1 /* 2 * 3 * Copyright (C) 2011 Novell Inc. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 as published by 7 * the Free Software Foundation. 8 */ 9 10 #include <linux/fs.h> 11 #include <linux/namei.h> 12 #include <linux/xattr.h> 13 #include <linux/security.h> 14 #include <linux/cred.h> 15 #include "overlayfs.h" 16 17 void ovl_cleanup(struct inode *wdir, struct dentry *wdentry) 18 { 19 int err; 20 21 dget(wdentry); 22 if (d_is_dir(wdentry)) 23 err = ovl_do_rmdir(wdir, wdentry); 24 else 25 err = ovl_do_unlink(wdir, wdentry); 26 dput(wdentry); 27 28 if (err) { 29 pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n", 30 wdentry, err); 31 } 32 } 33 34 struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry) 35 { 36 struct dentry *temp; 37 char name[20]; 38 39 snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry); 40 41 temp = lookup_one_len(name, workdir, strlen(name)); 42 if (!IS_ERR(temp) && temp->d_inode) { 43 pr_err("overlayfs: workdir/%s already exists\n", name); 44 dput(temp); 45 temp = ERR_PTR(-EIO); 46 } 47 48 return temp; 49 } 50 51 /* caller holds i_mutex on workdir */ 52 static struct dentry *ovl_whiteout(struct dentry *workdir, 53 struct dentry *dentry) 54 { 55 int err; 56 struct dentry *whiteout; 57 struct inode *wdir = workdir->d_inode; 58 59 whiteout = ovl_lookup_temp(workdir, dentry); 60 if (IS_ERR(whiteout)) 61 return whiteout; 62 63 err = ovl_do_whiteout(wdir, whiteout); 64 if (err) { 65 dput(whiteout); 66 whiteout = ERR_PTR(err); 67 } 68 69 return whiteout; 70 } 71 72 int ovl_create_real(struct inode *dir, struct dentry *newdentry, 73 struct kstat *stat, const char *link, 74 struct dentry *hardlink, bool debug) 75 { 76 int err; 77 78 if (newdentry->d_inode) 79 return -ESTALE; 80 81 if (hardlink) { 82 err = ovl_do_link(hardlink, dir, newdentry, debug); 83 } else { 84 switch (stat->mode & S_IFMT) { 85 case S_IFREG: 86 err = ovl_do_create(dir, newdentry, stat->mode, debug); 87 break; 88 89 case S_IFDIR: 90 err = ovl_do_mkdir(dir, newdentry, stat->mode, debug); 91 break; 92 93 case S_IFCHR: 94 case S_IFBLK: 95 case S_IFIFO: 96 case S_IFSOCK: 97 err = ovl_do_mknod(dir, newdentry, 98 stat->mode, stat->rdev, debug); 99 break; 100 101 case S_IFLNK: 102 err = ovl_do_symlink(dir, newdentry, link, debug); 103 break; 104 105 default: 106 err = -EPERM; 107 } 108 } 109 if (!err && WARN_ON(!newdentry->d_inode)) { 110 /* 111 * Not quite sure if non-instantiated dentry is legal or not. 112 * VFS doesn't seem to care so check and warn here. 113 */ 114 err = -ENOENT; 115 } 116 return err; 117 } 118 119 static int ovl_set_opaque(struct dentry *upperdentry) 120 { 121 return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0); 122 } 123 124 static void ovl_remove_opaque(struct dentry *upperdentry) 125 { 126 int err; 127 128 err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE); 129 if (err) { 130 pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n", 131 upperdentry->d_name.name, err); 132 } 133 } 134 135 static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, 136 struct kstat *stat) 137 { 138 int err; 139 enum ovl_path_type type; 140 struct path realpath; 141 142 type = ovl_path_real(dentry, &realpath); 143 err = vfs_getattr(&realpath, stat); 144 if (err) 145 return err; 146 147 stat->dev = dentry->d_sb->s_dev; 148 stat->ino = dentry->d_inode->i_ino; 149 150 /* 151 * It's probably not worth it to count subdirs to get the 152 * correct link count. nlink=1 seems to pacify 'find' and 153 * other utilities. 