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[fs/lustre-release.git] / 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 /* #define QOS_DEBUG 1 */
41 #define D_QOS D_OTHER
42
43 #define TGT_BAVAIL(i)  (lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_bavail*\
44                         lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_bsize)
45 #define TGT_FFREE(i)   (lov->lov_tgts[i]->ltd_exp->exp_obd->obd_osfs.os_ffree)
46
47
48 int qos_add_tgt(struct obd_device *obd, __u32 index)
49 {
50         struct lov_obd *lov = &obd->u.lov;
51         struct lov_qos_oss *oss, *temposs;
52         struct obd_export *exp = lov->lov_tgts[index]->ltd_exp;
53         int rc = 0, found = 0;
54         ENTRY;
55
56         /* We only need this QOS struct on MDT, not clients - but we may not
57          * have registered the LOV's observer yet, so there's no way to know */
58         if (!exp || !exp->exp_connection) {
59                 CERROR("Missing connection\n");
60                 RETURN(-ENOTCONN);
61         }
62
63         down_write(&lov->lov_qos.lq_rw_sem);
64         mutex_down(&lov->lov_lock);
65         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
66                 if (obd_uuid_equals(&oss->lqo_uuid,
67                                     &exp->exp_connection->c_remote_uuid)) {
68                         found++;
69                         break;
70                 }
71         }
72
73         if (!found) {
74                 OBD_ALLOC_PTR(oss);
75                 if (!oss)
76                         GOTO(out, rc = -ENOMEM);
77                 memcpy(&oss->lqo_uuid,
78                        &exp->exp_connection->c_remote_uuid,
79                        sizeof(oss->lqo_uuid));
80         } else {
81                 /* Assume we have to move this one */
82                 list_del(&oss->lqo_oss_list);
83         }
84
85         oss->lqo_ost_count++;
86         lov->lov_tgts[index]->ltd_qos.ltq_oss = oss;
87
88         /* Add sorted by # of OSTs.  Find the first entry that we're
89            bigger than... */
90         list_for_each_entry(temposs, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
91                 if (oss->lqo_ost_count > temposs->lqo_ost_count)
92                         break;
93         }
94         /* ...and add before it.  If we're the first or smallest, temposs
95            points to the list head, and we add to the end. */
96         list_add_tail(&oss->lqo_oss_list, &temposs->lqo_oss_list);
97
98         lov->lov_qos.lq_dirty = 1;
99         lov->lov_qos.lq_dirty_rr = 1;
100
101         CDEBUG(D_QOS, "add tgt %s to OSS %s (%d OSTs)\n",
102                obd_uuid2str(&lov->lov_tgts[index]->ltd_uuid),
103                obd_uuid2str(&oss->lqo_uuid),
104                oss->lqo_ost_count);
105
106 out:
107         mutex_up(&lov->lov_lock);
108         up_write(&lov->lov_qos.lq_rw_sem);
109         RETURN(rc);
110 }
111
112 int qos_del_tgt(struct obd_device *obd, __u32 index)
113 {
114         struct lov_obd *lov = &obd->u.lov;
115         struct lov_qos_oss *oss;
116         int rc = 0;
117         ENTRY;
118
119         if (!lov->lov_tgts[index])
120                 RETURN(0);
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                         if (lov->lov_tgts[i]) 
207                             lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj <<= 1;
208         }
209
210         /* Per-OSS penalty is prio * oss_avail / oss_osts / (num_oss - 1) / 2 */
211         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
212                 temp = oss->lqo_bavail >> 1;
213                 do_div(temp, oss->lqo_ost_count * num_active);
214                 oss->lqo_penalty_per_obj = (temp * prio_wide) >> 8;
215                 if (lov->lov_qos.lq_reset == 0)
216                         oss->lqo_penalty = 0;
217         }
218
219         lov->lov_qos.lq_dirty = 0;
220         lov->lov_qos.lq_reset = 0;
221
222         /* If each ost has almost same free space,
223          * do rr allocation for better creation performance */
224         lov->lov_qos.lq_same_space = 0;
225         temp = ba_max - ba_min;
226         ba_min = (ba_min * 51) >> 8;     /* 51/256 = .20 */
227         if (temp < ba_min) {
228                 /* Difference is less than 20% */
229                 lov->lov_qos.lq_same_space = 1;
230                 /* Reset weights for the next time we enter qos mode */
231                 lov->lov_qos.lq_reset = 0;
