drivers/staging/lustre/lustre/obdclass/lu_object.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2012, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/obdclass/lu_object.c
  37  *
  38  * Lustre Object.
  39  * These are the only exported functions, they provide some generic
  40  * infrastructure for managing object devices
  41  *
  42  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  43  */
  44
  45 #define DEBUG_SUBSYSTEM S_CLASS
  46
  47 #include "../../include/linux/libcfs/libcfs.h"
  48
  49 # include <linux/module.h>
  50
  51 /* hash_long() */
  52 #include "../../include/linux/libcfs/libcfs_hash.h"
  53 #include "../include/obd_class.h"
  54 #include "../include/obd_support.h"
  55 #include "../include/lustre_disk.h"
  56 #include "../include/lustre_fid.h"
  57 #include "../include/lu_object.h"
  58 #include "../include/lu_ref.h"
  59 #include <linux/list.h>
  60
  61 static void lu_object_free(const struct lu_env *env, struct lu_object *o);
  62
  63 /**
  64  * Decrease reference counter on object. If last reference is freed, return
  65  * object to the cache, unless lu_object_is_dying(o) holds. In the latter
  66  * case, free object immediately.
  67  */
  68 void lu_object_put(const struct lu_env *env, struct lu_object *o)
  69 {
  70         struct lu_site_bkt_data *bkt;
  71         struct lu_object_header *top;
  72         struct lu_site    *site;
  73         struct lu_object        *orig;
  74         struct cfs_hash_bd          bd;
  75         const struct lu_fid     *fid;
  76
  77         top  = o->lo_header;
  78         site = o->lo_dev->ld_site;
  79         orig = o;
  80
  81         /*
  82          * till we have full fids-on-OST implemented anonymous objects
  83          * are possible in OSP. such an object isn't listed in the site
  84          * so we should not remove it from the site.
  85          */
  86         fid = lu_object_fid(o);
  87         if (fid_is_zero(fid)) {
  88                 LASSERT(top->loh_hash.next == NULL
  89                         && top->loh_hash.pprev == NULL);
  90                 LASSERT(list_empty(&top->loh_lru));
  91                 if (!atomic_dec_and_test(&top->loh_ref))
  92                         return;
  93                 list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
  94                         if (o->lo_ops->loo_object_release != NULL)
  95                                 o->lo_ops->loo_object_release(env, o);
  96                 }
  97                 lu_object_free(env, orig);
  98                 return;
  99         }
 100
 101         cfs_hash_bd_get(site->ls_obj_hash, &top->loh_fid, &bd);
 102         bkt = cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
 103
 104         if (!cfs_hash_bd_dec_and_lock(site->ls_obj_hash, &bd, &top->loh_ref)) {
 105                 if (lu_object_is_dying(top)) {
 106
 107                         /*
 108                          * somebody may be waiting for this, currently only
 109                          * used for cl_object, see cl_object_put_last().
 110                          */
 111                         wake_up_all(&bkt->lsb_marche_funebre);
 112                 }
 113                 return;
 114         }
 115
 116         LASSERT(bkt->lsb_busy > 0);
 117         bkt->lsb_busy--;
 118         /*
 119          * When last reference is released, iterate over object
 120          * layers, and notify them that object is no longer busy.
 121          */
 122         list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
 123                 if (o->lo_ops->loo_object_release != NULL)
 124                         o->lo_ops->loo_object_release(env, o);
 125         }
 126
 127         if (!lu_object_is_dying(top)) {
 128                 LASSERT(list_empty(&top->loh_lru));
 129                 list_add_tail(&top->loh_lru, &bkt->lsb_lru);
 130                 cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
 131                 return;
 132         }
 133
 134         /*
 135          * If object is dying (will not be cached), removed it
 136          * from hash table and LRU.
 137          *
 138          * This is done with hash table and LRU lists locked. As the only
 139          * way to acquire first reference to previously unreferenced
 140          * object is through hash-table lookup (lu_object_find()),
 141          * or LRU scanning (lu_site_purge()), that are done under hash-table
 142          * and LRU lock, no race with concurrent object lookup is possible
 143          * and we can safely destroy object below.
 144          */
 145         if (!test_and_set_bit(LU_OBJECT_UNHASHED, &top->loh_flags))
 146                 cfs_hash_bd_del_locked(site->ls_obj_hash, &bd, &top->loh_hash);
 147         cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
 148         /*
 149          * Object was already removed from hash and lru above, can
 150          * kill it.
 151          */
 152         lu_object_free(env, orig);
 153 }
 154 EXPORT_SYMBOL(lu_object_put);
 155
 156 /**
 157  * Put object and don't keep in cache. This is temporary solution for
 158  * multi-site objects when its layering is not constant.
 159  */
 160 void lu_object_put_nocache(const struct lu_env *env, struct lu_object *o)
 161 {
 162         set_bit(LU_OBJECT_HEARD_BANSHEE, &o->lo_header->loh_flags);
 163         return lu_object_put(env, o);
 164 }
 165 EXPORT_SYMBOL(lu_object_put_nocache);
 166
 167 /**
 168  * Kill the object and take it out of LRU cache.
 169  * Currently used by client code for layout change.
 170  */
 171 void lu_object_unhash(const struct lu_env *env, struct lu_object *o)
 172 {
 173         struct lu_object_header *top;
 174
 175         top = o->lo_header;
 176         set_bit(LU_OBJECT_HEARD_BANSHEE, &top->loh_flags);
 177         if (!test_and_set_bit(LU_OBJECT_UNHASHED, &top->loh_flags)) {
 178                 struct cfs_hash *obj_hash = o->lo_dev->ld_site->ls_obj_hash;
 179                 struct cfs_hash_bd bd;
 180
 181                 cfs_hash_bd_get_and_lock(obj_hash, &top->loh_fid, &bd, 1);
 182                 list_del_init(&top->loh_lru);
 183                 cfs_hash_bd_del_locked(obj_hash, &bd, &top->loh_hash);
 184                 cfs_hash_bd_unlock(obj_hash, &bd, 1);
 185         }
 186 }
 187 EXPORT_SYMBOL(lu_object_unhash);
 188
 189 /**
 190  * Allocate new object.
 191  *
 192  * This follows object creation protocol, described in the comment within
 193  * struct lu_device_operations definition.
 194  */
 195 static struct lu_object *lu_object_alloc(const struct lu_env *env,
 196                                          struct lu_device *dev,
 197                                          const struct lu_fid *f,
 198                                          const struct lu_object_conf *conf)
 199 {
 200         struct lu_object *scan;
 201         struct lu_object *top;
 202         struct list_head *layers;
 203         unsigned int init_mask = 0;
 204         unsigned int init_flag;
 205         int clean;
 206         int result;
 207
 208         /*
 209          * Create top-level object slice. This will also create
 210          * lu_object_header.
 211          */
 212         top = dev->ld_ops->ldo_object_alloc(env, NULL, dev);
 213         if (top == NULL)
 214                 return ERR_PTR(-ENOMEM);
 215         if (IS_ERR(top))
 216                 return top;
 217         /*
 218          * This is the only place where object fid is assigned. It's constant
 219          * after this point.
 220          */
 221         top->lo_header->loh_fid = *f;
 222         layers = &top->lo_header->loh_layers;
 223
 224         do {
 225                 /*
 226                  * Call ->loo_object_init() repeatedly, until no more new
 227                  * object slices are created.
 228                  */
 229                 clean = 1;
 230                 init_flag = 1;
 231                 list_for_each_entry(scan, layers, lo_linkage) {
 232                         if (init_mask & init_flag)
 233                                 goto next;
 234                         clean = 0;
 235                         scan->lo_header = top->lo_header;
 236                         result = scan->lo_ops->loo_object_init(env, scan, conf);
 237                         if (result != 0) {
 238                                 lu_object_free(env, top);
 239                                 return ERR_PTR(result);
 240                         }
 241                         init_mask |= init_flag;
 242 next:
 243                         init_flag <<= 1;
 244                 }
 245         } while (!clean);
 246
 247         list_for_each_entry_reverse(scan, layers, lo_linkage) {
 248                 if (scan->lo_ops->loo_object_start != NULL) {
 249                         result = scan->lo_ops->loo_object_start(env, scan);
 250                         if (result != 0) {
 251                                 lu_object_free(env, top);
 252                                 return ERR_PTR(result);
 253                         }
 254                 }
 255         }
 256
 257         lprocfs_counter_incr(dev->ld_site->ls_stats, LU_SS_CREATED);
 258         return top;
 259 }
 260
 261 /**
 262  * Free an object.
 263  */
 264 static void lu_object_free(const struct lu_env *env, struct lu_object *o)
 265 {
 266         struct lu_site_bkt_data *bkt;
 267         struct lu_site    *site;
 268         struct lu_object        *scan;
 269         struct list_head              *layers;
 270         struct list_head               splice;
 271
 272         site   = o->lo_dev->ld_site;
 273         layers = &o->lo_header->loh_layers;
 274         bkt    = lu_site_bkt_from_fid(site, &o->lo_header->loh_fid);
 275         /*
 276          * First call ->loo_object_delete() method to release all resources.
 277          */
 278         list_for_each_entry_reverse(scan, layers, lo_linkage) {
 279                 if (scan->lo_ops->loo_object_delete != NULL)
 280                         scan->lo_ops->loo_object_delete(env, scan);
 281         }
 282
 283         /*
 284          * Then, splice object layers into stand-alone list, and call
 285          * ->loo_object_free() on all layers to free memory. Splice is
 286          * necessary, because lu_object_header is freed together with the
 287          * top-level slice.
 288          */
 289         INIT_LIST_HEAD(&splice);
 290         list_splice_init(layers, &splice);
 291         while (!list_empty(&splice)) {
 292                 /*
 293                  * Free layers in bottom-to-top order, so that object header
 294                  * lives as long as possible and ->loo_object_free() methods
 295                  * can look at its contents.
 296                  */
 297                 o = container_of0(splice.prev, struct lu_object, lo_linkage);
 298                 list_del_init(&o->lo_linkage);
 299                 LASSERT(o->lo_ops->loo_object_free != NULL);
 300                 o->lo_ops->loo_object_free(env, o);
 301         }
 302
 303         if (waitqueue_active(&bkt->lsb_marche_funebre))
 304                 wake_up_all(&bkt->lsb_marche_funebre);
 305 }
 306
 307 /**
 308  * Free \a nr objects from the cold end of the site LRU list.