154 */ 155 if (OVL_TYPE_MERGE(type)) 156 stat->nlink = 1; 157 158 return 0; 159 } 160 161 static int ovl_create_upper(struct dentry *dentry, struct inode *inode, 162 struct kstat *stat, const char *link, 163 struct dentry *hardlink) 164 { 165 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); 166 struct inode *udir = upperdir->d_inode; 167 struct dentry *newdentry; 168 int err; 169 170 inode_lock_nested(udir, I_MUTEX_PARENT); 171 newdentry = lookup_one_len(dentry->d_name.name, upperdir, 172 dentry->d_name.len); 173 err = PTR_ERR(newdentry); 174 if (IS_ERR(newdentry)) 175 goto out_unlock; 176 err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); 177 if (err) 178 goto out_dput; 179 180 ovl_dentry_version_inc(dentry->d_parent); 181 ovl_dentry_update(dentry, newdentry); 182 ovl_copyattr(newdentry->d_inode, inode); 183 d_instantiate(dentry, inode); 184 newdentry = NULL; 185 out_dput: 186 dput(newdentry); 187 out_unlock: 188 inode_unlock(udir); 189 return err; 190 } 191 192 static int ovl_lock_rename_workdir(struct dentry *workdir, 193 struct dentry *upperdir) 194 { 195 /* Workdir should not be the same as upperdir */ 196 if (workdir == upperdir) 197 goto err; 198 199 /* Workdir should not be subdir of upperdir and vice versa */ 200 if (lock_rename(workdir, upperdir) != NULL) 201 goto err_unlock; 202 203 return 0; 204 205 err_unlock: 206 unlock_rename(workdir, upperdir); 207 err: 208 pr_err("overlayfs: failed to lock workdir+upperdir\n"); 209 return -EIO; 210 } 211 212 static struct dentry *ovl_clear_empty(struct dentry *dentry, 213 struct list_head *list) 214 { 215 struct dentry *workdir = ovl_workdir(dentry); 216 struct inode *wdir = workdir->d_inode; 217 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); 218 struct inode *udir = upperdir->d_inode; 219 struct path upperpath; 220 struct dentry *upper; 221 struct dentry *opaquedir; 222 struct kstat stat; 223 int err; 224 225 if (WARN_ON(!workdir)) 226 return ERR_PTR(-EROFS); 227 228 err = ovl_lock_rename_workdir(workdir, upperdir); 229 if (err) 230 goto out; 231 232 ovl_path_upper(dentry, &upperpath); 233 err = vfs_getattr(&upperpath, &stat); 234 if (err) 235 goto out_unlock; 236 237 err = -ESTALE; 238 if (!S_ISDIR(stat.mode)) 239 goto out_unlock; 240 upper = upperpath.dentry; 241 if (upper->d_parent->d_inode != udir) 242 goto out_unlock; 243 244 opaquedir = ovl_lookup_temp(workdir, dentry); 245 err = PTR_ERR(opaquedir); 246 if (IS_ERR(opaquedir)) 247 goto out_unlock; 248 249 err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); 250 if (err) 251 goto out_dput; 252 253 err = ovl_copy_xattr(upper, opaquedir); 254 if (err) 255 goto out_cleanup; 256 257 err = ovl_set_opaque(opaquedir); 258 if (err) 259 goto out_cleanup; 260 261 inode_lock(opaquedir->d_inode); 262 err = ovl_set_attr(opaquedir, &stat); 263 inode_unlock(opaquedir->d_inode); 264 if (err) 265 goto out_cleanup; 266 267 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); 268 if (err) 