fs/afs/vlocation.c

   1 /* vlocation.c: volume location management
   2  *
   3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/fs.h>
  17 #include <linux/pagemap.h>
  18 #include "volume.h"
  19 #include "cell.h"
  20 #include "cmservice.h"
  21 #include "fsclient.h"
  22 #include "vlclient.h"
  23 #include "kafstimod.h"
  24 #include <rxrpc/connection.h>
  25 #include "internal.h"
  26
  27 #define AFS_VLDB_TIMEOUT HZ*1000
  28
  29 static void afs_vlocation_update_timer(struct afs_timer *timer);
  30 static void afs_vlocation_update_attend(struct afs_async_op *op);
  31 static void afs_vlocation_update_discard(struct afs_async_op *op);
  32 static void __afs_put_vlocation(struct afs_vlocation *vlocation);
  33
  34 static void __afs_vlocation_timeout(struct afs_timer *timer)
  35 {
  36         struct afs_vlocation *vlocation =
  37                 list_entry(timer, struct afs_vlocation, timeout);
  38
  39         _debug("VL TIMEOUT [%s{u=%d}]",
  40                vlocation->vldb.name, atomic_read(&vlocation->usage));
  41
  42         afs_vlocation_do_timeout(vlocation);
  43 }
  44
  45 static const struct afs_timer_ops afs_vlocation_timer_ops = {
  46         .timed_out      = __afs_vlocation_timeout,
  47 };
  48
  49 static const struct afs_timer_ops afs_vlocation_update_timer_ops = {
  50         .timed_out      = afs_vlocation_update_timer,
  51 };
  52
  53 static const struct afs_async_op_ops afs_vlocation_update_op_ops = {
  54         .attend         = afs_vlocation_update_attend,
  55         .discard        = afs_vlocation_update_discard,
  56 };
  57
  58 static LIST_HEAD(afs_vlocation_update_pendq);   /* queue of VLs awaiting update */
  59 static struct afs_vlocation *afs_vlocation_update;      /* VL currently being updated */
  60 static DEFINE_SPINLOCK(afs_vlocation_update_lock); /* lock guarding update queue */
  61
  62 #ifdef AFS_CACHING_SUPPORT
  63 static cachefs_match_val_t afs_vlocation_cache_match(void *target,
  64                                                      const void *entry);
  65 static void afs_vlocation_cache_update(void *source, void *entry);
  66
  67 struct cachefs_index_def afs_vlocation_cache_index_def = {
  68         .name           = "vldb",
  69         .data_size      = sizeof(struct afs_cache_vlocation),
  70         .keys[0]        = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 },
  71         .match          = afs_vlocation_cache_match,
  72         .update         = afs_vlocation_cache_update,
  73 };
  74 #endif
  75
  76 /*****************************************************************************/
  77 /*
  78  * iterate through the VL servers in a cell until one of them admits knowing
  79  * about the volume in question
  80  * - caller must have cell->vl_sem write-locked
  81  */
  82 static int afs_vlocation_access_vl_by_name(struct afs_vlocation *vlocation,
  83                                            const char *name,
  84                                            unsigned namesz,
  85                                            struct afs_cache_vlocation *vldb)
  86 {
  87         struct afs_server *server = NULL;
  88         struct afs_cell *cell = vlocation->cell;
  89         int count, ret;
  90
  91         _enter("%s,%*.*s,%u", cell->name, namesz, namesz, name, namesz);
  92
  93         ret = -ENOMEDIUM;
  94         for (count = cell->vl_naddrs; count > 0; count--) {
  95                 _debug("CellServ[%hu]: %08x",
  96                        cell->vl_curr_svix,
  97                        cell->vl_addrs[cell->vl_curr_svix].s_addr);
  98
  99                 /* try and create a server */
 100                 ret = afs_server_lookup(cell,
 101                                         &cell->vl_addrs[cell->vl_curr_svix],
 102                                         &server);
 103                 switch (ret) {
 104                 case 0:
 105                         break;
 106                 case -ENOMEM:
 107                 case -ENONET:
 108                         goto out;
 109                 default:
 110                         goto rotate;
 111                 }
 112
 113                 /* attempt to access the VL server */
 114                 ret = afs_rxvl_get_entry_by_name(server, name, namesz, vldb);
 115                 switch (ret) {
 116                 case 0:
 117                         afs_put_server(server);
 118                         goto out;
 119                 case -ENOMEM:
 120                 case -ENONET:
 121                 case -ENETUNREACH:
 122                 case -EHOSTUNREACH:
