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