fs/afs/super.c

   1 /* AFS superblock handling
   2  *
   3  * Copyright (c) 2002, 2007, 2018 Red Hat, Inc. All rights reserved.
   4  *
   5  * This software may be freely redistributed under the terms of the
   6  * GNU General Public License.
   7  *
   8  * You should have received a copy of the GNU General Public License
   9  * along with this program; if not, write to the Free Software
  10  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  11  *
  12  * Authors: David Howells <dhowells@redhat.com>
  13  *          David Woodhouse <dwmw2@infradead.org>
  14  *
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/mount.h>
  20 #include <linux/init.h>
  21 #include <linux/slab.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/fs_parser.h>
  25 #include <linux/statfs.h>
  26 #include <linux/sched.h>
  27 #include <linux/nsproxy.h>
  28 #include <linux/magic.h>
  29 #include <net/net_namespace.h>
  30 #include "internal.h"
  31
  32 static void afs_i_init_once(void *foo);
  33 static void afs_kill_super(struct super_block *sb);
  34 static struct inode *afs_alloc_inode(struct super_block *sb);
  35 static void afs_destroy_inode(struct inode *inode);
  36 static void afs_free_inode(struct inode *inode);
  37 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  38 static int afs_show_devname(struct seq_file *m, struct dentry *root);
  39 static int afs_show_options(struct seq_file *m, struct dentry *root);
  40 static int afs_init_fs_context(struct fs_context *fc);
  41 static const struct fs_parameter_description afs_fs_parameters;
  42
  43 struct file_system_type afs_fs_type = {
  44         .owner                  = THIS_MODULE,
  45         .name                   = "afs",
  46         .init_fs_context        = afs_init_fs_context,
  47         .parameters             = &afs_fs_parameters,
  48         .kill_sb                = afs_kill_super,
  49         .fs_flags               = 0,
  50 };
  51 MODULE_ALIAS_FS("afs");
  52
  53 int afs_net_id;
  54
  55 static const struct super_operations afs_super_ops = {
  56         .statfs         = afs_statfs,
  57         .alloc_inode    = afs_alloc_inode,
  58         .drop_inode     = afs_drop_inode,
  59         .destroy_inode  = afs_destroy_inode,
  60         .free_inode     = afs_free_inode,
  61         .evict_inode    = afs_evict_inode,
  62         .show_devname   = afs_show_devname,
  63         .show_options   = afs_show_options,
  64 };
  65
  66 static struct kmem_cache *afs_inode_cachep;
  67 static atomic_t afs_count_active_inodes;
  68
  69 enum afs_param {
  70         Opt_autocell,
  71         Opt_dyn,
  72         Opt_source,
  73 };
  74
  75 static const struct fs_parameter_spec afs_param_specs[] = {
  76         fsparam_flag  ("autocell",      Opt_autocell),
  77         fsparam_flag  ("dyn",           Opt_dyn),
  78         fsparam_string("source",        Opt_source),
  79         {}
  80 };
  81
  82 static const struct fs_parameter_description afs_fs_parameters = {
  83         .name           = "kAFS",
  84         .specs          = afs_param_specs,
  85 };
  86
  87 /*
  88  * initialise the filesystem
  89  */
  90 int __init afs_fs_init(void)
  91 {
  92         int ret;
  93
  94         _enter("");
  95
  96         /* create ourselves an inode cache */
  97         atomic_set(&afs_count_active_inodes, 0);
  98
  99         ret = -ENOMEM;
 100         afs_inode_cachep = kmem_cache_create("afs_inode_cache",
 101                                              sizeof(struct afs_vnode),
 102                                              0,
 103                                              SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
 104                                              afs_i_init_once);
 105         if (!afs_inode_cachep) {
 106                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
 107                 return ret;
 108         }
 109
 110         /* now export our filesystem to lesser mortals */
 111         ret = register_filesystem(&afs_fs_type);
 112         if (ret < 0) {
 113                 kmem_cache_destroy(afs_inode_cachep);
 114                 _leave(" = %d", ret);
 115                 return ret;
 116         }
 117
 118         _leave(" = 0");
 119         return 0;
 120 }
 121
 122 /*
 123  * clean up the filesystem
 124  */
 125 void afs_fs_exit(void)
 126 {
 127         _enter("");
 128
 129         afs_mntpt_kill_timer();
 130         unregister_filesystem(&afs_fs_type);
 131
 132         if (atomic_read(&afs_count_active_inodes) != 0) {
 133                 printk("kAFS: %d active inode objects still present\n",
 134                        atomic_read(&afs_count_active_inodes));
 135                 BUG();
 136         }
 137
 138         /*
 139          * Make sure all delayed rcu free inodes are flushed before we
 140          * destroy cache.
