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_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) 32 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE 33 #define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1) 34 35 #define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE 36 #define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1) 37 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX 38 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1) 39 #define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX 40 #define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1) 41 42 enum ovl_xattr { 43 OVL_XATTR_OPAQUE, 44 OVL_XATTR_REDIRECT, 45 OVL_XATTR_ORIGIN, 46 OVL_XATTR_IMPURE, 47 OVL_XATTR_NLINK, 48 OVL_XATTR_UPPER, 49 OVL_XATTR_UUID, 50 OVL_XATTR_METACOPY, 51 OVL_XATTR_PROTATTR, 52 OVL_XATTR_XWHITEOUT, 53 }; 54 55 enum ovl_inode_flag { 56 /* Pure upper dir that may contain non pure upper entries */ 57 OVL_IMPURE, 58 /* Non-merge dir that may contain whiteout entries */ 59 OVL_WHITEOUTS, 60 OVL_INDEX, 61 OVL_UPPERDATA, 62 /* Inode number will remain constant over copy up. */ 63 OVL_CONST_INO, 64 OVL_HAS_DIGEST, 65 OVL_VERIFIED_DIGEST, 66 }; 67 68 enum ovl_entry_flag { 69 OVL_E_UPPER_ALIAS, 70 OVL_E_OPAQUE, 71 OVL_E_CONNECTED, 72 /* Lower stack may contain xwhiteout entries */ 73 OVL_E_XWHITEOUTS, 74 }; 75 76 enum { 77 OVL_REDIRECT_OFF, /* "off" mode is never used. In effect */ 78 OVL_REDIRECT_FOLLOW, /* ...it translates to either "follow" */ 79 OVL_REDIRECT_NOFOLLOW, /* ...or "nofollow". */ 80 OVL_REDIRECT_ON, 81 }; 82 83 enum { 84 OVL_UUID_OFF, 85 OVL_UUID_NULL, 86 OVL_UUID_AUTO, 87 OVL_UUID_ON, 88 }; 89 90 enum { 91 OVL_XINO_OFF, 92 OVL_XINO_AUTO, 93 OVL_XINO_ON, 94 }; 95 96 enum { 97 OVL_VERITY_OFF, 98 OVL_VERITY_ON, 99 OVL_VERITY_REQUIRE, 100 }; 101 102 enum { 103 OVL_FSYNC_VOLATILE, 104 OVL_FSYNC_AUTO, 105 OVL_FSYNC_STRICT, 106 }; 107 108 /* 109 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 110 * where: 111 * origin.fh - exported file handle of the lower file 112 * origin.uuid - uuid of the lower filesystem 113 */ 114 #define OVL_FH_VERSION 0 115 #define OVL_FH_MAGIC 0xfb 116 117 /* CPU byte order required for fid decoding: */ 118 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 119 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 120 /* Is the real inode encoded in fid an upper inode? */ 121 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 122 123 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 124 OVL_FH_FLAG_PATH_UPPER) 125 126 #if defined(__LITTLE_ENDIAN) 127 #define OVL_FH_FLAG_CPU_ENDIAN 0 128 #elif defined(__BIG_ENDIAN) 129 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 130 #else 131 #error Endianness not defined 132 #endif 133 134 /* The type used to be returned by overlay exportfs for misaligned fid */ 135 #define OVL_FILEID_V0 0xfb 136 /* The type returned by overlay exportfs for 32bit aligned fid */ 137 #define OVL_FILEID_V1 0xf8 138 139 /* On-disk format for "origin" file handle */ 140 struct ovl_fb { 141 u8 version; /* 0 */ 142 u8 magic; /* 0xfb */ 143 u8 len; /* size of this header + size of fid */ 144 u8 flags; /* OVL_FH_FLAG_* */ 145 u8 type; /* fid_type of fid */ 146 uuid_t uuid; /* uuid of filesystem */ 147 u32 fid[]; /* file identifier should be 32bit aligned in-memory */ 148 } __packed; 149 150 /* In-memory and on-wire format for overlay file handle */ 151 struct ovl_fh { 152 u8 padding[3]; /* make sure fb.fid is 32bit aligned */ 153 union { 154 struct ovl_fb fb; 155 DECLARE_FLEX_ARRAY(u8, buf); 156 }; 157 } __packed; 158 159 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) 160 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) 161 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ 162 offsetof(struct ovl_fb, fid)) 163 164 /* On-disk format for "metacopy" xattr (if non-zero size) */ 165 struct ovl_metacopy { 166 u8 version; /* 0 */ 167 u8 len; /* size of this header + used digest bytes */ 168 u8 flags; 169 u8 digest_algo; /* FS_VERITY_HASH_ALG_* constant, 0 for no digest */ 170 u8 digest[FS_VERITY_MAX_DIGEST_SIZE]; /* Only the used part on disk */ 171 } __packed; 172 173 #define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy)) 174 #define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE) 175 #define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE } 176 177 static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy) 178 { 179 if (metacopy->len < OVL_METACOPY_MIN_SIZE) 180 return 0; 181 return (int)metacopy->len - OVL_METACOPY_MIN_SIZE; 182 } 183 184 /* No atime modification on underlying */ 185 #define OVL_OPEN_FLAGS (O_NOATIME) 186 187 extern const char *const ovl_xattr_table[][2]; 188 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) 189 { 190 return ovl_xattr_table[ox][ofs->config.userxattr]; 191 } 192 193 /* 194 * When changing ownership of an upper object map the intended ownership 195 * according to the upper layer's idmapping. When an upper mount idmaps files 196 * that are stored on-disk as owned by id 1001 to id 1000 this means stat on 197 * this object will report it as being owned by id 1000 when calling stat via 198 * the upper mount. 