| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * |
| 4 | * Copyright (C) 2011 Novell Inc. |
| 5 | */ |
| 6 | |
| 7 | #include <uapi/linux/magic.h> |
| 8 | #include <linux/fs.h> |
| 9 | #include <linux/namei.h> |
| 10 | #include <linux/xattr.h> |
| 11 | #include <linux/mount.h> |
| 12 | #include <linux/parser.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/statfs.h> |
| 15 | #include <linux/seq_file.h> |
| 16 | #include <linux/posix_acl_xattr.h> |
| 17 | #include <linux/exportfs.h> |
| 18 | #include <linux/file.h> |
| 19 | #include "overlayfs.h" |
| 20 | |
| 21 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); |
| 22 | MODULE_DESCRIPTION("Overlay filesystem"); |
| 23 | MODULE_LICENSE("GPL"); |
| 24 | |
| 25 | |
| 26 | struct ovl_dir_cache; |
| 27 | |
| 28 | #define OVL_MAX_STACK 500 |
| 29 | |
| 30 | static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); |
| 31 | module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); |
| 32 | MODULE_PARM_DESC(redirect_dir, |
| 33 | "Default to on or off for the redirect_dir feature"); |
| 34 | |
| 35 | static bool ovl_redirect_always_follow = |
| 36 | IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW); |
| 37 | module_param_named(redirect_always_follow, ovl_redirect_always_follow, |
| 38 | bool, 0644); |
| 39 | MODULE_PARM_DESC(redirect_always_follow, |
| 40 | "Follow redirects even if redirect_dir feature is turned off"); |
| 41 | |
| 42 | static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); |
| 43 | module_param_named(index, ovl_index_def, bool, 0644); |
| 44 | MODULE_PARM_DESC(index, |
| 45 | "Default to on or off for the inodes index feature"); |
| 46 | |
| 47 | static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT); |
| 48 | module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); |
| 49 | MODULE_PARM_DESC(nfs_export, |
| 50 | "Default to on or off for the NFS export feature"); |
| 51 | |
| 52 | static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); |
| 53 | module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); |
| 54 | MODULE_PARM_DESC(xino_auto, |
| 55 | "Auto enable xino feature"); |
| 56 | |
| 57 | static void ovl_entry_stack_free(struct ovl_entry *oe) |
| 58 | { |
| 59 | unsigned int i; |
| 60 | |
| 61 | for (i = 0; i < oe->numlower; i++) |
| 62 | dput(oe->lowerstack[i].dentry); |
| 63 | } |
| 64 | |
| 65 | static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); |
| 66 | module_param_named(metacopy, ovl_metacopy_def, bool, 0644); |
| 67 | MODULE_PARM_DESC(metacopy, |
| 68 | "Default to on or off for the metadata only copy up feature"); |
| 69 | |
| 70 | static void ovl_dentry_release(struct dentry *dentry) |
| 71 | { |
| 72 | struct ovl_entry *oe = dentry->d_fsdata; |
| 73 | |
| 74 | if (oe) { |
| 75 | ovl_entry_stack_free(oe); |
| 76 | kfree_rcu(oe, rcu); |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | static struct dentry *ovl_d_real(struct dentry *dentry, |
| 81 | const struct inode *inode) |
| 82 | { |
| 83 | struct dentry *real = NULL, *lower; |
| 84 | |
| 85 | /* It's an overlay file */ |
| 86 | if (inode && d_inode(dentry) == inode) |
| 87 | return dentry; |
| 88 | |
| 89 | if (!d_is_reg(dentry)) { |
| 90 | if (!inode || inode == d_inode(dentry)) |
| 91 | return dentry; |
| 92 | goto bug; |
| 93 | } |
| 94 | |
| 95 | real = ovl_dentry_upper(dentry); |
| 96 | if (real && (inode == d_inode(real))) |
| 97 | return real; |
| 98 | |
| 99 | if (real && !inode && ovl_has_upperdata(d_inode(dentry))) |
| 100 | return real; |
| 101 | |
| 102 | lower = ovl_dentry_lowerdata(dentry); |
| 103 | if (!lower) |
| 104 | goto bug; |
| 105 | real = lower; |
| 106 | |
| 107 | /* Handle recursion */ |
| 108 | real = d_real(real, inode); |
| 109 | |
| 110 | if (!inode || inode == d_inode(real)) |
| 111 | return real; |
| 112 | bug: |
| 113 | WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", |
| 114 | __func__, dentry, inode ? inode->i_sb->s_id : "NULL", |
| 115 | inode ? inode->i_ino : 0, real, |
| 116 | real && d_inode(real) ? d_inode(real)->i_ino : 0); |
| 117 | return dentry; |
| 118 | } |
| 119 | |
| 120 | static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) |
| 121 | { |
| 122 | int ret = 1; |
| 123 | |
| 124 | if (weak) { |
| 125 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) |
| 126 | ret = d->d_op->d_weak_revalidate(d, flags); |
| 127 | } else if (d->d_flags & DCACHE_OP_REVALIDATE) { |
| 128 | ret = d->d_op->d_revalidate(d, flags); |
| 129 | if (!ret) { |
| 130 | if (!(flags & LOOKUP_RCU)) |
| 131 | d_invalidate(d); |
| 132 | ret = -ESTALE; |
| 133 | } |
| 134 | } |
| 135 | return ret; |
| 136 | } |
| 137 | |
| 138 | static int ovl_dentry_revalidate_common(struct dentry *dentry, |
| 139 | unsigned int flags, bool weak) |
| 140 | { |
| 141 | struct ovl_entry *oe = dentry->d_fsdata; |
| 142 | struct dentry *upper; |
| 143 | unsigned int i; |
| 144 | int ret = 1; |
| 145 | |
| 146 | upper = ovl_dentry_upper(dentry); |
| 147 | if (upper) |
| 148 | ret = ovl_revalidate_real(upper, flags, weak); |
| 149 | |
| 150 | for (i = 0; ret > 0 && i < oe->numlower; i++) { |
| 151 | ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, |
| 152 | weak); |
| 153 | } |
| 154 | return ret; |
| 155 | } |
| 156 | |
| 157 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
| 158 | { |
| 159 | return ovl_dentry_revalidate_common(dentry, flags, false); |
| 160 | } |
| 161 | |
| 162 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) |
| 163 | { |
| 164 | return ovl_dentry_revalidate_common(dentry, flags, true); |
| 165 | } |
| 166 | |
| 167 | static const struct dentry_operations ovl_dentry_operations = { |
| 168 | .d_release = ovl_dentry_release, |
| 169 | .d_real = ovl_d_real, |
| 170 | .d_revalidate = ovl_dentry_revalidate, |
| 171 | .d_weak_revalidate = ovl_dentry_weak_revalidate, |
| 172 | }; |
| 173 | |
| 174 | static struct kmem_cache *ovl_inode_cachep; |
| 175 | |
| 176 | static struct inode *ovl_alloc_inode(struct super_block *sb) |
| 177 | { |
| 178 | struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); |
| 179 | |
| 180 | if (!oi) |
| 181 | return NULL; |
| 182 | |
| 183 | oi->cache = NULL; |
| 184 | oi->redirect = NULL; |
| 185 | oi->version = 0; |
| 186 | oi->flags = 0; |
| 187 | oi->__upperdentry = NULL; |
| 188 | oi->lowerpath.dentry = NULL; |
| 189 | oi->lowerpath.layer = NULL; |
| 190 | oi->lowerdata = NULL; |
| 191 | mutex_init(&oi->lock); |
| 192 | |
| 193 | return &oi->vfs_inode; |
| 194 | } |
| 195 | |
| 196 | static void ovl_free_inode(struct inode *inode) |
| 197 | { |
| 198 | struct ovl_inode *oi = OVL_I(inode); |
| 199 | |
| 200 | kfree(oi->redirect); |
| 201 | mutex_destroy(&oi->lock); |
| 202 | kmem_cache_free(ovl_inode_cachep, oi); |
| 203 | } |
| 204 | |
| 205 | static void ovl_destroy_inode(struct inode *inode) |
| 206 | { |
| 207 | struct ovl_inode *oi = OVL_I(inode); |
| 208 | |
| 209 | dput(oi->__upperdentry); |
| 210 | dput(oi->lowerpath.dentry); |
| 211 | if (S_ISDIR(inode->i_mode)) |
| 212 | ovl_dir_cache_free(inode); |
| 213 | else |
| 214 | iput(oi->lowerdata); |
| 215 | } |
| 216 | |
| 217 | static void ovl_free_fs(struct ovl_fs *ofs) |
| 218 | { |
| 219 | struct vfsmount **mounts; |
| 220 | unsigned i; |
| 221 | |
| 222 | iput(ofs->workbasedir_trap); |
| 223 | iput(ofs->indexdir_trap); |
| 224 | iput(ofs->workdir_trap); |
| 225 | dput(ofs->whiteout); |
| 226 | dput(ofs->indexdir); |
| 227 | dput(ofs->workdir); |
| 228 | if (ofs->workdir_locked) |
| 229 | ovl_inuse_unlock(ofs->workbasedir); |
| 230 | dput(ofs->workbasedir); |
| 231 | if (ofs->upperdir_locked) |
| 232 | ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); |
| 233 | |
| 234 | /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ |
| 235 | mounts = (struct vfsmount **) ofs->layers; |
| 236 | for (i = 0; i < ofs->numlayer; i++) { |
| 237 | iput(ofs->layers[i].trap); |
| 238 | mounts[i] = ofs->layers[i].mnt; |
| 239 | } |
| 240 | kern_unmount_array(mounts, ofs->numlayer); |
| 241 | kfree(ofs->layers); |
| 242 | for (i = 0; i < ofs->numfs; i++) |
| 243 | free_anon_bdev(ofs->fs[i].pseudo_dev); |
| 244 | kfree(ofs->fs); |
| 245 | |
| 246 | kfree(ofs->config.lowerdir); |
| 247 | kfree(ofs->config.upperdir); |
| 248 | kfree(ofs->config.workdir); |
| 249 | kfree(ofs->config.redirect_mode); |
| 250 | if (ofs->creator_cred) |
| 251 | put_cred(ofs->creator_cred); |
| 252 | kfree(ofs); |
| 253 | } |
| 254 | |
| 255 | static void ovl_put_super(struct super_block *sb) |
| 256 | { |
| 257 | struct ovl_fs *ofs = sb->s_fs_info; |
| 258 | |
| 259 | ovl_free_fs(ofs); |
| 260 | } |
| 261 | |
| 262 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
| 263 | static int ovl_sync_fs(struct super_block *sb, int wait) |
| 264 | { |
| 265 | struct ovl_fs *ofs = sb->s_fs_info; |
| 266 | struct super_block *upper_sb; |
| 267 | int ret; |
| 268 | |
| 269 | ret = ovl_sync_status(ofs); |
| 270 | /* |
| 271 | * We have to always set the err, because the return value isn't |
| 272 | * checked in syncfs, and instead indirectly return an error via |
| 273 | * the sb's writeback errseq, which VFS inspects after this call. |
| 274 | */ |
| 275 | if (ret < 0) { |
| 276 | errseq_set(&sb->s_wb_err, -EIO); |
| 277 | return -EIO; |
| 278 | } |
| 279 | |
| 280 | if (!ret) |
| 281 | return ret; |
| 282 | |
| 283 | /* |
