lustre/obdclass/genops.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  Copyright (c) 2001-2003 Cluster File Systems, Inc.
   5  *
   6  *   This file is part of Lustre, http://www.lustre.org.
   7  *
   8  *   Lustre is free software; you can redistribute it and/or
   9  *   modify it under the terms of version 2 of the GNU General Public
  10  *   License as published by the Free Software Foundation.
  11  *
  12  *   Lustre is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with Lustre; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  * These are the only exported functions, they provide some generic
  22  * infrastructure for managing object devices
  23  */
  24
  25 #define DEBUG_SUBSYSTEM S_CLASS
  26 #ifdef __KERNEL__
  27 #include <linux/kmod.h>   /* for request_module() */
  28 #include <linux/module.h>
  29 #include <linux/obd_class.h>
  30 #include <linux/random.h>
  31 #include <linux/slab.h>
  32 #include <linux/pagemap.h>
  33 #else
  34 #include <liblustre.h>
  35 #include <linux/obd_class.h>
  36 #include <linux/obd.h>
  37 #endif
  38 #include <linux/lprocfs_status.h>
  39
  40 extern struct list_head obd_types;
  41 static spinlock_t obd_types_lock = SPIN_LOCK_UNLOCKED;
  42 kmem_cache_t *obdo_cachep = NULL;
  43 kmem_cache_t *import_cachep = NULL;
  44
  45 int (*ptlrpc_put_connection_superhack)(struct ptlrpc_connection *c);
  46 void (*ptlrpc_abort_inflight_superhack)(struct obd_import *imp);
  47
  48 /*
  49  * support functions: we could use inter-module communication, but this
  50  * is more portable to other OS's
  51  */
  52 static struct obd_type *class_search_type(char *name)
  53 {
  54         struct list_head *tmp;
  55         struct obd_type *type;
  56
  57         spin_lock(&obd_types_lock);
  58         list_for_each(tmp, &obd_types) {
  59                 type = list_entry(tmp, struct obd_type, typ_chain);
  60                 if (strlen(type->typ_name) == strlen(name) &&
  61                     strcmp(type->typ_name, name) == 0) {
  62                         spin_unlock(&obd_types_lock);
  63                         return type;
  64                 }
  65         }
  66         spin_unlock(&obd_types_lock);
  67         return NULL;
  68 }
  69
  70 struct obd_type *class_get_type(char *name)
  71 {
  72         struct obd_type *type = class_search_type(name);
  73
  74 #ifdef CONFIG_KMOD
  75         if (!type) {
  76                 if (!request_module(name)) {
  77                         CDEBUG(D_INFO, "Loaded module '%s'\n", name);
  78                         type = class_search_type(name);
  79                 } else
  80                         CDEBUG(D_INFO, "Can't load module '%s'\n", name);
  81         }
  82 #endif
  83         if (type)
  84                 try_module_get(type->typ_ops->o_owner);
  85         return type;
  86 }
  87
  88 void class_put_type(struct obd_type *type)
  89 {
  90         LASSERT(type);
  91         module_put(type->typ_ops->o_owner);
  92 }
  93
  94 int class_register_type(struct obd_ops *ops, struct lprocfs_vars *vars,
  95                         char *name)
  96 {
  97         struct obd_type *type;
  98         int rc = 0;
  99         ENTRY;
 100
 101         LASSERT(strnlen(name, 1024) < 1024);    /* sanity check */
 102
 103         if (class_search_type(name)) {
 104                 CDEBUG(D_IOCTL, "Type %s already registered\n", name);
 105                 RETURN(-EEXIST);
 106         }
 107
 108         rc = -ENOMEM;
 109         OBD_ALLOC(type, sizeof(*type));
 110         if (type == NULL)
 111                 RETURN(rc);
 112
 113         OBD_ALLOC(type->typ_ops, sizeof(*type->typ_ops));
 114         OBD_ALLOC(type->typ_name, strlen(name) + 1);
 115         if (type->typ_ops == NULL || type->typ_name == NULL)
 116                 GOTO (failed, rc);
 117
 118         *(type->typ_ops) = *ops;
 119         strcpy(type->typ_name, name);
