fs/afs/server.c

   1 /* AFS server record 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/sched.h>
  13 #include <linux/slab.h>
  14 #include "afs_fs.h"
  15 #include "internal.h"
  16
  17 static unsigned afs_server_gc_delay = 10;       /* Server record timeout in seconds */
  18 static unsigned afs_server_update_delay = 30;   /* Time till VLDB recheck in secs */
  19
  20 static void afs_inc_servers_outstanding(struct afs_net *net)
  21 {
  22         atomic_inc(&net->servers_outstanding);
  23 }
  24
  25 static void afs_dec_servers_outstanding(struct afs_net *net)
  26 {
  27         if (atomic_dec_and_test(&net->servers_outstanding))
  28                 wake_up_var(&net->servers_outstanding);
  29 }
  30
  31 /*
  32  * Find a server by one of its addresses.
  33  */
  34 struct afs_server *afs_find_server(struct afs_net *net,
  35                                    const struct sockaddr_rxrpc *srx)
  36 {
  37         const struct sockaddr_in6 *a = &srx->transport.sin6, *b;
  38         const struct afs_addr_list *alist;
  39         struct afs_server *server = NULL;
  40         unsigned int i;
  41         bool ipv6 = true;
  42         int seq = 0, diff;
  43
  44         if (srx->transport.sin6.sin6_addr.s6_addr32[0] == 0 ||
  45             srx->transport.sin6.sin6_addr.s6_addr32[1] == 0 ||
  46             srx->transport.sin6.sin6_addr.s6_addr32[2] == htonl(0xffff))
  47                 ipv6 = false;
  48
  49         rcu_read_lock();
  50
  51         do {
  52                 if (server)
  53                         afs_put_server(net, server);
  54                 server = NULL;
  55                 read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
  56
  57                 if (ipv6) {
  58                         hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) {
  59                                 alist = rcu_dereference(server->addresses);
  60                                 for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
  61                                         b = &alist->addrs[i].transport.sin6;
  62                                         diff = ((u16 __force)a->sin6_port -
  63                                                 (u16 __force)b->sin6_port);
  64                                         if (diff == 0)
  65                                                 diff = memcmp(&a->sin6_addr,
  66                                                               &b->sin6_addr,
  67                                                               sizeof(struct in6_addr));
  68                                         if (diff == 0)
  69                                                 goto found;
  70                                 }
  71                         }
  72                 } else {
  73                         hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) {
  74                                 alist = rcu_dereference(server->addresses);
  75                                 for (i = 0; i < alist->nr_ipv4; i++) {
  76                                         b = &alist->addrs[i].transport.sin6;
  77                                         diff = ((u16 __force)a->sin6_port -
  78                                                 (u16 __force)b->sin6_port);
  79                                         if (diff == 0)
  80                                                 diff = ((u32 __force)a->sin6_addr.s6_addr32[3] -
  81                                                         (u32 __force)b->sin6_addr.s6_addr32[3]);
  82                                         if (diff == 0)
  83                                                 goto found;
  84                                 }
  85                         }
  86                 }
  87
  88                 server = NULL;
  89         found:
  90                 if (server && !atomic_inc_not_zero(&server->usage))
  91                         server = NULL;
  92
  93         } while (need_seqretry(&net->fs_addr_lock, seq));
  94
  95         done_seqretry(&net->fs_addr_lock, seq);
  96
  97         rcu_read_unlock();
  98         return server;
  99 }
 100
 101 /*
 102  * Look up a server by its UUID
 103  */
 104 struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
 105 {
 106         struct afs_server *server = NULL;
 107         struct rb_node *p;
 108         int diff, seq = 0;
 109
 110         _enter("%pU", uuid);
 111
 112         do {
 113                 /* Unfortunately, rbtree walking doesn't give reliable results
 114                  * under just the RCU read lock, so we have to check for
 115                  * changes.
