text: /*
   * GPL HEADER START
   *
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 only,
   * as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License version 2 for more details (a copy is included
   * in the LICENSE file that accompanied this code).
   *
   * You should have received a copy of the GNU General Public License
   * version 2 along with this program; If not, see
   * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
   *
   * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
   * CA 95054 USA or visit www.sun.com if you need additional information or
   * have any questions.
   *
   * GPL HEADER END
   */
  /*
   * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
   * Use is subject to license terms.
   *
   * Copyright (c) 2010, 2012, Intel Corporation.
   */
  /*
   * This file is part of Lustre, http://www.lustre.org/
   * Lustre is a trademark of Sun Microsystems, Inc.
   *
   * lustre/ldlm/ldlm_resource.c
   *
   * Author: Phil Schwan <phil@clusterfs.com>
   * Author: Peter Braam <braam@clusterfs.com>
   */
  
  #define DEBUG_SUBSYSTEM S_LDLM
  #include "../include/lustre_dlm.h"
  #include "../include/lustre_fid.h"
  #include "../include/obd_class.h"
  #include "ldlm_internal.h"
  
  struct kmem_cache *ldlm_resource_slab, *ldlm_lock_slab;
  
  int ldlm_srv_namespace_nr = 0;
  int ldlm_cli_namespace_nr = 0;
  
  struct mutex ldlm_srv_namespace_lock;
  LIST_HEAD(ldlm_srv_namespace_list);
  
  struct mutex ldlm_cli_namespace_lock;
  /* Client Namespaces that have active resources in them.
   * Once all resources go away, ldlm_poold moves such namespaces to the
   * inactive list */
  LIST_HEAD(ldlm_cli_active_namespace_list);
  /* Client namespaces that don't have any locks in them */
  LIST_HEAD(ldlm_cli_inactive_namespace_list);
  
  static struct dentry *ldlm_debugfs_dir;
  static struct dentry *ldlm_ns_debugfs_dir;
  struct dentry *ldlm_svc_debugfs_dir;
  
  /* during debug dump certain amount of granted locks for one resource to avoid
   * DDOS. */
  unsigned int ldlm_dump_granted_max = 256;
  
  static ssize_t
  lprocfs_wr_dump_ns(struct file *file, const char __user *buffer,
  		   size_t count, loff_t *off)
  {
  	ldlm_dump_all_namespaces(LDLM_NAMESPACE_SERVER, D_DLMTRACE);
  	ldlm_dump_all_namespaces(LDLM_NAMESPACE_CLIENT, D_DLMTRACE);
  	return count;
  }
  LPROC_SEQ_FOPS_WR_ONLY(ldlm, dump_ns);
  
  LPROC_SEQ_FOPS_RW_TYPE(ldlm_rw, uint);
  
  static struct lprocfs_vars ldlm_debugfs_list[] = {
  	{ "dump_namespaces", &ldlm_dump_ns_fops, NULL, 0222 },
  	{ "dump_granted_max", &ldlm_rw_uint_fops, &ldlm_dump_granted_max },
  	{ NULL }
  };
  
  int ldlm_debugfs_setup(void)
  {
  	int rc;
  
  	ldlm_debugfs_dir = ldebugfs_register(OBD_LDLM_DEVICENAME,
  					     debugfs_lustre_root,
  					     NULL, NULL);
  	if (IS_ERR_OR_NULL(ldlm_debugfs_dir)) {
  		CERROR("LProcFS failed in ldlm-init\n");
  		rc = ldlm_debugfs_dir ? PTR_ERR(ldlm_debugfs_dir) : -ENOMEM;
  		goto err;
  	}
  
  	ldlm_ns_debugfs_dir = ldebugfs_register("namespaces",
  						ldlm_debugfs_dir,
  						NULL, NULL);
  	if (IS_ERR_OR_NULL(ldlm_ns_debugfs_dir)) {
  		CERROR("LProcFS failed in ldlm-init\n");
  		rc = ldlm_ns_debugfs_dir ? PTR_ERR(ldlm_ns_debugfs_dir)
  					 : -ENOMEM;
  		goto err_type;
  	}
  
  	ldlm_svc_debugfs_dir = ldebugfs_register("services",
  						 ldlm_debugfs_dir,
  						 NULL, NULL);
  	if (IS_ERR_OR_NULL(ldlm_svc_debugfs_dir)) {
  		CERROR("LProcFS failed in ldlm-init\n");
  		rc = ldlm_svc_debugfs_dir ? PTR_ERR(ldlm_svc_debugfs_dir)
  					  : -ENOMEM;
  		goto err_ns;
  	}
  
  	rc = ldebugfs_add_vars(ldlm_debugfs_dir, ldlm_debugfs_list, NULL);
  
  	return 0;
  
  err_ns:
  	ldebugfs_remove(&ldlm_ns_debugfs_dir);
  err_type:
  	ldebugfs_remove(&ldlm_debugfs_dir);
  err:
  	ldlm_svc_debugfs_dir = NULL;
  	ldlm_ns_debugfs_dir = NULL;
  	ldlm_debugfs_dir = NULL;
  	return rc;
  }
  
  void ldlm_debugfs_cleanup(void)
  {
  	if (!IS_ERR_OR_NULL(ldlm_svc_debugfs_dir))
  		ldebugfs_remove(&ldlm_svc_debugfs_dir);
  
  	if (!IS_ERR_OR_NULL(ldlm_ns_debugfs_dir))
  		ldebugfs_remove(&ldlm_ns_debugfs_dir);
  
  	if (!IS_ERR_OR_NULL(ldlm_debugfs_dir))
  		ldebugfs_remove(&ldlm_debugfs_dir);
  
  	ldlm_svc_debugfs_dir = NULL;
  	ldlm_ns_debugfs_dir = NULL;
  	ldlm_debugfs_dir = NULL;
  }
  
  static ssize_t resource_count_show(struct kobject *kobj, struct attribute *attr,
  				   char *buf)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	__u64		  res = 0;
  	struct cfs_hash_bd	  bd;
  	int		    i;
  
  	/* result is not strictly consistent */
  	cfs_hash_for_each_bucket(ns->ns_rs_hash, &bd, i)
  		res += cfs_hash_bd_count_get(&bd);
  	return sprintf(buf, "%lld\n", res);
  }
  LUSTRE_RO_ATTR(resource_count);
  
  static ssize_t lock_count_show(struct kobject *kobj, struct attribute *attr,
  			       char *buf)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	__u64		  locks;
  
  	locks = lprocfs_stats_collector(ns->ns_stats, LDLM_NSS_LOCKS,
  					LPROCFS_FIELDS_FLAGS_SUM);
  	return sprintf(buf, "%lld\n", locks);
  }
  LUSTRE_RO_ATTR(lock_count);
  
  static ssize_t lock_unused_count_show(struct kobject *kobj,
  				      struct attribute *attr,
  				      char *buf)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  
  	return sprintf(buf, "%d\n", ns->ns_nr_unused);
  }
  LUSTRE_RO_ATTR(lock_unused_count);
  
  static ssize_t lru_size_show(struct kobject *kobj, struct attribute *attr,
  			     char *buf)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	__u32 *nr = &ns->ns_max_unused;
  
  	if (ns_connect_lru_resize(ns))
  		nr = &ns->ns_nr_unused;
  	return sprintf(buf, "%u", *nr);
  }
  
  static ssize_t lru_size_store(struct kobject *kobj, struct attribute *attr,
  			      const char *buffer, size_t count)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	unsigned long tmp;
  	int lru_resize;
  	int err;
  
  	if (strncmp(buffer, "clear", 5) == 0) {
  		CDEBUG(D_DLMTRACE,
  		       "dropping all unused locks from namespace %s\n",
  		       ldlm_ns_name(ns));
  		if (ns_connect_lru_resize(ns)) {
  			int canceled, unused  = ns->ns_nr_unused;
  
