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 #define DEBUG_SUBSYSTEM S_LDLM
  14
  15 #include <linux/lustre_dlm.h>
  16
  17 kmem_cache_t *ldlm_resource_slab, *ldlm_lock_slab;
  18
  19 struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obddev,
  20                                           __u32 local)
  21 {
  22         struct ldlm_namespace *ns;
  23         struct list_head *bucket;
  24
  25         OBD_ALLOC(ns, sizeof(*ns));
  26         if (!ns) {
  27                 LBUG();
  28                 RETURN(NULL);
  29         }
  30         ns->ns_hash = vmalloc(sizeof(*ns->ns_hash) * RES_HASH_SIZE);
  31         if (!ns->ns_hash) {
  32                 OBD_FREE(ns, sizeof(*ns));
  33                 LBUG();
  34                 RETURN(NULL);
  35         }
  36
  37         ns->ns_obddev = obddev;
  38         INIT_LIST_HEAD(&ns->ns_root_list);
  39         ns->ns_lock = SPIN_LOCK_UNLOCKED;
  40         ns->ns_refcount = 0;
  41         ns->ns_local = local;
  42
  43         for (bucket = ns->ns_hash + RES_HASH_SIZE - 1; bucket >= ns->ns_hash;
  44              bucket--)
  45                 INIT_LIST_HEAD(bucket);
  46
  47         return ns;
  48 }
  49
  50 static int cleanup_resource(struct ldlm_resource *res, struct list_head *q)
  51 {
  52         struct list_head *tmp, *pos;
  53         int rc = 0;
  54
  55         list_for_each_safe(tmp, pos, q) {
  56                 struct ldlm_lock *lock;
  57
  58                 if (rc) {
  59                         /* Res was already cleaned up. */
  60                         LBUG();
  61                 }
  62
  63                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
  64                 spin_lock(&lock->l_lock);
  65                 ldlm_resource_del_lock(lock);
  66                 ldlm_lock_free(lock);
  67
  68                 rc = ldlm_resource_put(res);
  69         }
  70
  71         return rc;
  72 }
  73
  74 int ldlm_namespace_free(struct ldlm_namespace *ns)
  75 {
  76         struct list_head *tmp, *pos;
  77         int i, rc;
  78
  79         /* We should probably take the ns_lock, but then ldlm_resource_put
  80          * couldn't take it.  Hmm. */
  81         for (i = 0; i < RES_HASH_SIZE; i++) {
  82                 list_for_each_safe(tmp, pos, &(ns->ns_hash[i])) {
  83                         struct ldlm_resource *res;
  84                         res = list_entry(tmp, struct ldlm_resource, lr_hash);
  85
  86                         spin_lock(&res->lr_lock);
  87                         rc = cleanup_resource(res, &res->lr_granted);
  88                         if (!rc)
  89                                 rc = cleanup_resource(res, &res->lr_converting);
  90                         if (!rc)
  91                                 rc = cleanup_resource(res, &res->lr_waiting);
  92
  93                         if (rc == 0) {
  94                                 CERROR("Resource refcount nonzero after lock "
  95                                        "cleanup; forcing cleanup.\n");
  96                                 res->lr_refcount = 1;
  97                                 rc = ldlm_resource_put(res);
  98                         }
  99                 }
 100         }
 101
 102         vfree(ns->ns_hash /* , sizeof(struct list_head) * RES_HASH_SIZE */);
 103         OBD_FREE(ns, sizeof(*ns));
 104
 105         return ELDLM_OK;
 106 }
 107
 108 static __u32 ldlm_hash_fn(struct ldlm_resource *parent, __u64 *name)
 109 {
 110         __u32 hash = 0;
 111         int i;
 112
 113         for (i = 0; i < RES_NAME_SIZE; i++)
 114                 hash += name[i];
 115
 116         hash += (__u32)((unsigned long)parent >> 4);
 117
 118         return (hash & RES_HASH_MASK);
 119 }
 120
 121 static struct ldlm_resource *ldlm_resource_new(void)
 122 {
 123         struct ldlm_resource *res;