232         }
233         rc = 0;
234
235 out:
236         if (!rc && lov->lov_qos.lq_same_space)
237                 RETURN(-EAGAIN);
238         RETURN(rc);
239 }
240
241 static int qos_calc_weight(struct lov_obd *lov, int i)
242 {
243         __u64 temp, temp2;
244
245         /* Final ost weight = TGT_BAVAIL - ost_penalty - oss_penalty */
246         temp = TGT_BAVAIL(i);
247         temp2 = lov->lov_tgts[i]->ltd_qos.ltq_penalty +
248                 lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty;
249         if (temp < temp2)
250                 lov->lov_tgts[i]->ltd_qos.ltq_weight = 0;
251         else
252                 lov->lov_tgts[i]->ltd_qos.ltq_weight = temp - temp2;
253         return 0;
254 }
255
256 /* We just used this index for a stripe; adjust everyone's weights */
257 static int qos_used(struct lov_obd *lov, __u32 index, __u64 *total_wt)
258 {
259         struct lov_qos_oss *oss;
260         int i;
261         ENTRY;
262
263         /* Don't allocate from this stripe anymore, until the next alloc_qos */
264         lov->lov_tgts[index]->ltd_qos.ltq_usable = 0;
265
266         oss = lov->lov_tgts[index]->ltd_qos.ltq_oss;
267
268         /* Decay old penalty by half (we're adding max penalty, and don't
269            want it to run away.) */
270         lov->lov_tgts[index]->ltd_qos.ltq_penalty >>= 1;
271         oss->lqo_penalty >>= 1;
272
273         /* Set max penalties for this OST and OSS */
274         lov->lov_tgts[index]->ltd_qos.ltq_penalty +=
275                 lov->lov_tgts[index]->ltd_qos.ltq_penalty_per_obj *
276                 lov->desc.ld_active_tgt_count;
277         oss->lqo_penalty += oss->lqo_penalty_per_obj *
278                 lov->lov_qos.lq_active_oss_count;
279
280         /* Decrease all OSS penalties */
281         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
282                 if (oss->lqo_penalty < oss->lqo_penalty_per_obj)
283                         oss->lqo_penalty = 0;
284                 else
285                         oss->lqo_penalty -= oss->lqo_penalty_per_obj;
286         }
287
288         *total_wt = 0;
289         /* Decrease all OST penalties */
290         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
291                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
292                         continue;
293                 if (lov->lov_tgts[i]->ltd_qos.ltq_penalty <
294                     lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj)
295                         lov->lov_tgts[i]->ltd_qos.ltq_penalty = 0;
296                 else
297                         lov->lov_tgts[i]->ltd_qos.ltq_penalty -=
298                         lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj;
299
300                 qos_calc_weight(lov, i);
301
302                 /* Recalc the total weight of usable osts */
303                 if (lov->lov_tgts[i]->ltd_qos.ltq_usable)
304                         *total_wt += lov->lov_tgts[i]->ltd_qos.ltq_weight;
305
306 #ifdef QOS_DEBUG
307                 CDEBUG(D_QOS, "recalc tgt %d avail="LPU64
308                        " ostppo="LPU64" ostp="LPU64" ossppo="LPU64
309                        " ossp="LPU64" wt="LPU64"\n",
310                        i, TGT_BAVAIL(i) >> 10,
311                        lov->lov_tgts[i]->ltd_qos.ltq_penalty_per_obj >> 10,
312                        lov->lov_tgts[i]->ltd_qos.ltq_penalty >> 10,
313                        lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty_per_obj>>10,
314                        lov->lov_tgts[i]->ltd_qos.ltq_oss->lqo_penalty>>10,
315                        lov->lov_tgts[i]->ltd_qos.ltq_weight>>10);
316 #endif
317         }
318
319         RETURN(0);
320 }
321
322 #define LOV_QOS_EMPTY ((__u32)-1)
323 /* compute optimal round-robin order, based on OSTs per OSS */
324 static int qos_calc_rr(struct lov_obd *lov)
325 {
326         struct lov_qos_oss *oss;
327         unsigned ost_count, placed, real_count;
328         int i;
329         ENTRY;
330
331         if (!lov->lov_qos.lq_dirty_rr) {
332                 LASSERT(lov->lov_qos.lq_rr_size);
333                 RETURN(0);
334         }
335
336         down_write(&lov->lov_qos.lq_rw_sem);
337         ost_count = lov->desc.ld_tgt_count;
338
339         if (lov->lov_qos.lq_rr_size)
340                 OBD_FREE(lov->lov_qos.lq_rr_array, lov->lov_qos.lq_rr_size);
341         lov->lov_qos.lq_rr_size = ost_count *
