git.oblomov.eu Git - linux-2.6/blob - fs/afs/vlocation.c

   1 /* AFS volume location management
   2  *
   3  * Copyright (C) 2002, 2007 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/sched.h>
  16 #include "internal.h"
  17
  18 static unsigned afs_vlocation_timeout = 10;     /* volume location timeout in seconds */
  19 static unsigned afs_vlocation_update_timeout = 10 * 60;
  20
  21 static void afs_vlocation_reaper(struct work_struct *);
  22 static void afs_vlocation_updater(struct work_struct *);
  23
  24 static LIST_HEAD(afs_vlocation_updates);
  25 static LIST_HEAD(afs_vlocation_graveyard);
  26 static DEFINE_SPINLOCK(afs_vlocation_updates_lock);
  27 static DEFINE_SPINLOCK(afs_vlocation_graveyard_lock);
  28 static DECLARE_DELAYED_WORK(afs_vlocation_reap, afs_vlocation_reaper);
  29 static DECLARE_DELAYED_WORK(afs_vlocation_update, afs_vlocation_updater);
  30 static struct workqueue_struct *afs_vlocation_update_worker;
  31
  32 /*
  33  * iterate through the VL servers in a cell until one of them admits knowing
  34  * about the volume in question
  35  */
  36 static int afs_vlocation_access_vl_by_name(struct afs_vlocation *vl,
  37                                            struct key *key,
  38                                            struct afs_cache_vlocation *vldb)
  39 {
  40         struct afs_cell *cell = vl->cell;
  41         struct in_addr addr;
  42         int count, ret;
  43
  44         _enter("%s,%s", cell->name, vl->vldb.name);
  45
  46         down_write(&vl->cell->vl_sem);
  47         ret = -ENOMEDIUM;
  48         for (count = cell->vl_naddrs; count > 0; count--) {
  49                 addr = cell->vl_addrs[cell->vl_curr_svix];
  50
  51                 _debug("CellServ[%hu]: %08x", cell->vl_curr_svix, addr.s_addr);
  52
  53                 /* attempt to access the VL server */
  54                 ret = afs_vl_get_entry_by_name(&addr, key, vl->vldb.name, vldb,
  55                                                &afs_sync_call);
  56                 switch (ret) {
  57                 case 0:
  58                         goto out;
  59                 case -ENOMEM:
  60                 case -ENONET:
  61                 case -ENETUNREACH:
  62                 case -EHOSTUNREACH:
  63                 case -ECONNREFUSED:
  64                         if (ret == -ENOMEM || ret == -ENONET)
  65                                 goto out;
  66                         goto rotate;
  67                 case -ENOMEDIUM:
  68                 case -EKEYREJECTED:
  69                 case -EKEYEXPIRED:
  70                         goto out;
  71                 default:
  72                         ret = -EIO;
  73                         goto rotate;
  74                 }
  75
  76                 /* rotate the server records upon lookup failure */
  77         rotate:
  78                 cell->vl_curr_svix++;
  79                 cell->vl_curr_svix %= cell->vl_naddrs;
  80         }
  81
  82 out:
  83         up_write(&vl->cell->vl_sem);
  84         _leave(" = %d", ret);
  85         return ret;
  86 }
  87
  88 /*
  89  * iterate through the VL servers in a cell until one of them admits knowing
  90  * about the volume in question
  91  */
  92 static int afs_vlocation_access_vl_by_id(struct afs_vlocation *vl,
  93                                          struct key *key,
  94                                          afs_volid_t volid,
  95                                          afs_voltype_t voltype,
  96                                          struct afs_cache_vlocation *vldb)
  97 {
  98         struct afs_cell *cell = vl->cell;
  99         struct in_addr addr;
 100         int count, ret;
 101
 102         _enter("%s,%x,%d,", cell->name, volid, voltype);
 103
 104         down_write(&vl->cell->vl_sem);
 105         ret = -ENOMEDIUM;
 106         for (count = cell->vl_naddrs; count > 0; count--) {