  			/* Try to cancel all @ns_nr_unused locks. */
  			canceled = ldlm_cancel_lru(ns, unused, 0,
  						   LDLM_CANCEL_PASSED);
  			if (canceled < unused) {
  				CDEBUG(D_DLMTRACE,
  				       "not all requested locks are canceled, requested: %d, canceled: %d\n",
  				       unused,
  				       canceled);
  				return -EINVAL;
  			}
  		} else {
  			tmp = ns->ns_max_unused;
  			ns->ns_max_unused = 0;
  			ldlm_cancel_lru(ns, 0, 0, LDLM_CANCEL_PASSED);
  			ns->ns_max_unused = tmp;
  		}
  		return count;
  	}
  
  	err = kstrtoul(buffer, 10, &tmp);
  	if (err != 0) {
  		CERROR("lru_size: invalid value written\n");
  		return -EINVAL;
  	}
  	lru_resize = (tmp == 0);
  
  	if (ns_connect_lru_resize(ns)) {
  		if (!lru_resize)
  			ns->ns_max_unused = (unsigned int)tmp;
  
  		if (tmp > ns->ns_nr_unused)
  			tmp = ns->ns_nr_unused;
  		tmp = ns->ns_nr_unused - tmp;
  
  		CDEBUG(D_DLMTRACE,
  		       "changing namespace %s unused locks from %u to %u\n",
  		       ldlm_ns_name(ns), ns->ns_nr_unused,
  		       (unsigned int)tmp);
  		ldlm_cancel_lru(ns, tmp, LCF_ASYNC, LDLM_CANCEL_PASSED);
  
  		if (!lru_resize) {
  			CDEBUG(D_DLMTRACE,
  			       "disable lru_resize for namespace %s\n",
  			       ldlm_ns_name(ns));
  			ns->ns_connect_flags &= ~OBD_CONNECT_LRU_RESIZE;
  		}
  	} else {
  		CDEBUG(D_DLMTRACE,
  		       "changing namespace %s max_unused from %u to %u\n",
  		       ldlm_ns_name(ns), ns->ns_max_unused,
  		       (unsigned int)tmp);
  		ns->ns_max_unused = (unsigned int)tmp;
  		ldlm_cancel_lru(ns, 0, LCF_ASYNC, LDLM_CANCEL_PASSED);
  
  		/* Make sure that LRU resize was originally supported before
  		 * turning it on here. */
  		if (lru_resize &&
  		    (ns->ns_orig_connect_flags & OBD_CONNECT_LRU_RESIZE)) {
  			CDEBUG(D_DLMTRACE,
  			       "enable lru_resize for namespace %s\n",
  			       ldlm_ns_name(ns));
  			ns->ns_connect_flags |= OBD_CONNECT_LRU_RESIZE;
  		}
  	}
  
  	return count;
  }
  LUSTRE_RW_ATTR(lru_size);
  
  static ssize_t lru_max_age_show(struct kobject *kobj, struct attribute *attr,
  				char *buf)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  
  	return sprintf(buf, "%u", ns->ns_max_age);
  }
  
  static ssize_t lru_max_age_store(struct kobject *kobj, struct attribute *attr,
  				 const char *buffer, size_t count)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	unsigned long tmp;
  	int err;
  
  	err = kstrtoul(buffer, 10, &tmp);
  	if (err != 0)
  		return -EINVAL;
  
  	ns->ns_max_age = tmp;
  
  	return count;
  }
  LUSTRE_RW_ATTR(lru_max_age);
  
  static ssize_t early_lock_cancel_show(struct kobject *kobj,
  				      struct attribute *attr,
  				      char *buf)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  
  	return sprintf(buf, "%d\n", ns_connect_cancelset(ns));
  }
  
  static ssize_t early_lock_cancel_store(struct kobject *kobj,
  				       struct attribute *attr,
  				       const char *buffer,
  				       size_t count)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	unsigned long supp = -1;
  	int rc;
  
  	rc = kstrtoul(buffer, 10, &supp);
  	if (rc < 0)
  		return rc;
  
  	if (supp == 0)
  		ns->ns_connect_flags &= ~OBD_CONNECT_CANCELSET;
  	else if (ns->ns_orig_connect_flags & OBD_CONNECT_CANCELSET)
  		ns->ns_connect_flags |= OBD_CONNECT_CANCELSET;
  	return count;
  }
  LUSTRE_RW_ATTR(early_lock_cancel);
  
  /* These are for namespaces in /sys/fs/lustre/ldlm/namespaces/ */
  static struct attribute *ldlm_ns_attrs[] = {
  	&lustre_attr_resource_count.attr,
  	&lustre_attr_lock_count.attr,
  	&lustre_attr_lock_unused_count.attr,
  	&lustre_attr_lru_size.attr,
  	&lustre_attr_lru_max_age.attr,
  	&lustre_attr_early_lock_cancel.attr,
  	NULL,
  };
  
  static void ldlm_ns_release(struct kobject *kobj)
  {
  	struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace,
  						 ns_kobj);
  	complete(&ns->ns_kobj_unregister);
  }
  
  static struct kobj_type ldlm_ns_ktype = {
  	.default_attrs  = ldlm_ns_attrs,
  	.sysfs_ops      = &lustre_sysfs_ops,
  	.release        = ldlm_ns_release,
  };
  
  static void ldlm_namespace_debugfs_unregister(struct ldlm_namespace *ns)
  {
  	if (IS_ERR_OR_NULL(ns->ns_debugfs_entry))
  		CERROR("dlm namespace %s has no procfs dir?\n",
  		       ldlm_ns_name(ns));
  	else
  		ldebugfs_remove(&ns->ns_debugfs_entry);
  
  	if (ns->ns_stats != NULL)
  		lprocfs_free_stats(&ns->ns_stats);
  }
  
  void ldlm_namespace_sysfs_unregister(struct ldlm_namespace *ns)
  {
  	kobject_put(&ns->ns_kobj);
  	wait_for_completion(&ns->ns_kobj_unregister);
  }
  
  int ldlm_namespace_sysfs_register(struct ldlm_namespace *ns)
  {
  	int err;
  