269 goto out_cleanup; 270 271 ovl_cleanup_whiteouts(upper, list); 272 ovl_cleanup(wdir, upper); 273 unlock_rename(workdir, upperdir); 274 275 /* dentry's upper doesn't match now, get rid of it */ 276 d_drop(dentry); 277 278 return opaquedir; 279 280 out_cleanup: 281 ovl_cleanup(wdir, opaquedir); 282 out_dput: 283 dput(opaquedir); 284 out_unlock: 285 unlock_rename(workdir, upperdir); 286 out: 287 return ERR_PTR(err); 288 } 289 290 static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) 291 { 292 int err; 293 struct dentry *ret = NULL; 294 LIST_HEAD(list); 295 296 err = ovl_check_empty_dir(dentry, &list); 297 if (err) 298 ret = ERR_PTR(err); 299 else { 300 /* 301 * If no upperdentry then skip clearing whiteouts. 302 * 303 * Can race with copy-up, since we don't hold the upperdir 304 * mutex. Doesn't matter, since copy-up can't create a 305 * non-empty directory from an empty one. 306 */ 307 if (ovl_dentry_upper(dentry)) 308 ret = ovl_clear_empty(dentry, &list); 309 } 310 311 ovl_cache_free(&list); 312 313 return ret; 314 } 315 316 static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, 317 struct kstat *stat, const char *link, 318 struct dentry *hardlink) 319 { 320 struct dentry *workdir = ovl_workdir(dentry); 321 struct inode *wdir = workdir->d_inode; 322 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); 323 struct inode *udir = upperdir->d_inode; 324 struct dentry *upper; 325 struct dentry *newdentry; 326 int err; 327 328 if (WARN_ON(!workdir)) 329 return -EROFS; 330 331 err = ovl_lock_rename_workdir(workdir, upperdir); 332 if (err) 333 goto out; 334 335 newdentry = ovl_lookup_temp(workdir, dentry); 336 err = PTR_ERR(newdentry); 337 if (IS_ERR(newdentry)) 338 goto out_unlock; 339 340 upper = lookup_one_len(dentry->d_name.name, upperdir, 341 dentry->d_name.len); 342 err = PTR_ERR(upper); 343 if (IS_ERR(upper)) 344 goto out_dput; 345 346 err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); 347 if (err) 348 goto out_dput2; 349 350 if (S_ISDIR(stat->mode)) { 351 err = ovl_set_opaque(newdentry); 352 if (err) 353 goto out_cleanup; 354 355 err = ovl_do_rename(wdir, newdentry, udir, upper, 356 RENAME_EXCHANGE); 357 if (err) 358 goto out_cleanup; 359 360 ovl_cleanup(wdir, upper); 361 } else { 362 err = ovl_do_rename(wdir, newdentry, udir, upper, 0); 363 if (err) 364 goto out_cleanup; 365 } 366 ovl_dentry_version_inc(dentry->d_parent); 367 ovl_dentry_update(dentry, newdentry); 368 ovl_copyattr(newdentry->d_inode, inode); 369 d_instantiate(dentry, inode); 370 newdentry = NULL; 371 out_dput2: 372 dput(upper); 373 out_dput: 374 dput(newdentry); 375 out_unlock: 376 unlock_rename(workdir, upperdir); 377 out: 378 return err; 379 380 out_cleanup: 381 ovl_cleanup(wdir, newdentry); 382 goto out_dput2; 383 } 384 385 static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, 386 const char *link, struct dentry *hardlink) 387 { 388 int err; 389 struct inode *inode; 390 struct kstat stat = { 391 .mode = mode, 392 .rdev = rdev, 393 }; 394 395 err = -ENOMEM; 396 inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata); 397 if (!inode) 398 goto out; 399 400 err = ovl_copy_up(dentry->d_parent); 401 if (err) 402 goto out_iput; 403 404 if (!ovl_dentry_is_opaque(dentry)) { 