 309  */
 310 int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr)
 311 {
 312         struct lu_object_header *h;
 313         struct lu_object_header *temp;
 314         struct lu_site_bkt_data *bkt;
 315         struct cfs_hash_bd          bd;
 316         struct cfs_hash_bd          bd2;
 317         struct list_head               dispose;
 318         int                   did_sth;
 319         int                   start;
 320         int                   count;
 321         int                   bnr;
 322         int                   i;
 323
 324         if (OBD_FAIL_CHECK(OBD_FAIL_OBD_NO_LRU))
 325                 return 0;
 326
 327         INIT_LIST_HEAD(&dispose);
 328         /*
 329          * Under LRU list lock, scan LRU list and move unreferenced objects to
 330          * the dispose list, removing them from LRU and hash table.
 331          */
 332         start = s->ls_purge_start;
 333         bnr = (nr == ~0) ? -1 : nr / CFS_HASH_NBKT(s->ls_obj_hash) + 1;
 334  again:
 335         did_sth = 0;
 336         cfs_hash_for_each_bucket(s->ls_obj_hash, &bd, i) {
 337                 if (i < start)
 338                         continue;
 339                 count = bnr;
 340                 cfs_hash_bd_lock(s->ls_obj_hash, &bd, 1);
 341                 bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, &bd);
 342
 343                 list_for_each_entry_safe(h, temp, &bkt->lsb_lru, loh_lru) {
 344                         LASSERT(atomic_read(&h->loh_ref) == 0);
 345
 346                         cfs_hash_bd_get(s->ls_obj_hash, &h->loh_fid, &bd2);
 347                         LASSERT(bd.bd_bucket == bd2.bd_bucket);
 348
 349                         cfs_hash_bd_del_locked(s->ls_obj_hash,
 350                                                &bd2, &h->loh_hash);
 351                         list_move(&h->loh_lru, &dispose);
 352                         if (did_sth == 0)
 353                                 did_sth = 1;
 354
 355                         if (nr != ~0 && --nr == 0)
 356                                 break;
 357
 358                         if (count > 0 && --count == 0)
 359                                 break;
 360
 361                 }
 362                 cfs_hash_bd_unlock(s->ls_obj_hash, &bd, 1);
 363                 cond_resched();
 364                 /*
 365                  * Free everything on the dispose list. This is safe against
 366                  * races due to the reasons described in lu_object_put().
 367                  */
 368                 while (!list_empty(&dispose)) {
 369                         h = container_of0(dispose.next,
 370                                           struct lu_object_header, loh_lru);
 371                         list_del_init(&h->loh_lru);
 372                         lu_object_free(env, lu_object_top(h));
 373                         lprocfs_counter_incr(s->ls_stats, LU_SS_LRU_PURGED);
 374                 }
 375
 376                 if (nr == 0)
 377                         break;
 378         }
 379
 380         if (nr != 0 && did_sth && start != 0) {
 381                 start = 0; /* restart from the first bucket */
 382                 goto again;
 383         }
 384         /* race on s->ls_purge_start, but nobody cares */
 385         s->ls_purge_start = i % CFS_HASH_NBKT(s->ls_obj_hash);
 386
 387         return nr;
 388 }
 389 EXPORT_SYMBOL(lu_site_purge);
 390
 391 /*
 392  * Object printing.
 393  *
 394  * Code below has to jump through certain loops to output object description
 395  * into libcfs_debug_msg-based log. The problem is that lu_object_print()
 396  * composes object description from strings that are parts of _lines_ of
 397  * output (i.e., strings that are not terminated by newline). This doesn't fit
 398  * very well into libcfs_debug_msg() interface that assumes that each message
 399  * supplied to it is a self-contained output line.
 400  *
 401  * To work around this, strings are collected in a temporary buffer
 402  * (implemented as a value of lu_cdebug_key key), until terminating newline
 403  * character is detected.
 404  *
 405  */
 406
 407 enum {
 408         /**
 409          * Maximal line size.
 410          *
 411          * XXX overflow is not handled correctly.
 412          */
 413         LU_CDEBUG_LINE = 512
 414 };
 415
 416 struct lu_cdebug_data {
 417         /**
 418          * Temporary buffer.
 419          */
 420         char lck_area[LU_CDEBUG_LINE];
 421 };
 422
 423 /* context key constructor/destructor: lu_global_key_init, lu_global_key_fini */
 424 LU_KEY_INIT_FINI(lu_global, struct lu_cdebug_data);
 425
 426 /**
 427  * Key, holding temporary buffer. This key is registered very early by
 428  * lu_global_init().
 429  */
 430 struct lu_context_key lu_global_key = {
 431         .lct_tags = LCT_MD_THREAD | LCT_DT_THREAD |
 432                     LCT_MG_THREAD | LCT_CL_THREAD | LCT_LOCAL,
 433         .lct_init = lu_global_key_init,
 434         .lct_fini = lu_global_key_fini
 435 };
 436
 437 /**
 438  * Printer function emitting messages through libcfs_debug_msg().
 439  */
 440 int lu_cdebug_printer(const struct lu_env *env,
 441                       void *cookie, const char *format, ...)
 442 {
 443         struct libcfs_debug_msg_data *msgdata = cookie;
 444         struct lu_cdebug_data   *key;
 445         int used;
 446         int complete;
 447         va_list args;
 448
 449         va_start(args, format);
 450
 451         key = lu_context_key_get(&env->le_ctx, &lu_global_key);
 452         LASSERT(key != NULL);
 453
 454         used = strlen(key->lck_area);
 455         complete = format[strlen(format) - 1] == '\n';
 456         /*
 457          * Append new chunk to the buffer.
 458          */
 459         vsnprintf(key->lck_area + used,
 460                   ARRAY_SIZE(key->lck_area) - used, format, args);
 461         if (complete) {
 462                 if (cfs_cdebug_show(msgdata->msg_mask, msgdata->msg_subsys))
 463                         libcfs_debug_msg(msgdata, "%s", key->lck_area);
 464                 key->lck_area[0] = 0;
 465         }
 466         va_end(args);
 467         return 0;
 468 }
 469 EXPORT_SYMBOL(lu_cdebug_printer);
 470
 471 /**
 472  * Print object header.
 473  */
 474 void lu_object_header_print(const struct lu_env *env, void *cookie,
 475                             lu_printer_t printer,
 476                             const struct lu_object_header *hdr)
 477 {
 478         (*printer)(env, cookie, "header@%p[%#lx, %d, "DFID"%s%s%s]",
 479                    hdr, hdr->loh_flags, atomic_read(&hdr->loh_ref),
 480                    PFID(&hdr->loh_fid),
 481                    hlist_unhashed(&hdr->loh_hash) ? "" : " hash",
 482                    list_empty((struct list_head *)&hdr->loh_lru) ? \
 483                    "" : " lru",
 484                    hdr->loh_attr & LOHA_EXISTS ? " exist":"");
 485 }
 486 EXPORT_SYMBOL(lu_object_header_print);
 487
 488 /**
 489  * Print human readable representation of the \a o to the \a printer.
 490  */
 491 void lu_object_print(const struct lu_env *env, void *cookie,
 492                      lu_printer_t printer, const struct lu_object *o)
 493 {
 494         static const char ruler[] = "........................................";
 495         struct lu_object_header *top;
 496         int depth = 4;
 497
 498         top = o->lo_header;
 499         lu_object_header_print(env, cookie, printer, top);
 500         (*printer)(env, cookie, "{\n");
 501
 502         list_for_each_entry(o, &top->loh_layers, lo_linkage) {
 503                 /*
 504                  * print `.' \a depth times followed by type name and address
 505                  */
 506                 (*printer)(env, cookie, "%*.*s%s@%p", depth, depth, ruler,
 507                            o->lo_dev->ld_type->ldt_name, o);
 508
 509                 if (o->lo_ops->loo_object_print != NULL)
 510                         (*o->lo_ops->loo_object_print)(env, cookie, printer, o);
 511
 512                 (*printer)(env, cookie, "\n");
 513         }
 514
 515         (*printer)(env, cookie, "} header@%p\n", top);
 516 }
 517 EXPORT_SYMBOL(lu_object_print);
 518
 519 /**
 520  * Check object consistency.
 521  */
 522 int lu_object_invariant(const struct lu_object *o)
 523 {
 524         struct lu_object_header *top;
 525
 526         top = o->lo_header;
 527         list_for_each_entry(o, &top->loh_layers, lo_linkage) {
 528                 if (o->lo_ops->loo_object_invariant != NULL &&
 529                     !o->lo_ops->loo_object_invariant(o))
 530                         return 0;
 531         }
 532         return 1;
 533 }
 534 EXPORT_SYMBOL(lu_object_invariant);
 535
 536 static struct lu_object *htable_lookup(struct lu_site *s,
 537                                        struct cfs_hash_bd *bd,
 538                                        const struct lu_fid *f,
 539                                        wait_queue_t *waiter,
 540                                        __u64 *version)
 541 {
 542         struct lu_site_bkt_data *bkt;
 543         struct lu_object_header *h;
 544         struct hlist_node       *hnode;
 545         __u64  ver = cfs_hash_bd_version_get(bd);
 546
 547         if (*version == ver)
 548                 return ERR_PTR(-ENOENT);
 549
 550         *version = ver;
 551         bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, bd);
 552         /* cfs_hash_bd_peek_locked is a somehow "internal" function
 553          * of cfs_hash, it doesn't add refcount on object. */
 554         hnode = cfs_hash_bd_peek_locked(s->ls_obj_hash, bd, (void *)f);
 555         if (hnode == NULL) {
 556                 lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_MISS);
 557                 return ERR_PTR(-ENOENT);
 558         }
 559
 560         h = container_of0(hnode, struct lu_object_header, loh_hash);
 561         if (likely(!lu_object_is_dying(h))) {
 562                 cfs_hash_get(s->ls_obj_hash, hnode);
 563                 lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_HIT);
 564                 list_del_init(&h->loh_lru);
 565                 return lu_object_top(h);
 566         }
 567
 568         /*
 569          * Lookup found an object being destroyed this object cannot be
 570          * returned (to assure that references to dying objects are eventually
 571          * drained), and moreover, lookup has to wait until object is freed.
