head, and we add to the end. */
  99         list_add_tail(&oss->lqo_oss_list, &temposs->lqo_oss_list);
 100
 101         lov->lov_qos.lq_dirty = 1;
 102         lov->lov_qos.lq_dirty_rr = 1;
 103
 104         CDEBUG(D_QOS, "add tgt %s to OSS %s (#%d)\n",
 105                obd_uuid2str(&lov->lov_tgts[index]->ltd_uuid),
 106                obd_uuid2str(&oss->lqo_uuid),
 107                oss->lqo_ost_count);
 108
 109 out:
 110         mutex_up(&lov->lov_lock);
 111         up_write(&lov->lov_qos.lq_rw_sem);
 112         RETURN(rc);
 113 }
 114
 115 int qos_del_tgt(struct obd_device *obd, __u32 index)
 116 {
 117         struct lov_obd *lov = &obd->u.lov;
 118         struct lov_qos_oss *oss;
 119         int rc = 0;
 120         ENTRY;
 121
 122         down_write(&lov->lov_qos.lq_rw_sem);
 123
 124         oss = lov->lov_tgts[index]->ltd_qos.ltq_oss;
 125         if (!oss)
 126                 GOTO(out, rc = -ENOENT);
 127
 128         oss->lqo_ost_count--;
 129         if (oss->lqo_ost_count == 0) {
 130                 CDEBUG(D_QOS, "removing OSS %s\n",
 131                        obd_uuid2str(&oss->lqo_uuid));
 132                 list_del(&oss->lqo_oss_list);
 133                 OBD_FREE_PTR(oss);
 134         }
 135
 136         lov->lov_qos.lq_dirty = 1;
 137         lov->lov_qos.lq_dirty_rr = 1;
 138 out:
 139         up_write(&lov->lov_qos.lq_rw_sem);
 140         RETURN(rc);
 141 }
 142
 143 /* Recalculate per-object penalties for OSSs and OSTs,
 144    depends on size of each ost in an oss */
 145 static int qos_calc_ppo(struct obd_device *obd)
 146 {
 147         struct lov_obd *lov = &obd->u.lov;
 148         struct lov_qos_oss *oss;
 149         __u64 ba_max, ba_min, temp;
 150         __u32 num_active;
 151         int rc, i, prio_wide;
 152         ENTRY;
 153
 154         if (!lov->lov_qos.lq_dirty)
 155                 GOTO(out, rc = 0);
 156
 157         num_active = lov->desc.ld_active_tgt_count - 1;
 158         if (num_active < 1)
 159                 GOTO(out, rc = -EAGAIN);
 160
 161         /* find bavail on each OSS */
 162         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 163                 oss->lqo_bavail = 0;
 164         }
 165         lov->lov_qos.lq_active_oss_count = 0;
 166
 167         /* How badly user wants to select osts "widely" (not recently chosen
 168            and not on recent oss's).  As opposed to "freely" (free space
 169            avail.) 0-256. */
 170         prio_wide = 256 - lov->lov_qos.lq_prio_free;
 171
 172         ba_min = (__u64)(-1);
 173         ba_max = 0;
 174         /* Calculate OST penalty per object */
 175         /* (lov ref taken in alloc_qos) */
 176         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 177                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 178                         continue;
 179                 temp = TGT_BAVAIL(i);
 180                 if (!temp)
 181                         continue;
 182                 ba_min = min(temp, ba_min);
 183                 ba_max = max(temp, ba_max);
 184
 185                 /* Count the number of usable OSS's */
 186                 if (lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_bavail == 0)
 187                         lov->lov_qos.lq_active_oss_count++;
 188                 lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_bavail += temp;
 189
 190                 /* per-OST penalty is prio * TGT_bavail / (num_ost - 1) / 2 */
 191                 temp >>= 1;
 192                 do_div(temp, num_active);
 193                 lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj =
 194                         (temp * prio_wide) >> 8;
 195
 196                 if (lov->lov_qos.lq_reset == 0)
 197                         lov->lov_tgts[i]->ltd_qos.ltq_penalty = 0;
 198         }
 199
 200         num_active = lov->lov_qos.lq_active_oss_count - 1;