405 err = ovl_create_upper(dentry, inode, &stat, link, hardlink); 406 } else { 407 const struct cred *old_cred; 408 struct cred *override_cred; 409 410 old_cred = ovl_override_creds(dentry->d_sb); 411 412 err = -ENOMEM; 413 override_cred = prepare_creds(); 414 if (override_cred) { 415 override_cred->fsuid = old_cred->fsuid; 416 override_cred->fsgid = old_cred->fsgid; 417 put_cred(override_creds(override_cred)); 418 put_cred(override_cred); 419 420 err = ovl_create_over_whiteout(dentry, inode, &stat, 421 link, hardlink); 422 } 423 revert_creds(old_cred); 424 } 425 426 if (!err) 427 inode = NULL; 428 out_iput: 429 iput(inode); 430 out: 431 return err; 432 } 433 434 static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, 435 const char *link) 436 { 437 int err; 438 439 err = ovl_want_write(dentry); 440 if (!err) { 441 err = ovl_create_or_link(dentry, mode, rdev, link, NULL); 442 ovl_drop_write(dentry); 443 } 444 445 return err; 446 } 447 448 static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, 449 bool excl) 450 { 451 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); 452 } 453 454 static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 455 { 456 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); 457 } 458 459 static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, 460 dev_t rdev) 461 { 462 /* Don't allow creation of "whiteout" on overlay */ 463 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) 464 return -EPERM; 465 466 return ovl_create_object(dentry, mode, rdev, NULL); 467 } 468 469 static int ovl_symlink(struct inode *dir, struct dentry *dentry, 470 const char *link) 471 { 472 return ovl_create_object(dentry, S_IFLNK, 0, link); 473 } 474 475 static int ovl_link(struct dentry *old, struct inode *newdir, 476 struct dentry *new) 477 { 478 int err; 479 struct dentry *upper; 480 481 err = ovl_want_write(old); 482 if (err) 483 goto out; 484 485 err = ovl_copy_up(old); 486 if (err) 487 goto out_drop_write; 488 489 upper = ovl_dentry_upper(old); 490 err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); 491 492 out_drop_write: 493 ovl_drop_write(old); 494 out: 495 return err; 496 } 497 498 static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) 499 { 500 struct dentry *workdir = ovl_workdir(dentry); 501 struct inode *wdir = workdir->d_inode; 502 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); 503 struct inode *udir = upperdir->d_inode; 504 struct dentry *whiteout; 505 struct dentry *upper; 506 struct dentry *opaquedir = NULL; 507 int err; 508 509 if (WARN_ON(!workdir)) 510 return -EROFS; 511 512 if (is_dir) { 513 if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { 514 opaquedir = ovl_check_empty_and_clear(dentry); 515 err = PTR_ERR(opaquedir); 516 if (IS_ERR(opaquedir)) 517 goto out; 518 } else { 519 LIST_HEAD(list); 520 521 /* 522 * When removing an empty opaque directory, then it 523 * makes no sense to replace it with an exact replica of 524 * itself. But emptiness still needs to be checked. 