1 /* 2 * Copyright (c) 2002 Red Hat, Inc. All rights reserved. 3 * 4 * This software may be freely redistributed under the terms of the 5 * GNU General Public License. 6 * 7 * You should have received a copy of the GNU General Public License 8 * along with this program; if not, write to the Free Software 9 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 10 * 11 * Authors: David Woodhouse <dwmw2@infradead.org> 12 * David Howells <dhowells@redhat.com> 13 * 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/init.h> 19 #include <linux/fs.h> 20 #include <linux/pagemap.h> 21 #include <linux/sched.h> 22 #include <linux/mount.h> 23 #include <linux/namei.h> 24 #include <linux/iversion.h> 25 #include "internal.h" 26 27 static const struct inode_operations afs_symlink_inode_operations = { 28 .get_link = page_get_link, 29 .listxattr = afs_listxattr, 30 }; 31 32 /* 33 * Initialise an inode from the vnode status. 34 */ 35 static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key) 36 { 37 struct inode *inode = AFS_VNODE_TO_I(vnode); 38 39 _debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu", 40 vnode->status.type, 41 vnode->status.nlink, 42 (unsigned long long) vnode->status.size, 43 vnode->status.data_version, 44 vnode->status.mode); 45 46 read_seqlock_excl(&vnode->cb_lock); 47 48 afs_update_inode_from_status(vnode, &vnode->status, NULL, 49 AFS_VNODE_NOT_YET_SET); 50 51 switch (vnode->status.type) { 52 case AFS_FTYPE_FILE: 53 inode->i_mode = S_IFREG | vnode->status.mode; 54 inode->i_op = &afs_file_inode_operations; 55 inode->i_fop = &afs_file_operations; 56 inode->i_mapping->a_ops = &afs_fs_aops; 57 break; 58 case AFS_FTYPE_DIR: 59 inode->i_mode = S_IFDIR | vnode->status.mode; 60 inode->i_op = &afs_dir_inode_operations; 61 inode->i_fop = &afs_dir_file_operations; 62 inode->i_mapping->a_ops = &afs_dir_aops; 63 break; 64 case AFS_FTYPE_SYMLINK: 65 /* Symlinks with a mode of 0644 are actually mountpoints. */ 66 if ((vnode->status.mode & 0777) == 0644) { 67 inode->i_flags |= S_AUTOMOUNT; 68 69 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags); 70 71 inode->i_mode = S_IFDIR | 0555; 72 inode->i_op = &afs_mntpt_inode_operations; 73 inode->i_fop = &afs_mntpt_file_operations; 74 inode->i_mapping->a_ops = &afs_fs_aops; 75 } else { 76 inode->i_mode = S_IFLNK | vnode->status.mode; 77 inode->i_op = &afs_symlink_inode_operations; 78 inode->i_mapping->a_ops = &afs_fs_aops; 79 } 80 inode_nohighmem(inode); 81 break; 82 default: 83 printk("kAFS: AFS vnode with undefined type\n"); 84 read_sequnlock_excl(&vnode->cb_lock); 85 return afs_protocol_error(NULL, -EBADMSG); 86 } 87 88 inode->i_blocks = 0; 89 vnode->invalid_before = vnode->status.data_version; 90 91 read_sequnlock_excl(&vnode->cb_lock); 92 return 0; 93 } 94 95 /* 96 * Fetch file status from the volume. 97 */ 98 int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool new_inode) 99 { 100 struct afs_fs_cursor fc; 101 int ret; 102 103 _enter("%s,{%x:%u.%u,S=%lx}", 104 vnode->volume->name, 105 vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique, 106 vnode->flags); 107 108 ret = -ERESTARTSYS; 109 if (afs_begin_vnode_operation(&fc, vnode, key)) { 110 while (afs_select_fileserver(&fc)) { 111 fc.cb_break = vnode->cb_break + vnode->cb_s_break; 112 afs_fs_fetch_file_status(&fc, NULL, new_inode); 113 } 114 115 afs_check_for_remote_deletion(&fc, fc.vnode); 116 afs_vnode_commit_status(&fc, vnode, fc.cb_break); 117 ret = afs_end_vnode_operation(&fc); 118 } 119 120 _leave(" = %d", ret); 121 return ret; 122 } 123 124 /* 125 * iget5() comparator 126 */ 127 int afs_iget5_test(struct inode *inode, void *opaque) 128 { 129 struct afs_iget_data *data = opaque; 130 131 return inode->i_ino == data->fid.vnode && 132 inode->i_generation == data->fid.unique; 133 } 134 135 /* 136 * iget5() comparator for inode created by autocell operations 137 * 138 * These pseudo inodes don't match anything. 