Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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); |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 22 | if (d_is_dir(wdentry)) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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 | { |
hujianyang | cead89b | 2014-11-24 18:25:21 +0800 | [diff] [blame] | 121 | return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 122 | } |
| 123 | |
| 124 | static void ovl_remove_opaque(struct dentry *upperdentry) |
| 125 | { |
| 126 | int err; |
| 127 | |
hujianyang | cead89b | 2014-11-24 18:25:21 +0800 | [diff] [blame] | 128 | err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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 | */ |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 155 | if (OVL_TYPE_MERGE(type)) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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 | mutex_lock_nested(&udir->i_mutex, 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 | mutex_unlock(&udir->i_mutex); |
| 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 | err = ovl_lock_rename_workdir(workdir, upperdir); |
| 226 | if (err) |
| 227 | goto out; |
| 228 | |
| 229 | ovl_path_upper(dentry, &upperpath); |
| 230 | err = vfs_getattr(&upperpath, &stat); |
| 231 | if (err) |
| 232 | goto out_unlock; |
| 233 | |
| 234 | err = -ESTALE; |
| 235 | if (!S_ISDIR(stat.mode)) |
| 236 | goto out_unlock; |
| 237 | upper = upperpath.dentry; |
| 238 | if (upper->d_parent->d_inode != udir) |
| 239 | goto out_unlock; |
| 240 | |
| 241 | opaquedir = ovl_lookup_temp(workdir, dentry); |
| 242 | err = PTR_ERR(opaquedir); |
| 243 | if (IS_ERR(opaquedir)) |
| 244 | goto out_unlock; |
| 245 | |
| 246 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); |
| 247 | if (err) |
| 248 | goto out_dput; |
| 249 | |
| 250 | err = ovl_copy_xattr(upper, opaquedir); |
| 251 | if (err) |
| 252 | goto out_cleanup; |
| 253 | |
| 254 | err = ovl_set_opaque(opaquedir); |
| 255 | if (err) |
| 256 | goto out_cleanup; |
| 257 | |
| 258 | mutex_lock(&opaquedir->d_inode->i_mutex); |
| 259 | err = ovl_set_attr(opaquedir, &stat); |
| 260 | mutex_unlock(&opaquedir->d_inode->i_mutex); |
| 261 | if (err) |
| 262 | goto out_cleanup; |
| 263 | |
| 264 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); |
| 265 | if (err) |
| 266 | goto out_cleanup; |
| 267 | |
| 268 | ovl_cleanup_whiteouts(upper, list); |
| 269 | ovl_cleanup(wdir, upper); |
| 270 | unlock_rename(workdir, upperdir); |
| 271 | |
| 272 | /* dentry's upper doesn't match now, get rid of it */ |
| 273 | d_drop(dentry); |
| 274 | |
| 275 | return opaquedir; |
| 276 | |
| 277 | out_cleanup: |
| 278 | ovl_cleanup(wdir, opaquedir); |
| 279 | out_dput: |
| 280 | dput(opaquedir); |
| 281 | out_unlock: |
| 282 | unlock_rename(workdir, upperdir); |
| 283 | out: |
| 284 | return ERR_PTR(err); |
| 285 | } |
| 286 | |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 287 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 288 | { |
| 289 | int err; |
| 290 | struct dentry *ret = NULL; |
| 291 | LIST_HEAD(list); |
| 292 | |
| 293 | err = ovl_check_empty_dir(dentry, &list); |
| 294 | if (err) |
| 295 | ret = ERR_PTR(err); |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 296 | else { |
| 297 | /* |
| 298 | * If no upperdentry then skip clearing whiteouts. |
| 299 | * |
| 300 | * Can race with copy-up, since we don't hold the upperdir |
| 301 | * mutex. Doesn't matter, since copy-up can't create a |
