1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * 4 * Copyright (C) 2011 Novell Inc. 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/uuid.h> 9 #include <linux/fs.h> 10 #include <linux/fsverity.h> 11 #include <linux/namei.h> 12 #include <linux/posix_acl.h> 13 #include <linux/posix_acl_xattr.h> 14 #include "ovl_entry.h" 15 16 #undef pr_fmt 17 #define pr_fmt(fmt) "overlayfs: " fmt 18 19 enum ovl_path_type { 20 __OVL_PATH_UPPER = (1 << 0), 21 __OVL_PATH_MERGE = (1 << 1), 22 __OVL_PATH_ORIGIN = (1 << 2), 23 }; 24 25 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 26 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 27 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 28 29 #define OVL_XATTR_NAMESPACE "overlay." 30 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE 31 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE 32 33 enum ovl_xattr { 34 OVL_XATTR_OPAQUE, 35 OVL_XATTR_REDIRECT, 36 OVL_XATTR_ORIGIN, 37 OVL_XATTR_IMPURE, 38 OVL_XATTR_NLINK, 39 OVL_XATTR_UPPER, 40 OVL_XATTR_UUID, 41 OVL_XATTR_METACOPY, 42 OVL_XATTR_PROTATTR, 43 }; 44 45 enum ovl_inode_flag { 46 /* Pure upper dir that may contain non pure upper entries */ 47 OVL_IMPURE, 48 /* Non-merge dir that may contain whiteout entries */ 49 OVL_WHITEOUTS, 50 OVL_INDEX, 51 OVL_UPPERDATA, 52 /* Inode number will remain constant over copy up. */ 53 OVL_CONST_INO, 54 OVL_HAS_DIGEST, 55 OVL_VERIFIED_DIGEST, 56 }; 57 58 enum ovl_entry_flag { 59 OVL_E_UPPER_ALIAS, 60 OVL_E_OPAQUE, 61 OVL_E_CONNECTED, 62 }; 63 64 enum { 65 OVL_REDIRECT_OFF, /* "off" mode is never used. In effect */ 66 OVL_REDIRECT_FOLLOW, /* ...it translates to either "follow" */ 67 OVL_REDIRECT_NOFOLLOW, /* ...or "nofollow". */ 68 OVL_REDIRECT_ON, 69 }; 70 71 enum { 72 OVL_UUID_OFF, 73 OVL_UUID_NULL, 74 OVL_UUID_AUTO, 75 OVL_UUID_ON, 76 }; 77 78 enum { 79 OVL_XINO_OFF, 80 OVL_XINO_AUTO, 81 OVL_XINO_ON, 82 }; 83 84 enum { 85 OVL_VERITY_OFF, 86 OVL_VERITY_ON, 87 OVL_VERITY_REQUIRE, 88 }; 89 90 /* 91 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 92 * where: 93 * origin.fh - exported file handle of the lower file 94 * origin.uuid - uuid of the lower filesystem 95 */ 96 #define OVL_FH_VERSION 0 97 #define OVL_FH_MAGIC 0xfb 98 99 /* CPU byte order required for fid decoding: */ 100 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 101 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 102 /* Is the real inode encoded in fid an upper inode? */ 103 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 104 105 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 106 OVL_FH_FLAG_PATH_UPPER) 107 108 #if defined(__LITTLE_ENDIAN) 109 #define OVL_FH_FLAG_CPU_ENDIAN 0 110 #elif defined(__BIG_ENDIAN) 111 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 112 #else 113 #error Endianness not defined 114 #endif 115 116 /* The type used to be returned by overlay exportfs for misaligned fid */ 117 #define OVL_FILEID_V0 0xfb 118 /* The type returned by overlay exportfs for 32bit aligned fid */ 119 #define OVL_FILEID_V1 0xf8 120 121 /* On-disk format for "origin" file handle */ 122 struct ovl_fb { 123 u8 version; /* 0 */ 124 u8 magic; /* 0xfb */ 125 u8 len; /* size of this header + size of fid */ 126 u8 flags; /* OVL_FH_FLAG_* */ 127 u8 type; /* fid_type of fid */ 128 uuid_t uuid; /* uuid of filesystem */ 129 u32 fid[]; /* file identifier should be 32bit aligned in-memory */ 130 } __packed; 131 132 /* In-memory and on-wire format for overlay file handle */ 133 struct ovl_fh { 134 u8 padding[3]; /* make sure fb.fid is 32bit aligned */ 135 union { 136 struct ovl_fb fb; 137 DECLARE_FLEX_ARRAY(u8, buf); 138 }; 139 } __packed; 140 141 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) 142 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) 143 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ 144 offsetof(struct ovl_fb, fid)) 145 146 /* On-disk format for "metacopy" xattr (if non-zero size) */ 147 struct ovl_metacopy { 148 u8 version; /* 0 */ 149 u8 len; /* size of this header + used digest bytes */ 150 u8 flags; 151 u8 digest_algo; /* FS_VERITY_HASH_ALG_* constant, 0 for no digest */ 152 u8 digest[FS_VERITY_MAX_DIGEST_SIZE]; /* Only the used part on disk */ 153 } __packed; 154 155 #define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy)) 156 #define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE) 157 #define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE } 158 159 static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy) 160 { 161 if (metacopy->len < OVL_METACOPY_MIN_SIZE) 162 return 0; 163 return (int)metacopy->len - OVL_METACOPY_MIN_SIZE; 164 } 165 166 extern const char *const ovl_xattr_table[][2]; 167 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) 168 { 169 return ovl_xattr_table[ox][ofs->config.userxattr]; 170 } 171 172 /* 173 * When changing ownership of an upper object map the intended ownership 174 * according to the upper layer's idmapping. When an upper mount idmaps files 175 * that are stored on-disk as owned by id 1001 to id 1000 this means stat on 176 * this object will report it as being owned by id 1000 when calling stat via 177 * the upper mount. 