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 int afs_statfs(struct dentry *dentry, struct kstatfs *buf); 37 static int afs_show_devname(struct seq_file *m, struct dentry *root); 38 static int afs_show_options(struct seq_file *m, struct dentry *root); 39 static int afs_init_fs_context(struct fs_context *fc); 40 static const struct fs_parameter_description afs_fs_parameters; 41 42 struct file_system_type afs_fs_type = { 43 .owner = THIS_MODULE, 44 .name = "afs", 45 .init_fs_context = afs_init_fs_context, 46 .parameters = &afs_fs_parameters, 47 .kill_sb = afs_kill_super, 48 .fs_flags = 0, 49 }; 50 MODULE_ALIAS_FS("afs"); 51 52 int afs_net_id; 53 54 static const struct super_operations afs_super_ops = { 55 .statfs = afs_statfs, 56 .alloc_inode = afs_alloc_inode, 57 .drop_inode = afs_drop_inode, 58 .destroy_inode = afs_destroy_inode, 59 .evict_inode = afs_evict_inode, 60 .show_devname = afs_show_devname, 61 .show_options = afs_show_options, 62 }; 63 64 static struct kmem_cache *afs_inode_cachep; 65 static atomic_t afs_count_active_inodes; 66 67 enum afs_param { 68 Opt_autocell, 69 Opt_dyn, 70 Opt_source, 71 }; 72 73 static const struct fs_parameter_spec afs_param_specs[] = { 74 fsparam_flag ("autocell", Opt_autocell), 75 fsparam_flag ("dyn", Opt_dyn), 76 fsparam_string("source", Opt_source), 77 {} 78 }; 79 80 static const struct fs_parameter_description afs_fs_parameters = { 81 .name = "kAFS", 82 .specs = afs_param_specs, 83 }; 84 85 /* 86 * initialise the filesystem 87 */ 88 int __init afs_fs_init(void) 89 { 90 int ret; 91 92 _enter(""); 93 94 /* create ourselves an inode cache */ 95 atomic_set(&afs_count_active_inodes, 0); 96 97 ret = -ENOMEM; 98 afs_inode_cachep = kmem_cache_create("afs_inode_cache", 99 sizeof(struct afs_vnode), 100 0, 101 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, 102 afs_i_init_once); 103 if (!afs_inode_cachep) { 104 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n"); 105 return ret; 106 } 107 108 /* now export our filesystem to lesser mortals */ 109 ret = register_filesystem(&afs_fs_type); 110 if (ret < 0) { 111 kmem_cache_destroy(afs_inode_cachep); 112 _leave(" = %d", ret); 113 return ret; 114 } 115 116 _leave(" = 0"); 117 return 0; 118 } 119 120 /* 121 * clean up the filesystem 122 */ 123 void afs_fs_exit(void) 124 { 125 _enter(""); 126 127 afs_mntpt_kill_timer(); 128 unregister_filesystem(&afs_fs_type); 129 130 if (atomic_read(&afs_count_active_inodes) != 0) { 131 printk("kAFS: %d active inode objects still present\n", 132 atomic_read(&afs_count_active_inodes)); 133 BUG(); 134 } 135 136 /* 137 * Make sure all delayed rcu free inodes are flushed before we 138 * destroy cache. 139 */ 140 rcu_barrier(); 141 kmem_cache_destroy(afs_inode_cachep); 142 _leave(""); 143 } 144 145 /* 146 * Display the mount device name in /proc/mounts. 147 */ 148 static int afs_show_devname(struct seq_file *m, struct dentry *root) 149 { 150 struct afs_super_info *as = AFS_FS_S(root->d_sb); 151 struct afs_volume *volume = as->volume; 152 struct afs_cell *cell = as->cell; 153 const char *suf = ""; 154 char pref = '%'; 155 156 if (as->dyn_root) { 157 seq_puts(m, "none"); 158 return 0; 159 } 160 161 switch (volume->type) { 162 case AFSVL_RWVOL: 163 break; 164 case AFSVL_ROVOL: 165 pref = '#'; 166 if (volume->type_force) 167 suf = ".readonly"; 168 break; 169 case AFSVL_BACKVOL: 170 pref = '#'; 171 suf = ".backup"; 172 break; 173 } 174 175 seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf); 176 return 0; 177 } 178 179 /* 180 * Display the mount options in /proc/mounts. 