lustre/ldlm/ldlm_resource.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2002 Cluster File Systems, Inc.
   5  *
   6  * This code is issued under the GNU General Public License.
   7  * See the file COPYING in this distribution
   8  *
   9  * by Cluster File Systems, Inc.
  10  */
  11
  12 #define EXPORT_SYMTAB
  13
  14 #include <linux/version.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <asm/unistd.h>
  18
  19 #define DEBUG_SUBSYSTEM S_LDLM
  20
  21 #include <linux/obd_support.h>
  22 #include <linux/obd_class.h>
  23
  24 #include <linux/lustre_dlm.h>
  25
  26 kmem_cache_t *ldlm_resource_slab;
  27 kmem_cache_t *ldlm_lock_slab;
  28
  29 struct ldlm_namespace *ldlm_namespace_find(struct obd_device *obddev, __u32 id)
  30 {
  31         struct list_head *tmp;
  32         struct ldlm_namespace *res;
  33
  34         res = NULL;
  35         list_for_each(tmp, &obddev->u.ldlm.ldlm_namespaces) {
  36                 struct ldlm_namespace *chk;
  37                 chk = list_entry(tmp, struct ldlm_namespace, ns_link);
  38
  39                 if ( chk->ns_id == id ) {
  40                         res = chk;
  41                         break;
  42                 }
  43         }
  44
  45         return res;
  46 }
  47
  48 /* this must be called with ldlm_lock(obddev) held */
  49 static void res_hash_init(struct ldlm_namespace *ns)
  50 {
  51         struct list_head *res_hash;
  52         struct list_head *bucket;
  53
  54         if (ns->ns_hash != NULL)
  55                 return;
  56
  57         /* FIXME: this memory appears to be leaked */
  58         OBD_ALLOC(res_hash, sizeof(*res_hash) * RES_HASH_SIZE);
  59         if (!res_hash)
  60                 LBUG();
  61
  62         for (bucket = res_hash + RES_HASH_SIZE - 1; bucket >= res_hash;
  63              bucket--)
  64                 INIT_LIST_HEAD(bucket);
  65
  66         ns->ns_hash = res_hash;
  67 }
  68
  69 struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obddev, __u32 id)
  70 {
  71         struct ldlm_namespace *ns;
  72
  73         if (ldlm_namespace_find(obddev, id))
  74                 LBUG();
  75
  76         OBD_ALLOC(ns, sizeof(*ns));
  77         if (!ns)
  78                 LBUG();
  79
  80         ns->ns_id = id;
  81         INIT_LIST_HEAD(&ns->ns_root_list);
  82
  83         list_add(&ns->ns_link, &obddev->u.ldlm.ldlm_namespaces);
  84
  85         res_hash_init(ns);
  86         atomic_set(&ns->ns_refcount, 0);
  87
  88         return ns;
  89 }
  90
  91 int ldlm_namespace_free(struct ldlm_namespace *ns)
  92 {
  93         if (atomic_read(&ns->ns_refcount))
  94                 return -EBUSY;
  95
  96         list_del(&ns->ns_link);
  97         OBD_FREE(ns->ns_hash, sizeof(struct list_head) * RES_HASH_SIZE);
  98         OBD_FREE(ns, sizeof(*ns));
  99
 100         return 0;
 101 }
 102
 103 static __u32 ldlm_hash_fn(struct ldlm_resource *parent, __u64 *name)
 104 {
 105         __u32 hash = 0;
 106         int i;
 107
 108         for (i = 0; i < RES_NAME_SIZE; i++)
 109                 hash += name[i];
 110
 111         hash += (__u32)((unsigned long)parent >> 4);
 112
 113         return (hash & RES_HASH_MASK);
 114 }
 115
 116 static struct ldlm_resource *ldlm_resource_new(void)
 117 {
 118         struct ldlm_resource *res;
 119
 120         res = kmem_cache_alloc(ldlm_resource_slab, SLAB_KERNEL);
 121         if (res == NULL)
 122                 LBUG();
 123         memset(res, 0, sizeof(*res));
 124
 125         INIT_LIST_HEAD(&res->lr_children);
 126         INIT_LIST_HEAD(&res->lr_childof);
 127         INIT_LIST_HEAD(&res->lr_granted);
 128         INIT_LIST_HEAD(&res->lr_converting);
 129         INIT_LIST_HEAD(&res->lr_waiting);
 130
 131         res->lr_lock = SPIN_LOCK_UNLOCKED;
 132
 133         atomic_set(&res->lr_refcount, 1);
 134
 135         return res;
 136 }
 137
 138 /* ldlm_lock(obddev) must be taken before calling resource_add */
 139 static struct ldlm_resource *ldlm_resource_add(struct ldlm_namespace *ns,
 140                                                struct ldlm_resource *parent,
 141                                                __u64 *name, __u32 type)
 142 {
 143         struct list_head *bucket;
 144         struct ldlm_resource *res;
 145
 146         bucket = ns->ns_hash + ldlm_hash_fn(parent, name);
 147
 148         res = ldlm_resource_new();
 149         if (!res)
 150                 LBUG();
 151
 152         memcpy(res->lr_name, name, sizeof(res->lr_name));
 153         res->lr_namespace = ns;
 154         if (type < 0 || type > LDLM_MAX_TYPE)