178 * In order to change ownership of an object so stat reports id 1000 when 179 * called on an idmapped upper mount the value written to disk - i.e., the 180 * value stored in ia_*id - must 1001. The mount mapping helper will thus take 181 * care to map 1000 to 1001. 182 * The mnt idmapping helpers are nops if the upper layer isn't idmapped. 183 */ 184 static inline int ovl_do_notify_change(struct ovl_fs *ofs, 185 struct dentry *upperdentry, 186 struct iattr *attr) 187 { 188 return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL); 189 } 190 191 static inline int ovl_do_rmdir(struct ovl_fs *ofs, 192 struct inode *dir, struct dentry *dentry) 193 { 194 int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry); 195 196 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 197 return err; 198 } 199 200 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir, 201 struct dentry *dentry) 202 { 203 int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL); 204 205 pr_debug("unlink(%pd2) = %i\n", dentry, err); 206 return err; 207 } 208 209 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry, 210 struct inode *dir, struct dentry *new_dentry) 211 { 212 int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir, 213 new_dentry, NULL); 214 215 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 216 return err; 217 } 218 219 static inline int ovl_do_create(struct ovl_fs *ofs, 220 struct inode *dir, struct dentry *dentry, 221 umode_t mode) 222 { 223 int err = vfs_create(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, true); 224 225 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 226 return err; 227 } 228 229 static inline int ovl_do_mkdir(struct ovl_fs *ofs, 230 struct inode *dir, struct dentry *dentry, 231 umode_t mode) 232 { 233 int err = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode); 234 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 235 return err; 236 } 237 238 static inline int ovl_do_mknod(struct ovl_fs *ofs, 239 struct inode *dir, struct dentry *dentry, 240 umode_t mode, dev_t dev) 241 { 242 int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev); 243 244 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 245 return err; 246 } 247 248 static inline int ovl_do_symlink(struct ovl_fs *ofs, 249 struct inode *dir, struct dentry *dentry, 250 const char *oldname) 251 { 252 int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname); 253 254 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 255 return err; 256 } 257 258 static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name, 259 void *value, size_t size) 260 { 261 int err, len; 262 263 WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb); 264 265 err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry, 266 name, value, size); 267 len = (value && err > 0) ? err : 0; 268 269 pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", 270 path->dentry, name, min(len, 48), value, size, err); 271 return err; 272 } 273 274 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs, 275 struct dentry *upperdentry, 276 enum ovl_xattr ox, void *value, 277 size_t size) 278 { 279 struct path upperpath = { 280 .dentry = upperdentry, 281 .mnt = ovl_upper_mnt(ofs), 282 }; 283 284 return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size); 285 } 286 287 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs, 288 const struct path *path, 289 enum ovl_xattr ox, void *value, 290 size_t size) 291 { 292 return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size); 293 } 294 295 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 296 const char *name, const void *value, 297 size_t size, int flags) 298 { 299 int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name, 300 value, size, flags); 301 302 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n", 303 dentry, name, min((int)size, 48), value, size, flags, err); 304 return err; 305 } 306 307 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 308 enum ovl_xattr ox, const void *value, 309 size_t size) 310 { 311 return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0); 312 } 313 314 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 315 const char *name) 316 { 317 int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name); 318 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 319 return err; 320 } 321 322 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 323 enum