181 */ 182 static int afs_show_options(struct seq_file *m, struct dentry *root) 183 { 184 struct afs_super_info *as = AFS_FS_S(root->d_sb); 185 186 if (as->dyn_root) 187 seq_puts(m, ",dyn"); 188 if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags)) 189 seq_puts(m, ",autocell"); 190 return 0; 191 } 192 193 /* 194 * Parse the source name to get cell name, volume name, volume type and R/W 195 * selector. 196 * 197 * This can be one of the following: 198 * "%[cell:]volume[.]" R/W volume 199 * "#[cell:]volume[.]" R/O or R/W volume (R/O parent), 200 * or R/W (R/W parent) volume 201 * "%[cell:]volume.readonly" R/O volume 202 * "#[cell:]volume.readonly" R/O volume 203 * "%[cell:]volume.backup" Backup volume 204 * "#[cell:]volume.backup" Backup volume 205 */ 206 static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param) 207 { 208 struct afs_fs_context *ctx = fc->fs_private; 209 struct afs_cell *cell; 210 const char *cellname, *suffix, *name = param->string; 211 int cellnamesz; 212 213 _enter(",%s", name); 214 215 if (!name) { 216 printk(KERN_ERR "kAFS: no volume name specified\n"); 217 return -EINVAL; 218 } 219 220 if ((name[0] != '%' && name[0] != '#') || !name[1]) { 221 /* To use dynroot, we don't want to have to provide a source */ 222 if (strcmp(name, "none") == 0) { 223 ctx->no_cell = true; 224 return 0; 225 } 226 printk(KERN_ERR "kAFS: unparsable volume name\n"); 227 return -EINVAL; 228 } 229 230 /* determine the type of volume we're looking for */ 231 if (name[0] == '%') { 232 ctx->type = AFSVL_RWVOL; 233 ctx->force = true; 234 } 235 name++; 236 237 /* split the cell name out if there is one */ 238 ctx->volname = strchr(name, ':'); 239 if (ctx->volname) { 240 cellname = name; 241 cellnamesz = ctx->volname - name; 242 ctx->volname++; 243 } else { 244 ctx->volname = name; 245 cellname = NULL; 246 cellnamesz = 0; 247 } 248 249 /* the volume type is further affected by a possible suffix */ 250 suffix = strrchr(ctx->volname, '.'); 251 if (suffix) { 252 if (strcmp(suffix, ".readonly") == 0) { 253 ctx->type = AFSVL_ROVOL; 254 ctx->force = true; 255 } else if (strcmp(suffix, ".backup") == 0) { 256 ctx->type = AFSVL_BACKVOL; 257 ctx->force = true; 258 } else if (suffix[1] == 0) { 259 } else { 260 suffix = NULL; 261 } 262 } 263 264 ctx->volnamesz = suffix ? 265 suffix - ctx->volname : strlen(ctx->volname); 266 267 _debug("cell %*.*s [%p]", 268 cellnamesz, cellnamesz, cellname ?: "", ctx->cell); 269 270 /* lookup the cell record */ 271 if (cellname) { 272 cell = afs_lookup_cell(ctx->net, cellname, cellnamesz, 273 NULL, false); 274 if (IS_ERR(cell)) { 275 pr_err("kAFS: unable to lookup cell '%*.*s'\n", 276 cellnamesz, cellnamesz, cellname ?: ""); 277 return PTR_ERR(cell); 278 } 279 afs_put_cell(ctx->net, ctx->cell); 280 ctx->cell = cell; 281 } 282 283 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s", 284 ctx->cell->name, ctx->cell, 285 ctx->volnamesz, ctx->volnamesz, ctx->volname, 286 suffix ?: "-", ctx->type, ctx->force ? " FORCE" : ""); 287 288 fc->source = param->string; 289 param->string = NULL; 290 return 0; 291 } 292 293 /* 294 * Parse a single mount parameter. 