4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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.
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).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved
24 * Use is subject to license terms.
26 * Copyright (c) 2012, 2017, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
30 * Lustre is a trademark of Sun Microsystems, Inc.
33 * lustre/lod/lod_pool.c
37 * This file provides code related to the Logical Object Device (LOD)
38 * handling of OST Pools on the MDT. Pools are named lists of targets
39 * that allow userspace to group targets that share a particlar property
40 * together so that users or kernel helpers can make decisions about file
41 * allocation based on these properties. For example, pools could be
42 * defined based on fault domains (e.g. separate racks of server nodes) so
43 * that RAID-1 mirroring could select targets from independent fault
44 * domains, or pools could define target performance characteristics so
45 * that applicatins could select IOP-optimized storage or stream-optimized
46 * storage for a particular output file.
48 * This file handles creation, lookup, and removal of pools themselves, as
49 * well as adding and removing targets to pools. It also handles lprocfs
50 * display of configured pool. The pools are accessed by name in the pool
51 * hash, and are refcounted to ensure proper pool structure lifetimes.
53 * Author: Jacques-Charles LAFOUCRIERE <jc.lafoucriere@cea.fr>
54 * Author: Alex Lyashkov <Alexey.Lyashkov@Sun.COM>
55 * Author: Nathaniel Rutman <Nathan.Rutman@Sun.COM>
58 #define DEBUG_SUBSYSTEM S_LOV
60 #include <libcfs/libcfs.h>
61 #include <libcfs/linux/linux-hash.h>
63 #include "lod_internal.h"
65 #define pool_tgt(_p, _i) OST_TGT(lu2lod_dev((_p)->pool_lobd->obd_lu_dev), \
66 (_p)->pool_obds.op_array[_i])
69 * Get a reference on the specified pool.
71 * To ensure the pool descriptor is not freed before the caller is finished
72 * with it. Any process that is accessing \a pool directly needs to hold
73 * reference on it, including /proc since a userspace thread may be holding
74 * the /proc file open and busy in the kernel.
76 * \param[in] pool pool descriptor on which to gain reference
78 static void pool_getref(struct pool_desc *pool)
80 CDEBUG(D_INFO, "pool %p\n", pool);
81 atomic_inc(&pool->pool_refcount);
85 * Drop a reference on the specified pool and free its memory if needed.
87 * One reference is held by the LOD OBD device while it is configured, from
88 * the time the configuration log defines the pool until the time when it is
89 * dropped when the LOD OBD is cleaned up or the pool is deleted. This means
90 * that the pool will not be freed while the LOD device is configured, unless
91 * it is explicitly destroyed by the sysadmin. The pool structure is freed
92 * after the last reference on the structure is released.
94 * \param[in] pool pool descriptor to drop reference on and possibly free
96 void lod_pool_putref(struct pool_desc *pool)
98 CDEBUG(D_INFO, "pool %p\n", pool);
99 if (atomic_dec_and_test(&pool->pool_refcount)) {
100 LASSERT(list_empty(&pool->pool_list));
101 LASSERT(pool->pool_proc_entry == NULL);
102 lod_tgt_pool_free(&(pool->pool_rr.lqr_pool));
103 lod_tgt_pool_free(&(pool->pool_obds));
104 kfree_rcu(pool, pool_rcu);
109 static u32 pool_hashfh(const void *data, u32 len, u32 seed)
111 const char *pool_name = data;
113 return hashlen_hash(cfs_hashlen_string((void *)(unsigned long)seed,
117 static int pool_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
119 const struct pool_desc *pool = obj;
120 const char *pool_name = arg->key;
122 return strcmp(pool_name, pool->pool_name);
125 static const struct rhashtable_params pools_hash_params = {
126 .key_len = 1, /* actually variable */
127 .key_offset = offsetof(struct pool_desc, pool_name),
128 .head_offset = offsetof(struct pool_desc, pool_hash),
129 .hashfn = pool_hashfh,
130 .obj_cmpfn = pool_cmpfn,
131 .automatic_shrinking = true,
135 * Methods for /proc seq_file iteration of the defined pools.
