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

   1 /* cell.c: AFS cell and server record 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/module.h>
  13 #include <linux/slab.h>
  14 #include <rxrpc/peer.h>
  15 #include <rxrpc/connection.h>
  16 #include "volume.h"
  17 #include "cell.h"
  18 #include "server.h"
  19 #include "transport.h"
  20 #include "vlclient.h"
  21 #include "kafstimod.h"
  22 #include "super.h"
  23 #include "internal.h"
  24
  25 DECLARE_RWSEM(afs_proc_cells_sem);
  26 LIST_HEAD(afs_proc_cells);
  27
  28 static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells);
  29 static DEFINE_RWLOCK(afs_cells_lock);
  30 static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
  31 static struct afs_cell *afs_cell_root;
  32
  33 #ifdef AFS_CACHING_SUPPORT
  34 static cachefs_match_val_t afs_cell_cache_match(void *target,
  35                                                 const void *entry);
  36 static void afs_cell_cache_update(void *source, void *entry);
  37
  38 struct cachefs_index_def afs_cache_cell_index_def = {
  39         .name                   = "cell_ix",
  40         .data_size              = sizeof(struct afs_cache_cell),
  41         .keys[0]                = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 },
  42         .match                  = afs_cell_cache_match,
  43         .update                 = afs_cell_cache_update,
  44 };
  45 #endif
  46
  47 /*****************************************************************************/
  48 /*
  49  * create a cell record
  50  * - "name" is the name of the cell
  51  * - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format
  52  */
  53 int afs_cell_create(const char *name, char *vllist, struct afs_cell **_cell)
  54 {
  55         struct afs_cell *cell;
  56         char *next;
  57         int ret;
  58
  59         _enter("%s", name);
  60
  61         BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
  62
  63         /* allocate and initialise a cell record */
  64         cell = kmalloc(sizeof(struct afs_cell) + strlen(name) + 1, GFP_KERNEL);
  65         if (!cell) {
  66                 _leave(" = -ENOMEM");
  67                 return -ENOMEM;
  68         }
  69
  70         down_write(&afs_cells_sem);
  71
  72         memset(cell, 0, sizeof(struct afs_cell));
  73         atomic_set(&cell->usage, 0);
  74
  75         INIT_LIST_HEAD(&cell->link);
  76
  77         rwlock_init(&cell->sv_lock);
  78         INIT_LIST_HEAD(&cell->sv_list);
  79         INIT_LIST_HEAD(&cell->sv_graveyard);
  80         spin_lock_init(&cell->sv_gylock);
  81
  82         init_rwsem(&cell->vl_sem);
  83         INIT_LIST_HEAD(&cell->vl_list);
  84         INIT_LIST_HEAD(&cell->vl_graveyard);
  85         spin_lock_init(&cell->vl_gylock);
  86
  87         strcpy(cell->name,name);
  88
  89         /* fill in the VL server list from the rest of the string */
  90         ret = -EINVAL;
  91         do {
  92                 unsigned a, b, c, d;
  93
  94                 next = strchr(vllist, ':');
  95                 if (next)
  96                         *next++ = 0;
  97
  98                 if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
  99                         goto badaddr;
 100
 101                 if (a > 255 || b > 255 || c > 255 || d > 255)
 102                         goto badaddr;
 103
 104                 cell->vl_addrs[cell->vl_naddrs++].s_addr =
 105                         htonl((a << 24) | (b << 16) | (c << 8) | d);
 106
 107                 if (cell->vl_naddrs >= AFS_CELL_MAX_ADDRS)
 108                         break;
 109
 110         } while(vllist = next, vllist);
 111
 112         /* add a proc dir for this cell */
 113         ret = afs_proc_cell_setup(cell);
 114         if (ret < 0)
 115                 goto error;
 116
 117 #ifdef AFS_CACHING_SUPPORT
 118         /* put it up for caching */
 119         cachefs_acquire_cookie(afs_cache_netfs.primary_index,
 120                                &afs_vlocation_cache_index_def,
 121                                cell,
 122                                &cell->cache);
 123 #endif
 124
 125         /* add to the cell lists */
 126         write_lock(&afs_cells_lock);
 127         list_add_tail(&cell->link, &afs_cells);
 128         write_unlock(&afs_cells_lock);
 129
 130         down_write(&afs_proc_cells_sem);
 131         list_add_tail(&cell->proc_link, &afs_proc_cells);
 132         up_write(&afs_proc_cells_sem);
 133
 134         *_cell = cell;
 135         up_write(&afs_cells_sem);
 136
 137         _leave(" = 0 (%p)", cell);
 138         return 0;
 139
 140  badaddr:
 141         printk(KERN_ERR "kAFS: bad VL server IP address: '%s'\n", vllist);
 142  error:
 143         up_write(&afs_cells_sem);
 144         kfree(cell);
 145         _leave(" = %d", ret);
 146         return ret;
 147 } /* end afs_cell_create() */
 148
 149 /*****************************************************************************/
 150 /*
 151  * initialise the cell database from module parameters
 152  */
 153 int afs_cell_init(char *rootcell)
 154 {
 155         struct afs_cell *old_root, *new_root;
 156         char *cp;
 157         int ret;
 158
 159         _enter("");
 160
 161         if (!rootcell) {
 162                 /* module is loaded with no parameters, or built statically.