199 * In order to change ownership of an object so stat reports id 1000 when 200 * called on an idmapped upper mount the value written to disk - i.e., the 201 * value stored in ia_*id - must 1001. The mount mapping helper will thus take 202 * care to map 1000 to 1001. 203 * The mnt idmapping helpers are nops if the upper layer isn't idmapped. 204 */ 205 static inline int ovl_do_notify_change(struct ovl_fs *ofs, 206 struct dentry *upperdentry, 207 struct iattr *attr) 208 { 209 return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL); 210 } 211 212 static inline int ovl_do_rmdir(struct ovl_fs *ofs, 213 struct inode *dir, struct dentry *dentry) 214 { 215 int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL); 216 217 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 218 return err; 219 } 220 221 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir, 222 struct dentry *dentry) 223 { 224 int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL); 225 226 pr_debug("unlink(%pd2) = %i\n", dentry, err); 227 return err; 228 } 229 230 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry, 231 struct inode *dir, struct dentry *new_dentry) 232 { 233 int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir, 234 new_dentry, NULL); 235 236 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 237 return err; 238 } 239 240 static inline int ovl_do_create(struct ovl_fs *ofs, 241 struct inode *dir, struct dentry *dentry, 242 umode_t mode) 243 { 244 int err = vfs_create(ovl_upper_mnt_idmap(ofs), dentry, mode, NULL); 245 246 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 247 return err; 248 } 249 250 static inline struct dentry *ovl_do_mkdir(struct ovl_fs *ofs, 251 struct inode *dir, 252 struct dentry *dentry, 253 umode_t mode) 254 { 255 struct dentry *ret; 256 257 ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, NULL); 258 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, PTR_ERR_OR_ZERO(ret)); 259 return ret; 260 } 261 262 static inline int ovl_do_mknod(struct ovl_fs *ofs, 263 struct inode *dir, struct dentry *dentry, 264 umode_t mode, dev_t dev) 265 { 266 int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev, NULL); 267 268 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 269 return err; 270 } 271 272 static inline int ovl_do_symlink(struct ovl_fs *ofs, 273 struct inode *dir, struct dentry *dentry, 274 const char *oldname) 275 { 276 int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname, NULL); 277 278 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 279 return err; 280 } 281 282 static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name, 283 void *value, size_t size) 284 { 285 int err, len; 286 287 WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb); 288 289 err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry, 290 name, value, size); 291 len = (value && err > 0) ? err : 0; 292 293 pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", 294 path->dentry, name, min(len, 48), value, size, err); 295 return err; 296 } 297 298 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs, 299 struct dentry *upperdentry, 300 enum ovl_xattr ox, void *value, 301 size_t size) 302 { 303 struct path upperpath = { 304 .dentry = upperdentry, 305 .mnt = ovl_upper_mnt(ofs), 306 }; 307 308 return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size); 309 } 310 311 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs, 312 const struct path *path, 313 enum ovl_xattr ox, void *value, 314 size_t size) 315 { 316 return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size); 317 } 318 319 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 320 const char *name, const void *value, 321 size_t size, int flags) 322 { 323 int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name, 324 value, size, flags); 325 326 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n", 327 dentry, name, min((int)size, 48), value, size, flags, err); 