342                 sizeof(lov->lov_qos.lq_rr_array[0]);
343         OBD_ALLOC(lov->lov_qos.lq_rr_array, lov->lov_qos.lq_rr_size);
344         if (!lov->lov_qos.lq_rr_array) {
345                 lov->lov_qos.lq_rr_size = 0;
346                 up_write(&lov->lov_qos.lq_rw_sem);
347                 RETURN(-ENOMEM);
348         }
349
350         real_count = 0;
351         for (i = 0; i < ost_count; i++) {
352                 lov->lov_qos.lq_rr_array[i] = LOV_QOS_EMPTY;
353                 if (lov->lov_tgts[i])
354                         real_count++;
355         }
356
357         /* Place all the OSTs from 1 OSS at the same time. */
358         placed = 0;
359         list_for_each_entry(oss, &lov->lov_qos.lq_oss_list, lqo_oss_list) {
360                 int j = 0;
361                 for (i = 0; i < ost_count; i++) {
362                         if (lov->lov_tgts[i] &&
363                             (lov->lov_tgts[i]->ltd_qos.ltq_oss == oss)) {
364                               /* Evenly space these OSTs across arrayspace */
365                               int next = j * ost_count / oss->lqo_ost_count;
366                               while (lov->lov_qos.lq_rr_array[next] !=
367                                      LOV_QOS_EMPTY)
368                                       next = (next + 1) % ost_count;
369                               lov->lov_qos.lq_rr_array[next] = i;
370                               j++;
371                               placed++;
372                       }
373                 }
374                 LASSERT(j == oss->lqo_ost_count);
375         }
376
377         lov->lov_qos.lq_dirty_rr = 0;
378         up_write(&lov->lov_qos.lq_rw_sem);
379
380         if (placed != real_count) {
381                 /* This should never happen */
382                 LCONSOLE_ERROR_MSG(0x14e, "Failed to place all OSTs in the "
383                                    "round-robin list (%d of %d).\n", 
384                                    placed, real_count);
385                 for (i = 0; i < ost_count; i++) {
386                         LCONSOLE(D_WARNING, "rr #%d ost idx=%d\n", i,
387                                  lov->lov_qos.lq_rr_array[i]);
388                 }
389                 lov->lov_qos.lq_dirty_rr = 1;
390                 RETURN(-EAGAIN);
391         }
392
393 #ifdef QOS_DEBUG
394         for (i = 0; i < ost_count; i++) {
395                 LCONSOLE(D_QOS, "rr #%d ost idx=%d\n", i,
396                          lov->lov_qos.lq_rr_array[i]);
397         }
398 #endif
399
400         RETURN(0);
401 }
402
403
404 void qos_shrink_lsm(struct lov_request_set *set)
405 {
406         struct lov_stripe_md *lsm = set->set_oi->oi_md, *lsm_new;
407         /* XXX LOV STACKING call into osc for sizes */
408         unsigned oldsize, newsize;
409
410         if (set->set_oti && set->set_cookies && set->set_cookie_sent) {
411                 struct llog_cookie *cookies;
412                 oldsize = lsm->lsm_stripe_count * sizeof(*cookies);
413                 newsize = set->set_count * sizeof(*cookies);
414
415                 cookies = set->set_cookies;
416                 oti_alloc_cookies(set->set_oti, set->set_count);
417                 if (set->set_oti->oti_logcookies) {
418                         memcpy(set->set_oti->oti_logcookies, cookies, newsize);
419                         OBD_FREE(cookies, oldsize);
420                         set->set_cookies = set->set_oti->oti_logcookies;
421                 } else {
422                         CWARN("'leaking' %d bytes\n", oldsize - newsize);
423                 }
424         }
425
426         CWARN("using fewer stripes for object "LPU64": old %u new %u\n",
427               lsm->lsm_object_id, lsm->lsm_stripe_count, set->set_count);
428         LASSERT(lsm->lsm_stripe_count >= set->set_count);
429
430         newsize = lov_stripe_md_size(set->set_count);
431         OBD_ALLOC(lsm_new, newsize);
432         if (lsm_new != NULL) {
433                 int i;
434                 memcpy(lsm_new, lsm, sizeof(*lsm));
435                 for (i = 0; i < lsm->lsm_stripe_count; i++) {
436                         if (i < set->set_count) {
437                                 lsm_new->lsm_oinfo[i] = lsm->lsm_oinfo[i];
438                                 continue;
439                         }
440                         OBD_SLAB_FREE(lsm->lsm_oinfo[i], lov_oinfo_slab,
441                                       sizeof(struct lov_oinfo));
