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@redhat.com> 14 * 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/init.h> 20 #include <linux/slab.h> 21 #include <linux/fs.h> 22 #include <linux/pagemap.h> 23 #include <linux/parser.h> 24 #include <linux/statfs.h> 25 #include "internal.h" 26 27 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */ 28 29 static void afs_i_init_once(void *foo, struct kmem_cache *cachep, 30 unsigned long flags); 31 static int afs_get_sb(struct file_system_type *fs_type, 32 int flags, const char *dev_name, 33 void *data, struct vfsmount *mnt); 34 static struct inode *afs_alloc_inode(struct super_block *sb); 35 static void afs_put_super(struct super_block *sb); 36 static void afs_destroy_inode(struct inode *inode); 37 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf); 38 39 struct file_system_type afs_fs_type = { 40 .owner = THIS_MODULE, 41 .name = "afs", 42 .get_sb = afs_get_sb, 43 .kill_sb = kill_anon_super, 44 .fs_flags = 0, 45 }; 46 47 static const struct super_operations afs_super_ops = { 48 .statfs = afs_statfs, 49 .alloc_inode = afs_alloc_inode, 50 .drop_inode = generic_delete_inode, 51 .write_inode = afs_write_inode, 52 .destroy_inode = afs_destroy_inode, 53 .clear_inode = afs_clear_inode, 54 .umount_begin = afs_umount_begin, 55 .put_super = afs_put_super, 56 }; 57 58 static struct kmem_cache *afs_inode_cachep; 59 static atomic_t afs_count_active_inodes; 60 61 enum { 62 afs_no_opt, 63 afs_opt_cell, 64 afs_opt_rwpath, 65 afs_opt_vol, 66 }; 67 68 static match_table_t afs_options_list = { 69 { afs_opt_cell, "cell=%s" }, 70 { afs_opt_rwpath, "rwpath" }, 71 { afs_opt_vol, "vol=%s" }, 72 { afs_no_opt, NULL }, 73 }; 74 75 /* 76 * initialise the filesystem 77 */ 78 int __init afs_fs_init(void) 79 { 80 int ret; 81 82 _enter(""); 83 84 /* create ourselves an inode cache */ 85 atomic_set(&afs_count_active_inodes, 0); 86 87 ret = -ENOMEM; 88 afs_inode_cachep = kmem_cache_create("afs_inode_cache", 89 sizeof(struct afs_vnode), 90 0, 91 SLAB_HWCACHE_ALIGN, 92 afs_i_init_once, 93 NULL); 94 if (!afs_inode_cachep) { 95 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n"); 96 return ret; 97 } 98 99 /* now export our filesystem to lesser mortals */ 100 ret = register_filesystem(&afs_fs_type); 101 if (ret < 0) { 102 kmem_cache_destroy(afs_inode_cachep); 103 _leave(" = %d", ret); 104 return ret; 105 } 106 107 _leave(" = 0"); 108 return 0; 109 } 110 111 /* 112 * clean up the filesystem 113 */ 114 void __exit afs_fs_exit(void) 115 { 116 _enter(""); 117 118 afs_mntpt_kill_timer(); 119 unregister_filesystem(&afs_fs_type); 120 121 if (atomic_read(&afs_count_active_inodes) != 0) { 122 printk("kAFS: %d active inode objects still present\n", 123 atomic_read(&afs_count_active_inodes)); 124 BUG(); 125 } 126 127 kmem_cache_destroy(afs_inode_cachep); 128 _leave(""); 129 } 130 131 /* 132 * parse the mount options 133 * - this function has been shamelessly adapted from the ext3 fs which 134 * shamelessly adapted it from the msdos fs 135 */ 136 static int afs_parse_options(struct afs_mount_params *params, 137 char *options, const char **devname) 138 { 139 struct afs_cell *cell; 140 substring_t args[MAX_OPT_ARGS]; 141 char *p; 142 int token; 143 144 _enter("%s", options); 145 146 options[PAGE_SIZE - 1] = 0; 147 148 while ((p = strsep(&options, ","))) { 149 if (!