 201         if (num_active < 1) {
 202                 /* If there's only 1 OSS, we can't penalize it, so instead
 203                    we have to double the OST penalty */
 204                 num_active = 1;
 205                 for (i = 0; i < lov->desc.ld_tgt_count; i++)
 206                         lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj <<= 1;
 207         }
 208
 209         /* Per-OSS penalty is prio * oss_avail / oss_osts / (num_oss - 1) / 2 */
 210         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 211                 temp = oss->lqo_bavail >> 1;
 212                 do_div(temp, oss->lqo_ost_count * num_active);
 213                 oss->lqo_penalty_per_obj = (temp * prio_wide) >> 8;
 214                 if (lov->lov_qos.lq_reset == 0)
 215                         oss->lqo_penalty = 0;
 216         }
 217
 218         lov->lov_qos.lq_dirty = 0;
 219         lov->lov_qos.lq_reset = 0;
 220
 221         /* If each ost has almost same free space,
 222          * do rr allocation for better creation performance */
 223         lov->lov_qos.lq_same_space = 0;
 224         temp = ba_max - ba_min;
 225         ba_min = (ba_min * 51) >> 8;     /* 51/256 = .20 */
 226         if (temp < ba_min) {
 227                 /* Difference is less than 20% */
 228                 lov->lov_qos.lq_same_space = 1;
 229                 /* Reset weights for the next time we enter qos mode */
 230                 lov->lov_qos.lq_reset = 0;
 231         }
 232         rc = 0;
 233
 234 out:
 235         if (!rc && lov->lov_qos.lq_same_space)
 236                 RETURN(-EAGAIN);
 237         RETURN(rc);
 238 }
 239
 240 static int qos_calc_weight(struct lov_obd *lov, int i)
 241 {
 242         __u64 temp, temp2;
 243
 244         /* Final ost weight = TGT_BAVAIL - ost_penalty - oss_penalty */
 245         temp = TGT_BAVAIL(i);
 246         temp2 = lov->lov_tgts[i]->ltd_qos.ltq_penalty +
 247                 lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty;
 248         if (temp < temp2)
 249                 lov->lov_tgts[i]->ltd_qos.ltq_weight = 0;
 250         else
 251                 lov->lov_tgts[i]->ltd_qos.ltq_weight = temp - temp2;
 252         return 0;
 253 }
 254
 255 /* We just used this index for a stripe; adjust everyone's weights */
 256 static int qos_used(struct lov_obd *lov, __u32 index, __u64 *total_wt)
 257 {
 258         struct lov_qos_oss *oss;
 259         int i;
 260         ENTRY;
 261
 262         /* Don't allocate from this stripe anymore, until the next alloc_qos */
 263         lov->lov_tgts[index]->ltd_qos.ltq_usable = 0;
 264
 265         oss = lov->lov_tgts[index]->ltd_qos.ltq_oss;
 266
 267         /* Decay old penalty by half (we're adding max penalty, and don't
 268            want it to run away.) */
 269         lov->lov_tgts[index]->ltd_qos.ltq_penalty >>= 1;
 270         oss->lqo_penalty >>= 1;
 271
 272         /* Set max penalties for this OST and OSS */
 273         lov->lov_tgts[index]->ltd_qos.ltq_penalty +=
 274                 lov->lov_tgts[index]->ltd_qos.ltq_penalty_per_obj *
 275                 lov->desc.ld_active_tgt_count;
 276         oss->lqo_penalty += oss->lqo_penalty_per_obj *
 277                 lov->lov_qos.lq_active_oss_count;
 278
 279         /* Decrease all OSS penalties */
 280         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 281                 if (oss->lqo_penalty < oss->lqo_penalty_per_obj)
 282                         oss->lqo_penalty = 0;
 283                 else
 284                         oss->lqo_penalty -= oss->lqo_penalty_per_obj;
 285         }
 286
 287         *total_wt = 0;
 288         /* Decrease all OST penalties */
 289         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 290                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 291                         continue;
