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_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 /*
  41  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
  42  * where:
  43  * origin.fh    - exported file handle of the lower file
  44  * origin.uuid  - uuid of the lower filesystem
  45  */
  46 #define OVL_FH_VERSION  0
  47 #define OVL_FH_MAGIC    0xfb
  48
  49 /* CPU byte order required for fid decoding:  */
  50 #define OVL_FH_FLAG_BIG_ENDIAN  (1 << 0)
  51 #define OVL_FH_FLAG_ANY_ENDIAN  (1 << 1)
  52 /* Is the real inode encoded in fid an upper inode? */
  53 #define OVL_FH_FLAG_PATH_UPPER  (1 << 2)
  54
  55 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
  56                          OVL_FH_FLAG_PATH_UPPER)
  57
  58 #if defined(__LITTLE_ENDIAN)
  59 #define OVL_FH_FLAG_CPU_ENDIAN 0
  60 #elif defined(__BIG_ENDIAN)
  61 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
  62 #else
  63 #error Endianness not defined
  64 #endif
  65
  66 /* On-disk and in-memeory format for redirect by file handle */
  67 struct ovl_fh {
  68         u8 version;     /* 0 */
  69         u8 magic;       /* 0xfb */
  70         u8 len;         /* size of this header + size of fid */
  71         u8 flags;       /* OVL_FH_FLAG_* */
  72         u8 type;        /* fid_type of fid */
  73         uuid_t uuid;    /* uuid of filesystem */
  74         u8 fid[0];      /* file identifier */
  75 } __packed;
  76
  77 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
  78 {
  79         int err = vfs_rmdir(dir, dentry);
  80         pr_debug("rmdir(%pd2) = %i\n", dentry, err);
  81         return err;
  82 }
  83
  84 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
  85 {
  86         int err = vfs_unlink(dir, dentry, NULL);
  87         pr_debug("unlink(%pd2) = %i\n", dentry, err);
  88         return err;
  89 }
  90
  91 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
  92                               struct dentry *new_dentry, bool debug)
  93 {
  94         int err = vfs_link(old_dentry, dir, new_dentry, NULL);
  95         if (debug) {
  96                 pr_debug("link(%pd2, %pd2) = %i\n",
  97                          old_dentry, new_dentry, err);
  98         }
  99         return err;
 100 }
 101
 102 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
 103                              umode_t mode, bool debug)
 104 {
 105         int err = vfs_create(dir, dentry, mode, true);
 106         if (debug)
 107                 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
 108         return err;
 109 }
 110
 111 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
 112                                umode_t mode, bool debug)
 113 {
 114         int err = vfs_mkdir(dir, dentry, mode);
 115         if (debug)
 116                 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
 117         return err;
 118 }
 119
 120 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
 121                                umode_t mode, dev_t dev, bool debug)
 122 {
 123         int err = vfs_mknod(dir, dentry, mode, dev);
 124         if (debug) {
 125                 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
 126                          dentry, mode, dev, err);
 127         }
 128         return err;
 129 }
 130
 131 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 132                                  const char *oldname, bool debug)
 133 {
 134         int err = vfs_symlink(dir, dentry, oldname);
 135         if (debug)
 136                 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
 137         return err;
 138 }
 139
 140 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 141                                   const void *value, size_t size, int flags)
 142 {
 143         int err = vfs_setxattr(dentry, name, value, size, flags);
 144         pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
 145                  dentry, name, (int) size, (char *) value, flags, err);
 146         return err;
 147 }
 148
 149 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
 150 {
 151         int err = vfs_removexattr(dentry, name);
 152         pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 153         return err;
 154 }
 155
 156 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
 157                                 struct inode *newdir, struct dentry *newdentry,
 158                                 unsigned int flags)
 159 {
 160         int err;
 161
 162         pr_debug("rename(%pd2, %pd2, 0x%x)\n",
 163                  olddentry, newdentry, flags);
 164
 165         err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
 166
 167         if (err) {
 168                 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
 169                          olddentry, newdentry, err);
 170         }
 171         return err;
 172 }
 173
 174 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
 175 {
 176         int err = vfs_whiteout(dir, dentry);
 177         pr_debug("whiteout(%pd2) = %i\n", dentry, err);
 178         return err;
 179 }
 180
 181 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
 182 {
 183         struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
 184         int err = PTR_ERR_OR_ZERO(ret);
 185
 186         pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
 187         return ret;
 188 }
 189
 190 /* util.c */
 191 int ovl_want_write(struct dentry *dentry);
 192 void ovl_drop_write(struct dentry *dentry);
 193 struct dentry *ovl_workdir(struct dentry *dentry);
 194 const struct cred *ovl_override_creds(struct super_block *sb);
 195 struct super_block *ovl_same_sb(struct super_block *sb);
 196 bool ovl_can_decode_fh(struct super_block *sb);
 197 struct dentry *ovl_indexdir(struct super_block *sb);
 198 bool ovl_index_all(struct super_block *sb);
 199 bool ovl_verify_lower(struct super_block *sb);
 200 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 201 bool ovl_dentry_remote(struct dentry *dentry);
 202 bool ovl_dentry_weird(struct dentry *dentry);
 203 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 204 void ovl_path_upper(struct dentry *dentry, struct path *path);
 205 void ovl_path_lower(struct dentry *dentry, struct path *path);
 206 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 207 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 208 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 209 struct dentry *ovl_dentry_real(struct dentry *dentry);
