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 }; 44 45 /* 46 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 47 * where: 48 * origin.fh - exported file handle of the lower file 49 * origin.uuid - uuid of the lower filesystem 50 */ 51 #define OVL_FH_VERSION 0 52 #define OVL_FH_MAGIC 0xfb 53 54 /* CPU byte order required for fid decoding: */ 55 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 56 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 57 /* Is the real inode encoded in fid an upper inode? */ 58 #define OVL_FH_FLAG_PATH_UPPER (1 << 2) 59 60 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 61 OVL_FH_FLAG_PATH_UPPER) 62 63 #if defined(__LITTLE_ENDIAN) 64 #define OVL_FH_FLAG_CPU_ENDIAN 0 65 #elif defined(__BIG_ENDIAN) 66 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 67 #else 68 #error Endianness not defined 69 #endif 70 71 /* The type returned by overlay exportfs ops when encoding an ovl_fh handle */ 72 #define OVL_FILEID 0xfb 73 74 /* On-disk and in-memeory format for redirect by file handle */ 75 struct ovl_fh { 76 u8 version; /* 0 */ 77 u8 magic; /* 0xfb */ 78 u8 len; /* size of this header + size of fid */ 79 u8 flags; /* OVL_FH_FLAG_* */ 80 u8 type; /* fid_type of fid */ 81 uuid_t uuid; /* uuid of filesystem */ 82 u8 fid[0]; /* file identifier */ 83 } __packed; 84 85 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 86 { 87 int err = vfs_rmdir(dir, dentry); 88 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 89 return err; 90 } 91 92 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 93 { 94 int err = vfs_unlink(dir, dentry, NULL); 95 pr_debug("unlink(%pd2) = %i\n", dentry, err); 96 return err; 97 } 98 99 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 100 struct dentry *new_dentry, bool debug) 101 { 102 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 103 if (debug) { 104 pr_debug("link(%pd2, %pd2) = %i\n", 105 old_dentry, new_dentry, err); 106 } 107 return err; 108 } 109 110 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 111 umode_t mode, bool debug) 112 { 113 int err = vfs_create(dir, dentry, mode, true); 114 if (debug) 115 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 116 return err; 117 } 118 119 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 120 umode_t mode, bool debug) 121 { 122 int err = vfs_mkdir(dir, dentry, mode); 123 if (debug) 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, bool debug) 130 { 131 int err = vfs_mknod(dir, dentry, mode, dev); 132 if (debug) { 133 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", 134 dentry, mode, dev, err); 135 } 136 return err; 137 } 138 139 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 140 const char *oldname, bool debug) 141 { 142 int err = vfs_symlink(dir, dentry, oldname); 143 if (debug) 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\", \"%*s\", 0x%x) = %i\n", 153 dentry, name, (int) size, (char *) value, 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", 171 olddentry, newdentry, flags); 172 173 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 174 175 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 /* util.c */ 199 int ovl_want_write(struct dentry *dentry); 200 void ovl_drop_write(struct dentry *dentry); 201 struct dentry *ovl_workdir(struct dentry *dentry); 202 const struct cred *ovl_override_creds(struct super_block *sb); 203 struct super_block *ovl_same_sb(struct super_block *sb); 204 bool ovl_can_decode_fh(struct super_block *sb); 205 struct dentry *ovl_indexdir(struct super_block *sb); 206 bool ovl_index_all(struct super_block *sb); 207 bool ovl_verify_lower(struct super_block *sb); 208 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 209 bool ovl_dentry_remote(struct dentry *dentry); 210 bool ovl_dentry_weird(struct dentry *dentry); 211 enum ovl_path_type ovl_path_type(struct dentry *dentry); 212 void ovl_path_upper(struct dentry *dentry, struct path *path); 213 void ovl_path_lower(struct dentry *dentry, struct path *path); 214 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 215 struct dentry *ovl_dentry_upper(struct dentry *dentry); 216 struct dentry *ovl_dentry_lower(struct dentry *dentry); 217 struct dentry *ovl_dentry_real(struct dentry *dentry); 218 struct dentry *ovl_i_dentry_upper(struct inode *inode); 219 struct inode *ovl_inode_upper(struct inode *inode); 220 struct inode *ovl_inode_lower(struct inode *inode); 221 struct inode *ovl_inode_real(struct inode *inode); 222 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 223 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 224 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 225 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 226 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 227 bool ovl_dentry_is_opaque(struct dentry *dentry); 228 bool ovl_dentry_is_whiteout(struct dentry *dentry); 229 void ovl_dentry_set_opaque(struct dentry *dentry); 230 bool ovl_dentry_has_upper_alias(struct dentry *dentry); 231 void ovl_dentry_set_upper_alias(struct dentry *dentry); 232 bool ovl_redirect_dir(struct super_block *sb); 233 const char *ovl_dentry_get_redirect(struct dentry *dentry); 234 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 235 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, 236 struct dentry *lowerdentry); 237 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 238 void ovl_dentry_version_inc(struct dentry *dentry, bool impurity); 239 u64 ovl_dentry_version_get(struct dentry *dentry); 240 bool ovl_is_whiteout(struct