  	ns->ns_kobj.kset = ldlm_ns_kset;
  	init_completion(&ns->ns_kobj_unregister);
  	err = kobject_init_and_add(&ns->ns_kobj, &ldlm_ns_ktype, NULL,
  				   "%s", ldlm_ns_name(ns));
  
  	ns->ns_stats = lprocfs_alloc_stats(LDLM_NSS_LAST, 0);
  	if (ns->ns_stats == NULL) {
  		kobject_put(&ns->ns_kobj);
  		return -ENOMEM;
  	}
  
  	lprocfs_counter_init(ns->ns_stats, LDLM_NSS_LOCKS,
  			     LPROCFS_CNTR_AVGMINMAX, "locks", "locks");
  
  	return err;
  }
  
  static int ldlm_namespace_debugfs_register(struct ldlm_namespace *ns)
  {
  	struct dentry *ns_entry;
  
  	if (!IS_ERR_OR_NULL(ns->ns_debugfs_entry)) {
  		ns_entry = ns->ns_debugfs_entry;
  	} else {
  		ns_entry = debugfs_create_dir(ldlm_ns_name(ns),
  					      ldlm_ns_debugfs_dir);
  		if (ns_entry == NULL)
  			return -ENOMEM;
  		ns->ns_debugfs_entry = ns_entry;
  	}
  
  	return 0;
  }
  #undef MAX_STRING_SIZE
  
  static unsigned ldlm_res_hop_hash(struct cfs_hash *hs,
  				  const void *key, unsigned mask)
  {
  	const struct ldlm_res_id     *id  = key;
  	unsigned		val = 0;
  	unsigned		i;
  
  	for (i = 0; i < RES_NAME_SIZE; i++)
  		val += id->name[i];
  	return val & mask;
  }
  
  static unsigned ldlm_res_hop_fid_hash(struct cfs_hash *hs,
  				      const void *key, unsigned mask)
  {
  	const struct ldlm_res_id *id = key;
  	struct lu_fid       fid;
  	__u32	       hash;
  	__u32	       val;
  
  	fid.f_seq = id->name[LUSTRE_RES_ID_SEQ_OFF];
  	fid.f_oid = (__u32)id->name[LUSTRE_RES_ID_VER_OID_OFF];
  	fid.f_ver = (__u32)(id->name[LUSTRE_RES_ID_VER_OID_OFF] >> 32);
  
  	hash = fid_flatten32(&fid);
  	hash += (hash >> 4) + (hash << 12); /* mixing oid and seq */
  	if (id->name[LUSTRE_RES_ID_HSH_OFF] != 0) {
  		val = id->name[LUSTRE_RES_ID_HSH_OFF];
  		hash += (val >> 5) + (val << 11);
  	} else {
  		val = fid_oid(&fid);
  	}
  	hash = hash_long(hash, hs->hs_bkt_bits);
  	/* give me another random factor */
  	hash -= hash_long((unsigned long)hs, val % 11 + 3);
  
  	hash <<= hs->hs_cur_bits - hs->hs_bkt_bits;
  	hash |= ldlm_res_hop_hash(hs, key, CFS_HASH_NBKT(hs) - 1);
  
  	return hash & mask;
  }
  
  static void *ldlm_res_hop_key(struct hlist_node *hnode)
  {
  	struct ldlm_resource   *res;
  
  	res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  	return &res->lr_name;
  }
  
  static int ldlm_res_hop_keycmp(const void *key, struct hlist_node *hnode)
  {
  	struct ldlm_resource   *res;
  
  	res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  	return ldlm_res_eq((const struct ldlm_res_id *)key,
  			   (const struct ldlm_res_id *)&res->lr_name);
  }
  
  static void *ldlm_res_hop_object(struct hlist_node *hnode)
  {
  	return hlist_entry(hnode, struct ldlm_resource, lr_hash);
  }
  
  static void ldlm_res_hop_get_locked(struct cfs_hash *hs,
  				    struct hlist_node *hnode)
  {
  	struct ldlm_resource *res;
  
  	res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  	ldlm_resource_getref(res);
  }
  
  static void ldlm_res_hop_put_locked(struct cfs_hash *hs,
  				    struct hlist_node *hnode)
  {
  	struct ldlm_resource *res;
  
  	res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  	/* cfs_hash_for_each_nolock is the only chance we call it */
  	ldlm_resource_putref_locked(res);
  }
  
  static void ldlm_res_hop_put(struct cfs_hash *hs, struct hlist_node *hnode)
  {
  	struct ldlm_resource *res;
  
  	res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  	ldlm_resource_putref(res);
  }
  
  cfs_hash_ops_t ldlm_ns_hash_ops = {
  	.hs_hash	= ldlm_res_hop_hash,
  	.hs_key	 = ldlm_res_hop_key,
  	.hs_keycmp      = ldlm_res_hop_keycmp,
  	.hs_keycpy      = NULL,
  	.hs_object      = ldlm_res_hop_object,
  	.hs_get	 = ldlm_res_hop_get_locked,
  	.hs_put_locked  = ldlm_res_hop_put_locked,
  	.hs_put	 = ldlm_res_hop_put
  };
  
  cfs_hash_ops_t ldlm_ns_fid_hash_ops = {
  	.hs_hash	= ldlm_res_hop_fid_hash,
  	.hs_key	 = ldlm_res_hop_key,
  	.hs_keycmp      = ldlm_res_hop_keycmp,
  	.hs_keycpy      = NULL,
  	.hs_object      = ldlm_res_hop_object,
  	.hs_get	 = ldlm_res_hop_get_locked,
  	.hs_put_locked  = ldlm_res_hop_put_locked,
  	.hs_put	 = ldlm_res_hop_put
  };
  
  struct ldlm_ns_hash_def {
  	ldlm_ns_type_t  nsd_type;
  	/** hash bucket bits */
  	unsigned	nsd_bkt_bits;
  	/** hash bits */
  	unsigned	nsd_all_bits;
  	/** hash operations */
  	cfs_hash_ops_t *nsd_hops;
  };
  
  struct ldlm_ns_hash_def ldlm_ns_hash_defs[] = {
  	{
  		.nsd_type       = LDLM_NS_TYPE_MDC,
  		.nsd_bkt_bits   = 11,
  		.nsd_all_bits   = 16,
  		.nsd_hops       = &ldlm_ns_fid_hash_ops,
  	},
  	{
  		.nsd_type       = LDLM_NS_TYPE_MDT,
  		.nsd_bkt_bits   = 14,
  		.nsd_all_bits   = 21,
  		.nsd_hops       = &ldlm_ns_fid_hash_ops,
  	},
  	{
  		.nsd_type       = LDLM_NS_TYPE_OSC,
  		.nsd_bkt_bits   = 8,
  		.nsd_all_bits   = 12,
  		.nsd_hops       = &ldlm_ns_hash_ops,
  	},
  	{
  		.nsd_type       = LDLM_NS_TYPE_OST,
  		.nsd_bkt_bits   = 11,
  		.nsd_all_bits   = 17,
  		.nsd_hops       = &ldlm_ns_hash_ops,
  	},
  	{
  		.nsd_type       = LDLM_NS_TYPE_MGC,
  		.nsd_bkt_bits   = 4,
  		.nsd_all_bits   = 4,
  		.nsd_hops       = &ldlm_ns_hash_ops,
  	},
  	{
  		.nsd_type       = LDLM_NS_TYPE_MGT,
  		.nsd_bkt_bits   = 4,
  		.nsd_all_bits   = 4,
  		.nsd_hops       = &ldlm_ns_hash_ops,
  	},
  	{
  		.nsd_type       = LDLM_NS_TYPE_UNKNOWN,
  	},
  };
  
