fs/overlayfs/overlayfs.h

   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;