138 #define POOL_IT_MAGIC 0xB001CEA0
139 struct lod_pool_iterator {
140 unsigned int lpi_magic; /* POOL_IT_MAGIC */
141 unsigned int lpi_idx; /* from 0 to pool_tgt_size - 1 */
142 struct pool_desc *lpi_pool;
146 * Return the next configured target within one pool for seq_file iteration.
148 * Iterator is used to go through the target entries of a single pool
149 * (i.e. the list of OSTs configured for a named pool).
150 * lpi_idx is the current target index in the pool's op_array[].
152 * The return type is a void * because this function is one of the
153 * struct seq_operations methods and must match the function template.
155 * \param[in] seq /proc sequence file iteration tracking structure
156 * \param[in] v unused
157 * \param[in] pos position within iteration; 0 to number of targets - 1
159 * \retval struct pool_iterator of the next pool descriptor
161 static void *pool_proc_next(struct seq_file *seq, void *v, loff_t *pos)
163 struct lod_pool_iterator *iter = seq->private;
166 LASSERTF(iter->lpi_magic == POOL_IT_MAGIC, "%08X\n", iter->lpi_magic);
168 /* test if end of file */
169 if (*pos >= pool_tgt_count(iter->lpi_pool))
172 OBD_FAIL_TIMEOUT(OBD_FAIL_OST_LIST_ASSERT, cfs_fail_val);
174 /* iterate to find a non empty entry */
175 prev_idx = iter->lpi_idx;
177 if (iter->lpi_idx >= pool_tgt_count(iter->lpi_pool)) {
178 iter->lpi_idx = prev_idx; /* we stay on the last entry */
182 /* return != NULL to continue */
187 * Start seq_file iteration via /proc for a single pool.
189 * The \a pos parameter may be non-zero, indicating that the iteration
190 * is starting at some offset in the target list. Use the seq_file
191 * private field to memorize the iterator so we can free it at stop().
192 * Need to restore the private pointer to the pool before freeing it.
194 * \param[in] seq new sequence file structure to initialize
195 * \param[in] pos initial target number at which to start iteration
197 * \retval initialized pool iterator private structure
198 * \retval NULL if \a pos exceeds the number of targets in \a pool
199 * \retval negative error number on failure
201 static void *pool_proc_start(struct seq_file *seq, loff_t *pos)
203 struct pool_desc *pool = seq->private;
204 struct lod_pool_iterator *iter;
207 if ((pool_tgt_count(pool) == 0) ||
208 (*pos >= pool_tgt_count(pool))) {
209 /* iter is not created, so stop() has no way to
210 * find pool to dec ref */
211 lod_pool_putref(pool);
217 return ERR_PTR(-ENOMEM);
218 iter->lpi_magic = POOL_IT_MAGIC;
219 iter->lpi_pool = pool;
223 down_read(&pool_tgt_rw_sem(pool));
230 ptr = pool_proc_next(seq, &iter, &i);
231 } while ((i < *pos) && (ptr != NULL));
240 * Finish seq_file iteration for a single pool.
242 * Once iteration has been completed, the pool_iterator struct must be
243 * freed, and the seq_file private pointer restored to the pool, as it
244 * was initially when pool_proc_start() was called.
246 * In some cases the stop() method may be called 2 times, without calling
247 * the start() method (see seq_read() from fs/seq_file.c). We have to free
248 * the private iterator struct only if seq->private points to the iterator.
250 * \param[in] seq sequence file structure to clean up
251 * \param[in] v (unused)
253 static void pool_proc_stop(struct seq_file *seq, void *v)
255 struct lod_pool_iterator *iter = seq->private;
257 if (iter != NULL && iter->lpi_magic == POOL_IT_MAGIC) {
258 up_read(&pool_tgt_rw_sem(iter->lpi_pool));
259 seq->private = iter->lpi_pool;
260 lod_pool_putref(iter->lpi_pool);
266 * Print out one target entry from the pool for seq_file iteration.
268 * The currently referenced pool target is given by op_array[lpi_idx].
