drivers/staging/lustre/lustre/lov/lov_pool.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see [sun.com URL with a
  18  * copy of GPLv2].
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2012, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/lov/lov_pool.c
  37  *
  38  * OST pool methods
  39  *
  40  * Author: Jacques-Charles LAFOUCRIERE <jc.lafoucriere@cea.fr>
  41  * Author: Alex Lyashkov <Alexey.Lyashkov@Sun.COM>
  42  * Author: Nathaniel Rutman <Nathan.Rutman@Sun.COM>
  43  */
  44
  45 #define DEBUG_SUBSYSTEM S_LOV
  46
  47 #include "../../include/linux/libcfs/libcfs.h"
  48
  49 #include "../include/obd.h"
  50 #include "lov_internal.h"
  51
  52 #define pool_tgt(_p, _i) \
  53                 _p->pool_lobd->u.lov.lov_tgts[_p->pool_obds.op_array[_i]]
  54
  55 static void lov_pool_getref(struct pool_desc *pool)
  56 {
  57         CDEBUG(D_INFO, "pool %p\n", pool);
  58         atomic_inc(&pool->pool_refcount);
  59 }
  60
  61 void lov_pool_putref(struct pool_desc *pool)
  62 {
  63         CDEBUG(D_INFO, "pool %p\n", pool);
  64         if (atomic_dec_and_test(&pool->pool_refcount)) {
  65                 LASSERT(hlist_unhashed(&pool->pool_hash));
  66                 LASSERT(list_empty(&pool->pool_list));
  67                 LASSERT(pool->pool_proc_entry == NULL);
  68                 lov_ost_pool_free(&(pool->pool_rr.lqr_pool));
  69                 lov_ost_pool_free(&(pool->pool_obds));
  70                 OBD_FREE_PTR(pool);
  71         }
  72 }
  73
  74 void lov_pool_putref_locked(struct pool_desc *pool)
  75 {
  76         CDEBUG(D_INFO, "pool %p\n", pool);
  77         LASSERT(atomic_read(&pool->pool_refcount) > 1);
  78
  79         atomic_dec(&pool->pool_refcount);
  80 }
  81
  82 /*
  83  * hash function using a Rotating Hash algorithm
  84  * Knuth, D. The Art of Computer Programming,
  85  * Volume 3: Sorting and Searching,
  86  * Chapter 6.4.
  87  * Addison Wesley, 1973
  88  */
  89 static __u32 pool_hashfn(struct cfs_hash *hash_body, const void *key, unsigned mask)
  90 {
  91         int i;
  92         __u32 result;
  93         char *poolname;
  94
  95         result = 0;
  96         poolname = (char *)key;
  97         for (i = 0; i < LOV_MAXPOOLNAME; i++) {
  98                 if (poolname[i] == '\0')
  99                         break;
 100                 result = (result << 4)^(result >> 28) ^  poolname[i];
 101         }
 102         return (result % mask);
 103 }
 104
 105 static void *pool_key(struct hlist_node *hnode)
 106 {
 107         struct pool_desc *pool;
 108
 109         pool = hlist_entry(hnode, struct pool_desc, pool_hash);
 110         return (pool->pool_name);
 111 }
 112
 113 static int pool_hashkey_keycmp(const void *key, struct hlist_node *compared_hnode)
 114 {
 115         char *pool_name;
 116         struct pool_desc *pool;
 117
 118         pool_name = (char *)key;
 119         pool = hlist_entry(compared_hnode, struct pool_desc, pool_hash);
 120         return !strncmp(pool_name, pool->pool_name, LOV_MAXPOOLNAME);
 121 }
 122
 123 static void *pool_hashobject(struct hlist_node *hnode)
 124 {
 125         return hlist_entry(hnode, struct pool_desc, pool_hash);
 126 }
 127
 128 static void pool_hashrefcount_get(struct cfs_hash *hs, struct hlist_node *hnode)
 129 {
 130         struct pool_desc *pool;
 131
 132         pool = hlist_entry(hnode, struct pool_desc, pool_hash);
 133         lov_pool_getref(pool);
 134 }
 135
 136 static void pool_hashrefcount_put_locked(struct cfs_hash *hs,
 137                                          struct hlist_node *hnode)
 138 {
 139         struct pool_desc *pool;