 292                 if (lov->lov_tgts[i]->ltd_qos.ltq_penalty <
 293                     lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj)
 294                         lov->lov_tgts[i]->ltd_qos.ltq_penalty = 0;
 295                 else
 296                         lov->lov_tgts[i]->ltd_qos.ltq_penalty -=
 297                         lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj;
 298
 299                 qos_calc_weight(lov, i);
 300
 301                 /* Recalc the total weight of usable osts */
 302                 if (lov->lov_tgts[i]->ltd_qos.ltq_usable)
 303                         *total_wt += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 304
 305 #ifdef QOS_DEBUG
 306                 CDEBUG(D_QOS, "recalc tgt %d avail="LPU64
 307                        " ostppo="LPU64" ostp="LPU64" ossppo="LPU64
 308                        " ossp="LPU64" wt="LPU64"\n",
 309                        i, TGT_BAVAIL(i),
 310                        lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj,
 311                        lov->lov_tgts[i]->ltd_qos.ltq_penalty,
 312                        lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty_per_obj,
 313                        lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty,
 314                        lov->lov_tgts[i]->ltd_qos.ltq_weight);
 315 #endif
 316         }
 317
 318         RETURN(0);
 319 }
 320
 321 #define LOV_QOS_EMPTY ((__u32)-1)
 322 /* compute optimal round-robin order, based on OSTs per OSS */
 323 static int qos_calc_rr(struct lov_obd *lov)
 324 {
 325         struct lov_qos_oss *oss;
 326         unsigned ost_count, placed;
 327         int i;
 328         ENTRY;
 329
 330         if (!lov->lov_qos.lq_dirty_rr) {
 331                 LASSERT(lov->lov_qos.lq_rr_size);
 332                 RETURN(0);
 333         }
 334
 335         down_write(&lov->lov_qos.lq_rw_sem);
 336         ost_count = lov->desc.ld_tgt_count;
 337
 338         if (lov->lov_qos.lq_rr_size)
 339                 OBD_FREE(lov->lov_qos.lq_rr_array, lov->lov_qos.lq_rr_size);
 340         lov->lov_qos.lq_rr_size = ost_count *
 341                 sizeof(lov->lov_qos.lq_rr_array[0]);
 342         OBD_ALLOC(lov->lov_qos.lq_rr_array, lov->lov_qos.lq_rr_size);
 343         if (!lov->lov_qos.lq_rr_array) {
 344                 lov->lov_qos.lq_rr_size = 0;
 345                 up_write(&lov->lov_qos.lq_rw_sem);
 346                 RETURN(-ENOMEM);
 347         }
 348
 349         for (i = 0; i < ost_count; i++)
 350                 lov->lov_qos.lq_rr_array[i] = LOV_QOS_EMPTY;
 351
 352         /* Place all the OSTs from 1 OSS at the same time. */
 353         placed = 0;
 354         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
 355                 int j = 0;
 356                 for (i = 0; i < ost_count; i++) {
 357                       LASSERT(lov->lov_tgts[i] != NULL);
 358                       if (lov->lov_tgts[i]->ltd_qos.ltq_oss == oss) {
 359                               /* Evenly space these OSTs across arrayspace */
 360                               int next = j * ost_count / oss->lqo_ost_count;
 361                               while (lov->lov_qos.lq_rr_array[next] !=
 362                                      LOV_QOS_EMPTY)
 363                                       next = (next + 1) % ost_count;
 364                               lov->lov_qos.lq_rr_array[next] = i;
 365                               j++;
 366                               placed++;
 367                       }
 368                 }
 369                 LASSERT(j == oss->lqo_ost_count);
 370         }
 371
 372         lov->lov_qos.lq_dirty_rr = 0;
 373         up_write(&lov->lov_qos.lq_rw_sem);
 374
 375 #ifdef QOS_DEBUG
 376         for (i = 0; i < ost_count; i++) {
 377                 LCONSOLE(D_QOS, "rr %d ost %d\n", i,
