1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/file.h> 13 #include <linux/sched.h> 14 #include <linux/namei.h> 15 #include <linux/slab.h> 16 #include <linux/xattr.h> 17 #include <linux/posix_acl.h> 18 19 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx) 20 { 21 struct fuse_conn *fc = get_fuse_conn(dir); 22 struct fuse_inode *fi = get_fuse_inode(dir); 23 24 if (!fc->do_readdirplus) 25 return false; 26 if (!fc->readdirplus_auto) 27 return true; 28 if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state)) 29 return true; 30 if (ctx->pos == 0) 31 return true; 32 return false; 33 } 34 35 static void fuse_advise_use_readdirplus(struct inode *dir) 36 { 37 struct fuse_inode *fi = get_fuse_inode(dir); 38 39 set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state); 40 } 41 42 union fuse_dentry { 43 u64 time; 44 struct rcu_head rcu; 45 }; 46 47 static inline void fuse_dentry_settime(struct dentry *entry, u64 time) 48 { 49 ((union fuse_dentry *) entry->d_fsdata)->time = time; 50 } 51 52 static inline u64 fuse_dentry_time(struct dentry *entry) 53 { 54 return ((union fuse_dentry *) entry->d_fsdata)->time; 55 } 56 57 /* 58 * FUSE caches dentries and attributes with separate timeout. The 59 * time in jiffies until the dentry/attributes are valid is stored in 60 * dentry->d_fsdata and fuse_inode->i_time respectively. 61 */ 62 63 /* 64 * Calculate the time in jiffies until a dentry/attributes are valid 65 */ 66 static u64 time_to_jiffies(u64 sec, u32 nsec) 67 { 68 if (sec || nsec) { 69 struct timespec64 ts = { 70 sec, 71 min_t(u32, nsec, NSEC_PER_SEC - 1) 72 }; 73 74 return get_jiffies_64() + timespec64_to_jiffies(&ts); 75 } else 76 return 0; 77 } 78 79 /* 80 * Set dentry and possibly attribute timeouts from the lookup/mk* 81 * replies 82 */ 83 static void fuse_change_entry_timeout(struct dentry *entry, 84 struct fuse_entry_out *o) 85 { 86 fuse_dentry_settime(entry, 87 time_to_jiffies(o->entry_valid, o->entry_valid_nsec)); 88 } 89 90 static u64 attr_timeout(struct fuse_attr_out *o) 91 { 92 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec); 93 } 94 95 static u64 entry_attr_timeout(struct fuse_entry_out *o) 96 { 97 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec); 98 } 99 100 /* 101 * Mark the attributes as stale, so that at the next call to 102 * ->getattr() they will be fetched from userspace 103 */ 104 void fuse_invalidate_attr(struct inode *inode) 105 { 106 get_fuse_inode(inode)->i_time = 0; 107 } 108 109 /** 110 * Mark the attributes as stale due to an atime change. Avoid the invalidate if 111 * atime is not used. 112 */ 113 void fuse_invalidate_atime(struct inode *inode) 114 { 115 if (!IS_RDONLY(inode)) 116 fuse_invalidate_attr(inode); 117 } 118 119 /* 120 * Just mark the entry as stale, so that a next attempt to look it up 121 * will result in a new lookup call to userspace 122 * 123 * This is called when a dentry is about to become negative and the 124 * timeout is unknown (unlink, rmdir, rename and in some cases 125 * lookup) 126 */ 127 void fuse_invalidate_entry_cache(struct dentry *entry) 128 { 129 fuse_dentry_settime(entry, 0); 130 } 131 132 /* 133 * Same as fuse_invalidate_entry_cache(), but also try to remove the 134 * dentry from the hash 135 */ 136 static void fuse_invalidate_entry(struct dentry *entry) 137 { 138 d_invalidate(entry); 139 fuse_invalidate_entry_cache(entry); 140 } 141 142 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args, 143 u64 nodeid, const struct qstr *name, 144 struct fuse_entry_out *outarg) 145 { 146 memset(outarg, 0, sizeof(struct fuse_entry_out)); 147 args->in.h.opcode = FUSE_LOOKUP; 148 args->in.h.nodeid = nodeid; 149 args->in.numargs = 1; 150 args->in.args[0].size = name->len + 1; 151 args->in.args[0].value = name->name; 152 args->out.numargs = 1; 153 args->out.args[0].size = sizeof(struct fuse_entry_out); 154 args->out.args[0].value = outarg; 155 } 156 157 u64 fuse_get_attr_version(struct fuse_conn *fc) 158 { 159 u64 curr_version; 160 161 /* 162 * The spin lock isn't actually needed on 64bit archs, but we 163 * don't yet care too much about such optimizations. 164 */ 165 spin_lock(&fc->lock); 166 curr_version = fc->attr_version; 167 spin_unlock(&fc->lock); 168 169 return curr_version; 170 } 171 172 /* 173 * Check whether the dentry is still valid 174 * 175 * If the entry validity timeout has expired and the dentry is 176 * positive, try to redo the lookup. If the lookup results in a 177 * different inode, then let the VFS invalidate the dentry and redo 178 * the lookup once more. If the lookup results in the same inode, 179 * then refresh the attributes, timeouts and mark the dentry valid. 180 */ 181 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags) 182 { 183 struct inode *inode; 184 struct dentry *parent; 185 struct fuse_conn *fc; 186 struct fuse_inode *fi; 187 int ret; 188 189 inode = d_inode_rcu(entry); 190 if (inode && is_bad_inode(inode)) 191 goto invalid; 192 else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) || 193 (flags & LOOKUP_REVAL)) { 194 struct fuse_entry_out outarg; 195 FUSE_ARGS(args); 196 struct fuse_forget_link *forget; 197 u64 attr_version; 198 199 /* For negative dentries, always do a fresh lookup */ 200 if (!inode) 201 goto invalid; 202 203 ret = -ECHILD; 204 if (flags & LOOKUP_RCU) 205 goto out; 206 207 fc = get_fuse_conn(inode); 208 209 forget = fuse_alloc_forget(); 210 ret = -ENOMEM; 211 if (!forget) 212 goto out; 213 214 attr_version = fuse_get_attr_version(fc); 215 216 parent = dget_parent(entry); 217 fuse_lookup_init(fc, &args, get_node_id(d_inode(parent)), 218 &entry->d_name, &outarg); 219 ret = fuse_simple_request(fc, &args); 220 dput(parent); 221 /* Zero nodeid is same as -ENOENT */ 222 if (!ret && !outarg.nodeid) 223 ret = -ENOENT; 224 if (!ret) { 225 fi = get_fuse_inode(inode); 226 if (outarg.nodeid != get_node_id(inode)) { 227 fuse_queue_forget(fc, forget, outarg.nodeid, 1); 228 goto invalid; 229 } 230 spin_lock(&fc->lock); 231 fi->nlookup++; 232 spin_unlock(&fc->lock); 233 } 234 kfree(forget); 235 if (ret == -ENOMEM) 236 goto out; 237 if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT) 238 goto invalid; 239 240 forget_all_cached_acls(inode); 241 fuse_change_attributes(inode, &outarg.attr, 242 entry_attr_timeout(&outarg), 243 attr_version); 244 fuse_change_entry_timeout(entry, &outarg); 245 } else if (inode) { 246 fi = get_fuse_inode(inode); 247 if (flags & LOOKUP_RCU) { 248 if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state)) 249 return -ECHILD; 250 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) { 251 parent = dget_parent(entry); 252 fuse_advise_use_readdirplus(d_inode(parent)); 253 dput(parent); 254 } 255 } 256 ret = 1; 257 out: 258 return ret; 259 260 invalid: 261 ret = 0; 262 goto out; 263 } 264 265 static int invalid_nodeid(u64 nodeid) 266 { 267 return !nodeid || nodeid == FUSE_ROOT_ID; 268 } 269 270 static int fuse_dentry_init(struct dentry *dentry) 271 { 272 dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry), GFP_KERNEL); 273 274 return dentry->d_fsdata ? 