139 */ 140 static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque) 141 { 142 return 0; 143 } 144 145 /* 146 * iget5() inode initialiser 147 */ 148 static int afs_iget5_set(struct inode *inode, void *opaque) 149 { 150 struct afs_iget_data *data = opaque; 151 struct afs_vnode *vnode = AFS_FS_I(inode); 152 153 inode->i_ino = data->fid.vnode; 154 inode->i_generation = data->fid.unique; 155 vnode->fid = data->fid; 156 vnode->volume = data->volume; 157 158 return 0; 159 } 160 161 /* 162 * Create an inode for a dynamic root directory or an autocell dynamic 163 * automount dir. 164 */ 165 struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root) 166 { 167 struct afs_iget_data data; 168 struct afs_super_info *as; 169 struct afs_vnode *vnode; 170 struct inode *inode; 171 static atomic_t afs_autocell_ino; 172 173 _enter(""); 174 175 as = sb->s_fs_info; 176 if (as->volume) { 177 data.volume = as->volume; 178 data.fid.vid = as->volume->vid; 179 } 180 if (root) { 181 data.fid.vnode = 1; 182 data.fid.unique = 1; 183 } else { 184 data.fid.vnode = atomic_inc_return(&afs_autocell_ino); 185 data.fid.unique = 0; 186 } 187 188 inode = iget5_locked(sb, data.fid.vnode, 189 afs_iget5_pseudo_dir_test, afs_iget5_set, 190 &data); 191 if (!inode) { 192 _leave(" = -ENOMEM"); 193 return ERR_PTR(-ENOMEM); 194 } 195 196 _debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }", 197 inode, inode->i_ino, data.fid.vid, data.fid.vnode, 198 data.fid.unique); 199 200 vnode = AFS_FS_I(inode); 201 202 /* there shouldn't be an existing inode */ 203 BUG_ON(!(inode->i_state & I_NEW)); 204 205 inode->i_size = 0; 206 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; 207 if (root) { 208 inode->i_op = &afs_dynroot_inode_operations; 209 inode->i_fop = &afs_dynroot_file_operations; 210 } else { 211 inode->i_op = &afs_autocell_inode_operations; 212 } 213 set_nlink(inode, 2); 214 inode->i_uid = GLOBAL_ROOT_UID; 215 inode->i_gid = GLOBAL_ROOT_GID; 216 inode->i_ctime.tv_sec = get_seconds(); 217 inode->i_ctime.tv_nsec = 0; 218 inode->i_atime = inode->i_mtime = inode->i_ctime; 219 inode->i_blocks = 0; 220 inode_set_iversion_raw(inode, 0); 221 inode->i_generation = 0; 222 223 set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags); 224 if (!root) { 225 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags); 226 inode->i_flags |= S_AUTOMOUNT; 227 } 228 229 inode->i_flags |= S_NOATIME; 230 unlock_new_inode(inode); 231 _leave(" = %p", inode); 232 return inode; 233 } 234 235 /* 236 * Get a cache cookie for an inode. 237 */ 238 static void afs_get_inode_cache(struct afs_vnode *vnode) 239 { 240 #ifdef CONFIG_AFS_FSCACHE 241 struct { 242 u32 vnode_id; 243 u32 unique; 244 u32 vnode_id_ext[2]; /* Allow for a 96-bit key */ 245 } __packed key; 246 struct afs_vnode_cache_aux aux; 247 248 if (vnode->status.type == AFS_FTYPE_DIR) { 249 vnode->cache = NULL; 250 return; 251 } 252 253 key.vnode_id = vnode->fid.vnode; 254 key.unique = vnode->fid.unique; 255 key.vnode_id_ext[0] = 0; 256 key.vnode_id_ext[1] = 0; 257 aux.data_version = vnode->status.data_version; 258 259 vnode->cache = fscache_acquire_cookie(vnode->volume->cache, 260 &afs_vnode_cache_index_def, 261 &key, sizeof(key), 262 &aux, sizeof(aux), 263 vnode, vnode->status.size, true); 264 #endif 265 } 266 267 /* 268 * inode retrieval 269 */ 270 struct inode *afs_iget(struct super_block *sb, struct key *key, 271 struct afs_fid *fid, struct afs_file_status *status, 272 struct afs_callback *cb, struct afs_cb_interest *cbi) 273 { 274 struct afs_iget_data data = { .fid = *fid }; 275 struct afs_super_info *as; 276 struct afs_vnode *vnode; 277 struct inode *inode; 278 int ret; 279 280 _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique); 281 282 as = sb->s_fs_info; 283 data.volume = as->volume; 284 285 inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set, 286 &data); 287 if (!inode) { 288 _leave(" = -ENOMEM"); 289 return ERR_PTR(-ENOMEM); 290 } 291 292 _debug("GOT INODE %p { vl=%x vn=%x, u=%x }", 293 inode, fid->vid, fid->vnode, fid->unique); 294 295 vnode = AFS_FS_I(inode); 296 297 /* deal with an existing inode */ 298 if (!