 378                          lov->lov_qos.lq_rr_array[i]);
 379         }
 380 #endif
 381
 382         if (placed != ost_count) {
 383                 /* This should never happen */
 384                 CERROR("Placed %d of %d osts\n", placed, ost_count);
 385                 for (i = 0; i < ost_count; i++) {
 386                         LCONSOLE(D_WARNING, "rr %d ost %d\n", i,
 387                                  lov->lov_qos.lq_rr_array[i]);
 388                 }
 389                 LBUG();
 390         }
 391
 392         RETURN(0);
 393 }
 394
 395
 396 void qos_shrink_lsm(struct lov_request_set *set)
 397 {
 398         struct lov_stripe_md *lsm = set->set_oi->oi_md, *lsm_new;
 399         /* XXX LOV STACKING call into osc for sizes */
 400         unsigned oldsize, newsize;
 401
 402         if (set->set_oti && set->set_cookies && set->set_cookie_sent) {
 403                 struct llog_cookie *cookies;
 404                 oldsize = lsm->lsm_stripe_count * sizeof(*cookies);
 405                 newsize = set->set_count * sizeof(*cookies);
 406
 407                 cookies = set->set_cookies;
 408                 oti_alloc_cookies(set->set_oti, set->set_count);
 409                 if (set->set_oti->oti_logcookies) {
 410                         memcpy(set->set_oti->oti_logcookies, cookies, newsize);
 411                         OBD_FREE(cookies, oldsize);
 412                         set->set_cookies = set->set_oti->oti_logcookies;
 413                 } else {
 414                         CWARN("'leaking' %d bytes\n", oldsize - newsize);
 415                 }
 416         }
 417
 418         CWARN("using fewer stripes for object "LPX64": old %u new %u\n",
 419               lsm->lsm_object_id, lsm->lsm_stripe_count, set->set_count);
 420
 421         oldsize = lov_stripe_md_size(lsm->lsm_stripe_count);
 422         newsize = lov_stripe_md_size(set->set_count);
 423         OBD_ALLOC(lsm_new, newsize);
 424         if (lsm_new != NULL) {
 425                 memcpy(lsm_new, lsm, newsize);
 426                 lsm_new->lsm_stripe_count = set->set_count;
 427                 OBD_FREE(lsm, oldsize);
 428                 set->set_oi->oi_md = lsm_new;
 429         } else {
 430                 CWARN("'leaking' %d bytes\n", oldsize - newsize);
 431         }
 432 }
 433
 434 int qos_remedy_create(struct lov_request_set *set, struct lov_request *req)
 435 {
 436         struct lov_stripe_md *lsm = set->set_oi->oi_md;
 437         struct lov_obd *lov = &set->set_exp->exp_obd->u.lov;
 438         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
 439         int stripe, i, rc = -EIO;
 440         ENTRY;
 441
 442         ost_idx = (req->rq_idx + lsm->lsm_stripe_count) % ost_count;
 443         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
 444                 if (!lov->lov_tgts[ost_idx] ||
 445                     !lov->lov_tgts[ost_idx]->ltd_active)
 446                         continue;
 447                 /* check if objects has been created on this ost */
 448                 for (stripe = 0; stripe < lsm->lsm_stripe_count; stripe++) {
 449                         if (stripe == req->rq_stripe)
 450                                 continue;
 451                         if (ost_idx == lsm->lsm_oinfo[stripe].loi_ost_idx)
 452                                 break;
 453                 }
 454
 455                 if (stripe >= lsm->lsm_stripe_count) {
 456                         req->rq_idx = ost_idx;
 457                         rc = obd_create(lov->lov_tgts[ost_idx]->ltd_exp,
 458                                         req->rq_oi.oi_oa, &req->rq_oi.oi_md,
 459                                         set->set_oti);
 460                         if (!rc)
 461                                 break;
 462                 }
 463         }
 464         RETURN(rc);
 465 }
 466
