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