| 302 | * non-empty directory from an empty one. |
| 303 | */ |
| 304 | if (ovl_dentry_upper(dentry)) |
| 305 | ret = ovl_clear_empty(dentry, &list); |
| 306 | } |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 307 | |
| 308 | ovl_cache_free(&list); |
| 309 | |
| 310 | return ret; |
| 311 | } |
| 312 | |
| 313 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, |
| 314 | struct kstat *stat, const char *link, |
| 315 | struct dentry *hardlink) |
| 316 | { |
| 317 | struct dentry *workdir = ovl_workdir(dentry); |
| 318 | struct inode *wdir = workdir->d_inode; |
| 319 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
| 320 | struct inode *udir = upperdir->d_inode; |
| 321 | struct dentry *upper; |
| 322 | struct dentry *newdentry; |
| 323 | int err; |
| 324 | |
| 325 | err = ovl_lock_rename_workdir(workdir, upperdir); |
| 326 | if (err) |
| 327 | goto out; |
| 328 | |
| 329 | newdentry = ovl_lookup_temp(workdir, dentry); |
| 330 | err = PTR_ERR(newdentry); |
| 331 | if (IS_ERR(newdentry)) |
| 332 | goto out_unlock; |
| 333 | |
| 334 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
| 335 | dentry->d_name.len); |
| 336 | err = PTR_ERR(upper); |
| 337 | if (IS_ERR(upper)) |
| 338 | goto out_dput; |
| 339 | |
| 340 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); |
| 341 | if (err) |
| 342 | goto out_dput2; |
| 343 | |
| 344 | if (S_ISDIR(stat->mode)) { |
| 345 | err = ovl_set_opaque(newdentry); |
| 346 | if (err) |
| 347 | goto out_cleanup; |
| 348 | |
| 349 | err = ovl_do_rename(wdir, newdentry, udir, upper, |
| 350 | RENAME_EXCHANGE); |
| 351 | if (err) |
| 352 | goto out_cleanup; |
| 353 | |
| 354 | ovl_cleanup(wdir, upper); |
| 355 | } else { |
| 356 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); |
| 357 | if (err) |
| 358 | goto out_cleanup; |
| 359 | } |
| 360 | ovl_dentry_version_inc(dentry->d_parent); |
| 361 | ovl_dentry_update(dentry, newdentry); |
| 362 | ovl_copyattr(newdentry->d_inode, inode); |
| 363 | d_instantiate(dentry, inode); |
| 364 | newdentry = NULL; |
| 365 | out_dput2: |
| 366 | dput(upper); |
| 367 | out_dput: |
| 368 | dput(newdentry); |
| 369 | out_unlock: |
| 370 | unlock_rename(workdir, upperdir); |
| 371 | out: |
| 372 | return err; |
| 373 | |
| 374 | out_cleanup: |
| 375 | ovl_cleanup(wdir, newdentry); |
| 376 | goto out_dput2; |
| 377 | } |
| 378 | |
| 379 | static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, |
| 380 | const char *link, struct dentry *hardlink) |
| 381 | { |
| 382 | int err; |
| 383 | struct inode *inode; |
| 384 | struct kstat stat = { |
| 385 | .mode = mode, |
| 386 | .rdev = rdev, |
| 387 | }; |
| 388 | |
| 389 | err = -ENOMEM; |
| 390 | inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata); |
| 391 | if (!inode) |
| 392 | goto out; |
| 393 | |
| 394 | err = ovl_copy_up(dentry->d_parent); |
| 395 | if (err) |
| 396 | goto out_iput; |
| 397 | |
| 398 | if (!ovl_dentry_is_opaque(dentry)) { |
| 399 | err = ovl_create_upper(dentry, inode, &stat, link, hardlink); |
| 400 | } else { |
| 401 | const struct cred *old_cred; |
| 402 | struct cred *override_cred; |
| 403 | |
| 404 | err = -ENOMEM; |
| 405 | override_cred = prepare_creds(); |
| 406 | if (!override_cred) |
| 407 | goto out_iput; |
| 408 | |
| 409 | /* |
| 410 | * CAP_SYS_ADMIN for setting opaque xattr |
| 411 | * CAP_DAC_OVERRIDE for create in workdir, rename |
| 412 | * CAP_FOWNER for removing whiteout from sticky dir |
| 413 | */ |
| 414 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); |
