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