442                 }
443                 lsm_new->lsm_stripe_count = set->set_count;
444                 OBD_FREE(lsm, sizeof(struct lov_stripe_md) +
445                          lsm->lsm_stripe_count * sizeof(struct lov_oinfo *));
446                 set->set_oi->oi_md = lsm_new;
447         } else {
448                 CWARN("'leaking' few bytes\n");
449         }
450 }
451
452 int qos_remedy_create(struct lov_request_set *set, struct lov_request *req)
453 {
454         struct lov_stripe_md *lsm = set->set_oi->oi_md;
455         struct lov_obd *lov = &set->set_exp->exp_obd->u.lov;
456         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
457         int stripe, i, rc = -EIO;
458         ENTRY;
459
460         ost_idx = (req->rq_idx + lsm->lsm_stripe_count) % ost_count;
461         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
462                 if (!lov->lov_tgts[ost_idx] ||
463                     !lov->lov_tgts[ost_idx]->ltd_active)
464                         continue;
465                 /* check if objects has been created on this ost */
466                 for (stripe = 0; stripe < lsm->lsm_stripe_count; stripe++) {
467                         if (stripe == req->rq_stripe)
468                                 continue;
469                         if (ost_idx == lsm->lsm_oinfo[stripe]->loi_ost_idx)
470                                 break;
471                 }
472
473                 if (stripe >= lsm->lsm_stripe_count) {
474                         req->rq_idx = ost_idx;
475                         rc = obd_create(lov->lov_tgts[ost_idx]->ltd_exp,
476                                         req->rq_oi.oi_oa, &req->rq_oi.oi_md,
477                                         set->set_oti);
478                         if (!rc)
479                                 break;
480                 }
481         }
482         RETURN(rc);
483 }
484
485 static int min_stripe_count(int stripe_cnt, int flags)
486 {
487         return (flags & LOV_USES_DEFAULT_STRIPE ?
488                 stripe_cnt - (stripe_cnt / 4) : stripe_cnt);
489 }
490
491 #define LOV_CREATE_RESEED_MULT 4
492 #define LOV_CREATE_RESEED_MIN  1000
493 /* Allocate objects on osts with round-robin algorithm */
494 static int alloc_rr(struct lov_obd *lov, int *idx_arr, int *stripe_cnt,
495                     int flags)
496 {
497         unsigned array_idx, ost_count = lov->desc.ld_tgt_count;
498         unsigned ost_active_count = lov->desc.ld_active_tgt_count;
499         int i, *idx_pos;
500         __u32 ost_idx;
501         int ost_start_idx_temp;
502         int speed = 0;
503         int stripe_cnt_min = min_stripe_count(*stripe_cnt, flags);
504         ENTRY;
505
506         i = qos_calc_rr(lov);
507         if (i)
508                 RETURN(i);
509
510         if (--lov->lov_start_count <= 0) {
511                 lov->lov_start_idx = ll_rand() % ost_count;
512                 lov->lov_start_count =
513                         (LOV_CREATE_RESEED_MIN / max(ost_active_count, 1U) +
514                          LOV_CREATE_RESEED_MULT) * max(ost_active_count, 1U);
515         } else if (stripe_cnt_min >= ost_active_count ||
516                    lov->lov_start_idx > ost_count) {
517                 /* If we have allocated from all of the OSTs, slowly
518                    precess the next start */
519                 lov->lov_start_idx %= ost_count;
520                 if (*stripe_cnt > 1 && (ost_active_count % (*stripe_cnt) != 1))
521                         ++lov->lov_offset_idx;
522         }
523         down_read(&lov->lov_qos.lq_rw_sem);
524         ost_start_idx_temp = lov->lov_start_idx;
525
526 repeat_find :
527         array_idx = (lov->lov_start_idx + lov->lov_offset_idx) % ost_count;
528         idx_pos = idx_arr;
529 #ifdef QOS_DEBUG
530         CDEBUG(D_QOS, "want %d startidx %d startcnt %d offset %d arrayidx %d\n",
531                stripe_cnt_min, lov->lov_start_idx, lov->lov_start_count,
532                lov->lov_offset_idx, array_idx);
533 #endif
534
535         for (i = 0; i < ost_count; i++, array_idx=(array_idx + 1) % ost_count) {
536                 ++lov->lov_start_idx;
537                 ost_idx = lov->lov_qos.lq_rr_array[array_idx];
538 #ifdef QOS_DEBUG
539                 CDEBUG(D_QOS, "#%d strt %d act %d strp %d ary %d idx %d\n",
540                        i, lov->lov_start_idx,
541                        ((ost_idx != LOV_QOS_EMPTY) && lov->lov_tgts[ost_idx]) ?