| 415 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); |
| 416 | cap_raise(override_cred->cap_effective, CAP_FOWNER); |
| 417 | old_cred = override_creds(override_cred); |
| 418 | |
| 419 | err = ovl_create_over_whiteout(dentry, inode, &stat, link, |
| 420 | hardlink); |
| 421 | |
| 422 | revert_creds(old_cred); |
| 423 | put_cred(override_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 | |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 498 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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 | |
Miklos Szeredi | 263b4a0 | 2014-12-13 00:59:43 +0100 | [diff] [blame] | 509 | if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 510 | opaquedir = ovl_check_empty_and_clear(dentry); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 511 | err = PTR_ERR(opaquedir); |
| 512 | if (IS_ERR(opaquedir)) |
| 513 | goto out; |
| 514 | } |
| 515 | |
| 516 | err = ovl_lock_rename_workdir(workdir, upperdir); |
| 517 | if (err) |
| 518 | goto out_dput; |
| 519 | |
| 520 | whiteout = ovl_whiteout(workdir, dentry); |
| 521 | err = PTR_ERR(whiteout); |
| 522 | if (IS_ERR(whiteout)) |
| 523 | goto out_unlock; |
| 524 | |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 525 | upper = ovl_dentry_upper(dentry); |
| 526 | if (!upper) { |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 527 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 528 | dentry->d_name.len); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 529 | err = PTR_ERR(upper); |
| 530 | if (IS_ERR(upper)) |
| 531 | goto kill_whiteout; |
| 532 | |
| 533 | err = ovl_do_rename(wdir, whiteout, udir, upper, 0); |
| 534 | dput(upper); |
| 535 | if (err) |
| 536 | goto kill_whiteout; |
| 537 | } else { |
| 538 | int flags = 0; |
| 539 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 540 | if (opaquedir) |
| 541 | upper = opaquedir; |
| 542 | err = -ESTALE; |
| 543 | if (upper->d_parent != upperdir) |
| 544 | goto kill_whiteout; |
| 545 | |
| 546 | if (is_dir) |
| 547 | flags |= RENAME_EXCHANGE; |
| 548 | |
| 549 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
| 550 | if (err) |
| 551 | goto kill_whiteout; |
| 552 | |
| 553 | if (is_dir) |
| 554 | ovl_cleanup(wdir, upper); |
| 555 | } |
| 556 | ovl_dentry_version_inc(dentry->d_parent); |
| 557 | out_d_drop: |
| 558 | d_drop(dentry); |
| 559 | dput(whiteout); |
| 560 | out_unlock: |
| 561 | unlock_rename(workdir, upperdir); |
| 562 | out_dput: |
| 563 | dput(opaquedir); |
| 564 | out: |
| 565 | return err; |
| 566 | |
| 567 | kill_whiteout: |
| 568 | ovl_cleanup(wdir, whiteout); |
| 569 | goto out_d_drop; |
| 570 | } |
| 571 | |
| 572 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) |
| 573 | { |
| 574 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
| 575 | struct inode *dir = upperdir->d_inode; |
| 576 | struct dentry *upper = ovl_dentry_upper(dentry); |
| 577 | int err; |
| 578 | |
| 579 | mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); |
| 580 | err = -ESTALE; |
| 581 | if (upper->d_parent == upperdir) { |
| 582 | /* Don't let d_delete() think it can reset d_inode */ |
| 583 | dget(upper); |
| 584 | if (is_dir) |
| 585 | err = vfs_rmdir(dir, upper); |
| 586 | else |
| 587 | err = vfs_unlink(dir, upper, NULL); |
| 588 | dput(upper); |
| 589 | ovl_dentry_version_inc(dentry->d_parent); |
| 590 | } |
| 591 | |
| 592 | /* |
| 593 | * Keeping this dentry hashed would mean having to release |
| 594 | * upperpath/lowerpath, which could only be done if we are the |
