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