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 "ovl_entry.h" 11 12 #undef pr_fmt 13 #define pr_fmt(fmt) "overlayfs: " fmt 14 15 enum ovl_path_type { 16 __OVL_PATH_UPPER = (1 << 0), 17 __OVL_PATH_MERGE = (1 << 1), 18 __OVL_PATH_ORIGIN = (1 << 2), 19 }; 20 21 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 22 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 23 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 24 25 #define OVL_XATTR_NAMESPACE "overlay." 26 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE 27 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE 28 29 enum ovl_xattr { 30 OVL_XATTR_OPAQUE, 31 OVL_XATTR_REDIRECT, 32 OVL_XATTR_ORIGIN, 33 OVL_XATTR_IMPURE, 34 OVL_XATTR_NLINK, 35 OVL_XATTR_UPPER, 36 OVL_XATTR_METACOPY, 37 }; 38 39 enum ovl_inode_flag { 40 /* Pure upper dir that may contain non pure upper entries */ 41 OVL_IMPURE, 42 /* Non-merge dir that may contain whiteout entries */ 43 OVL_WHITEOUTS, 44 OVL_INDEX, 45 OVL_UPPERDATA, 46 /* Inode number will remain constant over copy up. */ 47 OVL_CONST_INO, 48 }; 49 50 enum ovl_entry_flag { 51 OVL_E_UPPER_ALIAS, 52 OVL_E_OPAQUE, 53 OVL_E_CONNECTED, 54 }; 55 56 enum { 57 OVL_XINO_OFF, 58 OVL_XINO_AUTO, 59 OVL_XINO_ON, 60 }; 61 62 /* 63 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 64 * where: 65 * origin.fh - exported file handle of the lower file 66 * origin.uuid - uuid of the lower filesystem 67 */ 68 #define OVL_FH_VERSION 0 69 #define OVL_FH_MAGIC 0xfb 70 71 /* CPU byte order required for fid decoding: */ 72 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 73 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 74 /* Is the real inode encoded in fid an upper inode? */ 75 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 76 77 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 78 OVL_FH_FLAG_PATH_UPPER) 79 80 #if defined(__LITTLE_ENDIAN) 81 #define OVL_FH_FLAG_CPU_ENDIAN 0 82 #elif defined(__BIG_ENDIAN) 83 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 84 #else 85 #error Endianness not defined 86 #endif 87 88 /* The type used to be returned by overlay exportfs for misaligned fid */ 89 #define OVL_FILEID_V0 0xfb 90 /* The type returned by overlay exportfs for 32bit aligned fid */ 91 #define OVL_FILEID_V1 0xf8 92 93 /* On-disk format for "origin" file handle */ 94 struct ovl_fb { 95 u8 version; /* 0 */ 96 u8 magic; /* 0xfb */ 97 u8 len; /* size of this header + size of fid */ 98 u8 flags; /* OVL_FH_FLAG_* */ 99 u8 type; /* fid_type of fid */ 100 uuid_t uuid; /* uuid of filesystem */ 101 u32 fid[]; /* file identifier should be 32bit aligned in-memory */ 102 } __packed; 103 104 /* In-memory and on-wire format for overlay file handle */ 105 struct ovl_fh { 106 u8 padding[3]; /* make sure fb.fid is 32bit aligned */ 107 union { 108 struct ovl_fb fb; 109 u8 buf[0]; 110 }; 111 } __packed; 112 113 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) 114 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) 115 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ 116 offsetof(struct ovl_fb, fid)) 117 118 extern const char *const ovl_xattr_table[][2]; 119 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) 120 { 121 return ovl_xattr_table[ox][ofs->config.userxattr]; 122 } 123 124 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 125 { 126 int err = vfs_rmdir(dir, dentry); 127 128 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 129 return err; 130 } 131 132 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 133 { 134 int err = vfs_unlink(dir, dentry, NULL); 135 136 pr_debug("unlink(%pd2) = %i\n", dentry, err); 137 return err; 138 } 139 140 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 141 struct dentry *new_dentry) 142 { 143 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 144 145 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 146 return err; 147 } 148 149 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 150 umode_t mode) 151 { 152 int err = vfs_create(dir, dentry, mode, true); 153 154 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 155 return err; 156 } 157 158 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 159 umode_t mode) 160 { 161 int err = vfs_mkdir(dir, dentry, mode); 162 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 163 return err; 164 } 165 166 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, 167 umode_t mode, dev_t dev) 168 { 169 int err = vfs_mknod(dir, dentry, mode, dev); 170 171 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 