542                        lov->lov_tgts[ost_idx]->ltd_active : 0,
543                        idx_pos - idx_arr, array_idx, ost_idx);
544 #endif
545                 if ((ost_idx == LOV_QOS_EMPTY) || !lov->lov_tgts[ost_idx] ||
546                     !lov->lov_tgts[ost_idx]->ltd_active)
547                         continue;
548
549                 /* Fail Check before osc_precreate() is called
550                    so we can only 'fail' single OSC. */
551                 if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) && ost_idx == 0)
552                         continue;
553
554                 /* Drop slow OSCs if we can */
555                 if (obd_precreate(lov->lov_tgts[ost_idx]->ltd_exp, speed == 0) >
556                     speed)
557                         continue;
558
559                 *idx_pos = ost_idx;
560                 idx_pos++;
561                 /* We have enough stripes */
562                 if (idx_pos - idx_arr == *stripe_cnt)
563                         break;
564         }
565         if ((speed < 2) && (idx_pos - idx_arr < stripe_cnt_min)) {
566                 /* Try again, allowing slower OSCs */
567                 speed++;
568                 lov->lov_start_idx = ost_start_idx_temp;
569                 goto repeat_find;
570         }
571
572         up_read(&lov->lov_qos.lq_rw_sem);
573
574         *stripe_cnt = idx_pos - idx_arr;
575         RETURN(0);
576 }
577
578 /* alloc objects on osts with specific stripe offset */
579 static int alloc_specific(struct lov_obd *lov, struct lov_stripe_md *lsm,
580                           int *idx_arr)
581 {
582         unsigned ost_idx, ost_count = lov->desc.ld_tgt_count;
583         int i, *idx_pos;
584         int speed = 0;
585         ENTRY;
586
587 repeat_find:
588         ost_idx = lsm->lsm_oinfo[0]->loi_ost_idx;
589         idx_pos = idx_arr;
590         for (i = 0; i < ost_count; i++, ost_idx = (ost_idx + 1) % ost_count) {
591                 if (!lov->lov_tgts[ost_idx] ||
592                     !lov->lov_tgts[ost_idx]->ltd_active) {
593                         continue;
594                 }
595
596                 /* Fail Check before osc_precreate() is called
597                    so we can only 'fail' single OSC. */
598                 if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) && ost_idx == 0)
599                         continue;
600
601                 /* Drop slow OSCs if we can */
602                 if (obd_precreate(lov->lov_tgts[ost_idx]->ltd_exp, speed == 0) >
603                     speed)
604                         continue;
605
606                 *idx_pos = ost_idx;
607                 idx_pos++;
608                 /* We have enough stripes */
609                 if (idx_pos - idx_arr == lsm->lsm_stripe_count)
610                         RETURN(0);
611         }
612         if (speed < 2) {
613                 /* Try again, allowing slower OSCs */
614                 speed++;
615                 goto repeat_find;
616         }
617
618         /* If we were passed specific striping params, then a failure to
619          * meet those requirements is an error, since we can't reallocate
620          * that memory (it might be part of a larger array or something).
621          *
622          * We can only get here if lsm_stripe_count was originally > 1.