| 284 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
| 285 | * All the super blocks will be iterated, including upper_sb. |
| 286 | * |
| 287 | * If this is a syncfs(2) call, then we do need to call |
| 288 | * sync_filesystem() on upper_sb, but enough if we do it when being |
| 289 | * called with wait == 1. |
| 290 | */ |
| 291 | if (!wait) |
| 292 | return 0; |
| 293 | |
| 294 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
| 295 | |
| 296 | down_read(&upper_sb->s_umount); |
| 297 | ret = sync_filesystem(upper_sb); |
| 298 | up_read(&upper_sb->s_umount); |
| 299 | |
| 300 | return ret; |
| 301 | } |
| 302 | |
| 303 | /** |
| 304 | * ovl_statfs |
| 305 | * @dentry: The dentry to query |
| 306 | * @buf: The struct kstatfs to fill in with stats |
| 307 | * |
| 308 | * Get the filesystem statistics. As writes always target the upper layer |
| 309 | * filesystem pass the statfs to the upper filesystem (if it exists) |
| 310 | */ |
| 311 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) |
| 312 | { |
| 313 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; |
| 314 | struct dentry *root_dentry = dentry->d_sb->s_root; |
| 315 | struct path path; |
| 316 | int err; |
| 317 | |
| 318 | ovl_path_real(root_dentry, &path); |
| 319 | |
| 320 | err = vfs_statfs(&path, buf); |
| 321 | if (!err) { |
| 322 | buf->f_namelen = ofs->namelen; |
| 323 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
| 324 | } |
| 325 | |
| 326 | return err; |
| 327 | } |
| 328 | |
| 329 | /* Will this overlay be forced to mount/remount ro? */ |
| 330 | static bool ovl_force_readonly(struct ovl_fs *ofs) |
| 331 | { |
| 332 | return (!ovl_upper_mnt(ofs) || !ofs->workdir); |
| 333 | } |
| 334 | |
| 335 | static const char *ovl_redirect_mode_def(void) |
| 336 | { |
| 337 | return ovl_redirect_dir_def ? "on" : "off"; |
| 338 | } |
| 339 | |
| 340 | static const char * const ovl_xino_str[] = { |
| 341 | "off", |
| 342 | "auto", |
| 343 | "on", |
| 344 | }; |
| 345 | |
| 346 | static inline int ovl_xino_def(void) |
| 347 | { |
| 348 | return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; |
| 349 | } |
| 350 | |
| 351 | /** |
| 352 | * ovl_show_options |
| 353 | * @m: the seq_file handle |
| 354 | * @dentry: The dentry to query |
| 355 | * |
| 356 | * Prints the mount options for a given superblock. |
| 357 | * Returns zero; does not fail. |
| 358 | */ |
| 359 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) |
| 360 | { |
| 361 | struct super_block *sb = dentry->d_sb; |
| 362 | struct ovl_fs *ofs = sb->s_fs_info; |
| 363 | |
| 364 | seq_show_option(m, "lowerdir", ofs->config.lowerdir); |
| 365 | if (ofs->config.upperdir) { |
| 366 | seq_show_option(m, "upperdir", ofs->config.upperdir); |
| 367 | seq_show_option(m, "workdir", ofs->config.workdir); |
| 368 | } |
| 369 | if (ofs->config.default_permissions) |
| 370 | seq_puts(m, ",default_permissions"); |
| 371 | if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) |
| 372 | seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); |
| 373 | if (ofs->config.index != ovl_index_def) |
| 374 | seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); |
| 375 | if (!ofs->config.uuid) |
| 376 | seq_puts(m, ",uuid=off"); |
| 377 | if (ofs->config.nfs_export != ovl_nfs_export_def) |
| 378 | seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? |
| 379 | "on" : "off"); |
| 380 | if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) |
| 381 | seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); |
| 382 | if (ofs->config.metacopy != ovl_metacopy_def) |
| 383 | seq_printf(m, ",metacopy=%s", |
| 384 | ofs->config.metacopy ? "on" : "off"); |
| 385 | if (ofs->config.ovl_volatile) |
| 386 | seq_puts(m, ",volatile"); |
| 387 | if (ofs->config.userxattr) |
| 388 | seq_puts(m, ",userxattr"); |
| 389 | return 0; |
| 390 | } |
| 391 | |
| 392 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
| 393 | { |
| 394 | struct ovl_fs *ofs = sb->s_fs_info; |
| 395 | struct super_block *upper_sb; |
| 396 | int ret = 0; |
| 397 | |
| 398 | if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) |
| 399 | return -EROFS; |
| 400 | |
| 401 | if (*flags & SB_RDONLY && !sb_rdonly(sb)) { |
| 402 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
| 403 | if (ovl_should_sync(ofs)) { |
| 404 | down_read(&upper_sb->s_umount); |
| 405 | ret = sync_filesystem(upper_sb); |
| 406 | up_read(&upper_sb->s_umount); |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | return ret; |
| 411 | } |
| 412 | |
| 413 | static const struct super_operations ovl_super_operations = { |
| 414 | .alloc_inode = ovl_alloc_inode, |
| 415 | .free_inode = ovl_free_inode, |
| 416 | .destroy_inode = ovl_destroy_inode, |
| 417 | .drop_inode = generic_delete_inode, |
| 418 | .put_super = ovl_put_super, |
| 419 | .sync_fs = ovl_sync_fs, |
| 420 | .statfs = ovl_statfs, |
| 421 | .show_options = ovl_show_options, |
| 422 | .remount_fs = ovl_remount, |
| 423 | }; |
| 424 | |
| 425 | enum { |
| 426 | OPT_LOWERDIR, |
| 427 | OPT_UPPERDIR, |
| 428 | OPT_WORKDIR, |
| 429 | OPT_DEFAULT_PERMISSIONS, |
| 430 | OPT_REDIRECT_DIR, |
| 431 | OPT_INDEX_ON, |
| 432 | OPT_INDEX_OFF, |
| 433 | OPT_UUID_ON, |
| 434 | OPT_UUID_OFF, |
| 435 | OPT_NFS_EXPORT_ON, |
| 436 | OPT_USERXATTR, |
| 437 | OPT_NFS_EXPORT_OFF, |
| 438 | OPT_XINO_ON, |
| 439 | OPT_XINO_OFF, |
| 440 | OPT_XINO_AUTO, |
| 441 | OPT_METACOPY_ON, |
| 442 | OPT_METACOPY_OFF, |
| 443 | OPT_VOLATILE, |
| 444 | OPT_ERR, |
| 445 | }; |
| 446 | |
| 447 | static const match_table_t ovl_tokens = { |
| 448 | {OPT_LOWERDIR, "lowerdir=%s"}, |
| 449 | {OPT_UPPERDIR, "upperdir=%s"}, |
| 450 | {OPT_WORKDIR, "workdir=%s"}, |
| 451 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
| 452 | {OPT_REDIRECT_DIR, "redirect_dir=%s"}, |
| 453 | {OPT_INDEX_ON, "index=on"}, |
| 454 | {OPT_INDEX_OFF, "index=off"}, |
| 455 | {OPT_USERXATTR, "userxattr"}, |
| 456 | {OPT_UUID_ON, "uuid=on"}, |
| 457 | {OPT_UUID_OFF, "uuid=off"}, |
| 458 | {OPT_NFS_EXPORT_ON, "nfs_export=on"}, |
| 459 | {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, |
| 460 | {OPT_XINO_ON, "xino=on"}, |
| 461 | {OPT_XINO_OFF, "xino=off"}, |
| 462 | {OPT_XINO_AUTO, "xino=auto"}, |
| 463 | {OPT_METACOPY_ON, "metacopy=on"}, |
| 464 | {OPT_METACOPY_OFF, "metacopy=off"}, |
| 465 | {OPT_VOLATILE, "volatile"}, |
| 466 | {OPT_ERR, NULL} |
| 467 | }; |
| 468 | |
| 469 | static char *ovl_next_opt(char **s) |
| 470 | { |
| 471 | char *sbegin = *s; |
| 472 | char *p; |
| 473 | |
| 474 | if (sbegin == NULL) |
| 475 | return NULL; |
| 476 | |
| 477 | for (p = sbegin; *p; p++) { |
| 478 | if (*p == '\\') { |
| 479 | p++; |
| 480 | if (!*p) |
| 481 | break; |
| 482 | } else if (*p == ',') { |
| 483 | *p = '\0'; |
| 484 | *s = p + 1; |
| 485 | return sbegin; |
| 486 | } |
| 487 | } |
| 488 | *s = NULL; |
| 489 | return sbegin; |
| 490 | } |
| 491 | |
| 492 | static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) |
| 493 | { |
| 494 | if (strcmp(mode, "on") == 0) { |
| 495 | config->redirect_dir = true; |
| 496 | /* |
| 497 | * Does not make sense to have redirect creation without |
| 498 | * redirect following. |
| 499 | */ |
| 500 | config->redirect_follow = true; |
| 501 | } else if (strcmp(mode, "follow") == 0) { |
| 502 | config->redirect_follow = true; |
| 503 | } else if (strcmp(mode, "off") == 0) { |
| 504 | if (ovl_redirect_always_follow) |
| 505 | config->redirect_follow = true; |
| 506 | } else if (strcmp(mode, "nofollow") != 0) { |
| 507 | pr_err("bad mount option \"redirect_dir=%s\"\n", |
| 508 | mode); |
| 509 | return -EINVAL; |
| 510 | } |
| 511 | |
| 512 | return 0; |
| 513 | } |
| 514 | |
| 515 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
| 516 | { |
| 517 | char *p; |
| 518 | int err; |
| 519 | bool metacopy_opt = false, redirect_opt = false; |
| 520 | bool nfs_export_opt = false, index_opt = false; |
| 521 | |
| 522 | config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); |
| 523 | if (!config->redirect_mode) |
| 524 | return -ENOMEM; |
| 525 | |
| 526 | while ((p = ovl_next_opt(&opt)) != NULL) { |
| 527 | int token; |
| 528 | substring_t args[MAX_OPT_ARGS]; |
| 529 | |
| 530 | if (!*p) |
| 531 | continue; |
| 532 | |
| 533 | token = match_token(p, ovl_tokens, args); |
| 534 | switch (token) { |
| 535 | case OPT_UPPERDIR: |
| 536 | kfree(config->upperdir); |
| 537 | config->upperdir = match_strdup(&args[0]); |
| 538 | if (!config->upperdir) |
| 539 | return -ENOMEM; |
| 540 | break; |
| 541 | |
| 542 | case OPT_LOWERDIR: |
| 543 | kfree(config->lowerdir); |
| 544 | config->lowerdir = match_strdup(&args[0]); |
| 545 | if (!config->lowerdir) |
| 546 | return -ENOMEM; |
| 547 | break; |
| 548 | |
| 549 | case OPT_WORKDIR: |
| 550 | kfree(config->workdir); |
| 551 | config->workdir = match_strdup(&args[0]); |
| 552 | if (!config->workdir) |
| 553 | return -ENOMEM; |
| 554 | break; |
| 555 | |
| 556 | case OPT_DEFAULT_PERMISSIONS: |
| 557 | config->default_permissions = true; |
| 558 | break; |
| 559 | |
| 560 | case OPT_REDIRECT_DIR: |
| 561 | kfree(config->redirect_mode); |
| 562 | config->redirect_mode = match_strdup(&args[0]); |
| 563 | if (!config->redirect_mode) |
| 564 | return -ENOMEM; |
| 565 | redirect_opt = true; |
| 566 | break; |
| 567 | |
| 568 | case OPT_INDEX_ON: |
| 569 | config->index = true; |
| 570 | index_opt = true; |
| 571 | break; |