 140
 141         pool = hlist_entry(hnode, struct pool_desc, pool_hash);
 142         lov_pool_putref_locked(pool);
 143 }
 144
 145 cfs_hash_ops_t pool_hash_operations = {
 146         .hs_hash        = pool_hashfn,
 147         .hs_key  = pool_key,
 148         .hs_keycmp      = pool_hashkey_keycmp,
 149         .hs_object      = pool_hashobject,
 150         .hs_get  = pool_hashrefcount_get,
 151         .hs_put_locked  = pool_hashrefcount_put_locked,
 152
 153 };
 154
 155 #if defined (CONFIG_PROC_FS)
 156 /* ifdef needed for liblustre support */
 157 /*
 158  * pool /proc seq_file methods
 159  */
 160 /*
 161  * iterator is used to go through the target pool entries
 162  * index is the current entry index in the lp_array[] array
 163  * index >= pos returned to the seq_file interface
 164  * pos is from 0 to (pool->pool_obds.op_count - 1)
 165  */
 166 #define POOL_IT_MAGIC 0xB001CEA0
 167 struct pool_iterator {
 168         int magic;
 169         struct pool_desc *pool;
 170         int idx;        /* from 0 to pool_tgt_size - 1 */
 171 };
 172
 173 static void *pool_proc_next(struct seq_file *s, void *v, loff_t *pos)
 174 {
 175         struct pool_iterator *iter = (struct pool_iterator *)s->private;
 176         int prev_idx;
 177
 178         LASSERTF(iter->magic == POOL_IT_MAGIC, "%08X", iter->magic);
 179
 180         /* test if end of file */
 181         if (*pos >= pool_tgt_count(iter->pool))
 182                 return NULL;
 183
 184         /* iterate to find a non empty entry */
 185         prev_idx = iter->idx;
 186         down_read(&pool_tgt_rw_sem(iter->pool));
 187         iter->idx++;
 188         if (iter->idx == pool_tgt_count(iter->pool)) {
 189                 iter->idx = prev_idx; /* we stay on the last entry */
 190                 up_read(&pool_tgt_rw_sem(iter->pool));
 191                 return NULL;
 192         }
 193         up_read(&pool_tgt_rw_sem(iter->pool));
 194         (*pos)++;
 195         /* return != NULL to continue */
 196         return iter;
 197 }
 198
 199 static void *pool_proc_start(struct seq_file *s, loff_t *pos)
 200 {
 201         struct pool_desc *pool = (struct pool_desc *)s->private;
 202         struct pool_iterator *iter;
 203
 204         lov_pool_getref(pool);
 205         if ((pool_tgt_count(pool) == 0) ||
 206             (*pos >= pool_tgt_count(pool))) {
 207                 /* iter is not created, so stop() has no way to
 208                  * find pool to dec ref */
 209                 lov_pool_putref(pool);
 210                 return NULL;
 211         }
 212
 213         OBD_ALLOC_PTR(iter);
 214         if (!iter)
 215                 return ERR_PTR(-ENOMEM);
 216         iter->magic = POOL_IT_MAGIC;
 217         iter->pool = pool;
 218         iter->idx = 0;
 219
 220         /* we use seq_file private field to memorized iterator so
 221          * we can free it at stop() */
 222         /* /!\ do not forget to restore it to pool before freeing it */
 223         s->private = iter;
 224         if (*pos > 0) {
 225                 loff_t i;
 226                 void *ptr;
 227
 228                 i = 0;
 229                 do {
 230                      ptr = pool_proc_next(s, &iter, &i);
 231                 } while ((i < *pos) && (ptr != NULL));
 232                 return ptr;
 233         }
 234         return iter;
 235 }
 236
 237 static void pool_proc_stop(struct seq_file *s, void *v)
 238 {
 239         struct pool_iterator *iter = (struct pool_iterator *)s->private;
 240
 241         /* in some cases stop() method is called 2 times, without