ovl_xattr ox) 324 { 325 return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox)); 326 } 327 328 static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry, 329 const char *acl_name, struct posix_acl *acl) 330 { 331 return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl); 332 } 333 334 static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry, 335 const char *acl_name) 336 { 337 return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name); 338 } 339 340 static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir, 341 struct dentry *olddentry, struct inode *newdir, 342 struct dentry *newdentry, unsigned int flags) 343 { 344 int err; 345 struct renamedata rd = { 346 .old_mnt_idmap = ovl_upper_mnt_idmap(ofs), 347 .old_dir = olddir, 348 .old_dentry = olddentry, 349 .new_mnt_idmap = ovl_upper_mnt_idmap(ofs), 350 .new_dir = newdir, 351 .new_dentry = newdentry, 352 .flags = flags, 353 }; 354 355 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); 356 err = vfs_rename(&rd); 357 if (err) { 358 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 359 olddentry, newdentry, err); 360 } 361 return err; 362 } 363 364 static inline int ovl_do_whiteout(struct ovl_fs *ofs, 365 struct inode *dir, struct dentry *dentry) 366 { 367 int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry); 368 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 369 return err; 370 } 371 372 static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs, 373 struct dentry *dentry, umode_t mode) 374 { 375 struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry }; 376 struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path, 377 mode, O_LARGEFILE | O_WRONLY, 378 current_cred()); 379 int err = PTR_ERR_OR_ZERO(file); 380 381 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 382 return file; 383 } 384 385 static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs, 386 const char *name, 387 struct dentry *base, int len) 388 { 389 return lookup_one(ovl_upper_mnt_idmap(ofs), name, base, len); 390 } 391 392 static inline bool ovl_open_flags_need_copy_up(int flags) 393 { 394 if (!flags) 395 return false; 396 397 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 398 } 399 400 /* util.c */ 401 int ovl_want_write(struct dentry *dentry); 402 void ovl_drop_write(struct dentry *dentry); 403 struct dentry *ovl_workdir(struct dentry *dentry); 404 const struct cred *ovl_override_creds(struct super_block *sb); 405 int ovl_can_decode_fh(struct super_block *sb); 406 struct dentry *ovl_indexdir(struct super_block *sb); 407 bool ovl_index_all(struct super_block *sb); 408 bool ovl_verify_lower(struct super_block *sb); 409 struct ovl_path *ovl_stack_alloc(unsigned int n); 410 void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n); 411 void ovl_stack_put(struct ovl_path *stack, unsigned int n); 412 void ovl_stack_free(struct ovl_path *stack, unsigned int n); 413 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 414 void ovl_free_entry(struct ovl_entry *oe); 415 bool ovl_dentry_remote(struct dentry *dentry); 416 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry); 417 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry, 418 struct ovl_entry *oe); 419 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, 420 struct ovl_entry *oe, unsigned int mask); 421 bool ovl_dentry_weird(struct dentry *dentry); 422 enum ovl_path_type ovl_path_type(struct dentry *dentry); 423 void ovl_path_upper(struct dentry *dentry, struct path *path); 424 void ovl_path_lower(struct dentry *dentry, struct path *path); 425 void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 426 struct inode *ovl_i_path_real(struct inode *inode, struct path *path); 427 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 428 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path); 429 struct dentry *ovl_dentry_upper(struct dentry *dentry); 430 struct dentry *ovl_dentry_lower(struct dentry *dentry); 431 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 432 int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath); 433 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode); 434 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 435 struct dentry *ovl_dentry_real(struct dentry *dentry); 436 struct dentry *ovl_i_dentry_upper(struct inode *inode); 437 struct inode *ovl_inode_upper(struct inode *inode); 438 struct inode *ovl_inode_lower(struct inode *inode); 439 struct inode *ovl_inode_lowerdata(struct inode *inode); 440 struct inode *ovl_inode_real(struct inode *inode); 441 struct inode *ovl_inode_realdata(struct inode *inode); 442 const char *ovl_lowerdata_redirect(struct inode *inode); 443 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 444 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 445 