| 595 | * sole user of this dentry. Too tricky... Just unhash for |
| 596 | * now. |
| 597 | */ |
| 598 | d_drop(dentry); |
| 599 | mutex_unlock(&dir->i_mutex); |
| 600 | |
| 601 | return err; |
| 602 | } |
| 603 | |
| 604 | static inline int ovl_check_sticky(struct dentry *dentry) |
| 605 | { |
| 606 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; |
| 607 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; |
| 608 | |
| 609 | if (check_sticky(dir, inode)) |
| 610 | return -EPERM; |
| 611 | |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
| 616 | { |
| 617 | enum ovl_path_type type; |
| 618 | int err; |
| 619 | |
| 620 | err = ovl_check_sticky(dentry); |
| 621 | if (err) |
| 622 | goto out; |
| 623 | |
| 624 | err = ovl_want_write(dentry); |
| 625 | if (err) |
| 626 | goto out; |
| 627 | |
| 628 | err = ovl_copy_up(dentry->d_parent); |
| 629 | if (err) |
| 630 | goto out_drop_write; |
| 631 | |
| 632 | type = ovl_path_type(dentry); |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 633 | if (OVL_TYPE_PURE_UPPER(type)) { |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 634 | err = ovl_remove_upper(dentry, is_dir); |
| 635 | } else { |
| 636 | const struct cred *old_cred; |
| 637 | struct cred *override_cred; |
| 638 | |
| 639 | err = -ENOMEM; |
| 640 | override_cred = prepare_creds(); |
| 641 | if (!override_cred) |
| 642 | goto out_drop_write; |
| 643 | |
| 644 | /* |
| 645 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir |
| 646 | * CAP_DAC_OVERRIDE for create in workdir, rename |
| 647 | * CAP_FOWNER for removing whiteout from sticky dir |
| 648 | * CAP_FSETID for chmod of opaque dir |
| 649 | * CAP_CHOWN for chown of opaque dir |
| 650 | */ |
| 651 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); |
| 652 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); |
| 653 | cap_raise(override_cred->cap_effective, CAP_FOWNER); |
| 654 | cap_raise(override_cred->cap_effective, CAP_FSETID); |
| 655 | cap_raise(override_cred->cap_effective, CAP_CHOWN); |
| 656 | old_cred = override_creds(override_cred); |
| 657 | |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 658 | err = ovl_remove_and_whiteout(dentry, is_dir); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 659 | |
| 660 | revert_creds(old_cred); |
| 661 | put_cred(override_cred); |
| 662 | } |
| 663 | out_drop_write: |
| 664 | ovl_drop_write(dentry); |
| 665 | out: |
| 666 | return err; |
| 667 | } |
| 668 | |
| 669 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) |
| 670 | { |
| 671 | return ovl_do_remove(dentry, false); |
| 672 | } |
| 673 | |
| 674 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) |
| 675 | { |
| 676 | return ovl_do_remove(dentry, true); |
| 677 | } |
| 678 | |
| 679 | static int ovl_rename2(struct inode *olddir, struct dentry *old, |
| 680 | struct inode *newdir, struct dentry *new, |
| 681 | unsigned int flags) |
| 682 | { |
| 683 | int err; |
| 684 | enum ovl_path_type old_type; |
| 685 | enum ovl_path_type new_type; |
| 686 | struct dentry *old_upperdir; |
| 687 | struct dentry *new_upperdir; |
| 688 | struct dentry *olddentry; |
| 689 | struct dentry *newdentry; |
| 690 | struct dentry *trap; |
| 691 | bool old_opaque; |
| 692 | bool new_opaque; |
| 693 | bool new_create = false; |
| 694 | bool cleanup_whiteout = false; |
| 695 | bool overwrite = !(flags & RENAME_EXCHANGE); |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 696 | bool is_dir = d_is_dir(old); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 697 | bool new_is_dir = false; |