0 : -ENOMEM; 275 } 276 static void fuse_dentry_release(struct dentry *dentry) 277 { 278 union fuse_dentry *fd = dentry->d_fsdata; 279 280 kfree_rcu(fd, rcu); 281 } 282 283 const struct dentry_operations fuse_dentry_operations = { 284 .d_revalidate = fuse_dentry_revalidate, 285 .d_init = fuse_dentry_init, 286 .d_release = fuse_dentry_release, 287 }; 288 289 const struct dentry_operations fuse_root_dentry_operations = { 290 .d_init = fuse_dentry_init, 291 .d_release = fuse_dentry_release, 292 }; 293 294 int fuse_valid_type(int m) 295 { 296 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) || 297 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m); 298 } 299 300 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name, 301 struct fuse_entry_out *outarg, struct inode **inode) 302 { 303 struct fuse_conn *fc = get_fuse_conn_super(sb); 304 FUSE_ARGS(args); 305 struct fuse_forget_link *forget; 306 u64 attr_version; 307 int err; 308 309 *inode = NULL; 310 err = -ENAMETOOLONG; 311 if (name->len > FUSE_NAME_MAX) 312 goto out; 313 314 315 forget = fuse_alloc_forget(); 316 err = -ENOMEM; 317 if (!forget) 318 goto out; 319 320 attr_version = fuse_get_attr_version(fc); 321 322 fuse_lookup_init(fc, &args, nodeid, name, outarg); 323 err = fuse_simple_request(fc, &args); 324 /* Zero nodeid is same as -ENOENT, but with valid timeout */ 325 if (err || !outarg->nodeid) 326 goto out_put_forget; 327 328 err = -EIO; 329 if (!outarg->nodeid) 330 goto out_put_forget; 331 if (!fuse_valid_type(outarg->attr.mode)) 332 goto out_put_forget; 333 334 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation, 335 &outarg->attr, entry_attr_timeout(outarg), 336 attr_version); 337 err = -ENOMEM; 338 if (!*inode) { 339 fuse_queue_forget(fc, forget, outarg->nodeid, 1); 340 goto out; 341 } 342 err = 0; 343 344 out_put_forget: 345 kfree(forget); 346 out: 347 return err; 348 } 349 350 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, 351 unsigned int flags) 352 { 353 int err; 354 struct fuse_entry_out outarg; 355 struct inode *inode; 356 struct dentry *newent; 357 bool outarg_valid = true; 358 359 fuse_lock_inode(dir); 360 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name, 361 &outarg, &inode); 362 fuse_unlock_inode(dir); 363 if (err == -ENOENT) { 364 outarg_valid = false; 365 err = 0; 366 } 367 if (err) 368 goto out_err; 369 370 err = -EIO; 371 if (inode && get_node_id(inode) == FUSE_ROOT_ID) 372 goto out_iput; 373 374 newent = d_splice_alias(inode, entry); 375 err = PTR_ERR(newent); 376 if (IS_ERR(newent)) 377 goto out_err; 378 379 entry = newent ? newent : entry; 380 if (outarg_valid) 381 fuse_change_entry_timeout(entry, &outarg); 382 else 383 fuse_invalidate_entry_cache(entry); 384 385 fuse_advise_use_readdirplus(dir); 386 return newent; 387 388 out_iput: 389 iput(inode); 390 out_err: 391 return ERR_PTR(err); 392 } 393 394 /* 395 * Atomic create+open operation 396 * 397 * If the filesystem doesn't support this, then fall back to separate 398 * 'mknod' + 'open' requests. 399 */ 400 static int fuse_create_open(struct inode *dir, struct dentry *entry, 401 struct file *file, unsigned flags, 402 umode_t mode, int *opened) 403 { 404 int err; 405 struct inode *inode; 406 struct fuse_conn *fc = get_fuse_conn(dir); 407 FUSE_ARGS(args); 408 struct fuse_forget_link *forget; 409 struct fuse_create_in inarg; 410 struct fuse_open_out outopen; 411 struct fuse_entry_out outentry; 412 struct fuse_file *ff; 413 414 /* Userspace expects S_IFREG in create mode */ 415 BUG_ON((mode & S_IFMT) != S_IFREG); 416 417 forget = fuse_alloc_forget(); 418 err = -ENOMEM; 419 if (!forget) 420 goto out_err; 421 422 err = -ENOMEM; 423 ff = fuse_file_alloc(fc); 424 if (!ff) 425 goto out_put_forget_req; 426 427 if (!fc->dont_mask) 428 mode &= ~current_umask(); 429 430 flags &= ~O_NOCTTY; 431 memset(&inarg, 0, sizeof(inarg)); 432 memset(&outentry, 0, sizeof(outentry)); 433 inarg.flags = flags; 434 inarg.mode = mode; 435 inarg.umask = current_umask(); 436 args.in.h.opcode = FUSE_CREATE; 437 args.in.h.nodeid = get_node_id(dir); 438 args.in.numargs = 2; 439 args.in.args[0].size = sizeof(inarg); 440 args.in.args[0].value = &inarg; 441 args.in.args[1].size = entry->d_name.len + 1; 442 args.in.args[1].value = entry->d_name.name; 443 args.out.numargs = 2; 444 args.out.args[0].size = sizeof(outentry); 445 args.out.args[0].value = &outentry; 446 args.out.args[1].size = sizeof(outopen); 447 args.out.args[1].value = &outopen; 448 err = fuse_simple_request(fc, &args); 449 if (err) 450 goto out_free_ff; 451 452 err = -EIO; 453 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid)) 454 goto out_free_ff; 455 456 ff->fh = outopen.fh; 457 ff->nodeid = outentry.nodeid; 458 ff->open_flags = outopen.open_flags; 459 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation, 460 &outentry.attr, entry_attr_timeout(&outentry), 0); 461 if (!inode) { 462 flags &= ~(O_CREAT | O_EXCL | O_TRUNC); 463 fuse_sync_release(ff, flags); 464 fuse_queue_forget(fc, forget, outentry.nodeid, 1); 465 err = -ENOMEM; 466 goto out_err; 467 } 468 kfree(forget); 469 d_instantiate(entry, inode); 470 fuse_change_entry_timeout(entry, &outentry); 471 fuse_invalidate_attr(dir); 472 err = finish_open(file, entry, generic_file_open, opened); 473 if (err) { 474 fuse_sync_release(ff, flags); 475 } else { 476 file->private_data = ff; 477 fuse_finish_open(inode, file); 478 } 479 return err; 480 481 out_free_ff: 482 fuse_file_free(ff); 483 out_put_forget_req: 484 kfree(forget); 485 out_err: 486 return err; 487 } 488 489 static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t); 490 static int fuse_atomic_open(struct inode *dir, struct dentry *entry, 491 struct file *file, unsigned flags, 492 umode_t mode, int *opened) 493 { 494 int err; 495 struct fuse_conn *fc = get_fuse_conn(dir); 496 struct dentry *res = NULL; 497 498 if (d_in_lookup(entry)) { 499 res = fuse_lookup(dir, entry, 0); 500 if (IS_ERR(res)) 501 return PTR_ERR(res); 502 503 if (res) 504 entry = res; 505 } 506 507 if (!