270 * \param[in] seq new sequence file structure to initialize
271 * \param[in] v (unused)
273 static int pool_proc_show(struct seq_file *seq, void *v)
275 struct lod_pool_iterator *iter = v;
276 struct lod_tgt_desc *tgt;
278 LASSERTF(iter->lpi_magic == POOL_IT_MAGIC, "%08X\n", iter->lpi_magic);
279 LASSERT(iter->lpi_pool != NULL);
280 LASSERT(iter->lpi_idx <= pool_tgt_count(iter->lpi_pool));
282 tgt = pool_tgt(iter->lpi_pool, iter->lpi_idx);
284 seq_printf(seq, "%s\n", obd_uuid2str(&(tgt->ltd_uuid)));
289 static const struct seq_operations pool_proc_ops = {
290 .start = pool_proc_start,
291 .next = pool_proc_next,
292 .stop = pool_proc_stop,
293 .show = pool_proc_show,
297 * Open a new /proc file for seq_file iteration of targets in one pool.
299 * Initialize the seq_file private pointer to reference the pool.
301 * \param inode inode to store iteration state for /proc
302 * \param file file descriptor to store iteration methods
304 * \retval 0 for success
305 * \retval negative error number on failure
307 static int pool_proc_open(struct inode *inode, struct file *file)
311 rc = seq_open(file, &pool_proc_ops);
313 struct seq_file *seq = file->private_data;
314 seq->private = PDE_DATA(inode);
319 static struct file_operations pool_proc_operations = {
320 .open = pool_proc_open,
323 .release = seq_release,
327 * Dump the pool target list into the Lustre debug log.
329 * This is a debugging function to allow dumping the list of targets
330 * in \a pool to the Lustre kernel debug log at the given \a level.
332 * This is not currently called by any existing code, but can be called
333 * from within gdb/crash to display the contents of the pool, or from
334 * code under development.
336 * \param[in] level Lustre debug level (D_INFO, D_WARN, D_ERROR, etc)
337 * \param[in] pool pool descriptor to be dumped
339 void lod_dump_pool(int level, struct pool_desc *pool)
345 CDEBUG(level, "pool "LOV_POOLNAMEF" has %d members\n",
346 pool->pool_name, pool->pool_obds.op_count);
347 down_read(&pool_tgt_rw_sem(pool));
349 for (i = 0; i < pool_tgt_count(pool) ; i++) {
350 if (!pool_tgt(pool, i) || !(pool_tgt(pool, i))->ltd_exp)
352 CDEBUG(level, "pool "LOV_POOLNAMEF"[%d] = %s\n",
354 obd_uuid2str(&((pool_tgt(pool, i))->ltd_uuid)));
357 up_read(&pool_tgt_rw_sem(pool));
358 lod_pool_putref(pool);
362 * Initialize the pool data structures at startup.
364 * Allocate and initialize the pool data structures with the specified
365 * array size. If pool count is not specified (\a count == 0), then
366 * POOL_INIT_COUNT will be used. Allocating a non-zero initial array
367 * size avoids the need to reallocate as new pools are added.
369 * \param[in] op pool structure
370 * \param[in] count initial size of the target op_array[] array
372 * \retval 0 indicates successful pool initialization
373 * \retval negative error number on failure
375 #define POOL_INIT_COUNT 2
376 int lod_tgt_pool_init(struct lu_tgt_pool *op, unsigned int count)
381 count = POOL_INIT_COUNT;
384 init_rwsem(&op->op_rw_sem);
385 op->op_size = count * sizeof(op->op_array[0]);
386 OBD_ALLOC(op->op_array, op->op_size);
387 if (op->op_array == NULL) {
396 * Increase the op_array size to hold more targets in this pool.
398 * The size is increased to at least \a min_count, but may be larger
399 * for an existing pool since ->op_array[] is growing exponentially.
400 * Caller must hold write op_rwlock.
402 * \param[in] op pool structure
403 * \param[in] min_count minimum number of entries to handle
405 * \retval 0 on success
406 * \retval negative error number on failure.
408 int lod_tgt_pool_extend(struct lu_tgt_pool *op, unsigned int min_count)
413 LASSERT(min_count != 0);
415 if (op->op_count * sizeof(op->op_array[0]) < op->op_size)
418 new_size = max_t(__u32, min_count * sizeof(op->op_array[0]),
420 OBD_ALLOC(new, new_size);
424 /* copy old array to new one */
425 memcpy(new, op->op_array, op->op_size);
426 OBD_FREE(op->op_array, op->op_size);
428 op->op_size = new_size;
434 * Add a new target to an existing pool.