| 572 | |
| 573 | case OPT_INDEX_OFF: |
| 574 | config->index = false; |
| 575 | index_opt = true; |
| 576 | break; |
| 577 | |
| 578 | case OPT_UUID_ON: |
| 579 | config->uuid = true; |
| 580 | break; |
| 581 | |
| 582 | case OPT_UUID_OFF: |
| 583 | config->uuid = false; |
| 584 | break; |
| 585 | |
| 586 | case OPT_NFS_EXPORT_ON: |
| 587 | config->nfs_export = true; |
| 588 | nfs_export_opt = true; |
| 589 | break; |
| 590 | |
| 591 | case OPT_NFS_EXPORT_OFF: |
| 592 | config->nfs_export = false; |
| 593 | nfs_export_opt = true; |
| 594 | break; |
| 595 | |
| 596 | case OPT_XINO_ON: |
| 597 | config->xino = OVL_XINO_ON; |
| 598 | break; |
| 599 | |
| 600 | case OPT_XINO_OFF: |
| 601 | config->xino = OVL_XINO_OFF; |
| 602 | break; |
| 603 | |
| 604 | case OPT_XINO_AUTO: |
| 605 | config->xino = OVL_XINO_AUTO; |
| 606 | break; |
| 607 | |
| 608 | case OPT_METACOPY_ON: |
| 609 | config->metacopy = true; |
| 610 | metacopy_opt = true; |
| 611 | break; |
| 612 | |
| 613 | case OPT_METACOPY_OFF: |
| 614 | config->metacopy = false; |
| 615 | metacopy_opt = true; |
| 616 | break; |
| 617 | |
| 618 | case OPT_VOLATILE: |
| 619 | config->ovl_volatile = true; |
| 620 | break; |
| 621 | |
| 622 | case OPT_USERXATTR: |
| 623 | config->userxattr = true; |
| 624 | break; |
| 625 | |
| 626 | default: |
| 627 | pr_err("unrecognized mount option \"%s\" or missing value\n", |
| 628 | p); |
| 629 | return -EINVAL; |
| 630 | } |
| 631 | } |
| 632 | |
| 633 | /* Workdir/index are useless in non-upper mount */ |
| 634 | if (!config->upperdir) { |
| 635 | if (config->workdir) { |
| 636 | pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", |
| 637 | config->workdir); |
| 638 | kfree(config->workdir); |
| 639 | config->workdir = NULL; |
| 640 | } |
| 641 | if (config->index && index_opt) { |
| 642 | pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); |
| 643 | index_opt = false; |
| 644 | } |
| 645 | config->index = false; |
| 646 | } |
| 647 | |
| 648 | if (!config->upperdir && config->ovl_volatile) { |
| 649 | pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); |
| 650 | config->ovl_volatile = false; |
| 651 | } |
| 652 | |
| 653 | err = ovl_parse_redirect_mode(config, config->redirect_mode); |
| 654 | if (err) |
| 655 | return err; |
| 656 | |
| 657 | /* |
| 658 | * This is to make the logic below simpler. It doesn't make any other |
| 659 | * difference, since config->redirect_dir is only used for upper. |
| 660 | */ |
| 661 | if (!config->upperdir && config->redirect_follow) |
| 662 | config->redirect_dir = true; |
| 663 | |
| 664 | /* Resolve metacopy -> redirect_dir dependency */ |
| 665 | if (config->metacopy && !config->redirect_dir) { |
| 666 | if (metacopy_opt && redirect_opt) { |
| 667 | pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", |
| 668 | config->redirect_mode); |
| 669 | return -EINVAL; |
| 670 | } |
| 671 | if (redirect_opt) { |
| 672 | /* |
| 673 | * There was an explicit redirect_dir=... that resulted |
| 674 | * in this conflict. |
| 675 | */ |
| 676 | pr_info("disabling metacopy due to redirect_dir=%s\n", |
| 677 | config->redirect_mode); |
| 678 | config->metacopy = false; |
| 679 | } else { |
| 680 | /* Automatically enable redirect otherwise. */ |
| 681 | config->redirect_follow = config->redirect_dir = true; |
| 682 | } |
| 683 | } |
| 684 | |
| 685 | /* Resolve nfs_export -> index dependency */ |
| 686 | if (config->nfs_export && !config->index) { |
| 687 | if (!config->upperdir && config->redirect_follow) { |
| 688 | pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); |
| 689 | config->nfs_export = false; |
| 690 | } else if (nfs_export_opt && index_opt) { |
| 691 | pr_err("conflicting options: nfs_export=on,index=off\n"); |
| 692 | return -EINVAL; |
| 693 | } else if (index_opt) { |
| 694 | /* |
| 695 | * There was an explicit index=off that resulted |
| 696 | * in this conflict. |
| 697 | */ |
| 698 | pr_info("disabling nfs_export due to index=off\n"); |
| 699 | config->nfs_export = false; |
| 700 | } else { |
| 701 | /* Automatically enable index otherwise. */ |
| 702 | config->index = true; |
| 703 | } |
| 704 | } |
| 705 | |
| 706 | /* Resolve nfs_export -> !metacopy dependency */ |
| 707 | if (config->nfs_export && config->metacopy) { |
| 708 | if (nfs_export_opt && metacopy_opt) { |
| 709 | pr_err("conflicting options: nfs_export=on,metacopy=on\n"); |
| 710 | return -EINVAL; |
| 711 | } |
| 712 | if (metacopy_opt) { |
| 713 | /* |
| 714 | * There was an explicit metacopy=on that resulted |
| 715 | * in this conflict. |
| 716 | */ |
| 717 | pr_info("disabling nfs_export due to metacopy=on\n"); |
| 718 | config->nfs_export = false; |
| 719 | } else { |
| 720 | /* |
| 721 | * There was an explicit nfs_export=on that resulted |
| 722 | * in this conflict. |
| 723 | */ |
| 724 | pr_info("disabling metacopy due to nfs_export=on\n"); |
| 725 | config->metacopy = false; |
| 726 | } |
| 727 | } |
| 728 | |
| 729 | |
| 730 | /* Resolve userxattr -> !redirect && !metacopy dependency */ |
| 731 | if (config->userxattr) { |
| 732 | if (config->redirect_follow && redirect_opt) { |
| 733 | pr_err("conflicting options: userxattr,redirect_dir=%s\n", |
| 734 | config->redirect_mode); |
| 735 | return -EINVAL; |
| 736 | } |
| 737 | if (config->metacopy && metacopy_opt) { |
| 738 | pr_err("conflicting options: userxattr,metacopy=on\n"); |
| 739 | return -EINVAL; |
| 740 | } |
| 741 | /* |
| 742 | * Silently disable default setting of redirect and metacopy. |
| 743 | * This shall be the default in the future as well: these |
| 744 | * options must be explicitly enabled if used together with |
| 745 | * userxattr. |
| 746 | */ |
| 747 | config->redirect_dir = config->redirect_follow = false; |
| 748 | config->metacopy = false; |
| 749 | } |
| 750 | |
| 751 | return 0; |
| 752 | } |
| 753 | |
| 754 | #define OVL_WORKDIR_NAME "work" |
| 755 | #define OVL_INDEXDIR_NAME "index" |
| 756 | |
| 757 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
| 758 | const char *name, bool persist) |
| 759 | { |
| 760 | struct inode *dir = ofs->workbasedir->d_inode; |
| 761 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
| 762 | struct dentry *work; |
| 763 | int err; |
| 764 | bool retried = false; |
| 765 | |
| 766 | inode_lock_nested(dir, I_MUTEX_PARENT); |
| 767 | retry: |
| 768 | work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); |
| 769 | |
| 770 | if (!IS_ERR(work)) { |
| 771 | struct iattr attr = { |
| 772 | .ia_valid = ATTR_MODE, |
| 773 | .ia_mode = S_IFDIR | 0, |
| 774 | }; |
| 775 | |
| 776 | if (work->d_inode) { |
| 777 | err = -EEXIST; |
| 778 | if (retried) |
| 779 | goto out_dput; |
| 780 | |
| 781 | if (persist) |
| 782 | goto out_unlock; |
| 783 | |
| 784 | retried = true; |
| 785 | err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); |
| 786 | dput(work); |
| 787 | if (err == -EINVAL) { |
| 788 | work = ERR_PTR(err); |
| 789 | goto out_unlock; |
| 790 | } |
| 791 | goto retry; |
| 792 | } |
| 793 | |
| 794 | err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); |
| 795 | if (err) |
| 796 | goto out_dput; |
| 797 | |
| 798 | /* Weird filesystem returning with hashed negative (kernfs)? */ |
| 799 | err = -EINVAL; |
| 800 | if (d_really_is_negative(work)) |
| 801 | goto out_dput; |
| 802 | |
| 803 | /* |
| 804 | * Try to remove POSIX ACL xattrs from workdir. We are good if: |
| 805 | * |
| 806 | * a) success (there was a POSIX ACL xattr and was removed) |
| 807 | * b) -ENODATA (there was no POSIX ACL xattr) |
| 808 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) |
| 809 | * |
| 810 | * There are various other error values that could effectively |
| 811 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned |
| 812 | * if the xattr name is too long), but the set of filesystems |
| 813 | * allowed as upper are limited to "normal" ones, where checking |
| 814 | * for the above two errors is sufficient. |
| 815 | */ |
| 816 | err = ovl_do_removexattr(ofs, work, |
| 817 | XATTR_NAME_POSIX_ACL_DEFAULT); |
| 818 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
| 819 | goto out_dput; |
| 820 | |
| 821 | err = ovl_do_removexattr(ofs, work, |
| 822 | XATTR_NAME_POSIX_ACL_ACCESS); |
| 823 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
| 824 | goto out_dput; |
| 825 | |
| 826 | /* Clear any inherited mode bits */ |
| 827 | inode_lock(work->d_inode); |
| 828 | err = ovl_do_notify_change(ofs, work, &attr); |
| 829 | inode_unlock(work->d_inode); |
| 830 | if (err) |
| 831 | goto out_dput; |
| 832 | } else { |
| 833 | err = PTR_ERR(work); |
| 834 | goto out_err; |
| 835 | } |
| 836 | out_unlock: |
| 837 | inode_unlock(dir); |
| 838 | return work; |
| 839 | |
| 840 | out_dput: |
| 841 | dput(work); |
| 842 | out_err: |
| 843 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
| 844 | ofs->config.workdir, name, -err); |
| 845 | work = NULL; |
| 846 | goto out_unlock; |
| 847 | } |
| 848 | |
| 849 | static void ovl_unescape(char *s) |
| 850 | { |
| 851 | char *d = s; |
| 852 | |
| 853 | for (;; s++, d++) { |
| 854 | if (*s == '\\') |
| 855 | s++; |
| 856 | *d = *s; |
| 857 | if (!*s) |
| 858 | break; |
| 859 | } |
| 860 | } |
| 861 | |
| 862 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
| 863 | { |
| 864 | int err = -EINVAL; |
| 865 | |
| 866 | if (!*name) { |