 123                 case -ECONNREFUSED:
 124                         down_write(&server->sem);
 125                         if (server->vlserver) {
 126                                 rxrpc_put_connection(server->vlserver);
 127                                 server->vlserver = NULL;
 128                         }
 129                         up_write(&server->sem);
 130                         afs_put_server(server);
 131                         if (ret == -ENOMEM || ret == -ENONET)
 132                                 goto out;
 133                         goto rotate;
 134                 case -ENOMEDIUM:
 135                         afs_put_server(server);
 136                         goto out;
 137                 default:
 138                         afs_put_server(server);
 139                         ret = -ENOMEDIUM;
 140                         goto rotate;
 141                 }
 142
 143                 /* rotate the server records upon lookup failure */
 144         rotate:
 145                 cell->vl_curr_svix++;
 146                 cell->vl_curr_svix %= cell->vl_naddrs;
 147         }
 148
 149  out:
 150         _leave(" = %d", ret);
 151         return ret;
 152
 153 } /* end afs_vlocation_access_vl_by_name() */
 154
 155 /*****************************************************************************/
 156 /*
 157  * iterate through the VL servers in a cell until one of them admits knowing
 158  * about the volume in question
 159  * - caller must have cell->vl_sem write-locked
 160  */
 161 static int afs_vlocation_access_vl_by_id(struct afs_vlocation *vlocation,
 162                                          afs_volid_t volid,
 163                                          afs_voltype_t voltype,
 164                                          struct afs_cache_vlocation *vldb)
 165 {
 166         struct afs_server *server = NULL;
 167         struct afs_cell *cell = vlocation->cell;
 168         int count, ret;
 169
 170         _enter("%s,%x,%d,", cell->name, volid, voltype);
 171
 172         ret = -ENOMEDIUM;
 173         for (count = cell->vl_naddrs; count > 0; count--) {
 174                 _debug("CellServ[%hu]: %08x",
 175                        cell->vl_curr_svix,
 176                        cell->vl_addrs[cell->vl_curr_svix].s_addr);
 177
 178                 /* try and create a server */
 179                 ret = afs_server_lookup(cell,
 180                                         &cell->vl_addrs[cell->vl_curr_svix],
 181                                         &server);
 182                 switch (ret) {
 183                 case 0:
 184                         break;
 185                 case -ENOMEM:
 186                 case -ENONET:
 187                         goto out;
 188                 default:
 189                         goto rotate;
 190                 }
 191
 192                 /* attempt to access the VL server */
 193                 ret = afs_rxvl_get_entry_by_id(server, volid, voltype, vldb);
 194                 switch (ret) {
 195                 case 0:
 196                         afs_put_server(server);
 197                         goto out;
 198                 case -ENOMEM:
 199                 case -ENONET:
 200                 case -ENETUNREACH:
 201                 case -EHOSTUNREACH:
 202                 case -ECONNREFUSED:
 203                         down_write(&server->sem);
 204                         if (server->vlserver) {
 205                                 rxrpc_put_connection(server->vlserver);
 206                                 server->vlserver = NULL;
 207                         }
 208                         up_write(&server->sem);
 209                         afs_put_server(server);
 210                         if (ret == -ENOMEM || ret == -ENONET)
 211                                 goto out;
 212                         goto rotate;
 213                 case -ENOMEDIUM:
 214                         afs_put_server(server);
 215                         goto out;
 216                 default:
 217                         afs_put_server(server);
 218                         ret = -ENOMEDIUM;
 219                         goto rotate;
 220                 }
 221
 222                 /* rotate the server records upon lookup failure */
 223         rotate:
 224                 cell->vl_curr_svix++;
 225                 cell->vl_curr_svix %= cell->vl_naddrs;
 226         }
 227
 228  out:
 229         _leave(" = %d", ret);
 230         return ret;
 231
 232 } /* end afs_vlocation_access_vl_by_id() */
 233
 234 /*****************************************************************************/