  /**
   * Create and initialize new empty namespace.
   */
  struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name,
  					  ldlm_side_t client,
  					  ldlm_appetite_t apt,
  					  ldlm_ns_type_t ns_type)
  {
  	struct ldlm_namespace *ns = NULL;
  	struct ldlm_ns_bucket *nsb;
  	struct ldlm_ns_hash_def    *nsd;
  	struct cfs_hash_bd	  bd;
  	int		    idx;
  	int		    rc;
  
  	LASSERT(obd != NULL);
  
  	rc = ldlm_get_ref();
  	if (rc) {
  		CERROR("ldlm_get_ref failed: %d\n", rc);
  		return NULL;
  	}
  
  	for (idx = 0;; idx++) {
  		nsd = &ldlm_ns_hash_defs[idx];
  		if (nsd->nsd_type == LDLM_NS_TYPE_UNKNOWN) {
  			CERROR("Unknown type %d for ns %s\n", ns_type, name);
  			goto out_ref;
  		}
  
  		if (nsd->nsd_type == ns_type)
  			break;
  	}
  
  	ns = kzalloc(sizeof(*ns), GFP_NOFS);
  	if (!ns)
  		goto out_ref;
  
  	ns->ns_rs_hash = cfs_hash_create(name,
  					 nsd->nsd_all_bits, nsd->nsd_all_bits,
  					 nsd->nsd_bkt_bits, sizeof(*nsb),
  					 CFS_HASH_MIN_THETA,
  					 CFS_HASH_MAX_THETA,
  					 nsd->nsd_hops,
  					 CFS_HASH_DEPTH |
  					 CFS_HASH_BIGNAME |
  					 CFS_HASH_SPIN_BKTLOCK |
  					 CFS_HASH_NO_ITEMREF);
  	if (ns->ns_rs_hash == NULL)
  		goto out_ns;
  
  	cfs_hash_for_each_bucket(ns->ns_rs_hash, &bd, idx) {
  		nsb = cfs_hash_bd_extra_get(ns->ns_rs_hash, &bd);
  		at_init(&nsb->nsb_at_estimate, ldlm_enqueue_min, 0);
  		nsb->nsb_namespace = ns;
  	}
  
  	ns->ns_obd      = obd;
  	ns->ns_appetite = apt;
  	ns->ns_client   = client;
  
  	INIT_LIST_HEAD(&ns->ns_list_chain);
  	INIT_LIST_HEAD(&ns->ns_unused_list);
  	spin_lock_init(&ns->ns_lock);
  	atomic_set(&ns->ns_bref, 0);
  	init_waitqueue_head(&ns->ns_waitq);
  
  	ns->ns_max_parallel_ast   = LDLM_DEFAULT_PARALLEL_AST_LIMIT;
  	ns->ns_nr_unused	  = 0;
  	ns->ns_max_unused	 = LDLM_DEFAULT_LRU_SIZE;
  	ns->ns_max_age	    = LDLM_DEFAULT_MAX_ALIVE;
  	ns->ns_orig_connect_flags = 0;
  	ns->ns_connect_flags      = 0;
  	ns->ns_stopping	   = 0;
  
  	rc = ldlm_namespace_sysfs_register(ns);
  	if (rc != 0) {
  		CERROR("Can't initialize ns sysfs, rc %d\n", rc);
  		goto out_hash;
  	}
  
  	rc = ldlm_namespace_debugfs_register(ns);
  	if (rc != 0) {
  		CERROR("Can't initialize ns proc, rc %d\n", rc);
  		goto out_sysfs;
  	}
  
  	idx = ldlm_namespace_nr_read(client);
  	rc = ldlm_pool_init(&ns->ns_pool, ns, idx, client);
  	if (rc) {
  		CERROR("Can't initialize lock pool, rc %d\n", rc);
  		goto out_proc;
  	}
  
  	ldlm_namespace_register(ns, client);
  	return ns;
  out_proc:
  	ldlm_namespace_debugfs_unregister(ns);
  out_sysfs:
  	ldlm_namespace_sysfs_unregister(ns);
  	ldlm_namespace_cleanup(ns, 0);
  out_hash:
  	cfs_hash_putref(ns->ns_rs_hash);
  out_ns:
  	kfree(ns);
  out_ref:
  	ldlm_put_ref();
  	return NULL;
  }
  EXPORT_SYMBOL(ldlm_namespace_new);
  
  extern struct ldlm_lock *ldlm_lock_get(struct ldlm_lock *lock);
  
  /**
   * Cancel and destroy all locks on a resource.
   *
   * If flags contains FL_LOCAL_ONLY, don't try to tell the server, just
   * clean up.  This is currently only used for recovery, and we make
   * certain assumptions as a result--notably, that we shouldn't cancel
   * locks with refs.
   */
  static void cleanup_resource(struct ldlm_resource *res, struct list_head *q,
  			     __u64 flags)
  {
  	struct list_head *tmp;
  	int rc = 0, client = ns_is_client(ldlm_res_to_ns(res));
  	bool local_only = !!(flags & LDLM_FL_LOCAL_ONLY);
  
  	do {
  		struct ldlm_lock *lock = NULL;
  
  		/* First, we look for non-cleaned-yet lock
  		 * all cleaned locks are marked by CLEANED flag. */
  		lock_res(res);
  		list_for_each(tmp, q) {
  			lock = list_entry(tmp, struct ldlm_lock,
  					      l_res_link);
  			if (lock->l_flags & LDLM_FL_CLEANED) {
  				lock = NULL;
  				continue;
  			}
  			LDLM_LOCK_GET(lock);
  			lock->l_flags |= LDLM_FL_CLEANED;
  			break;
  		}
  
  		if (lock == NULL) {
  			unlock_res(res);
  			break;
  		}
  
  		/* Set CBPENDING so nothing in the cancellation path
  		 * can match this lock. */
  		lock->l_flags |= LDLM_FL_CBPENDING;
  		lock->l_flags |= LDLM_FL_FAILED;
  		lock->l_flags |= flags;
  
