1 /* AFS superblock handling 2 * 3 * Copyright (c) 2002, 2007 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/smp_lock.h> 23 #include <linux/fs.h> 24 #include <linux/pagemap.h> 25 #include <linux/parser.h> 26 #include <linux/statfs.h> 27 #include <linux/sched.h> 28 #include "internal.h" 29 30 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */ 31 32 static void afs_i_init_once(void *foo); 33 static int afs_get_sb(struct file_system_type *fs_type, 34 int flags, const char *dev_name, 35 void *data, struct vfsmount *mnt); 36 static struct inode *afs_alloc_inode(struct super_block *sb); 37 static void afs_put_super(struct super_block *sb); 38 static void afs_destroy_inode(struct inode *inode); 39 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf); 40 41 struct file_system_type afs_fs_type = { 42 .owner = THIS_MODULE, 43 .name = "afs", 44 .get_sb = afs_get_sb, 45 .kill_sb = kill_anon_super, 46 .fs_flags = 0, 47 }; 48 49 static const struct super_operations afs_super_ops = { 50 .statfs = afs_statfs, 51 .alloc_inode = afs_alloc_inode, 52 .drop_inode = afs_drop_inode, 53 .destroy_inode = afs_destroy_inode, 54 .evict_inode = afs_evict_inode, 55 .put_super = afs_put_super, 56 .show_options = generic_show_options, 57 }; 58 59 static struct kmem_cache *afs_inode_cachep; 60 static atomic_t afs_count_active_inodes; 61 62 enum { 63 afs_no_opt, 64 afs_opt_cell, 65 afs_opt_rwpath, 66 afs_opt_vol, 67 afs_opt_autocell, 68 }; 69 70 static const match_table_t afs_options_list = { 71 { afs_opt_cell, "cell=%s" }, 72 { afs_opt_rwpath, "rwpath" }, 73 { afs_opt_vol, "vol=%s" }, 74 { afs_opt_autocell, "autocell" }, 75 { afs_no_opt, NULL }, 76 }; 77 78 /* 79 * initialise the filesystem 80 */ 81 int __init afs_fs_init(void) 82 { 83 int ret; 84 85 _enter(""); 86 87 /* create ourselves an inode cache */ 88 atomic_set(&afs_count_active_inodes, 0); 89 90 ret = -ENOMEM; 91 afs_inode_cachep = kmem_cache_create("afs_inode_cache", 92 sizeof(struct afs_vnode), 93 0, 94 SLAB_HWCACHE_ALIGN, 95 afs_i_init_once); 96 if (!afs_inode_cachep) { 97 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n"); 98 return ret; 99 } 100 101 /* now export our filesystem to lesser mortals */ 102 ret = register_filesystem(&afs_fs_type); 103 if (ret < 0) { 104 kmem_cache_destroy(afs_inode_cachep); 105 _leave(" = %d", ret); 106 return ret; 107 } 108 109 _leave(" = 0"); 110 return 0; 111 } 112 113 /* 114 * clean up the filesystem 115 */ 116 void __exit afs_fs_exit(void) 117 { 118 _enter(""); 119 120 afs_mntpt_kill_timer(); 121 unregister_filesystem(&afs_fs_type); 122 123 if (atomic_read(&afs_count_active_inodes) != 0) { 124 printk("kAFS: %d active inode objects still present\n", 125 atomic_read(&afs_count_active_inodes)); 126 BUG(); 127 } 128 129 kmem_cache_destroy(afs_inode_cachep); 130 _leave(""); 131 } 132 133 /* 134 * parse the mount options 135 * - this function has been shamelessly adapted from the ext3 fs which 136 * shamelessly adapted it from the msdos fs 137 */ 138 static int afs_parse_options(struct afs_mount_params *params, 139 char *options, const char **devname) 140 { 141 struct afs_cell *cell; 142 substring_t args[MAX_OPT_ARGS]; 143 char *p; 144 int token; 145 146 _enter("%s", options); 147 148 options[PAGE_SIZE - 1] = 0; 149 150 while ((p = strsep(&options, ","))) { 151 if (!