 235 /*
 236  * lookup volume location
 237  * - caller must have cell->vol_sem write-locked
 238  * - iterate through the VL servers in a cell until one of them admits knowing
 239  *   about the volume in question
 240  * - lookup in the local cache if not able to find on the VL server
 241  * - insert/update in the local cache if did get a VL response
 242  */
 243 int afs_vlocation_lookup(struct afs_cell *cell,
 244                          const char *name,
 245                          unsigned namesz,
 246                          struct afs_vlocation **_vlocation)
 247 {
 248         struct afs_cache_vlocation vldb;
 249         struct afs_vlocation *vlocation;
 250         afs_voltype_t voltype;
 251         afs_volid_t vid;
 252         int active = 0, ret;
 253
 254         _enter("{%s},%*.*s,%u,", cell->name, namesz, namesz, name, namesz);
 255
 256         if (namesz > sizeof(vlocation->vldb.name)) {
 257                 _leave(" = -ENAMETOOLONG");
 258                 return -ENAMETOOLONG;
 259         }
 260
 261         /* search the cell's active list first */
 262         list_for_each_entry(vlocation, &cell->vl_list, link) {
 263                 if (namesz < sizeof(vlocation->vldb.name) &&
 264                     vlocation->vldb.name[namesz] != '\0')
 265                         continue;
 266
 267                 if (memcmp(vlocation->vldb.name, name, namesz) == 0)
 268                         goto found_in_memory;
 269         }
 270
 271         /* search the cell's graveyard list second */
 272         spin_lock(&cell->vl_gylock);
 273         list_for_each_entry(vlocation, &cell->vl_graveyard, link) {
 274                 if (namesz < sizeof(vlocation->vldb.name) &&
 275                     vlocation->vldb.name[namesz] != '\0')
 276                         continue;
 277
 278                 if (memcmp(vlocation->vldb.name, name, namesz) == 0)
 279                         goto found_in_graveyard;
 280         }
 281         spin_unlock(&cell->vl_gylock);
 282
 283         /* not in the cell's in-memory lists - create a new record */
 284         vlocation = kmalloc(sizeof(struct afs_vlocation), GFP_KERNEL);
 285         if (!vlocation)
 286                 return -ENOMEM;
 287
 288         memset(vlocation, 0, sizeof(struct afs_vlocation));
 289         atomic_set(&vlocation->usage, 1);
 290         INIT_LIST_HEAD(&vlocation->link);
 291         rwlock_init(&vlocation->lock);
 292         memcpy(vlocation->vldb.name, name, namesz);
 293
 294         afs_timer_init(&vlocation->timeout, &afs_vlocation_timer_ops);
 295         afs_timer_init(&vlocation->upd_timer, &afs_vlocation_update_timer_ops);
 296         afs_async_op_init(&vlocation->upd_op, &afs_vlocation_update_op_ops);
 297
 298         afs_get_cell(cell);
 299         vlocation->cell = cell;
 300
 301         list_add_tail(&vlocation->link, &cell->vl_list);
 302
 303 #ifdef AFS_CACHING_SUPPORT
 304         /* we want to store it in the cache, plus it might already be
 305          * encached */
 306         cachefs_acquire_cookie(cell->cache,
 307                                &afs_volume_cache_index_def,
 308                                vlocation,
 309                                &vlocation->cache);
 310
 311         if (vlocation->valid)
 312                 goto found_in_cache;
 313 #endif
 314
 315         /* try to look up an unknown volume in the cell VL databases by name */
 316         ret = afs_vlocation_access_vl_by_name(vlocation, name, namesz, &vldb);
 317         if (ret < 0) {
 318                 printk("kAFS: failed to locate '%*.*s' in cell '%s'\n",
 319                        namesz, namesz, name, cell->name);
 320                 goto error;
 321         }
 322
 323         goto found_on_vlserver;
 324
 325  found_in_graveyard:
 326         /* found in the graveyard - resurrect */
 327         _debug("found in graveyard");
 328         atomic_inc(&vlocation->usage);
 329         list_move_tail(&vlocation->link, &cell->vl_list);
 330         spin_unlock(&cell->vl_gylock);
 331
 332         afs_kafstimod_del_timer(&vlocation->timeout);
 333         goto active;
 334
 335  found_in_memory:
 336         /* found in memory - check to see if it's active */
 337         _debug("found in memory");
 338         atomic_inc(&vlocation->usage);
 339
 340  active:
 341         active = 1;
 342
 343 #ifdef AFS_CACHING_SUPPORT
 344  found_in_cache:
 345 #endif
 346         /* try to look up a cached volume in the cell VL databases by ID */
 347         _debug("found in cache");
 348