 467 #define LOV_CREATE_RESEED_MULT 4
 468 #define LOV_CREATE_RESEED_MIN  1000
 469 /* Allocate objects on osts with round-robin algorithm */
 470 static int alloc_rr(struct lov_obd *lov, int *idx_arr, int *stripe_cnt)
 471 {
 472         unsigned array_idx, ost_count = lov->desc.ld_tgt_count;
 473         unsigned ost_active_count = lov->desc.ld_active_tgt_count;
 474         int i, *idx_pos = idx_arr;
 475         __u32 ost_idx;
 476         ENTRY;
 477
 478         i = qos_calc_rr(lov);
 479         if (i)
 480                 RETURN(i);
 481
 482         if (--lov->lov_start_count <= 0) {
 483                 lov->lov_start_idx = ll_rand() % ost_count;
 484                 lov->lov_start_count =
 485                         (LOV_CREATE_RESEED_MIN / max(ost_active_count, 1U) +
 486                          LOV_CREATE_RESEED_MULT) * max(ost_active_count, 1U);
 487         } else if (*stripe_cnt >= ost_active_count ||
 488                    lov->lov_start_idx > ost_count) {
 489                 /* If we have allocated from all of the OSTs, slowly
 490                    precess the next start */
 491                 lov->lov_start_idx %= ost_count;
 492                 ++lov->lov_offset_idx;
 493         }
 494         array_idx = (lov->lov_start_idx + lov->lov_offset_idx) % ost_count;
 495 #ifdef QOS_DEBUG
 496         CDEBUG(D_QOS, "want %d startidx %d startcnt %d offset %d arrayidx %d\n",
 497                *stripe_cnt, lov->lov_start_idx, lov->lov_start_count,
 498                lov->lov_offset_idx, array_idx);
 499 #endif
 500
 501         down_read(&lov->lov_qos.lq_rw_sem);
 502         for (i = 0; i < ost_count; i++, array_idx=(array_idx + 1) % ost_count) {
 503                 ++lov->lov_start_idx;
 504                 ost_idx = lov->lov_qos.lq_rr_array[array_idx];
 505 #ifdef QOS_DEBUG
 506                 CDEBUG(D_QOS, "#%d strt %d act %d strp %d ary %d idx %d\n",
 507                        i, lov->lov_start_idx,
 508                        lov->lov_tgts[ost_idx] ?
 509                        lov->lov_tgts[ost_idx].ltd_active : 0,
 510                        idx_pos - idx_arr, array_idx, ost_idx);
 511 #endif
 512                 if (!lov->lov_tgts[ost_idx] ||
 513                     !lov->lov_tgts[ost_idx]->ltd_active)
 514                         continue;
 515                 *idx_pos = ost_idx;
 516                 idx_pos++;
 517                 /* We have enough stripes */
 518                 if (idx_pos - idx_arr == *stripe_cnt)
 519                         break;
 520         }
 521         up_read(&lov->lov_qos.lq_rw_sem);
 522
 523         *stripe_cnt = idx_pos - idx_arr;
 524         RETURN(0);
 525 }
 526
 527 /* alloc objects on osts with specific stripe offset */
 528 static int alloc_specific(struct lov_obd *lov, struct lov_stripe_md *lsm,
 529                           int *idx_arr)
 530 {
 531         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
 532         int i, *idx_pos = idx_arr;
 533         ENTRY;
 534
 535         ost_idx = lsm->lsm_oinfo[0].loi_ost_idx;
 536         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
 537                 if (!lov->lov_tgts[ost_idx] ||
 538                     !lov->lov_tgts[ost_idx]->ltd_active) {
 539                         continue;
 540                 }
 541                 *idx_pos = ost_idx;
 542                 idx_pos++;
 543                 /* got enough ost */
 544                 if (idx_pos - idx_arr == lsm->lsm_stripe_count)
 545                         RETURN(0);
 546         }
 547         /* If we were passed specific striping params, then a failure to
 548          * meet those requirements is an error, since we can't reallocate
 549          * that memory (it might be part of a larger array or something).
 550          *
 551          * We can only get here if lsm_stripe_count was originally > 1.