525 */ 526 err = ovl_check_empty_dir(dentry, &list); 527 ovl_cache_free(&list); 528 if (err) 529 goto out; 530 } 531 } 532 533 err = ovl_lock_rename_workdir(workdir, upperdir); 534 if (err) 535 goto out_dput; 536 537 whiteout = ovl_whiteout(workdir, dentry); 538 err = PTR_ERR(whiteout); 539 if (IS_ERR(whiteout)) 540 goto out_unlock; 541 542 upper = ovl_dentry_upper(dentry); 543 if (!upper) { 544 upper = lookup_one_len(dentry->d_name.name, upperdir, 545 dentry->d_name.len); 546 err = PTR_ERR(upper); 547 if (IS_ERR(upper)) 548 goto kill_whiteout; 549 550 err = ovl_do_rename(wdir, whiteout, udir, upper, 0); 551 dput(upper); 552 if (err) 553 goto kill_whiteout; 554 } else { 555 int flags = 0; 556 557 if (opaquedir) 558 upper = opaquedir; 559 err = -ESTALE; 560 if (upper->d_parent != upperdir) 561 goto kill_whiteout; 562 563 if (is_dir) 564 flags |= RENAME_EXCHANGE; 565 566 err = ovl_do_rename(wdir, whiteout, udir, upper, flags); 567 if (err) 568 goto kill_whiteout; 569 570 if (is_dir) 571 ovl_cleanup(wdir, upper); 572 } 573 ovl_dentry_version_inc(dentry->d_parent); 574 out_d_drop: 575 d_drop(dentry); 576 dput(whiteout); 577 out_unlock: 578 unlock_rename(workdir, upperdir); 579 out_dput: 580 dput(opaquedir); 581 out: 582 return err; 583 584 kill_whiteout: 585 ovl_cleanup(wdir, whiteout); 586 goto out_d_drop; 587 } 588 589 static int ovl_remove_upper(struct dentry *dentry, bool is_dir) 590 { 591 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); 592 struct inode *dir = upperdir->d_inode; 593 struct dentry *upper; 594 int err; 595 596 inode_lock_nested(dir, I_MUTEX_PARENT); 597 upper = lookup_one_len(dentry->d_name.name, upperdir, 598 dentry->d_name.len); 599 err = PTR_ERR(upper); 600 if (IS_ERR(upper)) 601 goto out_unlock; 602 603 err = -ESTALE; 604 if (upper == ovl_dentry_upper(dentry)) { 605 if (is_dir) 606 err = vfs_rmdir(dir, upper); 607 else 608 err = vfs_unlink(dir, upper, NULL); 609 ovl_dentry_version_inc(dentry->d_parent); 610 } 611 dput(upper); 612 613 /* 614 * Keeping this dentry hashed would mean having to release 615 * upperpath/lowerpath, which could only be done if we are the 616 * sole user of this dentry. Too tricky... Just unhash for 617 * now. 618 */ 619 if (!err) 620 d_drop(dentry); 621 out_unlock: 622 inode_unlock(dir); 623 624 return err; 625 } 626 627 static inline int ovl_check_sticky(struct dentry *dentry) 628 { 629 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; 630 struct inode *inode = ovl_dentry_real(dentry)->d_inode; 631 632 if (check_sticky(dir, inode)) 633 return -EPERM; 634 635 return 0; 636 } 637 638 static int ovl_do_remove(struct dentry *dentry, bool is_dir) 639 { 640 enum ovl_path_type type; 641 int err; 642 643 err = ovl_check_sticky(dentry); 644 if (err) 645 goto out; 646 647 err = ovl_want_write(dentry); 648 if (err) 649 goto out; 650 651 err = ovl_copy_up(dentry->d_parent); 652 if (err) 653 goto out_drop_write; 654 655 type = ovl_path_type(dentry); 656 if (OVL_TYPE_PURE_UPPER(type)) { 657 err = ovl_remove_upper(dentry, is_dir); 658 } else { 659 const struct cred *old_cred = ovl_override_creds(dentry->d_sb); 660 661 err = ovl_remove_and_whiteout(dentry, is_dir); 662 663 revert_creds(old_cred); 664 } 665 out_drop_write: 666 ovl_drop_write(dentry); 667 out: 668 return err; 669 } 670 671 static int ovl_unlink(struct inode *dir, struct dentry *dentry) 672 { 673 return ovl_do_remove(dentry, false); 674 } 675 676 static int ovl_rmdir(struct inode *dir, struct