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 446 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 447 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 448 bool ovl_dentry_is_opaque(struct dentry *dentry); 449 bool ovl_dentry_is_whiteout(struct dentry *dentry); 450 void ovl_dentry_set_opaque(struct dentry *dentry); 451 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 452 void ovl_dentry_set_upper_alias(struct dentry *dentry); 453 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 454 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 455 bool ovl_has_upperdata(struct inode *inode); 456 void ovl_set_upperdata(struct inode *inode); 457 const char *ovl_dentry_get_redirect(struct dentry *dentry); 458 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 459 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 460 void ovl_dir_modified(struct dentry *dentry, bool impurity); 461 u64 ovl_inode_version_get(struct inode *inode); 462 bool ovl_is_whiteout(struct dentry *dentry); 463 struct file *ovl_path_open(const struct path *path, int flags); 464 int ovl_copy_up_start(struct dentry *dentry, int flags); 465 void ovl_copy_up_end(struct dentry *dentry); 466 bool ovl_already_copied_up(struct dentry *dentry, int flags); 467 bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path, 468 enum ovl_xattr ox); 469 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path); 470 bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs, 471 const struct path *upperpath); 472 473 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs, 474 struct dentry *upperdentry) 475 { 476 struct path upperpath = { 477 .dentry = upperdentry, 478 .mnt = ovl_upper_mnt(ofs), 479 }; 480 return ovl_path_check_origin_xattr(ofs, &upperpath); 481 } 482 483 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, 484 enum ovl_xattr ox, const void *value, size_t size, 485 int xerr); 486 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 487 bool ovl_inuse_trylock(struct dentry *dentry); 488 void ovl_inuse_unlock(struct dentry *dentry); 489 bool ovl_is_inuse(struct dentry *dentry); 490 bool ovl_need_index(struct dentry *dentry); 491 int ovl_nlink_start(struct dentry *dentry); 492 void ovl_nlink_end(struct dentry *dentry); 493 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 494 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path, 495 struct ovl_metacopy *data); 496 int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d, 497 struct ovl_metacopy *metacopy); 498 bool ovl_is_metacopy_dentry(struct dentry *dentry); 499 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding); 500 int ovl_ensure_verity_loaded(struct path *path); 501 int ovl_get_verity_xattr(struct ovl_fs *ofs, const struct path *path, 502 u8 *digest_buf, int *buf_length); 503 int ovl_validate_verity(struct ovl_fs *ofs, 504 struct path *metapath, 505 struct path *datapath); 506 int ovl_get_verity_digest(struct ovl_fs *ofs, struct path *src, 507 struct ovl_metacopy *metacopy); 508 int ovl_sync_status(struct ovl_fs *ofs); 509 510 static inline void ovl_set_flag(unsigned long flag, struct inode *inode) 511 { 512 set_bit(flag, &OVL_I(inode)->flags); 513 } 514 515 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode) 516 { 517 clear_bit(flag, &OVL_I(inode)->flags); 518 } 519 520 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode) 521 { 522 return test_bit(flag, &OVL_I(inode)->flags); 523 } 524 525 static inline bool ovl_is_impuredir(struct super_block *sb, 526 struct dentry *upperdentry) 527 { 528 struct ovl_fs *ofs = OVL_FS(sb); 529 struct path upperpath = { 530 .dentry = upperdentry, 531 .mnt = ovl_upper_mnt(ofs), 532 }; 533 534 return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE); 535 } 536 537 static inline bool ovl_redirect_follow(struct ovl_fs *ofs) 538 { 539 return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW; 540 } 541 542 static inline bool ovl_redirect_dir(struct ovl_fs *ofs) 543 { 544 return ofs->config.redirect_mode == OVL_REDIRECT_ON; 545 } 546 547 static inline bool ovl_origin_uuid(struct ovl_fs *ofs) 548 { 549 return ofs->config.uuid != OVL_UUID_OFF; 550 } 551 552 static inline bool ovl_has_fsid(struct ovl_fs *ofs) 553 { 554 return ofs->config.uuid == OVL_UUID_ON || 555 ofs->config.uuid == OVL_UUID_AUTO; 556 } 557 558 /* 559 * With xino=auto, we do best effort to keep all inodes on same st_dev and 560 * d_ino consistent with st_ino. 561 * With xino=on, we do the same effort but we warn if we failed. 