436 * Add a new target device to the pool previously created and returned by
437 * lod_pool_new(). Each target can only be in each pool at most one time.
439 * \param[in] op target pool to add new entry
440 * \param[in] idx pool index number to add to the \a op array
441 * \param[in] min_count minimum number of entries to expect in the pool
443 * \retval 0 if target could be added to the pool
444 * \retval negative error if target \a idx was not added
446 int lod_tgt_pool_add(struct lu_tgt_pool *op, __u32 idx, unsigned int min_count)
452 down_write(&op->op_rw_sem);
454 rc = lod_tgt_pool_extend(op, min_count);
458 /* search ost in pool array */
459 for (i = 0; i < op->op_count; i++) {
460 if (op->op_array[i] == idx)
461 GOTO(out, rc = -EEXIST);
463 /* ost not found we add it */
464 op->op_array[op->op_count] = idx;
468 up_write(&op->op_rw_sem);
473 * Remove an existing pool from the system.
475 * The specified pool must have previously been allocated by
476 * lod_pool_new() and not have any target members in the pool.
477 * If the removed target is not the last, compact the array
478 * to remove empty spaces.
480 * \param[in] op pointer to the original data structure
481 * \param[in] idx target index to be removed
483 * \retval 0 on success
484 * \retval negative error number on failure
486 int lod_tgt_pool_remove(struct lu_tgt_pool *op, __u32 idx)
491 down_write(&op->op_rw_sem);
493 for (i = 0; i < op->op_count; i++) {
494 if (op->op_array[i] == idx) {
495 memmove(&op->op_array[i], &op->op_array[i + 1],
496 (op->op_count - i - 1) *
497 sizeof(op->op_array[0]));
499 up_write(&op->op_rw_sem);
505 up_write(&op->op_rw_sem);
510 * Free the pool after it was emptied and removed from /proc.
512 * Note that all of the child/target entries referenced by this pool
513 * must have been removed by lod_ost_pool_remove() before it can be
514 * deleted from memory.
516 * \param[in] op pool to be freed.
518 * \retval 0 on success or if pool was already freed
520 int lod_tgt_pool_free(struct lu_tgt_pool *op)
524 if (op->op_size == 0)
527 down_write(&op->op_rw_sem);
529 OBD_FREE(op->op_array, op->op_size);
534 up_write(&op->op_rw_sem);
538 static void pools_hash_exit(void *vpool, void *data)
540 struct pool_desc *pool = vpool;
542 lod_pool_putref(pool);
545 int lod_pool_hash_init(struct rhashtable *tbl)
547 return rhashtable_init(tbl, &pools_hash_params);
550 void lod_pool_hash_destroy(struct rhashtable *tbl)
552 rhashtable_free_and_destroy(tbl, pools_hash_exit, NULL);
556 * Allocate a new pool for the specified device.
558 * Allocate a new pool_desc structure for the specified \a new_pool
559 * device to create a pool with the given \a poolname. The new pool
560 * structure is created with a single reference, and is freed when the
561 * reference count drops to zero.
