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 
lov_pool_getref(struct pool_desc * pool)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 
lov_pool_putref(struct pool_desc * pool)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 
lov_pool_putref_locked(struct pool_desc * pool)74 static 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  */
pool_hashfn(struct cfs_hash * hash_body,const void * key,unsigned mask)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 
pool_key(struct hlist_node * hnode)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 
pool_hashkey_keycmp(const void * key,struct hlist_node * compared_hnode)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 
pool_hashobject(struct hlist_node * hnode)123 static void *pool_hashobject(struct hlist_node *hnode)
124 {
125 	return hlist_entry(hnode, struct pool_desc, pool_hash);
126 }
127 
pool_hashrefcount_get(struct cfs_hash * hs,struct hlist_node * hnode)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 
pool_hashrefcount_put_locked(struct cfs_hash * hs,struct hlist_node * hnode)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 
pool_proc_next(struct seq_file * s,void * v,loff_t * pos)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 
pool_proc_start(struct seq_file * s,loff_t * pos)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 
pool_proc_stop(struct seq_file * s,void * v)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 
pool_proc_show(struct seq_file * s,void * v)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 
pool_proc_open(struct inode * inode,struct file * file)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 
lov_dump_pool(int level,struct pool_desc * pool)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
lov_ost_pool_init(struct ost_pool * op,unsigned int count)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 */
lov_ost_pool_extend(struct ost_pool * op,unsigned int min_count)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 
lov_ost_pool_add(struct ost_pool * op,__u32 idx,unsigned int min_count)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;
371 
372 	/* search ost in pool array */
373 	for (i = 0; i < op->op_count; i++) {
374 		if (op->op_array[i] == idx) {
375 			rc = -EEXIST;
376 			goto out;
377 		}
378 	}
379 	/* ost not found we add it */
380 	op->op_array[op->op_count] = idx;
381 	op->op_count++;
382 out:
383 	up_write(&op->op_rw_sem);
384 	return rc;
385 }
386 
lov_ost_pool_remove(struct ost_pool * op,__u32 idx)387 int lov_ost_pool_remove(struct ost_pool *op, __u32 idx)
388 {
389 	int i;
390 
391 	down_write(&op->op_rw_sem);
392 
393 	for (i = 0; i < op->op_count; i++) {
394 		if (op->op_array[i] == idx) {
395 			memmove(&op->op_array[i], &op->op_array[i + 1],
396 				(op->op_count - i - 1) * sizeof(op->op_array[0]));
397 			op->op_count--;
398 			up_write(&op->op_rw_sem);
399 			return 0;
400 		}
401 	}
402 
403 	up_write(&op->op_rw_sem);
404 	return -EINVAL;
405 }
406 
lov_ost_pool_free(struct ost_pool * op)407 int lov_ost_pool_free(struct ost_pool *op)
408 {
409 	if (op->op_size == 0)
410 		return 0;
411 
412 	down_write(&op->op_rw_sem);
413 
414 	OBD_FREE(op->op_array, op->op_size * sizeof(op->op_array[0]));
415 	op->op_array = NULL;
416 	op->op_count = 0;
417 	op->op_size = 0;
418 
419 	up_write(&op->op_rw_sem);
420 	return 0;
421 }
422 
423 
lov_pool_new(struct obd_device * obd,char * poolname)424 int lov_pool_new(struct obd_device *obd, char *poolname)
425 {