 242          * calling start() method (see seq_read() from fs/seq_file.c)
 243          * we have to free only if s->private is an iterator */
 244         if ((iter) && (iter->magic == POOL_IT_MAGIC)) {
 245                 /* we restore s->private so next call to pool_proc_start()
 246                  * will work */
 247                 s->private = iter->pool;
 248                 lov_pool_putref(iter->pool);
 249                 OBD_FREE_PTR(iter);
 250         }
 251         return;
 252 }
 253
 254 static int pool_proc_show(struct seq_file *s, void *v)
 255 {
 256         struct pool_iterator *iter = (struct pool_iterator *)v;
 257         struct lov_tgt_desc *tgt;
 258
 259         LASSERTF(iter->magic == POOL_IT_MAGIC, "%08X", iter->magic);
 260         LASSERT(iter->pool != NULL);
 261         LASSERT(iter->idx <= pool_tgt_count(iter->pool));
 262
 263         down_read(&pool_tgt_rw_sem(iter->pool));
 264         tgt = pool_tgt(iter->pool, iter->idx);
 265         up_read(&pool_tgt_rw_sem(iter->pool));
 266         if (tgt)
 267                 seq_printf(s, "%s\n", obd_uuid2str(&(tgt->ltd_uuid)));
 268
 269         return 0;
 270 }
 271
 272 static struct seq_operations pool_proc_ops = {
 273         .start    = pool_proc_start,
 274         .next      = pool_proc_next,
 275         .stop      = pool_proc_stop,
 276         .show      = pool_proc_show,
 277 };
 278
 279 static int pool_proc_open(struct inode *inode, struct file *file)
 280 {
 281         int rc;
 282
 283         rc = seq_open(file, &pool_proc_ops);
 284         if (!rc) {
 285                 struct seq_file *s = file->private_data;
 286                 s->private = PDE_DATA(inode);
 287         }
 288         return rc;
 289 }
 290
 291 static struct file_operations pool_proc_operations = {
 292         .open      = pool_proc_open,
 293         .read      = seq_read,
 294         .llseek  = seq_lseek,
 295         .release        = seq_release,
 296 };
 297 #endif /* CONFIG_PROC_FS */
 298
 299 void lov_dump_pool(int level, struct pool_desc *pool)
 300 {
 301         int i;
 302
 303         lov_pool_getref(pool);
 304
 305         CDEBUG(level, "pool "LOV_POOLNAMEF" has %d members\n",
 306                pool->pool_name, pool->pool_obds.op_count);
 307         down_read(&pool_tgt_rw_sem(pool));
 308
 309         for (i = 0; i < pool_tgt_count(pool) ; i++) {
 310                 if (!pool_tgt(pool, i) || !(pool_tgt(pool, i))->ltd_exp)
 311                         continue;
 312                 CDEBUG(level, "pool "LOV_POOLNAMEF"[%d] = %s\n",
 313                        pool->pool_name, i,
 314                        obd_uuid2str(&((pool_tgt(pool, i))->ltd_uuid)));
 315         }
 316
 317         up_read(&pool_tgt_rw_sem(pool));
 318         lov_pool_putref(pool);
 319 }
 320
 321 #define LOV_POOL_INIT_COUNT 2
 322 int lov_ost_pool_init(struct ost_pool *op, unsigned int count)
 323 {
 324         if (count == 0)
 325                 count = LOV_POOL_INIT_COUNT;
 326         op->op_array = NULL;
 327         op->op_count = 0;
 328         init_rwsem(&op->op_rw_sem);
 329         op->op_size = count;
 330         OBD_ALLOC(op->op_array, op->op_size * sizeof(op->op_array[0]));
 331         if (op->op_array == NULL) {
 332                 op->op_size = 0;
 333                 return -ENOMEM;
 334         }
 335         return 0;
 336 }
 337
 338 /* Caller must hold write op_rwlock */
 339 int lov_ost_pool_extend(struct ost_pool *op, unsigned int min_count)
 340 {
 341         __u32 *new;
 342         int new_size;
 343
 344         LASSERT(min_count != 0);
 345
 346         if (op->op_count < op->op_size)