 572          */
 573
 574         init_waitqueue_entry(waiter, current);
 575         add_wait_queue(&bkt->lsb_marche_funebre, waiter);
 576         set_current_state(TASK_UNINTERRUPTIBLE);
 577         lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_DEATH_RACE);
 578         return ERR_PTR(-EAGAIN);
 579 }
 580
 581 /**
 582  * Search cache for an object with the fid \a f. If such object is found,
 583  * return it. Otherwise, create new object, insert it into cache and return
 584  * it. In any case, additional reference is acquired on the returned object.
 585  */
 586 struct lu_object *lu_object_find(const struct lu_env *env,
 587                                  struct lu_device *dev, const struct lu_fid *f,
 588                                  const struct lu_object_conf *conf)
 589 {
 590         return lu_object_find_at(env, dev->ld_site->ls_top_dev, f, conf);
 591 }
 592 EXPORT_SYMBOL(lu_object_find);
 593
 594 static struct lu_object *lu_object_new(const struct lu_env *env,
 595                                        struct lu_device *dev,
 596                                        const struct lu_fid *f,
 597                                        const struct lu_object_conf *conf)
 598 {
 599         struct lu_object        *o;
 600         struct cfs_hash       *hs;
 601         struct cfs_hash_bd          bd;
 602         struct lu_site_bkt_data *bkt;
 603
 604         o = lu_object_alloc(env, dev, f, conf);
 605         if (unlikely(IS_ERR(o)))
 606                 return o;
 607
 608         hs = dev->ld_site->ls_obj_hash;
 609         cfs_hash_bd_get_and_lock(hs, (void *)f, &bd, 1);
 610         bkt = cfs_hash_bd_extra_get(hs, &bd);
 611         cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
 612         bkt->lsb_busy++;
 613         cfs_hash_bd_unlock(hs, &bd, 1);
 614         return o;
 615 }
 616
 617 /**
 618  * Core logic of lu_object_find*() functions.
 619  */
 620 static struct lu_object *lu_object_find_try(const struct lu_env *env,
 621                                             struct lu_device *dev,
 622                                             const struct lu_fid *f,
 623                                             const struct lu_object_conf *conf,
 624                                             wait_queue_t *waiter)
 625 {
 626         struct lu_object      *o;
 627         struct lu_object      *shadow;
 628         struct lu_site  *s;
 629         struct cfs_hash     *hs;
 630         struct cfs_hash_bd        bd;
 631         __u64             version = 0;
 632
 633         /*
 634          * This uses standard index maintenance protocol:
 635          *
 636          *     - search index under lock, and return object if found;
 637          *     - otherwise, unlock index, allocate new object;
 638          *     - lock index and search again;
 639          *     - if nothing is found (usual case), insert newly created
 640          *       object into index;
 641          *     - otherwise (race: other thread inserted object), free
 642          *       object just allocated.
 643          *     - unlock index;
 644          *     - return object.
 645          *
 646          * For "LOC_F_NEW" case, we are sure the object is new established.
 647          * It is unnecessary to perform lookup-alloc-lookup-insert, instead,
 648          * just alloc and insert directly.
 649          *
 650          * If dying object is found during index search, add @waiter to the
 651          * site wait-queue and return ERR_PTR(-EAGAIN).
 652          */
 653         if (conf != NULL && conf->loc_flags & LOC_F_NEW)
 654                 return lu_object_new(env, dev, f, conf);
 655
 656         s  = dev->ld_site;
 657         hs = s->ls_obj_hash;
 658         cfs_hash_bd_get_and_lock(hs, (void *)f, &bd, 1);
 659         o = htable_lookup(s, &bd, f, waiter, &version);
 660         cfs_hash_bd_unlock(hs, &bd, 1);
 661         if (!IS_ERR(o) || PTR_ERR(o) != -ENOENT)
 662                 return o;
 663
 664         /*
 665          * Allocate new object. This may result in rather complicated
 666          * operations, including fld queries, inode loading, etc.
 667          */
 668         o = lu_object_alloc(env, dev, f, conf);
 669         if (unlikely(IS_ERR(o)))
 670                 return o;
 671
 672         LASSERT(lu_fid_eq(lu_object_fid(o), f));
 673
 674         cfs_hash_bd_lock(hs, &bd, 1);
 675
 676         shadow = htable_lookup(s, &bd, f, waiter, &version);
 677         if (likely(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT)) {
 678                 struct lu_site_bkt_data *bkt;
 679
 680                 bkt = cfs_hash_bd_extra_get(hs, &bd);
 681                 cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
 682                 bkt->lsb_busy++;
 683                 cfs_hash_bd_unlock(hs, &bd, 1);
 684                 return o;
 685         }
 686
 687         lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_RACE);
 688         cfs_hash_bd_unlock(hs, &bd, 1);
 689         lu_object_free(env, o);
 690         return shadow;
 691 }
 692
 693 /**
 694  * Much like lu_object_find(), but top level device of object is specifically
 695  * \a dev rather than top level device of the site. This interface allows
 696  * objects of different "stacking" to be created within the same site.
 697  */
 698 struct lu_object *lu_object_find_at(const struct lu_env *env,
 699                                     struct lu_device *dev,
 700                                     const struct lu_fid *f,
 701                                     const struct lu_object_conf *conf)
 702 {
 703         struct lu_site_bkt_data *bkt;
 704         struct lu_object        *obj;
 705         wait_queue_t       wait;
 706
 707         while (1) {
 708                 obj = lu_object_find_try(env, dev, f, conf, &wait);
 709                 if (obj != ERR_PTR(-EAGAIN))
 710                         return obj;
 711                 /*
 712                  * lu_object_find_try() already added waiter into the
 713                  * wait queue.
 714                  */
 715                 schedule();
 716                 bkt = lu_site_bkt_from_fid(dev->ld_site, (void *)f);
 717                 remove_wait_queue(&bkt->lsb_marche_funebre, &wait);
 718         }
 719 }
 720 EXPORT_SYMBOL(lu_object_find_at);
 721
 722 /**
 723  * Find object with given fid, and return its slice belonging to given device.
 724  */
 725 struct lu_object *lu_object_find_slice(const struct lu_env *env,
 726                                        struct lu_device *dev,
 727                                        const struct lu_fid *f,
 728                                        const struct lu_object_conf *conf)
 729 {
 730         struct lu_object *top;
 731         struct lu_object *obj;
 732
 733         top = lu_object_find(env, dev, f, conf);
 734         if (!IS_ERR(top)) {
 735                 obj = lu_object_locate(top->lo_header, dev->ld_type);
 736                 if (obj == NULL)
 737                         lu_object_put(env, top);
 738         } else
 739                 obj = top;
 740         return obj;
 741 }
 742 EXPORT_SYMBOL(lu_object_find_slice);
 743
 744 /**
 745  * Global list of all device types.
 746  */
 747 static LIST_HEAD(lu_device_types);
 748
 749 int lu_device_type_init(struct lu_device_type *ldt)
 750 {
 751         int result = 0;
 752
 753         INIT_LIST_HEAD(&ldt->ldt_linkage);
 754         if (ldt->ldt_ops->ldto_init)
 755                 result = ldt->ldt_ops->ldto_init(ldt);
 756         if (result == 0)
 757                 list_add(&ldt->ldt_linkage, &lu_device_types);
 758         return result;
 759 }
 760 EXPORT_SYMBOL(lu_device_type_init);
 761
 762 void lu_device_type_fini(struct lu_device_type *ldt)
 763 {
 764         list_del_init(&ldt->ldt_linkage);
 765         if (ldt->ldt_ops->ldto_fini)
 766                 ldt->ldt_ops->ldto_fini(ldt);
 767 }
 768 EXPORT_SYMBOL(lu_device_type_fini);
 769
 770 void lu_types_stop(void)
 771 {
 772         struct lu_device_type *ldt;
 773
 774         list_for_each_entry(ldt, &lu_device_types, ldt_linkage) {
 775                 if (ldt->ldt_device_nr == 0 && ldt->ldt_ops->ldto_stop)
 776                         ldt->ldt_ops->ldto_stop(ldt);
 777         }
 778 }
 779 EXPORT_SYMBOL(lu_types_stop);
 780
 781 /**
 782  * Global list of all sites on this node
 783  */
 784 static LIST_HEAD(lu_sites);
 785 static DEFINE_MUTEX(lu_sites_guard);
 786
 787 /**
 788  * Global environment used by site shrinker.
 789  */
 790 static struct lu_env lu_shrink_env;
 791
 792 struct lu_site_print_arg {
 793         struct lu_env   *lsp_env;
 794         void        *lsp_cookie;
 795         lu_printer_t     lsp_printer;
 796 };
 797
 798 static int
 799 lu_site_obj_print(struct cfs_hash *hs, struct cfs_hash_bd *bd,
 800                   struct hlist_node *hnode, void *data)
 801 {
 802         struct lu_site_print_arg *arg = (struct lu_site_print_arg *)data;
 803         struct lu_object_header  *h;
 804
 805         h = hlist_entry(hnode, struct lu_object_header, loh_hash);
 806         if (!list_empty(&h->loh_layers)) {
 807                 const struct lu_object *o;
 808
 809                 o = lu_object_top(h);
 810                 lu_object_print(arg->lsp_env, arg->lsp_cookie,
 811                                 arg->lsp_printer, o);
 812         } else {
 813                 lu_object_header_print(arg->lsp_env, arg->lsp_cookie,
 814                                        arg->lsp_printer, h);
 815         }
 816         return 0;
 817 }
 818
 819 /**
 820  * Print all objects in \a s.
 821  */
 822 void lu_site_print(const struct lu_env *env, struct lu_site *s, void *cookie,
 823                    lu_printer_t printer)
 824 {
 825         struct lu_site_print_arg arg = {
 826                 .lsp_env     = (struct lu_env *)env,
 827                 .lsp_cookie  = cookie,
 828                 .lsp_printer = printer,
 829         };
 830
 831         cfs_hash_for_each(s->ls_obj_hash, lu_site_obj_print, &arg);
 832 }
 833 EXPORT_SYMBOL(lu_site_print);
 834
 835 enum {
 836         LU_CACHE_PERCENT_MAX     = 50,
 837         LU_CACHE_PERCENT_DEFAULT = 20
 838 };
 839
 840 static unsigned int lu_cache_percent = LU_CACHE_PERCENT_DEFAULT;
 841 module_param(lu_cache_percent, int, 0644);
 842 MODULE_PARM_DESC(lu_cache_percent, "Percentage of memory to be used as lu_object cache");
 843
 844 /**
 845  * Return desired hash table order.