*p) 150 continue; 151 152 token = match_token(p, afs_options_list, args); 153 switch (token) { 154 case afs_opt_cell: 155 cell = afs_cell_lookup(args[0].from, 156 args[0].to - args[0].from); 157 if (IS_ERR(cell)) 158 return PTR_ERR(cell); 159 afs_put_cell(params->cell); 160 params->cell = cell; 161 break; 162 163 case afs_opt_rwpath: 164 params->rwpath = 1; 165 break; 166 167 case afs_opt_vol: 168 *devname = args[0].from; 169 break; 170 171 default: 172 printk(KERN_ERR "kAFS:" 173 " Unknown or invalid mount option: '%s'\n", p); 174 return -EINVAL; 175 } 176 } 177 178 _leave(" = 0"); 179 return 0; 180 } 181 182 /* 183 * parse a device name to get cell name, volume name, volume type and R/W 184 * selector 185 * - this can be one of the following: 186 * "%[cell:]volume[.]" R/W volume 187 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0), 188 * or R/W (rwpath=1) volume 189 * "%[cell:]volume.readonly" R/O volume 190 * "#[cell:]volume.readonly" R/O volume 191 * "%[cell:]volume.backup" Backup volume 192 * "#[cell:]volume.backup" Backup volume 193 */ 194 static int afs_parse_device_name(struct afs_mount_params *params, 195 const char *name) 196 { 197 struct afs_cell *cell; 198 const char *cellname, *suffix; 199 int cellnamesz; 200 201 _enter(",%s", name); 202 203 if (!name) { 204 printk(KERN_ERR "kAFS: no volume name specified\n"); 205 return -EINVAL; 206 } 207 208 if ((name[0] != '%' && name[0] != '#') || !name[1]) { 209 printk(KERN_ERR "kAFS: unparsable volume name\n"); 210 return -EINVAL; 211 } 212 213 /* determine the type of volume we're looking for */ 214 params->type = AFSVL_ROVOL; 215 params->force = false; 216 if (params->rwpath || name[0] == '%') { 217 params->type = AFSVL_RWVOL; 218 params->force = true; 219 } 220 name++; 221 222 /* split the cell name out if there is one */ 223 params->volname = strchr(name, ':'); 224 if (params->volname) { 225 cellname = name; 226 cellnamesz = params->volname - name; 227 params->volname++; 228 } else { 229 params->volname = name; 230 cellname = NULL; 231 cellnamesz = 0; 232 } 233 234 /* the volume type is further affected by a possible suffix */ 235 suffix = strrchr(params->volname, '.'); 236 if (suffix) { 237 if (strcmp(suffix, ".readonly") == 0) { 238 params->type = AFSVL_ROVOL; 239 params->force = true; 240 } else if (strcmp(suffix, ".backup") == 0) { 241 params->type = AFSVL_BACKVOL; 242 params->force = true; 243 } else if (suffix[1] == 0) { 244 } else { 245 suffix = NULL; 246 } 247 } 248 249 params->volnamesz = suffix ? 250 suffix - params->volname : strlen(params->volname); 251 252 _debug("cell %*.*s [%p]", 253 cellnamesz, cellnamesz, cellname ?: "", params->cell); 254 255 /* lookup the cell record */ 256 if (cellname || !params->cell) { 257 cell = afs_cell_lookup(cellname, cellnamesz); 258 if (IS_ERR(cell)) { 259 printk(KERN_ERR "kAFS: unable to lookup cell '%s'\n", 260 cellname ?: ""); 261 return PTR_ERR(cell); 262 } 263 afs_put_cell(params->cell); 264 params->cell = cell; 265 } 266 267 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s", 268 params->cell->name, params->cell, 269 