426 	struct lov_obd *lov;
427 	struct pool_desc *new_pool;
428 	int rc;
429 
430 	lov = &(obd->u.lov);
431 
432 	if (strlen(poolname) > LOV_MAXPOOLNAME)
433 		return -ENAMETOOLONG;
434 
435 	OBD_ALLOC_PTR(new_pool);
436 	if (new_pool == NULL)
437 		return -ENOMEM;
438 
439 	strncpy(new_pool->pool_name, poolname, LOV_MAXPOOLNAME);
440 	new_pool->pool_name[LOV_MAXPOOLNAME] = '\0';
441 	new_pool->pool_lobd = obd;
442 	/* ref count init to 1 because when created a pool is always used
443 	 * up to deletion
444 	 */
445 	atomic_set(&new_pool->pool_refcount, 1);
446 	rc = lov_ost_pool_init(&new_pool->pool_obds, 0);
447 	if (rc)
448 		goto out_err;
449 
450 	memset(&(new_pool->pool_rr), 0, sizeof(struct lov_qos_rr));
451 	rc = lov_ost_pool_init(&new_pool->pool_rr.lqr_pool, 0);
452 	if (rc)
453 		goto out_free_pool_obds;
454 
455 	INIT_HLIST_NODE(&new_pool->pool_hash);
456 
457 #if defined (CONFIG_PROC_FS)
458 	/* we need this assert seq_file is not implemented for liblustre */
459 	/* get ref for /proc file */
460 	lov_pool_getref(new_pool);
461 	new_pool->pool_proc_entry = lprocfs_add_simple(lov->lov_pool_proc_entry,
462 						       poolname, new_pool,
463 						       &pool_proc_operations);
464 	if (IS_ERR(new_pool->pool_proc_entry)) {
465 		CWARN("Cannot add proc pool entry "LOV_POOLNAMEF"\n", poolname);
466 		new_pool->pool_proc_entry = NULL;
467 		lov_pool_putref(new_pool);
468 	}
469 	CDEBUG(D_INFO, "pool %p - proc %p\n", new_pool, new_pool->pool_proc_entry);
470 #endif
471 
472 	spin_lock(&obd->obd_dev_lock);
473 	list_add_tail(&new_pool->pool_list, &lov->lov_pool_list);
474 	lov->lov_pool_count++;
475 	spin_unlock(&obd->obd_dev_lock);
476 
477 	/* add to find only when it fully ready  */
478 	rc = cfs_hash_add_unique(lov->lov_pools_hash_body, poolname,
479 				 &new_pool->pool_hash);
480 	if (rc) {
481 		rc = -EEXIST;
482 		goto out_err;
483 	}
484 
485 	CDEBUG(D_CONFIG, LOV_POOLNAMEF" is pool #%d\n",
486 	       poolname, lov->lov_pool_count);
487 
488 	return 0;
489 
490 out_err:
491 	spin_lock(&obd->obd_dev_lock);
492 	list_del_init(&new_pool->pool_list);
493 	lov->lov_pool_count--;
494 	spin_unlock(&obd->obd_dev_lock);
495 
496 	lprocfs_remove(&new_pool->pool_proc_entry);
497 
498 	lov_ost_pool_free(&new_pool->pool_rr.lqr_pool);
499 out_free_pool_obds:
500 	lov_ost_pool_free(&new_pool->pool_obds);
501 	OBD_FREE_PTR(new_pool);
502 	return rc;
503 }
504 
lov_pool_del(struct obd_device * obd,char * poolname)505 int lov_pool_del(struct obd_device *obd, char *poolname)
506 {
507 	struct lov_obd *lov;
508 	struct pool_desc *pool;
509 
510 	lov = &(obd->u.lov);
511 
512 	/* lookup and kill hash reference */
513 	pool = cfs_hash_del_key(lov->lov_pools_hash_body, poolname);
514 	if (pool == NULL)
515 		return -ENOENT;
516 
517 	if (pool->pool_proc_entry != NULL) {
518 		CDEBUG(D_INFO, "proc entry %p\n", pool->pool_proc_entry);
519 		lprocfs_remove(&pool->pool_proc_entry);
520 		lov_pool_putref(pool);
521 	}
522 
523 	spin_lock(&obd->obd_dev_lock);
524 	list_del_init(&pool->pool_list);
525 	lov->lov_pool_count--;
526 	spin_unlock(&obd->obd_dev_lock);
527 
528 	/* release last reference */
529 	lov_pool_putref(pool);
530 
531 	return 0;
532 }
533 
534 
lov_pool_add(struct obd_device * obd,char * poolname,char * ostname)535 int lov_pool_add(struct obd_device *obd, char *poolname, char *ostname)
536 {
537 	struct obd_uuid ost_uuid;
538 	struct lov_obd *lov;
539 	struct pool_desc *pool;
540 	unsigned int lov_idx;
541 	int rc;
542 
543 	lov = &(obd->u.lov);