dentry *dentry); 241 struct file *ovl_path_open(struct path *path, int flags); 242 int ovl_copy_up_start(struct dentry *dentry); 243 void ovl_copy_up_end(struct dentry *dentry); 244 bool ovl_check_origin_xattr(struct dentry *dentry); 245 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name); 246 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 247 const char *name, const void *value, size_t size, 248 int xerr); 249 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 250 void ovl_set_flag(unsigned long flag, struct inode *inode); 251 void ovl_clear_flag(unsigned long flag, struct inode *inode); 252 bool ovl_test_flag(unsigned long flag, struct inode *inode); 253 bool ovl_inuse_trylock(struct dentry *dentry); 254 void ovl_inuse_unlock(struct dentry *dentry); 255 bool ovl_need_index(struct dentry *dentry); 256 int ovl_nlink_start(struct dentry *dentry, bool *locked); 257 void ovl_nlink_end(struct dentry *dentry, bool locked); 258 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 259 260 static inline bool ovl_is_impuredir(struct dentry *dentry) 261 { 262 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE); 263 } 264 265 266 /* namei.c */ 267 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len); 268 struct dentry *ovl_decode_fh(struct ovl_fh *fh, struct vfsmount *mnt); 269 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, 270 struct dentry *upperdentry, struct ovl_path **stackp); 271 int ovl_verify_set_fh(struct dentry *dentry, const char *name, 272 struct dentry *real, bool is_upper, bool set); 273 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); 274 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 275 int ovl_get_index_name(struct dentry *origin, struct qstr *name); 276 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 277 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 278 struct dentry *origin, bool verify); 279 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 280 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 281 unsigned int flags); 282 bool ovl_lower_positive(struct dentry *dentry); 283 284 static inline int ovl_verify_origin(struct dentry *upper, 285 struct dentry *origin, bool set) 286 { 287 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set); 288 } 289 290 static inline int ovl_verify_upper(struct dentry *index, 291 struct dentry *upper, bool set) 292 { 293 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set); 294 } 295 296 /* readdir.c */ 297 extern const struct file_operations ovl_dir_operations; 298 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 299 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 300 void ovl_cache_free(struct list_head *list); 301 void ovl_dir_cache_free(struct inode *inode); 302 int ovl_check_d_type_supported(struct path *realpath); 303 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 304 struct dentry *dentry, int level); 305 int ovl_indexdir_cleanup(struct ovl_fs *ofs); 306 307 /* inode.c */ 308 int ovl_set_nlink_upper(struct dentry *dentry); 309 int ovl_set_nlink_lower(struct dentry *dentry); 310 unsigned int ovl_get_nlink(struct dentry *lowerdentry, 311 struct dentry *upperdentry, 312 unsigned int fallback); 313 int ovl_setattr(struct dentry *dentry, struct iattr *attr); 314 int ovl_getattr(const struct path *path, struct kstat *stat, 315 u32 request_mask, unsigned int flags); 316 int ovl_permission(struct inode *inode, int mask); 317 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 318 const void *value, size_t size, int flags); 319 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 320 void *value, size_t size); 321 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 322 struct posix_acl *ovl_get_acl(struct inode *inode, int type); 323 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); 324 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags); 325 bool ovl_is_private_xattr(const char *name); 326 327 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 328 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 329 bool is_upper); 330 struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, 331 struct dentry *lowerdentry, struct dentry *index, 332 unsigned int numlower); 333 static inline void ovl_copyattr(struct inode *from, struct inode *to) 334 { 335 to->i_uid = from->i_uid; 336 to->i_gid = from->i_gid; 337 to->i_mode = from->i_mode; 338 to->i_atime = from->i_atime; 339 to->i_mtime = from->i_mtime; 340 to->i_ctime = from->i_ctime; 341 } 342 343 /* dir.c */ 344 extern const struct inode_operations ovl_dir_inode_operations; 345 struct dentry *ovl_lookup_temp(struct dentry *workdir); 346 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir, 347 struct dentry *dentry); 348 struct cattr { 349 dev_t rdev; 350 umode_t mode; 351 const char *link; 352 }; 353 int ovl_create_real(struct inode *dir, struct dentry *newdentry, 354 struct cattr *attr, 355 struct dentry *hardlink, bool debug); 356 int ovl_cleanup(struct inode *dir, struct dentry *dentry); 357 358 /* copy_up.c */ 359 int ovl_copy_up(struct dentry *dentry); 360 int ovl_copy_up_flags(struct dentry *dentry, int flags); 361 int ovl_copy_xattr(struct dentry *old, struct dentry *new); 362 int ovl_set_attr(struct dentry *upper, struct kstat *stat); 363 struct ovl_fh *ovl_encode_fh(struct dentry *real, bool is_upper); 364 int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 365 struct dentry *upper); 366 367 /* export.c */ 368 extern const struct export_operations ovl_export_operations; 369