 210 struct dentry *ovl_i_dentry_upper(struct inode *inode);
 211 struct inode *ovl_inode_upper(struct inode *inode);
 212 struct inode *ovl_inode_lower(struct inode *inode);
 213 struct inode *ovl_inode_real(struct inode *inode);
 214 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
 215 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
 216 bool ovl_dentry_is_opaque(struct dentry *dentry);
 217 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 218 void ovl_dentry_set_opaque(struct dentry *dentry);
 219 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
 220 void ovl_dentry_set_upper_alias(struct dentry *dentry);
 221 bool ovl_redirect_dir(struct super_block *sb);
 222 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 223 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
 224 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
 225                     struct dentry *lowerdentry);
 226 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 227 void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
 228 u64 ovl_dentry_version_get(struct dentry *dentry);
 229 bool ovl_is_whiteout(struct dentry *dentry);
 230 struct file *ovl_path_open(struct path *path, int flags);
 231 int ovl_copy_up_start(struct dentry *dentry);
 232 void ovl_copy_up_end(struct dentry *dentry);
 233 bool ovl_check_origin_xattr(struct dentry *dentry);
 234 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
 235 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 236                        const char *name, const void *value, size_t size,
 237                        int xerr);
 238 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 239 void ovl_set_flag(unsigned long flag, struct inode *inode);
 240 void ovl_clear_flag(unsigned long flag, struct inode *inode);
 241 bool ovl_test_flag(unsigned long flag, struct inode *inode);
 242 bool ovl_inuse_trylock(struct dentry *dentry);
 243 void ovl_inuse_unlock(struct dentry *dentry);
 244 bool ovl_need_index(struct dentry *dentry);
 245 int ovl_nlink_start(struct dentry *dentry, bool *locked);
 246 void ovl_nlink_end(struct dentry *dentry, bool locked);
 247 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
 248
 249 static inline bool ovl_is_impuredir(struct dentry *dentry)
 250 {
 251         return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
 252 }
 253
 254
 255 /* namei.c */
 256 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
 257                       struct dentry *real, bool is_upper, bool set);
 258 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 259 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
 260 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
 261 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 262                           unsigned int flags);
 263 bool ovl_lower_positive(struct dentry *dentry);
 264
 265 static inline int ovl_verify_origin(struct dentry *upper,
 266                                     struct dentry *origin, bool set)
 267 {
 268         return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
 269 }
 270
 271 static inline int ovl_verify_upper(struct dentry *index,
 272                                     struct dentry *upper, bool set)
 273 {
 274         return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
 275 }
 276
 277 /* readdir.c */
 278 extern const struct file_operations ovl_dir_operations;
 279 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 280 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
 281 void ovl_cache_free(struct list_head *list);
 282 void ovl_dir_cache_free(struct inode *inode);
 283 int ovl_check_d_type_supported(struct path *realpath);
 284 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 285                          struct dentry *dentry, int level);
 286 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
 287
 288 /* inode.c */
 289 int ovl_set_nlink_upper(struct dentry *dentry);
 290 int ovl_set_nlink_lower(struct dentry *dentry);
 291 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
 292                            struct dentry *upperdentry,
 293                            unsigned int fallback);
 294 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 295 int ovl_getattr(const struct path *path, struct kstat *stat,
 296                 u32 request_mask, unsigned int flags);
 297 int ovl_permission(struct inode *inode, int mask);
 298 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 299                   const void *value, size_t size, int flags);
 300 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 301                   void *value, size_t size);
 302 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 303 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 304 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 305 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
 306 bool ovl_is_private_xattr(const char *name);
 307
 308 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 309 struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry,
 310                             struct dentry *index);
 311 static inline void ovl_copyattr(struct inode *from, struct inode *to)
 312 {
 313         to->i_uid = from->i_uid;
 314         to->i_gid = from->i_gid;
 315         to->i_mode = from->i_mode;
 316         to->i_atime = from->i_atime;
 317         to->i_mtime = from->i_mtime;
 318         to->i_ctime = from->i_ctime;
 319 }
 320
 321 /* dir.c */
 322 extern const struct inode_operations ovl_dir_inode_operations;
 323 struct dentry *ovl_lookup_temp(struct dentry *workdir);
 324 struct cattr {
 325         dev_t rdev;
 326         umode_t mode;
 327         const char *link;
 328 };
 329 int ovl_create_real(struct inode *dir, struct dentry *newdentry,
 330                     struct cattr *attr,
 331                     struct dentry *hardlink, bool debug);
 332 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
 333
 334 /* copy_up.c */
 335 int ovl_copy_up(struct dentry *dentry);
 336 int ovl_copy_up_flags(struct dentry *dentry, int flags);
 337 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 338 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
 339 struct ovl_fh *ovl_encode_fh(struct dentry *real, bool is_upper);
 340 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
 341                    struct dentry *upper);