 107                 addr = cell->vl_addrs[cell->vl_curr_svix];
 108
 109                 _debug("CellServ[%hu]: %08x", cell->vl_curr_svix, addr.s_addr);
 110
 111                 /* attempt to access the VL server */
 112                 ret = afs_vl_get_entry_by_id(&addr, key, volid, voltype, vldb,
 113                                              &afs_sync_call);
 114                 switch (ret) {
 115                 case 0:
 116                         goto out;
 117                 case -ENOMEM:
 118                 case -ENONET:
 119                 case -ENETUNREACH:
 120                 case -EHOSTUNREACH:
 121                 case -ECONNREFUSED:
 122                         if (ret == -ENOMEM || ret == -ENONET)
 123                                 goto out;
 124                         goto rotate;
 125                 case -EBUSY:
 126                         vl->upd_busy_cnt++;
 127                         if (vl->upd_busy_cnt <= 3) {
 128                                 if (vl->upd_busy_cnt > 1) {
 129                                         /* second+ BUSY - sleep a little bit */
 130                                         set_current_state(TASK_UNINTERRUPTIBLE);
 131                                         schedule_timeout(1);
 132                                         __set_current_state(TASK_RUNNING);
 133                                 }
 134                                 continue;
 135                         }
 136                         break;
 137                 case -ENOMEDIUM:
 138                         vl->upd_rej_cnt++;
 139                         goto rotate;
 140                 default:
 141                         ret = -EIO;
 142                         goto rotate;
 143                 }
 144
 145                 /* rotate the server records upon lookup failure */
 146         rotate:
 147                 cell->vl_curr_svix++;
 148                 cell->vl_curr_svix %= cell->vl_naddrs;
 149                 vl->upd_busy_cnt = 0;
 150         }
 151
 152 out:
 153         if (ret < 0 && vl->upd_rej_cnt > 0) {
 154                 printk(KERN_NOTICE "kAFS:"
 155                        " Active volume no longer valid '%s'\n",
 156                        vl->vldb.name);
 157                 vl->valid = 0;
 158                 ret = -ENOMEDIUM;
 159         }
 160
 161         up_write(&vl->cell->vl_sem);
 162         _leave(" = %d", ret);
 163         return ret;
 164 }
 165
 166 /*
 167  * allocate a volume location record
 168  */
 169 static struct afs_vlocation *afs_vlocation_alloc(struct afs_cell *cell,
 170                                                  const char *name,
 171                                                  size_t namesz)
 172 {
 173         struct afs_vlocation *vl;
 174
 175         vl = kzalloc(sizeof(struct afs_vlocation), GFP_KERNEL);
 176         if (vl) {
 177                 vl->cell = cell;
 178                 vl->state = AFS_VL_NEW;
 179                 atomic_set(&vl->usage, 1);
 180                 INIT_LIST_HEAD(&vl->link);
 181                 INIT_LIST_HEAD(&vl->grave);
 182                 INIT_LIST_HEAD(&vl->update);
 183                 init_waitqueue_head(&vl->waitq);
 184                 spin_lock_init(&vl->lock);
 185                 memcpy(vl->vldb.name, name, namesz);
 186         }
 187
 188         _leave(" = %p", vl);
 189         return vl;
 190 }
 191
 192 /*
 193  * update record if we found it in the cache
 194  */
 195 static int afs_vlocation_update_record(struct afs_vlocation *vl,
 196                                        struct key *key,
 197                                        struct afs_cache_vlocation *vldb)
 198 {
 199         afs_voltype_t voltype;
 200         afs_volid_t vid;
 201         int ret;
 202
 203         /* try to look up a cached volume in the cell VL databases by ID */
 204         _debug("Locally Cached: %s %02x { %08x(%x) %08x(%x) %08x(%x) }",
 205                vl->vldb.name,