(flags & O_CREAT) || d_really_is_positive(entry)) 508 goto no_open; 509 510 /* Only creates */ 511 *opened |= FILE_CREATED; 512 513 if (fc->no_create) 514 goto mknod; 515 516 err = fuse_create_open(dir, entry, file, flags, mode, opened); 517 if (err == -ENOSYS) { 518 fc->no_create = 1; 519 goto mknod; 520 } 521 out_dput: 522 dput(res); 523 return err; 524 525 mknod: 526 err = fuse_mknod(dir, entry, mode, 0); 527 if (err) 528 goto out_dput; 529 no_open: 530 return finish_no_open(file, res); 531 } 532 533 /* 534 * Code shared between mknod, mkdir, symlink and link 535 */ 536 static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args, 537 struct inode *dir, struct dentry *entry, 538 umode_t mode) 539 { 540 struct fuse_entry_out outarg; 541 struct inode *inode; 542 int err; 543 struct fuse_forget_link *forget; 544 545 forget = fuse_alloc_forget(); 546 if (!forget) 547 return -ENOMEM; 548 549 memset(&outarg, 0, sizeof(outarg)); 550 args->in.h.nodeid = get_node_id(dir); 551 args->out.numargs = 1; 552 args->out.args[0].size = sizeof(outarg); 553 args->out.args[0].value = &outarg; 554 err = fuse_simple_request(fc, args); 555 if (err) 556 goto out_put_forget_req; 557 558 err = -EIO; 559 if (invalid_nodeid(outarg.nodeid)) 560 goto out_put_forget_req; 561 562 if ((outarg.attr.mode ^ mode) & S_IFMT) 563 goto out_put_forget_req; 564 565 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation, 566 &outarg.attr, entry_attr_timeout(&outarg), 0); 567 if (!inode) { 568 fuse_queue_forget(fc, forget, outarg.nodeid, 1); 569 return -ENOMEM; 570 } 571 kfree(forget); 572 573 err = d_instantiate_no_diralias(entry, inode); 574 if (err) 575 return err; 576 577 fuse_change_entry_timeout(entry, &outarg); 578 fuse_invalidate_attr(dir); 579 return 0; 580 581 out_put_forget_req: 582 kfree(forget); 583 return err; 584 } 585 586 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode, 587 dev_t rdev) 588 { 589 struct fuse_mknod_in inarg; 590 struct fuse_conn *fc = get_fuse_conn(dir); 591 FUSE_ARGS(args); 592 593 if (!fc->dont_mask) 594 mode &= ~current_umask(); 595 596 memset(&inarg, 0, sizeof(inarg)); 597 inarg.mode = mode; 598 inarg.rdev = new_encode_dev(rdev); 599 inarg.umask = current_umask(); 600 args.in.h.opcode = FUSE_MKNOD; 601 args.in.numargs = 2; 602 args.in.args[0].size = sizeof(inarg); 603 args.in.args[0].value = &inarg; 604 args.in.args[1].size = entry->d_name.len + 1; 605 args.in.args[1].value = entry->d_name.name; 606 return create_new_entry(fc, &args, dir, entry, mode); 607 } 608 609 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode, 610 bool excl) 611 { 612 return fuse_mknod(dir, entry, mode, 0); 613 } 614 615 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode) 616 { 617 struct fuse_mkdir_in inarg; 618 struct fuse_conn *fc = get_fuse_conn(dir); 619 FUSE_ARGS(args); 620 621 if (!fc->dont_mask) 622 mode &= ~current_umask(); 623 624 memset(&inarg, 0, sizeof(inarg)); 625 inarg.mode = mode; 626 inarg.umask = current_umask(); 627 args.in.h.opcode = FUSE_MKDIR; 628 args.in.numargs = 2; 629 args.in.args[0].size = sizeof(inarg); 630 args.in.args[0].value = &inarg; 631 args.in.args[1].size = entry->d_name.len + 1; 632 args.in.args[1].value = entry->d_name.name; 633 return create_new_entry(fc, &args, dir, entry, S_IFDIR); 634 } 635 636 static int fuse_symlink(struct inode *dir, struct dentry *entry, 637 const char *link) 638 { 639 struct fuse_conn *fc = get_fuse_conn(dir); 640 unsigned len = strlen(link) + 1; 641 FUSE_ARGS(args); 642 643 args.in.h.opcode = FUSE_SYMLINK; 644 args.in.numargs = 2; 645 args.in.args[0].size = entry->d_name.len + 1; 646 args.in.args[0].value = entry->d_name.name; 647 args.in.args[1].size = len; 648 args.in.args[1].value = link; 649 return create_new_entry(fc, &args, dir, entry, S_IFLNK); 650 } 651 652 void fuse_update_ctime(struct inode *inode) 653 { 654 if (!IS_NOCMTIME(inode)) { 655 inode->i_ctime = current_time(inode); 656 mark_inode_dirty_sync(inode); 657 } 658 } 659 660 static int fuse_unlink(struct inode *dir, struct dentry *entry) 661 { 662 int err; 663 struct fuse_conn *fc = get_fuse_conn(dir); 664 FUSE_ARGS(args); 665 666 args.in.h.opcode = FUSE_UNLINK; 667 args.in.h.nodeid = get_node_id(dir); 668 args.in.numargs = 1; 669 args.in.args[0].size = entry->d_name.len + 1; 670 args.in.args[0].value = entry->d_name.name; 671 err = fuse_simple_request(fc, &args); 672 if (!err) { 673 struct inode *inode = d_inode(entry); 674 struct fuse_inode *fi = get_fuse_inode(inode); 675 676 spin_lock(&fc->lock); 677 fi->attr_version = ++fc->attr_version; 678 /* 679 * If i_nlink == 0 then unlink doesn't make sense, yet this can 680 * happen if userspace filesystem is careless. It would be 681 * difficult to enforce correct nlink usage so just ignore this 682 * condition here 683 */ 684 if (inode->i_nlink > 0) 685 drop_nlink(inode); 686 spin_unlock(&fc->lock); 687 fuse_invalidate_attr(inode); 688 fuse_invalidate_attr(dir); 689 fuse_invalidate_entry_cache(entry); 690 fuse_update_ctime(inode); 691 } else if (err == -EINTR) 692 fuse_invalidate_entry(entry); 693 return err; 694 } 695 696 static int fuse_rmdir(struct inode *dir, struct dentry *entry) 697 { 698 int err; 699 struct fuse_conn *fc = get_fuse_conn(dir); 700 FUSE_ARGS(args); 701 702 args.in.h.opcode = FUSE_RMDIR; 703 args.in.h.nodeid = get_node_id(dir); 704 args.in.numargs = 1; 705 args.in.args[0].size = entry->d_name.len + 1; 706 args.in.args[0].value = entry->d_name.name; 707 err = fuse_simple_request(fc, &args); 708 if (!err) { 709 clear_nlink(d_inode(entry)); 710 fuse_invalidate_attr(dir); 711 fuse_invalidate_entry_cache(entry); 712 } else if (err == -EINTR) 713 fuse_invalidate_entry(entry); 714 return err; 715 } 716 717 static int fuse_rename_common(struct inode *olddir, struct dentry *oldent, 718 struct inode *newdir, struct dentry *newent, 719 unsigned int flags, int opcode, size_t argsize) 720 { 721 int err; 722 struct fuse_rename2_in inarg; 723 struct fuse_conn *fc = get_fuse_conn(olddir); 724 FUSE_ARGS(args); 725 726 memset(&inarg, 0, argsize); 727 inarg.newdir = get_node_id(newdir); 728 inarg.flags = flags; 729 args.in.h.opcode = opcode; 730 args.in.h.nodeid = get_node_id(olddir); 731 args.in.numargs = 3; 732 args.in.args[0].size = argsize; 733 args.in.args[0].value = &inarg; 734 args.in.args[1].size = oldent->d_name.len + 1; 735 args.in.args[1].value = oldent->d_name.name; 736 args.in.args[2].size = newent->d_name.len + 1; 737 args.in.args[2].value = newent->d_name.name; 738 err = fuse_simple_request(fc, &args); 