 120
 121 #ifdef LPROCFS
 122         type->typ_procroot = lprocfs_register(type->typ_name, proc_lustre_root,
 123                                               vars, type);
 124 #endif
 125         if (IS_ERR(type->typ_procroot)) {
 126                 rc = PTR_ERR(type->typ_procroot);
 127                 type->typ_procroot = NULL;
 128                 GOTO (failed, rc);
 129         }
 130
 131         spin_lock(&obd_types_lock);
 132         list_add(&type->typ_chain, &obd_types);
 133         spin_unlock(&obd_types_lock);
 134
 135         RETURN (0);
 136
 137  failed:
 138         if (type->typ_name != NULL)
 139                 OBD_FREE(type->typ_name, strlen(name) + 1);
 140         if (type->typ_ops != NULL)
 141                 OBD_FREE (type->typ_ops, sizeof (*type->typ_ops));
 142         OBD_FREE(type, sizeof(*type));
 143         RETURN(rc);
 144 }
 145
 146 int class_unregister_type(char *name)
 147 {
 148         struct obd_type *type = class_search_type(name);
 149         ENTRY;
 150
 151         if (!type) {
 152                 CERROR("unknown obd type\n");
 153                 RETURN(-EINVAL);
 154         }
 155
 156         if (type->typ_refcnt) {
 157                 CERROR("type %s has refcount (%d)\n", name, type->typ_refcnt);
 158                 /* This is a bad situation, let's make the best of it */
 159                 /* Remove ops, but leave the name for debugging */
 160                 OBD_FREE(type->typ_ops, sizeof(*type->typ_ops));
 161                 RETURN(-EBUSY);
 162         }
 163
 164         if (type->typ_procroot) {
 165                 lprocfs_remove(type->typ_procroot);
 166                 type->typ_procroot = NULL;
 167         }
 168
 169         spin_lock(&obd_types_lock);
 170         list_del(&type->typ_chain);
 171         spin_unlock(&obd_types_lock);
 172         OBD_FREE(type->typ_name, strlen(name) + 1);
 173         if (type->typ_ops != NULL)
 174                 OBD_FREE(type->typ_ops, sizeof(*type->typ_ops));
 175         OBD_FREE(type, sizeof(*type));
 176         RETURN(0);
 177 } /* class_unregister_type */
 178
 179 struct obd_device *class_newdev(int *dev)
 180 {
 181         struct obd_device *result = NULL;
 182         int i;
 183
 184         for (i = 0 ; i < MAX_OBD_DEVICES ; i++) {
 185                 struct obd_device *obd = &obd_dev[i];
 186                 if (!obd->obd_type) {
 187                         result = obd;
 188                         if (dev)
 189                                 *dev = i;
 190                         break;
 191                 }
 192         }
 193         return result;
 194 }
 195
 196 int class_name2dev(char *name)
 197 {
 198         int i;
 199
 200         if (!name)
 201                 return -1;
 202
 203         for (i = 0; i < MAX_OBD_DEVICES; i++) {
 204                 struct obd_device *obd = &obd_dev[i];
 205                 if (obd->obd_name && strcmp(name, obd->obd_name) == 0)
 206                         return i;
 207         }
 208
 209         return -1;
 210 }
 211
 212 struct obd_device *class_name2obd(char *name)
 213 {
 214         int dev = class_name2dev(name);
 215         if (dev < 0)
 216                 return NULL;
 217         return &obd_dev[dev];
 218 }
 219
 220 int class_uuid2dev(struct obd_uuid *uuid)
 221 {
 222         int i;
 223
 224         for (i = 0; i < MAX_OBD_DEVICES; i++) {
 225                 struct obd_device *obd = &obd_dev[i];
 226                 if (obd_uuid_equals(uuid, &obd->obd_uuid))
 227                         return i;
 228         }
 229
 230         return -1;
 231 }
 232
 233 struct obd_device *class_uuid2obd(struct obd_uuid *uuid)
 234 {
 235         int dev = class_uuid2dev(uuid);
 236         if (dev < 0)
 237                 return NULL;
 238         return &obd_dev[dev];
 239 }
 240
 241 /* Search for a client OBD connected to tgt_uuid.  If grp_uuid is