 206                vl->vldb.vidmask,
 207                ntohl(vl->vldb.servers[0].s_addr),
 208                vl->vldb.srvtmask[0],
 209                ntohl(vl->vldb.servers[1].s_addr),
 210                vl->vldb.srvtmask[1],
 211                ntohl(vl->vldb.servers[2].s_addr),
 212                vl->vldb.srvtmask[2]);
 213
 214         _debug("Vids: %08x %08x %08x",
 215                vl->vldb.vid[0],
 216                vl->vldb.vid[1],
 217                vl->vldb.vid[2]);
 218
 219         if (vl->vldb.vidmask & AFS_VOL_VTM_RW) {
 220                 vid = vl->vldb.vid[0];
 221                 voltype = AFSVL_RWVOL;
 222         } else if (vl->vldb.vidmask & AFS_VOL_VTM_RO) {
 223                 vid = vl->vldb.vid[1];
 224                 voltype = AFSVL_ROVOL;
 225         } else if (vl->vldb.vidmask & AFS_VOL_VTM_BAK) {
 226                 vid = vl->vldb.vid[2];
 227                 voltype = AFSVL_BACKVOL;
 228         } else {
 229                 BUG();
 230                 vid = 0;
 231                 voltype = 0;
 232         }
 233
 234         /* contact the server to make sure the volume is still available
 235          * - TODO: need to handle disconnected operation here
 236          */
 237         ret = afs_vlocation_access_vl_by_id(vl, key, vid, voltype, vldb);
 238         switch (ret) {
 239                 /* net error */
 240         default:
 241                 printk(KERN_WARNING "kAFS:"
 242                        " failed to update volume '%s' (%x) up in '%s': %d\n",
 243                        vl->vldb.name, vid, vl->cell->name, ret);
 244                 _leave(" = %d", ret);
 245                 return ret;
 246
 247                 /* pulled from local cache into memory */
 248         case 0:
 249                 _leave(" = 0");
 250                 return 0;
 251
 252                 /* uh oh... looks like the volume got deleted */
 253         case -ENOMEDIUM:
 254                 printk(KERN_ERR "kAFS:"
 255                        " volume '%s' (%x) does not exist '%s'\n",
 256                        vl->vldb.name, vid, vl->cell->name);
 257
 258                 /* TODO: make existing record unavailable */
 259                 _leave(" = %d", ret);
 260                 return ret;
 261         }
 262 }
 263
 264 /*
 265  * apply the update to a VL record
 266  */
 267 static void afs_vlocation_apply_update(struct afs_vlocation *vl,
 268                                        struct afs_cache_vlocation *vldb)
 269 {
 270         _debug("Done VL Lookup: %s %02x { %08x(%x) %08x(%x) %08x(%x) }",
 271                vldb->name, vldb->vidmask,
 272                ntohl(vldb->servers[0].s_addr), vldb->srvtmask[0],
 273                ntohl(vldb->servers[1].s_addr), vldb->srvtmask[1],
 274                ntohl(vldb->servers[2].s_addr), vldb->srvtmask[2]);
 275
 276         _debug("Vids: %08x %08x %08x",
 277                vldb->vid[0], vldb->vid[1], vldb->vid[2]);
 278
 279         if (strcmp(vldb->name, vl->vldb.name) != 0)
 280                 printk(KERN_NOTICE "kAFS:"
 281                        " name of volume '%s' changed to '%s' on server\n",
 282                        vl->vldb.name, vldb->name);
 283
 284         vl->vldb = *vldb;
 285
 286 #ifdef CONFIG_AFS_FSCACHE
 287         fscache_update_cookie(vl->cache);
 288 #endif
 289 }
 290
 291 /*
 292  * fill in a volume location record, consulting the cache and the VL server
 293  * both
 294  */
 295 static int afs_vlocation_fill_in_record(struct afs_vlocation *vl,
 296                                         struct key *key)
 297 {
 298         struct afs_cache_vlocation vldb;
 299         int ret;
 300
 301         _enter("");
 302
 303         ASSERTCMP(vl->valid, ==, 0);
 304
 305         memset(&vldb, 0, sizeof(vldb));
 306
 307         /* see if we have an in-cache copy (will set vl->valid if there is) */
 308 #ifdef CONFIG_AFS_FSCACHE