739 if (!err) { 740 /* ctime changes */ 741 fuse_invalidate_attr(d_inode(oldent)); 742 fuse_update_ctime(d_inode(oldent)); 743 744 if (flags & RENAME_EXCHANGE) { 745 fuse_invalidate_attr(d_inode(newent)); 746 fuse_update_ctime(d_inode(newent)); 747 } 748 749 fuse_invalidate_attr(olddir); 750 if (olddir != newdir) 751 fuse_invalidate_attr(newdir); 752 753 /* newent will end up negative */ 754 if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) { 755 fuse_invalidate_attr(d_inode(newent)); 756 fuse_invalidate_entry_cache(newent); 757 fuse_update_ctime(d_inode(newent)); 758 } 759 } else if (err == -EINTR) { 760 /* If request was interrupted, DEITY only knows if the 761 rename actually took place. If the invalidation 762 fails (e.g. some process has CWD under the renamed 763 directory), then there can be inconsistency between 764 the dcache and the real filesystem. Tough luck. */ 765 fuse_invalidate_entry(oldent); 766 if (d_really_is_positive(newent)) 767 fuse_invalidate_entry(newent); 768 } 769 770 return err; 771 } 772 773 static int fuse_rename2(struct inode *olddir, struct dentry *oldent, 774 struct inode *newdir, struct dentry *newent, 775 unsigned int flags) 776 { 777 struct fuse_conn *fc = get_fuse_conn(olddir); 778 int err; 779 780 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 781 return -EINVAL; 782 783 if (flags) { 784 if (fc->no_rename2 || fc->minor < 23) 785 return -EINVAL; 786 787 err = fuse_rename_common(olddir, oldent, newdir, newent, flags, 788 FUSE_RENAME2, 789 sizeof(struct fuse_rename2_in)); 790 if (err == -ENOSYS) { 791 fc->no_rename2 = 1; 792 err = -EINVAL; 793 } 794 } else { 795 err = fuse_rename_common(olddir, oldent, newdir, newent, 0, 796 FUSE_RENAME, 797 sizeof(struct fuse_rename_in)); 798 } 799 800 return err; 801 } 802 803 static int fuse_link(struct dentry *entry, struct inode *newdir, 804 struct dentry *newent) 805 { 806 int err; 807 struct fuse_link_in inarg; 808 struct inode *inode = d_inode(entry); 809 struct fuse_conn *fc = get_fuse_conn(inode); 810 FUSE_ARGS(args); 811 812 memset(&inarg, 0, sizeof(inarg)); 813 inarg.oldnodeid = get_node_id(inode); 814 args.in.h.opcode = FUSE_LINK; 815 args.in.numargs = 2; 816 args.in.args[0].size = sizeof(inarg); 817 args.in.args[0].value = &inarg; 818 args.in.args[1].size = newent->d_name.len + 1; 819 args.in.args[1].value = newent->d_name.name; 820 err = create_new_entry(fc, &args, newdir, newent, inode->i_mode); 821 /* Contrary to "normal" filesystems it can happen that link 822 makes two "logical" inodes point to the same "physical" 823 inode. We invalidate the attributes of the old one, so it 824 will reflect changes in the backing inode (link count, 825 etc.) 826 */ 827 if (!err) { 828 struct fuse_inode *fi = get_fuse_inode(inode); 829 830 spin_lock(&fc->lock); 831 fi->attr_version = ++fc->attr_version; 832 inc_nlink(inode); 833 spin_unlock(&fc->lock); 834 fuse_invalidate_attr(inode); 835 fuse_update_ctime(inode); 836 } else if (err == -EINTR) { 837 fuse_invalidate_attr(inode); 838 } 839 return err; 840 } 841 842 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr, 843 struct kstat *stat) 844 { 845 unsigned int blkbits; 846 struct fuse_conn *fc = get_fuse_conn(inode); 847 848 /* see the comment in fuse_change_attributes() */ 849 if (fc->writeback_cache && S_ISREG(inode->i_mode)) { 850 attr->size = i_size_read(inode); 851 attr->mtime = inode->i_mtime.tv_sec; 852 attr->mtimensec = inode->i_mtime.tv_nsec; 853 attr->ctime = inode->i_ctime.tv_sec; 854 attr->ctimensec = inode->i_ctime.tv_nsec; 855 } 856 857 stat->dev = inode->i_sb->s_dev; 858 stat->ino = attr->ino; 859 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 860 stat->nlink = attr->nlink; 861 stat->uid = make_kuid(fc->user_ns, attr->uid); 862 stat->gid = make_kgid(fc->user_ns, attr->gid); 863 stat->rdev = inode->i_rdev; 864 stat->atime.tv_sec = attr->atime; 865 stat->atime.tv_nsec = attr->atimensec; 866 stat->mtime.tv_sec = attr->mtime; 867 stat->mtime.tv_nsec = attr->mtimensec; 868 stat->ctime.tv_sec = attr->ctime; 869 stat->ctime.tv_nsec = attr->ctimensec; 870 stat->size = attr->size; 871 stat->blocks = attr->blocks; 872 873 if (attr->blksize != 0) 874 blkbits = ilog2(attr->blksize); 875 else 876 blkbits = inode->i_sb->s_blocksize_bits; 877 878 stat->blksize = 1 << blkbits; 879 } 880 881 static int fuse_do_getattr(struct inode *inode, struct kstat *stat, 882 struct file *file) 883 { 884 int err; 885 struct fuse_getattr_in inarg; 886 struct fuse_attr_out outarg; 887 struct fuse_conn *fc = get_fuse_conn(inode); 888 FUSE_ARGS(args); 889 u64 attr_version; 890 891 attr_version = fuse_get_attr_version(fc); 892 893 memset(&inarg, 0, sizeof(inarg)); 894 memset(&outarg, 0, sizeof(outarg)); 895 /* Directories have separate file-handle space */ 896 if (file && S_ISREG(inode->i_mode)) { 897 struct fuse_file *ff = file->private_data; 898 899 inarg.getattr_flags |= FUSE_GETATTR_FH; 900 inarg.fh = ff->fh; 901 } 902 args.in.h.opcode = FUSE_GETATTR; 903 args.in.h.nodeid = get_node_id(inode); 904 args.in.numargs = 1; 905 args.in.args[0].size = sizeof(inarg); 906 args.in.args[0].value = &inarg; 907 args.out.numargs = 1; 908 args.out.args[0].size = sizeof(outarg); 909 args.out.args[0].value = &outarg; 910 err = fuse_simple_request(fc, &args); 911 if (!err) { 912 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) { 913 make_bad_inode(inode); 914 err = -EIO; 915 } else { 916 fuse_change_attributes(inode, &outarg.attr, 917 attr_timeout(&outarg), 918 attr_version); 919 if (stat) 920 fuse_fillattr(inode, &outarg.attr, stat); 921 } 922 } 923 return err; 924 } 925 926 static int fuse_update_get_attr(struct inode *inode, struct file *file, 927 struct kstat *stat, unsigned int flags) 928 { 929 struct fuse_inode *fi = get_fuse_inode(inode); 930 int err = 0; 931 bool sync; 932 933 if (flags & AT_STATX_FORCE_SYNC) 934 sync = true; 935 else if (flags & AT_STATX_DONT_SYNC) 936 sync = false; 937 else 938 sync = time_before64(fi->i_time, get_jiffies_64()); 939 940 if (sync) { 941 forget_all_cached_acls(inode); 942 err = fuse_do_getattr(inode, stat, file); 943 } else if (stat) { 944 generic_fillattr(inode, stat); 945 stat->mode = fi->orig_i_mode; 946 stat->ino = fi->orig_ino; 947 } 948 949 return err; 950 } 951 952 int fuse_update_attributes(struct inode *inode, struct file *file) 953 { 954 return fuse_update_get_attr(inode, file, NULL, 0); 955 } 956 957 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, 958 u64 child_nodeid, struct qstr *name) 959 { 960 int err = -ENOTDIR; 