  		/* ... without sending a CANCEL message for local_only. */
  		if (local_only)
  			lock->l_flags |= LDLM_FL_LOCAL_ONLY;
  
  		if (local_only && (lock->l_readers || lock->l_writers)) {
  			/* This is a little bit gross, but much better than the
  			 * alternative: pretend that we got a blocking AST from
  			 * the server, so that when the lock is decref'd, it
  			 * will go away ... */
  			unlock_res(res);
  			LDLM_DEBUG(lock, "setting FL_LOCAL_ONLY");
  			if (lock->l_completion_ast)
  				lock->l_completion_ast(lock, 0, NULL);
  			LDLM_LOCK_RELEASE(lock);
  			continue;
  		}
  
  		if (client) {
  			struct lustre_handle lockh;
  
  			unlock_res(res);
  			ldlm_lock2handle(lock, &lockh);
  			rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
  			if (rc)
  				CERROR("ldlm_cli_cancel: %d\n", rc);
  		} else {
  			ldlm_resource_unlink_lock(lock);
  			unlock_res(res);
  			LDLM_DEBUG(lock, "Freeing a lock still held by a client node");
  			ldlm_lock_destroy(lock);
  		}
  		LDLM_LOCK_RELEASE(lock);
  	} while (1);
  }
  
  static int ldlm_resource_clean(struct cfs_hash *hs, struct cfs_hash_bd *bd,
  			       struct hlist_node *hnode, void *arg)
  {
  	struct ldlm_resource *res = cfs_hash_object(hs, hnode);
  	__u64 flags = *(__u64 *)arg;
  
  	cleanup_resource(res, &res->lr_granted, flags);
  	cleanup_resource(res, &res->lr_converting, flags);
  	cleanup_resource(res, &res->lr_waiting, flags);
  
  	return 0;
  }
  
  static int ldlm_resource_complain(struct cfs_hash *hs, struct cfs_hash_bd *bd,
  				  struct hlist_node *hnode, void *arg)
  {
  	struct ldlm_resource  *res = cfs_hash_object(hs, hnode);
  
  	lock_res(res);
  	CERROR("%s: namespace resource "DLDLMRES
  	       " (%p) refcount nonzero (%d) after lock cleanup; forcing cleanup.\n",
  	       ldlm_ns_name(ldlm_res_to_ns(res)), PLDLMRES(res), res,
  	       atomic_read(&res->lr_refcount) - 1);
  
  	ldlm_resource_dump(D_ERROR, res);
  	unlock_res(res);
  	return 0;
  }
  
  /**
   * Cancel and destroy all locks in the namespace.
   *
   * Typically used during evictions when server notified client that it was
   * evicted and all of its state needs to be destroyed.
   * Also used during shutdown.
   */
  int ldlm_namespace_cleanup(struct ldlm_namespace *ns, __u64 flags)
  {
  	if (ns == NULL) {
  		CDEBUG(D_INFO, "NULL ns, skipping cleanup\n");
  		return ELDLM_OK;
  	}
  
  	cfs_hash_for_each_nolock(ns->ns_rs_hash, ldlm_resource_clean, &flags);
  	cfs_hash_for_each_nolock(ns->ns_rs_hash, ldlm_resource_complain, NULL);
  	return ELDLM_OK;
  }
  EXPORT_SYMBOL(ldlm_namespace_cleanup);
  
  /**
   * Attempts to free namespace.
   *
   * Only used when namespace goes away, like during an unmount.
   */
  static int __ldlm_namespace_free(struct ldlm_namespace *ns, int force)
  {
  	/* At shutdown time, don't call the cancellation callback */
  	ldlm_namespace_cleanup(ns, force ? LDLM_FL_LOCAL_ONLY : 0);
  
  	if (atomic_read(&ns->ns_bref) > 0) {
  		struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
  		int rc;
  
  		CDEBUG(D_DLMTRACE,
  		       "dlm namespace %s free waiting on refcount %d\n",
  		       ldlm_ns_name(ns), atomic_read(&ns->ns_bref));
  force_wait:
  		if (force)
  			lwi = LWI_TIMEOUT(obd_timeout * HZ / 4, NULL, NULL);
  
  		rc = l_wait_event(ns->ns_waitq,
  				  atomic_read(&ns->ns_bref) == 0, &lwi);
  
  		/* Forced cleanups should be able to reclaim all references,
  		 * so it's safe to wait forever... we can't leak locks... */
  		if (force && rc == -ETIMEDOUT) {
  			LCONSOLE_ERROR("Forced cleanup waiting for %s namespace with %d resources in use, (rc=%d)\n",
  				       ldlm_ns_name(ns),
  				       atomic_read(&ns->ns_bref), rc);
  			goto force_wait;
  		}
  
  		if (atomic_read(&ns->ns_bref)) {
  			LCONSOLE_ERROR("Cleanup waiting for %s namespace with %d resources in use, (rc=%d)\n",
  				       ldlm_ns_name(ns),
  				       atomic_read(&ns->ns_bref), rc);
  			return ELDLM_NAMESPACE_EXISTS;
  		}
  		CDEBUG(D_DLMTRACE, "dlm namespace %s free done waiting\n",
  		       ldlm_ns_name(ns));
  	}
  
  	return ELDLM_OK;
  }
  
  /**
   * Performs various cleanups for passed \a ns to make it drop refc and be
   * ready for freeing. Waits for refc == 0.
   *
   * The following is done:
   * (0) Unregister \a ns from its list to make inaccessible for potential
   * users like pools thread and others;
   * (1) Clear all locks in \a ns.
   */
  void ldlm_namespace_free_prior(struct ldlm_namespace *ns,
  			       struct obd_import *imp,
  			       int force)
  {
  	int rc;
  
  	if (!ns)
  		return;
  
  	spin_lock(&ns->ns_lock);
  	ns->ns_stopping = 1;
  	spin_unlock(&ns->ns_lock);
  
  	/*
  	 * Can fail with -EINTR when force == 0 in which case try harder.
  	 */
  	rc = __ldlm_namespace_free(ns, force);
  	if (rc != ELDLM_OK) {
  		if (imp) {
  			ptlrpc_disconnect_import(imp, 0);
  			ptlrpc_invalidate_import(imp);
  		}
  
  		/*
  		 * With all requests dropped and the import inactive
  		 * we are guaranteed all reference will be dropped.
  		 */
  		rc = __ldlm_namespace_free(ns, 1);
  		LASSERT(rc == 0);
  	}
  }
  
  /**
   * Performs freeing memory structures related to \a ns. This is only done
   * when ldlm_namespce_free_prior() successfully removed all resources
   * referencing \a ns and its refc == 0.
   */
  void ldlm_namespace_free_post(struct ldlm_namespace *ns)
  {
  	if (!ns)
  		return;
  
  	/* Make sure that nobody can find this ns in its list. */
  	ldlm_namespace_unregister(ns, ns->ns_client);
  	/* Fini pool _before_ parent proc dir is removed. This is important as
  	 * ldlm_pool_fini() removes own proc dir which is child to @dir.
  	 * Removing it after @dir may cause oops. */
  	ldlm_pool_fini(&ns->ns_pool);
  
  	ldlm_namespace_debugfs_unregister(ns);
  	cfs_hash_putref(ns->ns_rs_hash);
  	/* Namespace \a ns should be not on list at this time, otherwise
  	 * this will cause issues related to using freed \a ns in poold
  	 * thread. */
  	LASSERT(list_empty(&ns->ns_list_chain));
  	kfree(ns);
  	ldlm_put_ref();
  }
  