(inode->i_state & I_NEW)) { 299 _leave(" = %p", inode); 300 return inode; 301 } 302 303 if (!status) { 304 /* it's a remotely extant inode */ 305 ret = afs_fetch_status(vnode, key, true); 306 if (ret < 0) 307 goto bad_inode; 308 } else { 309 /* it's an inode we just created */ 310 memcpy(&vnode->status, status, sizeof(vnode->status)); 311 312 if (!cb) { 313 /* it's a symlink we just created (the fileserver 314 * didn't give us a callback) */ 315 vnode->cb_version = 0; 316 vnode->cb_type = 0; 317 vnode->cb_expires_at = 0; 318 } else { 319 vnode->cb_version = cb->version; 320 vnode->cb_type = cb->type; 321 vnode->cb_expires_at = cb->expiry; 322 vnode->cb_interest = afs_get_cb_interest(cbi); 323 set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags); 324 } 325 326 vnode->cb_expires_at += ktime_get_real_seconds(); 327 } 328 329 ret = afs_inode_init_from_status(vnode, key); 330 if (ret < 0) 331 goto bad_inode; 332 333 afs_get_inode_cache(vnode); 334 335 /* success */ 336 clear_bit(AFS_VNODE_UNSET, &vnode->flags); 337 inode->i_flags |= S_NOATIME; 338 unlock_new_inode(inode); 339 _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type); 340 return inode; 341 342 /* failure */ 343 bad_inode: 344 iget_failed(inode); 345 _leave(" = %d [bad]", ret); 346 return ERR_PTR(ret); 347 } 348 349 /* 350 * mark the data attached to an inode as obsolete due to a write on the server 351 * - might also want to ditch all the outstanding writes and dirty pages 352 */ 353 void afs_zap_data(struct afs_vnode *vnode) 354 { 355 _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); 356 357 #ifdef CONFIG_AFS_FSCACHE 358 fscache_invalidate(vnode->cache); 359 #endif 360 361 /* nuke all the non-dirty pages that aren't locked, mapped or being 362 * written back in a regular file and completely discard the pages in a 363 * directory or symlink */ 364 if (S_ISREG(vnode->vfs_inode.i_mode)) 365 invalidate_remote_inode(&vnode->vfs_inode); 366 else 367 invalidate_inode_pages2(vnode->vfs_inode.i_mapping); 368 } 369 370 /* 371 * validate a vnode/inode 372 * - there are several things we need to check 373 * - parent dir data changes (rm, rmdir, rename, mkdir, create, link, 374 * symlink) 375 * - parent dir metadata changed (security changes) 376 * - dentry data changed (write, truncate) 377 * - dentry metadata changed (security changes) 378 */ 379 int afs_validate(struct afs_vnode *vnode, struct key *key) 380 { 381 time64_t now = ktime_get_real_seconds(); 382 bool valid = false; 383 int ret; 384 385 _enter("{v={%x:%u} fl=%lx},%x", 386 vnode->fid.vid, vnode->fid.vnode, vnode->flags, 387 key_serial(key)); 388 389 /* Quickly check the callback state. Ideally, we'd use read_seqbegin 390 * here, but we have no way to pass the net namespace to the RCU 391 * cleanup for the server record. 392 */ 393 read_seqlock_excl(&vnode->cb_lock); 394 395 if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) { 396 if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break) { 397 vnode->cb_s_break = vnode->cb_interest->server->cb_s_break; 398 } else if (vnode->status.type == AFS_FTYPE_DIR && 399 test_bit(AFS_VNODE_DIR_VALID, &vnode->flags) && 400 vnode->cb_expires_at - 10 > now) { 401 valid = true; 402 } else if (!test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) && 403 vnode->cb_expires_at - 10 > now) { 404 valid = true; 405 } 406 } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) { 407 valid = true; 408 } 409 410 read_sequnlock_excl(&vnode->cb_lock); 411 412 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) 413 clear_nlink(&vnode->vfs_inode); 414 415 if (valid) 416 goto valid; 417 418 mutex_lock(&vnode->validate_lock); 419 420 /* if the promise has expired, we need to check the server again to get 421 * a new promise - note that if the (parent) directory's metadata was 422 * changed then the security may be different and we may no longer have 423 * access */ 424 if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) { 425 _debug("not promised"); 426 ret = afs_fetch_status(vnode, key, false); 427 if (ret < 0) { 428 if (ret == -ENOENT) { 429 