961 struct inode *parent; 962 struct dentry *dir; 963 struct dentry *entry; 964 965 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid); 966 if (!parent) 967 return -ENOENT; 968 969 inode_lock(parent); 970 if (!S_ISDIR(parent->i_mode)) 971 goto unlock; 972 973 err = -ENOENT; 974 dir = d_find_alias(parent); 975 if (!dir) 976 goto unlock; 977 978 name->hash = full_name_hash(dir, name->name, name->len); 979 entry = d_lookup(dir, name); 980 dput(dir); 981 if (!entry) 982 goto unlock; 983 984 fuse_invalidate_attr(parent); 985 fuse_invalidate_entry(entry); 986 987 if (child_nodeid != 0 && d_really_is_positive(entry)) { 988 inode_lock(d_inode(entry)); 989 if (get_node_id(d_inode(entry)) != child_nodeid) { 990 err = -ENOENT; 991 goto badentry; 992 } 993 if (d_mountpoint(entry)) { 994 err = -EBUSY; 995 goto badentry; 996 } 997 if (d_is_dir(entry)) { 998 shrink_dcache_parent(entry); 999 if (!simple_empty(entry)) { 1000 err = -ENOTEMPTY; 1001 goto badentry; 1002 } 1003 d_inode(entry)->i_flags |= S_DEAD; 1004 } 1005 dont_mount(entry); 1006 clear_nlink(d_inode(entry)); 1007 err = 0; 1008 badentry: 1009 inode_unlock(d_inode(entry)); 1010 if (!err) 1011 d_delete(entry); 1012 } else { 1013 err = 0; 1014 } 1015 dput(entry); 1016 1017 unlock: 1018 inode_unlock(parent); 1019 iput(parent); 1020 return err; 1021 } 1022 1023 /* 1024 * Calling into a user-controlled filesystem gives the filesystem 1025 * daemon ptrace-like capabilities over the current process. This 1026 * means, that the filesystem daemon is able to record the exact 1027 * filesystem operations performed, and can also control the behavior 1028 * of the requester process in otherwise impossible ways. For example 1029 * it can delay the operation for arbitrary length of time allowing 1030 * DoS against the requester. 1031 * 1032 * For this reason only those processes can call into the filesystem, 1033 * for which the owner of the mount has ptrace privilege. This 1034 * excludes processes started by other users, suid or sgid processes. 1035 */ 1036 int fuse_allow_current_process(struct fuse_conn *fc) 1037 { 1038 const struct cred *cred; 1039 1040 if (fc->allow_other) 1041 return current_in_userns(fc->user_ns); 1042 1043 cred = current_cred(); 1044 if (uid_eq(cred->euid, fc->user_id) && 1045 uid_eq(cred->suid, fc->user_id) && 1046 uid_eq(cred->uid, fc->user_id) && 1047 gid_eq(cred->egid, fc->group_id) && 1048 gid_eq(cred->sgid, fc->group_id) && 1049 gid_eq(cred->gid, fc->group_id)) 1050 return 1; 1051 1052 return 0; 1053 } 1054 1055 static int fuse_access(struct inode *inode, int mask) 1056 { 1057 struct fuse_conn *fc = get_fuse_conn(inode); 1058 FUSE_ARGS(args); 1059 struct fuse_access_in inarg; 1060 int err; 1061 1062 BUG_ON(mask & MAY_NOT_BLOCK); 1063 1064 if (fc->no_access) 1065 return 0; 1066 1067 memset(&inarg, 0, sizeof(inarg)); 1068 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC); 1069 args.in.h.opcode = FUSE_ACCESS; 1070 args.in.h.nodeid = get_node_id(inode); 1071 args.in.numargs = 1; 1072 args.in.args[0].size = sizeof(inarg); 1073 args.in.args[0].value = &inarg; 1074 err = fuse_simple_request(fc, &args); 1075 if (err == -ENOSYS) { 1076 fc->no_access = 1; 1077 err = 0; 1078 } 1079 return err; 1080 } 1081 1082 static int fuse_perm_getattr(struct inode *inode, int mask) 1083 { 1084 if (mask & MAY_NOT_BLOCK) 1085 return -ECHILD; 1086 1087 forget_all_cached_acls(inode); 1088 return fuse_do_getattr(inode, NULL, NULL); 1089 } 1090 1091 /* 1092 * Check permission. The two basic access models of FUSE are: 1093 * 1094 * 1) Local access checking ('default_permissions' mount option) based 1095 * on file mode. This is the plain old disk filesystem permission 1096 * modell. 1097 * 1098 * 2) "Remote" access checking, where server is responsible for 1099 * checking permission in each inode operation. An exception to this 1100 * is if ->permission() was invoked from sys_access() in which case an 1101 * access request is sent. Execute permission is still checked 1102 * locally based on file mode. 1103 */ 1104 static int fuse_permission(struct inode *inode, int mask) 1105 { 1106 struct fuse_conn *fc = get_fuse_conn(inode); 1107 bool refreshed = false; 1108 int err = 0; 1109 1110 if (!fuse_allow_current_process(fc)) 1111 return -EACCES; 1112 1113 /* 1114 * If attributes are needed, refresh them before proceeding 1115 */ 1116 if (fc->default_permissions || 1117 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) { 1118 struct fuse_inode *fi = get_fuse_inode(inode); 1119 1120 if (time_before64(fi->i_time, get_jiffies_64())) { 1121 refreshed = true; 1122 1123 err = fuse_perm_getattr(inode, mask); 1124 if (err) 1125 return err; 1126 } 1127 } 1128 1129 if (fc->default_permissions) { 1130 err = generic_permission(inode, mask); 1131 1132 /* If permission is denied, try to refresh file 1133 attributes. This is also needed, because the root 1134 node will at first have no permissions */ 1135 if (err == -EACCES && !refreshed) { 1136 err = fuse_perm_getattr(inode, mask); 1137 if (!err) 1138 err = generic_permission(inode, mask); 1139 } 1140 1141 /* Note: the opposite of the above test does not 1142 exist. So if permissions are revoked this won't be 1143 noticed immediately, only after the attribute 1144 timeout has expired */ 1145 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) { 1146 err = fuse_access(inode, mask); 1147 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) { 1148 if (!(inode->i_mode & S_IXUGO)) { 1149 if (refreshed) 1150 return -EACCES; 1151 1152 err = fuse_perm_getattr(inode, mask); 1153 if (!err && !(inode->i_mode & S_IXUGO)) 1154 return -EACCES; 1155 } 1156 } 1157 return err; 1158 } 1159 1160 static int parse_dirfile(char *buf, size_t nbytes, struct file *file, 1161 struct dir_context *ctx) 1162 { 1163 while (nbytes >= FUSE_NAME_OFFSET) { 1164 struct fuse_dirent *dirent = (struct fuse_dirent *) buf; 1165 size_t reclen = FUSE_DIRENT_SIZE(dirent); 1166 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) 1167 return -EIO; 1168 if (reclen > nbytes) 1169 break; 1170 if (memchr(dirent->name, '/', dirent->namelen) != NULL) 1171 return -EIO; 1172 1173 if (!dir_emit(ctx, dirent->name, dirent->namelen, 1174 dirent->ino, dirent->type)) 1175 break; 1176 1177 buf += reclen; 1178 nbytes -= reclen; 1179 ctx->pos = dirent->off; 1180 } 1181 1182 return 0; 1183 } 1184 1185 static int fuse_direntplus_link(struct file *file, 1186 struct fuse_direntplus *direntplus, 1187 u64 attr_version) 1188 { 1189 struct fuse_entry_out *o = &direntplus->entry_out; 1190 struct fuse_dirent *dirent = &direntplus->dirent; 1191 struct dentry *parent = file->f_path.dentry; 1192 struct qstr name = QSTR_INIT(dirent->name, dirent->namelen); 1193 struct dentry *dentry; 1194 struct dentry *alias; 1195 struct inode *dir = d_inode(parent); 1196 struct fuse_conn *fc; 1197 struct inode *inode; 1198 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 1199 1200 if (!o->nodeid) { 1201 /* 1202 * Unlike in the case of fuse_lookup, zero nodeid does not mean 1203 * ENOENT. Instead, it only means the userspace filesystem did 1204 * not want to return attributes/handle for this entry. 