params->volnamesz, params->volnamesz, params->volname, 270 suffix ?: "-", params->type, params->force ? " FORCE" : ""); 271 272 return 0; 273 } 274 275 /* 276 * check a superblock to see if it's the one we're looking for 277 */ 278 static int afs_test_super(struct super_block *sb, void *data) 279 { 280 struct afs_mount_params *params = data; 281 struct afs_super_info *as = sb->s_fs_info; 282 283 return as->volume == params->volume; 284 } 285 286 /* 287 * fill in the superblock 288 */ 289 static int afs_fill_super(struct super_block *sb, void *data) 290 { 291 struct afs_mount_params *params = data; 292 struct afs_super_info *as = NULL; 293 struct afs_fid fid; 294 struct dentry *root = NULL; 295 struct inode *inode = NULL; 296 int ret; 297 298 _enter(""); 299 300 /* allocate a superblock info record */ 301 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL); 302 if (!as) { 303 _leave(" = -ENOMEM"); 304 return -ENOMEM; 305 } 306 307 afs_get_volume(params->volume); 308 as->volume = params->volume; 309 310 /* fill in the superblock */ 311 sb->s_blocksize = PAGE_CACHE_SIZE; 312 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 313 sb->s_magic = AFS_FS_MAGIC; 314 sb->s_op = &afs_super_ops; 315 sb->s_fs_info = as; 316 317 /* allocate the root inode and dentry */ 318 fid.vid = as->volume->vid; 319 fid.vnode = 1; 320 fid.unique = 1; 321 inode = afs_iget(sb, params->key, &fid, NULL, NULL); 322 if (IS_ERR(inode)) 323 goto error_inode; 324 325 ret = -ENOMEM; 326 root = d_alloc_root(inode); 327 if (!root) 328 goto error; 329 330 sb->s_root = root; 331 332 _leave(" = 0"); 333 return 0; 334 335 error_inode: 336 ret = PTR_ERR(inode); 337 inode = NULL; 338 error: 339 iput(inode); 340 afs_put_volume(as->volume); 341 kfree(as); 342 343 sb->s_fs_info = NULL; 344 345 _leave(" = %d", ret); 346 return ret; 347 } 348 349 /* 350 * get an AFS superblock 351 */ 352 static int afs_get_sb(struct file_system_type *fs_type, 353 int flags, 354 const char *dev_name, 355 void *options, 356 struct vfsmount *mnt) 357 { 358 struct afs_mount_params params; 359 struct super_block *sb; 360 struct afs_volume *vol; 361 struct key *key; 362 int ret; 363 364 _enter(",,%s,%p", dev_name, options); 365 366 memset(¶ms, 0, sizeof(params)); 367 368 /* parse the options and device name */ 369 if (options) { 370 ret = afs_parse_options(¶ms, options, &dev_name); 371 if (ret < 0) 372 goto error; 373 } 374 375 ret = afs_parse_device_name(¶ms, dev_name); 376 if (ret < 0) 377 goto error; 378 379 /* try and do the mount securely */ 380 key = afs_request_key(params.cell); 381 if (IS_ERR(key)) { 382 _leave(" = %ld [key]", PTR_ERR(key)); 383 ret = PTR_ERR(key); 384 goto error; 385 } 386 params.key = key; 387 388 /* parse the device name */ 389 vol = afs_volume_lookup(¶ms); 390 if (IS_ERR(vol)) { 391 ret = PTR_ERR(vol); 392 goto error; 393 } 394 params.volume = vol; 395 396 /* allocate a deviceless superblock */ 397 sb = sget(fs_type, afs_test_super, set_anon_super, ¶ms); 398 if (IS_ERR(sb)) { 399 ret = PTR_ERR(sb); 400 goto error; 401 } 402 403 if (!sb->s_root) { 404 /* initial superblock/root creation */ 405 _debug("create"); 406 sb->s_flags = flags; 407 ret = afs_fill_super(sb, ¶ms); 408 if (ret < 0) { 409 up_write(&sb->s_umount); 410 