 242    specified, then only the client with that uuid is returned,
 243    otherwise any client connected to the tgt is returned. */
 244 struct obd_device * class_find_client_obd(struct obd_uuid *tgt_uuid,
 245                                           char * typ_name,
 246                                           struct obd_uuid *grp_uuid)
 247 {
 248         int i;
 249
 250         for (i = 0; i < MAX_OBD_DEVICES; i++) {
 251                 struct obd_device *obd = &obd_dev[i];
 252                 if (obd->obd_type == NULL)
 253                         continue;
 254                 if ((strncmp(obd->obd_type->typ_name, typ_name,
 255                              strlen(typ_name)) == 0)) {
 256                         struct client_obd *cli = &obd->u.cli;
 257                         struct obd_import *imp = cli->cl_import;
 258                         if (obd_uuid_equals(tgt_uuid, &imp->imp_target_uuid) &&
 259                             ((grp_uuid)? obd_uuid_equals(grp_uuid,
 260                                                          &obd->obd_uuid) : 1)) {
 261                                 return obd;
 262                         }
 263                 }
 264         }
 265
 266         return NULL;
 267 }
 268
 269 /* Iterate the obd_device list looking devices have grp_uuid. Start
 270    searching at *next, and if a device is found, the next index to look
 271    it is saved in *next. If next is NULL, then the first matching device
 272    will always be returned. */
 273 struct obd_device * class_devices_in_group(struct obd_uuid *grp_uuid, int *next)
 274 {
 275         int i;
 276         if (next == NULL)
 277                 i = 0;
 278         else if (*next >= 0 && *next < MAX_OBD_DEVICES)
 279                 i = *next;
 280         else
 281                 return NULL;
 282
 283         for (; i < MAX_OBD_DEVICES; i++) {
 284                 struct obd_device *obd = &obd_dev[i];
 285                 if (obd->obd_type == NULL)
 286                         continue;
 287                 if (obd_uuid_equals(grp_uuid, &obd->obd_uuid)) {
 288                         if (next != NULL)
 289                                 *next = i+1;
 290                         return obd;
 291                 }
 292         }
 293
 294         return NULL;
 295 }
 296
 297
 298 void obd_cleanup_caches(void)
 299 {
 300         int rc;
 301         ENTRY;
 302         if (obdo_cachep) {
 303                 rc = kmem_cache_destroy(obdo_cachep);
 304                 if (rc)
 305                         CERROR("Cannot destory ll_obdo_cache\n");
 306                 obdo_cachep = NULL;
 307         }
 308         if (import_cachep) {
 309                 rc = kmem_cache_destroy(import_cachep);
 310                 if (rc)
 311                         CERROR("Cannot destory ll_import_cache\n");
 312                 import_cachep = NULL;
 313         }
 314         EXIT;
 315 }
 316
 317 int obd_init_caches(void)
 318 {
 319         ENTRY;
 320         LASSERT(obdo_cachep == NULL);
 321         obdo_cachep = kmem_cache_create("ll_obdo_cache", sizeof(struct obdo),
 322                                         0, 0, NULL, NULL);
 323         if (!obdo_cachep)
 324                 GOTO(out, -ENOMEM);
 325
 326         LASSERT(import_cachep == NULL);
 327         import_cachep = kmem_cache_create("ll_import_cache",
 328                                           sizeof(struct obd_import),
 329                                           0, 0, NULL, NULL);
 330         if (!import_cachep)
 331                 GOTO(out, -ENOMEM);
 332
 333         RETURN(0);
 334  out:
 335         obd_cleanup_caches();
 336         RETURN(-ENOMEM);
 337
 338 }
 339
 340 /* map connection to client */
 341 struct obd_export *class_conn2export(struct lustre_handle *conn)
 342 {
 343         struct obd_export *export;
 344         ENTRY;
 345
 346         if (!conn) {