1205 * 1206 * So do nothing. 1207 */ 1208 return 0; 1209 } 1210 1211 if (name.name[0] == '.') { 1212 /* 1213 * We could potentially refresh the attributes of the directory 1214 * and its parent? 1215 */ 1216 if (name.len == 1) 1217 return 0; 1218 if (name.name[1] == '.' && name.len == 2) 1219 return 0; 1220 } 1221 1222 if (invalid_nodeid(o->nodeid)) 1223 return -EIO; 1224 if (!fuse_valid_type(o->attr.mode)) 1225 return -EIO; 1226 1227 fc = get_fuse_conn(dir); 1228 1229 name.hash = full_name_hash(parent, name.name, name.len); 1230 dentry = d_lookup(parent, &name); 1231 if (!dentry) { 1232 retry: 1233 dentry = d_alloc_parallel(parent, &name, &wq); 1234 if (IS_ERR(dentry)) 1235 return PTR_ERR(dentry); 1236 } 1237 if (!d_in_lookup(dentry)) { 1238 struct fuse_inode *fi; 1239 inode = d_inode(dentry); 1240 if (!inode || 1241 get_node_id(inode) != o->nodeid || 1242 ((o->attr.mode ^ inode->i_mode) & S_IFMT)) { 1243 d_invalidate(dentry); 1244 dput(dentry); 1245 goto retry; 1246 } 1247 if (is_bad_inode(inode)) { 1248 dput(dentry); 1249 return -EIO; 1250 } 1251 1252 fi = get_fuse_inode(inode); 1253 spin_lock(&fc->lock); 1254 fi->nlookup++; 1255 spin_unlock(&fc->lock); 1256 1257 forget_all_cached_acls(inode); 1258 fuse_change_attributes(inode, &o->attr, 1259 entry_attr_timeout(o), 1260 attr_version); 1261 /* 1262 * The other branch comes via fuse_iget() 1263 * which bumps nlookup inside 1264 */ 1265 } else { 1266 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation, 1267 &o->attr, entry_attr_timeout(o), 1268 attr_version); 1269 if (!inode) 1270 inode = ERR_PTR(-ENOMEM); 1271 1272 alias = d_splice_alias(inode, dentry); 1273 d_lookup_done(dentry); 1274 if (alias) { 1275 dput(dentry); 1276 dentry = alias; 1277 } 1278 if (IS_ERR(dentry)) 1279 return PTR_ERR(dentry); 1280 } 1281 if (fc->readdirplus_auto) 1282 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state); 1283 fuse_change_entry_timeout(dentry, o); 1284 1285 dput(dentry); 1286 return 0; 1287 } 1288 1289 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file, 1290 struct dir_context *ctx, u64 attr_version) 1291 { 1292 struct fuse_direntplus *direntplus; 1293 struct fuse_dirent *dirent; 1294 size_t reclen; 1295 int over = 0; 1296 int ret; 1297 1298 while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) { 1299 direntplus = (struct fuse_direntplus *) buf; 1300 dirent = &direntplus->dirent; 1301 reclen = FUSE_DIRENTPLUS_SIZE(direntplus); 1302 1303 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) 1304 return -EIO; 1305 if (reclen > nbytes) 1306 break; 1307 if (memchr(dirent->name, '/', dirent->namelen) != NULL) 1308 return -EIO; 1309 1310 if (!over) { 1311 /* We fill entries into dstbuf only as much as 1312 it can hold. But we still continue iterating 1313 over remaining entries to link them. If not, 1314 we need to send a FORGET for each of those 1315 which we did not link. 1316 */ 1317 over = !dir_emit(ctx, dirent->name, dirent->namelen, 1318 dirent->ino, dirent->type); 1319 if (!over) 1320 ctx->pos = dirent->off; 1321 } 1322 1323 buf += reclen; 1324 nbytes -= reclen; 1325 1326 ret = fuse_direntplus_link(file, direntplus, attr_version); 1327 if (ret) 1328 fuse_force_forget(file, direntplus->entry_out.nodeid); 1329 } 1330 1331 return 0; 1332 } 1333 1334 static int fuse_readdir(struct file *file, struct dir_context *ctx) 1335 { 1336 int plus, err; 1337 size_t nbytes; 1338 struct page *page; 1339 struct inode *inode = file_inode(file); 1340 struct fuse_conn *fc = get_fuse_conn(inode); 1341 struct fuse_req *req; 1342 u64 attr_version = 0; 1343 1344 if (is_bad_inode(inode)) 1345 return -EIO; 1346 1347 req = fuse_get_req(fc, 1); 1348 if (IS_ERR(req)) 1349 return PTR_ERR(req); 1350 1351 page = alloc_page(GFP_KERNEL); 1352 if (!page) { 1353 fuse_put_request(fc, req); 1354 return -ENOMEM; 1355 } 1356 1357 plus = fuse_use_readdirplus(inode, ctx); 1358 req->out.argpages = 1; 1359 req->num_pages = 1; 1360 req->pages[0] = page; 1361 req->page_descs[0].length = PAGE_SIZE; 1362 if (plus) { 1363 attr_version = fuse_get_attr_version(fc); 1364 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, 1365 FUSE_READDIRPLUS); 1366 } else { 1367 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, 1368 FUSE_READDIR); 1369 } 1370 fuse_lock_inode(inode); 1371 fuse_request_send(fc, req); 1372 fuse_unlock_inode(inode); 1373 nbytes = req->out.args[0].size; 1374 err = req->out.h.error; 1375 fuse_put_request(fc, req); 1376 if (!err) { 1377 if (plus) { 1378 err = parse_dirplusfile(page_address(page), nbytes, 1379 file, ctx, 1380 attr_version); 1381 } else { 1382 err = parse_dirfile(page_address(page), nbytes, file, 1383 ctx); 1384 } 1385 } 1386 1387 __free_page(page); 1388 fuse_invalidate_atime(inode); 1389 return err; 1390 } 1391 1392 static const char *fuse_get_link(struct dentry *dentry, 1393 struct inode *inode, 1394 struct delayed_call *done) 1395 { 1396 struct fuse_conn *fc = get_fuse_conn(inode); 1397 FUSE_ARGS(args); 1398 char *link; 1399 ssize_t ret; 1400 1401 if (!dentry) 1402 return ERR_PTR(-ECHILD); 1403 1404 link = kmalloc(PAGE_SIZE, GFP_KERNEL); 1405 if (!link) 1406 return ERR_PTR(-ENOMEM); 1407 1408 args.in.h.opcode = FUSE_READLINK; 1409 args.in.h.nodeid = get_node_id(inode); 1410 args.out.argvar = 1; 1411 args.out.numargs = 1; 1412 args.out.args[0].size = PAGE_SIZE - 1; 1413 args.out.args[0].value = link; 1414 ret = fuse_simple_request(fc, &args); 1415 if (ret < 0) { 1416 kfree(link); 1417 link = ERR_PTR(ret); 1418 } else { 1419 link[ret] = '\0'; 1420 set_delayed_call(done, kfree_link, link); 1421 } 1422 fuse_invalidate_atime(inode); 1423 return link; 1424 } 1425 1426 static int fuse_dir_open(struct inode *inode, struct file *file) 1427 { 1428 return fuse_open_common(inode, file, true); 1429 } 1430 1431 static int fuse_dir_release(struct inode *inode, struct file *file) 1432 { 1433 fuse_release_common(file, FUSE_RELEASEDIR); 1434 1435 return 