 347                 return 0;
 348
 349         new_size = max(min_count, 2 * op->op_size);
 350         OBD_ALLOC(new, new_size * sizeof(op->op_array[0]));
 351         if (new == NULL)
 352                 return -ENOMEM;
 353
 354         /* copy old array to new one */
 355         memcpy(new, op->op_array, op->op_size * sizeof(op->op_array[0]));
 356         OBD_FREE(op->op_array, op->op_size * sizeof(op->op_array[0]));
 357         op->op_array = new;
 358         op->op_size = new_size;
 359         return 0;
 360 }
 361
 362 int lov_ost_pool_add(struct ost_pool *op, __u32 idx, unsigned int min_count)
 363 {
 364         int rc = 0, i;
 365
 366         down_write(&op->op_rw_sem);
 367
 368         rc = lov_ost_pool_extend(op, min_count);
 369         if (rc)
 370                 GOTO(out, rc);
 371
 372         /* search ost in pool array */
 373         for (i = 0; i < op->op_count; i++) {
 374                 if (op->op_array[i] == idx)
 375                         GOTO(out, rc = -EEXIST);
 376         }
 377         /* ost not found we add it */
 378         op->op_array[op->op_count] = idx;
 379         op->op_count++;
 380 out:
 381         up_write(&op->op_rw_sem);
 382         return rc;
 383 }
 384
 385 int lov_ost_pool_remove(struct ost_pool *op, __u32 idx)
 386 {
 387         int i;
 388
 389         down_write(&op->op_rw_sem);
 390
 391         for (i = 0; i < op->op_count; i++) {
 392                 if (op->op_array[i] == idx) {
 393                         memmove(&op->op_array[i], &op->op_array[i + 1],
 394                                 (op->op_count - i - 1) * sizeof(op->op_array[0]));
 395                         op->op_count--;
 396                         up_write(&op->op_rw_sem);
 397                         return 0;
 398                 }
 399         }
 400
 401         up_write(&op->op_rw_sem);
 402         return -EINVAL;
 403 }
 404
 405 int lov_ost_pool_free(struct ost_pool *op)
 406 {
 407         if (op->op_size == 0)
 408                 return 0;
 409
 410         down_write(&op->op_rw_sem);
 411
 412         OBD_FREE(op->op_array, op->op_size * sizeof(op->op_array[0]));
 413         op->op_array = NULL;
 414         op->op_count = 0;
 415         op->op_size = 0;
 416
 417         up_write(&op->op_rw_sem);
 418         return 0;
 419 }
 420
 421
 422 int lov_pool_new(struct obd_device *obd, char *poolname)
 423 {
 424         struct lov_obd *lov;
 425         struct pool_desc *new_pool;
 426         int rc;
 427
 428         lov = &(obd->u.lov);
 429
 430         if (strlen(poolname) > LOV_MAXPOOLNAME)
 431                 return -ENAMETOOLONG;
 432
 433         OBD_ALLOC_PTR(new_pool);
 434         if (new_pool == NULL)
 435                 return -ENOMEM;
 436
 437         strncpy(new_pool->pool_name, poolname, LOV_MAXPOOLNAME);
 438         new_pool->pool_name[LOV_MAXPOOLNAME] = '\0';
 439         new_pool->pool_lobd = obd;
 440         /* ref count init to 1 because when created a pool is always used
 441          * up to deletion
 442          */
 443         atomic_set(&new_pool->pool_refcount, 1);
 444         rc = lov_ost_pool_init(&new_pool->pool_obds, 0);
 445         if (rc)
 446                GOTO(out_err, rc);
 447
 448         memset(&(new_pool->pool_rr), 0, sizeof(struct lov_qos_rr));
 449         rc = lov_ost_pool_init(&new_pool->pool_rr.lqr_pool, 0);
 450         if (rc)
 451                 GOTO(out_free_pool_obds, rc);
 452
 453         INIT_HLIST_NODE(&new_pool->pool_hash);
 454
 455 #if defined (CONFIG_PROC_FS)
 456         /* we need this assert seq_file is not implemented for liblustre */