 309         vl->cache = fscache_acquire_cookie(vl->cell->cache,
 310                                            &afs_vlocation_cache_index_def, vl);
 311 #endif
 312
 313         if (vl->valid) {
 314                 /* try to update a known volume in the cell VL databases by
 315                  * ID as the name may have changed */
 316                 _debug("found in cache");
 317                 ret = afs_vlocation_update_record(vl, key, &vldb);
 318         } else {
 319                 /* try to look up an unknown volume in the cell VL databases by
 320                  * name */
 321                 ret = afs_vlocation_access_vl_by_name(vl, key, &vldb);
 322                 if (ret < 0) {
 323                         printk("kAFS: failed to locate '%s' in cell '%s'\n",
 324                                vl->vldb.name, vl->cell->name);
 325                         return ret;
 326                 }
 327         }
 328
 329         afs_vlocation_apply_update(vl, &vldb);
 330         _leave(" = 0");
 331         return 0;
 332 }
 333
 334 /*
 335  * queue a vlocation record for updates
 336  */
 337 static void afs_vlocation_queue_for_updates(struct afs_vlocation *vl)
 338 {
 339         struct afs_vlocation *xvl;
 340
 341         /* wait at least 10 minutes before updating... */
 342         vl->update_at = get_seconds() + afs_vlocation_update_timeout;
 343
 344         spin_lock(&afs_vlocation_updates_lock);
 345
 346         if (!list_empty(&afs_vlocation_updates)) {
 347                 /* ... but wait at least 1 second more than the newest record
 348                  * already queued so that we don't spam the VL server suddenly
 349                  * with lots of requests
 350                  */
 351                 xvl = list_entry(afs_vlocation_updates.prev,
 352                                  struct afs_vlocation, update);
 353                 if (vl->update_at <= xvl->update_at)
 354                         vl->update_at = xvl->update_at + 1;
 355         } else {
 356                 queue_delayed_work(afs_vlocation_update_worker,
 357                                    &afs_vlocation_update,
 358                                    afs_vlocation_update_timeout * HZ);
 359         }
 360
 361         list_add_tail(&vl->update, &afs_vlocation_updates);
 362         spin_unlock(&afs_vlocation_updates_lock);
 363 }
 364
 365 /*
 366  * lookup volume location
 367  * - iterate through the VL servers in a cell until one of them admits knowing
 368  *   about the volume in question
 369  * - lookup in the local cache if not able to find on the VL server
 370  * - insert/update in the local cache if did get a VL response
 371  */
 372 struct afs_vlocation *afs_vlocation_lookup(struct afs_cell *cell,
 373                                            struct key *key,
 374                                            const char *name,
 375                                            size_t namesz)
 376 {
 377         struct afs_vlocation *vl;
 378         int ret;
 379
 380         _enter("{%s},{%x},%*.*s,%zu",
 381                cell->name, key_serial(key),
 382                (int) namesz, (int) namesz, name, namesz);
 383
 384         if (namesz >= sizeof(vl->vldb.name)) {
 385                 _leave(" = -ENAMETOOLONG");
 386                 return ERR_PTR(-ENAMETOOLONG);
 387         }
 388
 389         /* see if we have an in-memory copy first */
 390         down_write(&cell->vl_sem);
 391         spin_lock(&cell->vl_lock);
 392         list_for_each_entry(vl, &cell->vl_list, link) {
 393                 if (vl->vldb.name[namesz] != '\0')
 394                         continue;
 395                 if (memcmp(vl->vldb.name, name, namesz) == 0)
 396                         goto found_in_memory;
 397         }
 398         spin_unlock(&cell->vl_lock);
 399
 400         /* not in the cell's in-memory lists - create a new record */
 401         vl = afs_vlocation_alloc(cell, name, namesz);
