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