328 return err; 329 } 330 331 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 332 enum ovl_xattr ox, const void *value, 333 size_t size) 334 { 335 return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0); 336 } 337 338 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 339 const char *name) 340 { 341 int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name); 342 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 343 return err; 344 } 345 346 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 347 enum ovl_xattr ox) 348 { 349 return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox)); 350 } 351 352 static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry, 353 const char *acl_name, struct posix_acl *acl) 354 { 355 return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl); 356 } 357 358 static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry, 359 const char *acl_name) 360 { 361 return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name); 362 } 363 364 static inline int ovl_do_rename_rd(struct renamedata *rd) 365 { 366 int err; 367 368 pr_debug("rename(%pd2, %pd2, 0x%x)\n", rd->old_dentry, rd->new_dentry, 369 rd->flags); 370 err = vfs_rename(rd); 371 if (err) { 372 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 373 rd->old_dentry, rd->new_dentry, err); 374 } 375 return err; 376 } 377 378 static inline int ovl_do_rename(struct ovl_fs *ofs, struct dentry *olddir, 379 struct dentry *olddentry, struct dentry *newdir, 380 struct dentry *newdentry, unsigned int flags) 381 { 382 struct renamedata rd = { 383 .mnt_idmap = ovl_upper_mnt_idmap(ofs), 384 .old_parent = olddir, 385 .old_dentry = olddentry, 386 .new_parent = newdir, 387 .new_dentry = newdentry, 388 .flags = flags, 389 }; 390 391 return ovl_do_rename_rd(&rd); 392 } 393 394 static inline int ovl_do_whiteout(struct ovl_fs *ofs, 395 struct inode *dir, struct dentry *dentry) 396 { 397 int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry); 398 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 399 return err; 400 } 401 402 static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs, 403 struct dentry *dentry, umode_t mode) 404 { 405 struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry }; 406 struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path, 407 mode, O_LARGEFILE | O_WRONLY, 408 current_cred()); 409 int err = PTR_ERR_OR_ZERO(file); 410 411 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 412 return file; 413 } 414 415 static inline struct dentry *ovl_lookup_upper_unlocked(struct ovl_fs *ofs, 416 const char *name, 417 struct dentry *base, 418 int len) 419 { 420 return lookup_one_unlocked(ovl_upper_mnt_idmap(ofs), 421 &QSTR_LEN(name, len), base); 422 } 423 424 static inline struct dentry *ovl_start_creating_upper(struct ovl_fs *ofs, 425 struct dentry *parent, 426 struct qstr *name) 427 { 428 return start_creating(ovl_upper_mnt_idmap(ofs), 429 parent, name); 430 } 431 432 static inline struct dentry *ovl_start_removing_upper(struct ovl_fs *ofs, 433 struct dentry *parent, 434 struct qstr *name) 435 { 436 return start_removing(ovl_upper_mnt_idmap(ofs), 437 parent, name); 438 } 439 440 static inline bool ovl_open_flags_need_copy_up(int flags) 441 { 442 if (!flags) 443 return false; 444 445 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 446 } 447 448 /* util.c */ 449 int ovl_get_write_access(struct dentry *dentry); 450 void ovl_put_write_access(struct dentry *dentry); 451 void ovl_start_write(struct dentry *dentry); 452 void ovl_end_write(struct dentry *dentry); 453 int ovl_want_write(struct dentry *dentry); 454 void ovl_drop_write(struct dentry *dentry); 455 struct dentry *ovl_workdir(struct dentry *dentry); 456 const struct cred *ovl_override_creds(struct super_block *sb); 457 458 EXTEND_CLASS(override_creds, _ovl, ovl_override_creds(sb), struct super_block *sb) 459 460 #define with_ovl_creds(sb) \ 461 scoped_class(override_creds_ovl, __UNIQUE_ID(label), sb) 462 463 static inline const struct cred *ovl_creds(struct super_block *sb) 464 { 465 return OVL_FS(sb)->creator_cred; 466 } 467 468 int ovl_can_decode_fh(struct super_block *sb); 469 struct dentry *ovl_indexdir(struct super_block *sb); 470 bool ovl_index_all(struct super_block *sb); 471 bool ovl_verify_lower(struct super_block *sb); 472 struct ovl_path *ovl_stack_alloc(unsigned int n); 473 void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n); 474 void ovl_stack_put(struct ovl_path *stack, unsigned int n); 475 void ovl_stack_free(struct ovl_path *stack, unsigned