| 698 | struct dentry *opaquedir = NULL; |
| 699 | const struct cred *old_cred = NULL; |
| 700 | struct cred *override_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; |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 715 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 716 | goto out; |
| 717 | |
| 718 | if (new->d_inode) { |
| 719 | err = ovl_check_sticky(new); |
| 720 | if (err) |
| 721 | goto out; |
| 722 | |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 723 | if (d_is_dir(new)) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 724 | new_is_dir = true; |
| 725 | |
| 726 | new_type = ovl_path_type(new); |
| 727 | err = -EXDEV; |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 728 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 729 | goto out; |
| 730 | |
| 731 | err = 0; |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 732 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 733 | if (ovl_dentry_lower(old)->d_inode == |
| 734 | ovl_dentry_lower(new)->d_inode) |
| 735 | goto out; |
| 736 | } |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 737 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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)) |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 744 | new_type = __OVL_PATH_UPPER; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 745 | else |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 746 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 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 | |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 766 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
| 767 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 768 | |
| 769 | if (old_opaque || new_opaque) { |
| 770 | err = -ENOMEM; |
| 771 | override_cred = prepare_creds(); |
| 772 | if (!override_cred) |
| 773 | goto out_drop_write; |
| 774 | |
| 775 | /* |
| 776 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir |
| 777 | * CAP_DAC_OVERRIDE for create in workdir |
| 778 | * CAP_FOWNER for removing whiteout from sticky dir |
| 779 | * CAP_FSETID for chmod of opaque dir |
| 780 | * CAP_CHOWN for chown of opaque dir |
| 781 | */ |
| 782 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); |
| 783 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); |
| 784 | cap_raise(override_cred->cap_effective, CAP_FOWNER); |
| 785 | cap_raise(override_cred->cap_effective, CAP_FSETID); |
| 786 | cap_raise(override_cred->cap_effective, CAP_CHOWN); |
| 787 | old_cred = override_creds(override_cred); |
| 788 | } |
| 789 | |
Miklos Szeredi | 1afaba1 | 2014-12-13 00:59:42 +0100 | [diff] [blame] | 790 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
Miklos Szeredi | a105d68 | 2014-11-20 16:39:59 +0100 | [diff] [blame] | 791 | opaquedir = ovl_check_empty_and_clear(new); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 792 | err = PTR_ERR(opaquedir); |
| 793 | if (IS_ERR(opaquedir)) { |
| 794 | opaquedir = NULL; |
| 795 | goto out_revert_creds; |
| 796 | } |
| 797 | } |
| 798 | |
| 799 | if (overwrite) { |
| 800 | if (old_opaque) { |
| 801 | if (new->d_inode || !new_opaque) { |
| 802 | /* Whiteout source */ |
| 803 | flags |= RENAME_WHITEOUT; |
| 804 | } else { |
| 805 | /* Switch whiteouts */ |
| 806 | flags |= RENAME_EXCHANGE; |
| 807 | } |
| 808 | } else if (is_dir && !new->d_inode && new_opaque) { |
| 809 | flags |= RENAME_EXCHANGE; |
| 810 | cleanup_whiteout = true; |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | old_upperdir = ovl_dentry_upper(old->d_parent); |