563 * \param[in] obd Lustre OBD device on which to add a pool iterator
564 * \param[in] poolname the name of the pool to be created
566 * \retval 0 in case of success
567 * \retval negative error code in case of error
569 int lod_pool_new(struct obd_device *obd, char *poolname)
571 struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev);
572 struct pool_desc *new_pool;
576 if (strlen(poolname) > LOV_MAXPOOLNAME)
577 RETURN(-ENAMETOOLONG);
579 /* OBD_ALLOC_* doesn't work with direct kfree_rcu use */
580 new_pool = kmalloc(sizeof(*new_pool), GFP_KERNEL);
581 if (new_pool == NULL)
584 strlcpy(new_pool->pool_name, poolname, sizeof(new_pool->pool_name));
585 new_pool->pool_lobd = obd;
586 atomic_set(&new_pool->pool_refcount, 1);
587 rc = lod_tgt_pool_init(&new_pool->pool_obds, 0);
591 lu_qos_rr_init(&new_pool->pool_rr);
593 rc = lod_tgt_pool_init(&new_pool->pool_rr.lqr_pool, 0);
595 GOTO(out_free_pool_obds, rc);
597 #ifdef CONFIG_PROC_FS
598 pool_getref(new_pool);
599 new_pool->pool_proc_entry = lprocfs_add_simple(lod->lod_pool_proc_entry,
601 &pool_proc_operations);
602 if (IS_ERR(new_pool->pool_proc_entry)) {
603 CDEBUG(D_CONFIG, "%s: cannot add proc entry "LOV_POOLNAMEF"\n",
604 obd->obd_name, poolname);
605 new_pool->pool_proc_entry = NULL;
606 lod_pool_putref(new_pool);
608 CDEBUG(D_INFO, "pool %p - proc %p\n", new_pool,
609 new_pool->pool_proc_entry);
612 spin_lock(&obd->obd_dev_lock);
613 list_add_tail(&new_pool->pool_list, &lod->lod_pool_list);
614 lod->lod_pool_count++;
615 spin_unlock(&obd->obd_dev_lock);
617 /* Add to hash table only when it is fully ready. */
618 rc = rhashtable_lookup_insert_fast(&lod->lod_pools_hash_body,
619 &new_pool->pool_hash,
624 * Hide -E2BIG and -EBUSY which
631 CDEBUG(D_CONFIG, LOV_POOLNAMEF" is pool #%d\n",
632 poolname, lod->lod_pool_count);
637 spin_lock(&obd->obd_dev_lock);
638 list_del_init(&new_pool->pool_list);
639 lod->lod_pool_count--;
640 spin_unlock(&obd->obd_dev_lock);
642 lprocfs_remove(&new_pool->pool_proc_entry);
644 lod_tgt_pool_free(&new_pool->pool_rr.lqr_pool);
646 lod_tgt_pool_free(&new_pool->pool_obds);
647 OBD_FREE_PTR(new_pool);
652 * Remove the named pool from the OBD device.
654 * \param[in] obd OBD device on which pool was previously created
655 * \param[in] poolname name of pool to remove from \a obd
657 * \retval 0 on successfully removing the pool
658 * \retval negative error numbers for failures
660 int lod_pool_del(struct obd_device *obd, char *poolname)
662 struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev);
663 struct pool_desc *pool;
666 /* lookup and kill hash reference */
668 pool = rhashtable_lookup(&lod->lod_pools_hash_body, poolname,
670 if (pool && rhashtable_remove_fast(&lod->lod_pools_hash_body,
672 pools_hash_params) != 0)
678 if (pool->pool_proc_entry != NULL) {
679 CDEBUG(D_INFO, "proc entry %p\n", pool->pool_proc_entry);
680 lprocfs_remove(&pool->pool_proc_entry);
681 lod_pool_putref(pool);
684 spin_lock(&obd->obd_dev_lock);
685 list_del_init(&pool->pool_list);
686 lod->lod_pool_count--;
687 spin_unlock(&obd->obd_dev_lock);
689 /* release last reference */
690 lod_pool_putref(pool);
696 * Add a single target device to the named pool.
698 * Add the target specified by \a ostname to the specified \a poolname.
700 * \param[in] obd OBD device on which to add the pool
701 * \param[in] poolname name of the pool to which to add the target \a ostname
702 * \param[in] ostname name of the target device to be added
704 * \retval 0 if \a ostname was (previously) added to the named pool
705 * \retval negative error number on failure
707 int lod_pool_add(struct obd_device *obd, char *poolname, char *ostname)
709 struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev);
710 struct obd_uuid ost_uuid;
711 struct pool_desc *pool;
712 struct lu_tgt_desc *tgt;
717 pool = rhashtable_lookup(&lod->lod_pools_hash_body, poolname,
719 if (pool && !atomic_inc_not_zero(&pool->pool_refcount))
725 obd_str2uuid(&ost_uuid, ostname);
727 /* search ost in lod array */
728 lod_getref(&lod->lod_ost_descs);
729 lod_foreach_ost(lod, tgt) {
730 if (obd_uuid_equals(&ost_uuid, &tgt->ltd_uuid)) {
739 rc = lod_tgt_pool_add(&pool->pool_obds, tgt->ltd_index,
744 pool->pool_rr.lqr_dirty = 1;
746 CDEBUG(D_CONFIG, "Added %s to "LOV_POOLNAMEF" as member %d\n",
747 ostname, poolname, pool_tgt_count(pool));
751 lod_putref(lod, &lod->lod_ost_descs);
752 lod_pool_putref(pool);
757 * Remove the named target from the specified pool.