 846  */
 847 static int lu_htable_order(void)
 848 {
 849         unsigned long cache_size;
 850         int bits;
 851
 852         /*
 853          * Calculate hash table size, assuming that we want reasonable
 854          * performance when 20% of total memory is occupied by cache of
 855          * lu_objects.
 856          *
 857          * Size of lu_object is (arbitrary) taken as 1K (together with inode).
 858          */
 859         cache_size = totalram_pages;
 860
 861 #if BITS_PER_LONG == 32
 862         /* limit hashtable size for lowmem systems to low RAM */
 863         if (cache_size > 1 << (30 - PAGE_CACHE_SHIFT))
 864                 cache_size = 1 << (30 - PAGE_CACHE_SHIFT) * 3 / 4;
 865 #endif
 866
 867         /* clear off unreasonable cache setting. */
 868         if (lu_cache_percent == 0 || lu_cache_percent > LU_CACHE_PERCENT_MAX) {
 869                 CWARN("obdclass: invalid lu_cache_percent: %u, it must be in"
 870                       " the range of (0, %u]. Will use default value: %u.\n",
 871                       lu_cache_percent, LU_CACHE_PERCENT_MAX,
 872                       LU_CACHE_PERCENT_DEFAULT);
 873
 874                 lu_cache_percent = LU_CACHE_PERCENT_DEFAULT;
 875         }
 876         cache_size = cache_size / 100 * lu_cache_percent *
 877                 (PAGE_CACHE_SIZE / 1024);
 878
 879         for (bits = 1; (1 << bits) < cache_size; ++bits) {
 880                 ;
 881         }
 882         return bits;
 883 }
 884
 885 static unsigned lu_obj_hop_hash(struct cfs_hash *hs,
 886                                 const void *key, unsigned mask)
 887 {
 888         struct lu_fid  *fid = (struct lu_fid *)key;
 889         __u32      hash;
 890
 891         hash = fid_flatten32(fid);
 892         hash += (hash >> 4) + (hash << 12); /* mixing oid and seq */
 893         hash = hash_long(hash, hs->hs_bkt_bits);
 894
 895         /* give me another random factor */
 896         hash -= hash_long((unsigned long)hs, fid_oid(fid) % 11 + 3);
 897
 898         hash <<= hs->hs_cur_bits - hs->hs_bkt_bits;
 899         hash |= (fid_seq(fid) + fid_oid(fid)) & (CFS_HASH_NBKT(hs) - 1);
 900
 901         return hash & mask;
 902 }
 903
 904 static void *lu_obj_hop_object(struct hlist_node *hnode)
 905 {
 906         return hlist_entry(hnode, struct lu_object_header, loh_hash);
 907 }
 908
 909 static void *lu_obj_hop_key(struct hlist_node *hnode)
 910 {
 911         struct lu_object_header *h;
 912
 913         h = hlist_entry(hnode, struct lu_object_header, loh_hash);
 914         return &h->loh_fid;
 915 }
 916
 917 static int lu_obj_hop_keycmp(const void *key, struct hlist_node *hnode)
 918 {
 919         struct lu_object_header *h;
 920
 921         h = hlist_entry(hnode, struct lu_object_header, loh_hash);
 922         return lu_fid_eq(&h->loh_fid, (struct lu_fid *)key);
 923 }
 924
 925 static void lu_obj_hop_get(struct cfs_hash *hs, struct hlist_node *hnode)
 926 {
 927         struct lu_object_header *h;
 928
 929         h = hlist_entry(hnode, struct lu_object_header, loh_hash);
 930         if (atomic_add_return(1, &h->loh_ref) == 1) {
 931                 struct lu_site_bkt_data *bkt;
 932                 struct cfs_hash_bd          bd;
 933
 934                 cfs_hash_bd_get(hs, &h->loh_fid, &bd);
 935                 bkt = cfs_hash_bd_extra_get(hs, &bd);
 936                 bkt->lsb_busy++;
 937         }
 938 }
 939
 940 static void lu_obj_hop_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
 941 {
 942         LBUG(); /* we should never called it */
 943 }
 944
 945 cfs_hash_ops_t lu_site_hash_ops = {
 946         .hs_hash        = lu_obj_hop_hash,
 947         .hs_key  = lu_obj_hop_key,
 948         .hs_keycmp      = lu_obj_hop_keycmp,
 949         .hs_object      = lu_obj_hop_object,
 950         .hs_get  = lu_obj_hop_get,
 951         .hs_put_locked  = lu_obj_hop_put_locked,
 952 };
 953
 954 void lu_dev_add_linkage(struct lu_site *s, struct lu_device *d)
 955 {
 956         spin_lock(&s->ls_ld_lock);
 957         if (list_empty(&d->ld_linkage))
 958                 list_add(&d->ld_linkage, &s->ls_ld_linkage);
 959         spin_unlock(&s->ls_ld_lock);
 960 }
 961 EXPORT_SYMBOL(lu_dev_add_linkage);
 962
 963 void lu_dev_del_linkage(struct lu_site *s, struct lu_device *d)
 964 {
 965         spin_lock(&s->ls_ld_lock);
 966         list_del_init(&d->ld_linkage);
 967         spin_unlock(&s->ls_ld_lock);
 968 }
 969 EXPORT_SYMBOL(lu_dev_del_linkage);
 970
 971 /**
 972  * Initialize site \a s, with \a d as the top level device.
 973  */
 974 #define LU_SITE_BITS_MIN    12
 975 #define LU_SITE_BITS_MAX    24
 976 /**
 977  * total 256 buckets, we don't want too many buckets because:
 978  * - consume too much memory
 979  * - avoid unbalanced LRU list
 980  */
 981 #define LU_SITE_BKT_BITS    8
 982
 983 int lu_site_init(struct lu_site *s, struct lu_device *top)
 984 {
 985         struct lu_site_bkt_data *bkt;
 986         struct cfs_hash_bd bd;
 987         char name[16];
 988         int bits;
 989         int i;
 990
 991         memset(s, 0, sizeof(*s));
 992         bits = lu_htable_order();
 993         snprintf(name, 16, "lu_site_%s", top->ld_type->ldt_name);
 994         for (bits = min(max(LU_SITE_BITS_MIN, bits), LU_SITE_BITS_MAX);
 995              bits >= LU_SITE_BITS_MIN; bits--) {
 996                 s->ls_obj_hash = cfs_hash_create(name, bits, bits,
 997                                                  bits - LU_SITE_BKT_BITS,
 998                                                  sizeof(*bkt), 0, 0,
 999                                                  &lu_site_hash_ops,
1000                                                  CFS_HASH_SPIN_BKTLOCK |
1001                                                  CFS_HASH_NO_ITEMREF |
1002                                                  CFS_HASH_DEPTH |
1003                                                  CFS_HASH_ASSERT_EMPTY);
1004                 if (s->ls_obj_hash != NULL)
1005                         break;
1006         }
1007
1008         if (s->ls_obj_hash == NULL) {
1009                 CERROR("failed to create lu_site hash with bits: %d\n", bits);
1010                 return -ENOMEM;
1011         }
1012
1013         cfs_hash_for_each_bucket(s->ls_obj_hash, &bd, i) {
1014                 bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, &bd);
1015                 INIT_LIST_HEAD(&bkt->lsb_lru);
1016                 init_waitqueue_head(&bkt->lsb_marche_funebre);
1017         }
1018
1019         s->ls_stats = lprocfs_alloc_stats(LU_SS_LAST_STAT, 0);
1020         if (s->ls_stats == NULL) {
1021                 cfs_hash_putref(s->ls_obj_hash);
1022                 s->ls_obj_hash = NULL;
1023                 return -ENOMEM;
1024         }
1025
1026         lprocfs_counter_init(s->ls_stats, LU_SS_CREATED,
1027                              0, "created", "created");
1028         lprocfs_counter_init(s->ls_stats, LU_SS_CACHE_HIT,
1029                              0, "cache_hit", "cache_hit");
1030         lprocfs_counter_init(s->ls_stats, LU_SS_CACHE_MISS,
1031                              0, "cache_miss", "cache_miss");
1032         lprocfs_counter_init(s->ls_stats, LU_SS_CACHE_RACE,
1033                              0, "cache_race", "cache_race");
1034         lprocfs_counter_init(s->ls_stats, LU_SS_CACHE_DEATH_RACE,
1035                              0, "cache_death_race", "cache_death_race");
1036         lprocfs_counter_init(s->ls_stats, LU_SS_LRU_PURGED,
1037                              0, "lru_purged", "lru_purged");
1038
1039         INIT_LIST_HEAD(&s->ls_linkage);
1040         s->ls_top_dev = top;
1041         top->ld_site = s;
1042         lu_device_get(top);
1043         lu_ref_add(&top->ld_reference, "site-top", s);
1044
1045         INIT_LIST_HEAD(&s->ls_ld_linkage);
1046         spin_lock_init(&s->ls_ld_lock);
1047
1048         lu_dev_add_linkage(s, top);
1049
1050         return 0;
1051 }
1052 EXPORT_SYMBOL(lu_site_init);
1053
1054 /**
1055  * Finalize \a s and release its resources.
1056  */
1057 void lu_site_fini(struct lu_site *s)
1058 {
1059         mutex_lock(&lu_sites_guard);
1060         list_del_init(&s->ls_linkage);
1061         mutex_unlock(&lu_sites_guard);
1062
1063         if (s->ls_obj_hash != NULL) {
1064                 cfs_hash_putref(s->ls_obj_hash);
1065                 s->ls_obj_hash = NULL;
1066         }
1067
1068         if (s->ls_top_dev != NULL) {
1069                 s->ls_top_dev->ld_site = NULL;
1070                 lu_ref_del(&s->ls_top_dev->ld_reference, "site-top", s);
1071                 lu_device_put(s->ls_top_dev);
1072                 s->ls_top_dev = NULL;
1073         }
1074
1075         if (s->ls_stats != NULL)
1076                 lprocfs_free_stats(&s->ls_stats);
1077 }
1078 EXPORT_SYMBOL(lu_site_fini);
1079
1080 /**
1081  * Called when initialization of stack for this site is completed.