623          */
624         CERROR("can't lstripe objid "LPX64": have "LPSZ" want %u\n",
625                lsm->lsm_object_id, idx_pos - idx_arr, lsm->lsm_stripe_count);
626         RETURN(-EFBIG);
627 }
628
629 /* Alloc objects on osts with optimization based on:
630    - free space
631    - network resources (shared OSS's)
632 */
633 static int alloc_qos(struct obd_export *exp, int *idx_arr, int *stripe_cnt,
634                      int flags)
635 {
636         struct lov_obd *lov = &exp->exp_obd->u.lov;
637         static time_t last_warn = 0;
638         time_t now = cfs_time_current_sec();
639         __u64 total_bavail, total_weight = 0;
640         __u32 ost_count;
641         int nfound, good_osts, i, warn = 0, rc = 0;
642         int stripe_cnt_min = min_stripe_count(*stripe_cnt, flags);
643         ENTRY;
644
645         if (stripe_cnt_min < 1)
646                 GOTO(out, rc = -EINVAL);
647
648         lov_getref(exp->exp_obd);
649         down_write(&lov->lov_qos.lq_rw_sem);
650
651         ost_count = lov->desc.ld_tgt_count;
652
653         if (lov->desc.ld_active_tgt_count < 2)
654                 GOTO(out, rc = -EAGAIN);
655
656         rc = qos_calc_ppo(exp->exp_obd);
657         if (rc)
658                 GOTO(out, rc);
659
660         total_bavail = 0;
661         good_osts = 0;
662         /* Warn users about zero available space/inode every 30 min */
663         if (cfs_time_sub(now, last_warn) > 60 * 30)
664                 warn = 1;
665         /* Find all the OSTs that are valid stripe candidates */
666         for (i = 0; i < ost_count; i++) {
667                 __u64 bavail;
668
669                 if (!lov->lov_tgts[i] || !lov->lov_tgts[i]->ltd_active)
670                         continue;
671                 bavail = TGT_BAVAIL(i);
672                 if (!bavail) {
673                         if (warn) {
674                                 CDEBUG(D_QOS, "no free space on %s\n",
675                                      obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
676                                 last_warn = now;
677                         }
678                         continue;
679                 }
680                 if (!TGT_FFREE(i)) {
681                         if (warn) {
682                                 CDEBUG(D_QOS, "no free inodes on %s\n",
683                                      obd_uuid2str(&lov->lov_tgts[i]->ltd_uuid));
684                                 last_warn = now;
685                         }
686                         continue;
687                 }
688
689                 /* Fail Check before osc_precreate() is called
690                    so we can only 'fail' single OSC. */
691                 if (OBD_FAIL_CHECK(OBD_FAIL_MDS_OSC_PRECREATE) && i == 0)
692                         continue;
693
694                 if (obd_precreate(lov->lov_tgts[i]->ltd_exp, 1) >= 2)
695                         continue;
696
697                 lov->lov_tgts[i]->ltd_qos.ltq_usable = 1;
698                 qos_calc_weight(lov, i);
699                 total_bavail += bavail;
700                 total_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
701
702                 good_osts++;
703         }
704
705         if (!total_bavail)
706                 GOTO(out, rc = -ENOSPC);
707
708         if (good_osts < stripe_cnt_min)
709                 GOTO(out, rc = -EAGAIN);
710
711         /* We have enough osts */
712         if (good_osts < *stripe_cnt)
713                 *stripe_cnt = good_osts;
714
715         /* Find enough OSTs with weighted random allocation. */
716         nfound = 0;
717         while (nfound < *stripe_cnt) {
718                 __u64 rand, cur_weight;
719
720                 cur_weight = 0;
721                 rc = -ENODEV;
722
723                 if (total_weight) {
724 #if BITS_PER_LONG == 32
725                         rand = ll_rand() % (unsigned)total_weight;
726                         /* If total_weight > 32-bit, first generate the high
727                          * 32 bits of the random number, then add in the low
728                          * 32 bits (truncated to the upper limit, if needed) */
729                         if (total_weight > 0xffffffffULL)
730                                 rand = (__u64)(ll_rand() %
731                                           (unsigned)(total_weight >> 32)) << 32;
732                         else
733                                 rand = 0;
734
735                         if (rand == (total_weight & 0xffffffff00000000ULL))
736                                 rand |= ll_rand() % (unsigned)total_weight;
737                         else
738                                 rand |= ll_rand();
739
740 #else
741                         rand = ((__u64)ll_rand() << 32 | ll_rand()) %
742                                 total_weight;
743 #endif
744                 } else {
745                         rand = 0;
746                 }
747
748                 /* On average, this will hit larger-weighted osts more often.