| 867 | pr_err("empty lowerdir\n"); |
| 868 | goto out; |
| 869 | } |
| 870 | err = kern_path(name, LOOKUP_FOLLOW, path); |
| 871 | if (err) { |
| 872 | pr_err("failed to resolve '%s': %i\n", name, err); |
| 873 | goto out; |
| 874 | } |
| 875 | err = -EINVAL; |
| 876 | if (ovl_dentry_weird(path->dentry)) { |
| 877 | pr_err("filesystem on '%s' not supported\n", name); |
| 878 | goto out_put; |
| 879 | } |
| 880 | if (!d_is_dir(path->dentry)) { |
| 881 | pr_err("'%s' not a directory\n", name); |
| 882 | goto out_put; |
| 883 | } |
| 884 | return 0; |
| 885 | |
| 886 | out_put: |
| 887 | path_put_init(path); |
| 888 | out: |
| 889 | return err; |
| 890 | } |
| 891 | |
| 892 | static int ovl_mount_dir(const char *name, struct path *path) |
| 893 | { |
| 894 | int err = -ENOMEM; |
| 895 | char *tmp = kstrdup(name, GFP_KERNEL); |
| 896 | |
| 897 | if (tmp) { |
| 898 | ovl_unescape(tmp); |
| 899 | err = ovl_mount_dir_noesc(tmp, path); |
| 900 | |
| 901 | if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { |
| 902 | pr_err("filesystem on '%s' not supported as upperdir\n", |
| 903 | tmp); |
| 904 | path_put_init(path); |
| 905 | err = -EINVAL; |
| 906 | } |
| 907 | kfree(tmp); |
| 908 | } |
| 909 | return err; |
| 910 | } |
| 911 | |
| 912 | static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, |
| 913 | const char *name) |
| 914 | { |
| 915 | struct kstatfs statfs; |
| 916 | int err = vfs_statfs(path, &statfs); |
| 917 | |
| 918 | if (err) |
| 919 | pr_err("statfs failed on '%s'\n", name); |
| 920 | else |
| 921 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); |
| 922 | |
| 923 | return err; |
| 924 | } |
| 925 | |
| 926 | static int ovl_lower_dir(const char *name, struct path *path, |
| 927 | struct ovl_fs *ofs, int *stack_depth) |
| 928 | { |
| 929 | int fh_type; |
| 930 | int err; |
| 931 | |
| 932 | err = ovl_mount_dir_noesc(name, path); |
| 933 | if (err) |
| 934 | return err; |
| 935 | |
| 936 | err = ovl_check_namelen(path, ofs, name); |
| 937 | if (err) |
| 938 | return err; |
| 939 | |
| 940 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
| 941 | |
| 942 | /* |
| 943 | * The inodes index feature and NFS export need to encode and decode |
| 944 | * file handles, so they require that all layers support them. |
| 945 | */ |
| 946 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
| 947 | if ((ofs->config.nfs_export || |
| 948 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
| 949 | ofs->config.index = false; |
| 950 | ofs->config.nfs_export = false; |
| 951 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
| 952 | name); |
| 953 | } |
| 954 | /* |
| 955 | * Decoding origin file handle is required for persistent st_ino. |
| 956 | * Without persistent st_ino, xino=auto falls back to xino=off. |
| 957 | */ |
| 958 | if (ofs->config.xino == OVL_XINO_AUTO && |
| 959 | ofs->config.upperdir && !fh_type) { |
| 960 | ofs->config.xino = OVL_XINO_OFF; |
| 961 | pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", |
| 962 | name); |
| 963 | } |
| 964 | |
| 965 | /* Check if lower fs has 32bit inode numbers */ |
| 966 | if (fh_type != FILEID_INO32_GEN) |
| 967 | ofs->xino_mode = -1; |
| 968 | |
| 969 | return 0; |
| 970 | } |
| 971 | |
| 972 | /* Workdir should not be subdir of upperdir and vice versa */ |
| 973 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) |
| 974 | { |
| 975 | bool ok = false; |
| 976 | |
| 977 | if (workdir != upperdir) { |
| 978 | ok = (lock_rename(workdir, upperdir) == NULL); |
| 979 | unlock_rename(workdir, upperdir); |
| 980 | } |
| 981 | return ok; |
| 982 | } |
| 983 | |
| 984 | static unsigned int ovl_split_lowerdirs(char *str) |
| 985 | { |
| 986 | unsigned int ctr = 1; |
| 987 | char *s, *d; |
| 988 | |
| 989 | for (s = d = str;; s++, d++) { |
| 990 | if (*s == '\\') { |
| 991 | s++; |
| 992 | } else if (*s == ':') { |
| 993 | *d = '\0'; |
| 994 | ctr++; |
| 995 | continue; |
| 996 | } |
| 997 | *d = *s; |
| 998 | if (!*s) |
| 999 | break; |
| 1000 | } |
| 1001 | return ctr; |
| 1002 | } |
| 1003 | |
| 1004 | static int __maybe_unused |
| 1005 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, |
| 1006 | struct dentry *dentry, struct inode *inode, |
| 1007 | const char *name, void *buffer, size_t size) |
| 1008 | { |
| 1009 | return ovl_xattr_get(dentry, inode, handler->name, buffer, size); |
| 1010 | } |
| 1011 | |
| 1012 | static int __maybe_unused |
| 1013 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, |
| 1014 | struct user_namespace *mnt_userns, |
| 1015 | struct dentry *dentry, struct inode *inode, |
| 1016 | const char *name, const void *value, |
| 1017 | size_t size, int flags) |
| 1018 | { |
| 1019 | struct dentry *workdir = ovl_workdir(dentry); |
| 1020 | struct inode *realinode = ovl_inode_real(inode); |
| 1021 | struct posix_acl *acl = NULL; |
| 1022 | int err; |
| 1023 | |
| 1024 | /* Check that everything is OK before copy-up */ |
| 1025 | if (value) { |
| 1026 | /* The above comment can be understood in two ways: |
| 1027 | * |
| 1028 | * 1. We just want to check whether the basic POSIX ACL format |
| 1029 | * is ok. For example, if the header is correct and the size |
| 1030 | * is sane. |
| 1031 | * 2. We want to know whether the ACL_{GROUP,USER} entries can |
| 1032 | * be mapped according to the underlying filesystem. |
| 1033 | * |
| 1034 | * Currently, we only check 1. If we wanted to check 2. we |
| 1035 | * would need to pass the mnt_userns and the fs_userns of the |
| 1036 | * underlying filesystem. But frankly, I think checking 1. is |
| 1037 | * enough to start the copy-up. |
| 1038 | */ |
| 1039 | acl = vfs_set_acl_prepare(&init_user_ns, &init_user_ns, value, size); |
| 1040 | if (IS_ERR(acl)) |
| 1041 | return PTR_ERR(acl); |
| 1042 | } |
| 1043 | err = -EOPNOTSUPP; |
| 1044 | if (!IS_POSIXACL(d_inode(workdir))) |
| 1045 | goto out_acl_release; |
| 1046 | if (!realinode->i_op->set_acl) |
| 1047 | goto out_acl_release; |
| 1048 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { |
| 1049 | err = acl ? -EACCES : 0; |
| 1050 | goto out_acl_release; |
| 1051 | } |
| 1052 | err = -EPERM; |
| 1053 | if (!inode_owner_or_capable(&init_user_ns, inode)) |
| 1054 | goto out_acl_release; |
| 1055 | |
| 1056 | posix_acl_release(acl); |
| 1057 | |
| 1058 | /* |
| 1059 | * Check if sgid bit needs to be cleared (actual setacl operation will |
| 1060 | * be done with mounter's capabilities and so that won't do it for us). |
| 1061 | */ |
| 1062 | if (unlikely(inode->i_mode & S_ISGID) && |
| 1063 | handler->flags == ACL_TYPE_ACCESS && |
| 1064 | !in_group_p(inode->i_gid) && |
| 1065 | !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) { |
| 1066 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; |
| 1067 | |
| 1068 | err = ovl_setattr(&init_user_ns, dentry, &iattr); |
| 1069 | if (err) |
| 1070 | return err; |
| 1071 | } |
| 1072 | |
| 1073 | err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); |
| 1074 | return err; |
| 1075 | |
| 1076 | out_acl_release: |
| 1077 | posix_acl_release(acl); |
| 1078 | return err; |
| 1079 | } |
| 1080 | |
| 1081 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
| 1082 | struct dentry *dentry, struct inode *inode, |
| 1083 | const char *name, void *buffer, size_t size) |
| 1084 | { |
| 1085 | return -EOPNOTSUPP; |
| 1086 | } |
| 1087 | |
| 1088 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
| 1089 | struct user_namespace *mnt_userns, |
| 1090 | struct dentry *dentry, struct inode *inode, |
| 1091 | const char *name, const void *value, |
| 1092 | size_t size, int flags) |
| 1093 | { |
| 1094 | return -EOPNOTSUPP; |
| 1095 | } |
| 1096 | |
| 1097 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
| 1098 | struct dentry *dentry, struct inode *inode, |
| 1099 | const char *name, void *buffer, size_t size) |
| 1100 | { |
| 1101 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
| 1102 | } |
| 1103 | |
| 1104 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
| 1105 | struct user_namespace *mnt_userns, |
| 1106 | struct dentry *dentry, struct inode *inode, |
| 1107 | const char *name, const void *value, |
| 1108 | size_t size, int flags) |
| 1109 | { |
| 1110 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
| 1111 | } |
| 1112 | |
| 1113 | static const struct xattr_handler __maybe_unused |
| 1114 | ovl_posix_acl_access_xattr_handler = { |
| 1115 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
| 1116 | .flags = ACL_TYPE_ACCESS, |
| 1117 | .get = ovl_posix_acl_xattr_get, |
| 1118 | .set = ovl_posix_acl_xattr_set, |
| 1119 | }; |
| 1120 | |
| 1121 | static const struct xattr_handler __maybe_unused |
| 1122 | ovl_posix_acl_default_xattr_handler = { |
| 1123 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
| 1124 | .flags = ACL_TYPE_DEFAULT, |
| 1125 | .get = ovl_posix_acl_xattr_get, |
| 1126 | .set = ovl_posix_acl_xattr_set, |
| 1127 | }; |
| 1128 | |
| 1129 | static const struct xattr_handler ovl_own_trusted_xattr_handler = { |
| 1130 | .prefix = OVL_XATTR_TRUSTED_PREFIX, |
| 1131 | .get = ovl_own_xattr_get, |
| 1132 | .set = ovl_own_xattr_set, |
| 1133 | }; |
| 1134 | |
| 1135 | static const struct xattr_handler ovl_own_user_xattr_handler = { |
| 1136 | .prefix = OVL_XATTR_USER_PREFIX, |
| 1137 | .get = ovl_own_xattr_get, |
| 1138 | .set = ovl_own_xattr_set, |
| 1139 | }; |
| 1140 | |