 141          */
 142         rcu_barrier();
 143         kmem_cache_destroy(afs_inode_cachep);
 144         _leave("");
 145 }
 146
 147 /*
 148  * Display the mount device name in /proc/mounts.
 149  */
 150 static int afs_show_devname(struct seq_file *m, struct dentry *root)
 151 {
 152         struct afs_super_info *as = AFS_FS_S(root->d_sb);
 153         struct afs_volume *volume = as->volume;
 154         struct afs_cell *cell = as->cell;
 155         const char *suf = "";
 156         char pref = '%';
 157
 158         if (as->dyn_root) {
 159                 seq_puts(m, "none");
 160                 return 0;
 161         }
 162
 163         switch (volume->type) {
 164         case AFSVL_RWVOL:
 165                 break;
 166         case AFSVL_ROVOL:
 167                 pref = '#';
 168                 if (volume->type_force)
 169                         suf = ".readonly";
 170                 break;
 171         case AFSVL_BACKVOL:
 172                 pref = '#';
 173                 suf = ".backup";
 174                 break;
 175         }
 176
 177         seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
 178         return 0;
 179 }
 180
 181 /*
 182  * Display the mount options in /proc/mounts.
 183  */
 184 static int afs_show_options(struct seq_file *m, struct dentry *root)
 185 {
 186         struct afs_super_info *as = AFS_FS_S(root->d_sb);
 187
 188         if (as->dyn_root)
 189                 seq_puts(m, ",dyn");
 190         if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
 191                 seq_puts(m, ",autocell");
 192         return 0;
 193 }
 194
 195 /*
 196  * Parse the source name to get cell name, volume name, volume type and R/W
 197  * selector.
 198  *
 199  * This can be one of the following:
 200  *      "%[cell:]volume[.]"             R/W volume
 201  *      "#[cell:]volume[.]"             R/O or R/W volume (R/O parent),
 202  *                                       or R/W (R/W parent) volume
 203  *      "%[cell:]volume.readonly"       R/O volume
 204  *      "#[cell:]volume.readonly"       R/O volume
 205  *      "%[cell:]volume.backup"         Backup volume
 206  *      "#[cell:]volume.backup"         Backup volume
 207  */
 208 static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
 209 {
 210         struct afs_fs_context *ctx = fc->fs_private;
 211         struct afs_cell *cell;
 212         const char *cellname, *suffix, *name = param->string;
 213         int cellnamesz;
 214
 215         _enter(",%s", name);
 216
 217         if (!name) {
 218                 printk(KERN_ERR "kAFS: no volume name specified\n");
 219                 return -EINVAL;
 220         }
 221
 222         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 223                 /* To use dynroot, we don't want to have to provide a source */
 224                 if (strcmp(name, "none") == 0) {
 225                         ctx->no_cell = true;
 226                         return 0;
 227                 }
 228                 printk(KERN_ERR "kAFS: unparsable volume name\n");
 229                 return -EINVAL;
 230         }
 231
 232         /* determine the type of volume we're looking for */
 233         if (name[0] == '%') {
 234                 ctx->type = AFSVL_RWVOL;
 235                 ctx->force = true;
 236         }
 237         name++;
 238
 239         /* split the cell name out if there is one */
 240         ctx->volname = strchr(name, ':');
 241         if (ctx->volname) {
 242                 cellname = name;
 243                 cellnamesz = ctx->volname - name;
 244                 ctx->volname++;
 245         } else {
 246                 ctx->volname = name;
 247                 cellname = NULL;
 248                 cellnamesz = 0;
 249         }
 250
 251         /* the volume type is further affected by a possible suffix */
 252         suffix = strrchr(ctx->volname, '.');
 253         if (suffix) {
 254                 if (strcmp(suffix, ".readonly") == 0) {
 255                         ctx->type = AFSVL_ROVOL;
 256                         ctx->force = true;
 257                 } else if (strcmp(suffix, ".backup") == 0) {
 258                         ctx->type = AFSVL_BACKVOL;
 259                         ctx->force = true;
 260                 } else if (suffix[1] == 0) {
 261                 } else {
 262                         suffix = NULL;
 263                 }
 264         }
 265
 266         ctx->volnamesz = suffix ?