 349         _debug("Locally Cached: %s %02x { %08x(%x) %08x(%x) %08x(%x) }",
 350                vlocation->vldb.name,
 351                vlocation->vldb.vidmask,
 352                ntohl(vlocation->vldb.servers[0].s_addr),
 353                vlocation->vldb.srvtmask[0],
 354                ntohl(vlocation->vldb.servers[1].s_addr),
 355                vlocation->vldb.srvtmask[1],
 356                ntohl(vlocation->vldb.servers[2].s_addr),
 357                vlocation->vldb.srvtmask[2]
 358                );
 359
 360         _debug("Vids: %08x %08x %08x",
 361                vlocation->vldb.vid[0],
 362                vlocation->vldb.vid[1],
 363                vlocation->vldb.vid[2]);
 364
 365         if (vlocation->vldb.vidmask & AFS_VOL_VTM_RW) {
 366                 vid = vlocation->vldb.vid[0];
 367                 voltype = AFSVL_RWVOL;
 368         }
 369         else if (vlocation->vldb.vidmask & AFS_VOL_VTM_RO) {
 370                 vid = vlocation->vldb.vid[1];
 371                 voltype = AFSVL_ROVOL;
 372         }
 373         else if (vlocation->vldb.vidmask & AFS_VOL_VTM_BAK) {
 374                 vid = vlocation->vldb.vid[2];
 375                 voltype = AFSVL_BACKVOL;
 376         }
 377         else {
 378                 BUG();
 379                 vid = 0;
 380                 voltype = 0;
 381         }
 382
 383         ret = afs_vlocation_access_vl_by_id(vlocation, vid, voltype, &vldb);
 384         switch (ret) {
 385                 /* net error */
 386         default:
 387                 printk("kAFS: failed to volume '%*.*s' (%x) up in '%s': %d\n",
 388                        namesz, namesz, name, vid, cell->name, ret);
 389                 goto error;
 390
 391                 /* pulled from local cache into memory */
 392         case 0:
 393                 goto found_on_vlserver;
 394
 395                 /* uh oh... looks like the volume got deleted */
 396         case -ENOMEDIUM:
 397                 printk("kAFS: volume '%*.*s' (%x) does not exist '%s'\n",
 398                        namesz, namesz, name, vid, cell->name);
 399
 400                 /* TODO: make existing record unavailable */
 401                 goto error;
 402         }
 403
 404  found_on_vlserver:
 405         _debug("Done VL Lookup: %*.*s %02x { %08x(%x) %08x(%x) %08x(%x) }",
 406                namesz, namesz, name,
 407                vldb.vidmask,
 408                ntohl(vldb.servers[0].s_addr), vldb.srvtmask[0],
 409                ntohl(vldb.servers[1].s_addr), vldb.srvtmask[1],
 410                ntohl(vldb.servers[2].s_addr), vldb.srvtmask[2]
 411                );
 412
 413         _debug("Vids: %08x %08x %08x", vldb.vid[0], vldb.vid[1], vldb.vid[2]);
 414
 415         if ((namesz < sizeof(vlocation->vldb.name) &&
 416              vlocation->vldb.name[namesz] != '\0') ||
 417             memcmp(vldb.name, name, namesz) != 0)
 418                 printk("kAFS: name of volume '%*.*s' changed to '%s' on server\n",
 419                        namesz, namesz, name, vldb.name);
 420
 421         memcpy(&vlocation->vldb, &vldb, sizeof(vlocation->vldb));
 422
 423         afs_kafstimod_add_timer(&vlocation->upd_timer, 10 * HZ);
 424
 425 #ifdef AFS_CACHING_SUPPORT
 426         /* update volume entry in local cache */
 427         cachefs_update_cookie(vlocation->cache);
 428 #endif
 429
 430         *_vlocation = vlocation;
 431         _leave(" = 0 (%p)",vlocation);
 432         return 0;
 433
 434  error:
 435         if (vlocation) {
 436                 if (active) {
 437                         __afs_put_vlocation(vlocation);
 438                 }
 439                 else {
 440                         list_del(&vlocation->link);
 441 #ifdef AFS_CACHING_SUPPORT
 442                         cachefs_relinquish_cookie(vlocation->cache, 0);
 443 #endif
 444                         afs_put_cell(vlocation->cell);
 445                         kfree(vlocation);
 446                 }
 447         }
 448
 449         _leave(" = %d", ret);
 450         return ret;
 451 } /* end afs_vlocation_lookup() */
 452
 453 /*****************************************************************************/
 454 /*
 455  * finish using a volume location record
 456  * - caller must have cell->vol_sem write-locked
 457  */
 458 static void __afs_put_vlocation(struct afs_vlocation *vlocation)
 459 {
 460         struct afs_cell *cell;
 461
 462         if (!vlocation)
 463                 return;
 464
 465         _enter("%s", vlocation->vldb.name);
 466
 467         cell = vlocation->cell;
 468
 469         /* sanity check */
