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