 457         /* get ref for /proc file */
 458         lov_pool_getref(new_pool);
 459         new_pool->pool_proc_entry = lprocfs_add_simple(lov->lov_pool_proc_entry,
 460                                                        poolname, new_pool,
 461                                                        &pool_proc_operations);
 462         if (IS_ERR(new_pool->pool_proc_entry)) {
 463                 CWARN("Cannot add proc pool entry "LOV_POOLNAMEF"\n", poolname);
 464                 new_pool->pool_proc_entry = NULL;
 465                 lov_pool_putref(new_pool);
 466         }
 467         CDEBUG(D_INFO, "pool %p - proc %p\n", new_pool, new_pool->pool_proc_entry);
 468 #endif
 469
 470         spin_lock(&obd->obd_dev_lock);
 471         list_add_tail(&new_pool->pool_list, &lov->lov_pool_list);
 472         lov->lov_pool_count++;
 473         spin_unlock(&obd->obd_dev_lock);
 474
 475         /* add to find only when it fully ready  */
 476         rc = cfs_hash_add_unique(lov->lov_pools_hash_body, poolname,
 477                                  &new_pool->pool_hash);
 478         if (rc)
 479                 GOTO(out_err, rc = -EEXIST);
 480
 481         CDEBUG(D_CONFIG, LOV_POOLNAMEF" is pool #%d\n",
 482                poolname, lov->lov_pool_count);
 483
 484         return 0;
 485
 486 out_err:
 487         spin_lock(&obd->obd_dev_lock);
 488         list_del_init(&new_pool->pool_list);
 489         lov->lov_pool_count--;
 490         spin_unlock(&obd->obd_dev_lock);
 491
 492         lprocfs_remove(&new_pool->pool_proc_entry);
 493
 494         lov_ost_pool_free(&new_pool->pool_rr.lqr_pool);
 495 out_free_pool_obds:
 496         lov_ost_pool_free(&new_pool->pool_obds);
 497         OBD_FREE_PTR(new_pool);
 498         return rc;
 499 }
 500
 501 int lov_pool_del(struct obd_device *obd, char *poolname)
 502 {
 503         struct lov_obd *lov;
 504         struct pool_desc *pool;
 505
 506         lov = &(obd->u.lov);
 507
 508         /* lookup and kill hash reference */
 509         pool = cfs_hash_del_key(lov->lov_pools_hash_body, poolname);
 510         if (pool == NULL)
 511                 return -ENOENT;
 512
 513         if (pool->pool_proc_entry != NULL) {
 514                 CDEBUG(D_INFO, "proc entry %p\n", pool->pool_proc_entry);
 515                 lprocfs_remove(&pool->pool_proc_entry);
 516                 lov_pool_putref(pool);
 517         }
 518
 519         spin_lock(&obd->obd_dev_lock);
 520         list_del_init(&pool->pool_list);
 521         lov->lov_pool_count--;
 522         spin_unlock(&obd->obd_dev_lock);
 523
 524         /* release last reference */
 525         lov_pool_putref(pool);
 526
 527         return 0;
 528 }
 529
 530
 531 int lov_pool_add(struct obd_device *obd, char *poolname, char *ostname)
 532 {
 533         struct obd_uuid ost_uuid;
 534         struct lov_obd *lov;
 535         struct pool_desc *pool;
 536         unsigned int lov_idx;
 537         int rc;
 538
 539         lov = &(obd->u.lov);
 540
 541         pool = cfs_hash_lookup(lov->lov_pools_hash_body, poolname);
 542         if (pool == NULL)
 543                 return -ENOENT;
 544
 545         obd_str2uuid(&ost_uuid, ostname);
 546
 547
 548         /* search ost in lov array */
 549         obd_getref(obd);
 550         for (lov_idx = 0; lov_idx < lov->desc.ld_tgt_count; lov_idx++) {
 551                 if (!lov->lov_tgts[lov_idx])
 552                         continue;
 553                 if (obd_uuid_equals(&ost_uuid,
 554                                     &(lov->lov_tgts[lov_idx]->ltd_uuid)))
 555                         break;
 556         }