0; 1436 } 1437 1438 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end, 1439 int datasync) 1440 { 1441 return fuse_fsync_common(file, start, end, datasync, 1); 1442 } 1443 1444 static long fuse_dir_ioctl(struct file *file, unsigned int cmd, 1445 unsigned long arg) 1446 { 1447 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host); 1448 1449 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */ 1450 if (fc->minor < 18) 1451 return -ENOTTY; 1452 1453 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR); 1454 } 1455 1456 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd, 1457 unsigned long arg) 1458 { 1459 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host); 1460 1461 if (fc->minor < 18) 1462 return -ENOTTY; 1463 1464 return fuse_ioctl_common(file, cmd, arg, 1465 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR); 1466 } 1467 1468 static bool update_mtime(unsigned ivalid, bool trust_local_mtime) 1469 { 1470 /* Always update if mtime is explicitly set */ 1471 if (ivalid & ATTR_MTIME_SET) 1472 return true; 1473 1474 /* Or if kernel i_mtime is the official one */ 1475 if (trust_local_mtime) 1476 return true; 1477 1478 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */ 1479 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE))) 1480 return false; 1481 1482 /* In all other cases update */ 1483 return true; 1484 } 1485 1486 static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr, 1487 struct fuse_setattr_in *arg, bool trust_local_cmtime) 1488 { 1489 unsigned ivalid = iattr->ia_valid; 1490 1491 if (ivalid & ATTR_MODE) 1492 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode; 1493 if (ivalid & ATTR_UID) 1494 arg->valid |= FATTR_UID, arg->uid = from_kuid(fc->user_ns, iattr->ia_uid); 1495 if (ivalid & ATTR_GID) 1496 arg->valid |= FATTR_GID, arg->gid = from_kgid(fc->user_ns, iattr->ia_gid); 1497 if (ivalid & ATTR_SIZE) 1498 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size; 1499 if (ivalid & ATTR_ATIME) { 1500 arg->valid |= FATTR_ATIME; 1501 arg->atime = iattr->ia_atime.tv_sec; 1502 arg->atimensec = iattr->ia_atime.tv_nsec; 1503 if (!(ivalid & ATTR_ATIME_SET)) 1504 arg->valid |= FATTR_ATIME_NOW; 1505 } 1506 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) { 1507 arg->valid |= FATTR_MTIME; 1508 arg->mtime = iattr->ia_mtime.tv_sec; 1509 arg->mtimensec = iattr->ia_mtime.tv_nsec; 1510 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime) 1511 arg->valid |= FATTR_MTIME_NOW; 1512 } 1513 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) { 1514 arg->valid |= FATTR_CTIME; 1515 arg->ctime = iattr->ia_ctime.tv_sec; 1516 arg->ctimensec = iattr->ia_ctime.tv_nsec; 1517 } 1518 } 1519 1520 /* 1521 * Prevent concurrent writepages on inode 1522 * 1523 * This is done by adding a negative bias to the inode write counter 1524 * and waiting for all pending writes to finish. 1525 */ 1526 void fuse_set_nowrite(struct inode *inode) 1527 { 1528 struct fuse_conn *fc = get_fuse_conn(inode); 1529 struct fuse_inode *fi = get_fuse_inode(inode); 1530 1531 BUG_ON(!inode_is_locked(inode)); 1532 1533 spin_lock(&fc->lock); 1534 BUG_ON(fi->writectr < 0); 1535 fi->writectr += FUSE_NOWRITE; 1536 spin_unlock(&fc->lock); 1537 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE); 1538 } 1539 1540 /* 1541 * Allow writepages on inode 1542 * 1543 * Remove the bias from the writecounter and send any queued 1544 * writepages. 1545 */ 1546 static void __fuse_release_nowrite(struct inode *inode) 1547 { 1548 struct fuse_inode *fi = get_fuse_inode(inode); 1549 1550 BUG_ON(fi->writectr != FUSE_NOWRITE); 1551 fi->writectr = 0; 1552 fuse_flush_writepages(inode); 1553 } 1554 1555 void fuse_release_nowrite(struct inode *inode) 1556 { 1557 struct fuse_conn *fc = get_fuse_conn(inode); 1558 1559 spin_lock(&fc->lock); 1560 __fuse_release_nowrite(inode); 1561 spin_unlock(&fc->lock); 1562 } 1563 1564 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args, 1565 struct inode *inode, 1566 struct fuse_setattr_in *inarg_p, 1567 struct fuse_attr_out *outarg_p) 1568 { 1569 args->in.h.opcode = FUSE_SETATTR; 1570 args->in.h.nodeid = get_node_id(inode); 1571 args->in.numargs = 1; 1572 args->in.args[0].size = sizeof(*inarg_p); 1573 args->in.args[0].value = inarg_p; 1574 args->out.numargs = 1; 1575 args->out.args[0].size = sizeof(*outarg_p); 1576 args->out.args[0].value = outarg_p; 1577 } 1578 1579 /* 1580 * Flush inode->i_mtime to the server 1581 */ 1582 int fuse_flush_times(struct inode *inode, struct fuse_file *ff) 1583 { 1584 struct fuse_conn *fc = get_fuse_conn(inode); 1585 FUSE_ARGS(args); 1586 struct fuse_setattr_in inarg; 1587 struct fuse_attr_out outarg; 1588 1589 memset(&inarg, 0, sizeof(inarg)); 1590 memset(&outarg, 0, sizeof(outarg)); 1591 1592 inarg.valid = FATTR_MTIME; 1593 inarg.mtime = inode->i_mtime.tv_sec; 1594 inarg.mtimensec = inode->i_mtime.tv_nsec; 1595 if (fc->minor >= 23) { 1596 inarg.valid |= FATTR_CTIME; 1597 inarg.ctime = inode->i_ctime.tv_sec; 1598 inarg.ctimensec = inode->i_ctime.tv_nsec; 1599 } 1600 if (ff) { 1601 inarg.valid |= FATTR_FH; 1602 inarg.fh = ff->fh; 1603 } 1604 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg); 1605 1606 return fuse_simple_request(fc, &args); 1607 } 1608 1609 /* 1610 * Set attributes, and at the same time refresh them. 1611 * 1612 * Truncation is slightly complicated, because the 'truncate' request 1613 * may fail, in which case we don't want to touch the mapping. 1614 * vmtruncate() doesn't allow for this case, so do the rlimit checking 1615 * and the actual truncation by hand. 1616 */ 1617 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, 1618 struct file *file) 1619 { 1620 struct inode *inode = d_inode(dentry); 1621 struct fuse_conn *fc = get_fuse_conn(inode); 1622 struct fuse_inode *fi = get_fuse_inode(inode); 1623 FUSE_ARGS(args); 1624 struct fuse_setattr_in inarg; 1625 struct fuse_attr_out outarg; 1626 bool is_truncate = false; 1627 bool is_wb = fc->writeback_cache; 1628 loff_t oldsize; 1629 int err; 1630 bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode); 1631 1632 if (!fc->default_permissions) 1633 attr->ia_valid |= ATTR_FORCE; 1634 1635 err = setattr_prepare(dentry, attr); 1636 if (err) 1637 return err; 1638 1639 if (attr->ia_valid & ATTR_OPEN) { 1640 /* This is coming from open(..., ... | O_TRUNC); */ 1641 WARN_ON(!(attr->ia_valid & ATTR_SIZE)); 1642 WARN_ON(attr->ia_size != 0); 1643 if (fc->atomic_o_trunc) { 1644 /* 1645 * No need to send request to userspace, since actual 1646 * truncation has already been done by OPEN. But still 1647 * need to truncate page cache. 