 470         BUG_ON(atomic_read(&vlocation->usage) <= 0);
 471
 472         spin_lock(&cell->vl_gylock);
 473         if (likely(!atomic_dec_and_test(&vlocation->usage))) {
 474                 spin_unlock(&cell->vl_gylock);
 475                 _leave("");
 476                 return;
 477         }
 478
 479         /* move to graveyard queue */
 480         list_move_tail(&vlocation->link,&cell->vl_graveyard);
 481
 482         /* remove from pending timeout queue (refcounted if actually being
 483          * updated) */
 484         list_del_init(&vlocation->upd_op.link);
 485
 486         /* time out in 10 secs */
 487         afs_kafstimod_del_timer(&vlocation->upd_timer);
 488         afs_kafstimod_add_timer(&vlocation->timeout, 10 * HZ);
 489
 490         spin_unlock(&cell->vl_gylock);
 491
 492         _leave(" [killed]");
 493 } /* end __afs_put_vlocation() */
 494
 495 /*****************************************************************************/
 496 /*
 497  * finish using a volume location record
 498  */
 499 void afs_put_vlocation(struct afs_vlocation *vlocation)
 500 {
 501         if (vlocation) {
 502                 struct afs_cell *cell = vlocation->cell;
 503
 504                 down_write(&cell->vl_sem);
 505                 __afs_put_vlocation(vlocation);
 506                 up_write(&cell->vl_sem);
 507         }
 508 } /* end afs_put_vlocation() */
 509
 510 /*****************************************************************************/
 511 /*
 512  * timeout vlocation record
 513  * - removes from the cell's graveyard if the usage count is zero
 514  */
 515 void afs_vlocation_do_timeout(struct afs_vlocation *vlocation)
 516 {
 517         struct afs_cell *cell;
 518
 519         _enter("%s", vlocation->vldb.name);
 520
 521         cell = vlocation->cell;
 522
 523         BUG_ON(atomic_read(&vlocation->usage) < 0);
 524
 525         /* remove from graveyard if still dead */
 526         spin_lock(&cell->vl_gylock);
 527         if (atomic_read(&vlocation->usage) == 0)
 528                 list_del_init(&vlocation->link);
 529         else
 530                 vlocation = NULL;
 531         spin_unlock(&cell->vl_gylock);
 532
 533         if (!vlocation) {
 534                 _leave("");
 535                 return; /* resurrected */
 536         }
 537
 538         /* we can now destroy it properly */
 539 #ifdef AFS_CACHING_SUPPORT
 540         cachefs_relinquish_cookie(vlocation->cache, 0);
 541 #endif
 542         afs_put_cell(cell);
 543
 544         kfree(vlocation);
 545
 546         _leave(" [destroyed]");
 547 } /* end afs_vlocation_do_timeout() */
 548
 549 /*****************************************************************************/
 550 /*
 551  * send an update operation to the currently selected server
 552  */
 553 static int afs_vlocation_update_begin(struct afs_vlocation *vlocation)
 554 {
 555         afs_voltype_t voltype;
 556         afs_volid_t vid;
 557         int ret;
 558
 559         _enter("%s{ufs=%u ucs=%u}",
 560                vlocation->vldb.name,
 561                vlocation->upd_first_svix,
 562                vlocation->upd_curr_svix);
 563
 564         /* try to look up a cached volume in the cell VL databases by ID */
 565         if (vlocation->vldb.vidmask & AFS_VOL_VTM_RW) {
 566                 vid = vlocation->vldb.vid[0];
 567                 voltype = AFSVL_RWVOL;
 568         }
 569         else if (vlocation->vldb.vidmask & AFS_VOL_VTM_RO) {
 570                 vid = vlocation->vldb.vid[1];
 571                 voltype = AFSVL_ROVOL;
 572         }
 573         else if (vlocation->vldb.vidmask & AFS_VOL_VTM_BAK) {
 574                 vid = vlocation->vldb.vid[2];
 575                 voltype = AFSVL_BACKVOL;
 576         }
 577         else {
 578                 BUG();
 579                 vid = 0;
 580                 voltype = 0;
 581         }
 582
 583         /* contact the chosen server */
 584         ret = afs_server_lookup(
 585                 vlocation->cell,
 586                 &vlocation->cell->vl_addrs[vlocation->upd_curr_svix],
 587                 &vlocation->upd_op.server);
 588
 589         switch (ret) {
 590         case 0:
 591                 break;
 592         case -ENOMEM:
 593         case -ENONET:
 594         default:
 595                 _leave(" = %d", ret);
 596                 return ret;
 597         }
 598
 599         /* initiate the update operation */
 600         ret = afs_rxvl_get_entry_by_id_async(&vlocation->upd_op, vid, voltype);
 601         if (ret < 0) {
 602                 _leave(" = %d", ret);