int n); 476 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 477 void ovl_free_entry(struct ovl_entry *oe); 478 bool ovl_dentry_remote(struct dentry *dentry); 479 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry); 480 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry, 481 struct ovl_entry *oe); 482 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, 483 struct ovl_entry *oe, unsigned int mask); 484 bool ovl_dentry_weird(struct dentry *dentry); 485 486 static inline bool ovl_dentry_casefolded(struct dentry *dentry) 487 { 488 return sb_has_encoding(dentry->d_sb) && IS_CASEFOLDED(d_inode(dentry)); 489 } 490 491 enum ovl_path_type ovl_path_type(struct dentry *dentry); 492 void ovl_path_upper(struct dentry *dentry, struct path *path); 493 void ovl_path_lower(struct dentry *dentry, struct path *path); 494 void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 495 struct inode *ovl_i_path_real(struct inode *inode, struct path *path); 496 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 497 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path); 498 struct dentry *ovl_dentry_upper(struct dentry *dentry); 499 struct dentry *ovl_dentry_lower(struct dentry *dentry); 500 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 501 int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath); 502 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode); 503 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 504 struct dentry *ovl_dentry_real(struct dentry *dentry); 505 struct dentry *ovl_i_dentry_upper(struct inode *inode); 506 struct inode *ovl_inode_upper(struct inode *inode); 507 struct inode *ovl_inode_lower(struct inode *inode); 508 struct inode *ovl_inode_lowerdata(struct inode *inode); 509 struct inode *ovl_inode_real(struct inode *inode); 510 struct inode *ovl_inode_realdata(struct inode *inode); 511 const char *ovl_lowerdata_redirect(struct inode *inode); 512 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 513 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 514 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 515 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 516 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 517 bool ovl_dentry_is_opaque(struct dentry *dentry); 518 bool ovl_dentry_is_whiteout(struct dentry *dentry); 519 void ovl_dentry_set_opaque(struct dentry *dentry); 520 bool ovl_dentry_has_xwhiteouts(struct dentry *dentry); 521 void ovl_dentry_set_xwhiteouts(struct dentry *dentry); 522 void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs, 523 const struct ovl_layer *layer); 524 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 525 void ovl_dentry_set_upper_alias(struct dentry *dentry); 526 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 527 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 528 bool ovl_has_upperdata(struct inode *inode); 529 void ovl_set_upperdata(struct inode *inode); 530 const char *ovl_dentry_get_redirect(struct dentry *dentry); 531 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 532 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 533 void ovl_dir_modified(struct dentry *dentry, bool impurity); 534 u64 ovl_inode_version_get(struct inode *inode); 535 bool ovl_is_whiteout(struct dentry *dentry); 536 bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path); 537 struct file *ovl_path_open(const struct path *path, int flags); 538 int ovl_copy_up_start(struct dentry *dentry, int flags); 539 void ovl_copy_up_end(struct dentry *dentry); 540 bool ovl_already_copied_up(struct dentry *dentry, int flags); 541 char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path, 542 enum ovl_xattr ox); 543 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path); 544 bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path); 545 bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs, 546 const struct path *upperpath); 547 548 static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs, 549 struct dentry *upperdentry) 550 { 551 struct path upperpath = { 552 .dentry = upperdentry, 553 .mnt = ovl_upper_mnt(ofs), 554 }; 555 return ovl_path_is_whiteout(ofs, &upperpath); 556 } 557 558 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs, 559 struct dentry *upperdentry) 560 { 561 struct path upperpath = { 562 .dentry = upperdentry, 563 .mnt = ovl_upper_mnt(ofs), 564 }; 565 return ovl_path_check_origin_xattr(ofs, &upperpath); 566 } 567 568 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, 569 enum ovl_xattr ox, const void *value, size_t size, 570 int xerr); 571 