1 /* 2 * 3 * Copyright (C) 2011 Novell Inc. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 as published by 7 * the Free Software Foundation. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/uuid.h> 12 #include <linux/fs.h> 13 #include "ovl_entry.h" 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 returned by overlay exportfs ops when encoding an ovl_fh handle */ 78 #define OVL_FILEID 0xfb 79 80 /* On-disk and in-memeory format for redirect by file handle */ 81 struct ovl_fh { 82 u8 version; /* 0 */ 83 u8 magic; /* 0xfb */ 84 u8 len; /* size of this header + size of fid */ 85 u8 flags; /* OVL_FH_FLAG_* */ 86 u8 type; /* fid_type of fid */ 87 uuid_t uuid; /* uuid of filesystem */ 88 u8 fid[0]; /* file identifier */ 89 } __packed; 90 91 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 92 { 93 int err = vfs_rmdir(dir, dentry); 94 95 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 96 return err; 97 } 98 99 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 100 { 101 int err = vfs_unlink(dir, dentry, NULL); 102 103 pr_debug("unlink(%pd2) = %i\n", dentry, err); 104 return err; 105 } 106 107 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 108 struct dentry *new_dentry) 109 { 110 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 111 112 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 113 return err; 114 } 115 116 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 117 umode_t mode) 118 { 119 int err = vfs_create(dir, dentry, mode, true); 120 121 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 122 return err; 123 } 124 125 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 126 umode_t mode) 127 { 128 int err = vfs_mkdir(dir, dentry, mode); 129 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 130 return err; 131 } 132 133 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, 134 umode_t mode, dev_t dev) 135 { 136 int err = vfs_mknod(dir, dentry, mode, dev); 137 138 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 139 return err; 140 } 141 142 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 143 const char *oldname) 144 { 145 int err = vfs_symlink(dir, dentry, oldname); 146 147 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 148 return err; 149 } 150 151 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name, 152 const void *value, size_t size, int flags) 153 { 154 int err = vfs_setxattr(dentry, name, value, size, flags); 155 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n", 156 dentry, name, min((int)size, 48), value, size, flags, err); 157 return err; 158 } 159 160 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name) 161 { 162 int err = vfs_removexattr(dentry, name); 163 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 164 return err; 165 } 166 167 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, 168 struct inode *newdir, struct dentry *newdentry, 169 unsigned int flags) 170 { 171 int err; 172 173 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); 174 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 175 if (err) { 176 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 177 olddentry, newdentry, err); 178 } 179 return err; 180 } 181 182 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) 183 { 184 int err = vfs_whiteout(dir, dentry); 185 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 186 return err; 187 } 188 189 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) 190 { 191 struct dentry *ret = vfs_tmpfile(dentry, mode, 0); 192 int err = PTR_ERR_OR_ZERO(ret); 193 194 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 195 return ret; 196 } 197 198 static inline bool ovl_open_flags_need_copy_up(int flags) 199 { 200 if (!flags) 201 return false; 202 203 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 204 } 205 206 /* util.c */ 207 int ovl_want_write(struct dentry *dentry); 208 void ovl_drop_write(struct dentry *dentry); 209 struct dentry *ovl_workdir(struct dentry *dentry); 210 const struct cred *ovl_override_creds(struct super_block *sb); 211 struct super_block *ovl_same_sb(struct super_block *sb); 212 int ovl_can_decode_fh(struct super_block *sb); 213 struct dentry *ovl_indexdir(struct super_block *sb); 214 bool ovl_index_all(struct super_block *sb); 215 bool ovl_verify_lower(struct super_block *sb); 216 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 217 bool ovl_dentry_remote(struct dentry *dentry); 218 bool ovl_dentry_weird(struct dentry *dentry); 219 enum ovl_path_type ovl_path_type(struct dentry *dentry); 220 void ovl_path_upper(struct dentry *dentry, struct path *path); 221 void ovl_path_lower(struct dentry *dentry, struct path *path); 222 void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 223 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 224 struct dentry *ovl_dentry_upper(struct dentry *dentry); 225 struct dentry *ovl_dentry_lower(struct dentry *dentry); 226 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 227 struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 228 struct dentry *ovl_dentry_real(struct dentry *dentry); 229 struct dentry *ovl_i_dentry_upper(struct inode *inode); 230 struct inode *ovl_inode_upper(struct inode *inode); 231 struct inode *ovl_inode_lower(struct inode *inode); 232 struct inode *ovl_inode_lowerdata(struct inode *inode); 233 struct inode *ovl_inode_real(struct inode *inode); 234 struct inode *ovl_inode_realdata(struct inode *inode); 235 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 236 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 237 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 238 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 239 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 240 bool ovl_dentry_is_opaque(struct dentry *dentry); 241 bool ovl_dentry_is_whiteout(struct dentry *dentry); 242 void ovl_dentry_set_opaque(struct dentry *dentry); 243 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 244 void ovl_dentry_set_upper_alias(struct dentry *dentry); 245 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 246 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 247 bool ovl_has_upperdata(struct inode *inode); 248 void ovl_set_upperdata(struct inode *inode); 249 bool ovl_redirect_dir(struct super_block *sb); 250 const char *ovl_dentry_get_redirect(struct dentry *dentry); 251 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 252 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, 253 struct dentry *lowerdentry, struct dentry *lowerdata); 254 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 255 void ovl_dir_modified(struct dentry *dentry, bool impurity); 256 u64 ovl_dentry_version_get(struct dentry *dentry); 257 bool ovl_is_whiteout(struct dentry *dentry); 258 struct file *ovl_path_open(struct path *path, int flags); 259 int ovl_copy_up_start(struct dentry *dentry, int flags); 260 void ovl_copy_up_end(struct dentry *dentry); 261 bool ovl_already_copied_up(struct dentry *dentry, int flags); 262 bool ovl_check_origin_xattr(struct dentry *dentry); 263 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name); 264 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 265 const char *name, const void *value, size_t size, 266 int xerr); 267 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 268 void ovl_set_flag(unsigned long flag, struct inode *inode); 269 void ovl_clear_flag(unsigned long flag, struct inode *inode); 270 bool ovl_test_flag(unsigned long flag, struct inode *inode); 271 bool ovl_inuse_trylock(struct dentry *dentry); 272 void ovl_inuse_unlock(struct dentry *dentry); 273 bool ovl_need_index(struct dentry *dentry); 274 int ovl_nlink_start(struct dentry *dentry, bool *locked); 275 void ovl_nlink_end(struct dentry *dentry, bool locked); 276 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 277 int ovl_check_metacopy_xattr(struct dentry *dentry); 278 bool ovl_is_metacopy_dentry(struct dentry *dentry); 279 char *ovl_get_redirect_xattr(struct dentry *dentry, int 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 } 292 293 294 /* namei.c */ 295 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len); 296 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, 297 bool connected); 298 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 299 struct dentry *upperdentry, struct ovl_path **stackp); 300 int ovl_verify_set_fh(struct dentry *dentry, const char *name, 301 struct dentry *real, bool is_upper, bool set); 302 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); 303 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 304 int ovl_get_index_name(struct dentry *origin, struct qstr *name); 305 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 306 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 307 struct dentry *origin, bool verify); 308 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 309 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 310 unsigned int flags); 311 bool ovl_lower_positive(struct dentry *dentry); 312 313 static inline int ovl_verify_origin(struct dentry *upper, 314 struct dentry *origin, bool set) 315 { 316 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set); 317 } 318 319 static inline int ovl_verify_upper(struct dentry *index, 320 struct dentry *upper, bool set) 321 { 322 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set); 323 } 324 325 /* readdir.c */ 326 extern const struct file_operations ovl_dir_operations; 327 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 328 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 329 void ovl_cache_free(struct list_head *list); 330 void ovl_dir_cache_free(struct inode *inode); 331 int ovl_check_d_type_supported(struct path *realpath); 332 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 333 struct dentry *dentry, int level); 334 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 335 336 /* inode.c */ 337 int ovl_set_nlink_upper(struct dentry *dentry); 338 int ovl_set_nlink_lower(struct dentry *dentry); 339 unsigned int ovl_get_nlink(struct dentry *lowerdentry, 340 struct dentry *upperdentry, 341 unsigned int fallback); 342 int ovl_setattr(struct dentry *dentry, struct iattr *attr); 343 int ovl_getattr(const struct path *path, struct kstat *stat, 344 u32 request_mask, unsigned int flags); 345 int ovl_permission(struct inode *inode, int mask); 346 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 347 const void *value, size_t size, int flags); 348 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 349 void *value, size_t size); 350 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 351 struct posix_acl *ovl_get_acl(struct inode *inode, int type); 352 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags); 353 bool ovl_is_private_xattr(const char *name); 354 355 struct ovl_inode_params { 356 struct inode *newinode; 357 struct dentry *upperdentry; 358 struct ovl_path *lowerpath; 359 struct dentry *index; 360 unsigned int numlower; 361 char *redirect; 362 struct dentry *lowerdata; 363 }; 364 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 365 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 366 bool is_upper); 367 struct inode *ovl_get_inode(struct super_block *sb, 368 struct ovl_inode_params *oip); 369 static inline void ovl_copyattr(struct inode *from, struct inode *to) 370 { 371 to->i_uid = from->i_uid; 372 to->i_gid = from->i_gid; 373 to->i_mode = from->i_mode; 374 to->i_atime = from->i_atime; 375 to->i_mtime = from->i_mtime; 376 to->i_ctime = from->i_ctime; 377 i_size_write(to, i_size_read(from)); 378 } 379 380 static inline void ovl_copyflags(struct inode *from, struct inode *to) 381 { 382 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME; 383 384 inode_set_flags(to, from->i_flags & mask, mask); 385 } 386 387 /* dir.c */ 388 extern const struct inode_operations ovl_dir_inode_operations; 389 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir, 390 struct dentry *dentry); 391 struct ovl_cattr { 392 dev_t rdev; 393 umode_t mode; 394 const char *link; 395 struct dentry *hardlink; 396 }; 397 398 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 399 400 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, 401 struct ovl_cattr *attr); 402 int ovl_cleanup(struct inode *dir, struct dentry *dentry); 403 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr); 404 405 /* file.c */ 406 extern const struct file_operations ovl_file_operations; 407 408 /* copy_up.c */ 409 int ovl_copy_up(struct dentry *dentry); 410 int ovl_copy_up_with_data(struct dentry *dentry); 411 int ovl_copy_up_flags(struct dentry *dentry, int flags); 412 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); 413 int ovl_copy_xattr(struct dentry *old, struct dentry *new); 414 int ovl_set_attr(struct dentry *upper, struct kstat *stat); 415 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); 416 int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 417 struct dentry *upper); 418 419 /* export.c */ 420 extern const struct export_operations ovl_export_operations; 421