 347                 CDEBUG(D_CACHE, "looking for null handle\n");
 348                 RETURN(NULL);
 349         }
 350
 351         if (conn->cookie == -1) {  /* this means assign a new connection */
 352                 CDEBUG(D_CACHE, "want a new connection\n");
 353                 RETURN(NULL);
 354         }
 355
 356         CDEBUG(D_IOCTL, "looking for export cookie "LPX64"\n", conn->cookie);
 357         export = class_handle2object(conn->cookie);
 358         RETURN(export);
 359 }
 360
 361 struct obd_device *class_exp2obd(struct obd_export *exp)
 362 {
 363         if (exp)
 364                 return exp->exp_obd;
 365         return NULL;
 366 }
 367
 368 struct obd_device *class_conn2obd(struct lustre_handle *conn)
 369 {
 370         struct obd_export *export;
 371         export = class_conn2export(conn);
 372         if (export) {
 373                 struct obd_device *obd = export->exp_obd;
 374                 class_export_put(export);
 375                 return obd;
 376         }
 377         return NULL;
 378 }
 379
 380 struct obd_import *class_exp2cliimp(struct obd_export *exp)
 381 {
 382         struct obd_device *obd = exp->exp_obd;
 383         if (obd == NULL)
 384                 return NULL;
 385         return obd->u.cli.cl_import;
 386 }
 387
 388 struct obd_import *class_conn2cliimp(struct lustre_handle *conn)
 389 {
 390         struct obd_device *obd = class_conn2obd(conn);
 391         if (obd == NULL)
 392                 return NULL;
 393         return obd->u.cli.cl_import;
 394 }
 395
 396 /* Export management functions */
 397 static void export_handle_addref(void *export)
 398 {
 399         class_export_get(export);
 400 }
 401
 402 void __class_export_put(struct obd_export *exp)
 403 {
 404         if (atomic_dec_and_test(&exp->exp_refcount)) {
 405                 struct obd_device *obd = exp->exp_obd;
 406                 CDEBUG(D_IOCTL, "destroying export %p/%s\n", exp,
 407                        exp->exp_client_uuid.uuid);
 408
 409                 LASSERT(obd != NULL);
 410
 411                 /* "Local" exports (lctl, LOV->{mdc,osc}) have no connection. */
 412                 if (exp->exp_connection)
 413                         ptlrpc_put_connection_superhack(exp->exp_connection);
 414
 415                 LASSERT(list_empty(&exp->exp_outstanding_replies));
 416                 LASSERT(list_empty(&exp->exp_handle.h_link));
 417                 obd_destroy_export(exp);
 418
 419                 OBD_FREE(exp, sizeof(*exp));
 420                 if (obd->obd_set_up) {
 421                         atomic_dec(&obd->obd_refcount);
 422                         wake_up(&obd->obd_refcount_waitq);
 423                 }
 424         }
 425 }
 426
 427 /* Creates a new export, adds it to the hash table, and returns a
 428  * pointer to it. The refcount is 2: one for the hash reference, and
 429  * one for the pointer returned by this function. */
 430 struct obd_export *class_new_export(struct obd_device *obd)
 431 {
 432         struct obd_export *export;
 433
 434         OBD_ALLOC(export, sizeof(*export));
 435         if (!export) {
 436                 CERROR("no memory! (minor %d)\n", obd->obd_minor);
 437                 return NULL;
 438         }
 439
 440         export->exp_conn_cnt = 0;
 441         atomic_set(&export->exp_refcount, 2);
 442         export->exp_obd = obd;
 443         INIT_LIST_HEAD(&export->exp_outstanding_replies);
 444         /* XXX this should be in LDLM init */
 445         INIT_LIST_HEAD(&export->exp_ldlm_data.led_held_locks);
 446
 447         INIT_LIST_HEAD(&export->exp_handle.h_link);
 448         class_handle_hash(&export->exp_handle, export_handle_addref);
 449         spin_lock_init(&export->exp_lock);
 450
 451         spin_lock(&obd->obd_dev_lock);
 452         LASSERT(!obd->obd_stopping); /* shouldn't happen, but might race */