*p) 152 continue; 153 154 token = match_token(p, afs_options_list, args); 155 switch (token) { 156 case afs_opt_cell: 157 cell = afs_cell_lookup(args[0].from, 158 args[0].to - args[0].from, 159 false); 160 if (IS_ERR(cell)) 161 return PTR_ERR(cell); 162 afs_put_cell(params->cell); 163 params->cell = cell; 164 break; 165 166 case afs_opt_rwpath: 167 params->rwpath = 1; 168 break; 169 170 case afs_opt_vol: 171 *devname = args[0].from; 172 break; 173 174 case afs_opt_autocell: 175 params->autocell = 1; 176 break; 177 178 default: 179 printk(KERN_ERR "kAFS:" 180 " Unknown or invalid mount option: '%s'\n", p); 181 return -EINVAL; 182 } 183 } 184 185 _leave(" = 0"); 186 return 0; 187 } 188 189 /* 190 * parse a device name to get cell name, volume name, volume type and R/W 191 * selector 192 * - this can be one of the following: 193 * "%[cell:]volume[.]" R/W volume 194 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0), 195 * or R/W (rwpath=1) volume 196 * "%[cell:]volume.readonly" R/O volume 197 * "#[cell:]volume.readonly" R/O volume 198 * "%[cell:]volume.backup" Backup volume 199 * "#[cell:]volume.backup" Backup volume 200 */ 201 static int afs_parse_device_name(struct afs_mount_params *params, 202 const char *name) 203 { 204 struct afs_cell *cell; 205 const char *cellname, *suffix; 206 int cellnamesz; 207 208 _enter(",%s", name); 209 210 if (!name) { 211 printk(KERN_ERR "kAFS: no volume name specified\n"); 212 return -EINVAL; 213 } 214 215 if ((name[0] != '%' && name[0] != '#') || !name[1]) { 216 printk(KERN_ERR "kAFS: unparsable volume name\n"); 217 return -EINVAL; 218 } 219 220 /* determine the type of volume we're looking for */ 221 params->type = AFSVL_ROVOL; 222 params->force = false; 223 if (params->rwpath || name[0] == '%') { 224 params->type = AFSVL_RWVOL; 225 params->force = true; 226 } 227 name++; 228 229 /* split the cell name out if there is one */ 230 params->volname = strchr(name, ':'); 231 if (params->volname) { 232 cellname = name; 233 cellnamesz = params->volname - name; 234 params->volname++; 235 } else { 236 params->volname = name; 237 cellname = NULL; 238 cellnamesz = 0; 239 } 240 241 /* the volume type is further affected by a possible suffix */ 242 suffix = strrchr(params->volname, '.'); 243 if (suffix) { 244 if (strcmp(suffix, ".readonly") == 0) { 245 params->type = AFSVL_ROVOL; 246 params->force = true; 247 } else if (strcmp(suffix, ".backup") == 0) { 248 params->type = AFSVL_BACKVOL; 249 params->force = true; 250 } else if (suffix[1] == 0) { 251 } else { 252 suffix = NULL; 253 } 254 } 255 256 params->volnamesz = suffix ? 257 suffix - params->volname : strlen(params->volname); 258 259 _debug("cell %*.*s [%p]", 260 cellnamesz, cellnamesz, cellname ?: "", params->cell); 261 262 /* lookup the cell record */ 263 if (cellname || !params->cell) { 264 cell = afs_cell_lookup(cellname, cellnamesz, true); 265 if (IS_ERR(cell)) { 266 printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n", 267 cellnamesz, cellnamesz, cellname ?: ""); 268 return PTR_ERR(cell); 269 } 270 afs_put_cell(params->cell); 271 params->cell = cell; 272 } 273 274 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s", 275 params->cell->name, params->cell, 276 params->volnamesz, params->volnamesz, params->volname, 277 suffix ?: "-", params->type, params->force ? " FORCE" : ""); 278 279 return 0; 280 } 281 282 /* 