759 * Remove one target named \a ostname from \a poolname. The \a ostname
760 * is searched for in the lod_device lod_ost_bitmap array, to ensure the
761 * specified name actually exists in the pool.
763 * \param[in] obd OBD device from which to remove \a poolname
764 * \param[in] poolname name of the pool to be changed
765 * \param[in] ostname name of the target to remove from \a poolname
767 * \retval 0 on successfully removing \a ostname from the pool
768 * \retval negative number on error (e.g. \a ostname not in pool)
770 int lod_pool_remove(struct obd_device *obd, char *poolname, char *ostname)
772 struct lod_device *lod = lu2lod_dev(obd->obd_lu_dev);
773 struct lu_tgt_desc *ost;
774 struct obd_uuid ost_uuid;
775 struct pool_desc *pool;
779 /* lookup and kill hash reference */
781 pool = rhashtable_lookup(&lod->lod_pools_hash_body, poolname,
783 if (pool && !atomic_inc_not_zero(&pool->pool_refcount))
789 obd_str2uuid(&ost_uuid, ostname);
791 lod_getref(&lod->lod_ost_descs);
792 lod_foreach_ost(lod, ost) {
793 if (obd_uuid_equals(&ost_uuid, &ost->ltd_uuid)) {
799 /* test if ost found in lod array */
803 lod_tgt_pool_remove(&pool->pool_obds, ost->ltd_index);
804 pool->pool_rr.lqr_dirty = 1;
806 CDEBUG(D_CONFIG, "%s removed from "LOV_POOLNAMEF"\n", ostname,
811 lod_putref(lod, &lod->lod_ost_descs);
812 lod_pool_putref(pool);
817 * Check if the specified target exists in the pool.
819 * The caller may not have a reference on \a pool if it got the pool without
820 * calling lod_find_pool() (e.g. directly from the lod pool list)
822 * \param[in] idx Target index to check
823 * \param[in] pool Pool in which to check if target is added.
825 * \retval 0 successfully found index in \a pool
826 * \retval negative error if device not found in \a pool
828 int lod_check_index_in_pool(__u32 idx, struct pool_desc *pool)
836 down_read(&pool_tgt_rw_sem(pool));
838 for (i = 0; i < pool_tgt_count(pool); i++) {
839 if (pool_tgt_array(pool)[i] == idx)
845 up_read(&pool_tgt_rw_sem(pool));
847 lod_pool_putref(pool);
852 * Find the pool descriptor for the specified pool and return it with a
853 * reference to the caller if found.
855 * \param[in] lod LOD on which the pools are configured
856 * \param[in] poolname NUL-terminated name of the pool
858 * \retval pointer to pool descriptor on success
859 * \retval NULL if \a poolname could not be found or poolname is empty
861 struct pool_desc *lod_find_pool(struct lod_device *lod, char *poolname)
863 struct pool_desc *pool;
866 if (poolname[0] != '\0') {
868 pool = rhashtable_lookup(&lod->lod_pools_hash_body, poolname,
870 if (pool && !atomic_inc_not_zero(&pool->pool_refcount))
875 "%s: request for an unknown pool (" LOV_POOLNAMEF ")\n",
876 lod->lod_child_exp->exp_obd->obd_name, poolname);
877 if (pool != NULL && pool_tgt_count(pool) == 0) {
878 CDEBUG(D_CONFIG, "%s: request for an empty pool ("
880 lod->lod_child_exp->exp_obd->obd_name, poolname);
881 /* pool is ignored, so we remove ref on it */
882 lod_pool_putref(pool);