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 572 bool ovl_inuse_trylock(struct dentry *dentry); 573 void ovl_inuse_unlock(struct dentry *dentry); 574 bool ovl_is_inuse(struct dentry *dentry); 575 bool ovl_need_index(struct dentry *dentry); 576 int ovl_nlink_start(struct dentry *dentry); 577 void ovl_nlink_end(struct dentry *dentry); 578 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path, 579 struct ovl_metacopy *data); 580 int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d, 581 struct ovl_metacopy *metacopy); 582 bool ovl_is_metacopy_dentry(struct dentry *dentry); 583 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding); 584 int ovl_ensure_verity_loaded(const struct path *path); 585 int ovl_validate_verity(struct ovl_fs *ofs, 586 const struct path *metapath, 587 const struct path *datapath); 588 int ovl_get_verity_digest(struct ovl_fs *ofs, const struct path *src, 589 struct ovl_metacopy *metacopy); 590 int ovl_sync_status(struct ovl_fs *ofs); 591 592 static inline void ovl_set_flag(unsigned long flag, struct inode *inode) 593 { 594 set_bit(flag, &OVL_I(inode)->flags); 595 } 596 597 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode) 598 { 599 clear_bit(flag, &OVL_I(inode)->flags); 600 } 601 602 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode) 603 { 604 return test_bit(flag, &OVL_I(inode)->flags); 605 } 606 607 static inline bool ovl_is_impuredir(struct super_block *sb, 608 struct dentry *upperdentry) 609 { 610 struct ovl_fs *ofs = OVL_FS(sb); 611 struct path upperpath = { 612 .dentry = upperdentry, 613 .mnt = ovl_upper_mnt(ofs), 614 }; 615 616 return ovl_get_dir_xattr_val(ofs, &upperpath, OVL_XATTR_IMPURE) == 'y'; 617 } 618 619 static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs, 620 const struct path *path) 621 { 622 return ovl_get_dir_xattr_val(ofs, path, OVL_XATTR_OPAQUE); 623 } 624 625 static inline bool ovl_redirect_follow(struct ovl_fs *ofs) 626 { 627 return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW; 628 } 629 630 static inline bool ovl_redirect_dir(struct ovl_fs *ofs) 631 { 632 return ofs->config.redirect_mode == OVL_REDIRECT_ON; 633 } 634 635 static inline bool ovl_origin_uuid(struct ovl_fs *ofs) 636 { 637 return ofs->config.uuid != OVL_UUID_OFF; 638 } 639 640 static inline bool ovl_has_fsid(struct ovl_fs *ofs) 641 { 642 return ofs->config.uuid == OVL_UUID_ON || 643 ofs->config.uuid == OVL_UUID_AUTO; 644 } 645 646 /* 647 * With xino=auto, we do best effort to keep all inodes on same st_dev and 648 * d_ino consistent with st_ino. 649 * With xino=on, we do the same effort but we warn if we failed. 650 */ 651 static inline bool ovl_xino_warn(struct ovl_fs *ofs) 652 { 653 return ofs->config.xino == OVL_XINO_ON; 654 } 655 656 static inline bool ovl_should_sync(struct ovl_fs *ofs) 657 { 658 return ofs->config.fsync_mode != OVL_FSYNC_VOLATILE; 659 } 660 661 static inline bool ovl_should_sync_metadata(struct ovl_fs *ofs) 662 { 663 return ofs->config.fsync_mode == OVL_FSYNC_STRICT; 664 } 665 666 static inline bool ovl_is_volatile(struct ovl_config *config) 667 { 668 return config->fsync_mode == OVL_FSYNC_VOLATILE; 669 } 670 671 /* 672 * To avoid regressions in existing setups with overlay lower offline changes, 673 * we allow lower changes only if none of the new features are used. 674 */ 675 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs) 676 { 677 return (!ofs->config.index && !ofs->config.metacopy && 678 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs)); 679 } 680 681 /* All layers on same fs? */ 682 static inline bool ovl_same_fs(struct ovl_fs *ofs) 683 { 684 return ofs->xino_mode == 0; 685 } 686 687 /* All overlay inodes have same st_dev? */ 688 static inline bool ovl_same_dev(struct ovl_fs *ofs) 689 { 690 return ofs->xino_mode >= 0; 691 } 692 693 static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs) 694 { 695 return ovl_same_dev(ofs) ? ofs->xino_mode : 0; 696 } 697 698 static inline void ovl_inode_lock(struct inode *inode) 699 { 700 mutex_lock(&OVL_I(inode)->lock); 701 } 702 703 static inline int ovl_inode_lock_interruptible(struct inode *inode) 704 { 705 return mutex_lock_interruptible(&OVL_I(inode)->lock); 706 } 707 708 static inline void ovl_inode_unlock(struct inode *inode) 709 { 710 mutex_unlock(&OVL_I(inode)->lock); 711 } 712 713 714 /* namei.c */ 715 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); 716 717 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) 718 { 719 if (fh_len < sizeof(struct ovl_fh)) 720 return -EINVAL; 721 722 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); 