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         OVL_E_CONNECTED,
  44 };
  45
  46 /*
  47  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
  48  * where:
  49  * origin.fh    - exported file handle of the lower file
  50  * origin.uuid  - uuid of the lower filesystem
  51  */
  52 #define OVL_FH_VERSION  0
  53 #define OVL_FH_MAGIC    0xfb
  54
  55 /* CPU byte order required for fid decoding:  */
  56 #define OVL_FH_FLAG_BIG_ENDIAN  (1 << 0)
  57 #define OVL_FH_FLAG_ANY_ENDIAN  (1 << 1)
  58 /* Is the real inode encoded in fid an upper inode? */
  59 #define OVL_FH_FLAG_PATH_UPPER  (1 << 2)
  60
  61 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
  62                          OVL_FH_FLAG_PATH_UPPER)
  63
  64 #if defined(__LITTLE_ENDIAN)
  65 #define OVL_FH_FLAG_CPU_ENDIAN 0
  66 #elif defined(__BIG_ENDIAN)
  67 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
  68 #else
  69 #error Endianness not defined
  70 #endif
  71
  72 /* The type returned by overlay exportfs ops when encoding an ovl_fh handle */
  73 #define OVL_FILEID      0xfb
  74
  75 /* On-disk and in-memeory format for redirect by file handle */
  76 struct ovl_fh {
  77         u8 version;     /* 0 */
  78         u8 magic;       /* 0xfb */
  79         u8 len;         /* size of this header + size of fid */
  80         u8 flags;       /* OVL_FH_FLAG_* */
  81         u8 type;        /* fid_type of fid */
  82         uuid_t uuid;    /* uuid of filesystem */
  83         u8 fid[0];      /* file identifier */
  84 } __packed;
  85
  86 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
  87 {
  88         int err = vfs_rmdir(dir, dentry);
  89
  90         pr_debug("rmdir(%pd2) = %i\n", dentry, err);
  91         return err;
  92 }
  93
  94 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
  95 {
  96         int err = vfs_unlink(dir, dentry, NULL);
  97
  98         pr_debug("unlink(%pd2) = %i\n", dentry, err);
  99         return err;
 100 }
 101
 102 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
 103                               struct dentry *new_dentry)
 104 {
 105         int err = vfs_link(old_dentry, dir, new_dentry, NULL);
 106
 107         pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
 108         return err;
 109 }
 110
 111 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
 112                                 umode_t mode)
 113 {
 114         int err = vfs_create(dir, dentry, mode, true);
 115
 116         pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
 117         return err;
 118 }
 119
 120 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
 121                                umode_t mode)
 122 {
 123         int err = vfs_mkdir(dir, dentry, mode);
 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)
 130 {
 131         int err = vfs_mknod(dir, dentry, mode, dev);
 132
 133         pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
 134         return err;
 135 }
 136
 137 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 138                                  const char *oldname)
 139 {
 140         int err = vfs_symlink(dir, dentry, oldname);
 141
 142         pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
 143         return err;
 144 }
 145
 146 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 147                                   const void *value, size_t size, int flags)
 148 {
 149         int err = vfs_setxattr(dentry, name, value, size, flags);
 150         pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
 151                  dentry, name, (int) size, (char *) value, flags, err);
 152         return err;
 153 }
 154
 155 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
 156 {
 157         int err = vfs_removexattr(dentry, name);
 158         pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 159         return err;
 160 }
 161
 162 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
 163                                 struct inode *newdir, struct dentry *newdentry,
 164                                 unsigned int flags)
 165 {
 166         int err;
 167
 168         pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
 169         err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
 170         if (err) {
 171                 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
 172                          olddentry, newdentry, err);
 173         }
 174         return err;
 175 }
 176
 177 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
 178 {
 179         int err = vfs_whiteout(dir, dentry);
 180         pr_debug("whiteout(%pd2) = %i\n", dentry, err);
 181         return err;
 182 }
 183
 184 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
 185 {
 186         struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
 187         int err = PTR_ERR_OR_ZERO(ret);
 188
 189         pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
 190         return ret;
 191 }
 192
 193 /* util.c */
 194 int ovl_want_write(struct dentry *dentry);
 195 void ovl_drop_write(struct dentry *dentry);
 196 struct dentry *ovl_workdir(struct dentry *dentry);
 197 const struct cred *ovl_override_creds(struct super_block *sb);
 198 struct super_block *ovl_same_sb(struct super_block *sb);
 199 int ovl_can_decode_fh(struct super_block *sb);
 200 struct dentry *ovl_indexdir(struct super_block *sb);
 201 bool ovl_index_all(struct super_block *sb);
 202 bool ovl_verify_lower(struct super_block *sb);
 203 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 204 bool ovl_dentry_remote(struct dentry *dentry);
 205 bool ovl_dentry_weird(struct dentry *dentry);
 206 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 207 void ovl_path_upper(struct dentry *dentry, struct path *path);
 208 void ovl_path_lower(struct dentry *dentry, struct path *path);
 209 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 210 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 211 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 212 struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
 213 struct dentry *ovl_dentry_real(struct dentry *dentry);
 214 struct dentry *ovl_i_dentry_upper(struct inode *inode);
 215 struct inode *ovl_inode_upper(struct inode *inode);
 216 struct inode *ovl_inode_lower(struct inode *inode);
 217 struct inode *ovl_inode_real(struct inode *inode);
 218 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
 219 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
 220 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
 221 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
 222 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
 223 bool ovl_dentry_is_opaque(struct dentry *dentry);
 224 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 225 void ovl_dentry_set_opaque(struct dentry *dentry);
 226 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
