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