 163                  * - in the future we might initialize cell DB here.
 164                  */
 165                 _leave(" = 0 (but no root)");
 166                 return 0;
 167         }
 168
 169         cp = strchr(rootcell, ':');
 170         if (!cp) {
 171                 printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
 172                 _leave(" = %d (no colon)", -EINVAL);
 173                 return -EINVAL;
 174         }
 175
 176         /* allocate a cell record for the root cell */
 177         *cp++ = 0;
 178         ret = afs_cell_create(rootcell, cp, &new_root);
 179         if (ret < 0) {
 180                 _leave(" = %d", ret);
 181                 return ret;
 182         }
 183
 184         /* as afs_put_cell() takes locks by itself, we have to do
 185          * a little gymnastics to be race-free.
 186          */
 187         afs_get_cell(new_root);
 188
 189         write_lock(&afs_cells_lock);
 190         while (afs_cell_root) {
 191                 old_root = afs_cell_root;
 192                 afs_cell_root = NULL;
 193                 write_unlock(&afs_cells_lock);
 194                 afs_put_cell(old_root);
 195                 write_lock(&afs_cells_lock);
 196         }
 197         afs_cell_root = new_root;
 198         write_unlock(&afs_cells_lock);
 199
 200         _leave(" = %d", ret);
 201         return ret;
 202
 203 } /* end afs_cell_init() */
 204
 205 /*****************************************************************************/
 206 /*
 207  * lookup a cell record
 208  */
 209 int afs_cell_lookup(const char *name, unsigned namesz, struct afs_cell **_cell)
 210 {
 211         struct afs_cell *cell;
 212         int ret;
 213
 214         _enter("\"%*.*s\",", namesz, namesz, name ? name : "");
 215
 216         *_cell = NULL;
 217
 218         if (name) {
 219                 /* if the cell was named, look for it in the cell record list */
 220                 ret = -ENOENT;
 221                 cell = NULL;
 222                 read_lock(&afs_cells_lock);
 223
 224                 list_for_each_entry(cell, &afs_cells, link) {
 225                         if (strncmp(cell->name, name, namesz) == 0) {
 226                                 afs_get_cell(cell);
 227                                 goto found;
 228                         }
 229                 }
 230                 cell = NULL;
 231         found:
 232
 233                 read_unlock(&afs_cells_lock);
 234
 235                 if (cell)
 236                         ret = 0;
 237         }
 238         else {
 239                 read_lock(&afs_cells_lock);
 240
 241                 cell = afs_cell_root;
 242                 if (!cell) {
 243                         /* this should not happen unless user tries to mount
 244                          * when root cell is not set. Return an impossibly
 245                          * bizzare errno to alert the user. Things like
 246                          * ENOENT might be "more appropriate" but they happen
 247                          * for other reasons.