295 */ 296 static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param) 297 { 298 struct fs_parse_result result; 299 struct afs_fs_context *ctx = fc->fs_private; 300 int opt; 301 302 opt = fs_parse(fc, &afs_fs_parameters, param, &result); 303 if (opt < 0) 304 return opt; 305 306 switch (opt) { 307 case Opt_source: 308 return afs_parse_source(fc, param); 309 310 case Opt_autocell: 311 ctx->autocell = true; 312 break; 313 314 case Opt_dyn: 315 ctx->dyn_root = true; 316 break; 317 318 default: 319 return -EINVAL; 320 } 321 322 _leave(" = 0"); 323 return 0; 324 } 325 326 /* 327 * Validate the options, get the cell key and look up the volume. 328 */ 329 static int afs_validate_fc(struct fs_context *fc) 330 { 331 struct afs_fs_context *ctx = fc->fs_private; 332 struct afs_volume *volume; 333 struct key *key; 334 335 if (!ctx->dyn_root) { 336 if (ctx->no_cell) { 337 pr_warn("kAFS: Can only specify source 'none' with -o dyn\n"); 338 return -EINVAL; 339 } 340 341 if (!ctx->cell) { 342 pr_warn("kAFS: No cell specified\n"); 343 return -EDESTADDRREQ; 344 } 345 346 /* We try to do the mount securely. */ 347 key = afs_request_key(ctx->cell); 348 if (IS_ERR(key)) 349 return PTR_ERR(key); 350 351 ctx->key = key; 352 353 if (ctx->volume) { 354 afs_put_volume(ctx->cell, ctx->volume); 355 ctx->volume = NULL; 356 } 357 358 volume = afs_create_volume(ctx); 359 if (IS_ERR(volume)) 360 return PTR_ERR(volume); 361 362 ctx->volume = volume; 363 } 364 365 return 0; 366 } 367 368 /* 369 * check a superblock to see if it's the one we're looking for 370 */ 371 static int afs_test_super(struct super_block *sb, struct fs_context *fc) 372 { 373 struct afs_fs_context *ctx = fc->fs_private; 374 struct afs_super_info *as = AFS_FS_S(sb); 375 376 return (as->net_ns == fc->net_ns && 377 as->volume && 378 as->volume->vid == ctx->volume->vid && 379 !as->dyn_root); 380 } 381 382 static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc) 383 { 384 struct afs_super_info *as = AFS_FS_S(sb); 385 386 return (as->net_ns == fc->net_ns && 387 as->dyn_root); 388 } 389 390 static int afs_set_super(struct super_block *sb, struct fs_context *fc) 391 { 392 return set_anon_super(sb, NULL); 393 } 394 395 /* 396 * fill in the superblock 397 */ 398 static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx) 399 { 400 struct afs_super_info *as = AFS_FS_S(sb); 401 struct afs_fid fid; 402 struct inode *inode = NULL; 403 int ret; 404 405 _enter(""); 406 407 /* fill in the superblock */ 408 sb->s_blocksize = PAGE_SIZE; 409 sb->s_blocksize_bits = PAGE_SHIFT; 410 sb->s_magic = AFS_FS_MAGIC; 411 sb->s_op = &afs_super_ops; 412 if (!as->dyn_root) 413 sb->s_xattr = afs_xattr_handlers; 414 ret = super_setup_bdi(sb); 415 if (ret) 416 return ret; 417 sb->s_bdi->ra_pages = VM_READAHEAD_PAGES; 418 419 /* allocate the root inode and dentry */ 420 if (as->dyn_root) { 421 inode = afs_iget_pseudo_dir(sb, true); 422 sb->s_flags |= SB_RDONLY; 423 } else { 424 sprintf(sb->s_id, "%llu", as->volume->vid); 425 afs_activate_volume(as->volume); 426 fid.vid = as->volume->vid; 427 fid.vnode = 1; 428 fid.vnode_hi = 0; 429 fid.unique = 1; 430 inode = afs_iget(sb, ctx->key, &fid, NULL, NULL, NULL); 431 } 432 433 if (IS_ERR(inode)) 434 return PTR_ERR(inode); 435 436 if (ctx->autocell || as->dyn_root) 437 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags); 438 439 ret = -ENOMEM; 440 sb->s_root = d_make_root(inode); 441 if (!sb->s_root) 442 goto error; 443 444 if (as->dyn_root) { 445 sb->s_d_op = &afs_dynroot_dentry_operations; 446 ret = afs_dynroot_populate(sb); 447 if (ret < 0) 448 goto error; 449 } else { 450 sb->s_d_op = &afs_fs_dentry_operations; 