  /**
   * Cleanup the resource, and free namespace.
   * bug 12864:
   * Deadlock issue:
   * proc1: destroy import
   *	class_disconnect_export(grab cl_sem) ->
   *	      -> ldlm_namespace_free ->
   *	      -> ldebugfs_remove(grab _lprocfs_lock).
   * proc2: read proc info
   *	lprocfs_fops_read(grab _lprocfs_lock) ->
   *	      -> osc_rd_active, etc(grab cl_sem).
   *
   * So that I have to split the ldlm_namespace_free into two parts - the first
   * part ldlm_namespace_free_prior is used to cleanup the resource which is
   * being used; the 2nd part ldlm_namespace_free_post is used to unregister the
   * lprocfs entries, and then free memory. It will be called w/o cli->cl_sem
   * held.
   */
  void ldlm_namespace_free(struct ldlm_namespace *ns,
  			 struct obd_import *imp,
  			 int force)
  {
  	ldlm_namespace_free_prior(ns, imp, force);
  	ldlm_namespace_free_post(ns);
  }
  EXPORT_SYMBOL(ldlm_namespace_free);
  
  void ldlm_namespace_get(struct ldlm_namespace *ns)
  {
  	atomic_inc(&ns->ns_bref);
  }
  EXPORT_SYMBOL(ldlm_namespace_get);
  
  /* This is only for callers that care about refcount */
  int ldlm_namespace_get_return(struct ldlm_namespace *ns)
  {
  	return atomic_inc_return(&ns->ns_bref);
  }
  
  void ldlm_namespace_put(struct ldlm_namespace *ns)
  {
  	if (atomic_dec_and_lock(&ns->ns_bref, &ns->ns_lock)) {
  		wake_up(&ns->ns_waitq);
  		spin_unlock(&ns->ns_lock);
  	}
  }
  EXPORT_SYMBOL(ldlm_namespace_put);
  
  /** Register \a ns in the list of namespaces */
  void ldlm_namespace_register(struct ldlm_namespace *ns, ldlm_side_t client)
  {
  	mutex_lock(ldlm_namespace_lock(client));
  	LASSERT(list_empty(&ns->ns_list_chain));
  	list_add(&ns->ns_list_chain, ldlm_namespace_inactive_list(client));
  	ldlm_namespace_nr_inc(client);
  	mutex_unlock(ldlm_namespace_lock(client));
  }
  
  /** Unregister \a ns from the list of namespaces. */
  void ldlm_namespace_unregister(struct ldlm_namespace *ns, ldlm_side_t client)
  {
  	mutex_lock(ldlm_namespace_lock(client));
  	LASSERT(!list_empty(&ns->ns_list_chain));
  	/* Some asserts and possibly other parts of the code are still
  	 * using list_empty(&ns->ns_list_chain). This is why it is
  	 * important to use list_del_init() here. */
  	list_del_init(&ns->ns_list_chain);
  	ldlm_namespace_nr_dec(client);
  	mutex_unlock(ldlm_namespace_lock(client));
  }
  
  /** Should be called with ldlm_namespace_lock(client) taken. */
  void ldlm_namespace_move_to_active_locked(struct ldlm_namespace *ns,
  					  ldlm_side_t client)
  {
  	LASSERT(!list_empty(&ns->ns_list_chain));
  	LASSERT(mutex_is_locked(ldlm_namespace_lock(client)));
  	list_move_tail(&ns->ns_list_chain, ldlm_namespace_list(client));
  }
  
  /** Should be called with ldlm_namespace_lock(client) taken. */
  void ldlm_namespace_move_to_inactive_locked(struct ldlm_namespace *ns,
  					    ldlm_side_t client)
  {
  	LASSERT(!list_empty(&ns->ns_list_chain));
  	LASSERT(mutex_is_locked(ldlm_namespace_lock(client)));
  	list_move_tail(&ns->ns_list_chain,
  		       ldlm_namespace_inactive_list(client));
  }
  
  /** Should be called with ldlm_namespace_lock(client) taken. */
  struct ldlm_namespace *ldlm_namespace_first_locked(ldlm_side_t client)
  {
  	LASSERT(mutex_is_locked(ldlm_namespace_lock(client)));
  	LASSERT(!list_empty(ldlm_namespace_list(client)));
  	return container_of(ldlm_namespace_list(client)->next,
  		struct ldlm_namespace, ns_list_chain);
  }
  
  /** Create and initialize new resource. */
  static struct ldlm_resource *ldlm_resource_new(void)
  {
  	struct ldlm_resource *res;
  	int idx;
  
  	OBD_SLAB_ALLOC_PTR_GFP(res, ldlm_resource_slab, GFP_NOFS);
  	if (res == NULL)
  		return NULL;
  
  	INIT_LIST_HEAD(&res->lr_granted);
  	INIT_LIST_HEAD(&res->lr_converting);
  	INIT_LIST_HEAD(&res->lr_waiting);
  
  	/* Initialize interval trees for each lock mode. */
  	for (idx = 0; idx < LCK_MODE_NUM; idx++) {
  		res->lr_itree[idx].lit_size = 0;
  		res->lr_itree[idx].lit_mode = 1 << idx;
  		res->lr_itree[idx].lit_root = NULL;
  	}
  
  	atomic_set(&res->lr_refcount, 1);
  	spin_lock_init(&res->lr_lock);
  	lu_ref_init(&res->lr_reference);
  
  	/* The creator of the resource must unlock the mutex after LVB
  	 * initialization. */
  	mutex_init(&res->lr_lvb_mutex);
  	mutex_lock(&res->lr_lvb_mutex);
  
  	return res;
  }
  
  /**
   * Return a reference to resource with given name, creating it if necessary.
   * Args: namespace with ns_lock unlocked
   * Locks: takes and releases NS hash-lock and res->lr_lock
   * Returns: referenced, unlocked ldlm_resource or NULL
   */
  struct ldlm_resource *
  ldlm_resource_get(struct ldlm_namespace *ns, struct ldlm_resource *parent,
  		  const struct ldlm_res_id *name, ldlm_type_t type, int create)
  {
  	struct hlist_node     *hnode;
  	struct ldlm_resource *res;
  	struct cfs_hash_bd	 bd;
  	__u64		 version;
  	int		      ns_refcount = 0;
  
  	LASSERT(ns != NULL);
  	LASSERT(parent == NULL);
  	LASSERT(ns->ns_rs_hash != NULL);
  	LASSERT(name->name[0] != 0);
  
  	cfs_hash_bd_get_and_lock(ns->ns_rs_hash, (void *)name, &bd, 0);
  	hnode = cfs_hash_bd_lookup_locked(ns->ns_rs_hash, &bd, (void *)name);
  	if (hnode != NULL) {
  		cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 0);
  		res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  		/* Synchronize with regard to resource creation. */
  		if (ns->ns_lvbo && ns->ns_lvbo->lvbo_init) {
  			mutex_lock(&res->lr_lvb_mutex);
  			mutex_unlock(&res->lr_lvb_mutex);
  		}
  
  		if (unlikely(res->lr_lvb_len < 0)) {
  			ldlm_resource_putref(res);
  			res = NULL;
  		}
  		return res;
  	}
  
  	version = cfs_hash_bd_version_get(&bd);
  	cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 0);
  
  	if (create == 0)
  		return NULL;
  