172 return err; 173 } 174 175 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 176 const char *oldname) 177 { 178 int err = vfs_symlink(dir, dentry, oldname); 179 180 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 181 return err; 182 } 183 184 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry, 185 enum ovl_xattr ox, void *value, 186 size_t size) 187 { 188 const char *name = ovl_xattr(ofs, ox); 189 return vfs_getxattr(dentry, name, value, size); 190 } 191 192 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 193 enum ovl_xattr ox, const void *value, 194 size_t size) 195 { 196 const char *name = ovl_xattr(ofs, ox); 197 int err = vfs_setxattr(dentry, name, value, size, 0); 198 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", 199 dentry, name, min((int)size, 48), value, size, err); 200 return err; 201 } 202 203 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 204 enum ovl_xattr ox) 205 { 206 const char *name = ovl_xattr(ofs, ox); 207 int err = vfs_removexattr(dentry, name); 208 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 209 return err; 210 } 211 212 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, 213 struct inode *newdir, struct dentry *newdentry, 214 unsigned int flags) 215 { 216 int err; 217 218 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); 219 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 220 if (err) { 221 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 222 olddentry, newdentry, err); 223 } 224 return err; 225 } 226 227 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) 228 { 229 int err = vfs_whiteout(dir, dentry); 230 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 231 return err; 232 } 233 234 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) 235 { 236 struct dentry *ret = vfs_tmpfile(dentry, mode, 0); 237 int err = PTR_ERR_OR_ZERO(ret); 238 239 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 240 return ret; 241 } 242 243 static inline bool ovl_open_flags_need_copy_up(int flags) 244 { 245 if (!flags) 246 return false; 247 248 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 249 } 250 251 /* util.c */ 252 int ovl_want_write(struct dentry *dentry); 253 void ovl_drop_write(struct dentry *dentry); 254 struct dentry *ovl_workdir(struct dentry *dentry); 255 const struct cred *ovl_override_creds(struct super_block *sb); 256 int ovl_can_decode_fh(struct super_block *sb); 257 struct dentry *ovl_indexdir(struct super_block *sb); 258 bool ovl_index_all(struct super_block *sb); 259 bool ovl_verify_lower(struct super_block *sb); 260 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 261 bool ovl_dentry_remote(struct dentry *dentry); 262 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry, 263 unsigned int mask); 264 bool ovl_dentry_weird(struct dentry *dentry); 265 enum ovl_path_type ovl_path_type(struct dentry *dentry); 266 void ovl_path_upper(struct dentry *dentry, struct path *path); 267 void ovl_path_lower(struct dentry *dentry, struct path *path); 268 void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 269 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 270 struct dentry *ovl_dentry_upper(struct dentry *dentry); 271 struct dentry *ovl_dentry_lower(struct dentry *dentry); 272 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 273 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 274 struct dentry *ovl_dentry_real(struct dentry *dentry); 275 struct dentry *ovl_i_dentry_upper(struct inode *inode); 276 struct inode *ovl_inode_upper(struct inode *inode); 277 struct inode *ovl_inode_lower(struct inode *inode); 278 struct inode *ovl_inode_lowerdata(struct inode *inode); 279 struct inode *ovl_inode_real(struct inode *inode); 280 struct inode *ovl_inode_realdata(struct inode *inode); 281 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 282 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 283 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 284 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 285 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 286 bool ovl_dentry_is_opaque(struct dentry *dentry); 287 bool ovl_dentry_is_whiteout(struct dentry *dentry); 288 void ovl_dentry_set_opaque(struct dentry *dentry); 289 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 290 void ovl_dentry_set_upper_alias(struct dentry *dentry); 291 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 292 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 293 bool