 402         if (!vl) {
 403                 up_write(&cell->vl_sem);
 404                 return ERR_PTR(-ENOMEM);
 405         }
 406
 407         afs_get_cell(cell);
 408
 409         list_add_tail(&vl->link, &cell->vl_list);
 410         vl->state = AFS_VL_CREATING;
 411         up_write(&cell->vl_sem);
 412
 413 fill_in_record:
 414         ret = afs_vlocation_fill_in_record(vl, key);
 415         if (ret < 0)
 416                 goto error_abandon;
 417         spin_lock(&vl->lock);
 418         vl->state = AFS_VL_VALID;
 419         spin_unlock(&vl->lock);
 420         wake_up(&vl->waitq);
 421
 422         /* update volume entry in local cache */
 423 #ifdef CONFIG_AFS_FSCACHE
 424         fscache_update_cookie(vl->cache);
 425 #endif
 426
 427         /* schedule for regular updates */
 428         afs_vlocation_queue_for_updates(vl);
 429         goto success;
 430
 431 found_in_memory:
 432         /* found in memory */
 433         _debug("found in memory");
 434         atomic_inc(&vl->usage);
 435         spin_unlock(&cell->vl_lock);
 436         if (!list_empty(&vl->grave)) {
 437                 spin_lock(&afs_vlocation_graveyard_lock);
 438                 list_del_init(&vl->grave);
 439                 spin_unlock(&afs_vlocation_graveyard_lock);
 440         }
 441         up_write(&cell->vl_sem);
 442
 443         /* see if it was an abandoned record that we might try filling in */
 444         spin_lock(&vl->lock);
 445         while (vl->state != AFS_VL_VALID) {
 446                 afs_vlocation_state_t state = vl->state;
 447
 448                 _debug("invalid [state %d]", state);
 449
 450                 if (state == AFS_VL_NEW || state == AFS_VL_NO_VOLUME) {
 451                         vl->state = AFS_VL_CREATING;
 452                         spin_unlock(&vl->lock);
 453                         goto fill_in_record;
 454                 }
 455
 456                 /* must now wait for creation or update by someone else to
 457                  * complete */
 458                 _debug("wait");
 459
 460                 spin_unlock(&vl->lock);
 461                 ret = wait_event_interruptible(vl->waitq,
 462                                                vl->state == AFS_VL_NEW ||
 463                                                vl->state == AFS_VL_VALID ||
 464                                                vl->state == AFS_VL_NO_VOLUME);
 465                 if (ret < 0)
 466                         goto error;
 467                 spin_lock(&vl->lock);
 468         }
 469         spin_unlock(&vl->lock);
 470
 471 success:
 472         _leave(" = %p", vl);
 473         return vl;
 474
 475 error_abandon:
 476         spin_lock(&vl->lock);
 477         vl->state = AFS_VL_NEW;
 478         spin_unlock(&vl->lock);
 479         wake_up(&vl->waitq);
 480 error:
 481         ASSERT(vl != NULL);
 482         afs_put_vlocation(vl);
 483         _leave(" = %d", ret);
 484         return ERR_PTR(ret);
 485 }
 486
 487 /*
 488  * finish using a volume location record
 489  */
 490 void afs_put_vlocation(struct afs_vlocation *vl)
 491 {
 492         if (!vl)
 493                 return;
 494
 495         _enter("%s", vl->vldb.name);
 496
 497         ASSERTCMP(atomic_read(&vl->usage), >, 0);
 498
 499         if (likely(!atomic_dec_and_test(&vl->usage))) {
 500                 _leave("");
 501                 return;
 502         }
 503
 504         spin_lock(&afs_vlocation_graveyard_lock);
 505         if (atomic_read(&vl->usage) == 0) {
 506                 _debug("buried");
 507                 list_move_tail(&vl->grave, &afs_vlocation_graveyard);
 508                 vl->time_of_death = get_seconds();
 509                 schedule_delayed_work(&afs_vlocation_reap,
 510                                       afs_vlocation_timeout * HZ);
 511
 512                 /* suspend updates on this record */
 513                 if (!list_empty(&vl->update)) {