749                    0-weight osts will always get used last (only when rand=0).*/
750                 for (i = 0; i < ost_count; i++) {
751                         if (!lov->lov_tgts[i] ||
752                             !lov->lov_tgts[i]->ltd_qos.ltq_usable)
753                                 continue;
754
755                         cur_weight += lov->lov_tgts[i]->ltd_qos.ltq_weight;
756                         if (cur_weight >= rand) {
757 #ifdef QOS_DEBUG
758                                 CDEBUG(D_QOS, "assigned stripe=%d to idx=%d\n",
759                                        nfound, i);
760 #endif
761                                 idx_arr[nfound++] = i;
762                                 qos_used(lov, i, &total_weight);
763                                 rc = 0;
764                                 break;
765                         }
766                 }
767                 /* should never satisfy below condition */
768                 if (rc) {
769                         CERROR("Didn't find any OSTs?\n");
770                         break;
771                 }
772         }
773         LASSERT(nfound == *stripe_cnt);
774
775 out:
776         up_write(&lov->lov_qos.lq_rw_sem);
777
778         if (rc == -EAGAIN)
779                 rc = alloc_rr(lov, idx_arr, stripe_cnt, flags);
780
781         lov_putref(exp->exp_obd);
782         RETURN(rc);
783 }
784
785 /* return new alloced stripe count on success */
786 static int alloc_idx_array(struct obd_export *exp, struct lov_stripe_md *lsm,
787                            int newea, int **idx_arr, int *arr_cnt, int flags)
788 {
789         struct lov_obd *lov = &exp->exp_obd->u.lov;
790         int stripe_cnt = lsm->lsm_stripe_count;
791         int i, rc = 0;
792         int *tmp_arr = NULL;
793         ENTRY;
794
795         *arr_cnt = stripe_cnt;
796         OBD_ALLOC(tmp_arr, *arr_cnt * sizeof(int));
797         if (tmp_arr == NULL)
798                 RETURN(-ENOMEM);
799         for (i = 0; i < *arr_cnt; i++)
800                 tmp_arr[i] = -1;
801
802         if (newea ||
803             lsm->lsm_oinfo[0]->loi_ost_idx >= lov->desc.ld_tgt_count)
804                 rc = alloc_qos(exp, tmp_arr, &stripe_cnt, flags);
805         else
806                 rc = alloc_specific(lov, lsm, tmp_arr);
807
808         if (rc)
809                 GOTO(out_arr, rc);
810
811         *idx_arr = tmp_arr;
812         RETURN(stripe_cnt);
813 out_arr:
814         OBD_FREE(tmp_arr, *arr_cnt * sizeof(int));
815         *arr_cnt = 0;
816         RETURN(rc);
817 }
818
819 static void free_idx_array(int *idx_arr, int arr_cnt)
820 {
821         if (arr_cnt)
822                 OBD_FREE(idx_arr, arr_cnt * sizeof(int));
823 }
824
825 int qos_prep_create(struct obd_export *exp, struct lov_request_set *set)
826 {
827         struct lov_obd *lov = &exp->exp_obd->u.lov;
828         struct lov_stripe_md *lsm;
829         struct obdo *src_oa = set->set_oi->oi_oa;
830         struct obd_trans_info *oti = set->set_oti;
831         int i, stripes, rc = 0, newea = 0;
832         int flag = LOV_USES_ASSIGNED_STRIPE;
833         int *idx_arr = NULL, idx_cnt = 0;
834         ENTRY;
835
836         LASSERT(src_oa->o_valid & OBD_MD_FLID);
837
838         if (set->set_oi->oi_md == NULL) {
839                 int stripes_def = lov_get_stripecnt(lov, 0);
840
841                 /* If the MDS file was truncated up to some size, stripe over
842                  * enough OSTs to allow the file to be created at that size.