 552          */
 553         CERROR("can't lstripe objid "LPX64": have %u want %u\n",
 554                lsm->lsm_object_id, idx_pos - idx_arr, lsm->lsm_stripe_count);
 555         RETURN(-EFBIG);
 556 }
 557
 558 /* Alloc objects on osts with optimization based on:
 559    - free space
 560    - network resources (shared OSS's)
 561 */
 562 static int alloc_qos(struct obd_export *exp, int *idx_arr, int *stripe_cnt)
 563 {
 564         struct lov_obd *lov = &exp->exp_obd->u.lov;
 565         static time_t last_warn = 0;
 566         time_t now = cfs_time_current_sec();
 567         __u64 cur_weight, temp, rand, bavail, total_bavail, total_weight = 0;
 568         __u32 ost_count;
 569         int nfound, good_osts, i, warn = 0, rc = 0;
 570         ENTRY;
 571
 572         lov_getref(exp->exp_obd);
 573         down_write(&lov->lov_qos.lq_rw_sem);
 574
 575         ost_count = lov->desc.ld_tgt_count;
 576
 577         if (lov->desc.ld_active_tgt_count < 2)
 578                 GOTO(out, rc = -EAGAIN);
 579
 580         rc = qos_calc_ppo(exp->exp_obd);
 581         if (rc)
 582                 GOTO(out, rc);
 583
 584         total_bavail = 0;
 585         good_osts = 0;
 586         /* Warn users about zero available space/inode every 30 min */
 587         if (cfs_time_sub(now, last_warn) > 60 * 30)
 588                 warn = 1;
 589         /* Find all the OSTs that are valid stripe candidates */
 590         for (i = 0; i < ost_count; i++) {
 591                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
 592                         continue;
 593                 bavail = TGT_BAVAIL(i);
 594                 if (!bavail) {
 595                         if (warn) {
 596                                 CDEBUG(D_QOS, "no free space on %s\n",
 597                                        obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
 598                                 last_warn = now;
 599                         }
 600                         continue;
 601                 }
 602                 if (!TGT_FFREE(i)) {
 603                         if (warn) {
 604                                 CDEBUG(D_QOS, "no free inodes on %s\n",
 605                                        obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
 606                                 last_warn = now;
 607                         }
 608                         continue;
 609                 }
 610
 611                 lov->lov_tgts[i]->ltd_qos.ltq_usable = 1;
 612                 qos_calc_weight(lov, i);
 613                 total_bavail += bavail;
 614                 total_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 615
 616                 good_osts++;
 617         }
 618
 619         if (!total_bavail)
 620                 GOTO(out, rc = -ENOSPC);
 621
 622         /* if we don't have enough good OSTs, we reduce the stripe count. */
 623         if (good_osts < *stripe_cnt)
 624                 *stripe_cnt = good_osts;
 625
 626         if (!*stripe_cnt)
 627                 GOTO(out, rc = -EAGAIN);
 628
 629         /* Find enough OSTs with weighted random allocation. */
 630         nfound = 0;
 631         while (nfound < *stripe_cnt) {
 632                 cur_weight = 0;
 633                 rc = -ENODEV;
 634
 635                 if (total_weight) {
 636                         /* If total_weight > 32-bit, make a 64-bit random # */
 637                         temp = (total_weight & 0xffffffff00000000ULL ?
 638                                 (__u64)ll_rand() << 32 : 0ULL) | ll_rand();
 639                         /* Random number between 0 and total_weight */
 640                         rand = do_div(temp, total_weight);
 641                 } else {
 642                         rand = 0;
 643                 }
 644
 645                 /* On average, this will hit larger-weighted osts more often.