 267                 suffix - ctx->volname : strlen(ctx->volname);
 268
 269         _debug("cell %*.*s [%p]",
 270                cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
 271
 272         /* lookup the cell record */
 273         if (cellname) {
 274                 cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
 275                                        NULL, false);
 276                 if (IS_ERR(cell)) {
 277                         pr_err("kAFS: unable to lookup cell '%*.*s'\n",
 278                                cellnamesz, cellnamesz, cellname ?: "");
 279                         return PTR_ERR(cell);
 280                 }
 281                 afs_put_cell(ctx->net, ctx->cell);
 282                 ctx->cell = cell;
 283         }
 284
 285         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 286                ctx->cell->name, ctx->cell,
 287                ctx->volnamesz, ctx->volnamesz, ctx->volname,
 288                suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
 289
 290         fc->source = param->string;
 291         param->string = NULL;
 292         return 0;
 293 }
 294
 295 /*
 296  * Parse a single mount parameter.
 297  */
 298 static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 299 {
 300         struct fs_parse_result result;
 301         struct afs_fs_context *ctx = fc->fs_private;
 302         int opt;
 303
 304         opt = fs_parse(fc, &afs_fs_parameters, param, &result);
 305         if (opt < 0)
 306                 return opt;
 307
 308         switch (opt) {
 309         case Opt_source:
 310                 return afs_parse_source(fc, param);
 311
 312         case Opt_autocell:
 313                 ctx->autocell = true;
 314                 break;
 315
 316         case Opt_dyn:
 317                 ctx->dyn_root = true;
 318                 break;
 319
 320         default:
 321                 return -EINVAL;
 322         }
 323
 324         _leave(" = 0");
 325         return 0;
 326 }
 327
 328 /*
 329  * Validate the options, get the cell key and look up the volume.
 330  */
 331 static int afs_validate_fc(struct fs_context *fc)
 332 {
 333         struct afs_fs_context *ctx = fc->fs_private;
 334         struct afs_volume *volume;
 335         struct key *key;
 336
 337         if (!ctx->dyn_root) {
 338                 if (ctx->no_cell) {
 339                         pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
 340                         return -EINVAL;
 341                 }
 342
 343                 if (!ctx->cell) {
 344                         pr_warn("kAFS: No cell specified\n");
 345                         return -EDESTADDRREQ;
 346                 }
 347
 348                 /* We try to do the mount securely. */
 349                 key = afs_request_key(ctx->cell);
 350                 if (IS_ERR(key))
 351                         return PTR_ERR(key);
 352
 353                 ctx->key = key;
 354
 355                 if (ctx->volume) {
 356                         afs_put_volume(ctx->cell, ctx->volume);
 357                         ctx->volume = NULL;
 358                 }
 359
 360                 volume = afs_create_volume(ctx);
 361                 if (IS_ERR(volume))
 362                         return PTR_ERR(volume);
 363
 364                 ctx->volume = volume;
 365         }
 366
 367         return 0;
 368 }
 369
 370 /*
 371  * check a superblock to see if it's the one we're looking for
 372  */
 373 static int afs_test_super(struct super_block *sb, struct fs_context *fc)
 374 {
 375         struct afs_fs_context *ctx = fc->fs_private;
 376         struct afs_super_info *as = AFS_FS_S(sb);
 377
 378         return (as->net_ns == fc->net_ns &&
 379                 as->volume &&
 380                 as->volume->vid == ctx->volume->vid &&
 381                 !as->dyn_root);
 382 }
 383
 384 static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