ovl_has_upperdata(struct inode *inode); 294 void ovl_set_upperdata(struct inode *inode); 295 bool ovl_redirect_dir(struct super_block *sb); 296 const char *ovl_dentry_get_redirect(struct dentry *dentry); 297 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 298 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 299 void ovl_dir_modified(struct dentry *dentry, bool impurity); 300 u64 ovl_dentry_version_get(struct dentry *dentry); 301 bool ovl_is_whiteout(struct dentry *dentry); 302 struct file *ovl_path_open(struct path *path, int flags); 303 int ovl_copy_up_start(struct dentry *dentry, int flags); 304 void ovl_copy_up_end(struct dentry *dentry); 305 bool ovl_already_copied_up(struct dentry *dentry, int flags); 306 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry); 307 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry, 308 enum ovl_xattr ox); 309 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 310 enum ovl_xattr ox, const void *value, size_t size, 311 int xerr); 312 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 313 void ovl_set_flag(unsigned long flag, struct inode *inode); 314 void ovl_clear_flag(unsigned long flag, struct inode *inode); 315 bool ovl_test_flag(unsigned long flag, struct inode *inode); 316 bool ovl_inuse_trylock(struct dentry *dentry); 317 void ovl_inuse_unlock(struct dentry *dentry); 318 bool ovl_is_inuse(struct dentry *dentry); 319 bool ovl_need_index(struct dentry *dentry); 320 int ovl_nlink_start(struct dentry *dentry); 321 void ovl_nlink_end(struct dentry *dentry); 322 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 323 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry); 324 bool ovl_is_metacopy_dentry(struct dentry *dentry); 325 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry, 326 int padding); 327 int ovl_sync_status(struct ovl_fs *ofs); 328 329 static inline bool ovl_is_impuredir(struct super_block *sb, 330 struct dentry *dentry) 331 { 332 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE); 333 } 334 335 /* 336 * With xino=auto, we do best effort to keep all inodes on same st_dev and 337 * d_ino consistent with st_ino. 338 * With xino=on, we do the same effort but we warn if we failed. 339 */ 340 static inline bool ovl_xino_warn(struct super_block *sb) 341 { 342 return OVL_FS(sb)->config.xino == OVL_XINO_ON; 343 } 344 345 /* All layers on same fs? */ 346 static inline bool ovl_same_fs(struct super_block *sb) 347 { 348 return OVL_FS(sb)->xino_mode == 0; 349 } 350 351 /* All overlay inodes have same st_dev? */ 352 static inline bool ovl_same_dev(struct super_block *sb) 353 { 354 return OVL_FS(sb)->xino_mode >= 0; 355 } 356 357 static inline unsigned int ovl_xino_bits(struct super_block *sb) 358 { 359 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0; 360 } 361 362 static inline void ovl_inode_lock(struct inode *inode) 363 { 364 mutex_lock(&OVL_I(inode)->lock); 365 } 366 367 static inline int ovl_inode_lock_interruptible(struct inode *inode) 368 { 369 return mutex_lock_interruptible(&OVL_I(inode)->lock); 370 } 371 372 static inline void ovl_inode_unlock(struct inode *inode) 373 { 374 mutex_unlock(&OVL_I(inode)->lock); 375 } 376 377 378 /* namei.c */ 379 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); 380 381 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) 382 { 383 if (fh_len < sizeof(struct ovl_fh)) 384 return -EINVAL; 385 386 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); 387 } 388 389 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, 390 struct vfsmount *mnt, bool connected); 391 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 392 struct dentry *upperdentry, struct ovl_path **stackp); 393 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, 394 enum ovl_xattr ox, struct dentry *real, bool is_upper, 395 bool set); 396 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); 397 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 398 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin, 399 struct qstr *name); 400 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 401 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 402 struct dentry *origin, bool verify); 403 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 404 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 405 unsigned int flags); 406 bool ovl_lower_positive(struct dentry *dentry); 407 408 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, 409 struct dentry *origin, bool set) 410 { 411 