1648 */ 1649 i_size_write(inode, 0); 1650 truncate_pagecache(inode, 0); 1651 return 0; 1652 } 1653 file = NULL; 1654 } 1655 1656 if (attr->ia_valid & ATTR_SIZE) 1657 is_truncate = true; 1658 1659 if (is_truncate) { 1660 fuse_set_nowrite(inode); 1661 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); 1662 if (trust_local_cmtime && attr->ia_size != inode->i_size) 1663 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME; 1664 } 1665 1666 memset(&inarg, 0, sizeof(inarg)); 1667 memset(&outarg, 0, sizeof(outarg)); 1668 iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime); 1669 if (file) { 1670 struct fuse_file *ff = file->private_data; 1671 inarg.valid |= FATTR_FH; 1672 inarg.fh = ff->fh; 1673 } 1674 if (attr->ia_valid & ATTR_SIZE) { 1675 /* For mandatory locking in truncate */ 1676 inarg.valid |= FATTR_LOCKOWNER; 1677 inarg.lock_owner = fuse_lock_owner_id(fc, current->files); 1678 } 1679 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg); 1680 err = fuse_simple_request(fc, &args); 1681 if (err) { 1682 if (err == -EINTR) 1683 fuse_invalidate_attr(inode); 1684 goto error; 1685 } 1686 1687 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) { 1688 make_bad_inode(inode); 1689 err = -EIO; 1690 goto error; 1691 } 1692 1693 spin_lock(&fc->lock); 1694 /* the kernel maintains i_mtime locally */ 1695 if (trust_local_cmtime) { 1696 if (attr->ia_valid & ATTR_MTIME) 1697 inode->i_mtime = attr->ia_mtime; 1698 if (attr->ia_valid & ATTR_CTIME) 1699 inode->i_ctime = attr->ia_ctime; 1700 /* FIXME: clear I_DIRTY_SYNC? */ 1701 } 1702 1703 fuse_change_attributes_common(inode, &outarg.attr, 1704 attr_timeout(&outarg)); 1705 oldsize = inode->i_size; 1706 /* see the comment in fuse_change_attributes() */ 1707 if (!is_wb || is_truncate || !S_ISREG(inode->i_mode)) 1708 i_size_write(inode, outarg.attr.size); 1709 1710 if (is_truncate) { 1711 /* NOTE: this may release/reacquire fc->lock */ 1712 __fuse_release_nowrite(inode); 1713 } 1714 spin_unlock(&fc->lock); 1715 1716 /* 1717 * Only call invalidate_inode_pages2() after removing 1718 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock. 1719 */ 1720 if ((is_truncate || !is_wb) && 1721 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) { 1722 truncate_pagecache(inode, outarg.attr.size); 1723 invalidate_inode_pages2(inode->i_mapping); 1724 } 1725 1726 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); 1727 return 0; 1728 1729 error: 1730 if (is_truncate) 1731 fuse_release_nowrite(inode); 1732 1733 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); 1734 return err; 1735 } 1736 1737 static int fuse_setattr(struct dentry *entry, struct iattr *attr) 1738 { 1739 struct inode *inode = d_inode(entry); 1740 struct fuse_conn *fc = get_fuse_conn(inode); 1741 struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL; 1742 int ret; 1743 1744 if (!fuse_allow_current_process(get_fuse_conn(inode))) 1745 return -EACCES; 1746 1747 if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) { 1748 attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | 1749 ATTR_MODE); 1750 1751 /* 1752 * The only sane way to reliably kill suid/sgid is to do it in 1753 * the userspace filesystem 1754 * 1755 * This should be done on write(), truncate() and chown(). 1756 */ 1757 if (!fc->handle_killpriv) { 1758 /* 1759 * ia_mode calculation may have used stale i_mode. 1760 * Refresh and recalculate. 1761 */ 1762 ret = fuse_do_getattr(inode, NULL, file); 1763 if (ret) 1764 return ret; 1765 1766 attr->ia_mode = inode->i_mode; 1767 if (inode->i_mode & S_ISUID) { 1768 attr->ia_valid |= ATTR_MODE; 1769 attr->ia_mode &= ~S_ISUID; 1770 } 1771 if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { 1772 attr->ia_valid |= ATTR_MODE; 1773 attr->ia_mode &= ~S_ISGID; 1774 } 1775 } 1776 } 1777 if (!attr->ia_valid) 1778 return 0; 1779 1780 ret = fuse_do_setattr(entry, attr, file); 1781 if (!ret) { 1782 /* 1783 * If filesystem supports acls it may have updated acl xattrs in 1784 * the filesystem, so forget cached acls for the inode. 1785 */ 1786 if (fc->posix_acl) 1787 forget_all_cached_acls(inode); 1788 1789 /* Directory mode changed, may need to revalidate access */ 1790 if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE)) 1791 fuse_invalidate_entry_cache(entry); 1792 } 1793 return ret; 1794 } 1795 1796 static int fuse_getattr(const struct path *path, struct kstat *stat, 1797 u32 request_mask, unsigned int flags) 1798 { 1799 struct inode *inode = d_inode(path->dentry); 1800 struct fuse_conn *fc = get_fuse_conn(inode); 1801 1802 if (!fuse_allow_current_process(fc)) 1803 return -EACCES; 1804 1805 return fuse_update_get_attr(inode, NULL, stat, flags); 1806 } 1807 1808 static const struct inode_operations fuse_dir_inode_operations = { 1809 .lookup = fuse_lookup, 1810 .mkdir = fuse_mkdir, 1811 .symlink = fuse_symlink, 1812 .unlink = fuse_unlink, 1813 .rmdir = fuse_rmdir, 1814 .rename = fuse_rename2, 1815 .link = fuse_link, 1816 .setattr = fuse_setattr, 1817 .create = fuse_create, 1818 .atomic_open = fuse_atomic_open, 1819 .mknod = fuse_mknod, 1820 .permission = fuse_permission, 1821 .getattr = fuse_getattr, 1822 .listxattr = fuse_listxattr, 1823 .get_acl = fuse_get_acl, 1824 .set_acl = fuse_set_acl, 1825 }; 1826 1827 static const struct file_operations fuse_dir_operations = { 1828 .llseek = generic_file_llseek, 1829 .read = generic_read_dir, 1830 .iterate_shared = fuse_readdir, 1831 .open = fuse_dir_open, 1832 .release = fuse_dir_release, 1833 .fsync = fuse_dir_fsync, 1834 .unlocked_ioctl = fuse_dir_ioctl, 1835 .compat_ioctl = fuse_dir_compat_ioctl, 1836 }; 1837 1838 static const struct inode_operations fuse_common_inode_operations = { 1839 .setattr = fuse_setattr, 1840 .permission = fuse_permission, 1841 .getattr = fuse_getattr, 1842 .listxattr = fuse_listxattr, 1843 .get_acl = fuse_get_acl, 1844 .set_acl = fuse_set_acl, 1845 }; 1846 1847 static const struct inode_operations fuse_symlink_inode_operations = { 1848 .setattr = fuse_setattr, 1849 .get_link = fuse_get_link, 1850 .getattr = fuse_getattr, 1851 .listxattr = fuse_listxattr, 1852 }; 1853 1854 void fuse_init_common(struct inode *inode) 1855 { 1856 inode->i_op = &fuse_common_inode_operations; 1857 } 1858 1859 void fuse_init_dir(struct inode *inode) 1860 { 1861 inode->i_op = &fuse_dir_inode_operations; 1862 inode->i_fop = &fuse_dir_operations; 1863 } 1864 1865 void fuse_init_symlink(struct inode *inode) 1866 { 1867 inode->i_op = &fuse_symlink_inode_operations; 1868 } 1869