 514                         spin_lock(&afs_vlocation_updates_lock);
 515                         list_del_init(&vl->update);
 516                         spin_unlock(&afs_vlocation_updates_lock);
 517                 }
 518         }
 519         spin_unlock(&afs_vlocation_graveyard_lock);
 520         _leave(" [killed?]");
 521 }
 522
 523 /*
 524  * destroy a dead volume location record
 525  */
 526 static void afs_vlocation_destroy(struct afs_vlocation *vl)
 527 {
 528         _enter("%p", vl);
 529
 530 #ifdef CONFIG_AFS_FSCACHE
 531         fscache_relinquish_cookie(vl->cache, 0);
 532 #endif
 533         afs_put_cell(vl->cell);
 534         kfree(vl);
 535 }
 536
 537 /*
 538  * reap dead volume location records
 539  */
 540 static void afs_vlocation_reaper(struct work_struct *work)
 541 {
 542         LIST_HEAD(corpses);
 543         struct afs_vlocation *vl;
 544         unsigned long delay, expiry;
 545         time_t now;
 546
 547         _enter("");
 548
 549         now = get_seconds();
 550         spin_lock(&afs_vlocation_graveyard_lock);
 551
 552         while (!list_empty(&afs_vlocation_graveyard)) {
 553                 vl = list_entry(afs_vlocation_graveyard.next,
 554                                 struct afs_vlocation, grave);
 555
 556                 _debug("check %p", vl);
 557
 558                 /* the queue is ordered most dead first */
 559                 expiry = vl->time_of_death + afs_vlocation_timeout;
 560                 if (expiry > now) {
 561                         delay = (expiry - now) * HZ;
 562                         _debug("delay %lu", delay);
 563                         if (!schedule_delayed_work(&afs_vlocation_reap,
 564                                                    delay)) {
 565                                 cancel_delayed_work(&afs_vlocation_reap);
 566                                 schedule_delayed_work(&afs_vlocation_reap,
 567                                                       delay);
 568                         }
 569                         break;
 570                 }
 571
 572                 spin_lock(&vl->cell->vl_lock);
 573                 if (atomic_read(&vl->usage) > 0) {
 574                         _debug("no reap");
 575                         list_del_init(&vl->grave);
 576                 } else {
 577                         _debug("reap");
 578                         list_move_tail(&vl->grave, &corpses);
 579                         list_del_init(&vl->link);
 580                 }
 581                 spin_unlock(&vl->cell->vl_lock);
 582         }
 583
 584         spin_unlock(&afs_vlocation_graveyard_lock);
 585
 586         /* now reap the corpses we've extracted */
 587         while (!list_empty(&corpses)) {
 588                 vl = list_entry(corpses.next, struct afs_vlocation, grave);
 589                 list_del(&vl->grave);
 590                 afs_vlocation_destroy(vl);
 591         }
 592
 593         _leave("");
 594 }
 595
 596 /*
 597  * initialise the VL update process
 598  */
 599 int __init afs_vlocation_update_init(void)
 600 {
 601         afs_vlocation_update_worker =
 602                 create_singlethread_workqueue("kafs_vlupdated");
 603         return afs_vlocation_update_worker ? 0 : -ENOMEM;
 604 }
 605
 606 /*
 607  * discard all the volume location records for rmmod
 608  */
 609 void afs_vlocation_purge(void)
 610 {
 611         afs_vlocation_timeout = 0;
 612
 613         spin_lock(&afs_vlocation_updates_lock);
 614         list_del_init(&afs_vlocation_updates);
 615         spin_unlock(&afs_vlocation_updates_lock);
 616         cancel_delayed_work(&afs_vlocation_update);
 617         queue_delayed_work(afs_vlocation_update_worker,
 618                            &afs_vlocation_update, 0);
 619         destroy_workqueue(afs_vlocation_update_worker);
 620
 621         cancel_delayed_work(&afs_vlocation_reap);