 603                 return ret;
 604         }
 605
 606         _leave(" = %d", ret);
 607         return ret;
 608 } /* end afs_vlocation_update_begin() */
 609
 610 /*****************************************************************************/
 611 /*
 612  * abandon updating a VL record
 613  * - does not restart the update timer
 614  */
 615 static void afs_vlocation_update_abandon(struct afs_vlocation *vlocation,
 616                                          afs_vlocation_upd_t state,
 617                                          int ret)
 618 {
 619         _enter("%s,%u", vlocation->vldb.name, state);
 620
 621         if (ret < 0)
 622                 printk("kAFS: Abandoning VL update '%s': %d\n",
 623                        vlocation->vldb.name, ret);
 624
 625         /* discard the server record */
 626         afs_put_server(vlocation->upd_op.server);
 627         vlocation->upd_op.server = NULL;
 628
 629         spin_lock(&afs_vlocation_update_lock);
 630         afs_vlocation_update = NULL;
 631         vlocation->upd_state = state;
 632
 633         /* TODO: start updating next VL record on pending list */
 634
 635         spin_unlock(&afs_vlocation_update_lock);
 636
 637         _leave("");
 638 } /* end afs_vlocation_update_abandon() */
 639
 640 /*****************************************************************************/
 641 /*
 642  * handle periodic update timeouts and busy retry timeouts
 643  * - called from kafstimod
 644  */
 645 static void afs_vlocation_update_timer(struct afs_timer *timer)
 646 {
 647         struct afs_vlocation *vlocation =
 648                 list_entry(timer, struct afs_vlocation, upd_timer);
 649         int ret;
 650
 651         _enter("%s", vlocation->vldb.name);
 652
 653         /* only update if not in the graveyard (defend against putting too) */
 654         spin_lock(&vlocation->cell->vl_gylock);
 655
 656         if (!atomic_read(&vlocation->usage))
 657                 goto out_unlock1;
 658
 659         spin_lock(&afs_vlocation_update_lock);
 660
 661         /* if we were woken up due to EBUSY sleep then restart immediately if
 662          * possible or else jump to front of pending queue */
 663         if (vlocation->upd_state == AFS_VLUPD_BUSYSLEEP) {
 664                 if (afs_vlocation_update) {
 665                         list_add(&vlocation->upd_op.link,
 666                                  &afs_vlocation_update_pendq);
 667                 }
 668                 else {
 669                         afs_get_vlocation(vlocation);
 670                         afs_vlocation_update = vlocation;
 671                         vlocation->upd_state = AFS_VLUPD_INPROGRESS;
 672                 }
 673                 goto out_unlock2;
 674         }
 675
 676         /* put on pending queue if there's already another update in progress */
 677         if (afs_vlocation_update) {
 678                 vlocation->upd_state = AFS_VLUPD_PENDING;
 679                 list_add_tail(&vlocation->upd_op.link,
 680                               &afs_vlocation_update_pendq);
 681                 goto out_unlock2;
 682         }
 683
 684         /* hold a ref on it while actually updating */
 685         afs_get_vlocation(vlocation);
 686         afs_vlocation_update = vlocation;
 687         vlocation->upd_state = AFS_VLUPD_INPROGRESS;
 688
 689         spin_unlock(&afs_vlocation_update_lock);
 690         spin_unlock(&vlocation->cell->vl_gylock);
 691
 692         /* okay... we can start the update */
 693         _debug("BEGIN VL UPDATE [%s]", vlocation->vldb.name);
 694         vlocation->upd_first_svix = vlocation->cell->vl_curr_svix;
 695         vlocation->upd_curr_svix = vlocation->upd_first_svix;
 696         vlocation->upd_rej_cnt = 0;
 697         vlocation->upd_busy_cnt = 0;
 698
 699         ret = afs_vlocation_update_begin(vlocation);
 700         if (ret < 0) {
 701                 afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, ret);
 702                 afs_kafstimod_add_timer(&vlocation->upd_timer,
 703                                         AFS_VLDB_TIMEOUT);
 704                 afs_put_vlocation(vlocation);
 705         }
 706
 707         _leave("");
 708         return;
 709
 710  out_unlock2:
 711         spin_unlock(&afs_vlocation_update_lock);
 712  out_unlock1:
 713         spin_unlock(&vlocation->cell->vl_gylock);
 714         _leave("");
 715         return;
 716
 717 } /* end afs_vlocation_update_timer() */
 718
 719 /*****************************************************************************/
 720 /*