723 } 724 725 bool ovl_uuid_match(struct ovl_fs *ofs, const struct super_block *sb, 726 const uuid_t *uuid); 727 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, 728 struct vfsmount *mnt, bool connected); 729 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 730 struct dentry *upperdentry, struct ovl_path **stackp); 731 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, 732 enum ovl_xattr ox, const struct ovl_fh *fh, 733 bool is_upper, bool set); 734 int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry, 735 enum ovl_xattr ox, struct dentry *real, 736 bool is_upper, bool set); 737 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index, 738 bool connected); 739 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 740 int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name); 741 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin, 742 struct qstr *name); 743 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 744 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 745 struct dentry *origin, bool verify); 746 int ovl_path_next(int idx, struct dentry *dentry, struct path *path, 747 const struct ovl_layer **layer); 748 int ovl_verify_lowerdata(struct dentry *dentry); 749 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 750 unsigned int flags); 751 bool ovl_lower_positive(struct dentry *dentry); 752 753 static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper, 754 const struct ovl_fh *fh, bool set) 755 { 756 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set); 757 } 758 759 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, 760 struct dentry *origin, bool set) 761 { 762 return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin, 763 false, set); 764 } 765 766 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, 767 struct dentry *upper, bool set) 768 { 769 return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper, 770 true, set); 771 } 772 773 /* readdir.c */ 774 extern const struct file_operations ovl_dir_operations; 775 struct file *ovl_dir_real_file(const struct file *file, bool want_upper); 776 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 777 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper, 778 struct list_head *list); 779 void ovl_cache_free(struct list_head *list); 780 void ovl_dir_cache_free(struct inode *inode); 781 int ovl_check_d_type_supported(const struct path *realpath); 782 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent, 783 struct vfsmount *mnt, struct dentry *dentry, int level); 784 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 785 786 /* 787 * Can we iterate real dir directly? 788 * 789 * Non-merge dir may contain whiteouts from a time it was a merge upper, before 790 * lower dir was removed under it and possibly before it was rotated from upper 791 * to lower layer. 792 */ 793 static inline bool ovl_dir_is_real(struct inode *dir) 794 { 795 return !ovl_test_flag(OVL_WHITEOUTS, dir); 796 } 797 798 /* inode.c */ 799 int ovl_set_nlink_upper(struct dentry *dentry); 800 int ovl_set_nlink_lower(struct dentry *dentry); 801 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 802 struct dentry *upperdentry, 803 unsigned int fallback); 804 int ovl_permission(struct mnt_idmap *idmap, struct inode *inode, 805 int mask); 806 807 #ifdef CONFIG_FS_POSIX_ACL 808 struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap, 809 struct inode *inode, int type, 810 bool rcu, bool noperm); 811 static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type, 812 bool rcu) 813 { 814 return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true); 815 } 816 static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap, 817 struct dentry *dentry, int type) 818 { 819 return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false); 820 } 821 int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, 822 struct posix_acl *acl, int type); 823 struct posix_acl *ovl_get_acl_path(const struct path *path, 824 const char *acl_name, bool noperm); 825 #else 826 #define ovl_get_inode_acl NULL 827 #define ovl_get_acl NULL 828 #define ovl_set_acl NULL 829 static inline struct posix_acl *ovl_get_acl_path(const struct path *path, 830 const char *acl_name, 831 bool noperm) 832 { 833 return NULL; 834 } 835 #endif 836 837 int ovl_update_time(struct inode *inode, enum fs_update_time type, 838 unsigned int flags); 839 bool ovl_is_private_xattr(struct super_block *sb, const char *name); 840 841 struct ovl_inode_params { 842 struct inode *newinode; 843 struct dentry *upperdentry; 