 248                          */
 249                         ret = -EDESTADDRREQ;
 250                 }
 251                 else {
 252                         afs_get_cell(cell);
 253                         ret = 0;
 254                 }
 255
 256                 read_unlock(&afs_cells_lock);
 257         }
 258
 259         *_cell = cell;
 260         _leave(" = %d (%p)", ret, cell);
 261         return ret;
 262
 263 } /* end afs_cell_lookup() */
 264
 265 /*****************************************************************************/
 266 /*
 267  * try and get a cell record
 268  */
 269 struct afs_cell *afs_get_cell_maybe(struct afs_cell **_cell)
 270 {
 271         struct afs_cell *cell;
 272
 273         write_lock(&afs_cells_lock);
 274
 275         cell = *_cell;
 276         if (cell && !list_empty(&cell->link))
 277                 afs_get_cell(cell);
 278         else
 279                 cell = NULL;
 280
 281         write_unlock(&afs_cells_lock);
 282
 283         return cell;
 284 } /* end afs_get_cell_maybe() */
 285
 286 /*****************************************************************************/
 287 /*
 288  * destroy a cell record
 289  */
 290 void afs_put_cell(struct afs_cell *cell)
 291 {
 292         if (!cell)
 293                 return;
 294
 295         _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
 296
 297         /* sanity check */
 298         BUG_ON(atomic_read(&cell->usage) <= 0);
 299
 300         /* to prevent a race, the decrement and the dequeue must be effectively
 301          * atomic */
 302         write_lock(&afs_cells_lock);
 303
 304         if (likely(!atomic_dec_and_test(&cell->usage))) {
 305                 write_unlock(&afs_cells_lock);
 306                 _leave("");
 307                 return;
 308         }
 309
 310         write_unlock(&afs_cells_lock);
 311
 312         BUG_ON(!list_empty(&cell->sv_list));
 313         BUG_ON(!list_empty(&cell->sv_graveyard));
 314         BUG_ON(!list_empty(&cell->vl_list));
 315         BUG_ON(!list_empty(&cell->vl_graveyard));
 316
 317         _leave(" [unused]");
 318 } /* end afs_put_cell() */
 319
 320 /*****************************************************************************/
 321 /*
 322  * destroy a cell record
 323  */
 324 static void afs_cell_destroy(struct afs_cell *cell)
 325 {
 326         _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
 327
 328         /* to prevent a race, the decrement and the dequeue must be effectively
 329          * atomic */
 330         write_lock(&afs_cells_lock);
 331
 332         /* sanity check */
 333         BUG_ON(atomic_read(&cell->usage) != 0);
 334
 335         list_del_init(&cell->link);
 336
 337         write_unlock(&afs_cells_lock);
 338
 339         down_write(&afs_cells_sem);
 340
 341         afs_proc_cell_remove(cell);
 342
 343         down_write(&afs_proc_cells_sem);
 344         list_del_init(&cell->proc_link);
 345         up_write(&afs_proc_cells_sem);
 346
 347 #ifdef AFS_CACHING_SUPPORT
 348         cachefs_relinquish_cookie(cell->cache, 0);
 349 #endif
 350
 351         up_write(&afs_cells_sem);
 352
 353         BUG_ON(!list_empty(&cell->sv_list));
 354         BUG_ON(!list_empty(&cell->sv_graveyard));
 355         BUG_ON(!list_empty(&cell->vl_list));
 356         BUG_ON(!list_empty(&cell->vl_graveyard));
 357
 358         /* finish cleaning up the cell */
 359         kfree(cell);
 360
 361         _leave(" [destroyed]");
 362 } /* end afs_cell_destroy() */
 363
 364 /*****************************************************************************/
 365 /*
 366  * lookup the server record corresponding to an Rx RPC peer
 367  */
 368 int afs_server_find_by_peer(const struct rxrpc_peer *peer,
 369                             struct afs_server **_server)
 370 {
 371         struct afs_server *server;
 372         struct afs_cell *cell;
 373
 374         _enter("%p{a=%08x},", peer, ntohl(peer->addr.s_addr));
 375
 376         /* search the cell list */
 377         read_lock(&afs_cells_lock);
 378
 379         list_for_each_entry(cell, &afs_cells, link) {
 380
 381                 _debug("? cell %s",cell->name);
 382
 383                 write_lock(&cell->sv_lock);
 384
 385                 /* check the active list */
 386                 list_for_each_entry(server, &cell->sv_list, link) {
 387                         _debug("?? server %08x", ntohl(server->addr.s_addr));
 388
 389                         if (memcmp(&server->addr, &peer->addr,
 390                                    sizeof(struct in_addr)) == 0)
 391                                 goto found_server;
 392                 }
 393
 394                 /* check the inactive list */
 395                 spin_lock(&cell->sv_gylock);
 396                 list_for_each_entry(server, &cell->sv_graveyard, link) {
 397                         _debug("?? dead server %08x",
 398                                ntohl(server->addr.s_addr));
 399
 400                         if (memcmp(&server->addr, &peer->addr,
 401                                    sizeof(struct in_addr)) == 0)
 402                                 goto found_dead_server;
 403                 }
 404                 spin_unlock(&cell->sv_gylock);
 405
 406                 write_unlock(&cell->sv_lock);
 407         }
 408         read_unlock(&afs_cells_lock);
 409
 410         _leave(" = -ENOENT");
 411         return -ENOENT;
 412
 413         /* we found it in the graveyard - resurrect it */
 414  found_dead_server:
 415         list_move_tail(&server->link, &cell->sv_list);
 416         afs_get_server(server);
 417         afs_kafstimod_del_timer(&server->timeout);