 557         /* test if ost found in lov */
 558         if (lov_idx == lov->desc.ld_tgt_count)
 559                 GOTO(out, rc = -EINVAL);
 560
 561         rc = lov_ost_pool_add(&pool->pool_obds, lov_idx, lov->lov_tgt_size);
 562         if (rc)
 563                 GOTO(out, rc);
 564
 565         pool->pool_rr.lqr_dirty = 1;
 566
 567         CDEBUG(D_CONFIG, "Added %s to "LOV_POOLNAMEF" as member %d\n",
 568                ostname, poolname,  pool_tgt_count(pool));
 569
 570 out:
 571         obd_putref(obd);
 572         lov_pool_putref(pool);
 573         return rc;
 574 }
 575
 576 int lov_pool_remove(struct obd_device *obd, char *poolname, char *ostname)
 577 {
 578         struct obd_uuid ost_uuid;
 579         struct lov_obd *lov;
 580         struct pool_desc *pool;
 581         unsigned int lov_idx;
 582         int rc = 0;
 583
 584         lov = &(obd->u.lov);
 585
 586         pool = cfs_hash_lookup(lov->lov_pools_hash_body, poolname);
 587         if (pool == NULL)
 588                 return -ENOENT;
 589
 590         obd_str2uuid(&ost_uuid, ostname);
 591
 592         obd_getref(obd);
 593         /* search ost in lov array, to get index */
 594         for (lov_idx = 0; lov_idx < lov->desc.ld_tgt_count; lov_idx++) {
 595                 if (!lov->lov_tgts[lov_idx])
 596                         continue;
 597
 598                 if (obd_uuid_equals(&ost_uuid,
 599                                     &(lov->lov_tgts[lov_idx]->ltd_uuid)))
 600                         break;
 601         }
 602
 603         /* test if ost found in lov */
 604         if (lov_idx == lov->desc.ld_tgt_count)
 605                 GOTO(out, rc = -EINVAL);
 606
 607         lov_ost_pool_remove(&pool->pool_obds, lov_idx);
 608
 609         pool->pool_rr.lqr_dirty = 1;
 610
 611         CDEBUG(D_CONFIG, "%s removed from "LOV_POOLNAMEF"\n", ostname,
 612                poolname);
 613
 614 out:
 615         obd_putref(obd);
 616         lov_pool_putref(pool);
 617         return rc;
 618 }
 619
 620 int lov_check_index_in_pool(__u32 idx, struct pool_desc *pool)
 621 {
 622         int i, rc;
 623
 624         /* caller may no have a ref on pool if it got the pool
 625          * without calling lov_find_pool() (e.g. go through the lov pool
 626          * list)
 627          */
 628         lov_pool_getref(pool);
 629
 630         down_read(&pool_tgt_rw_sem(pool));
 631
 632         for (i = 0; i < pool_tgt_count(pool); i++) {
 633                 if (pool_tgt_array(pool)[i] == idx)
 634                         GOTO(out, rc = 0);
 635         }
 636         rc = -ENOENT;
 637 out:
 638         up_read(&pool_tgt_rw_sem(pool));
 639
 640         lov_pool_putref(pool);
 641         return rc;
 642 }
 643
 644 struct pool_desc *lov_find_pool(struct lov_obd *lov, char *poolname)
 645 {
 646         struct pool_desc *pool;
 647
 648         pool = NULL;
 649         if (poolname[0] != '\0') {
 650                 pool = cfs_hash_lookup(lov->lov_pools_hash_body, poolname);
 651                 if (pool == NULL)
 652                         CWARN("Request for an unknown pool ("LOV_POOLNAMEF")\n",
 653                               poolname);
 654                 if ((pool != NULL) && (pool_tgt_count(pool) == 0)) {
 655                         CWARN("Request for an empty pool ("LOV_POOLNAMEF")\n",
 656                                poolname);
 657                         /* pool is ignored, so we remove ref on it */
 658                         lov_pool_putref(pool);
 659                         pool = NULL;
 660                 }
 661         }
 662         return pool;
 663 }