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