 646                    0-weight osts will always get used last (only when rand=0).*/
 647                 for (i = 0; i < ost_count; i++) {
 648                         if (!lov->lov_tgts[i]->ltd_qos.ltq_usable)
 649                                 continue;
 650                         cur_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
 651                         if (cur_weight >= rand) {
 652 #ifdef QOS_DEBUG
 653                                 CDEBUG(D_QOS, "assigned stripe=%d to idx=%d\n",
 654                                        nfound, i);
 655 #endif
 656                                 idx_arr[nfound++] = i;
 657                                 qos_used(lov, i, &total_weight);
 658                                 rc = 0;
 659                                 break;
 660                         }
 661                 }
 662                 /* should never satisfy below condition */
 663                 if (rc) {
 664                         CERROR("Didn't find any OSTs?\n");
 665                         break;
 666                 }
 667         }
 668         LASSERT(nfound == *stripe_cnt);
 669
 670 out:
 671         up_write(&lov->lov_qos.lq_rw_sem);
 672
 673         if (rc == -EAGAIN)
 674                 rc = alloc_rr(lov, idx_arr, stripe_cnt);
 675
 676         lov_putref(exp->exp_obd);
 677         RETURN(rc);
 678 }
 679
 680 /* return new alloced stripe count on success */
 681 static int alloc_idx_array(struct obd_export *exp, struct lov_stripe_md *lsm,
 682                            int newea, int **idx_arr, int *arr_cnt)
 683 {
 684         struct lov_obd *lov = &exp->exp_obd->u.lov;
 685         int stripe_cnt = lsm->lsm_stripe_count;
 686         int i, rc = 0;
 687         int *tmp_arr = NULL;
 688         ENTRY;
 689
 690         *arr_cnt = stripe_cnt;
 691         OBD_ALLOC(tmp_arr, *arr_cnt * sizeof(int));
 692         if (tmp_arr == NULL)
 693                 RETURN(-ENOMEM);
 694         for (i = 0; i < *arr_cnt; i++)
 695                 tmp_arr[i] = -1;
 696
 697         if (newea ||
 698             lsm->lsm_oinfo[0].loi_ost_idx >= lov->desc.ld_tgt_count)
 699                 rc = alloc_qos(exp, tmp_arr, &stripe_cnt);
 700         else
 701                 rc = alloc_specific(lov, lsm, tmp_arr);
 702
 703         if (rc)
 704                 GOTO(out_arr, rc);
 705
 706         *idx_arr = tmp_arr;
 707         RETURN(stripe_cnt);
 708 out_arr:
 709         OBD_FREE(tmp_arr, *arr_cnt * sizeof(int));
 710         *arr_cnt = 0;
 711         RETURN(rc);
 712 }
 713
 714 static void free_idx_array(int *idx_arr, int arr_cnt)
 715 {
 716         if (arr_cnt)
 717                 OBD_FREE(idx_arr, arr_cnt * sizeof(int));
 718 }
 719
 720 int qos_prep_create(struct obd_export *exp, struct lov_request_set *set)
 721 {
 722         struct lov_obd *lov = &exp->exp_obd->u.lov;
 723         struct lov_stripe_md *lsm;
 724         struct obdo *src_oa = set->set_oi->oi_oa;
 725         struct obd_trans_info *oti = set->set_oti;
 726         int i, stripes, rc = 0, newea = 0;
 727         int *idx_arr, idx_cnt = 0;
 728         ENTRY;
 729
 730         LASSERT(src_oa->o_valid & OBD_MD_FLID);
 731         LASSERT(src_oa->o_valid & OBD_MD_FLGROUP);
 732
 733         if (set->set_oi->oi_md == NULL) {
 734                 int stripe_cnt = lov_get_stripecnt(lov, 0);
 735
 736                 /* If the MDS file was truncated up to some size, stripe over
 737                  * enough OSTs to allow the file to be created at that size.
 738                  * This may mean we use more than the default # of stripes. */
 739                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
 740                         obd_size min_bavail = (obd_size)-1;
 741
 742                         /* Find a small number of stripes we can use
 743                            (up to # of active osts). */
 744                         stripes = 1;
 745                         lov_getref(exp->exp_obd);
 746                         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
 747                                 if (!lov->lov_tgts[i] ||
 748                                     !lov->lov_tgts[i]->ltd_active)
 749                                         continue;
 750                                 min_bavail = min(min_bavail, TGT_BAVAIL(i));
 751                                 if (min_bavail * stripes > src_oa->o_size)
 752                                         break;
 753                                 stripes++;
 754                         }
 755                         lov_putref(exp->exp_obd);
 756
 757                         if (stripes < stripe_cnt)
 758                                 stripes = stripe_cnt;
 759                 } else {
 760                         stripes = stripe_cnt;
 761                 }
 762
 763                 rc = lov_alloc_memmd(&set->set_oi->oi_md, stripes,
 764                                      lov->desc.ld_pattern ?