 385 {
 386         struct afs_super_info *as = AFS_FS_S(sb);
 387
 388         return (as->net_ns == fc->net_ns &&
 389                 as->dyn_root);
 390 }
 391
 392 static int afs_set_super(struct super_block *sb, struct fs_context *fc)
 393 {
 394         return set_anon_super(sb, NULL);
 395 }
 396
 397 /*
 398  * fill in the superblock
 399  */
 400 static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
 401 {
 402         struct afs_super_info *as = AFS_FS_S(sb);
 403         struct afs_fid fid;
 404         struct inode *inode = NULL;
 405         int ret;
 406
 407         _enter("");
 408
 409         /* fill in the superblock */
 410         sb->s_blocksize         = PAGE_SIZE;
 411         sb->s_blocksize_bits    = PAGE_SHIFT;
 412         sb->s_magic             = AFS_FS_MAGIC;
 413         sb->s_op                = &afs_super_ops;
 414         if (!as->dyn_root)
 415                 sb->s_xattr     = afs_xattr_handlers;
 416         ret = super_setup_bdi(sb);
 417         if (ret)
 418                 return ret;
 419         sb->s_bdi->ra_pages     = VM_READAHEAD_PAGES;
 420
 421         /* allocate the root inode and dentry */
 422         if (as->dyn_root) {
 423                 inode = afs_iget_pseudo_dir(sb, true);
 424                 sb->s_flags     |= SB_RDONLY;
 425         } else {
 426                 sprintf(sb->s_id, "%llu", as->volume->vid);
 427                 afs_activate_volume(as->volume);
 428                 fid.vid         = as->volume->vid;
 429                 fid.vnode       = 1;
 430                 fid.vnode_hi    = 0;
 431                 fid.unique      = 1;
 432                 inode = afs_iget(sb, ctx->key, &fid, NULL, NULL, NULL);
 433         }
 434
 435         if (IS_ERR(inode))
 436                 return PTR_ERR(inode);
 437
 438         if (ctx->autocell || as->dyn_root)
 439                 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 440
 441         ret = -ENOMEM;
 442         sb->s_root = d_make_root(inode);
 443         if (!sb->s_root)
 444                 goto error;
 445
 446         if (as->dyn_root) {
 447                 sb->s_d_op = &afs_dynroot_dentry_operations;
 448                 ret = afs_dynroot_populate(sb);
 449                 if (ret < 0)
 450                         goto error;
 451         } else {
 452                 sb->s_d_op = &afs_fs_dentry_operations;
 453         }
 454
 455         _leave(" = 0");
 456         return 0;
 457
 458 error:
 459         _leave(" = %d", ret);
 460         return ret;
 461 }
 462
 463 static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
 464 {
 465         struct afs_fs_context *ctx = fc->fs_private;
 466         struct afs_super_info *as;
 467
 468         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 469         if (as) {
 470                 as->net_ns = get_net(fc->net_ns);
 471                 if (ctx->dyn_root) {
 472                         as->dyn_root = true;
 473                 } else {
 474                         as->cell = afs_get_cell(ctx->cell);
 475                         as->volume = __afs_get_volume(ctx->volume);
 476                 }
 477         }
 478         return as;
 479 }
 480
 481 static void afs_destroy_sbi(struct afs_super_info *as)
 482 {
 483         if (as) {
 484                 afs_put_volume(as->cell, as->volume);
 485                 afs_put_cell(afs_net(as->net_ns), as->cell);
 486                 put_net(as->net_ns);
 487                 kfree(as);
 488         }
 489 }
 490
 491 static void afs_kill_super(struct super_block *sb)
 492 {
 493         struct afs_super_info *as = AFS_FS_S(sb);
 494         struct afs_net *net = afs_net(as->net_ns);
 495
 496         if (as->dyn_root)
 497                 afs_dynroot_depopulate(sb);
 498
 499         /* Clear the callback interests (which will do ilookup5) before
 500          * deactivating the superblock.