 116                  */
 117                 if (server)
 118                         afs_put_server(net, server);
 119                 server = NULL;
 120
 121                 read_seqbegin_or_lock(&net->fs_lock, &seq);
 122
 123                 p = net->fs_servers.rb_node;
 124                 while (p) {
 125                         server = rb_entry(p, struct afs_server, uuid_rb);
 126
 127                         diff = memcmp(uuid, &server->uuid, sizeof(*uuid));
 128                         if (diff < 0) {
 129                                 p = p->rb_left;
 130                         } else if (diff > 0) {
 131                                 p = p->rb_right;
 132                         } else {
 133                                 afs_get_server(server);
 134                                 break;
 135                         }
 136
 137                         server = NULL;
 138                 }
 139         } while (need_seqretry(&net->fs_lock, seq));
 140
 141         done_seqretry(&net->fs_lock, seq);
 142
 143         _leave(" = %p", server);
 144         return server;
 145 }
 146
 147 /*
 148  * Install a server record in the namespace tree
 149  */
 150 static struct afs_server *afs_install_server(struct afs_net *net,
 151                                              struct afs_server *candidate)
 152 {
 153         const struct afs_addr_list *alist;
 154         struct afs_server *server;
 155         struct rb_node **pp, *p;
 156         int ret = -EEXIST, diff;
 157
 158         _enter("%p", candidate);
 159
 160         write_seqlock(&net->fs_lock);
 161
 162         /* Firstly install the server in the UUID lookup tree */
 163         pp = &net->fs_servers.rb_node;
 164         p = NULL;
 165         while (*pp) {
 166                 p = *pp;
 167                 _debug("- consider %p", p);
 168                 server = rb_entry(p, struct afs_server, uuid_rb);
 169                 diff = memcmp(&candidate->uuid, &server->uuid, sizeof(uuid_t));
 170                 if (diff < 0)
 171                         pp = &(*pp)->rb_left;
 172                 else if (diff > 0)
 173                         pp = &(*pp)->rb_right;
 174                 else
 175                         goto exists;
 176         }
 177
 178         server = candidate;
 179         rb_link_node(&server->uuid_rb, p, pp);
 180         rb_insert_color(&server->uuid_rb, &net->fs_servers);
 181         hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
 182
 183         write_seqlock(&net->fs_addr_lock);
 184         alist = rcu_dereference_protected(server->addresses,
 185                                           lockdep_is_held(&net->fs_addr_lock.lock));
 186
 187         /* Secondly, if the server has any IPv4 and/or IPv6 addresses, install
 188          * it in the IPv4 and/or IPv6 reverse-map lists.
 189          *
 190          * TODO: For speed we want to use something other than a flat list
 191          * here; even sorting the list in terms of lowest address would help a
 192          * bit, but anything we might want to do gets messy and memory
 193          * intensive.