| 1141 | static const struct xattr_handler ovl_other_xattr_handler = { |
| 1142 | .prefix = "", /* catch all */ |
| 1143 | .get = ovl_other_xattr_get, |
| 1144 | .set = ovl_other_xattr_set, |
| 1145 | }; |
| 1146 | |
| 1147 | static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { |
| 1148 | #ifdef CONFIG_FS_POSIX_ACL |
| 1149 | &ovl_posix_acl_access_xattr_handler, |
| 1150 | &ovl_posix_acl_default_xattr_handler, |
| 1151 | #endif |
| 1152 | &ovl_own_trusted_xattr_handler, |
| 1153 | &ovl_other_xattr_handler, |
| 1154 | NULL |
| 1155 | }; |
| 1156 | |
| 1157 | static const struct xattr_handler *ovl_user_xattr_handlers[] = { |
| 1158 | #ifdef CONFIG_FS_POSIX_ACL |
| 1159 | &ovl_posix_acl_access_xattr_handler, |
| 1160 | &ovl_posix_acl_default_xattr_handler, |
| 1161 | #endif |
| 1162 | &ovl_own_user_xattr_handler, |
| 1163 | &ovl_other_xattr_handler, |
| 1164 | NULL |
| 1165 | }; |
| 1166 | |
| 1167 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
| 1168 | struct inode **ptrap, const char *name) |
| 1169 | { |
| 1170 | struct inode *trap; |
| 1171 | int err; |
| 1172 | |
| 1173 | trap = ovl_get_trap_inode(sb, dir); |
| 1174 | err = PTR_ERR_OR_ZERO(trap); |
| 1175 | if (err) { |
| 1176 | if (err == -ELOOP) |
| 1177 | pr_err("conflicting %s path\n", name); |
| 1178 | return err; |
| 1179 | } |
| 1180 | |
| 1181 | *ptrap = trap; |
| 1182 | return 0; |
| 1183 | } |
| 1184 | |
| 1185 | /* |
| 1186 | * Determine how we treat concurrent use of upperdir/workdir based on the |
| 1187 | * index feature. This is papering over mount leaks of container runtimes, |
| 1188 | * for example, an old overlay mount is leaked and now its upperdir is |
| 1189 | * attempted to be used as a lower layer in a new overlay mount. |
| 1190 | */ |
| 1191 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) |
| 1192 | { |
| 1193 | if (ofs->config.index) { |
| 1194 | pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", |
| 1195 | name); |
| 1196 | return -EBUSY; |
| 1197 | } else { |
| 1198 | pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", |
| 1199 | name); |
| 1200 | return 0; |
| 1201 | } |
| 1202 | } |
| 1203 | |
| 1204 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
| 1205 | struct ovl_layer *upper_layer, struct path *upperpath) |
| 1206 | { |
| 1207 | struct vfsmount *upper_mnt; |
| 1208 | int err; |
| 1209 | |
| 1210 | err = ovl_mount_dir(ofs->config.upperdir, upperpath); |
| 1211 | if (err) |
| 1212 | goto out; |
| 1213 | |
| 1214 | /* Upperdir path should not be r/o */ |
| 1215 | if (__mnt_is_readonly(upperpath->mnt)) { |
| 1216 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
| 1217 | err = -EINVAL; |
| 1218 | goto out; |
| 1219 | } |
| 1220 | |
| 1221 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
| 1222 | if (err) |
| 1223 | goto out; |
| 1224 | |
| 1225 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
| 1226 | "upperdir"); |
| 1227 | if (err) |
| 1228 | goto out; |
| 1229 | |
| 1230 | upper_mnt = clone_private_mount(upperpath); |
| 1231 | err = PTR_ERR(upper_mnt); |
| 1232 | if (IS_ERR(upper_mnt)) { |
| 1233 | pr_err("failed to clone upperpath\n"); |
| 1234 | goto out; |
| 1235 | } |
| 1236 | |
| 1237 | /* Don't inherit atime flags */ |
| 1238 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); |
| 1239 | upper_layer->mnt = upper_mnt; |
| 1240 | upper_layer->idx = 0; |
| 1241 | upper_layer->fsid = 0; |
| 1242 | |
| 1243 | /* |
| 1244 | * Inherit SB_NOSEC flag from upperdir. |
| 1245 | * |
| 1246 | * This optimization changes behavior when a security related attribute |
| 1247 | * (suid/sgid/security.*) is changed on an underlying layer. This is |
| 1248 | * okay because we don't yet have guarantees in that case, but it will |
| 1249 | * need careful treatment once we want to honour changes to underlying |
| 1250 | * filesystems. |
| 1251 | */ |
| 1252 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) |
| 1253 | sb->s_flags |= SB_NOSEC; |
| 1254 | |
| 1255 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
| 1256 | ofs->upperdir_locked = true; |
| 1257 | } else { |
| 1258 | err = ovl_report_in_use(ofs, "upperdir"); |
| 1259 | if (err) |
| 1260 | goto out; |
| 1261 | } |
| 1262 | |
| 1263 | err = 0; |
| 1264 | out: |
| 1265 | return err; |
| 1266 | } |
| 1267 | |
| 1268 | /* |
| 1269 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and |
| 1270 | * negative values if error is encountered. |
| 1271 | */ |
| 1272 | static int ovl_check_rename_whiteout(struct ovl_fs *ofs) |
| 1273 | { |
| 1274 | struct dentry *workdir = ofs->workdir; |
| 1275 | struct inode *dir = d_inode(workdir); |
| 1276 | struct dentry *temp; |
| 1277 | struct dentry *dest; |
| 1278 | struct dentry *whiteout; |
| 1279 | struct name_snapshot name; |
| 1280 | int err; |
| 1281 | |
| 1282 | inode_lock_nested(dir, I_MUTEX_PARENT); |
| 1283 | |
| 1284 | temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); |
| 1285 | err = PTR_ERR(temp); |
| 1286 | if (IS_ERR(temp)) |
| 1287 | goto out_unlock; |
| 1288 | |
| 1289 | dest = ovl_lookup_temp(ofs, workdir); |
| 1290 | err = PTR_ERR(dest); |
| 1291 | if (IS_ERR(dest)) { |
| 1292 | dput(temp); |
| 1293 | goto out_unlock; |
| 1294 | } |
| 1295 | |
| 1296 | /* Name is inline and stable - using snapshot as a copy helper */ |
| 1297 | take_dentry_name_snapshot(&name, temp); |
| 1298 | err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); |
| 1299 | if (err) { |
| 1300 | if (err == -EINVAL) |
| 1301 | err = 0; |
| 1302 | goto cleanup_temp; |
| 1303 | } |
| 1304 | |
| 1305 | whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); |
| 1306 | err = PTR_ERR(whiteout); |
| 1307 | if (IS_ERR(whiteout)) |
| 1308 | goto cleanup_temp; |
| 1309 | |
| 1310 | err = ovl_is_whiteout(whiteout); |
| 1311 | |
| 1312 | /* Best effort cleanup of whiteout and temp file */ |
| 1313 | if (err) |
| 1314 | ovl_cleanup(ofs, dir, whiteout); |
| 1315 | dput(whiteout); |
| 1316 | |
| 1317 | cleanup_temp: |
| 1318 | ovl_cleanup(ofs, dir, temp); |
| 1319 | release_dentry_name_snapshot(&name); |
| 1320 | dput(temp); |
| 1321 | dput(dest); |
| 1322 | |
| 1323 | out_unlock: |
| 1324 | inode_unlock(dir); |
| 1325 | |
| 1326 | return err; |
| 1327 | } |
| 1328 | |
| 1329 | static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, |
| 1330 | struct dentry *parent, |
| 1331 | const char *name, umode_t mode) |
| 1332 | { |
| 1333 | size_t len = strlen(name); |
| 1334 | struct dentry *child; |
| 1335 | |
| 1336 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); |
| 1337 | child = ovl_lookup_upper(ofs, name, parent, len); |
| 1338 | if (!IS_ERR(child) && !child->d_inode) |
| 1339 | child = ovl_create_real(ofs, parent->d_inode, child, |
| 1340 | OVL_CATTR(mode)); |
| 1341 | inode_unlock(parent->d_inode); |
| 1342 | dput(parent); |
| 1343 | |
| 1344 | return child; |
| 1345 | } |
| 1346 | |
| 1347 | /* |
| 1348 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already |
| 1349 | * present. |
| 1350 | */ |
| 1351 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) |
| 1352 | { |
| 1353 | unsigned int ctr; |
| 1354 | struct dentry *d = dget(ofs->workbasedir); |
| 1355 | static const char *const volatile_path[] = { |
| 1356 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" |
| 1357 | }; |
| 1358 | const char *const *name = volatile_path; |
| 1359 | |
| 1360 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { |
| 1361 | d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); |
| 1362 | if (IS_ERR(d)) |
| 1363 | return PTR_ERR(d); |
| 1364 | } |
| 1365 | dput(d); |
| 1366 | return 0; |
| 1367 | } |
| 1368 | |
| 1369 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
| 1370 | const struct path *workpath) |
| 1371 | { |
| 1372 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
| 1373 | struct dentry *workdir; |
| 1374 | struct file *tmpfile; |
| 1375 | bool rename_whiteout; |
| 1376 | bool d_type; |
| 1377 | int fh_type; |
| 1378 | int err; |
| 1379 | |
| 1380 | err = mnt_want_write(mnt); |
| 1381 | if (err) |
| 1382 | return err; |
| 1383 | |
| 1384 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
| 1385 | err = PTR_ERR(workdir); |
| 1386 | if (IS_ERR_OR_NULL(workdir)) |
| 1387 | goto out; |
| 1388 | |
| 1389 | ofs->workdir = workdir; |
| 1390 | |
| 1391 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
| 1392 | if (err) |
| 1393 | goto out; |
| 1394 | |
| 1395 | /* |
| 1396 | * Upper should support d_type, else whiteouts are visible. Given |
| 1397 | * workdir and upper are on same fs, we can do iterate_dir() on |
| 1398 | * workdir. This check requires successful creation of workdir in |
| 1399 | * previous step. |
| 1400 | */ |
| 1401 | err = ovl_check_d_type_supported(workpath); |
| 1402 | if (err < 0) |
| 1403 | goto out; |
| 1404 | |
| 1405 | d_type = err; |
| 1406 | if (!d_type) |
| 1407 | pr_warn("upper fs needs to support d_type.\n"); |
| 1408 | |
| 1409 | /* Check if upper/work fs supports O_TMPFILE */ |
| 1410 | tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); |
| 1411 | ofs->tmpfile = !IS_ERR(tmpfile); |
| 1412 | if (ofs->tmpfile) |
| 1413 | fput(tmpfile); |
| 1414 | else |
| 1415 | pr_warn("upper fs does not support tmpfile.\n"); |
| 1416 | |
| 1417 | |
| 1418 | /* Check if upper/work fs supports RENAME_WHITEOUT */ |
| 1419 | err = ovl_check_rename_whiteout(ofs); |
| 1420 | if (err < 0) |