 418         spin_unlock(&cell->sv_gylock);
 419         goto success;
 420
 421         /* we found it - increment its ref count and return it */
 422  found_server:
 423         afs_get_server(server);
 424
 425  success:
 426         write_unlock(&cell->sv_lock);
 427         read_unlock(&afs_cells_lock);
 428
 429         *_server = server;
 430         _leave(" = 0 (s=%p c=%p)", server, cell);
 431         return 0;
 432
 433 } /* end afs_server_find_by_peer() */
 434
 435 /*****************************************************************************/
 436 /*
 437  * purge in-memory cell database on module unload or afs_init() failure
 438  * - the timeout daemon is stopped before calling this
 439  */
 440 void afs_cell_purge(void)
 441 {
 442         struct afs_vlocation *vlocation;
 443         struct afs_cell *cell;
 444
 445         _enter("");
 446
 447         afs_put_cell(afs_cell_root);
 448
 449         while (!list_empty(&afs_cells)) {
 450                 cell = NULL;
 451
 452                 /* remove the next cell from the front of the list */
 453                 write_lock(&afs_cells_lock);
 454
 455                 if (!list_empty(&afs_cells)) {
 456                         cell = list_entry(afs_cells.next,
 457                                           struct afs_cell, link);
 458                         list_del_init(&cell->link);
 459                 }
 460
 461                 write_unlock(&afs_cells_lock);
 462
 463                 if (cell) {
 464                         _debug("PURGING CELL %s (%d)",
 465                                cell->name, atomic_read(&cell->usage));
 466
 467                         BUG_ON(!list_empty(&cell->sv_list));
 468                         BUG_ON(!list_empty(&cell->vl_list));
 469
 470                         /* purge the cell's VL graveyard list */
 471                         _debug(" - clearing VL graveyard");
 472
 473                         spin_lock(&cell->vl_gylock);
 474
 475                         while (!list_empty(&cell->vl_graveyard)) {
 476                                 vlocation = list_entry(cell->vl_graveyard.next,
 477                                                        struct afs_vlocation,
 478                                                        link);
 479                                 list_del_init(&vlocation->link);
 480
 481                                 afs_kafstimod_del_timer(&vlocation->timeout);
 482
 483                                 spin_unlock(&cell->vl_gylock);
 484
 485                                 afs_vlocation_do_timeout(vlocation);
 486                                 /* TODO: race if move to use krxtimod instead
 487                                  * of kafstimod */
 488
 489                                 spin_lock(&cell->vl_gylock);
 490                         }
 491
 492                         spin_unlock(&cell->vl_gylock);
 493
 494                         /* purge the cell's server graveyard list */
 495                         _debug(" - clearing server graveyard");
 496
 497                         spin_lock(&cell->sv_gylock);
 498
 499                         while (!list_empty(&cell->sv_graveyard)) {
 500                                 struct afs_server *server;
 501
 502                                 server = list_entry(cell->sv_graveyard.next,
 503                                                     struct afs_server, link);
 504                                 list_del_init(&server->link);
 505
 506                                 afs_kafstimod_del_timer(&server->timeout);
 507
 508                                 spin_unlock(&cell->sv_gylock);
 509
 510                                 afs_server_do_timeout(server);
 511
 512                                 spin_lock(&cell->sv_gylock);
 513                         }
 514
 515                         spin_unlock(&cell->sv_gylock);
 516
 517                         /* now the cell should be left with no references */
 518                         afs_cell_destroy(cell);
 519                 }
 520         }
 521
 522         _leave("");
 523 } /* end afs_cell_purge() */
 524
 525 /*****************************************************************************/
 526 /*
 527  * match a cell record obtained from the cache
 528  */
 529 #ifdef AFS_CACHING_SUPPORT
 530 static cachefs_match_val_t afs_cell_cache_match(void *target,
 531                                                 const void *entry)
 532 {
 533         const struct afs_cache_cell *ccell = entry;
 534         struct afs_cell *cell = target;
 535
 536         _enter("{%s},{%s}", ccell->name, cell->name);
 537
 538         if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) {
 539                 _leave(" = SUCCESS");
 540                 return CACHEFS_MATCH_SUCCESS;
 541         }
 542
 543         _leave(" = FAILED");
 544         return CACHEFS_MATCH_FAILED;
 545 } /* end afs_cell_cache_match() */
 546 #endif
 547
 548 /*****************************************************************************/
 549 /*
 550  * update a cell record in the cache
 551  */
 552 #ifdef AFS_CACHING_SUPPORT
 553 static void afs_cell_cache_update(void *source, void *entry)
 554 {
 555         struct afs_cache_cell *ccell = entry;
 556         struct afs_cell *cell = source;
 557
 558         _enter("%p,%p", source, entry);
 559
 560         strncpy(ccell->name, cell->name, sizeof(ccell->name));
 561
 562         memcpy(ccell->vl_servers,
 563                cell->vl_addrs,
 564                min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs)));
 565
 566 } /* end afs_cell_cache_update() */
 567 #endif