283 * check a superblock to see if it's the one we're looking for 284 */ 285 static int afs_test_super(struct super_block *sb, void *data) 286 { 287 struct afs_mount_params *params = data; 288 struct afs_super_info *as = sb->s_fs_info; 289 290 return as->volume == params->volume; 291 } 292 293 /* 294 * fill in the superblock 295 */ 296 static int afs_fill_super(struct super_block *sb, void *data) 297 { 298 struct afs_mount_params *params = data; 299 struct afs_super_info *as = NULL; 300 struct afs_fid fid; 301 struct dentry *root = NULL; 302 struct inode *inode = NULL; 303 int ret; 304 305 _enter(""); 306 307 /* allocate a superblock info record */ 308 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL); 309 if (!as) { 310 _leave(" = -ENOMEM"); 311 return -ENOMEM; 312 } 313 314 afs_get_volume(params->volume); 315 as->volume = params->volume; 316 317 /* fill in the superblock */ 318 sb->s_blocksize = PAGE_CACHE_SIZE; 319 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 320 sb->s_magic = AFS_FS_MAGIC; 321 sb->s_op = &afs_super_ops; 322 sb->s_fs_info = as; 323 sb->s_bdi = &as->volume->bdi; 324 325 /* allocate the root inode and dentry */ 326 fid.vid = as->volume->vid; 327 fid.vnode = 1; 328 fid.unique = 1; 329 inode = afs_iget(sb, params->key, &fid, NULL, NULL); 330 if (IS_ERR(inode)) 331 goto error_inode; 332 333 if (params->autocell) 334 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags); 335 336 ret = -ENOMEM; 337 root = d_alloc_root(inode); 338 if (!root) 339 goto error; 340 341 sb->s_root = root; 342 343 _leave(" = 0"); 344 return 0; 345 346 error_inode: 347 ret = PTR_ERR(inode); 348 inode = NULL; 349 error: 350 iput(inode); 351 afs_put_volume(as->volume); 352 kfree(as); 353 354 sb->s_fs_info = NULL; 355 356 _leave(" = %d", ret); 357 return ret; 358 } 359 360 /* 361 * get an AFS superblock 362 */ 363 static int afs_get_sb(struct file_system_type *fs_type, 364 int flags, 365 const char *dev_name, 366 void *options, 367 struct vfsmount *mnt) 368 { 369 struct afs_mount_params params; 370 struct super_block *sb; 371 struct afs_volume *vol; 372 struct key *key; 373 char *new_opts = kstrdup(options, GFP_KERNEL); 374 int ret; 375 376 _enter(",,%s,%p", dev_name, options); 377 378 memset(¶ms, 0, sizeof(params)); 379 380 /* parse the options and device name */ 381 if (options) { 382 ret = afs_parse_options(¶ms, options, &dev_name); 383 if (ret < 0) 384 goto error; 385 } 386 387 ret = afs_parse_device_name(¶ms, dev_name); 388 if (ret < 0) 389 goto error; 390 391 /* try and do the mount securely */ 392 key = afs_request_key(params.cell); 393 if (IS_ERR(key)) { 394 _leave(" = %ld [key]", PTR_ERR(key)); 395 ret = PTR_ERR(key); 396 goto error; 397 } 398 params.key = key; 399 400 /* parse the device name */ 401 vol = afs_volume_lookup(¶ms); 402 if (IS_ERR(vol)) { 403 ret = PTR_ERR(vol); 404 goto error; 405 } 406 params.volume = vol; 407 408 /* allocate a deviceless superblock */ 409 sb = sget(fs_type, afs_test_super, set_anon_super, ¶ms); 410 if (IS_ERR(sb)) { 411 ret = PTR_ERR(sb); 412 goto error; 413 } 414 415 if (!sb->s_root) { 416 /* initial superblock/root creation */ 417 _debug("create"); 418 sb->s_flags = flags; 419 ret = afs_fill_super(sb, ¶ms); 420 if (ret < 0) { 421 deactivate_locked_super(sb); 422 goto error; 423 } 424 save_mount_options(sb, new_opts); 425 