1082  */
1083 int lu_site_init_finish(struct lu_site *s)
1084 {
1085         int result;
1086         mutex_lock(&lu_sites_guard);
1087         result = lu_context_refill(&lu_shrink_env.le_ctx);
1088         if (result == 0)
1089                 list_add(&s->ls_linkage, &lu_sites);
1090         mutex_unlock(&lu_sites_guard);
1091         return result;
1092 }
1093 EXPORT_SYMBOL(lu_site_init_finish);
1094
1095 /**
1096  * Acquire additional reference on device \a d
1097  */
1098 void lu_device_get(struct lu_device *d)
1099 {
1100         atomic_inc(&d->ld_ref);
1101 }
1102 EXPORT_SYMBOL(lu_device_get);
1103
1104 /**
1105  * Release reference on device \a d.
1106  */
1107 void lu_device_put(struct lu_device *d)
1108 {
1109         LASSERT(atomic_read(&d->ld_ref) > 0);
1110         atomic_dec(&d->ld_ref);
1111 }
1112 EXPORT_SYMBOL(lu_device_put);
1113
1114 /**
1115  * Initialize device \a d of type \a t.
1116  */
1117 int lu_device_init(struct lu_device *d, struct lu_device_type *t)
1118 {
1119         if (t->ldt_device_nr++ == 0 && t->ldt_ops->ldto_start != NULL)
1120                 t->ldt_ops->ldto_start(t);
1121         memset(d, 0, sizeof(*d));
1122         atomic_set(&d->ld_ref, 0);
1123         d->ld_type = t;
1124         lu_ref_init(&d->ld_reference);
1125         INIT_LIST_HEAD(&d->ld_linkage);
1126         return 0;
1127 }
1128 EXPORT_SYMBOL(lu_device_init);
1129
1130 /**
1131  * Finalize device \a d.
1132  */
1133 void lu_device_fini(struct lu_device *d)
1134 {
1135         struct lu_device_type *t;
1136
1137         t = d->ld_type;
1138         if (d->ld_obd != NULL) {
1139                 d->ld_obd->obd_lu_dev = NULL;
1140                 d->ld_obd = NULL;
1141         }
1142
1143         lu_ref_fini(&d->ld_reference);
1144         LASSERTF(atomic_read(&d->ld_ref) == 0,
1145                  "Refcount is %u\n", atomic_read(&d->ld_ref));
1146         LASSERT(t->ldt_device_nr > 0);
1147         if (--t->ldt_device_nr == 0 && t->ldt_ops->ldto_stop != NULL)
1148                 t->ldt_ops->ldto_stop(t);
1149 }
1150 EXPORT_SYMBOL(lu_device_fini);
1151
1152 /**
1153  * Initialize object \a o that is part of compound object \a h and was created
1154  * by device \a d.
1155  */
1156 int lu_object_init(struct lu_object *o, struct lu_object_header *h,
1157                    struct lu_device *d)
1158 {
1159         memset(o, 0, sizeof(*o));
1160         o->lo_header = h;
1161         o->lo_dev = d;
1162         lu_device_get(d);
1163         lu_ref_add_at(&d->ld_reference, &o->lo_dev_ref, "lu_object", o);
1164         INIT_LIST_HEAD(&o->lo_linkage);
1165
1166         return 0;
1167 }
1168 EXPORT_SYMBOL(lu_object_init);
1169
1170 /**
1171  * Finalize object and release its resources.
1172  */
1173 void lu_object_fini(struct lu_object *o)
1174 {
1175         struct lu_device *dev = o->lo_dev;
1176
1177         LASSERT(list_empty(&o->lo_linkage));
1178
1179         if (dev != NULL) {
1180                 lu_ref_del_at(&dev->ld_reference, &o->lo_dev_ref,
1181                               "lu_object", o);
1182                 lu_device_put(dev);
1183                 o->lo_dev = NULL;
1184         }
1185 }
1186 EXPORT_SYMBOL(lu_object_fini);
1187
1188 /**
1189  * Add object \a o as first layer of compound object \a h
1190  *
1191  * This is typically called by the ->ldo_object_alloc() method of top-level
1192  * device.
1193  */
1194 void lu_object_add_top(struct lu_object_header *h, struct lu_object *o)
1195 {
1196         list_move(&o->lo_linkage, &h->loh_layers);
1197 }
1198 EXPORT_SYMBOL(lu_object_add_top);
1199
1200 /**
1201  * Add object \a o as a layer of compound object, going after \a before.
1202  *
1203  * This is typically called by the ->ldo_object_alloc() method of \a
1204  * before->lo_dev.
1205  */
1206 void lu_object_add(struct lu_object *before, struct lu_object *o)
1207 {
1208         list_move(&o->lo_linkage, &before->lo_linkage);
1209 }
1210 EXPORT_SYMBOL(lu_object_add);
1211
1212 /**
1213  * Initialize compound object.
1214  */
1215 int lu_object_header_init(struct lu_object_header *h)
1216 {
1217         memset(h, 0, sizeof(*h));
1218         atomic_set(&h->loh_ref, 1);
1219         INIT_HLIST_NODE(&h->loh_hash);
1220         INIT_LIST_HEAD(&h->loh_lru);
1221         INIT_LIST_HEAD(&h->loh_layers);
1222         lu_ref_init(&h->loh_reference);
1223         return 0;
1224 }
1225 EXPORT_SYMBOL(lu_object_header_init);
1226
1227 /**
1228  * Finalize compound object.
1229  */
1230 void lu_object_header_fini(struct lu_object_header *h)
1231 {
1232         LASSERT(list_empty(&h->loh_layers));
1233         LASSERT(list_empty(&h->loh_lru));
1234         LASSERT(hlist_unhashed(&h->loh_hash));
1235         lu_ref_fini(&h->loh_reference);
1236 }
1237 EXPORT_SYMBOL(lu_object_header_fini);
1238
1239 /**
1240  * Given a compound object, find its slice, corresponding to the device type
1241  * \a dtype.
1242  */
1243 struct lu_object *lu_object_locate(struct lu_object_header *h,
1244                                    const struct lu_device_type *dtype)
1245 {
1246         struct lu_object *o;
1247
1248         list_for_each_entry(o, &h->loh_layers, lo_linkage) {
1249                 if (o->lo_dev->ld_type == dtype)
1250                         return o;
1251         }
1252         return NULL;
1253 }
1254 EXPORT_SYMBOL(lu_object_locate);
1255
1256
1257
1258 /**
1259  * Finalize and free devices in the device stack.
1260  *
1261  * Finalize device stack by purging object cache, and calling
1262  * lu_device_type_operations::ldto_device_fini() and
1263  * lu_device_type_operations::ldto_device_free() on all devices in the stack.
1264  */
1265 void lu_stack_fini(const struct lu_env *env, struct lu_device *top)
1266 {
1267         struct lu_site   *site = top->ld_site;
1268         struct lu_device *scan;
1269         struct lu_device *next;
1270
1271         lu_site_purge(env, site, ~0);
1272         for (scan = top; scan != NULL; scan = next) {
1273                 next = scan->ld_type->ldt_ops->ldto_device_fini(env, scan);
1274                 lu_ref_del(&scan->ld_reference, "lu-stack", &lu_site_init);
1275                 lu_device_put(scan);
1276         }
1277
1278         /* purge again. */
1279         lu_site_purge(env, site, ~0);
1280
1281         for (scan = top; scan != NULL; scan = next) {
1282                 const struct lu_device_type *ldt = scan->ld_type;
1283                 struct obd_type      *type;
1284
1285                 next = ldt->ldt_ops->ldto_device_free(env, scan);
1286                 type = ldt->ldt_obd_type;
1287                 if (type != NULL) {
1288                         type->typ_refcnt--;
1289                         class_put_type(type);
1290                 }
1291         }
1292 }
1293 EXPORT_SYMBOL(lu_stack_fini);
1294
1295 enum {
1296         /**
1297          * Maximal number of tld slots.
1298          */
1299         LU_CONTEXT_KEY_NR = 40
1300 };
1301
1302 static struct lu_context_key *lu_keys[LU_CONTEXT_KEY_NR] = { NULL, };
1303
1304 static DEFINE_SPINLOCK(lu_keys_guard);
1305
1306 /**
1307  * Global counter incremented whenever key is registered, unregistered,
1308  * revived or quiesced. This is used to void unnecessary calls to
1309  * lu_context_refill(). No locking is provided, as initialization and shutdown
1310  * are supposed to be externally serialized.
1311  */
1312 static unsigned key_set_version = 0;
1313
1314 /**
1315  * Register new key.
1316  */
1317 int lu_context_key_register(struct lu_context_key *key)
1318 {
1319         int result;
1320         int i;
1321
1322         LASSERT(key->lct_init != NULL);
1323         LASSERT(key->lct_fini != NULL);
1324         LASSERT(key->lct_tags != 0);
1325
1326         result = -ENFILE;
1327         spin_lock(&lu_keys_guard);
1328         for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
1329                 if (lu_keys[i] == NULL) {
1330                         key->lct_index = i;
1331                         atomic_set(&key->lct_used, 1);
1332                         lu_keys[i] = key;
1333                         lu_ref_init(&key->lct_reference);
1334                         result = 0;
1335                         ++key_set_version;
1336                         break;
1337                 }
1338         }
1339         spin_unlock(&lu_keys_guard);
1340         return result;
1341 }
1342 EXPORT_SYMBOL(lu_context_key_register);
1343
1344 static void key_fini(struct lu_context *ctx, int index)
1345 {
1346         if (ctx->lc_value != NULL && ctx->lc_value[index] != NULL) {
1347                 struct lu_context_key *key;
1348
1349                 key = lu_keys[index];
1350                 LASSERT(key != NULL);
1351                 LASSERT(key->lct_fini != NULL);
1352                 LASSERT(atomic_read(&key->lct_used) > 1);
1353
1354                 key->lct_fini(ctx, key, ctx->lc_value[index]);
1355                 lu_ref_del(&key->lct_reference, "ctx", ctx);
1356                 atomic_dec(&key->lct_used);
1357
1358                 if ((ctx->lc_tags & LCT_NOREF) == 0) {
1359 #ifdef CONFIG_MODULE_UNLOAD
1360                         LINVRNT(module_refcount(key->lct_owner) > 0);
1361 #endif
1362                         module_put(key->lct_owner);
1363                 }
1364                 ctx->lc_value[index] = NULL;
1365         }
1366 }
1367
1368 /**
1369  * Deregister key.