 721  * attend to an update operation upon which an event happened
 722  * - called in kafsasyncd context
 723  */
 724 static void afs_vlocation_update_attend(struct afs_async_op *op)
 725 {
 726         struct afs_cache_vlocation vldb;
 727         struct afs_vlocation *vlocation =
 728                 list_entry(op, struct afs_vlocation, upd_op);
 729         unsigned tmp;
 730         int ret;
 731
 732         _enter("%s", vlocation->vldb.name);
 733
 734         ret = afs_rxvl_get_entry_by_id_async2(op, &vldb);
 735         switch (ret) {
 736         case -EAGAIN:
 737                 _leave(" [unfinished]");
 738                 return;
 739
 740         case 0:
 741                 _debug("END VL UPDATE: %d\n", ret);
 742                 vlocation->valid = 1;
 743
 744                 _debug("Done VL Lookup: %02x { %08x(%x) %08x(%x) %08x(%x) }",
 745                        vldb.vidmask,
 746                        ntohl(vldb.servers[0].s_addr), vldb.srvtmask[0],
 747                        ntohl(vldb.servers[1].s_addr), vldb.srvtmask[1],
 748                        ntohl(vldb.servers[2].s_addr), vldb.srvtmask[2]
 749                        );
 750
 751                 _debug("Vids: %08x %08x %08x",
 752                        vldb.vid[0], vldb.vid[1], vldb.vid[2]);
 753
 754                 afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, 0);
 755
 756                 down_write(&vlocation->cell->vl_sem);
 757
 758                 /* actually update the cache */
 759                 if (strncmp(vldb.name, vlocation->vldb.name,
 760                             sizeof(vlocation->vldb.name)) != 0)
 761                         printk("kAFS: name of volume '%s'"
 762                                " changed to '%s' on server\n",
 763                                vlocation->vldb.name, vldb.name);
 764
 765                 memcpy(&vlocation->vldb, &vldb, sizeof(vlocation->vldb));
 766
 767 #if 0
 768                 /* TODO update volume entry in local cache */
 769 #endif
 770
 771                 up_write(&vlocation->cell->vl_sem);
 772
 773                 if (ret < 0)
 774                         printk("kAFS: failed to update local cache: %d\n", ret);
 775
 776                 afs_kafstimod_add_timer(&vlocation->upd_timer,
 777                                         AFS_VLDB_TIMEOUT);
 778                 afs_put_vlocation(vlocation);
 779                 _leave(" [found]");
 780                 return;
 781
 782         case -ENOMEDIUM:
 783                 vlocation->upd_rej_cnt++;
 784                 goto try_next;
 785
 786                 /* the server is locked - retry in a very short while */
 787         case -EBUSY:
 788                 vlocation->upd_busy_cnt++;
 789                 if (vlocation->upd_busy_cnt > 3)
 790                         goto try_next; /* too many retries */
 791
 792                 afs_vlocation_update_abandon(vlocation,
 793                                              AFS_VLUPD_BUSYSLEEP, 0);
 794                 afs_kafstimod_add_timer(&vlocation->upd_timer, HZ / 2);
 795                 afs_put_vlocation(vlocation);
 796                 _leave(" [busy]");
 797                 return;
 798
 799         case -ENETUNREACH:
 800         case -EHOSTUNREACH:
 801         case -ECONNREFUSED:
 802         case -EREMOTEIO:
 803                 /* record bad vlserver info in the cell too
 804                  * - TODO: use down_write_trylock() if available
 805                  */
 806                 if (vlocation->upd_curr_svix == vlocation->cell->vl_curr_svix)
 807                         vlocation->cell->vl_curr_svix =
 808                                 vlocation->cell->vl_curr_svix %
 809                                 vlocation->cell->vl_naddrs;
 810
 811         case -EBADRQC:
 812         case -EINVAL:
 813         case -EACCES:
 814         case -EBADMSG:
 815                 goto try_next;
 816
 817         default:
 818                 goto abandon;
 819         }
 820
 821         /* try contacting the next server */
 822  try_next:
 823         vlocation->upd_busy_cnt = 0;
 824
 825         /* discard the server record */
 826         afs_put_server(vlocation->upd_op.server);
 827         vlocation->upd_op.server = NULL;
 828
 829         tmp = vlocation->cell->vl_naddrs;
 830         if (tmp == 0)
 831                 goto abandon;
 832
 833         vlocation->upd_curr_svix++;
 834         if (vlocation->upd_curr_svix >= tmp)
 835                 vlocation->upd_curr_svix = 0;
 836         if (vlocation->upd_first_svix >= tmp)
 837                 vlocation->upd_first_svix = tmp - 1;