sb->s_flags |= MS_ACTIVE; 426 } else { 427 _debug("reuse"); 428 ASSERTCMP(sb->s_flags, &, MS_ACTIVE); 429 } 430 431 simple_set_mnt(mnt, sb); 432 afs_put_volume(params.volume); 433 afs_put_cell(params.cell); 434 kfree(new_opts); 435 _leave(" = 0 [%p]", sb); 436 return 0; 437 438 error: 439 afs_put_volume(params.volume); 440 afs_put_cell(params.cell); 441 key_put(params.key); 442 kfree(new_opts); 443 _leave(" = %d", ret); 444 return ret; 445 } 446 447 /* 448 * finish the unmounting process on the superblock 449 */ 450 static void afs_put_super(struct super_block *sb) 451 { 452 struct afs_super_info *as = sb->s_fs_info; 453 454 _enter(""); 455 456 lock_kernel(); 457 458 afs_put_volume(as->volume); 459 460 unlock_kernel(); 461 462 _leave(""); 463 } 464 465 /* 466 * initialise an inode cache slab element prior to any use 467 */ 468 static void afs_i_init_once(void *_vnode) 469 { 470 struct afs_vnode *vnode = _vnode; 471 472 memset(vnode, 0, sizeof(*vnode)); 473 inode_init_once(&vnode->vfs_inode); 474 init_waitqueue_head(&vnode->update_waitq); 475 mutex_init(&vnode->permits_lock); 476 mutex_init(&vnode->validate_lock); 477 spin_lock_init(&vnode->writeback_lock); 478 spin_lock_init(&vnode->lock); 479 INIT_LIST_HEAD(&vnode->writebacks); 480 INIT_LIST_HEAD(&vnode->pending_locks); 481 INIT_LIST_HEAD(&vnode->granted_locks); 482 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work); 483 INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work); 484 } 485 486 /* 487 * allocate an AFS inode struct from our slab cache 488 */ 489 static struct inode *afs_alloc_inode(struct super_block *sb) 490 { 491 struct afs_vnode *vnode; 492 493 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL); 494 if (!vnode) 495 return NULL; 496 497 atomic_inc(&afs_count_active_inodes); 498 499 memset(&vnode->fid, 0, sizeof(vnode->fid)); 500 memset(&vnode->status, 0, sizeof(vnode->status)); 501 502 vnode->volume = NULL; 503 vnode->update_cnt = 0; 504 vnode->flags = 1 << AFS_VNODE_UNSET; 505 vnode->cb_promised = false; 506 507 _leave(" = %p", &vnode->vfs_inode); 508 return &vnode->vfs_inode; 509 } 510 511 /* 512 * destroy an AFS inode struct 513 */ 514 static void afs_destroy_inode(struct inode *inode) 515 { 516 struct afs_vnode *vnode = AFS_FS_I(inode); 517 518 _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode); 519 520 _debug("DESTROY INODE %p", inode); 521 522 ASSERTCMP(vnode->server, ==, NULL); 523 524 kmem_cache_free(afs_inode_cachep, vnode); 525 atomic_dec(&afs_count_active_inodes); 526 } 527 528 /* 529 * return information about an AFS volume 530 */ 531 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf) 532 { 533 struct afs_volume_status vs; 534 struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode); 535 struct key *key; 536 int ret; 537 538 key = afs_request_key(vnode->volume->cell); 539 if (IS_ERR(key)) 540 return PTR_ERR(key); 541 542 ret = afs_vnode_get_volume_status(vnode, key, &vs); 543 key_put(key); 544 if (ret < 0) { 545 _leave(" = %d", ret); 546 return ret; 547 } 548 549 buf->f_type = dentry->d_sb->s_magic; 550 buf->f_bsize = AFS_BLOCK_SIZE; 551 buf->f_namelen = AFSNAMEMAX - 1; 552 553 if (vs.max_quota == 0) 554 buf->f_blocks = vs.part_max_blocks; 555 else 556 buf->f_blocks = vs.max_quota; 557 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use; 558 return 0; 559 } 560