| 1421 | goto out; |
| 1422 | |
| 1423 | rename_whiteout = err; |
| 1424 | if (!rename_whiteout) |
| 1425 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
| 1426 | |
| 1427 | /* |
| 1428 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
| 1429 | */ |
| 1430 | err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
| 1431 | if (err) { |
| 1432 | pr_warn("failed to set xattr on upper\n"); |
| 1433 | ofs->noxattr = true; |
| 1434 | if (ofs->config.index || ofs->config.metacopy) { |
| 1435 | ofs->config.index = false; |
| 1436 | ofs->config.metacopy = false; |
| 1437 | pr_warn("...falling back to index=off,metacopy=off.\n"); |
| 1438 | } |
| 1439 | /* |
| 1440 | * xattr support is required for persistent st_ino. |
| 1441 | * Without persistent st_ino, xino=auto falls back to xino=off. |
| 1442 | */ |
| 1443 | if (ofs->config.xino == OVL_XINO_AUTO) { |
| 1444 | ofs->config.xino = OVL_XINO_OFF; |
| 1445 | pr_warn("...falling back to xino=off.\n"); |
| 1446 | } |
| 1447 | if (err == -EPERM && !ofs->config.userxattr) |
| 1448 | pr_info("try mounting with 'userxattr' option\n"); |
| 1449 | err = 0; |
| 1450 | } else { |
| 1451 | ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
| 1452 | } |
| 1453 | |
| 1454 | /* |
| 1455 | * We allowed sub-optimal upper fs configuration and don't want to break |
| 1456 | * users over kernel upgrade, but we never allowed remote upper fs, so |
| 1457 | * we can enforce strict requirements for remote upper fs. |
| 1458 | */ |
| 1459 | if (ovl_dentry_remote(ofs->workdir) && |
| 1460 | (!d_type || !rename_whiteout || ofs->noxattr)) { |
| 1461 | pr_err("upper fs missing required features.\n"); |
| 1462 | err = -EINVAL; |
| 1463 | goto out; |
| 1464 | } |
| 1465 | |
| 1466 | /* |
| 1467 | * For volatile mount, create a incompat/volatile/dirty file to keep |
| 1468 | * track of it. |
| 1469 | */ |
| 1470 | if (ofs->config.ovl_volatile) { |
| 1471 | err = ovl_create_volatile_dirty(ofs); |
| 1472 | if (err < 0) { |
| 1473 | pr_err("Failed to create volatile/dirty file.\n"); |
| 1474 | goto out; |
| 1475 | } |
| 1476 | } |
| 1477 | |
| 1478 | /* Check if upper/work fs supports file handles */ |
| 1479 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
| 1480 | if (ofs->config.index && !fh_type) { |
| 1481 | ofs->config.index = false; |
| 1482 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
| 1483 | } |
| 1484 | |
| 1485 | /* Check if upper fs has 32bit inode numbers */ |
| 1486 | if (fh_type != FILEID_INO32_GEN) |
| 1487 | ofs->xino_mode = -1; |
| 1488 | |
| 1489 | /* NFS export of r/w mount depends on index */ |
| 1490 | if (ofs->config.nfs_export && !ofs->config.index) { |
| 1491 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
| 1492 | ofs->config.nfs_export = false; |
| 1493 | } |
| 1494 | out: |
| 1495 | mnt_drop_write(mnt); |
| 1496 | return err; |
| 1497 | } |
| 1498 | |
| 1499 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
| 1500 | const struct path *upperpath) |
| 1501 | { |
| 1502 | int err; |
| 1503 | struct path workpath = { }; |
| 1504 | |
| 1505 | err = ovl_mount_dir(ofs->config.workdir, &workpath); |
| 1506 | if (err) |
| 1507 | goto out; |
| 1508 | |
| 1509 | err = -EINVAL; |
| 1510 | if (upperpath->mnt != workpath.mnt) { |
| 1511 | pr_err("workdir and upperdir must reside under the same mount\n"); |
| 1512 | goto out; |
| 1513 | } |
| 1514 | if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { |
| 1515 | pr_err("workdir and upperdir must be separate subtrees\n"); |
| 1516 | goto out; |
| 1517 | } |
| 1518 | |
| 1519 | ofs->workbasedir = dget(workpath.dentry); |
| 1520 | |
| 1521 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
| 1522 | ofs->workdir_locked = true; |
| 1523 | } else { |
| 1524 | err = ovl_report_in_use(ofs, "workdir"); |
| 1525 | if (err) |
| 1526 | goto out; |
| 1527 | } |
| 1528 | |
| 1529 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
| 1530 | "workdir"); |
| 1531 | if (err) |
| 1532 | goto out; |
| 1533 | |
| 1534 | err = ovl_make_workdir(sb, ofs, &workpath); |
| 1535 | |
| 1536 | out: |
| 1537 | path_put(&workpath); |
| 1538 | |
| 1539 | return err; |
| 1540 | } |
| 1541 | |
| 1542 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
| 1543 | struct ovl_entry *oe, const struct path *upperpath) |
| 1544 | { |
| 1545 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
| 1546 | struct dentry *indexdir; |
| 1547 | int err; |
| 1548 | |
| 1549 | err = mnt_want_write(mnt); |
| 1550 | if (err) |
| 1551 | return err; |
| 1552 | |
| 1553 | /* Verify lower root is upper root origin */ |
| 1554 | err = ovl_verify_origin(ofs, upperpath->dentry, |
| 1555 | oe->lowerstack[0].dentry, true); |
| 1556 | if (err) { |
| 1557 | pr_err("failed to verify upper root origin\n"); |
| 1558 | goto out; |
| 1559 | } |
| 1560 | |
| 1561 | /* index dir will act also as workdir */ |
| 1562 | iput(ofs->workdir_trap); |
| 1563 | ofs->workdir_trap = NULL; |
| 1564 | dput(ofs->workdir); |
| 1565 | ofs->workdir = NULL; |
| 1566 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
| 1567 | if (IS_ERR(indexdir)) { |
| 1568 | err = PTR_ERR(indexdir); |
| 1569 | } else if (indexdir) { |
| 1570 | ofs->indexdir = indexdir; |
| 1571 | ofs->workdir = dget(indexdir); |
| 1572 | |
| 1573 | err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, |
| 1574 | "indexdir"); |
| 1575 | if (err) |
| 1576 | goto out; |
| 1577 | |
| 1578 | /* |
| 1579 | * Verify upper root is exclusively associated with index dir. |
| 1580 | * Older kernels stored upper fh in ".overlay.origin" |
| 1581 | * xattr. If that xattr exists, verify that it is a match to |
| 1582 | * upper dir file handle. In any case, verify or set xattr |
| 1583 | * ".overlay.upper" to indicate that index may have |
| 1584 | * directory entries. |
| 1585 | */ |
| 1586 | if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { |
| 1587 | err = ovl_verify_set_fh(ofs, ofs->indexdir, |
| 1588 | OVL_XATTR_ORIGIN, |
| 1589 | upperpath->dentry, true, false); |
| 1590 | if (err) |
| 1591 | pr_err("failed to verify index dir 'origin' xattr\n"); |
| 1592 | } |
| 1593 | err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, |
| 1594 | true); |
| 1595 | if (err) |
| 1596 | pr_err("failed to verify index dir 'upper' xattr\n"); |
| 1597 | |
| 1598 | /* Cleanup bad/stale/orphan index entries */ |
| 1599 | if (!err) |
| 1600 | err = ovl_indexdir_cleanup(ofs); |
| 1601 | } |
| 1602 | if (err || !ofs->indexdir) |
| 1603 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
| 1604 | |
| 1605 | out: |
| 1606 | mnt_drop_write(mnt); |
| 1607 | return err; |
| 1608 | } |
| 1609 | |
| 1610 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
| 1611 | { |
| 1612 | unsigned int i; |
| 1613 | |
| 1614 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
| 1615 | return true; |
| 1616 | |
| 1617 | /* |
| 1618 | * We allow using single lower with null uuid for index and nfs_export |
| 1619 | * for example to support those features with single lower squashfs. |
| 1620 | * To avoid regressions in setups of overlay with re-formatted lower |
| 1621 | * squashfs, do not allow decoding origin with lower null uuid unless |
| 1622 | * user opted-in to one of the new features that require following the |
| 1623 | * lower inode of non-dir upper. |
| 1624 | */ |
| 1625 | if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) |
| 1626 | return false; |
| 1627 | |
| 1628 | for (i = 0; i < ofs->numfs; i++) { |
| 1629 | /* |
| 1630 | * We use uuid to associate an overlay lower file handle with a |
| 1631 | * lower layer, so we can accept lower fs with null uuid as long |
| 1632 | * as all lower layers with null uuid are on the same fs. |
| 1633 | * if we detect multiple lower fs with the same uuid, we |
| 1634 | * disable lower file handle decoding on all of them. |
| 1635 | */ |
| 1636 | if (ofs->fs[i].is_lower && |
| 1637 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { |
| 1638 | ofs->fs[i].bad_uuid = true; |
| 1639 | return false; |
| 1640 | } |
| 1641 | } |
| 1642 | return true; |
| 1643 | } |
| 1644 | |
| 1645 | /* Get a unique fsid for the layer */ |
| 1646 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
| 1647 | { |
| 1648 | struct super_block *sb = path->mnt->mnt_sb; |
| 1649 | unsigned int i; |
| 1650 | dev_t dev; |
| 1651 | int err; |
| 1652 | bool bad_uuid = false; |
| 1653 | bool warn = false; |
| 1654 | |
| 1655 | for (i = 0; i < ofs->numfs; i++) { |
| 1656 | if (ofs->fs[i].sb == sb) |
| 1657 | return i; |
| 1658 | } |
| 1659 | |
| 1660 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
| 1661 | bad_uuid = true; |
| 1662 | if (ofs->config.xino == OVL_XINO_AUTO) { |
| 1663 | ofs->config.xino = OVL_XINO_OFF; |
| 1664 | warn = true; |
| 1665 | } |
| 1666 | if (ofs->config.index || ofs->config.nfs_export) { |
| 1667 | ofs->config.index = false; |
| 1668 | ofs->config.nfs_export = false; |
| 1669 | warn = true; |
| 1670 | } |
| 1671 | if (warn) { |
| 1672 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", |
| 1673 | uuid_is_null(&sb->s_uuid) ? "null" : |
| 1674 | "conflicting", |
| 1675 | path->dentry, ovl_xino_str[ofs->config.xino]); |
| 1676 | } |
| 1677 | } |
| 1678 | |
| 1679 | err = get_anon_bdev(&dev); |
| 1680 | if (err) { |
| 1681 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
| 1682 | return err; |
| 1683 | } |