 194          */
 195         if (alist->nr_ipv4 > 0)
 196                 hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4);
 197         if (alist->nr_addrs > alist->nr_ipv4)
 198                 hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6);
 199
 200         write_sequnlock(&net->fs_addr_lock);
 201         ret = 0;
 202
 203 exists:
 204         afs_get_server(server);
 205         write_sequnlock(&net->fs_lock);
 206         return server;
 207 }
 208
 209 /*
 210  * allocate a new server record
 211  */
 212 static struct afs_server *afs_alloc_server(struct afs_net *net,
 213                                            const uuid_t *uuid,
 214                                            struct afs_addr_list *alist)
 215 {
 216         struct afs_server *server;
 217
 218         _enter("");
 219
 220         server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
 221         if (!server)
 222                 goto enomem;
 223
 224         atomic_set(&server->usage, 1);
 225         RCU_INIT_POINTER(server->addresses, alist);
 226         server->addr_version = alist->version;
 227         server->uuid = *uuid;
 228         server->flags = (1UL << AFS_SERVER_FL_NEW);
 229         server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
 230         rwlock_init(&server->fs_lock);
 231         INIT_HLIST_HEAD(&server->cb_volumes);
 232         rwlock_init(&server->cb_break_lock);
 233
 234         afs_inc_servers_outstanding(net);
 235         _leave(" = %p", server);
 236         return server;
 237
 238 enomem:
 239         _leave(" = NULL [nomem]");
 240         return NULL;
 241 }
 242
 243 /*
 244  * Look up an address record for a server
 245  */
 246 static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
 247                                                  struct key *key, const uuid_t *uuid)
 248 {
 249         struct afs_addr_cursor ac;
 250         struct afs_addr_list *alist;
 251         int ret;
 252
 253         ret = afs_set_vl_cursor(&ac, cell);
 254         if (ret < 0)
 255                 return ERR_PTR(ret);
 256
 257         while (afs_iterate_addresses(&ac)) {
 258                 if (test_bit(ac.index, &ac.alist->yfs))
 259                         alist = afs_yfsvl_get_endpoints(cell->net, &ac, key, uuid);
 260                 else
 261                         alist = afs_vl_get_addrs_u(cell->net, &ac, key, uuid);
 262                 switch (ac.error) {
 263                 case 0:
 264                         afs_end_cursor(&ac);
 265                         return alist;
 266                 case -ECONNABORTED:
 267                         ac.error = afs_abort_to_error(ac.abort_code);
 268                         goto error;
 269                 case -ENOMEM:
 270                 case -ENONET:
 271                         goto error;
 272                 case -ENETUNREACH:
 273                 case -EHOSTUNREACH:
 274                 case -ECONNREFUSED:
 275                         break;
 276                 default:
 277                         ac.error = -EIO;
 278                         goto error;
 279                 }
 280         }
 281
 282 error:
 283         return ERR_PTR(afs_end_cursor(&ac));
 284 }
 285
 286 /*
 287  * Get or create a fileserver record.
 288  */
 289 struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
 290                                      const uuid_t *uuid)
 291 {
 292         struct afs_addr_list *alist;
 293         struct afs_server *server, *candidate;
 294
 295         _enter("%p,%pU", cell->net, uuid);
 296
 297         server = afs_find_server_by_uuid(cell->net, uuid);
 298         if (server)
 299                 return server;
 300
 301         alist = afs_vl_lookup_addrs(cell, key, uuid);
 302         if (IS_ERR(alist))
 303                 return ERR_CAST(alist);
 304
 305         candidate = afs_alloc_server(cell->net, uuid, alist);
 306         if (!candidate) {
 307                 afs_put_addrlist(alist);
 308                 return ERR_PTR(-ENOMEM);
 309         }
 310
 311         server = afs_install_server(cell->net, candidate);
 312         if (server != candidate) {
 313                 afs_put_addrlist(alist);
 314                 kfree(candidate);
 315         }
 316
 317         _leave(" = %p{%d}", server, atomic_read(&server->usage));
 318         return server;
 319 }
 320
 321 /*
 322  * Set the server timer to fire after a given delay, assuming it's not already
 323  * set for an earlier time.
 324  */
 325 static void afs_set_server_timer(struct afs_net *net, time64_t delay)
 326 {
 327         if (net->live) {
 328                 afs_inc_servers_outstanding(net);
 329                 if (timer_reduce(&net->fs_timer, jiffies + delay * HZ))
 330                         afs_dec_servers_outstanding(net);
 331         }
 332 }
 333
 334 /*
 335  * Server management timer.  We have an increment on fs_outstanding that we
 336  * need to pass along to the work item.
 337  */
 338 void afs_servers_timer(struct timer_list *timer)
 339 {
 340         struct afs_net *net = container_of(timer, struct afs_net, fs_timer);
 341
 342         _enter("");
 343         if (!queue_work(afs_wq, &net->fs_manager))
 344                 afs_dec_servers_outstanding(net);
 345 }
 346
 347 /*
 348  * Release a reference on a server record.