 124
 125         res = kmem_cache_alloc(ldlm_resource_slab, SLAB_KERNEL);
 126         if (res == NULL) {
 127                 LBUG();
 128                 return NULL;
 129         }
 130         memset(res, 0, sizeof(*res));
 131
 132         INIT_LIST_HEAD(&res->lr_children);
 133         INIT_LIST_HEAD(&res->lr_childof);
 134         INIT_LIST_HEAD(&res->lr_granted);
 135         INIT_LIST_HEAD(&res->lr_converting);
 136         INIT_LIST_HEAD(&res->lr_waiting);
 137
 138         res->lr_lock = SPIN_LOCK_UNLOCKED;
 139         res->lr_refcount = 1;
 140
 141         return res;
 142 }
 143
 144 /* Args: locked namespace
 145  * Returns: newly-allocated, referenced, unlocked resource */
 146 static struct ldlm_resource *ldlm_resource_add(struct ldlm_namespace *ns,
 147                                                struct ldlm_resource *parent,
 148                                                __u64 *name, __u32 type)
 149 {
 150         struct list_head *bucket;
 151         struct ldlm_resource *res;
 152         ENTRY;
 153
 154         if (type < 0 || type > LDLM_MAX_TYPE) {
 155                 LBUG();
 156                 RETURN(NULL);
 157         }
 158
 159         res = ldlm_resource_new();
 160         if (!res) {
 161                 LBUG();
 162                 RETURN(NULL);
 163         }
 164
 165         memcpy(res->lr_name, name, sizeof(res->lr_name));
 166         res->lr_namespace = ns;
 167         ns->ns_refcount++;
 168
 169         res->lr_type = type;
 170         res->lr_most_restr = LCK_NL;
 171
 172         bucket = ns->ns_hash + ldlm_hash_fn(parent, name);
 173         list_add(&res->lr_hash, bucket);
 174
 175         if (parent == NULL) {
 176                 res->lr_parent = res;
 177                 list_add(&res->lr_rootlink, &ns->ns_root_list);
 178         } else {
 179                 res->lr_parent = parent;
 180                 list_add(&res->lr_childof, &parent->lr_children);
 181         }
 182
 183         RETURN(res);
 184 }
 185
 186 /* Args: unlocked namespace
 187  * Locks: takes and releases ns->ns_lock and res->lr_lock
 188  * Returns: referenced, unlocked ldlm_resource or NULL */
 189 struct ldlm_resource *ldlm_resource_get(struct ldlm_namespace *ns,
 190                                         struct ldlm_resource *parent,
 191                                         __u64 *name, __u32 type, int create)
 192 {
 193         struct list_head *bucket;
 194         struct list_head *tmp = bucket;
 195         struct ldlm_resource *res = NULL;
 196
 197         ENTRY;
 198
 199         if (ns->ns_hash == NULL)
 200                 RETURN(NULL);
 201
 202         spin_lock(&ns->ns_lock);
 203         bucket = ns->ns_hash + ldlm_hash_fn(parent, name);
 204
 205         list_for_each(tmp, bucket) {
 206                 struct ldlm_resource *chk;
 207                 chk = list_entry(tmp, struct ldlm_resource, lr_hash);
 208
 209                 if (memcmp(chk->lr_name, name, sizeof(chk->lr_name)) == 0) {
 210                         res = chk;
 211                         spin_lock(&res->lr_lock);
 212                         res->lr_refcount++;
 213                         spin_unlock(&res->lr_lock);
 214                         EXIT;
 215                         break;
 216                 }
 217         }
 218
 219         if (res == NULL && create)
 220                 res = ldlm_resource_add(ns, parent, name, type);
 221         spin_unlock(&ns->ns_lock);
 222
 223         RETURN(res);
 224 }
 225
 226 /* Args: locked resource
 227  * Locks: takes and releases res->lr_lock
 228  *        takes and releases ns->ns_lock iff res->lr_refcount falls to 0
 229  */
 230 int ldlm_resource_put(struct ldlm_resource *res)
 231 {
 232         int rc = 0;
 233
 234         if (res->lr_refcount == 1) {
 235                 struct ldlm_namespace *ns = res->lr_namespace;