| 1684 | |
| 1685 | ofs->fs[ofs->numfs].sb = sb; |
| 1686 | ofs->fs[ofs->numfs].pseudo_dev = dev; |
| 1687 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; |
| 1688 | |
| 1689 | return ofs->numfs++; |
| 1690 | } |
| 1691 | |
| 1692 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
| 1693 | struct path *stack, unsigned int numlower, |
| 1694 | struct ovl_layer *layers) |
| 1695 | { |
| 1696 | int err; |
| 1697 | unsigned int i; |
| 1698 | |
| 1699 | err = -ENOMEM; |
| 1700 | ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); |
| 1701 | if (ofs->fs == NULL) |
| 1702 | goto out; |
| 1703 | |
| 1704 | /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ |
| 1705 | ofs->numfs++; |
| 1706 | |
| 1707 | /* |
| 1708 | * All lower layers that share the same fs as upper layer, use the same |
| 1709 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower |
| 1710 | * only overlay to simplify ovl_fs_free(). |
| 1711 | * is_lower will be set if upper fs is shared with a lower layer. |
| 1712 | */ |
| 1713 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
| 1714 | if (err) { |
| 1715 | pr_err("failed to get anonymous bdev for upper fs\n"); |
| 1716 | goto out; |
| 1717 | } |
| 1718 | |
| 1719 | if (ovl_upper_mnt(ofs)) { |
| 1720 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; |
| 1721 | ofs->fs[0].is_lower = false; |
| 1722 | } |
| 1723 | |
| 1724 | for (i = 0; i < numlower; i++) { |
| 1725 | struct vfsmount *mnt; |
| 1726 | struct inode *trap; |
| 1727 | int fsid; |
| 1728 | |
| 1729 | err = fsid = ovl_get_fsid(ofs, &stack[i]); |
| 1730 | if (err < 0) |
| 1731 | goto out; |
| 1732 | |
| 1733 | /* |
| 1734 | * Check if lower root conflicts with this overlay layers before |
| 1735 | * checking if it is in-use as upperdir/workdir of "another" |
| 1736 | * mount, because we do not bother to check in ovl_is_inuse() if |
| 1737 | * the upperdir/workdir is in fact in-use by our |
| 1738 | * upperdir/workdir. |
| 1739 | */ |
| 1740 | err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); |
| 1741 | if (err) |
| 1742 | goto out; |
| 1743 | |
| 1744 | if (ovl_is_inuse(stack[i].dentry)) { |
| 1745 | err = ovl_report_in_use(ofs, "lowerdir"); |
| 1746 | if (err) { |
| 1747 | iput(trap); |
| 1748 | goto out; |
| 1749 | } |
| 1750 | } |
| 1751 | |
| 1752 | mnt = clone_private_mount(&stack[i]); |
| 1753 | err = PTR_ERR(mnt); |
| 1754 | if (IS_ERR(mnt)) { |
| 1755 | pr_err("failed to clone lowerpath\n"); |
| 1756 | iput(trap); |
| 1757 | goto out; |
| 1758 | } |
| 1759 | |
| 1760 | /* |
| 1761 | * Make lower layers R/O. That way fchmod/fchown on lower file |
| 1762 | * will fail instead of modifying lower fs. |
| 1763 | */ |
| 1764 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; |
| 1765 | |
| 1766 | layers[ofs->numlayer].trap = trap; |
| 1767 | layers[ofs->numlayer].mnt = mnt; |
| 1768 | layers[ofs->numlayer].idx = ofs->numlayer; |
| 1769 | layers[ofs->numlayer].fsid = fsid; |
| 1770 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; |
| 1771 | ofs->numlayer++; |
| 1772 | ofs->fs[fsid].is_lower = true; |
| 1773 | } |
| 1774 | |
| 1775 | /* |
| 1776 | * When all layers on same fs, overlay can use real inode numbers. |
| 1777 | * With mount option "xino=<on|auto>", mounter declares that there are |
| 1778 | * enough free high bits in underlying fs to hold the unique fsid. |
| 1779 | * If overlayfs does encounter underlying inodes using the high xino |
| 1780 | * bits reserved for fsid, it emits a warning and uses the original |
| 1781 | * inode number or a non persistent inode number allocated from a |
| 1782 | * dedicated range. |
| 1783 | */ |
| 1784 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
| 1785 | if (ofs->config.xino == OVL_XINO_ON) |
| 1786 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); |
| 1787 | ofs->xino_mode = 0; |
| 1788 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
| 1789 | ofs->xino_mode = -1; |
| 1790 | } else if (ofs->xino_mode < 0) { |
| 1791 | /* |
| 1792 | * This is a roundup of number of bits needed for encoding |
| 1793 | * fsid, where fsid 0 is reserved for upper fs (even with |
| 1794 | * lower only overlay) +1 extra bit is reserved for the non |
| 1795 | * persistent inode number range that is used for resolving |
| 1796 | * xino lower bits overflow. |
| 1797 | */ |
| 1798 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
| 1799 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; |
| 1800 | } |
| 1801 | |
| 1802 | if (ofs->xino_mode > 0) { |
| 1803 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
| 1804 | ofs->xino_mode); |
| 1805 | } |
| 1806 | |
| 1807 | err = 0; |
| 1808 | out: |
| 1809 | return err; |
| 1810 | } |
| 1811 | |
| 1812 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
| 1813 | const char *lower, unsigned int numlower, |
| 1814 | struct ovl_fs *ofs, struct ovl_layer *layers) |
| 1815 | { |
| 1816 | int err; |
| 1817 | struct path *stack = NULL; |
| 1818 | unsigned int i; |
| 1819 | struct ovl_entry *oe; |
| 1820 | |
| 1821 | if (!ofs->config.upperdir && numlower == 1) { |
| 1822 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
| 1823 | return ERR_PTR(-EINVAL); |
| 1824 | } |
| 1825 | |
| 1826 | stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); |
| 1827 | if (!stack) |
| 1828 | return ERR_PTR(-ENOMEM); |
| 1829 | |
| 1830 | err = -EINVAL; |
| 1831 | for (i = 0; i < numlower; i++) { |
| 1832 | err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); |
| 1833 | if (err) |
| 1834 | goto out_err; |
| 1835 | |
| 1836 | lower = strchr(lower, '\0') + 1; |
| 1837 | } |
| 1838 | |
| 1839 | err = -EINVAL; |
| 1840 | sb->s_stack_depth++; |
| 1841 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { |
| 1842 | pr_err("maximum fs stacking depth exceeded\n"); |
| 1843 | goto out_err; |
| 1844 | } |
| 1845 | |
| 1846 | err = ovl_get_layers(sb, ofs, stack, numlower, layers); |
| 1847 | if (err) |
| 1848 | goto out_err; |
| 1849 | |
| 1850 | err = -ENOMEM; |
| 1851 | oe = ovl_alloc_entry(numlower); |
| 1852 | if (!oe) |
| 1853 | goto out_err; |
| 1854 | |
| 1855 | for (i = 0; i < numlower; i++) { |
| 1856 | oe->lowerstack[i].dentry = dget(stack[i].dentry); |
| 1857 | oe->lowerstack[i].layer = &ofs->layers[i+1]; |
| 1858 | } |
| 1859 | |
| 1860 | out: |
| 1861 | for (i = 0; i < numlower; i++) |
| 1862 | path_put(&stack[i]); |
| 1863 | kfree(stack); |
| 1864 | |
| 1865 | return oe; |
| 1866 | |
| 1867 | out_err: |
| 1868 | oe = ERR_PTR(err); |
| 1869 | goto out; |
| 1870 | } |
| 1871 | |
| 1872 | /* |
| 1873 | * Check if this layer root is a descendant of: |
| 1874 | * - another layer of this overlayfs instance |
| 1875 | * - upper/work dir of any overlayfs instance |
| 1876 | */ |
| 1877 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
| 1878 | struct dentry *dentry, const char *name, |
| 1879 | bool is_lower) |
| 1880 | { |
| 1881 | struct dentry *next = dentry, *parent; |
| 1882 | int err = 0; |
| 1883 | |
| 1884 | if (!dentry) |
| 1885 | return 0; |
| 1886 | |
| 1887 | parent = dget_parent(next); |
| 1888 | |
| 1889 | /* Walk back ancestors to root (inclusive) looking for traps */ |
| 1890 | while (!err && parent != next) { |
| 1891 | if (is_lower && ovl_lookup_trap_inode(sb, parent)) { |
| 1892 | err = -ELOOP; |
| 1893 | pr_err("overlapping %s path\n", name); |
| 1894 | } else if (ovl_is_inuse(parent)) { |
| 1895 | err = ovl_report_in_use(ofs, name); |
| 1896 | } |
| 1897 | next = parent; |
| 1898 | parent = dget_parent(next); |
| 1899 | dput(next); |
| 1900 | } |
| 1901 | |
| 1902 | dput(parent); |
| 1903 | |
| 1904 | return err; |
| 1905 | } |
| 1906 | |
| 1907 | /* |
| 1908 | * Check if any of the layers or work dirs overlap. |
| 1909 | */ |
| 1910 | static int ovl_check_overlapping_layers(struct super_block *sb, |
| 1911 | struct ovl_fs *ofs) |
| 1912 | { |
| 1913 | int i, err; |
| 1914 | |
| 1915 | if (ovl_upper_mnt(ofs)) { |
| 1916 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, |
| 1917 | "upperdir", false); |
| 1918 | if (err) |
| 1919 | return err; |
| 1920 | |
| 1921 | /* |
| 1922 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of |
| 1923 | * this instance and covers overlapping work and index dirs, |
| 1924 | * unless work or index dir have been moved since created inside |
| 1925 | * workbasedir. In that case, we already have their traps in |
| 1926 | * inode cache and we will catch that case on lookup. |
| 1927 | */ |
| 1928 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", |
| 1929 | false); |
| 1930 | if (err) |
| 1931 | return err; |
| 1932 | } |
| 1933 | |
| 1934 | for (i = 1; i < ofs->numlayer; i++) { |
| 1935 | err = ovl_check_layer(sb, ofs, |
| 1936 | ofs->layers[i].mnt->mnt_root, |
| 1937 | "lowerdir", true); |
| 1938 | if (err) |
| 1939 | return err; |
| 1940 | } |
| 1941 | |
| 1942 | return 0; |
| 1943 | } |
| 1944 | |
| 1945 | static struct dentry *ovl_get_root(struct super_block *sb, |
| 1946 | struct dentry *upperdentry, |
| 1947 | struct ovl_entry *oe) |
| 1948 | { |
| 1949 | struct dentry *root; |
| 1950 | struct ovl_path *lowerpath = &oe->lowerstack[0]; |
| 1951 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; |
| 1952 | int fsid = lowerpath->layer->fsid; |
| 1953 | struct ovl_inode_params oip = { |
| 1954 | .upperdentry = upperdentry, |
| 1955 | .lowerpath = lowerpath, |