844 struct ovl_entry *oe; 845 bool index; 846 char *redirect; 847 char *lowerdata_redirect; 848 }; 849 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 850 unsigned long ino, int fsid); 851 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 852 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 853 bool is_upper); 854 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); 855 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); 856 struct inode *ovl_get_inode(struct super_block *sb, 857 struct ovl_inode_params *oip); 858 void ovl_copyattr(struct inode *to); 859 860 /* vfs fileattr flags read from overlay.protattr xattr to ovl inode */ 861 #define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE) 862 /* vfs fileattr flags copied from real to ovl inode */ 863 #define OVL_FATTR_I_FLAGS_MASK (OVL_PROT_I_FLAGS_MASK | S_SYNC | S_NOATIME) 864 /* vfs inode flags copied from real to ovl inode */ 865 #define OVL_COPY_I_FLAGS_MASK (OVL_FATTR_I_FLAGS_MASK | S_CASEFOLD) 866 867 /* 868 * fileattr flags copied from lower to upper inode on copy up. 869 * We cannot copy up immutable/append-only flags, because that would prevent 870 * linking temp inode to upper dir, so we store them in xattr instead. 871 */ 872 #define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL) 873 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME) 874 #define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL) 875 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE) 876 877 void ovl_check_protattr(struct inode *inode, struct dentry *upper); 878 int ovl_set_protattr(struct inode *inode, struct dentry *upper, 879 struct file_kattr *fa); 880 881 static inline void ovl_copyflags(struct inode *from, struct inode *to) 882 { 883 unsigned int mask = OVL_COPY_I_FLAGS_MASK; 884 885 inode_set_flags(to, from->i_flags & mask, mask); 886 } 887 888 /* dir.c */ 889 extern const struct inode_operations ovl_dir_inode_operations; 890 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir, 891 struct dentry *dentry); 892 struct ovl_cattr { 893 dev_t rdev; 894 umode_t mode; 895 const char *link; 896 struct dentry *hardlink; 897 }; 898 899 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 900 901 struct dentry *ovl_create_real(struct ovl_fs *ofs, 902 struct dentry *parent, struct dentry *newdentry, 903 struct qstr *qname, 904 struct ovl_cattr *attr); 905 int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir, struct dentry *dentry); 906 #define OVL_TEMPNAME_SIZE 20 907 void ovl_tempname(char name[OVL_TEMPNAME_SIZE]); 908 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir, 909 struct ovl_cattr *attr); 910 911 /* file.c */ 912 extern const struct file_operations ovl_file_operations; 913 int ovl_real_fileattr_get(const struct path *realpath, struct file_kattr *fa); 914 int ovl_real_fileattr_set(const struct path *realpath, struct file_kattr *fa); 915 int ovl_fileattr_get(struct dentry *dentry, struct file_kattr *fa); 916 int ovl_fileattr_set(struct mnt_idmap *idmap, 917 struct dentry *dentry, struct file_kattr *fa); 918 struct ovl_file; 919 struct ovl_file *ovl_file_alloc(struct file *realfile); 920 void ovl_file_free(struct ovl_file *of); 921 922 /* copy_up.c */ 923 int ovl_copy_up(struct dentry *dentry); 924 int ovl_copy_up_with_data(struct dentry *dentry); 925 int ovl_maybe_copy_up(struct dentry *dentry, int flags); 926 int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new); 927 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat); 928 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct inode *realinode, 929 bool is_upper); 930 struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin); 931 int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh, 932 struct dentry *upper); 933 934 /* export.c */ 935 extern const struct export_operations ovl_export_operations; 936 extern const struct export_operations ovl_export_fid_operations; 937 938 /* super.c */ 939 int ovl_fill_super(struct super_block *sb, struct fs_context *fc); 940 941 /* Will this overlay be forced to mount/remount ro? */ 942 static inline bool ovl_force_readonly(struct ovl_fs *ofs) 943 { 944 return (!ovl_upper_mnt(ofs) || !ofs->workdir); 945 } 946 947 /* xattr.c */ 948 949 const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs); 950 int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 951 struct iattr *attr); 952 int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, 953 struct kstat *stat, u32 request_mask, unsigned int flags); 954 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 955