562 */ 563 static inline bool ovl_xino_warn(struct ovl_fs *ofs) 564 { 565 return ofs->config.xino == OVL_XINO_ON; 566 } 567 568 /* 569 * To avoid regressions in existing setups with overlay lower offline changes, 570 * we allow lower changes only if none of the new features are used. 571 */ 572 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs) 573 { 574 return (!ofs->config.index && !ofs->config.metacopy && 575 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs)); 576 } 577 578 /* All layers on same fs? */ 579 static inline bool ovl_same_fs(struct ovl_fs *ofs) 580 { 581 return ofs->xino_mode == 0; 582 } 583 584 /* All overlay inodes have same st_dev? */ 585 static inline bool ovl_same_dev(struct ovl_fs *ofs) 586 { 587 return ofs->xino_mode >= 0; 588 } 589 590 static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs) 591 { 592 return ovl_same_dev(ofs) ? ofs->xino_mode : 0; 593 } 594 595 static inline void ovl_inode_lock(struct inode *inode) 596 { 597 mutex_lock(&OVL_I(inode)->lock); 598 } 599 600 static inline int ovl_inode_lock_interruptible(struct inode *inode) 601 { 602 return mutex_lock_interruptible(&OVL_I(inode)->lock); 603 } 604 605 static inline void ovl_inode_unlock(struct inode *inode) 606 { 607 mutex_unlock(&OVL_I(inode)->lock); 608 } 609 610 611 /* namei.c */ 612 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); 613 614 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) 615 { 616 if (fh_len < sizeof(struct ovl_fh)) 617 return -EINVAL; 618 619 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); 620 } 621 622 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, 623 struct vfsmount *mnt, bool connected); 624 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 625 struct dentry *upperdentry, struct ovl_path **stackp); 626 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, 627 enum ovl_xattr ox, struct dentry *real, bool is_upper, 628 bool set); 629 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index, 630 bool connected); 631 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 632 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin, 633 struct qstr *name); 634 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 635 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 636 struct dentry *origin, bool verify); 637 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 638 int ovl_verify_lowerdata(struct dentry *dentry); 639 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 640 unsigned int flags); 641 bool ovl_lower_positive(struct dentry *dentry); 642 643 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, 644 struct dentry *origin, bool set) 645 { 646 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, 647 false, set); 648 } 649 650 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, 651 struct dentry *upper, bool set) 652 { 653 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); 654 } 655 656 /* readdir.c */ 657 extern const struct file_operations ovl_dir_operations; 658 struct file *ovl_dir_real_file(const struct file *file, bool want_upper); 659 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 660 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper, 661 struct list_head *list); 662 void ovl_cache_free(struct list_head *list); 663 void ovl_dir_cache_free(struct inode *inode); 664 int ovl_check_d_type_supported(const struct path *realpath); 665 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir, 666 struct vfsmount *mnt, struct dentry *dentry, int level); 667 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 668 669 /* 670 * Can we iterate real dir directly? 671 * 672 * Non-merge dir may contain whiteouts from a time it was a merge upper, before 673 * lower dir was removed under it and possibly before it was rotated from upper 674 * to lower layer. 675 */ 676 static inline bool ovl_dir_is_real(struct inode *dir) 677 { 678 return !ovl_test_flag(OVL_WHITEOUTS, dir); 679 } 680 681 /* inode.c */ 682 int ovl_set_nlink_upper(struct dentry *dentry); 683 int ovl_set_nlink_lower(struct dentry *dentry); 684 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 685 struct dentry *upperdentry, 686 unsigned int fallback); 687 int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 688 struct iattr *attr); 689 int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, 690 struct kstat *stat, u32 request_mask, unsigned int flags); 691 int ovl_permission(struct mnt_idmap *idmap, struct inode *inode, 692 int mask); 693 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 694 const void *value, size_t size, int flags); 695 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 696 void *value, size_t size); 697 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 698 699 #ifdef CONFIG_FS_POSIX_ACL 700 struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap, 701 struct inode *inode, int type, 702 bool rcu, bool noperm); 703 static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type, 704 bool rcu) 705 { 706 return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true); 707 } 708 