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