 501          */
 502         if (as->volume)
 503                 afs_clear_callback_interests(net, as->volume->servers);
 504         kill_anon_super(sb);
 505         if (as->volume)
 506                 afs_deactivate_volume(as->volume);
 507         afs_destroy_sbi(as);
 508 }
 509
 510 /*
 511  * Get an AFS superblock and root directory.
 512  */
 513 static int afs_get_tree(struct fs_context *fc)
 514 {
 515         struct afs_fs_context *ctx = fc->fs_private;
 516         struct super_block *sb;
 517         struct afs_super_info *as;
 518         int ret;
 519
 520         ret = afs_validate_fc(fc);
 521         if (ret)
 522                 goto error;
 523
 524         _enter("");
 525
 526         /* allocate a superblock info record */
 527         ret = -ENOMEM;
 528         as = afs_alloc_sbi(fc);
 529         if (!as)
 530                 goto error;
 531         fc->s_fs_info = as;
 532
 533         /* allocate a deviceless superblock */
 534         sb = sget_fc(fc,
 535                      as->dyn_root ? afs_dynroot_test_super : afs_test_super,
 536                      afs_set_super);
 537         if (IS_ERR(sb)) {
 538                 ret = PTR_ERR(sb);
 539                 goto error;
 540         }
 541
 542         if (!sb->s_root) {
 543                 /* initial superblock/root creation */
 544                 _debug("create");
 545                 ret = afs_fill_super(sb, ctx);
 546                 if (ret < 0)
 547                         goto error_sb;
 548                 sb->s_flags |= SB_ACTIVE;
 549         } else {
 550                 _debug("reuse");
 551                 ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
 552         }
 553
 554         fc->root = dget(sb->s_root);
 555         _leave(" = 0 [%p]", sb);
 556         return 0;
 557
 558 error_sb:
 559         deactivate_locked_super(sb);
 560 error:
 561         _leave(" = %d", ret);
 562         return ret;
 563 }
 564
 565 static void afs_free_fc(struct fs_context *fc)
 566 {
 567         struct afs_fs_context *ctx = fc->fs_private;
 568
 569         afs_destroy_sbi(fc->s_fs_info);
 570         afs_put_volume(ctx->cell, ctx->volume);
 571         afs_put_cell(ctx->net, ctx->cell);
 572         key_put(ctx->key);
 573         kfree(ctx);
 574 }
 575
 576 static const struct fs_context_operations afs_context_ops = {
 577         .free           = afs_free_fc,
 578         .parse_param    = afs_parse_param,
 579         .get_tree       = afs_get_tree,
 580 };
 581
 582 /*
 583  * Set up the filesystem mount context.
 584  */
 585 static int afs_init_fs_context(struct fs_context *fc)
 586 {
 587         struct afs_fs_context *ctx;
 588         struct afs_cell *cell;
 589
 590         ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
 591         if (!ctx)
 592                 return -ENOMEM;
 593
 594         ctx->type = AFSVL_ROVOL;
 595         ctx->net = afs_net(fc->net_ns);
 596
 597         /* Default to the workstation cell. */
 598         rcu_read_lock();
 599         cell = afs_lookup_cell_rcu(ctx->net, NULL, 0);
 600         rcu_read_unlock();
 601         if (IS_ERR(cell))
 602                 cell = NULL;
 603         ctx->cell = cell;
 604
 605         fc->fs_private = ctx;
 606         fc->ops = &afs_context_ops;
 607         return 0;
 608 }
 609
 610 /*
 611  * Initialise an inode cache slab element prior to any use.  Note that
 612  * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
 613  * inode to another.