 349  */
 350 void afs_put_server(struct afs_net *net, struct afs_server *server)
 351 {
 352         unsigned int usage;
 353
 354         if (!server)
 355                 return;
 356
 357         server->put_time = ktime_get_real_seconds();
 358
 359         usage = atomic_dec_return(&server->usage);
 360
 361         _enter("{%u}", usage);
 362
 363         if (likely(usage > 0))
 364                 return;
 365
 366         afs_set_server_timer(net, afs_server_gc_delay);
 367 }
 368
 369 static void afs_server_rcu(struct rcu_head *rcu)
 370 {
 371         struct afs_server *server = container_of(rcu, struct afs_server, rcu);
 372
 373         afs_put_addrlist(rcu_access_pointer(server->addresses));
 374         kfree(server);
 375 }
 376
 377 /*
 378  * destroy a dead server
 379  */
 380 static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
 381 {
 382         struct afs_addr_list *alist = rcu_access_pointer(server->addresses);
 383         struct afs_addr_cursor ac = {
 384                 .alist  = alist,
 385                 .start  = alist->index,
 386                 .index  = 0,
 387                 .addr   = &alist->addrs[alist->index],
 388                 .error  = 0,
 389         };
 390         _enter("%p", server);
 391
 392         if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
 393                 afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
 394
 395         call_rcu(&server->rcu, afs_server_rcu);
 396         afs_dec_servers_outstanding(net);
 397 }
 398
 399 /*
 400  * Garbage collect any expired servers.
 401  */
 402 static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
 403 {
 404         struct afs_server *server;
 405         bool deleted;
 406         int usage;
 407
 408         while ((server = gc_list)) {
 409                 gc_list = server->gc_next;
 410
 411                 write_seqlock(&net->fs_lock);
 412                 usage = 1;
 413                 deleted = atomic_try_cmpxchg(&server->usage, &usage, 0);
 414                 if (deleted) {
 415                         rb_erase(&server->uuid_rb, &net->fs_servers);
 416                         hlist_del_rcu(&server->proc_link);
 417                 }
 418                 write_sequnlock(&net->fs_lock);
 419
 420                 if (deleted) {
 421                         write_seqlock(&net->fs_addr_lock);
 422                         if (!hlist_unhashed(&server->addr4_link))
 423                                 hlist_del_rcu(&server->addr4_link);
 424                         if (!hlist_unhashed(&server->addr6_link))
 425                                 hlist_del_rcu(&server->addr6_link);
 426                         write_sequnlock(&net->fs_addr_lock);
 427                         afs_destroy_server(net, server);
 428                 }
 429         }
 430 }
 431
 432 /*
 433  * Manage the records of servers known to be within a network namespace.  This
 434  * includes garbage collecting unused servers.
 435  *
 436  * Note also that we were given an increment on net->servers_outstanding by
 437  * whoever queued us that we need to deal with before returning.
 438  */
 439 void afs_manage_servers(struct work_struct *work)
 440 {
 441         struct afs_net *net = container_of(work, struct afs_net, fs_manager);
 442         struct afs_server *gc_list = NULL;
 443         struct rb_node *cursor;
 444         time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
 445         bool purging = !net->live;
 446
 447         _enter("");
 448
 449         /* Trawl the server list looking for servers that have expired from
 450          * lack of use.