 453         atomic_inc(&obd->obd_refcount);
 454         list_add(&export->exp_obd_chain, &export->exp_obd->obd_exports);
 455         export->exp_obd->obd_num_exports++;
 456         spin_unlock(&obd->obd_dev_lock);
 457         obd_init_export(export);
 458         return export;
 459 }
 460
 461 void class_unlink_export(struct obd_export *exp)
 462 {
 463         class_handle_unhash(&exp->exp_handle);
 464
 465         spin_lock(&exp->exp_obd->obd_dev_lock);
 466         list_del_init(&exp->exp_obd_chain);
 467         exp->exp_obd->obd_num_exports--;
 468         spin_unlock(&exp->exp_obd->obd_dev_lock);
 469
 470         class_export_put(exp);
 471 }
 472
 473 /* Import management functions */
 474 static void import_handle_addref(void *import)
 475 {
 476         class_import_get(import);
 477 }
 478
 479 struct obd_import *class_import_get(struct obd_import *import)
 480 {
 481         atomic_inc(&import->imp_refcount);
 482         CDEBUG(D_IOCTL, "import %p refcount=%d\n", import,
 483                atomic_read(&import->imp_refcount));
 484         return import;
 485 }
 486
 487 void class_import_put(struct obd_import *import)
 488 {
 489         ENTRY;
 490
 491         CDEBUG(D_IOCTL, "import %p refcount=%d\n", import,
 492                atomic_read(&import->imp_refcount) - 1);
 493
 494         LASSERT(atomic_read(&import->imp_refcount) > 0);
 495         LASSERT(atomic_read(&import->imp_refcount) < 0x5a5a5a);
 496         if (!atomic_dec_and_test(&import->imp_refcount)) {
 497                 EXIT;
 498                 return;
 499         }
 500
 501         CDEBUG(D_IOCTL, "destroying import %p\n", import);
 502
 503         ptlrpc_put_connection_superhack(import->imp_connection);
 504
 505         LASSERT(list_empty(&import->imp_handle.h_link));
 506         OBD_FREE(import, sizeof(*import));
 507         EXIT;
 508 }
 509
 510 struct obd_import *class_new_import(void)
 511 {
 512         struct obd_import *imp;
 513
 514         OBD_ALLOC(imp, sizeof(*imp));
 515         if (imp == NULL)
 516                 return NULL;
 517
 518         INIT_LIST_HEAD(&imp->imp_replay_list);
 519         INIT_LIST_HEAD(&imp->imp_sending_list);
 520         INIT_LIST_HEAD(&imp->imp_delayed_list);
 521         spin_lock_init(&imp->imp_lock);
 522         imp->imp_conn_cnt = 0;
 523         imp->imp_max_transno = 0;
 524         imp->imp_peer_committed_transno = 0;
 525         imp->imp_state = LUSTRE_IMP_NEW;
 526         init_waitqueue_head(&imp->imp_recovery_waitq);
 527
 528         atomic_set(&imp->imp_refcount, 2);
 529         atomic_set(&imp->imp_replay_inflight, 0);
 530         INIT_LIST_HEAD(&imp->imp_handle.h_link);
 531         class_handle_hash(&imp->imp_handle, import_handle_addref);
 532
 533         return imp;
 534 }
 535
 536 void class_destroy_import(struct obd_import *import)
 537 {
 538         LASSERT(import != NULL);
 539         LASSERT((unsigned long)import != 0x5a5a5a5a);
 540
 541         class_handle_unhash(&import->imp_handle);
 542
 543         /* Abort any inflight DLM requests and NULL out their (about to be
 544          * freed) import. */
 545         /* Invalidate all requests on import, would be better to call
 546            ptlrpc_set_import_active(imp, 0); */
 547         import->imp_generation++;
 548         ptlrpc_abort_inflight_superhack(import);
 549
 550         class_import_put(import);
 551 }
 552
 553 /* A connection defines an export context in which preallocation can
 554    be managed. This releases the export pointer reference, and returns
 555    the export handle, so the export refcount is 1 when this function
 556    returns. */
 557 int class_connect(struct lustre_handle *conn, struct obd_device *obd,
 558                   struct obd_uuid *cluuid)
 559 {
 560         struct obd_export *export;
 561         LASSERT(conn != NULL);
 562         LASSERT(obd != NULL);
 563         LASSERT(cluuid != NULL);