dentry *dentry) 677 { 678 return ovl_do_remove(dentry, true); 679 } 680 681 static int ovl_rename2(struct inode *olddir, struct dentry *old, 682 struct inode *newdir, struct dentry *new, 683 unsigned int flags) 684 { 685 int err; 686 enum ovl_path_type old_type; 687 enum ovl_path_type new_type; 688 struct dentry *old_upperdir; 689 struct dentry *new_upperdir; 690 struct dentry *olddentry; 691 struct dentry *newdentry; 692 struct dentry *trap; 693 bool old_opaque; 694 bool new_opaque; 695 bool cleanup_whiteout = false; 696 bool overwrite = !(flags & RENAME_EXCHANGE); 697 bool is_dir = d_is_dir(old); 698 bool new_is_dir = false; 699 struct dentry *opaquedir = NULL; 700 const struct cred *old_cred = NULL; 701 702 err = -EINVAL; 703 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) 704 goto out; 705 706 flags &= ~RENAME_NOREPLACE; 707 708 err = ovl_check_sticky(old); 709 if (err) 710 goto out; 711 712 /* Don't copy up directory trees */ 713 old_type = ovl_path_type(old); 714 err = -EXDEV; 715 if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) 716 goto out; 717 718 if (new->d_inode) { 719 err = ovl_check_sticky(new); 720 if (err) 721 goto out; 722 723 if (d_is_dir(new)) 724 new_is_dir = true; 725 726 new_type = ovl_path_type(new); 727 err = -EXDEV; 728 if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) 729 goto out; 730 731 err = 0; 732 if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { 733 if (ovl_dentry_lower(old)->d_inode == 734 ovl_dentry_lower(new)->d_inode) 735 goto out; 736 } 737 if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { 738 if (ovl_dentry_upper(old)->d_inode == 739 ovl_dentry_upper(new)->d_inode) 740 goto out; 741 } 742 } else { 743 if (ovl_dentry_is_opaque(new)) 744 new_type = __OVL_PATH_UPPER; 745 else 746 new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; 747 } 748 749 err = ovl_want_write(old); 750 if (err) 751 goto out; 752 753 err = ovl_copy_up(old); 754 if (err) 755 goto out_drop_write; 756 757 err = ovl_copy_up(new->d_parent); 758 if (err) 759 goto out_drop_write; 760 if (!overwrite) { 761 err = ovl_copy_up(new); 762 if (err) 763 goto out_drop_write; 764 } 765 766 old_opaque = !OVL_TYPE_PURE_UPPER(old_type); 767 new_opaque = !OVL_TYPE_PURE_UPPER(new_type); 768 769 if (old_opaque || new_opaque) 770 old_cred = ovl_override_creds(old->d_sb); 771 772 if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { 773 opaquedir = ovl_check_empty_and_clear(new); 774 err = PTR_ERR(opaquedir); 775 if (IS_ERR(opaquedir)) { 776 opaquedir = NULL; 777 goto out_revert_creds; 778 } 779 } 780 781 if (overwrite) { 782 if (old_opaque) { 783 if (new->d_inode || !new_opaque) { 784 /* Whiteout source */ 785 flags |= RENAME_WHITEOUT; 786 } else { 787 /* Switch whiteouts */ 788 flags |= RENAME_EXCHANGE; 789 } 790 } else if (is_dir && !new->d_inode && new_opaque) { 791 flags |= RENAME_EXCHANGE; 792 cleanup_whiteout = true; 793 } 794 } 795 796 old_upperdir = ovl_dentry_upper(old->d_parent); 797 new_upperdir = ovl_dentry_upper(new->d_parent); 798 799 trap = lock_rename(new_upperdir, old_upperdir); 800 801 802 olddentry = lookup_one_len(old->d_name.name, old_upperdir, 803 old->d_name.len); 804 err = PTR_ERR(olddentry); 805 if (IS_ERR(olddentry)) 