/*
 * 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, 2015, 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;
int ldlm_cli_namespace_nr;

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 */
static 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.
 */
static 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)
                lprocfs_free_stats(&ns->ns_stats);
}

static void ldlm_namespace_sysfs_unregister(struct ldlm_namespace *ns)
{
        kobject_put(&ns->ns_kobj);
        wait_for_completion(&ns->ns_kobj_unregister);
}

static 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) {
                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)
                        return -ENOMEM;
                ns->ns_debugfs_entry = ns_entry;
        }

        return 0;
}

#undef MAX_STRING_SIZE

static struct ldlm_resource *ldlm_resource_getref(struct ldlm_resource *res)
{
        LASSERT(res);
        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 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);
}

static struct cfs_hash_ops 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
};

static struct cfs_hash_ops 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 {
        enum ldlm_ns_type nsd_type;
        /** hash bucket bits */
        unsigned        nsd_bkt_bits;
        /** hash bits */
        unsigned        nsd_all_bits;
        /** hash operations */
        struct cfs_hash_ops *nsd_hops;
};

static 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,
        },
};

/** Register \a ns in the list of namespaces */
static 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_cli_inactive_namespace_list);
        ldlm_namespace_nr_inc(client);
        mutex_unlock(ldlm_namespace_lock(client));
}

/**
 * Create and initialize new empty namespace.
 */
struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name,
                                          ldlm_side_t client,
                                          enum ldlm_appetite apt,
                                          enum ldlm_ns_type 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);

        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)
                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;
        bool local_only = !!(flags & LDLM_FL_LOCAL_ONLY);

        do {
                struct ldlm_lock *lock = NULL;
                struct lustre_handle lockh;

                /* 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) {
                        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;
                }

                unlock_res(res);
                ldlm_lock2handle(lock, &lockh);
                rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
                if (rc)
                        CERROR("ldlm_cli_cancel: %d\n", rc);
                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_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) {
                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);
        }
}

/** Unregister \a ns from the list of namespaces. */
static 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));
}

/**
 * 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);
        ldlm_namespace_sysfs_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();
}

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 */
static 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);

/** 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_cli_inactive_namespace_list);
}

/** 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;

        res = kmem_cache_zalloc(ldlm_resource_slab, GFP_NOFS);
        if (!res)
                return NULL;

        INIT_LIST_HEAD(&res->lr_granted);
        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, enum ldlm_type type,
                  int create)
{
        struct hlist_node     *hnode;
        struct ldlm_resource *res;
        struct cfs_hash_bd       bd;
        __u64            version;
        int                   ns_refcount = 0;

        LASSERT(!parent);
        LASSERT(ns->ns_rs_hash);
        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) {
                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;

        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) {
                /* 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);
                kmem_cache_free(ldlm_resource_slab, 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);
                        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_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);

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_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);
                kmem_cache_free(ldlm_resource_slab, 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);
                kmem_cache_free(ldlm_resource_slab, 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);
}

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: client)\n",
               ldlm_ns_name(ns), atomic_read(&ns->ns_bref));

        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_waiting)) {
                CDEBUG(level, "Waiting locks:\n");
                list_for_each_entry(lock, &res->lr_waiting, l_res_link)
                        LDLM_DEBUG_LIMIT(level, lock, "###");
        }
}