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