 614  */
 615 static void afs_i_init_once(void *_vnode)
 616 {
 617         struct afs_vnode *vnode = _vnode;
 618
 619         memset(vnode, 0, sizeof(*vnode));
 620         inode_init_once(&vnode->vfs_inode);
 621         mutex_init(&vnode->io_lock);
 622         init_rwsem(&vnode->validate_lock);
 623         spin_lock_init(&vnode->wb_lock);
 624         spin_lock_init(&vnode->lock);
 625         INIT_LIST_HEAD(&vnode->wb_keys);
 626         INIT_LIST_HEAD(&vnode->pending_locks);
 627         INIT_LIST_HEAD(&vnode->granted_locks);
 628         INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 629         seqlock_init(&vnode->cb_lock);
 630 }
 631
 632 /*
 633  * allocate an AFS inode struct from our slab cache
 634  */
 635 static struct inode *afs_alloc_inode(struct super_block *sb)
 636 {
 637         struct afs_vnode *vnode;
 638
 639         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 640         if (!vnode)
 641                 return NULL;
 642
 643         atomic_inc(&afs_count_active_inodes);
 644
 645         /* Reset anything that shouldn't leak from one inode to the next. */
 646         memset(&vnode->fid, 0, sizeof(vnode->fid));
 647         memset(&vnode->status, 0, sizeof(vnode->status));
 648
 649         vnode->volume           = NULL;
 650         vnode->lock_key         = NULL;
 651         vnode->permit_cache     = NULL;
 652         vnode->cb_interest      = NULL;
 653 #ifdef CONFIG_AFS_FSCACHE
 654         vnode->cache            = NULL;
 655 #endif
 656
 657         vnode->flags            = 1 << AFS_VNODE_UNSET;
 658         vnode->cb_type          = 0;
 659         vnode->lock_state       = AFS_VNODE_LOCK_NONE;
 660
 661         _leave(" = %p", &vnode->vfs_inode);
 662         return &vnode->vfs_inode;
 663 }
 664
 665 static void afs_free_inode(struct inode *inode)
 666 {
 667         kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
 668 }
 669
 670 /*
 671  * destroy an AFS inode struct
 672  */
 673 static void afs_destroy_inode(struct inode *inode)
 674 {
 675         struct afs_vnode *vnode = AFS_FS_I(inode);
 676
 677         _enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
 678
 679         _debug("DESTROY INODE %p", inode);
 680
 681         ASSERTCMP(vnode->cb_interest, ==, NULL);
 682
 683         atomic_dec(&afs_count_active_inodes);
 684 }
 685
 686 /*
 687  * return information about an AFS volume
 688  */
 689 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 690 {
 691         struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
 692         struct afs_fs_cursor fc;
 693         struct afs_volume_status vs;
 694         struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 695         struct key *key;
 696         int ret;
 697
 698         buf->f_type     = dentry->d_sb->s_magic;
 699         buf->f_bsize    = AFS_BLOCK_SIZE;
 700         buf->f_namelen  = AFSNAMEMAX - 1;
 701
 702         if (as->dyn_root) {
 703                 buf->f_blocks   = 1;
 704                 buf->f_bavail   = 0;
 705                 buf->f_bfree    = 0;
 706                 return 0;
 707         }
 708
 709         key = afs_request_key(vnode->volume->cell);
 710         if (IS_ERR(key))
 711                 return PTR_ERR(key);
 712
 713         ret = -ERESTARTSYS;
 714         if (afs_begin_vnode_operation(&fc, vnode, key)) {
 715                 fc.flags |= AFS_FS_CURSOR_NO_VSLEEP;
 716                 while (afs_select_fileserver(&fc)) {
 717                         fc.cb_break = afs_calc_vnode_cb_break(vnode);
 718                         afs_fs_get_volume_status(&fc, &vs);
 719                 }
 720
 721                 afs_check_for_remote_deletion(&fc, fc.vnode);
 722                 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
 723                 ret = afs_end_vnode_operation(&fc);
 724         }
 725
 726         key_put(key);
 727
 728         if (ret == 0) {
 729                 if (vs.max_quota == 0)
 730                         buf->f_blocks = vs.part_max_blocks;
 731                 else
 732                         buf->f_blocks = vs.max_quota;
 733                 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 734         }
 735
 736         return ret;
 737 }