 155                 LBUG();
 156
 157         res->lr_type = type;
 158         res->lr_most_restr = LCK_NL;
 159         list_add(&res->lr_hash, bucket);
 160         atomic_inc(&ns->ns_refcount);
 161         if (parent == NULL) {
 162                 res->lr_parent = res;
 163                 list_add(&res->lr_rootlink, &ns->ns_root_list);
 164         } else {
 165                 res->lr_parent = parent;
 166                 list_add(&res->lr_childof, &parent->lr_children);
 167         }
 168
 169         return res;
 170 }
 171
 172 struct ldlm_resource *ldlm_resource_get(struct ldlm_namespace *ns,
 173                                         struct ldlm_resource *parent,
 174                                         __u64 *name, __u32 type, int create)
 175 {
 176         struct list_head *bucket;
 177         struct list_head *tmp = bucket;
 178         struct ldlm_resource *res;
 179
 180         ENTRY;
 181
 182         if (ns->ns_hash == NULL)
 183                 RETURN(NULL);
 184         bucket = ns->ns_hash + ldlm_hash_fn(parent, name);
 185
 186         res = NULL;
 187         list_for_each(tmp, bucket) {
 188                 struct ldlm_resource *chk;
 189                 chk = list_entry(tmp, struct ldlm_resource, lr_hash);
 190
 191                 if (memcmp(chk->lr_name, name, sizeof(chk->lr_name)) == 0) {
 192                         res = chk;
 193                         atomic_inc(&res->lr_refcount);
 194                         break;
 195                 }
 196         }
 197
 198         if (res == NULL && create)
 199                 res = ldlm_resource_add(ns, parent, name, type);
 200
 201         RETURN(res);
 202 }
 203
 204 int ldlm_resource_put(struct ldlm_resource *res)
 205 {
 206         int rc = 0;
 207
 208         if (atomic_read(&res->lr_refcount) <= 0)
 209                 LBUG();
 210
 211         if (atomic_dec_and_test(&res->lr_refcount)) {
 212                 if (!list_empty(&res->lr_granted))
 213                         LBUG();
 214
 215                 if (!list_empty(&res->lr_converting))
 216                         LBUG();
 217
 218                 if (!list_empty(&res->lr_waiting))
 219                         LBUG();
 220
 221                 atomic_dec(&res->lr_namespace->ns_refcount);
 222                 list_del(&res->lr_hash);
 223                 list_del(&res->lr_rootlink);
 224                 list_del(&res->lr_childof);
 225
 226                 kmem_cache_free(ldlm_resource_slab, res);
 227                 rc = 1;
 228         }
 229
 230         return rc;
 231 }
 232
 233 void ldlm_resource_add_lock(struct ldlm_resource *res, struct list_head *head,
 234                             struct ldlm_lock *lock)
 235 {
 236         list_add(&lock->l_res_link, head);
 237         atomic_inc(&res->lr_refcount);
 238 }
 239
 240 void ldlm_resource_del_lock(struct ldlm_lock *lock)
 241 {
 242         list_del(&lock->l_res_link);
 243         atomic_dec(&lock->l_resource->lr_refcount);
 244 }
 245
 246 int ldlm_get_resource_handle(struct ldlm_resource *res, struct ldlm_handle *h)
 247 {
 248         LBUG();
 249         return 0;
 250 }
 251
 252 void ldlm_resource_dump(struct ldlm_resource *res)
 253 {
 254         struct list_head *tmp;
 255         char name[256];
 256
 257         if (RES_NAME_SIZE != 3)
 258                 LBUG();
 259
 260         snprintf(name, sizeof(name), "%Lx %Lx %Lx",
 261                  res->lr_name[0], res->lr_name[1], res->lr_name[2]);
 262
 263         CDEBUG(D_OTHER, "--- Resource: %p (%s)\n", res, name);
 264         CDEBUG(D_OTHER, "Namespace: %p (%u)\n", res->lr_namespace,
 265                res->lr_namespace->ns_id);
 266         CDEBUG(D_OTHER, "Parent: %p, root: %p\n", res->lr_parent, res->lr_root);
 267
 268         CDEBUG(D_OTHER, "Granted locks:\n");
 269         list_for_each(tmp, &res->lr_granted) {
 270                 struct ldlm_lock *lock;
 271                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 272                 ldlm_lock_dump(lock);
 273         }
 274
 275         CDEBUG(D_OTHER, "Converting locks:\n");
 276         list_for_each(tmp, &res->lr_converting) {
 277                 struct ldlm_lock *lock;
 278                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 279                 ldlm_lock_dump(lock);
 280         }
 281
 282         CDEBUG(D_OTHER, "Waiting locks:\n");
 283         list_for_each(tmp, &res->lr_waiting) {
 284                 struct ldlm_lock *lock;
 285                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 286                 ldlm_lock_dump(lock);
 287         }
 288 }
 289