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, 412 false, set); 413 } 414 415 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, 416 struct dentry *upper, bool set) 417 { 418 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); 419 } 420 421 /* readdir.c */ 422 extern const struct file_operations ovl_dir_operations; 423 struct file *ovl_dir_real_file(const struct file *file, bool want_upper); 424 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 425 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 426 void ovl_cache_free(struct list_head *list); 427 void ovl_dir_cache_free(struct inode *inode); 428 int ovl_check_d_type_supported(struct path *realpath); 429 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 430 struct dentry *dentry, int level); 431 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 432 433 /* inode.c */ 434 int ovl_set_nlink_upper(struct dentry *dentry); 435 int ovl_set_nlink_lower(struct dentry *dentry); 436 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 437 struct dentry *upperdentry, 438 unsigned int fallback); 439 int ovl_setattr(struct dentry *dentry, struct iattr *attr); 440 int ovl_getattr(const struct path *path, struct kstat *stat, 441 u32 request_mask, unsigned int flags); 442 int ovl_permission(struct inode *inode, int mask); 443 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 444 const void *value, size_t size, int flags); 445 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 446 void *value, size_t size); 447 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 448 struct posix_acl *ovl_get_acl(struct inode *inode, int type); 449 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags); 450 bool ovl_is_private_xattr(struct super_block *sb, const char *name); 451 452 struct ovl_inode_params { 453 struct inode *newinode; 454 struct dentry *upperdentry; 455 struct ovl_path *lowerpath; 456 bool index; 457 unsigned int numlower; 458 char *redirect; 459 struct dentry *lowerdata; 460 }; 461 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 462 unsigned long ino, int fsid); 463 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 464 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 465 bool is_upper); 466 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); 467 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); 468 struct inode *ovl_get_inode(struct super_block *sb, 469 struct ovl_inode_params *oip); 470 static inline void ovl_copyattr(struct inode *from, struct inode *to) 471 { 472 to->i_uid = from->i_uid; 473 to->i_gid = from->i_gid; 474 to->i_mode = from->i_mode; 475 to->i_atime = from->i_atime; 476 to->i_mtime = from->i_mtime; 477 to->i_ctime = from->i_ctime; 478 i_size_write(to, i_size_read(from)); 479 } 480 481 static inline void ovl_copyflags(struct inode *from, struct inode *to) 482 { 483 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME; 484 485 inode_set_flags(to, from->i_flags & mask, mask); 486 } 487 488 /* dir.c */ 489 extern const struct inode_operations ovl_dir_inode_operations; 490 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, 491 struct dentry *dentry); 492 struct ovl_cattr { 493 dev_t rdev; 494 umode_t mode; 495 const char *link; 496 struct dentry *hardlink; 497 }; 498 499 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 500 501 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, 502 struct ovl_cattr *attr); 503 int ovl_cleanup(struct inode *dir, struct dentry *dentry); 504 struct dentry *ovl_lookup_temp(struct dentry *workdir); 505 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr); 506 507 /* file.c */ 508 extern const struct file_operations ovl_file_operations; 509 int __init ovl_aio_request_cache_init(void); 510 void ovl_aio_request_cache_destroy(void); 511 long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 512 long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 513 514 /* copy_up.c */ 515 int ovl_copy_up(struct dentry *dentry); 516 int ovl_copy_up_with_data(struct dentry *dentry); 517 int ovl_maybe_copy_up(struct dentry *dentry, int flags); 518 int ovl_copy_xattr(struct super_block *sb, struct dentry *old, 519 struct dentry *new); 520 int ovl_set_attr(struct dentry *upper, struct kstat *stat); 521 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, 522 bool is_upper); 523 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *dentry, 524 struct dentry *lower, struct dentry *upper); 525 526 /* export.c */ 527 extern const struct export_operations ovl_export_operations; 528