 838
 839         /* move to the next server */
 840         if (vlocation->upd_curr_svix != vlocation->upd_first_svix) {
 841                 afs_vlocation_update_begin(vlocation);
 842                 _leave(" [next]");
 843                 return;
 844         }
 845
 846         /* run out of servers to try - was the volume rejected? */
 847         if (vlocation->upd_rej_cnt > 0) {
 848                 printk("kAFS: Active volume no longer valid '%s'\n",
 849                        vlocation->vldb.name);
 850                 vlocation->valid = 0;
 851                 afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, 0);
 852                 afs_kafstimod_add_timer(&vlocation->upd_timer,
 853                                         AFS_VLDB_TIMEOUT);
 854                 afs_put_vlocation(vlocation);
 855                 _leave(" [invalidated]");
 856                 return;
 857         }
 858
 859         /* abandon the update */
 860  abandon:
 861         afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, ret);
 862         afs_kafstimod_add_timer(&vlocation->upd_timer, HZ * 10);
 863         afs_put_vlocation(vlocation);
 864         _leave(" [abandoned]");
 865
 866 } /* end afs_vlocation_update_attend() */
 867
 868 /*****************************************************************************/
 869 /*
 870  * deal with an update operation being discarded
 871  * - called in kafsasyncd context when it's dying due to rmmod
 872  * - the call has already been aborted and put()'d
 873  */
 874 static void afs_vlocation_update_discard(struct afs_async_op *op)
 875 {
 876         struct afs_vlocation *vlocation =
 877                 list_entry(op, struct afs_vlocation, upd_op);
 878
 879         _enter("%s", vlocation->vldb.name);
 880
 881         afs_put_server(op->server);
 882         op->server = NULL;
 883
 884         afs_put_vlocation(vlocation);
 885
 886         _leave("");
 887 } /* end afs_vlocation_update_discard() */
 888
 889 /*****************************************************************************/
 890 /*
 891  * match a VLDB record stored in the cache
 892  * - may also load target from entry
 893  */
 894 #ifdef AFS_CACHING_SUPPORT
 895 static cachefs_match_val_t afs_vlocation_cache_match(void *target,
 896                                                      const void *entry)
 897 {
 898         const struct afs_cache_vlocation *vldb = entry;
 899         struct afs_vlocation *vlocation = target;
 900
 901         _enter("{%s},{%s}", vlocation->vldb.name, vldb->name);
 902
 903         if (strncmp(vlocation->vldb.name, vldb->name, sizeof(vldb->name)) == 0
 904             ) {
 905                 if (!vlocation->valid ||
 906                     vlocation->vldb.rtime == vldb->rtime
 907                     ) {
 908                         vlocation->vldb = *vldb;
 909                         vlocation->valid = 1;
 910                         _leave(" = SUCCESS [c->m]");
 911                         return CACHEFS_MATCH_SUCCESS;
 912                 }
 913                 /* need to update cache if cached info differs */
 914                 else if (memcmp(&vlocation->vldb, vldb, sizeof(*vldb)) != 0) {
 915                         /* delete if VIDs for this name differ */
 916                         if (memcmp(&vlocation->vldb.vid,
 917                                    &vldb->vid,
 918                                    sizeof(vldb->vid)) != 0) {
 919                                 _leave(" = DELETE");
 920                                 return CACHEFS_MATCH_SUCCESS_DELETE;
 921                         }
 922
 923                         _leave(" = UPDATE");
 924                         return CACHEFS_MATCH_SUCCESS_UPDATE;
 925                 }
 926                 else {
 927                         _leave(" = SUCCESS");
 928                         return CACHEFS_MATCH_SUCCESS;
 929                 }
 930         }
 931
 932         _leave(" = FAILED");
 933         return CACHEFS_MATCH_FAILED;
 934 } /* end afs_vlocation_cache_match() */
 935 #endif
 936
 937 /*****************************************************************************/
 938 /*
 939  * update a VLDB record stored in the cache
 940  */
 941 #ifdef AFS_CACHING_SUPPORT
 942 static void afs_vlocation_cache_update(void *source, void *entry)
 943 {
 944         struct afs_cache_vlocation *vldb = entry;
 945         struct afs_vlocation *vlocation = source;
 946
 947         _enter("");
 948
 949         *vldb = vlocation->vldb;
 950
 951 } /* end afs_vlocation_cache_update() */
 952 #endif