| 815 | new_upperdir = ovl_dentry_upper(new->d_parent); |
| 816 | |
| 817 | trap = lock_rename(new_upperdir, old_upperdir); |
| 818 | |
| 819 | olddentry = ovl_dentry_upper(old); |
| 820 | newdentry = ovl_dentry_upper(new); |
| 821 | if (newdentry) { |
| 822 | if (opaquedir) { |
| 823 | newdentry = opaquedir; |
| 824 | opaquedir = NULL; |
| 825 | } else { |
| 826 | dget(newdentry); |
| 827 | } |
| 828 | } else { |
| 829 | new_create = true; |
| 830 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, |
| 831 | new->d_name.len); |
| 832 | err = PTR_ERR(newdentry); |
| 833 | if (IS_ERR(newdentry)) |
| 834 | goto out_unlock; |
| 835 | } |
| 836 | |
| 837 | err = -ESTALE; |
| 838 | if (olddentry->d_parent != old_upperdir) |
| 839 | goto out_dput; |
| 840 | if (newdentry->d_parent != new_upperdir) |
| 841 | goto out_dput; |
| 842 | if (olddentry == trap) |
| 843 | goto out_dput; |
| 844 | if (newdentry == trap) |
| 845 | goto out_dput; |
| 846 | |
| 847 | if (is_dir && !old_opaque && new_opaque) { |
| 848 | err = ovl_set_opaque(olddentry); |
| 849 | if (err) |
| 850 | goto out_dput; |
| 851 | } |
| 852 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { |
| 853 | err = ovl_set_opaque(newdentry); |
| 854 | if (err) |
| 855 | goto out_dput; |
| 856 | } |
| 857 | |
| 858 | if (old_opaque || new_opaque) { |
| 859 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, |
| 860 | new_upperdir->d_inode, newdentry, |
| 861 | flags); |
| 862 | } else { |
| 863 | /* No debug for the plain case */ |
| 864 | BUG_ON(flags & ~RENAME_EXCHANGE); |
| 865 | err = vfs_rename(old_upperdir->d_inode, olddentry, |
| 866 | new_upperdir->d_inode, newdentry, |
| 867 | NULL, flags); |
| 868 | } |
| 869 | |
| 870 | if (err) { |
| 871 | if (is_dir && !old_opaque && new_opaque) |
| 872 | ovl_remove_opaque(olddentry); |
| 873 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) |
| 874 | ovl_remove_opaque(newdentry); |
| 875 | goto out_dput; |
| 876 | } |
| 877 | |
| 878 | if (is_dir && old_opaque && !new_opaque) |
| 879 | ovl_remove_opaque(olddentry); |
| 880 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) |
| 881 | ovl_remove_opaque(newdentry); |
| 882 | |
| 883 | if (old_opaque != new_opaque) { |
| 884 | ovl_dentry_set_opaque(old, new_opaque); |
| 885 | if (!overwrite) |
| 886 | ovl_dentry_set_opaque(new, old_opaque); |
| 887 | } |
| 888 | |
| 889 | if (cleanup_whiteout) |
| 890 | ovl_cleanup(old_upperdir->d_inode, newdentry); |
| 891 | |
| 892 | ovl_dentry_version_inc(old->d_parent); |
| 893 | ovl_dentry_version_inc(new->d_parent); |
| 894 | |
| 895 | out_dput: |
| 896 | dput(newdentry); |
| 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 | put_cred(override_cred); |
| 903 | } |
| 904 | out_drop_write: |
| 905 | ovl_drop_write(old); |
| 906 | out: |
| 907 | dput(opaquedir); |
| 908 | return err; |
| 909 | } |
| 910 | |
| 911 | const struct inode_operations ovl_dir_inode_operations = { |
| 912 | .lookup = ovl_lookup, |
| 913 | .mkdir = ovl_mkdir, |
| 914 | .symlink = ovl_symlink, |
| 915 | .unlink = ovl_unlink, |
| 916 | .rmdir = ovl_rmdir, |
| 917 | .rename2 = ovl_rename2, |
| 918 | .link = ovl_link, |
| 919 | .setattr = ovl_setattr, |
| 920 | .create = ovl_create, |
| 921 | .mknod = ovl_mknod, |
| 922 | .permission = ovl_permission, |
| 923 | .getattr = ovl_dir_getattr, |
| 924 | .setxattr = ovl_setxattr, |
| 925 | .getxattr = ovl_getxattr, |
| 926 | .listxattr = ovl_listxattr, |
| 927 | .removexattr = ovl_removexattr, |
| 928 | }; |