  	LASSERTF(type >= LDLM_MIN_TYPE && type < LDLM_MAX_TYPE,
  		 "type: %d\n", type);
  	res = ldlm_resource_new();
  	if (!res)
  		return NULL;
  
  	res->lr_ns_bucket  = cfs_hash_bd_extra_get(ns->ns_rs_hash, &bd);
  	res->lr_name       = *name;
  	res->lr_type       = type;
  	res->lr_most_restr = LCK_NL;
  
  	cfs_hash_bd_lock(ns->ns_rs_hash, &bd, 1);
  	hnode = (version == cfs_hash_bd_version_get(&bd)) ?  NULL :
  		cfs_hash_bd_lookup_locked(ns->ns_rs_hash, &bd, (void *)name);
  
  	if (hnode != NULL) {
  		/* Someone won the race and already added the resource. */
  		cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1);
  		/* Clean lu_ref for failed resource. */
  		lu_ref_fini(&res->lr_reference);
  		/* We have taken lr_lvb_mutex. Drop it. */
  		mutex_unlock(&res->lr_lvb_mutex);
  		OBD_SLAB_FREE(res, ldlm_resource_slab, sizeof(*res));
  
  		res = hlist_entry(hnode, struct ldlm_resource, lr_hash);
  		/* Synchronize with regard to resource creation. */
  		if (ns->ns_lvbo && ns->ns_lvbo->lvbo_init) {
  			mutex_lock(&res->lr_lvb_mutex);
  			mutex_unlock(&res->lr_lvb_mutex);
  		}
  
  		if (unlikely(res->lr_lvb_len < 0)) {
  			ldlm_resource_putref(res);
  			res = NULL;
  		}
  		return res;
  	}
  	/* We won! Let's add the resource. */
  	cfs_hash_bd_add_locked(ns->ns_rs_hash, &bd, &res->lr_hash);
  	if (cfs_hash_bd_count_get(&bd) == 1)
  		ns_refcount = ldlm_namespace_get_return(ns);
  
  	cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1);
  	if (ns->ns_lvbo && ns->ns_lvbo->lvbo_init) {
  		int rc;
  
  		OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CREATE_RESOURCE, 2);
  		rc = ns->ns_lvbo->lvbo_init(res);
  		if (rc < 0) {
  			CERROR("%s: lvbo_init failed for resource %#llx:%#llx: rc = %d\n",
  			       ns->ns_obd->obd_name, name->name[0],
  			       name->name[1], rc);
  			kfree(res->lr_lvb_data);
  			res->lr_lvb_data = NULL;
  			res->lr_lvb_len = rc;
  			mutex_unlock(&res->lr_lvb_mutex);
  			ldlm_resource_putref(res);
  			return NULL;
  		}
  	}
  
  	/* We create resource with locked lr_lvb_mutex. */
  	mutex_unlock(&res->lr_lvb_mutex);
  
  	/* Let's see if we happened to be the very first resource in this
  	 * namespace. If so, and this is a client namespace, we need to move
  	 * the namespace into the active namespaces list to be patrolled by
  	 * the ldlm_poold. */
  	if (ns_is_client(ns) && ns_refcount == 1) {
  		mutex_lock(ldlm_namespace_lock(LDLM_NAMESPACE_CLIENT));
  		ldlm_namespace_move_to_active_locked(ns, LDLM_NAMESPACE_CLIENT);
  		mutex_unlock(ldlm_namespace_lock(LDLM_NAMESPACE_CLIENT));
  	}
  
  	return res;
  }
  EXPORT_SYMBOL(ldlm_resource_get);
  
  struct ldlm_resource *ldlm_resource_getref(struct ldlm_resource *res)
  {
  	LASSERT(res != NULL);
  	LASSERT(res != LP_POISON);
  	atomic_inc(&res->lr_refcount);
  	CDEBUG(D_INFO, "getref res: %p count: %d\n", res,
  	       atomic_read(&res->lr_refcount));
  	return res;
  }
  
  static void __ldlm_resource_putref_final(struct cfs_hash_bd *bd,
  					 struct ldlm_resource *res)
  {
  	struct ldlm_ns_bucket *nsb = res->lr_ns_bucket;
  
  	if (!list_empty(&res->lr_granted)) {
  		ldlm_resource_dump(D_ERROR, res);
  		LBUG();
  	}
  
  	if (!list_empty(&res->lr_converting)) {
  		ldlm_resource_dump(D_ERROR, res);
  		LBUG();
  	}
  
  	if (!list_empty(&res->lr_waiting)) {
  		ldlm_resource_dump(D_ERROR, res);
  		LBUG();
  	}
  
  	cfs_hash_bd_del_locked(nsb->nsb_namespace->ns_rs_hash,
  			       bd, &res->lr_hash);
  	lu_ref_fini(&res->lr_reference);
  	if (cfs_hash_bd_count_get(bd) == 0)
  		ldlm_namespace_put(nsb->nsb_namespace);
  }
  
  /* Returns 1 if the resource was freed, 0 if it remains. */
  int ldlm_resource_putref(struct ldlm_resource *res)
  {
  	struct ldlm_namespace *ns = ldlm_res_to_ns(res);
  	struct cfs_hash_bd   bd;
  
  	LASSERT_ATOMIC_GT_LT(&res->lr_refcount, 0, LI_POISON);
  	CDEBUG(D_INFO, "putref res: %p count: %d\n",
  	       res, atomic_read(&res->lr_refcount) - 1);
  
  	cfs_hash_bd_get(ns->ns_rs_hash, &res->lr_name, &bd);
  	if (cfs_hash_bd_dec_and_lock(ns->ns_rs_hash, &bd, &res->lr_refcount)) {
  		__ldlm_resource_putref_final(&bd, res);
  		cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1);
  		if (ns->ns_lvbo && ns->ns_lvbo->lvbo_free)
  			ns->ns_lvbo->lvbo_free(res);
  		OBD_SLAB_FREE(res, ldlm_resource_slab, sizeof(*res));
  		return 1;
  	}
  	return 0;
  }
  EXPORT_SYMBOL(ldlm_resource_putref);
  
  /* Returns 1 if the resource was freed, 0 if it remains. */
  int ldlm_resource_putref_locked(struct ldlm_resource *res)
  {
  	struct ldlm_namespace *ns = ldlm_res_to_ns(res);
  