 564         ENTRY;
 565
 566         export = class_new_export(obd);
 567         if (export == NULL)
 568                 RETURN(-ENOMEM);
 569
 570         conn->cookie = export->exp_handle.h_cookie;
 571         memcpy(&export->exp_client_uuid, cluuid,
 572                sizeof(export->exp_client_uuid));
 573         class_export_put(export);
 574
 575         CDEBUG(D_IOCTL, "connect: client %s, cookie "LPX64"\n",
 576                cluuid->uuid, conn->cookie);
 577         RETURN(0);
 578 }
 579
 580 /* This function removes two references from the export: one for the
 581  * hash entry and one for the export pointer passed in.  The export
 582  * pointer passed to this function is destroyed should not be used
 583  * again. */
 584 int class_disconnect(struct obd_export *export, int flags)
 585 {
 586         ENTRY;
 587
 588         if (export == NULL) {
 589                 fixme();
 590                 CDEBUG(D_IOCTL, "attempting to free NULL export %p\n", export);
 591                 RETURN(-EINVAL);
 592         }
 593
 594         /* XXX this shouldn't have to be here, but double-disconnect will crash
 595          * otherwise, and sometimes double-disconnect happens.  abort_recovery,
 596          * for example. */
 597         if (list_empty(&export->exp_handle.h_link))
 598                 RETURN(0);
 599
 600         CDEBUG(D_IOCTL, "disconnect: cookie "LPX64"\n",
 601                export->exp_handle.h_cookie);
 602
 603         class_unlink_export(export);
 604         class_export_put(export);
 605         RETURN(0);
 606 }
 607
 608 void class_disconnect_exports(struct obd_device *obd, int flags)
 609 {
 610         int rc;
 611         struct list_head *tmp, *n, work_list;
 612         struct lustre_handle fake_conn;
 613         struct obd_export *fake_exp, *exp;
 614         ENTRY;
 615
 616         /* Move all of the exports from obd_exports to a work list, en masse. */
 617         spin_lock(&obd->obd_dev_lock);
 618         list_add(&work_list, &obd->obd_exports);
 619         list_del_init(&obd->obd_exports);
 620         spin_unlock(&obd->obd_dev_lock);
 621
 622         CDEBUG(D_HA, "OBD device %d (%p) has exports, "
 623                "disconnecting them\n", obd->obd_minor, obd);
 624         list_for_each_safe(tmp, n, &work_list) {
 625                 exp = list_entry(tmp, struct obd_export, exp_obd_chain);
 626                 class_export_get(exp);
 627
 628                 if (obd_uuid_equals(&exp->exp_client_uuid,
 629                                     &exp->exp_obd->obd_uuid)) {
 630                         CDEBUG(D_HA,
 631                                "exp %p export uuid == obd uuid, don't discon\n",
 632                                exp);
 633                         class_export_put(exp);
 634                         continue;
 635                 }
 636
 637                 fake_conn.cookie = exp->exp_handle.h_cookie;
 638                 fake_exp = class_conn2export(&fake_conn);
 639                 if (!fake_exp) {
 640                         class_export_put(exp);
 641                         continue;
 642                 }
 643                 rc = obd_disconnect(fake_exp, flags);
 644                 class_export_put(exp);
 645                 if (rc) {
 646                         CDEBUG(D_HA, "disconnecting export %p failed: %d\n",
 647                                exp, rc);
 648                 } else {
 649                         CDEBUG(D_HA, "export %p disconnected\n", exp);
 650                 }
 651         }
 652         EXIT;
 653 }
 654
 655 int oig_init(struct obd_io_group **oig_out)
 656 {
 657         struct obd_io_group *oig;
 658         ENTRY;
 659
 660         OBD_ALLOC(oig, sizeof(*oig));
 661         if (oig == NULL)
 662                 RETURN(-ENOMEM);
 663
 664         spin_lock_init(&oig->oig_lock);
 665         oig->oig_rc = 0;