 622         schedule_delayed_work(&afs_vlocation_reap, 0);
 623 }
 624
 625 /*
 626  * update a volume location
 627  */
 628 static void afs_vlocation_updater(struct work_struct *work)
 629 {
 630         struct afs_cache_vlocation vldb;
 631         struct afs_vlocation *vl, *xvl;
 632         time_t now;
 633         long timeout;
 634         int ret;
 635
 636         _enter("");
 637
 638         now = get_seconds();
 639
 640         /* find a record to update */
 641         spin_lock(&afs_vlocation_updates_lock);
 642         for (;;) {
 643                 if (list_empty(&afs_vlocation_updates)) {
 644                         spin_unlock(&afs_vlocation_updates_lock);
 645                         _leave(" [nothing]");
 646                         return;
 647                 }
 648
 649                 vl = list_entry(afs_vlocation_updates.next,
 650                                 struct afs_vlocation, update);
 651                 if (atomic_read(&vl->usage) > 0)
 652                         break;
 653                 list_del_init(&vl->update);
 654         }
 655
 656         timeout = vl->update_at - now;
 657         if (timeout > 0) {
 658                 queue_delayed_work(afs_vlocation_update_worker,
 659                                    &afs_vlocation_update, timeout * HZ);
 660                 spin_unlock(&afs_vlocation_updates_lock);
 661                 _leave(" [nothing]");
 662                 return;
 663         }
 664
 665         list_del_init(&vl->update);
 666         atomic_inc(&vl->usage);
 667         spin_unlock(&afs_vlocation_updates_lock);
 668
 669         /* we can now perform the update */
 670         _debug("update %s", vl->vldb.name);
 671         vl->state = AFS_VL_UPDATING;
 672         vl->upd_rej_cnt = 0;
 673         vl->upd_busy_cnt = 0;
 674
 675         ret = afs_vlocation_update_record(vl, NULL, &vldb);
 676         spin_lock(&vl->lock);
 677         switch (ret) {
 678         case 0:
 679                 afs_vlocation_apply_update(vl, &vldb);
 680                 vl->state = AFS_VL_VALID;
 681                 break;
 682         case -ENOMEDIUM:
 683                 vl->state = AFS_VL_VOLUME_DELETED;
 684                 break;
 685         default:
 686                 vl->state = AFS_VL_UNCERTAIN;
 687                 break;
 688         }
 689         spin_unlock(&vl->lock);
 690         wake_up(&vl->waitq);
 691
 692         /* and then reschedule */
 693         _debug("reschedule");
 694         vl->update_at = get_seconds() + afs_vlocation_update_timeout;
 695
 696         spin_lock(&afs_vlocation_updates_lock);
 697
 698         if (!list_empty(&afs_vlocation_updates)) {
 699                 /* next update in 10 minutes, but wait at least 1 second more
 700                  * than the newest record already queued so that we don't spam
 701                  * the VL server suddenly with lots of requests
 702                  */
 703                 xvl = list_entry(afs_vlocation_updates.prev,
 704                                  struct afs_vlocation, update);
 705                 if (vl->update_at <= xvl->update_at)
 706                         vl->update_at = xvl->update_at + 1;
 707                 xvl = list_entry(afs_vlocation_updates.next,
 708                                  struct afs_vlocation, update);
 709                 timeout = xvl->update_at - now;
 710                 if (timeout < 0)
 711                         timeout = 0;
 712         } else {
 713                 timeout = afs_vlocation_update_timeout;
 714         }
 715
 716         ASSERT(list_empty(&vl->update));
 717
 718         list_add_tail(&vl->update, &afs_vlocation_updates);
 719
 720         _debug("timeout %ld", timeout);
 721         queue_delayed_work(afs_vlocation_update_worker,
 722                            &afs_vlocation_update, timeout * HZ);
 723         spin_unlock(&afs_vlocation_updates_lock);
 724         afs_put_vlocation(vl);
 725 }