451 } 452 453 _leave(" = 0"); 454 return 0; 455 456 error: 457 _leave(" = %d", ret); 458 return ret; 459 } 460 461 static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc) 462 { 463 struct afs_fs_context *ctx = fc->fs_private; 464 struct afs_super_info *as; 465 466 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL); 467 if (as) { 468 as->net_ns = get_net(fc->net_ns); 469 if (ctx->dyn_root) { 470 as->dyn_root = true; 471 } else { 472 as->cell = afs_get_cell(ctx->cell); 473 as->volume = __afs_get_volume(ctx->volume); 474 } 475 } 476 return as; 477 } 478 479 static void afs_destroy_sbi(struct afs_super_info *as) 480 { 481 if (as) { 482 afs_put_volume(as->cell, as->volume); 483 afs_put_cell(afs_net(as->net_ns), as->cell); 484 put_net(as->net_ns); 485 kfree(as); 486 } 487 } 488 489 static void afs_kill_super(struct super_block *sb) 490 { 491 struct afs_super_info *as = AFS_FS_S(sb); 492 struct afs_net *net = afs_net(as->net_ns); 493 494 if (as->dyn_root) 495 afs_dynroot_depopulate(sb); 496 497 /* Clear the callback interests (which will do ilookup5) before 498 * deactivating the superblock. 499 */ 500 if (as->volume) 501 afs_clear_callback_interests(net, as->volume->servers); 502 kill_anon_super(sb); 503 if (as->volume) 504 afs_deactivate_volume(as->volume); 505 afs_destroy_sbi(as); 506 } 507 508 /* 509 * Get an AFS superblock and root directory. 510 */ 511 static int afs_get_tree(struct fs_context *fc) 512 { 513 struct afs_fs_context *ctx = fc->fs_private; 514 struct super_block *sb; 515 struct afs_super_info *as; 516 int ret; 517 518 ret = afs_validate_fc(fc); 519 if (ret) 520 goto error; 521 522 _enter(""); 523 524 /* allocate a superblock info record */ 525 ret = -ENOMEM; 526 as = afs_alloc_sbi(fc); 527 if (!as) 528 goto error; 529 fc->s_fs_info = as; 530 531 /* allocate a deviceless superblock */ 532 sb = sget_fc(fc, 533 as->dyn_root ? afs_dynroot_test_super : afs_test_super, 534 afs_set_super); 535 if (IS_ERR(sb)) { 536 ret = PTR_ERR(sb); 537 goto error; 538 } 539 540 if (!sb->s_root) { 541 /* initial superblock/root creation */ 542 _debug("create"); 543 ret = afs_fill_super(sb, ctx); 544 if (ret < 0) 545 goto error_sb; 546 sb->s_flags |= SB_ACTIVE; 547 } else { 548 _debug("reuse"); 549 ASSERTCMP(sb->s_flags, &, SB_ACTIVE); 550 } 551 552 fc->root = dget(sb->s_root); 553 _leave(" = 0 [%p]", sb); 554 return 0; 555 556 error_sb: 557 deactivate_locked_super(sb); 558 error: 559 _leave(" = %d", ret); 560 return ret; 561 } 562 563 static void afs_free_fc(struct fs_context *fc) 564 { 565 struct afs_fs_context *ctx = fc->fs_private; 566 567 afs_destroy_sbi(fc->s_fs_info); 568 afs_put_volume(ctx->cell, ctx->volume); 569 afs_put_cell(ctx->net, ctx->cell); 570 key_put(ctx->key); 571 kfree(ctx); 572 } 573 574 static const struct fs_context_operations afs_context_ops = { 575 .free = afs_free_fc, 576 .parse_param = afs_parse_param, 577 .get_tree = afs_get_tree, 578 }; 579 580 /* 581 * Set up the filesystem mount context. 582 */ 583 static int afs_init_fs_context(struct fs_context *fc) 584 { 585 struct afs_fs_context *ctx; 586 struct afs_cell *cell; 587 588 ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL); 589 if (!ctx) 590 return -ENOMEM; 591 592 ctx->type = AFSVL_ROVOL; 593 ctx->net = afs_net(fc->net_ns); 594 595 /* Default to the workstation cell. */ 596 rcu_read_lock(); 597 cell = afs_lookup_cell_rcu(ctx->net, NULL, 0); 598 rcu_read_unlock(); 599 if (IS_ERR(cell)) 600 cell = NULL; 601 ctx->cell = cell; 602 603 fc->fs_private = ctx; 604 fc->ops = &afs_context_ops; 605 return 0; 606 } 607 608 /* 609 * Initialise an inode cache slab element prior to any use. Note that 610 * afs_alloc_inode() *must* reset anything that could incorrectly leak from one 611 * inode to another. 