1370  */
1371 void lu_context_key_degister(struct lu_context_key *key)
1372 {
1373         LASSERT(atomic_read(&key->lct_used) >= 1);
1374         LINVRNT(0 <= key->lct_index && key->lct_index < ARRAY_SIZE(lu_keys));
1375
1376         lu_context_key_quiesce(key);
1377
1378         ++key_set_version;
1379         spin_lock(&lu_keys_guard);
1380         key_fini(&lu_shrink_env.le_ctx, key->lct_index);
1381         if (lu_keys[key->lct_index]) {
1382                 lu_keys[key->lct_index] = NULL;
1383                 lu_ref_fini(&key->lct_reference);
1384         }
1385         spin_unlock(&lu_keys_guard);
1386
1387         LASSERTF(atomic_read(&key->lct_used) == 1,
1388                  "key has instances: %d\n",
1389                  atomic_read(&key->lct_used));
1390 }
1391 EXPORT_SYMBOL(lu_context_key_degister);
1392
1393 /**
1394  * Register a number of keys. This has to be called after all keys have been
1395  * initialized by a call to LU_CONTEXT_KEY_INIT().
1396  */
1397 int lu_context_key_register_many(struct lu_context_key *k, ...)
1398 {
1399         struct lu_context_key *key = k;
1400         va_list args;
1401         int result;
1402
1403         va_start(args, k);
1404         do {
1405                 result = lu_context_key_register(key);
1406                 if (result)
1407                         break;
1408                 key = va_arg(args, struct lu_context_key *);
1409         } while (key != NULL);
1410         va_end(args);
1411
1412         if (result != 0) {
1413                 va_start(args, k);
1414                 while (k != key) {
1415                         lu_context_key_degister(k);
1416                         k = va_arg(args, struct lu_context_key *);
1417                 }
1418                 va_end(args);
1419         }
1420
1421         return result;
1422 }
1423 EXPORT_SYMBOL(lu_context_key_register_many);
1424
1425 /**
1426  * De-register a number of keys. This is a dual to
1427  * lu_context_key_register_many().
1428  */
1429 void lu_context_key_degister_many(struct lu_context_key *k, ...)
1430 {
1431         va_list args;
1432
1433         va_start(args, k);
1434         do {
1435                 lu_context_key_degister(k);
1436                 k = va_arg(args, struct lu_context_key*);
1437         } while (k != NULL);
1438         va_end(args);
1439 }
1440 EXPORT_SYMBOL(lu_context_key_degister_many);
1441
1442 /**
1443  * Revive a number of keys.
1444  */
1445 void lu_context_key_revive_many(struct lu_context_key *k, ...)
1446 {
1447         va_list args;
1448
1449         va_start(args, k);
1450         do {
1451                 lu_context_key_revive(k);
1452                 k = va_arg(args, struct lu_context_key*);
1453         } while (k != NULL);
1454         va_end(args);
1455 }
1456 EXPORT_SYMBOL(lu_context_key_revive_many);
1457
1458 /**
1459  * Quiescent a number of keys.
1460  */
1461 void lu_context_key_quiesce_many(struct lu_context_key *k, ...)
1462 {
1463         va_list args;
1464
1465         va_start(args, k);
1466         do {
1467                 lu_context_key_quiesce(k);
1468                 k = va_arg(args, struct lu_context_key*);
1469         } while (k != NULL);
1470         va_end(args);
1471 }
1472 EXPORT_SYMBOL(lu_context_key_quiesce_many);
1473
1474 /**
1475  * Return value associated with key \a key in context \a ctx.
1476  */
1477 void *lu_context_key_get(const struct lu_context *ctx,
1478                          const struct lu_context_key *key)
1479 {
1480         LINVRNT(ctx->lc_state == LCS_ENTERED);
1481         LINVRNT(0 <= key->lct_index && key->lct_index < ARRAY_SIZE(lu_keys));
1482         LASSERT(lu_keys[key->lct_index] == key);
1483         return ctx->lc_value[key->lct_index];
1484 }
1485 EXPORT_SYMBOL(lu_context_key_get);
1486
1487 /**
1488  * List of remembered contexts. XXX document me.
1489  */
1490 static LIST_HEAD(lu_context_remembered);
1491
1492 /**
1493  * Destroy \a key in all remembered contexts. This is used to destroy key
1494  * values in "shared" contexts (like service threads), when a module owning
1495  * the key is about to be unloaded.
1496  */
1497 void lu_context_key_quiesce(struct lu_context_key *key)
1498 {
1499         struct lu_context *ctx;
1500
1501         if (!(key->lct_tags & LCT_QUIESCENT)) {
1502                 /*
1503                  * XXX layering violation.
1504                  */
1505                 key->lct_tags |= LCT_QUIESCENT;
1506                 /*
1507                  * XXX memory barrier has to go here.
1508                  */
1509                 spin_lock(&lu_keys_guard);
1510                 list_for_each_entry(ctx, &lu_context_remembered,
1511                                         lc_remember)
1512                         key_fini(ctx, key->lct_index);
1513                 spin_unlock(&lu_keys_guard);
1514                 ++key_set_version;
1515         }
1516 }
1517 EXPORT_SYMBOL(lu_context_key_quiesce);
1518
1519 void lu_context_key_revive(struct lu_context_key *key)
1520 {
1521         key->lct_tags &= ~LCT_QUIESCENT;
1522         ++key_set_version;
1523 }
1524 EXPORT_SYMBOL(lu_context_key_revive);
1525
1526 static void keys_fini(struct lu_context *ctx)
1527 {
1528         int     i;
1529
1530         if (ctx->lc_value == NULL)
1531                 return;
1532
1533         for (i = 0; i < ARRAY_SIZE(lu_keys); ++i)
1534                 key_fini(ctx, i);
1535
1536         OBD_FREE(ctx->lc_value, ARRAY_SIZE(lu_keys) * sizeof(ctx->lc_value[0]));
1537         ctx->lc_value = NULL;
1538 }
1539
1540 static int keys_fill(struct lu_context *ctx)
1541 {
1542         int i;
1543
1544         LINVRNT(ctx->lc_value != NULL);
1545         for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
1546                 struct lu_context_key *key;
1547
1548                 key = lu_keys[i];
1549                 if (ctx->lc_value[i] == NULL && key != NULL &&
1550                     (key->lct_tags & ctx->lc_tags) &&
1551                     /*
1552                      * Don't create values for a LCT_QUIESCENT key, as this
1553                      * will pin module owning a key.
1554                      */
1555                     !(key->lct_tags & LCT_QUIESCENT)) {
1556                         void *value;
1557
1558                         LINVRNT(key->lct_init != NULL);
1559                         LINVRNT(key->lct_index == i);
1560
1561                         value = key->lct_init(ctx, key);
1562                         if (unlikely(IS_ERR(value)))
1563                                 return PTR_ERR(value);
1564
1565                         if (!(ctx->lc_tags & LCT_NOREF))
1566                                 try_module_get(key->lct_owner);
1567                         lu_ref_add_atomic(&key->lct_reference, "ctx", ctx);
1568                         atomic_inc(&key->lct_used);
1569                         /*
1570                          * This is the only place in the code, where an
1571                          * element of ctx->lc_value[] array is set to non-NULL
1572                          * value.
1573                          */
1574                         ctx->lc_value[i] = value;
1575                         if (key->lct_exit != NULL)
1576                                 ctx->lc_tags |= LCT_HAS_EXIT;
1577                 }
1578                 ctx->lc_version = key_set_version;
1579         }
1580         return 0;
1581 }
1582
1583 static int keys_init(struct lu_context *ctx)
1584 {
1585         OBD_ALLOC(ctx->lc_value,
1586                   ARRAY_SIZE(lu_keys) * sizeof(ctx->lc_value[0]));
1587         if (likely(ctx->lc_value != NULL))
1588                 return keys_fill(ctx);
1589
1590         return -ENOMEM;
1591 }
1592
1593 /**
1594  * Initialize context data-structure. Create values for all keys.
1595  */
1596 int lu_context_init(struct lu_context *ctx, __u32 tags)
1597 {
1598         int     rc;
1599
1600         memset(ctx, 0, sizeof(*ctx));
1601         ctx->lc_state = LCS_INITIALIZED;
1602         ctx->lc_tags = tags;
1603         if (tags & LCT_REMEMBER) {
1604                 spin_lock(&lu_keys_guard);
1605                 list_add(&ctx->lc_remember, &lu_context_remembered);
1606                 spin_unlock(&lu_keys_guard);
1607         } else {
1608                 INIT_LIST_HEAD(&ctx->lc_remember);
1609         }
1610
1611         rc = keys_init(ctx);
1612         if (rc != 0)
1613                 lu_context_fini(ctx);
1614
1615         return rc;
1616 }
1617 EXPORT_SYMBOL(lu_context_init);
1618
1619 /**
1620  * Finalize context data-structure. Destroy key values.
1621  */
1622 void lu_context_fini(struct lu_context *ctx)
1623 {
1624         LINVRNT(ctx->lc_state == LCS_INITIALIZED || ctx->lc_state == LCS_LEFT);
1625         ctx->lc_state = LCS_FINALIZED;
1626
1627         if ((ctx->lc_tags & LCT_REMEMBER) == 0) {
1628                 LASSERT(list_empty(&ctx->lc_remember));
1629                 keys_fini(ctx);
1630
1631         } else { /* could race with key degister */
1632                 spin_lock(&lu_keys_guard);
1633                 keys_fini(ctx);
1634                 list_del_init(&ctx->lc_remember);
1635                 spin_unlock(&lu_keys_guard);
1636         }
1637 }
1638 EXPORT_SYMBOL(lu_context_fini);
1639
1640 /**
1641  * Called before entering context.
