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