| 1956 | }; |
| 1957 | |
| 1958 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); |
| 1959 | if (!root) |
| 1960 | return NULL; |
| 1961 | |
| 1962 | root->d_fsdata = oe; |
| 1963 | |
| 1964 | if (upperdentry) { |
| 1965 | /* Root inode uses upper st_ino/i_ino */ |
| 1966 | ino = d_inode(upperdentry)->i_ino; |
| 1967 | fsid = 0; |
| 1968 | ovl_dentry_set_upper_alias(root); |
| 1969 | if (ovl_is_impuredir(sb, upperdentry)) |
| 1970 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
| 1971 | } |
| 1972 | |
| 1973 | /* Root is always merge -> can have whiteouts */ |
| 1974 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); |
| 1975 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); |
| 1976 | ovl_set_upperdata(d_inode(root)); |
| 1977 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
| 1978 | ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); |
| 1979 | |
| 1980 | return root; |
| 1981 | } |
| 1982 | |
| 1983 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
| 1984 | { |
| 1985 | struct path upperpath = { }; |
| 1986 | struct dentry *root_dentry; |
| 1987 | struct ovl_entry *oe; |
| 1988 | struct ovl_fs *ofs; |
| 1989 | struct ovl_layer *layers; |
| 1990 | struct cred *cred; |
| 1991 | char *splitlower = NULL; |
| 1992 | unsigned int numlower; |
| 1993 | int err; |
| 1994 | |
| 1995 | err = -EIO; |
| 1996 | if (WARN_ON(sb->s_user_ns != current_user_ns())) |
| 1997 | goto out; |
| 1998 | |
| 1999 | sb->s_d_op = &ovl_dentry_operations; |
| 2000 | |
| 2001 | err = -ENOMEM; |
| 2002 | ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); |
| 2003 | if (!ofs) |
| 2004 | goto out; |
| 2005 | |
| 2006 | err = -ENOMEM; |
| 2007 | ofs->creator_cred = cred = prepare_creds(); |
| 2008 | if (!cred) |
| 2009 | goto out_err; |
| 2010 | |
| 2011 | /* Is there a reason anyone would want not to share whiteouts? */ |
| 2012 | ofs->share_whiteout = true; |
| 2013 | |
| 2014 | ofs->config.index = ovl_index_def; |
| 2015 | ofs->config.uuid = true; |
| 2016 | ofs->config.nfs_export = ovl_nfs_export_def; |
| 2017 | ofs->config.xino = ovl_xino_def(); |
| 2018 | ofs->config.metacopy = ovl_metacopy_def; |
| 2019 | err = ovl_parse_opt((char *) data, &ofs->config); |
| 2020 | if (err) |
| 2021 | goto out_err; |
| 2022 | |
| 2023 | err = -EINVAL; |
| 2024 | if (!ofs->config.lowerdir) { |
| 2025 | if (!silent) |
| 2026 | pr_err("missing 'lowerdir'\n"); |
| 2027 | goto out_err; |
| 2028 | } |
| 2029 | |
| 2030 | err = -ENOMEM; |
| 2031 | splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); |
| 2032 | if (!splitlower) |
| 2033 | goto out_err; |
| 2034 | |
| 2035 | err = -EINVAL; |
| 2036 | numlower = ovl_split_lowerdirs(splitlower); |
| 2037 | if (numlower > OVL_MAX_STACK) { |
| 2038 | pr_err("too many lower directories, limit is %d\n", |
| 2039 | OVL_MAX_STACK); |
| 2040 | goto out_err; |
| 2041 | } |
| 2042 | |
| 2043 | err = -ENOMEM; |
| 2044 | layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); |
| 2045 | if (!layers) |
| 2046 | goto out_err; |
| 2047 | |
| 2048 | ofs->layers = layers; |
| 2049 | /* Layer 0 is reserved for upper even if there's no upper */ |
| 2050 | ofs->numlayer = 1; |
| 2051 | |
| 2052 | sb->s_stack_depth = 0; |
| 2053 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
| 2054 | atomic_long_set(&ofs->last_ino, 1); |
| 2055 | /* Assume underlying fs uses 32bit inodes unless proven otherwise */ |
| 2056 | if (ofs->config.xino != OVL_XINO_OFF) { |
| 2057 | ofs->xino_mode = BITS_PER_LONG - 32; |
| 2058 | if (!ofs->xino_mode) { |
| 2059 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); |
| 2060 | ofs->config.xino = OVL_XINO_OFF; |
| 2061 | } |
| 2062 | } |
| 2063 | |
| 2064 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
| 2065 | sb->s_op = &ovl_super_operations; |
| 2066 | |
| 2067 | if (ofs->config.upperdir) { |
| 2068 | struct super_block *upper_sb; |
| 2069 | |
| 2070 | err = -EINVAL; |
| 2071 | if (!ofs->config.workdir) { |
| 2072 | pr_err("missing 'workdir'\n"); |
| 2073 | goto out_err; |
| 2074 | } |
| 2075 | |
| 2076 | err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); |
| 2077 | if (err) |
| 2078 | goto out_err; |
| 2079 | |
| 2080 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
| 2081 | if (!ovl_should_sync(ofs)) { |
| 2082 | ofs->errseq = errseq_sample(&upper_sb->s_wb_err); |
| 2083 | if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { |
| 2084 | err = -EIO; |
| 2085 | pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); |
| 2086 | goto out_err; |
| 2087 | } |
| 2088 | } |
| 2089 | |
| 2090 | err = ovl_get_workdir(sb, ofs, &upperpath); |
| 2091 | if (err) |
| 2092 | goto out_err; |
| 2093 | |
| 2094 | if (!ofs->workdir) |
| 2095 | sb->s_flags |= SB_RDONLY; |
| 2096 | |
| 2097 | sb->s_stack_depth = upper_sb->s_stack_depth; |
| 2098 | sb->s_time_gran = upper_sb->s_time_gran; |
| 2099 | } |
| 2100 | oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); |
| 2101 | err = PTR_ERR(oe); |
| 2102 | if (IS_ERR(oe)) |
| 2103 | goto out_err; |
| 2104 | |
| 2105 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
| 2106 | if (!ovl_upper_mnt(ofs)) |
| 2107 | sb->s_flags |= SB_RDONLY; |
| 2108 | |
| 2109 | if (!ofs->config.uuid && ofs->numfs > 1) { |
| 2110 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); |
| 2111 | ofs->config.uuid = true; |
| 2112 | } |
| 2113 | |
| 2114 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
| 2115 | err = ovl_get_indexdir(sb, ofs, oe, &upperpath); |
| 2116 | if (err) |
| 2117 | goto out_free_oe; |
| 2118 | |
| 2119 | /* Force r/o mount with no index dir */ |
| 2120 | if (!ofs->indexdir) |
| 2121 | sb->s_flags |= SB_RDONLY; |
| 2122 | } |
| 2123 | |
| 2124 | err = ovl_check_overlapping_layers(sb, ofs); |
| 2125 | if (err) |
| 2126 | goto out_free_oe; |
| 2127 | |
| 2128 | /* Show index=off in /proc/mounts for forced r/o mount */ |
| 2129 | if (!ofs->indexdir) { |
| 2130 | ofs->config.index = false; |
| 2131 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
| 2132 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
| 2133 | ofs->config.nfs_export = false; |
| 2134 | } |
| 2135 | } |
| 2136 | |
| 2137 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
| 2138 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
| 2139 | ofs->config.nfs_export = false; |
| 2140 | } |
| 2141 | |
| 2142 | if (ofs->config.nfs_export) |
| 2143 | sb->s_export_op = &ovl_export_operations; |
| 2144 | |
| 2145 | /* Never override disk quota limits or use reserved space */ |
| 2146 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); |
| 2147 | |
| 2148 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
| 2149 | sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : |
| 2150 | ovl_trusted_xattr_handlers; |
| 2151 | sb->s_fs_info = ofs; |
| 2152 | sb->s_flags |= SB_POSIXACL; |
| 2153 | sb->s_iflags |= SB_I_SKIP_SYNC; |
| 2154 | |
| 2155 | err = -ENOMEM; |
| 2156 | root_dentry = ovl_get_root(sb, upperpath.dentry, oe); |
| 2157 | if (!root_dentry) |
| 2158 | goto out_free_oe; |
| 2159 | |
| 2160 | mntput(upperpath.mnt); |
| 2161 | kfree(splitlower); |
| 2162 | |
| 2163 | sb->s_root = root_dentry; |
| 2164 | |
| 2165 | return 0; |
| 2166 | |
| 2167 | out_free_oe: |
| 2168 | ovl_entry_stack_free(oe); |
| 2169 | kfree(oe); |
| 2170 | out_err: |
| 2171 | kfree(splitlower); |
| 2172 | path_put(&upperpath); |
| 2173 | ovl_free_fs(ofs); |
| 2174 | out: |
| 2175 | return err; |
| 2176 | } |
| 2177 | |
| 2178 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, |
| 2179 | const char *dev_name, void *raw_data) |
| 2180 | { |
| 2181 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); |
| 2182 | } |
| 2183 | |
| 2184 | static struct file_system_type ovl_fs_type = { |
| 2185 | .owner = THIS_MODULE, |
| 2186 | .name = "overlay", |
| 2187 | .fs_flags = FS_USERNS_MOUNT, |
| 2188 | .mount = ovl_mount, |
| 2189 | .kill_sb = kill_anon_super, |
| 2190 | }; |
| 2191 | MODULE_ALIAS_FS("overlay"); |
| 2192 | |
| 2193 | static void ovl_inode_init_once(void *foo) |
| 2194 | { |
| 2195 | struct ovl_inode *oi = foo; |
| 2196 | |
| 2197 | inode_init_once(&oi->vfs_inode); |
| 2198 | } |
| 2199 | |
| 2200 | static int __init ovl_init(void) |
| 2201 | { |
| 2202 | int err; |
| 2203 | |
| 2204 | ovl_inode_cachep = kmem_cache_create("ovl_inode", |
| 2205 | sizeof(struct ovl_inode), 0, |
| 2206 | (SLAB_RECLAIM_ACCOUNT| |
| 2207 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), |
| 2208 | ovl_inode_init_once); |
| 2209 | if (ovl_inode_cachep == NULL) |
| 2210 | return -ENOMEM; |
| 2211 | |
| 2212 | err = ovl_aio_request_cache_init(); |
| 2213 | if (!err) { |
| 2214 | err = register_filesystem(&ovl_fs_type); |
| 2215 | if (!err) |
| 2216 | return 0; |
| 2217 | |
| 2218 | ovl_aio_request_cache_destroy(); |
| 2219 | } |
| 2220 | kmem_cache_destroy(ovl_inode_cachep); |
| 2221 | |
| 2222 | return err; |
| 2223 | } |
| 2224 | |
| 2225 | static void __exit ovl_exit(void) |
| 2226 | { |
| 2227 | unregister_filesystem(&ovl_fs_type); |
| 2228 | |
| 2229 | /* |
| 2230 | * Make sure all delayed rcu free inodes are flushed before we |
| 2231 | * destroy cache. |
| 2232 | */ |
| 2233 | rcu_barrier(); |
| 2234 | kmem_cache_destroy(ovl_inode_cachep); |
| 2235 | ovl_aio_request_cache_destroy(); |
| 2236 | } |
| 2237 | |
| 2238 | module_init(ovl_init); |
| 2239 | module_exit(ovl_exit); |