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