806 goto out_unlock; 807 808 err = -ESTALE; 809 if (olddentry != ovl_dentry_upper(old)) 810 goto out_dput_old; 811 812 newdentry = lookup_one_len(new->d_name.name, new_upperdir, 813 new->d_name.len); 814 err = PTR_ERR(newdentry); 815 if (IS_ERR(newdentry)) 816 goto out_dput_old; 817 818 err = -ESTALE; 819 if (ovl_dentry_upper(new)) { 820 if (opaquedir) { 821 if (newdentry != opaquedir) 822 goto out_dput; 823 } else { 824 if (newdentry != ovl_dentry_upper(new)) 825 goto out_dput; 826 } 827 } else { 828 if (!d_is_negative(newdentry) && 829 (!new_opaque || !ovl_is_whiteout(newdentry))) 830 goto out_dput; 831 } 832 833 if (olddentry == trap) 834 goto out_dput; 835 if (newdentry == trap) 836 goto out_dput; 837 838 if (is_dir && !old_opaque && new_opaque) { 839 err = ovl_set_opaque(olddentry); 840 if (err) 841 goto out_dput; 842 } 843 if (!overwrite && new_is_dir && old_opaque && !new_opaque) { 844 err = ovl_set_opaque(newdentry); 845 if (err) 846 goto out_dput; 847 } 848 849 if (old_opaque || new_opaque) { 850 err = ovl_do_rename(old_upperdir->d_inode, olddentry, 851 new_upperdir->d_inode, newdentry, 852 flags); 853 } else { 854 /* No debug for the plain case */ 855 BUG_ON(flags & ~RENAME_EXCHANGE); 856 err = vfs_rename(old_upperdir->d_inode, olddentry, 857 new_upperdir->d_inode, newdentry, 858 NULL, flags); 859 } 860 861 if (err) { 862 if (is_dir && !old_opaque && new_opaque) 863 ovl_remove_opaque(olddentry); 864 if (!overwrite && new_is_dir && old_opaque && !new_opaque) 865 ovl_remove_opaque(newdentry); 866 goto out_dput; 867 } 868 869 if (is_dir && old_opaque && !new_opaque) 870 ovl_remove_opaque(olddentry); 871 if (!overwrite && new_is_dir && !old_opaque && new_opaque) 872 ovl_remove_opaque(newdentry); 873 874 /* 875 * Old dentry now lives in different location. Dentries in 876 * lowerstack are stale. We cannot drop them here because 877 * access to them is lockless. This could be only pure upper 878 * or opaque directory - numlower is zero. Or upper non-dir 879 * entry - its pureness is tracked by flag opaque. 880 */ 881 if (old_opaque != new_opaque) { 882 ovl_dentry_set_opaque(old, new_opaque); 883 if (!overwrite) 884 ovl_dentry_set_opaque(new, old_opaque); 885 } 886 887 if (cleanup_whiteout) 888 ovl_cleanup(old_upperdir->d_inode, newdentry); 889 890 ovl_dentry_version_inc(old->d_parent); 891 ovl_dentry_version_inc(new->d_parent); 892 893 out_dput: 894 dput(newdentry); 895 out_dput_old: 896 dput(olddentry); 897 out_unlock: 898 unlock_rename(new_upperdir, old_upperdir); 899 out_revert_creds: 900 if (old_opaque || new_opaque) 901 revert_creds(old_cred); 902 out_drop_write: 903 ovl_drop_write(old); 904 out: 905 dput(opaquedir); 906 return err; 907 } 908 909 const struct inode_operations ovl_dir_inode_operations = { 910 .lookup = ovl_lookup, 911 .mkdir = ovl_mkdir, 912 .symlink = ovl_symlink, 913 .unlink = ovl_unlink, 914 .rmdir = ovl_rmdir, 915 .rename2 = ovl_rename2, 916 .link = ovl_link, 917 .setattr = ovl_setattr, 918 .create = ovl_create, 919 .mknod = ovl_mknod, 920 .permission = ovl_permission, 921 .getattr = ovl_dir_getattr, 922 .setxattr = ovl_setxattr, 923 .getxattr = ovl_getxattr, 924 .listxattr = ovl_listxattr, 925 .removexattr = ovl_removexattr, 926 }; 927