deactivate_super(sb); 411 goto error; 412 } 413 sb->s_flags |= MS_ACTIVE; 414 } else { 415 _debug("reuse"); 416 ASSERTCMP(sb->s_flags, &, MS_ACTIVE); 417 } 418 419 simple_set_mnt(mnt, sb); 420 afs_put_volume(params.volume); 421 afs_put_cell(params.cell); 422 _leave(" = 0 [%p]", sb); 423 return 0; 424 425 error: 426 afs_put_volume(params.volume); 427 afs_put_cell(params.cell); 428 key_put(params.key); 429 _leave(" = %d", ret); 430 return ret; 431 } 432 433 /* 434 * finish the unmounting process on the superblock 435 */ 436 static void afs_put_super(struct super_block *sb) 437 { 438 struct afs_super_info *as = sb->s_fs_info; 439 440 _enter(""); 441 442 afs_put_volume(as->volume); 443 444 _leave(""); 445 } 446 447 /* 448 * initialise an inode cache slab element prior to any use 449 */ 450 static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep, 451 unsigned long flags) 452 { 453 struct afs_vnode *vnode = _vnode; 454 455 if (flags & SLAB_CTOR_CONSTRUCTOR) { 456 memset(vnode, 0, sizeof(*vnode)); 457 inode_init_once(&vnode->vfs_inode); 458 init_waitqueue_head(&vnode->update_waitq); 459 mutex_init(&vnode->permits_lock); 460 mutex_init(&vnode->validate_lock); 461 spin_lock_init(&vnode->writeback_lock); 462 spin_lock_init(&vnode->lock); 463 INIT_LIST_HEAD(&vnode->writebacks); 464 INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work); 465 } 466 } 467 468 /* 469 * allocate an AFS inode struct from our slab cache 470 */ 471 static struct inode *afs_alloc_inode(struct super_block *sb) 472 { 473 struct afs_vnode *vnode; 474 475 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL); 476 if (!vnode) 477 return NULL; 478 479 atomic_inc(&afs_count_active_inodes); 480 481 memset(&vnode->fid, 0, sizeof(vnode->fid)); 482 memset(&vnode->status, 0, sizeof(vnode->status)); 483 484 vnode->volume = NULL; 485 vnode->update_cnt = 0; 486 vnode->flags = 1 << AFS_VNODE_UNSET; 487 vnode->cb_promised = false; 488 489 _leave(" = %p", &vnode->vfs_inode); 490 return &vnode->vfs_inode; 491 } 492 493 /* 494 * destroy an AFS inode struct 495 */ 496 static void afs_destroy_inode(struct inode *inode) 497 { 498 struct afs_vnode *vnode = AFS_FS_I(inode); 499 500 _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode); 501 502 _debug("DESTROY INODE %p", inode); 503 504 ASSERTCMP(vnode->server, ==, NULL); 505 506 kmem_cache_free(afs_inode_cachep, vnode); 507 atomic_dec(&afs_count_active_inodes); 508 } 509 510 /* 511 * return information about an AFS volume 512 */ 513 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf) 514 { 515 struct afs_volume_status vs; 516 struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode); 517 struct key *key; 518 int ret; 519 520 key = afs_request_key(vnode->volume->cell); 521 if (IS_ERR(key)) 522 return PTR_ERR(key); 523 524 ret = afs_vnode_get_volume_status(vnode, key, &vs); 525 key_put(key); 526 if (ret < 0) { 527 _leave(" = %d", ret); 528 return ret; 529 } 530 531 buf->f_type = dentry->d_sb->s_magic; 532 buf->f_bsize = AFS_BLOCK_SIZE; 533 buf->f_namelen = AFSNAMEMAX - 1; 534 535 if (vs.max_quota == 0) 536 buf->f_blocks = vs.part_max_blocks; 537 else 538 buf->f_blocks = vs.max_quota; 539 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use; 540 return 0; 541 } 542