1642  */
1643 void lu_context_enter(struct lu_context *ctx)
1644 {
1645         LINVRNT(ctx->lc_state == LCS_INITIALIZED || ctx->lc_state == LCS_LEFT);
1646         ctx->lc_state = LCS_ENTERED;
1647 }
1648 EXPORT_SYMBOL(lu_context_enter);
1649
1650 /**
1651  * Called after exiting from \a ctx
1652  */
1653 void lu_context_exit(struct lu_context *ctx)
1654 {
1655         int i;
1656
1657         LINVRNT(ctx->lc_state == LCS_ENTERED);
1658         ctx->lc_state = LCS_LEFT;
1659         if (ctx->lc_tags & LCT_HAS_EXIT && ctx->lc_value != NULL) {
1660                 for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
1661                         if (ctx->lc_value[i] != NULL) {
1662                                 struct lu_context_key *key;
1663
1664                                 key = lu_keys[i];
1665                                 LASSERT(key != NULL);
1666                                 if (key->lct_exit != NULL)
1667                                         key->lct_exit(ctx,
1668                                                       key, ctx->lc_value[i]);
1669                         }
1670                 }
1671         }
1672 }
1673 EXPORT_SYMBOL(lu_context_exit);
1674
1675 /**
1676  * Allocate for context all missing keys that were registered after context
1677  * creation. key_set_version is only changed in rare cases when modules
1678  * are loaded and removed.
1679  */
1680 int lu_context_refill(struct lu_context *ctx)
1681 {
1682         return likely(ctx->lc_version == key_set_version) ? 0 : keys_fill(ctx);
1683 }
1684 EXPORT_SYMBOL(lu_context_refill);
1685
1686 /**
1687  * lu_ctx_tags/lu_ses_tags will be updated if there are new types of
1688  * obd being added. Currently, this is only used on client side, specifically
1689  * for echo device client, for other stack (like ptlrpc threads), context are
1690  * predefined when the lu_device type are registered, during the module probe
1691  * phase.
1692  */
1693 __u32 lu_context_tags_default = 0;
1694 __u32 lu_session_tags_default = 0;
1695
1696 void lu_context_tags_update(__u32 tags)
1697 {
1698         spin_lock(&lu_keys_guard);
1699         lu_context_tags_default |= tags;
1700         key_set_version++;
1701         spin_unlock(&lu_keys_guard);
1702 }
1703 EXPORT_SYMBOL(lu_context_tags_update);
1704
1705 void lu_context_tags_clear(__u32 tags)
1706 {
1707         spin_lock(&lu_keys_guard);
1708         lu_context_tags_default &= ~tags;
1709         key_set_version++;
1710         spin_unlock(&lu_keys_guard);
1711 }
1712 EXPORT_SYMBOL(lu_context_tags_clear);
1713
1714 void lu_session_tags_update(__u32 tags)
1715 {
1716         spin_lock(&lu_keys_guard);
1717         lu_session_tags_default |= tags;
1718         key_set_version++;
1719         spin_unlock(&lu_keys_guard);
1720 }
1721 EXPORT_SYMBOL(lu_session_tags_update);
1722
1723 void lu_session_tags_clear(__u32 tags)
1724 {
1725         spin_lock(&lu_keys_guard);
1726         lu_session_tags_default &= ~tags;
1727         key_set_version++;
1728         spin_unlock(&lu_keys_guard);
1729 }
1730 EXPORT_SYMBOL(lu_session_tags_clear);
1731
1732 int lu_env_init(struct lu_env *env, __u32 tags)
1733 {
1734         int result;
1735
1736         env->le_ses = NULL;
1737         result = lu_context_init(&env->le_ctx, tags);
1738         if (likely(result == 0))
1739                 lu_context_enter(&env->le_ctx);
1740         return result;
1741 }
1742 EXPORT_SYMBOL(lu_env_init);
1743
1744 void lu_env_fini(struct lu_env *env)
1745 {
1746         lu_context_exit(&env->le_ctx);
1747         lu_context_fini(&env->le_ctx);
1748         env->le_ses = NULL;
1749 }
1750 EXPORT_SYMBOL(lu_env_fini);
1751
1752 int lu_env_refill(struct lu_env *env)
1753 {
1754         int result;
1755
1756         result = lu_context_refill(&env->le_ctx);
1757         if (result == 0 && env->le_ses != NULL)
1758                 result = lu_context_refill(env->le_ses);
1759         return result;
1760 }
1761 EXPORT_SYMBOL(lu_env_refill);
1762
1763 /**
1764  * Currently, this API will only be used by echo client.
1765  * Because echo client and normal lustre client will share
1766  * same cl_env cache. So echo client needs to refresh
1767  * the env context after it get one from the cache, especially
1768  * when normal client and echo client co-exist in the same client.
1769  */
1770 int lu_env_refill_by_tags(struct lu_env *env, __u32 ctags,
1771                           __u32 stags)
1772 {
1773         int    result;
1774
1775         if ((env->le_ctx.lc_tags & ctags) != ctags) {
1776                 env->le_ctx.lc_version = 0;
1777                 env->le_ctx.lc_tags |= ctags;
1778         }
1779
1780         if (env->le_ses && (env->le_ses->lc_tags & stags) != stags) {
1781                 env->le_ses->lc_version = 0;
1782                 env->le_ses->lc_tags |= stags;
1783         }
1784
1785         result = lu_env_refill(env);
1786
1787         return result;
1788 }
1789 EXPORT_SYMBOL(lu_env_refill_by_tags);
1790
1791
1792 typedef struct lu_site_stats{
1793         unsigned        lss_populated;
1794         unsigned        lss_max_search;
1795         unsigned        lss_total;
1796         unsigned        lss_busy;
1797 } lu_site_stats_t;
1798
1799 static void lu_site_stats_get(struct cfs_hash *hs,
1800                               lu_site_stats_t *stats, int populated)
1801 {
1802         struct cfs_hash_bd bd;
1803         int        i;
1804
1805         cfs_hash_for_each_bucket(hs, &bd, i) {
1806                 struct lu_site_bkt_data *bkt = cfs_hash_bd_extra_get(hs, &bd);
1807                 struct hlist_head       *hhead;
1808
1809                 cfs_hash_bd_lock(hs, &bd, 1);
1810                 stats->lss_busy  += bkt->lsb_busy;
1811                 stats->lss_total += cfs_hash_bd_count_get(&bd);
1812                 stats->lss_max_search = max((int)stats->lss_max_search,
1813                                             cfs_hash_bd_depmax_get(&bd));
1814                 if (!populated) {
1815                         cfs_hash_bd_unlock(hs, &bd, 1);
1816                         continue;
1817                 }
1818
1819                 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1820                         if (!hlist_empty(hhead))
1821                                 stats->lss_populated++;
1822                 }
1823                 cfs_hash_bd_unlock(hs, &bd, 1);
1824         }
1825 }
1826
1827
1828 /*
1829  * There exists a potential lock inversion deadlock scenario when using
1830  * Lustre on top of ZFS. This occurs between one of ZFS's
1831  * buf_hash_table.ht_lock's, and Lustre's lu_sites_guard lock. Essentially,
1832  * thread A will take the lu_sites_guard lock and sleep on the ht_lock,
1833  * while thread B will take the ht_lock and sleep on the lu_sites_guard
1834  * lock. Obviously neither thread will wake and drop their respective hold
1835  * on their lock.
1836  *
1837  * To prevent this from happening we must ensure the lu_sites_guard lock is
1838  * not taken while down this code path. ZFS reliably does not set the
1839  * __GFP_FS bit in its code paths, so this can be used to determine if it
1840  * is safe to take the lu_sites_guard lock.
1841  *
1842  * Ideally we should accurately return the remaining number of cached
1843  * objects without taking the  lu_sites_guard lock, but this is not
1844  * possible in the current implementation.
1845  */
1846 static unsigned long lu_cache_shrink_count(struct shrinker *sk,
1847                                            struct shrink_control *sc)
1848 {
1849         lu_site_stats_t stats;
1850         struct lu_site *s;
1851         struct lu_site *tmp;
1852         unsigned long cached = 0;
1853
1854         if (!(sc->gfp_mask & __GFP_FS))
1855                 return 0;
1856
1857         mutex_lock(&lu_sites_guard);
1858         list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
1859                 memset(&stats, 0, sizeof(stats));
1860                 lu_site_stats_get(s->ls_obj_hash, &stats, 0);
1861                 cached += stats.lss_total - stats.lss_busy;
1862         }
1863         mutex_unlock(&lu_sites_guard);
1864
1865         cached = (cached / 100) * sysctl_vfs_cache_pressure;
1866         CDEBUG(D_INODE, "%ld objects cached\n", cached);
1867         return cached;
1868 }
1869
1870 static unsigned long lu_cache_shrink_scan(struct shrinker *sk,
1871                                           struct shrink_control *sc)
1872 {
1873         struct lu_site *s;
1874         struct lu_site *tmp;
1875         unsigned long remain = sc->nr_to_scan, freed = 0;
1876         LIST_HEAD(splice);
1877
1878         if (!(sc->gfp_mask & __GFP_FS))
1879                 /* We must not take the lu_sites_guard lock when
1880                  * __GFP_FS is *not* set because of the deadlock
1881                  * possibility detailed above. Additionally,
1882                  * since we cannot determine the number of
1883                  * objects in the cache without taking this
1884                  * lock, we're in a particularly tough spot. As
1885                  * a result, we'll just lie and say our cache is
1886                  * empty. This _should_ be ok, as we can't
1887                  * reclaim objects when __GFP_FS is *not* set
1888                  * anyways.
1889                  */
1890                 return SHRINK_STOP;
1891
1892         mutex_lock(&lu_sites_guard);
1893         list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
1894                 freed = lu_site_purge(&lu_shrink_env, s, remain);
1895                 remain -= freed;
1896                 /*
1897                  * Move just shrunk site to the tail of site list to
1898                  * assure shrinking fairness.
1899                  */
1900                 list_move_tail(&s->ls_linkage, &splice);
1901         }
1902         list_splice(&splice, lu_sites.prev);
1903         mutex_unlock(&lu_sites_guard);
1904
1905         return sc->nr_to_scan - remain;
1906 }
1907
1908 /*
1909  * Debugging stuff.
1910  */
1911
1912 /**
1913  * Environment to be used in debugger, contains all tags.
1914  */
1915 struct lu_env lu_debugging_env;
1916
1917 /**
1918  * Debugging printer function using printk().
1919  */
1920 int lu_printk_printer(const struct lu_env *env,
1921                       void *unused, const char *format, ...)