  	LASSERT_ATOMIC_GT_LT(&res->lr_refcount, 0, LI_POISON);
  	CDEBUG(D_INFO, "putref res: %p count: %d\n",
  	       res, atomic_read(&res->lr_refcount) - 1);
  
  	if (atomic_dec_and_test(&res->lr_refcount)) {
  		struct cfs_hash_bd bd;
  
  		cfs_hash_bd_get(ldlm_res_to_ns(res)->ns_rs_hash,
  				&res->lr_name, &bd);
  		__ldlm_resource_putref_final(&bd, res);
  		cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1);
  		/* NB: ns_rs_hash is created with CFS_HASH_NO_ITEMREF,
  		 * so we should never be here while calling cfs_hash_del,
  		 * cfs_hash_for_each_nolock is the only case we can get
  		 * here, which is safe to release cfs_hash_bd_lock.
  		 */
  		if (ns->ns_lvbo && ns->ns_lvbo->lvbo_free)
  			ns->ns_lvbo->lvbo_free(res);
  		OBD_SLAB_FREE(res, ldlm_resource_slab, sizeof(*res));
  
  		cfs_hash_bd_lock(ns->ns_rs_hash, &bd, 1);
  		return 1;
  	}
  	return 0;
  }
  
  /**
   * Add a lock into a given resource into specified lock list.
   */
  void ldlm_resource_add_lock(struct ldlm_resource *res, struct list_head *head,
  			    struct ldlm_lock *lock)
  {
  	check_res_locked(res);
  
  	LDLM_DEBUG(lock, "About to add this lock:\n");
  
  	if (lock->l_flags & LDLM_FL_DESTROYED) {
  		CDEBUG(D_OTHER, "Lock destroyed, not adding to resource\n");
  		return;
  	}
  
  	LASSERT(list_empty(&lock->l_res_link));
  
  	list_add_tail(&lock->l_res_link, head);
  }
  
  /**
   * Insert a lock into resource after specified lock.
   *
   * Obtain resource description from the lock we are inserting after.
   */
  void ldlm_resource_insert_lock_after(struct ldlm_lock *original,
  				     struct ldlm_lock *new)
  {
  	struct ldlm_resource *res = original->l_resource;
  
  	check_res_locked(res);
  
  	ldlm_resource_dump(D_INFO, res);
  	LDLM_DEBUG(new, "About to insert this lock after %p:\n", original);
  
  	if (new->l_flags & LDLM_FL_DESTROYED) {
  		CDEBUG(D_OTHER, "Lock destroyed, not adding to resource\n");
  		goto out;
  	}
  
  	LASSERT(list_empty(&new->l_res_link));
  
  	list_add(&new->l_res_link, &original->l_res_link);
   out:;
  }
  
  void ldlm_resource_unlink_lock(struct ldlm_lock *lock)
  {
  	int type = lock->l_resource->lr_type;
  
  	check_res_locked(lock->l_resource);
  	if (type == LDLM_IBITS || type == LDLM_PLAIN)
  		ldlm_unlink_lock_skiplist(lock);
  	else if (type == LDLM_EXTENT)
  		ldlm_extent_unlink_lock(lock);
  	list_del_init(&lock->l_res_link);
  }
  EXPORT_SYMBOL(ldlm_resource_unlink_lock);
  
  void ldlm_res2desc(struct ldlm_resource *res, struct ldlm_resource_desc *desc)
  {
  	desc->lr_type = res->lr_type;
  	desc->lr_name = res->lr_name;
  }
  
  /**
   * Print information about all locks in all namespaces on this node to debug
   * log.
   */
  void ldlm_dump_all_namespaces(ldlm_side_t client, int level)
  {
  	struct list_head *tmp;
  
  	if (!((libcfs_debug | D_ERROR) & level))
  		return;
  
  	mutex_lock(ldlm_namespace_lock(client));
  
  	list_for_each(tmp, ldlm_namespace_list(client)) {
  		struct ldlm_namespace *ns;
  
  		ns = list_entry(tmp, struct ldlm_namespace, ns_list_chain);
  		ldlm_namespace_dump(level, ns);
  	}
  
  	mutex_unlock(ldlm_namespace_lock(client));
  }
  EXPORT_SYMBOL(ldlm_dump_all_namespaces);
  
  static int ldlm_res_hash_dump(struct cfs_hash *hs, struct cfs_hash_bd *bd,
  			      struct hlist_node *hnode, void *arg)
  {
  	struct ldlm_resource *res = cfs_hash_object(hs, hnode);
  	int    level = (int)(unsigned long)arg;
  
  	lock_res(res);
  	ldlm_resource_dump(level, res);
  	unlock_res(res);
  
  	return 0;
  }
  
  /**
   * Print information about all locks in this namespace on this node to debug
   * log.
   */
  void ldlm_namespace_dump(int level, struct ldlm_namespace *ns)
  {
  	if (!((libcfs_debug | D_ERROR) & level))
  		return;
  
  	CDEBUG(level, "--- Namespace: %s (rc: %d, side: %s)\n",
  	       ldlm_ns_name(ns), atomic_read(&ns->ns_bref),
  	       ns_is_client(ns) ? "client" : "server");
  
  	if (time_before(cfs_time_current(), ns->ns_next_dump))
  		return;
  
  	cfs_hash_for_each_nolock(ns->ns_rs_hash,
  				 ldlm_res_hash_dump,
  				 (void *)(unsigned long)level);
  	spin_lock(&ns->ns_lock);
  	ns->ns_next_dump = cfs_time_shift(10);
  	spin_unlock(&ns->ns_lock);
  }
  EXPORT_SYMBOL(ldlm_namespace_dump);
  
  /**
   * Print information about all locks in this resource to debug log.
   */
  void ldlm_resource_dump(int level, struct ldlm_resource *res)
  {
  	struct ldlm_lock *lock;
  	unsigned int granted = 0;
  
  	CLASSERT(RES_NAME_SIZE == 4);
  
  	if (!((libcfs_debug | D_ERROR) & level))
  		return;
  
  	CDEBUG(level, "--- Resource: "DLDLMRES" (%p) refcount = %d\n",
  	       PLDLMRES(res), res, atomic_read(&res->lr_refcount));
  
  	if (!list_empty(&res->lr_granted)) {
  		CDEBUG(level, "Granted locks (in reverse order):\n");
  		list_for_each_entry_reverse(lock, &res->lr_granted,
  						l_res_link) {
  			LDLM_DEBUG_LIMIT(level, lock, "###");
  			if (!(level & D_CANTMASK) &&
  			    ++granted > ldlm_dump_granted_max) {
  				CDEBUG(level, "only dump %d granted locks to avoid DDOS.\n",
  				       granted);
  				break;
  			}
  		}
  	}
  	if (!list_empty(&res->lr_converting)) {
  		CDEBUG(level, "Converting locks:\n");
  		list_for_each_entry(lock, &res->lr_converting, l_res_link)
  			LDLM_DEBUG_LIMIT(level, lock, "###");
  	}
  	if (!list_empty(&res->lr_waiting)) {
  		CDEBUG(level, "Waiting locks:\n");
  		list_for_each_entry(lock, &res->lr_waiting, l_res_link)
  			LDLM_DEBUG_LIMIT(level, lock, "###");
  	}
  }
  