 666         oig->oig_pending = 0;
 667         atomic_set(&oig->oig_refcount, 1);
 668         init_waitqueue_head(&oig->oig_waitq);
 669         INIT_LIST_HEAD(&oig->oig_occ_list);
 670
 671         *oig_out = oig;
 672         RETURN(0);
 673 };
 674
 675 static inline void oig_grab(struct obd_io_group *oig)
 676 {
 677         atomic_inc(&oig->oig_refcount);
 678 }
 679 void oig_release(struct obd_io_group *oig)
 680 {
 681         if (atomic_dec_and_test(&oig->oig_refcount))
 682                 OBD_FREE(oig, sizeof(*oig));
 683 }
 684
 685 void oig_add_one(struct obd_io_group *oig,
 686                   struct oig_callback_context *occ)
 687 {
 688         unsigned long flags;
 689         CDEBUG(D_CACHE, "oig %p ready to roll\n", oig);
 690         spin_lock_irqsave(&oig->oig_lock, flags);
 691         oig->oig_pending++;
 692         if (occ != NULL)
 693                 list_add_tail(&occ->occ_oig_item, &oig->oig_occ_list);
 694         spin_unlock_irqrestore(&oig->oig_lock, flags);
 695         oig_grab(oig);
 696 }
 697
 698 void oig_complete_one(struct obd_io_group *oig,
 699                       struct oig_callback_context *occ, int rc)
 700 {
 701         unsigned long flags;
 702         wait_queue_head_t *wake = NULL;
 703         int old_rc;
 704
 705         spin_lock_irqsave(&oig->oig_lock, flags);
 706
 707         if (occ != NULL)
 708                 list_del_init(&occ->occ_oig_item);
 709
 710         old_rc = oig->oig_rc;
 711         if (oig->oig_rc == 0 && rc != 0)
 712                 oig->oig_rc = rc;
 713
 714         if (--oig->oig_pending <= 0)
 715                 wake = &oig->oig_waitq;
 716
 717         spin_unlock_irqrestore(&oig->oig_lock, flags);
 718
 719         CDEBUG(D_CACHE, "oig %p completed, rc %d -> %d via %d, %d now "
 720                         "pending (racey)\n", oig, old_rc, oig->oig_rc, rc,
 721                         oig->oig_pending);
 722         if (wake)
 723                 wake_up(wake);
 724         oig_release(oig);
 725 }
 726
 727 static int oig_done(struct obd_io_group *oig)
 728 {
 729         unsigned long flags;
 730         int rc = 0;
 731         spin_lock_irqsave(&oig->oig_lock, flags);
 732         if (oig->oig_pending <= 0)
 733                 rc = 1;
 734         spin_unlock_irqrestore(&oig->oig_lock, flags);
 735         return rc;
 736 }
 737
 738 static void interrupted_oig(void *data)
 739 {
 740         struct obd_io_group *oig = data;
 741         struct list_head *pos;
 742         struct oig_callback_context *occ;
 743         unsigned long flags;
 744
 745         spin_lock_irqsave(&oig->oig_lock, flags);
 746         list_for_each(pos, &oig->oig_occ_list) {
 747                 occ = list_entry(pos, struct oig_callback_context,
 748                                  occ_oig_item);
 749                 occ->occ_interrupted(occ);
 750         }
 751         spin_unlock_irqrestore(&oig->oig_lock, flags);
 752 }
 753
 754 int oig_wait(struct obd_io_group *oig)
 755 {
 756         struct l_wait_info lwi = LWI_INTR(interrupted_oig, oig);
 757         int rc;
 758
 759         CDEBUG(D_CACHE, "waiting for oig %p\n", oig);
 760
 761         do {
 762                 rc = l_wait_event(oig->oig_waitq, oig_done(oig), &lwi);
 763                 LASSERTF(rc == 0 || rc == -EINTR, "rc: %d\n", rc);
 764                 /* we can't continue until the oig has emptied and stopped
 765                  * referencing state that the caller will free upon return */
 766                 if (rc == -EINTR)
 767                         lwi = (struct l_wait_info){ 0, };
 768         } while (rc == -EINTR);
 769
 770         LASSERTF(oig->oig_pending == 0,
 771                  "exiting oig_wait(oig = %p) with %d pending\n", oig,
 772                  oig->oig_pending);
 773
 774         CDEBUG(D_CACHE, "done waiting on oig %p rc %d\n", oig, oig->oig_rc);
 775         return oig->oig_rc;
 776 }