612 */ 613 static void afs_i_init_once(void *_vnode) 614 { 615 struct afs_vnode *vnode = _vnode; 616 617 memset(vnode, 0, sizeof(*vnode)); 618 inode_init_once(&vnode->vfs_inode); 619 mutex_init(&vnode->io_lock); 620 init_rwsem(&vnode->validate_lock); 621 spin_lock_init(&vnode->wb_lock); 622 spin_lock_init(&vnode->lock); 623 INIT_LIST_HEAD(&vnode->wb_keys); 624 INIT_LIST_HEAD(&vnode->pending_locks); 625 INIT_LIST_HEAD(&vnode->granted_locks); 626 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work); 627 seqlock_init(&vnode->cb_lock); 628 } 629 630 /* 631 * allocate an AFS inode struct from our slab cache 632 */ 633 static struct inode *afs_alloc_inode(struct super_block *sb) 634 { 635 struct afs_vnode *vnode; 636 637 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL); 638 if (!vnode) 639 return NULL; 640 641 atomic_inc(&afs_count_active_inodes); 642 643 /* Reset anything that shouldn't leak from one inode to the next. */ 644 memset(&vnode->fid, 0, sizeof(vnode->fid)); 645 memset(&vnode->status, 0, sizeof(vnode->status)); 646 647 vnode->volume = NULL; 648 vnode->lock_key = NULL; 649 vnode->permit_cache = NULL; 650 vnode->cb_interest = NULL; 651 #ifdef CONFIG_AFS_FSCACHE 652 vnode->cache = NULL; 653 #endif 654 655 vnode->flags = 1 << AFS_VNODE_UNSET; 656 vnode->cb_type = 0; 657 vnode->lock_state = AFS_VNODE_LOCK_NONE; 658 659 _leave(" = %p", &vnode->vfs_inode); 660 return &vnode->vfs_inode; 661 } 662 663 static void afs_i_callback(struct rcu_head *head) 664 { 665 struct inode *inode = container_of(head, struct inode, i_rcu); 666 struct afs_vnode *vnode = AFS_FS_I(inode); 667 kmem_cache_free(afs_inode_cachep, vnode); 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 call_rcu(&inode->i_rcu, afs_i_callback); 684 atomic_dec(&afs_count_active_inodes); 685 } 686 687 /* 688 * return information about an AFS volume 689 */ 690 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf) 691 { 692 struct afs_super_info *as = AFS_FS_S(dentry->d_sb); 693 struct afs_fs_cursor fc; 694 struct afs_volume_status vs; 695 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry)); 696 struct key *key; 697 int ret; 698 699 buf->f_type = dentry->d_sb->s_magic; 700 buf->f_bsize = AFS_BLOCK_SIZE; 701 buf->f_namelen = AFSNAMEMAX - 1; 702 703 if (as->dyn_root) { 704 buf->f_blocks = 1; 705 buf->f_bavail = 0; 706 buf->f_bfree = 0; 707 return 0; 708 } 709 710 key = afs_request_key(vnode->volume->cell); 711 if (IS_ERR(key)) 712 return PTR_ERR(key); 713 714 ret = -ERESTARTSYS; 715 if (afs_begin_vnode_operation(&fc, vnode, key)) { 716 fc.flags |= AFS_FS_CURSOR_NO_VSLEEP; 717 while (afs_select_fileserver(&fc)) { 718 fc.cb_break = afs_calc_vnode_cb_break(vnode); 719 afs_fs_get_volume_status(&fc, &vs); 720 } 721 722 afs_check_for_remote_deletion(&fc, fc.vnode); 723 afs_vnode_commit_status(&fc, vnode, fc.cb_break); 724 ret = afs_end_vnode_operation(&fc); 725 } 726 727 key_put(key); 728 729 if (ret == 0) { 730 if (vs.max_quota == 0) 731 buf->f_blocks = vs.part_max_blocks; 732 else 733 buf->f_blocks = vs.max_quota; 734 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use; 735 } 736 737 return ret; 738 } 739