 236                 ENTRY;
 237
 238                 spin_unlock(&res->lr_lock);
 239                 spin_lock(&ns->ns_lock);
 240                 spin_lock(&res->lr_lock);
 241
 242                 if (res->lr_refcount != 1) {
 243                         spin_unlock(&ns->ns_lock);
 244                         goto out;
 245                 }
 246
 247                 if (!list_empty(&res->lr_granted))
 248                         LBUG();
 249
 250                 if (!list_empty(&res->lr_converting))
 251                         LBUG();
 252
 253                 if (!list_empty(&res->lr_waiting))
 254                         LBUG();
 255
 256                 if (!list_empty(&res->lr_children))
 257                         LBUG();
 258
 259                 ns->ns_refcount--;
 260                 list_del(&res->lr_hash);
 261                 list_del(&res->lr_rootlink);
 262                 list_del(&res->lr_childof);
 263
 264                 kmem_cache_free(ldlm_resource_slab, res);
 265                 spin_unlock(&ns->ns_lock);
 266                 rc = 1;
 267         } else {
 268                 ENTRY;
 269         out:
 270                 res->lr_refcount--;
 271                 if (res->lr_refcount < 0)
 272                         LBUG();
 273         }
 274
 275         RETURN(rc);
 276 }
 277
 278 /* Must be called with resource->lr_lock taken */
 279 void ldlm_resource_add_lock(struct ldlm_resource *res, struct list_head *head,
 280                             struct ldlm_lock *lock)
 281 {
 282         list_add(&lock->l_res_link, head);
 283         res->lr_refcount++;
 284 }
 285
 286 /* Must be called with resource->lr_lock taken */
 287 void ldlm_resource_del_lock(struct ldlm_lock *lock)
 288 {
 289         list_del_init(&lock->l_res_link);
 290         lock->l_resource->lr_refcount--;
 291 }
 292
 293 int ldlm_get_resource_handle(struct ldlm_resource *res, struct ldlm_handle *h)
 294 {
 295         LBUG();
 296         return 0;
 297 }
 298
 299 void ldlm_res2desc(struct ldlm_resource *res, struct ldlm_resource_desc *desc)
 300 {
 301         desc->lr_type = res->lr_type;
 302         memcpy(desc->lr_name, res->lr_name, sizeof(desc->lr_name));
 303         memcpy(desc->lr_version, res->lr_version, sizeof(desc->lr_version));
 304 }
 305
 306 void ldlm_resource_dump(struct ldlm_resource *res)
 307 {
 308         struct list_head *tmp;
 309         char name[256];
 310
 311         if (RES_NAME_SIZE != 3)
 312                 LBUG();
 313
 314         snprintf(name, sizeof(name), "%Lx %Lx %Lx",
 315                  (unsigned long long)res->lr_name[0],
 316                  (unsigned long long)res->lr_name[1],
 317                  (unsigned long long)res->lr_name[2]);
 318
 319         CDEBUG(D_OTHER, "--- Resource: %p (%s)\n", res, name);
 320         CDEBUG(D_OTHER, "Namespace: %p\n", res->lr_namespace);
 321         CDEBUG(D_OTHER, "Parent: %p, root: %p\n", res->lr_parent, res->lr_root);
 322
 323         CDEBUG(D_OTHER, "Granted locks:\n");
 324         list_for_each(tmp, &res->lr_granted) {
 325                 struct ldlm_lock *lock;
 326                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 327                 ldlm_lock_dump(lock);
 328         }
 329
 330         CDEBUG(D_OTHER, "Converting locks:\n");
 331         list_for_each(tmp, &res->lr_converting) {
 332                 struct ldlm_lock *lock;
 333                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 334                 ldlm_lock_dump(lock);
 335         }
 336
 337         CDEBUG(D_OTHER, "Waiting locks:\n");
 338         list_for_each(tmp, &res->lr_waiting) {
 339                 struct ldlm_lock *lock;
 340                 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 341                 ldlm_lock_dump(lock);
 342         }
 343 }