843                  * This may mean we use more than the default # of stripes. */
844                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
845                         obd_size min_bavail = LUSTRE_STRIPE_MAXBYTES;
846
847                         /* Find a small number of stripes we can use
848                            (up to # of active osts). */
849                         stripes = 1;
850                         lov_getref(exp->exp_obd);
851                         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
852                                 if (!lov->lov_tgts[i] ||
853                                     !lov->lov_tgts[i]->ltd_active)
854                                         continue;
855                                 min_bavail = min(min_bavail, TGT_BAVAIL(i));
856                                 if (min_bavail * stripes > src_oa->o_size)
857                                         break;
858                                 stripes++;
859                         }
860                         lov_putref(exp->exp_obd);
861
862                         if (stripes < stripes_def)
863                                 stripes = stripes_def;
864                 } else {
865                          flag = LOV_USES_DEFAULT_STRIPE;
866                          stripes = stripes_def;
867                 }
868
869                 rc = lov_alloc_memmd(&set->set_oi->oi_md, stripes,
870                                      lov->desc.ld_pattern ?
871                                      lov->desc.ld_pattern : LOV_PATTERN_RAID0,
872                                      LOV_MAGIC);
873                 if (rc < 0)
874                         GOTO(out_err, rc);
875                 newea = 1;
876                 rc = 0;
877         }
878
879         lsm = set->set_oi->oi_md;
880         lsm->lsm_object_id = src_oa->o_id;
881         if (!lsm->lsm_stripe_size)
882                 lsm->lsm_stripe_size = lov->desc.ld_default_stripe_size;
883         if (!lsm->lsm_pattern) {
884                 LASSERT(lov->desc.ld_pattern);
885                 lsm->lsm_pattern = lov->desc.ld_pattern;
886         }
887
888         stripes = alloc_idx_array(exp, lsm, newea, &idx_arr, &idx_cnt, flag);
889         if (stripes <= 0)
890                 GOTO(out_err, rc = stripes ? stripes : -EIO);
891         LASSERTF(stripes <= lsm->lsm_stripe_count,"requested %d allocated %d\n",
892                  lsm->lsm_stripe_count, stripes);
893
894         for (i = 0; i < stripes; i++) {
895                 struct lov_request *req;
896                 int ost_idx = idx_arr[i];
897                 LASSERT(ost_idx >= 0);
898
899                 OBD_ALLOC(req, sizeof(*req));
900                 if (req == NULL)
901                         GOTO(out_err, rc = -ENOMEM);
902                 lov_set_add_req(req, set);
903
904                 req->rq_buflen = sizeof(*req->rq_oi.oi_md);
905                 OBD_ALLOC(req->rq_oi.oi_md, req->rq_buflen);
906                 if (req->rq_oi.oi_md == NULL)
907                         GOTO(out_err, rc = -ENOMEM);
908
909                 OBDO_ALLOC(req->rq_oi.oi_oa);
910                 if (req->rq_oi.oi_oa == NULL)
911                         GOTO(out_err, rc = -ENOMEM);
912
913                 req->rq_idx = ost_idx;
914                 req->rq_stripe = i;
915                 /* create data objects with "parent" OA */
916                 memcpy(req->rq_oi.oi_oa, src_oa, sizeof(*req->rq_oi.oi_oa));
917
918                 /* XXX When we start creating objects on demand, we need to
919                  *     make sure that we always create the object on the
920                  *     stripe which holds the existing file size.
921                  */
922                 if (src_oa->o_valid & OBD_MD_FLSIZE) {
923                         req->rq_oi.oi_oa->o_size =
924                                 lov_size_to_stripe(lsm, src_oa->o_size, i);
925
926                         CDEBUG(D_INODE, "stripe %d has size "LPU64"/"LPU64"\n",
927                                i, req->rq_oi.oi_oa->o_size, src_oa->o_size);
928                 }
929
930         }
931         LASSERT(set->set_count == stripes);
932
933         if (stripes < lsm->lsm_stripe_count)
934                 qos_shrink_lsm(set);
935
936         if (oti && (src_oa->o_valid & OBD_MD_FLCOOKIE)) {
937                 oti_alloc_cookies(oti, set->set_count);
938                 if (!oti->oti_logcookies)
939                         GOTO(out_err, rc = -ENOMEM);
940                 set->set_cookies = oti->oti_logcookies;
941         }
942 out_err:
943         if (newea && rc)
944                 obd_free_memmd(exp, &set->set_oi->oi_md);
945         free_idx_array(idx_arr, idx_cnt);
946         EXIT;
947         return rc;
948 }
949
950 void qos_update(struct lov_obd *lov)
951 {
952         ENTRY;
953         lov->lov_qos.lq_dirty = 1;
954 }
955