544 
545 	pool = cfs_hash_lookup(lov->lov_pools_hash_body, poolname);
546 	if (pool == NULL)
547 		return -ENOENT;
548 
549 	obd_str2uuid(&ost_uuid, ostname);
550 
551 
552 	/* search ost in lov array */
553 	obd_getref(obd);
554 	for (lov_idx = 0; lov_idx < lov->desc.ld_tgt_count; lov_idx++) {
555 		if (!lov->lov_tgts[lov_idx])
556 			continue;
557 		if (obd_uuid_equals(&ost_uuid,
558 				    &(lov->lov_tgts[lov_idx]->ltd_uuid)))
559 			break;
560 	}
561 	/* test if ost found in lov */
562 	if (lov_idx == lov->desc.ld_tgt_count) {
563 		rc = -EINVAL;
564 		goto out;
565 	}
566 
567 	rc = lov_ost_pool_add(&pool->pool_obds, lov_idx, lov->lov_tgt_size);
568 	if (rc)
569 		goto out;
570 
571 	pool->pool_rr.lqr_dirty = 1;
572 
573 	CDEBUG(D_CONFIG, "Added %s to "LOV_POOLNAMEF" as member %d\n",
574 	       ostname, poolname,  pool_tgt_count(pool));
575 
576 out:
577 	obd_putref(obd);
578 	lov_pool_putref(pool);
579 	return rc;
580 }
581 
lov_pool_remove(struct obd_device * obd,char * poolname,char * ostname)582 int lov_pool_remove(struct obd_device *obd, char *poolname, char *ostname)
583 {
584 	struct obd_uuid ost_uuid;
585 	struct lov_obd *lov;
586 	struct pool_desc *pool;
587 	unsigned int lov_idx;
588 	int rc = 0;
589 
590 	lov = &(obd->u.lov);
591 
592 	pool = cfs_hash_lookup(lov->lov_pools_hash_body, poolname);
593 	if (pool == NULL)
594 		return -ENOENT;
595 
596 	obd_str2uuid(&ost_uuid, ostname);
597 
598 	obd_getref(obd);
599 	/* search ost in lov array, to get index */
600 	for (lov_idx = 0; lov_idx < lov->desc.ld_tgt_count; lov_idx++) {
601 		if (!lov->lov_tgts[lov_idx])
602 			continue;
603 
604 		if (obd_uuid_equals(&ost_uuid,
605 				    &(lov->lov_tgts[lov_idx]->ltd_uuid)))
606 			break;
607 	}
608 
609 	/* test if ost found in lov */
610 	if (lov_idx == lov->desc.ld_tgt_count) {
611 		rc = -EINVAL;
612 		goto out;
613 	}
614 
615 	lov_ost_pool_remove(&pool->pool_obds, lov_idx);
616 
617 	pool->pool_rr.lqr_dirty = 1;
618 
619 	CDEBUG(D_CONFIG, "%s removed from "LOV_POOLNAMEF"\n", ostname,
620 	       poolname);
621 
622 out:
623 	obd_putref(obd);
624 	lov_pool_putref(pool);
625 	return rc;
626 }
627 
lov_check_index_in_pool(__u32 idx,struct pool_desc * pool)628 int lov_check_index_in_pool(__u32 idx, struct pool_desc *pool)
629 {
630 	int i, rc;
631 
632 	/* caller may no have a ref on pool if it got the pool
633 	 * without calling lov_find_pool() (e.g. go through the lov pool
634 	 * list)
635 	 */
636 	lov_pool_getref(pool);
637 
638 	down_read(&pool_tgt_rw_sem(pool));
639 
640 	for (i = 0; i < pool_tgt_count(pool); i++) {
641 		if (pool_tgt_array(pool)[i] == idx) {
642 			rc = 0;
643 			goto out;
644 		}
645 	}
646 	rc = -ENOENT;
647 out:
648 	up_read(&pool_tgt_rw_sem(pool));
649 
650 	lov_pool_putref(pool);
651 	return rc;
652 }
653 
lov_find_pool(struct lov_obd * lov,char * poolname)654 struct pool_desc *lov_find_pool(struct lov_obd *lov, char *poolname)
655 {
656 	struct pool_desc *pool;
657 
658 	pool = NULL;
659 	if (poolname[0] != '\0') {
660 		pool = cfs_hash_lookup(lov->lov_pools_hash_body, poolname);
661 		if (pool == NULL)
662 			CWARN("Request for an unknown pool ("LOV_POOLNAMEF")\n",
663 			      poolname);
664 		if ((pool != NULL) && (pool_tgt_count(pool) == 0)) {
665 			CWARN("Request for an empty pool ("LOV_POOLNAMEF")\n",
666 			       poolname);
667 			/* pool is ignored, so we remove ref on it */
668 			lov_pool_putref(pool);
669 			pool = NULL;
670 		}
671 	}
672 	return pool;
673 }
674