 227 void ovl_dentry_set_upper_alias(struct dentry *dentry);
 228 bool ovl_redirect_dir(struct super_block *sb);
 229 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 230 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
 231 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
 232                     struct dentry *lowerdentry);
 233 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 234 void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
 235 u64 ovl_dentry_version_get(struct dentry *dentry);
 236 bool ovl_is_whiteout(struct dentry *dentry);
 237 struct file *ovl_path_open(struct path *path, int flags);
 238 int ovl_copy_up_start(struct dentry *dentry);
 239 void ovl_copy_up_end(struct dentry *dentry);
 240 bool ovl_check_origin_xattr(struct dentry *dentry);
 241 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
 242 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 243                        const char *name, const void *value, size_t size,
 244                        int xerr);
 245 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 246 void ovl_set_flag(unsigned long flag, struct inode *inode);
 247 void ovl_clear_flag(unsigned long flag, struct inode *inode);
 248 bool ovl_test_flag(unsigned long flag, struct inode *inode);
 249 bool ovl_inuse_trylock(struct dentry *dentry);
 250 void ovl_inuse_unlock(struct dentry *dentry);
 251 bool ovl_need_index(struct dentry *dentry);
 252 int ovl_nlink_start(struct dentry *dentry, bool *locked);
 253 void ovl_nlink_end(struct dentry *dentry, bool locked);
 254 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
 255
 256 static inline bool ovl_is_impuredir(struct dentry *dentry)
 257 {
 258         return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
 259 }
 260
 261 static inline unsigned int ovl_xino_bits(struct super_block *sb)
 262 {
 263         struct ovl_fs *ofs = sb->s_fs_info;
 264
 265         return ofs->xino_bits;
 266 }
 267
 268
 269 /* namei.c */
 270 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
 271 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
 272                                   bool connected);
 273 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
 274                         struct dentry *upperdentry, struct ovl_path **stackp);
 275 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
 276                       struct dentry *real, bool is_upper, bool set);
 277 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
 278 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 279 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
 280 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
 281 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
 282                                 struct dentry *origin, bool verify);
 283 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
 284 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 285                           unsigned int flags);
 286 bool ovl_lower_positive(struct dentry *dentry);
 287
 288 static inline int ovl_verify_origin(struct dentry *upper,
 289                                     struct dentry *origin, bool set)
 290 {
 291         return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
 292 }
 293
 294 static inline int ovl_verify_upper(struct dentry *index,
 295                                     struct dentry *upper, bool set)
 296 {
 297         return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
 298 }
 299
 300 /* readdir.c */
 301 extern const struct file_operations ovl_dir_operations;
 302 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 303 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
 304 void ovl_cache_free(struct list_head *list);
 305 void ovl_dir_cache_free(struct inode *inode);
 306 int ovl_check_d_type_supported(struct path *realpath);
 307 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 308                          struct dentry *dentry, int level);
 309 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
 310
 311 /* inode.c */
 312 int ovl_set_nlink_upper(struct dentry *dentry);
 313 int ovl_set_nlink_lower(struct dentry *dentry);
 314 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
 315                            struct dentry *upperdentry,
 316                            unsigned int fallback);
 317 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 318 int ovl_getattr(const struct path *path, struct kstat *stat,
 319                 u32 request_mask, unsigned int flags);
 320 int ovl_permission(struct inode *inode, int mask);
 321 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 322                   const void *value, size_t size, int flags);
 323 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 324                   void *value, size_t size);
 325 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 326 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 327 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 328 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
 329 bool ovl_is_private_xattr(const char *name);
 330
 331 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 332 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
 333                                bool is_upper);
 334 struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
 335                             struct ovl_path *lowerpath, struct dentry *index,
 336                             unsigned int numlower);
 337 static inline void ovl_copyattr(struct inode *from, struct inode *to)
 338 {
 339         to->i_uid = from->i_uid;
 340         to->i_gid = from->i_gid;
 341         to->i_mode = from->i_mode;
 342         to->i_atime = from->i_atime;
 343         to->i_mtime = from->i_mtime;
 344         to->i_ctime = from->i_ctime;
 345 }
 346
 347 /* dir.c */
 348 extern const struct inode_operations ovl_dir_inode_operations;
 349 struct dentry *ovl_lookup_temp(struct dentry *workdir);
 350 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
 351                              struct dentry *dentry);
 352 struct ovl_cattr {
 353         dev_t rdev;
 354         umode_t mode;
 355         const char *link;
 356         struct dentry *hardlink;
 357 };
 358
 359 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
 360
 361 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
 362                                struct ovl_cattr *attr);
 363 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
 364
 365 /* copy_up.c */
 366 int ovl_copy_up(struct dentry *dentry);
 367 int ovl_copy_up_flags(struct dentry *dentry, int flags);
 368 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 369 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
 370 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
 371 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
 372                    struct dentry *upper);
 373
 374 /* export.c */
 375 extern const struct export_operations ovl_export_operations;