1922 {
1923         va_list args;
1924
1925         va_start(args, format);
1926         vprintk(format, args);
1927         va_end(args);
1928         return 0;
1929 }
1930
1931 static struct shrinker lu_site_shrinker = {
1932         .count_objects  = lu_cache_shrink_count,
1933         .scan_objects   = lu_cache_shrink_scan,
1934         .seeks          = DEFAULT_SEEKS,
1935 };
1936
1937 /**
1938  * Initialization of global lu_* data.
1939  */
1940 int lu_global_init(void)
1941 {
1942         int result;
1943
1944         CDEBUG(D_INFO, "Lustre LU module (%p).\n", &lu_keys);
1945
1946         result = lu_ref_global_init();
1947         if (result != 0)
1948                 return result;
1949
1950         LU_CONTEXT_KEY_INIT(&lu_global_key);
1951         result = lu_context_key_register(&lu_global_key);
1952         if (result != 0)
1953                 return result;
1954
1955         /*
1956          * At this level, we don't know what tags are needed, so allocate them
1957          * conservatively. This should not be too bad, because this
1958          * environment is global.
1959          */
1960         mutex_lock(&lu_sites_guard);
1961         result = lu_env_init(&lu_shrink_env, LCT_SHRINKER);
1962         mutex_unlock(&lu_sites_guard);
1963         if (result != 0)
1964                 return result;
1965
1966         /*
1967          * seeks estimation: 3 seeks to read a record from oi, one to read
1968          * inode, one for ea. Unfortunately setting this high value results in
1969          * lu_object/inode cache consuming all the memory.
1970          */
1971         register_shrinker(&lu_site_shrinker);
1972
1973         return result;
1974 }
1975
1976 /**
1977  * Dual to lu_global_init().
1978  */
1979 void lu_global_fini(void)
1980 {
1981         unregister_shrinker(&lu_site_shrinker);
1982         lu_context_key_degister(&lu_global_key);
1983
1984         /*
1985          * Tear shrinker environment down _after_ de-registering
1986          * lu_global_key, because the latter has a value in the former.
1987          */
1988         mutex_lock(&lu_sites_guard);
1989         lu_env_fini(&lu_shrink_env);
1990         mutex_unlock(&lu_sites_guard);
1991
1992         lu_ref_global_fini();
1993 }
1994
1995 static __u32 ls_stats_read(struct lprocfs_stats *stats, int idx)
1996 {
1997 #if defined (CONFIG_PROC_FS)
1998         struct lprocfs_counter ret;
1999
2000         lprocfs_stats_collect(stats, idx, &ret);
2001         return (__u32)ret.lc_count;
2002 #else
2003         return 0;
2004 #endif
2005 }
2006
2007 /**
2008  * Output site statistical counters into a buffer. Suitable for
2009  * lprocfs_rd_*()-style functions.
2010  */
2011 int lu_site_stats_print(const struct lu_site *s, struct seq_file *m)
2012 {
2013         lu_site_stats_t stats;
2014
2015         memset(&stats, 0, sizeof(stats));
2016         lu_site_stats_get(s->ls_obj_hash, &stats, 1);
2017
2018         return seq_printf(m, "%d/%d %d/%d %d %d %d %d %d %d %d\n",
2019                         stats.lss_busy,
2020                         stats.lss_total,
2021                         stats.lss_populated,
2022                         CFS_HASH_NHLIST(s->ls_obj_hash),
2023                         stats.lss_max_search,
2024                         ls_stats_read(s->ls_stats, LU_SS_CREATED),
2025                         ls_stats_read(s->ls_stats, LU_SS_CACHE_HIT),
2026                         ls_stats_read(s->ls_stats, LU_SS_CACHE_MISS),
2027                         ls_stats_read(s->ls_stats, LU_SS_CACHE_RACE),
2028                         ls_stats_read(s->ls_stats, LU_SS_CACHE_DEATH_RACE),
2029                         ls_stats_read(s->ls_stats, LU_SS_LRU_PURGED));
2030 }
2031 EXPORT_SYMBOL(lu_site_stats_print);
2032
2033 /**
2034  * Helper function to initialize a number of kmem slab caches at once.
2035  */
2036 int lu_kmem_init(struct lu_kmem_descr *caches)
2037 {
2038         int result;
2039         struct lu_kmem_descr *iter = caches;
2040
2041         for (result = 0; iter->ckd_cache != NULL; ++iter) {
2042                 *iter->ckd_cache = kmem_cache_create(iter->ckd_name,
2043                                                         iter->ckd_size,
2044                                                         0, 0, NULL);
2045                 if (*iter->ckd_cache == NULL) {
2046                         result = -ENOMEM;
2047                         /* free all previously allocated caches */
2048                         lu_kmem_fini(caches);
2049                         break;
2050                 }
2051         }
2052         return result;
2053 }
2054 EXPORT_SYMBOL(lu_kmem_init);
2055
2056 /**
2057  * Helper function to finalize a number of kmem slab cached at once. Dual to
2058  * lu_kmem_init().
2059  */
2060 void lu_kmem_fini(struct lu_kmem_descr *caches)
2061 {
2062         for (; caches->ckd_cache != NULL; ++caches) {
2063                 if (*caches->ckd_cache != NULL) {
2064                         kmem_cache_destroy(*caches->ckd_cache);
2065                         *caches->ckd_cache = NULL;
2066                 }
2067         }
2068 }
2069 EXPORT_SYMBOL(lu_kmem_fini);
2070
2071 /**
2072  * Temporary solution to be able to assign fid in ->do_create()
2073  * till we have fully-functional OST fids
2074  */
2075 void lu_object_assign_fid(const struct lu_env *env, struct lu_object *o,
2076                           const struct lu_fid *fid)
2077 {
2078         struct lu_site          *s = o->lo_dev->ld_site;
2079         struct lu_fid           *old = &o->lo_header->loh_fid;
2080         struct lu_site_bkt_data *bkt;
2081         struct lu_object        *shadow;
2082         wait_queue_t             waiter;
2083         struct cfs_hash         *hs;
2084         struct cfs_hash_bd       bd;
2085         __u64                    version = 0;
2086
2087         LASSERT(fid_is_zero(old));
2088
2089         hs = s->ls_obj_hash;
2090         cfs_hash_bd_get_and_lock(hs, (void *)fid, &bd, 1);
2091         shadow = htable_lookup(s, &bd, fid, &waiter, &version);
2092         /* supposed to be unique */
2093         LASSERT(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT);
2094         *old = *fid;
2095         bkt = cfs_hash_bd_extra_get(hs, &bd);
2096         cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
2097         bkt->lsb_busy++;
2098         cfs_hash_bd_unlock(hs, &bd, 1);
2099 }
2100 EXPORT_SYMBOL(lu_object_assign_fid);
2101
2102 /**
2103  * allocates object with 0 (non-assigned) fid
2104  * XXX: temporary solution to be able to assign fid in ->do_create()
2105  *      till we have fully-functional OST fids
2106  */
2107 struct lu_object *lu_object_anon(const struct lu_env *env,
2108                                  struct lu_device *dev,
2109                                  const struct lu_object_conf *conf)
2110 {
2111         struct lu_fid     fid;
2112         struct lu_object *o;
2113
2114         fid_zero(&fid);
2115         o = lu_object_alloc(env, dev, &fid, conf);
2116
2117         return o;
2118 }
2119 EXPORT_SYMBOL(lu_object_anon);
2120
2121 struct lu_buf LU_BUF_NULL = {
2122         .lb_buf = NULL,
2123         .lb_len = 0
2124 };
2125 EXPORT_SYMBOL(LU_BUF_NULL);
2126
2127 void lu_buf_free(struct lu_buf *buf)
2128 {
2129         LASSERT(buf);
2130         if (buf->lb_buf) {
2131                 LASSERT(buf->lb_len > 0);
2132                 OBD_FREE_LARGE(buf->lb_buf, buf->lb_len);
2133                 buf->lb_buf = NULL;
2134                 buf->lb_len = 0;
2135         }
2136 }
2137 EXPORT_SYMBOL(lu_buf_free);
2138
2139 void lu_buf_alloc(struct lu_buf *buf, int size)
2140 {
2141         LASSERT(buf);
2142         LASSERT(buf->lb_buf == NULL);
2143         LASSERT(buf->lb_len == 0);
2144         OBD_ALLOC_LARGE(buf->lb_buf, size);
2145         if (likely(buf->lb_buf))
2146                 buf->lb_len = size;
2147 }
2148 EXPORT_SYMBOL(lu_buf_alloc);
2149
2150 void lu_buf_realloc(struct lu_buf *buf, int size)
2151 {
2152         lu_buf_free(buf);
2153         lu_buf_alloc(buf, size);
2154 }
2155 EXPORT_SYMBOL(lu_buf_realloc);
2156
2157 struct lu_buf *lu_buf_check_and_alloc(struct lu_buf *buf, int len)
2158 {
2159         if (buf->lb_buf == NULL && buf->lb_len == 0)
2160                 lu_buf_alloc(buf, len);
2161
2162         if ((len > buf->lb_len) && (buf->lb_buf != NULL))
2163                 lu_buf_realloc(buf, len);
2164
2165         return buf;
2166 }
2167 EXPORT_SYMBOL(lu_buf_check_and_alloc);
2168
2169 /**
2170  * Increase the size of the \a buf.
2171  * preserves old data in buffer
2172  * old buffer remains unchanged on error
2173  * \retval 0 or -ENOMEM
2174  */
2175 int lu_buf_check_and_grow(struct lu_buf *buf, int len)
2176 {
2177         char *ptr;
2178
2179         if (len <= buf->lb_len)
2180                 return 0;
2181
2182         OBD_ALLOC_LARGE(ptr, len);
2183         if (ptr == NULL)
2184                 return -ENOMEM;
2185
2186         /* Free the old buf */
2187         if (buf->lb_buf != NULL) {
2188                 memcpy(ptr, buf->lb_buf, buf->lb_len);
2189                 OBD_FREE_LARGE(buf->lb_buf, buf->lb_len);
2190         }
2191
2192         buf->lb_buf = ptr;
2193         buf->lb_len = len;
2194         return 0;
2195 }
2196 EXPORT_SYMBOL(lu_buf_check_and_grow);