 451          */
 452         read_seqlock_excl(&net->fs_lock);
 453
 454         for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
 455                 struct afs_server *server =
 456                         rb_entry(cursor, struct afs_server, uuid_rb);
 457                 int usage = atomic_read(&server->usage);
 458
 459                 _debug("manage %pU %u", &server->uuid, usage);
 460
 461                 ASSERTCMP(usage, >=, 1);
 462                 ASSERTIFCMP(purging, usage, ==, 1);
 463
 464                 if (usage == 1) {
 465                         time64_t expire_at = server->put_time;
 466
 467                         if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
 468                             !test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
 469                                 expire_at += afs_server_gc_delay;
 470                         if (purging || expire_at <= now) {
 471                                 server->gc_next = gc_list;
 472                                 gc_list = server;
 473                         } else if (expire_at < next_manage) {
 474                                 next_manage = expire_at;
 475                         }
 476                 }
 477         }
 478
 479         read_sequnlock_excl(&net->fs_lock);
 480
 481         /* Update the timer on the way out.  We have to pass an increment on
 482          * servers_outstanding in the namespace that we are in to the timer or
 483          * the work scheduler.
 484          */
 485         if (!purging && next_manage < TIME64_MAX) {
 486                 now = ktime_get_real_seconds();
 487
 488                 if (next_manage - now <= 0) {
 489                         if (queue_work(afs_wq, &net->fs_manager))
 490                                 afs_inc_servers_outstanding(net);
 491                 } else {
 492                         afs_set_server_timer(net, next_manage - now);
 493                 }
 494         }
 495
 496         afs_gc_servers(net, gc_list);
 497
 498         afs_dec_servers_outstanding(net);
 499         _leave(" [%d]", atomic_read(&net->servers_outstanding));
 500 }
 501
 502 static void afs_queue_server_manager(struct afs_net *net)
 503 {
 504         afs_inc_servers_outstanding(net);
 505         if (!queue_work(afs_wq, &net->fs_manager))
 506                 afs_dec_servers_outstanding(net);
 507 }
 508
 509 /*
 510  * Purge list of servers.
 511  */
 512 void afs_purge_servers(struct afs_net *net)
 513 {
 514         _enter("");
 515
 516         if (del_timer_sync(&net->fs_timer))
 517                 atomic_dec(&net->servers_outstanding);
 518
 519         afs_queue_server_manager(net);
 520
 521         _debug("wait");
 522         wait_var_event(&net->servers_outstanding,
 523                        !atomic_read(&net->servers_outstanding));
 524         _leave("");
 525 }
 526
 527 /*
 528  * Probe a fileserver to find its capabilities.
 529  *
 530  * TODO: Try service upgrade.
 531  */
 532 static bool afs_do_probe_fileserver(struct afs_fs_cursor *fc)
 533 {
 534         _enter("");
 535
 536         fc->ac.addr = NULL;
 537         fc->ac.start = READ_ONCE(fc->ac.alist->index);
 538         fc->ac.index = fc->ac.start;
 539         fc->ac.error = 0;
 540         fc->ac.begun = false;
 541
 542         while (afs_iterate_addresses(&fc->ac)) {
 543                 afs_fs_get_capabilities(afs_v2net(fc->vnode), fc->cbi->server,
 544                                         &fc->ac, fc->key);
 545                 switch (fc->ac.error) {
 546                 case 0:
 547                         afs_end_cursor(&fc->ac);
 548                         set_bit(AFS_SERVER_FL_PROBED, &fc->cbi->server->flags);
 549                         return true;
 550                 case -ECONNABORTED:
 551                         fc->ac.error = afs_abort_to_error(fc->ac.abort_code);
 552                         goto error;
 553                 case -ENOMEM:
 554                 case -ENONET:
 555                         goto error;
 556                 case -ENETUNREACH:
 557                 case -EHOSTUNREACH:
 558                 case -ECONNREFUSED:
 559                 case -ETIMEDOUT:
 560                 case -ETIME:
 561                         break;
 562                 default:
 563                         fc->ac.error = -EIO;
 564                         goto error;
 565                 }
 566         }
 567
 568 error:
 569         afs_end_cursor(&fc->ac);
 570         return false;
 571 }
 572
 573 /*
 574  * If we haven't already, try probing the fileserver to get its capabilities.