 765                                      lov->desc.ld_pattern : LOV_PATTERN_RAID0,
 766                                      LOV_MAGIC);
 767                 if (rc < 0)
 768                         GOTO(out_err, rc);
 769                 rc = 0;
 770                 newea = 1;
 771         }
 772
 773         lsm = set->set_oi->oi_md;
 774         lsm->lsm_object_id = src_oa->o_id;
 775         lsm->lsm_object_gr = src_oa->o_gr;
 776
 777         if (!lsm->lsm_stripe_size)
 778                 lsm->lsm_stripe_size = lov->desc.ld_default_stripe_size;
 779         if (!lsm->lsm_pattern) {
 780                 LASSERT(lov->desc.ld_pattern);
 781                 lsm->lsm_pattern = lov->desc.ld_pattern;
 782         }
 783
 784         stripes = alloc_idx_array(exp, lsm, newea, &idx_arr, &idx_cnt);
 785         LASSERT(stripes <= lsm->lsm_stripe_count);
 786         if (stripes <= 0)
 787                 GOTO(out_err, rc = stripes ? stripes : -EIO);
 788
 789         for (i = 0; i < stripes; i++) {
 790                 struct lov_request *req;
 791                 int ost_idx = idx_arr[i];
 792                 LASSERT(ost_idx >= 0);
 793
 794                 OBD_ALLOC(req, sizeof(*req));
 795                 if (req == NULL)
 796                         GOTO(out_err, rc = -ENOMEM);
 797                 lov_set_add_req(req, set);
 798
 799                 req->rq_buflen = sizeof(*req->rq_oi.oi_md);
 800                 OBD_ALLOC(req->rq_oi.oi_md, req->rq_buflen);
 801                 if (req->rq_oi.oi_md == NULL)
 802                         GOTO(out_err, rc = -ENOMEM);
 803
 804                 req->rq_oi.oi_oa = obdo_alloc();
 805                 if (req->rq_oi.oi_oa == NULL)
 806                         GOTO(out_err, rc = -ENOMEM);
 807
 808                 req->rq_idx = ost_idx;
 809                 req->rq_stripe = i;
 810                 /* create data objects with "parent" OA */
 811                 memcpy(req->rq_oi.oi_oa, src_oa, sizeof(*req->rq_oi.oi_oa));
 812
 813                 /* XXX When we start creating objects on demand, we need to
 814                  *     make sure that we always create the object on the
 815                  *     stripe which holds the existing file size.
 816                  */
 817                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
 818                         req->rq_oi.oi_oa->o_size =
 819                                 lov_size_to_stripe(lsm, src_oa->o_size, i);
 820
 821                         CDEBUG(D_INODE, "stripe %d has size "LPU64"/"LPU64"\n",
 822                                i, req->rq_oi.oi_oa->o_size, src_oa->o_size);
 823                 }
 824
 825         }
 826         LASSERT(set->set_count == stripes);
 827
 828         if (stripes < lsm->lsm_stripe_count)
 829                 qos_shrink_lsm(set);
 830
 831         if (oti && (src_oa->o_valid & OBD_MD_FLCOOKIE)) {
 832                 oti_alloc_cookies(oti, set->set_count);
 833                 if (!oti->oti_logcookies)
 834                         GOTO(out_err, rc = -ENOMEM);
 835                 set->set_cookies = oti->oti_logcookies;
 836         }
 837 out_err:
 838         if (newea && rc)
 839                 obd_free_memmd(exp, &set->set_oi->oi_md);
 840         free_idx_array(idx_arr, idx_cnt);
 841         EXIT;
 842         return rc;
 843 }
 844
 845 void qos_update(struct lov_obd *lov, int idx, struct obd_statfs *osfs)
 846 {
 847         ENTRY;
 848         lov->lov_qos.lq_dirty = 1;
 849 }
 850