static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap, 709 struct dentry *dentry, int type) 710 { 711 return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false); 712 } 713 int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, 714 struct posix_acl *acl, int type); 715 struct posix_acl *ovl_get_acl_path(const struct path *path, 716 const char *acl_name, bool noperm); 717 #else 718 #define ovl_get_inode_acl NULL 719 #define ovl_get_acl NULL 720 #define ovl_set_acl NULL 721 static inline struct posix_acl *ovl_get_acl_path(const struct path *path, 722 const char *acl_name, 723 bool noperm) 724 { 725 return NULL; 726 } 727 #endif 728 729 int ovl_update_time(struct inode *inode, int flags); 730 bool ovl_is_private_xattr(struct super_block *sb, const char *name); 731 732 struct ovl_inode_params { 733 struct inode *newinode; 734 struct dentry *upperdentry; 735 struct ovl_entry *oe; 736 bool index; 737 char *redirect; 738 char *lowerdata_redirect; 739 }; 740 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 741 unsigned long ino, int fsid); 742 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 743 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 744 bool is_upper); 745 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); 746 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); 747 struct inode *ovl_get_inode(struct super_block *sb, 748 struct ovl_inode_params *oip); 749 void ovl_copyattr(struct inode *to); 750 751 /* vfs inode flags copied from real to ovl inode */ 752 #define OVL_COPY_I_FLAGS_MASK (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE) 753 /* vfs inode flags read from overlay.protattr xattr to ovl inode */ 754 #define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE) 755 756 /* 757 * fileattr flags copied from lower to upper inode on copy up. 758 * We cannot copy up immutable/append-only flags, because that would prevent 759 * linking temp inode to upper dir, so we store them in xattr instead. 760 */ 761 #define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL) 762 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME) 763 #define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL) 764 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE) 765 766 void ovl_check_protattr(struct inode *inode, struct dentry *upper); 767 int ovl_set_protattr(struct inode *inode, struct dentry *upper, 768 struct fileattr *fa); 769 770 static inline void ovl_copyflags(struct inode *from, struct inode *to) 771 { 772 unsigned int mask = OVL_COPY_I_FLAGS_MASK; 773 774 inode_set_flags(to, from->i_flags & mask, mask); 775 } 776 777 /* dir.c */ 778 extern const struct inode_operations ovl_dir_inode_operations; 779 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, 780 struct dentry *dentry); 781 struct ovl_cattr { 782 dev_t rdev; 783 umode_t mode; 784 const char *link; 785 struct dentry *hardlink; 786 }; 787 788 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 789 790 int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir, 791 struct dentry **newdentry, umode_t mode); 792 struct dentry *ovl_create_real(struct ovl_fs *ofs, 793 struct inode *dir, struct dentry *newdentry, 794 struct ovl_cattr *attr); 795 int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry); 796 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir); 797 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir, 798 struct ovl_cattr *attr); 799 800 /* file.c */ 801 extern const struct file_operations ovl_file_operations; 802 int __init ovl_aio_request_cache_init(void); 803 void ovl_aio_request_cache_destroy(void); 804 int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa); 805 int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa); 806 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa); 807 int ovl_fileattr_set(struct mnt_idmap *idmap, 808 struct dentry *dentry, struct fileattr *fa); 809 810 /* copy_up.c */ 811 int ovl_copy_up(struct dentry *dentry); 812 int ovl_copy_up_with_data(struct dentry *dentry); 813 int ovl_maybe_copy_up(struct dentry *dentry, int flags); 814 int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new); 815 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat); 816 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, 817 bool is_upper); 818 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower, 819 struct dentry *upper); 820 821 /* export.c */ 822 extern const struct export_operations ovl_export_operations; 823 extern const struct export_operations ovl_export_fid_operations; 824 825 /* super.c */ 826 int ovl_fill_super(struct super_block *sb, struct fs_context *fc); 827 828 /* Will this overlay be forced to mount/remount ro? */ 829 static inline bool ovl_force_readonly(struct ovl_fs *ofs) 830 { 831 return (!ovl_upper_mnt(ofs) || !ofs->workdir); 832 } 833