 575  * We try not to instigate parallel probes, but it's possible that the parallel
 576  * probes will fail due to authentication failure when ours would succeed.
 577  *
 578  * TODO: Try sending an anonymous probe if an authenticated probe fails.
 579  */
 580 bool afs_probe_fileserver(struct afs_fs_cursor *fc)
 581 {
 582         bool success;
 583         int ret, retries = 0;
 584
 585         _enter("");
 586
 587 retry:
 588         if (test_bit(AFS_SERVER_FL_PROBED, &fc->cbi->server->flags)) {
 589                 _leave(" = t");
 590                 return true;
 591         }
 592
 593         if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &fc->cbi->server->flags)) {
 594                 success = afs_do_probe_fileserver(fc);
 595                 clear_bit_unlock(AFS_SERVER_FL_PROBING, &fc->cbi->server->flags);
 596                 wake_up_bit(&fc->cbi->server->flags, AFS_SERVER_FL_PROBING);
 597                 _leave(" = t");
 598                 return success;
 599         }
 600
 601         _debug("wait");
 602         ret = wait_on_bit(&fc->cbi->server->flags, AFS_SERVER_FL_PROBING,
 603                           TASK_INTERRUPTIBLE);
 604         if (ret == -ERESTARTSYS) {
 605                 fc->ac.error = ret;
 606                 _leave(" = f [%d]", ret);
 607                 return false;
 608         }
 609
 610         retries++;
 611         if (retries == 4) {
 612                 fc->ac.error = -ESTALE;
 613                 _leave(" = f [stale]");
 614                 return false;
 615         }
 616         _debug("retry");
 617         goto retry;
 618 }
 619
 620 /*
 621  * Get an update for a server's address list.
 622  */
 623 static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
 624 {
 625         struct afs_addr_list *alist, *discard;
 626
 627         _enter("");
 628
 629         alist = afs_vl_lookup_addrs(fc->vnode->volume->cell, fc->key,
 630                                     &server->uuid);
 631         if (IS_ERR(alist)) {
 632                 fc->ac.error = PTR_ERR(alist);
 633                 _leave(" = f [%d]", fc->ac.error);
 634                 return false;
 635         }
 636
 637         discard = alist;
 638         if (server->addr_version != alist->version) {
 639                 write_lock(&server->fs_lock);
 640                 discard = rcu_dereference_protected(server->addresses,
 641                                                     lockdep_is_held(&server->fs_lock));
 642                 rcu_assign_pointer(server->addresses, alist);
 643                 server->addr_version = alist->version;
 644                 write_unlock(&server->fs_lock);
 645         }
 646
 647         server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
 648         afs_put_addrlist(discard);
 649         _leave(" = t");
 650         return true;
 651 }
 652
 653 /*
 654  * See if a server's address list needs updating.
 655  */
 656 bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
 657 {
 658         time64_t now = ktime_get_real_seconds();
 659         long diff;
 660         bool success;
 661         int ret, retries = 0;
 662
 663         _enter("");
 664
 665         ASSERT(server);
 666
 667 retry:
 668         diff = READ_ONCE(server->update_at) - now;
 669         if (diff > 0) {
 670                 _leave(" = t [not now %ld]", diff);
 671                 return true;
 672         }
 673
 674         if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) {
 675                 success = afs_update_server_record(fc, server);
 676                 clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags);
 677                 wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING);
 678                 _leave(" = %d", success);
 679                 return success;
 680         }
 681
 682         ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING,
 683                           TASK_INTERRUPTIBLE);
 684         if (ret == -ERESTARTSYS) {
 685                 fc->ac.error = ret;
 686                 _leave(" = f [intr]");
 687                 return false;
 688         }
 689
 690         retries++;
 691         if (retries == 4) {
 692                 _leave(" = f [stale]");
 693                 ret = -ESTALE;
 694                 return false;
 695         }
 696         goto retry;
 697 }