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