set_bit(AFS_VNODE_DELETED, &vnode->flags); 430 ret = -ESTALE; 431 } 432 goto error_unlock; 433 } 434 _debug("new promise [fl=%lx]", vnode->flags); 435 } 436 437 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) { 438 _debug("file already deleted"); 439 ret = -ESTALE; 440 goto error_unlock; 441 } 442 443 /* if the vnode's data version number changed then its contents are 444 * different */ 445 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) 446 afs_zap_data(vnode); 447 mutex_unlock(&vnode->validate_lock); 448 valid: 449 _leave(" = 0"); 450 return 0; 451 452 error_unlock: 453 mutex_unlock(&vnode->validate_lock); 454 _leave(" = %d", ret); 455 return ret; 456 } 457 458 /* 459 * read the attributes of an inode 460 */ 461 int afs_getattr(const struct path *path, struct kstat *stat, 462 u32 request_mask, unsigned int query_flags) 463 { 464 struct inode *inode = d_inode(path->dentry); 465 struct afs_vnode *vnode = AFS_FS_I(inode); 466 int seq = 0; 467 468 _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation); 469 470 do { 471 read_seqbegin_or_lock(&vnode->cb_lock, &seq); 472 generic_fillattr(inode, stat); 473 } while (need_seqretry(&vnode->cb_lock, seq)); 474 475 done_seqretry(&vnode->cb_lock, seq); 476 return 0; 477 } 478 479 /* 480 * discard an AFS inode 481 */ 482 int afs_drop_inode(struct inode *inode) 483 { 484 _enter(""); 485 486 if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags)) 487 return generic_delete_inode(inode); 488 else 489 return generic_drop_inode(inode); 490 } 491 492 /* 493 * clear an AFS inode 494 */ 495 void afs_evict_inode(struct inode *inode) 496 { 497 struct afs_vnode *vnode; 498 499 vnode = AFS_FS_I(inode); 500 501 _enter("{%x:%u.%d}", 502 vnode->fid.vid, 503 vnode->fid.vnode, 504 vnode->fid.unique); 505 506 _debug("CLEAR INODE %p", inode); 507 508 ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode); 509 510 truncate_inode_pages_final(&inode->i_data); 511 clear_inode(inode); 512 513 if (vnode->cb_interest) { 514 afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest); 515 vnode->cb_interest = NULL; 516 } 517 518 while (!list_empty(&vnode->wb_keys)) { 519 struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next, 520 struct afs_wb_key, vnode_link); 521 list_del(&wbk->vnode_link); 522 afs_put_wb_key(wbk); 523 } 524 525 #ifdef CONFIG_AFS_FSCACHE 526 { 527 struct afs_vnode_cache_aux aux; 528 529 aux.data_version = vnode->status.data_version; 530 fscache_relinquish_cookie(vnode->cache, &aux, 531 test_bit(AFS_VNODE_DELETED, &vnode->flags)); 532 vnode->cache = NULL; 533 } 534 #endif 535 536 afs_put_permits(rcu_access_pointer(vnode->permit_cache)); 537 _leave(""); 538 } 539 540 /* 541 * set the attributes of an inode 542 */ 543 int afs_setattr(struct dentry *dentry, struct iattr *attr) 544 { 545 struct afs_fs_cursor fc; 546 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry)); 547 struct key *key; 548 int ret; 549 550 _enter("{%x:%u},{n=%pd},%x", 551 vnode->fid.vid, vnode->fid.vnode, dentry, 552 attr->ia_valid); 553 554 if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID | 555 ATTR_MTIME))) { 556 _leave(" = 0 [unsupported]"); 557 return 0; 558 } 559 560 /* flush any dirty data outstanding on a regular file */ 561 if (S_ISREG(vnode->vfs_inode.i_mode)) 562 filemap_write_and_wait(vnode->vfs_inode.i_mapping); 563 564 if (attr->ia_valid & ATTR_FILE) { 565 key = afs_file_key(attr->ia_file); 566 } else { 567 key = afs_request_key(vnode->volume->cell); 568 if (IS_ERR(key)) { 569 ret = PTR_ERR(key); 570 goto error; 571 } 572 } 573 574 ret = -ERESTARTSYS; 575 if (afs_begin_vnode_operation(&fc, vnode, key)) { 576 while (afs_select_fileserver(&fc)) { 577 fc.cb_break = vnode->cb_break + vnode->cb_s_break; 578 afs_fs_setattr(&fc, attr); 579 } 580 581 afs_check_for_remote_deletion(&fc, fc.vnode); 582 afs_vnode_commit_status(&fc, vnode, fc.cb_break); 583 ret = afs_end_vnode_operation(&fc); 584 } 585 586 if (!(attr->ia_valid & ATTR_FILE)) 587 key_put(key); 588 589 error: 590 _leave(" = %d", ret); 591 return ret; 592 } 593