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 #define OVL_ISUPPER_MASK 1UL
  64
  65 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
  66 {
  67         int err = vfs_rmdir(dir, dentry);
  68         pr_debug("rmdir(%pd2) = %i\n", dentry, err);
  69         return err;
  70 }
  71
  72 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
  73 {
  74         int err = vfs_unlink(dir, dentry, NULL);
  75         pr_debug("unlink(%pd2) = %i\n", dentry, err);
  76         return err;
  77 }
  78
  79 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
  80                               struct dentry *new_dentry, bool debug)
  81 {
  82         int err = vfs_link(old_dentry, dir, new_dentry, NULL);
  83         if (debug) {
  84                 pr_debug("link(%pd2, %pd2) = %i\n",
  85                          old_dentry, new_dentry, err);
  86         }
  87         return err;
  88 }
  89
  90 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
  91                              umode_t mode, bool debug)
  92 {
  93         int err = vfs_create(dir, dentry, mode, true);
  94         if (debug)
  95                 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
  96         return err;
  97 }
  98
  99 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
 100                                umode_t mode, bool debug)
 101 {
 102         int err = vfs_mkdir(dir, dentry, mode);
 103         if (debug)
 104                 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
 105         return err;
 106 }
 107
 108 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
 109                                umode_t mode, dev_t dev, bool debug)
 110 {
 111         int err = vfs_mknod(dir, dentry, mode, dev);
 112         if (debug) {
 113                 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
 114                          dentry, mode, dev, err);
 115         }
 116         return err;
 117 }
 118
 119 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 120                                  const char *oldname, bool debug)
 121 {
 122         int err = vfs_symlink(dir, dentry, oldname);
 123         if (debug)
 124                 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
 125         return err;
 126 }
 127
 128 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 129                                   const void *value, size_t size, int flags)
 130 {
 131         int err = vfs_setxattr(dentry, name, value, size, flags);
 132         pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
 133                  dentry, name, (int) size, (char *) value, flags, err);
 134         return err;
 135 }
 136
 137 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
 138 {
 139         int err = vfs_removexattr(dentry, name);
 140         pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 141         return err;
 142 }
 143
 144 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
 145                                 struct inode *newdir, struct dentry *newdentry,
 146                                 unsigned int flags)
 147 {
 148         int err;
 149
 150         pr_debug("rename(%pd2, %pd2, 0x%x)\n",
 151                  olddentry, newdentry, flags);
 152
 153         err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
 154
 155         if (err) {
 156                 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
 157                          olddentry, newdentry, err);
 158         }
 159         return err;
 160 }
 161
 162 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
 163 {
 164         int err = vfs_whiteout(dir, dentry);
 165         pr_debug("whiteout(%pd2) = %i\n", dentry, err);
 166         return err;
 167 }
 168
 169 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
 170 {
 171         struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
 172         int err = IS_ERR(ret) ? PTR_ERR(ret) : 0;
 173
 174         pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
 175         return ret;
 176 }
 177
 178 static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper)
 179 {
 180         unsigned long x = (unsigned long) READ_ONCE(inode->i_private);
 181
 182         if (is_upper)
 183                 *is_upper = x & OVL_ISUPPER_MASK;
 184
 185         return (struct inode *) (x & ~OVL_ISUPPER_MASK);
 186 }
 187
 188 /* util.c */
 189 int ovl_want_write(struct dentry *dentry);
 190 void ovl_drop_write(struct dentry *dentry);
 191 struct dentry *ovl_workdir(struct dentry *dentry);
 192 const struct cred *ovl_override_creds(struct super_block *sb);
 193 struct super_block *ovl_same_sb(struct super_block *sb);
 194 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 195 bool ovl_dentry_remote(struct dentry *dentry);
 196 bool ovl_dentry_weird(struct dentry *dentry);
 197 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 198 void ovl_path_upper(struct dentry *dentry, struct path *path);
 199 void ovl_path_lower(struct dentry *dentry, struct path *path);
 200 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 201 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 202 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 203 struct dentry *ovl_dentry_real(struct dentry *dentry);
 204 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
 205 void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
 206 bool ovl_dentry_is_opaque(struct dentry *dentry);
 207 bool ovl_dentry_is_impure(struct dentry *dentry);
 208 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 209 void ovl_dentry_set_opaque(struct dentry *dentry);
 210 bool ovl_redirect_dir(struct super_block *sb);
 211 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 212 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
 213 void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
 214 void ovl_inode_init(struct inode *inode, struct inode *realinode,
 215                     bool is_upper);
 216 void ovl_inode_update(struct inode *inode, struct inode *upperinode);
 217 void ovl_dentry_version_inc(struct dentry *dentry);
 218 u64 ovl_dentry_version_get(struct dentry *dentry);
 219 bool ovl_is_whiteout(struct dentry *dentry);
 220 struct file *ovl_path_open(struct path *path, int flags);
 221 int ovl_copy_up_start(struct dentry *dentry);
 222 void ovl_copy_up_end(struct dentry *dentry);
 223 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
 224 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 225                        const char *name, const void *value, size_t size,
 226                        int xerr);
 227 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 228
 229 static inline bool ovl_is_impuredir(struct dentry *dentry)
 230 {
 231         return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
 232 }
 233
 234
 235 /* namei.c */
 236 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
 237 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
 238 bool ovl_lower_positive(struct dentry *dentry);
 239
 240 /* readdir.c */
 241 extern const struct file_operations ovl_dir_operations;
 242 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 243 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
 244 void ovl_cache_free(struct list_head *list);
 245 int ovl_check_d_type_supported(struct path *realpath);
 246 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 247                          struct dentry *dentry, int level);
 248
 249 /* inode.c */
 250 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 251 int ovl_getattr(const struct path *path, struct kstat *stat,
 252                 u32 request_mask, unsigned int flags);
 253 int ovl_permission(struct inode *inode, int mask);
 254 int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
 255                   size_t size, int flags);
 256 int ovl_xattr_get(struct dentry *dentry, const char *name,
 257                   void *value, size_t size);
 258 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 259 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 260 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 261 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
 262 bool ovl_is_private_xattr(const char *name);
 263
 264 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 265 struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode);
 266 static inline void ovl_copyattr(struct inode *from, struct inode *to)
 267 {
 268         to->i_uid = from->i_uid;
 269         to->i_gid = from->i_gid;
 270         to->i_mode = from->i_mode;
 271         to->i_atime = from->i_atime;
 272         to->i_mtime = from->i_mtime;
 273         to->i_ctime = from->i_ctime;
 274 }
 275
 276 /* dir.c */
 277 extern const struct inode_operations ovl_dir_inode_operations;
 278 struct dentry *ovl_lookup_temp(struct dentry *workdir);
 279 struct cattr {
 280         dev_t rdev;
 281         umode_t mode;
 282         const char *link;
 283 };
 284 int ovl_create_real(struct inode *dir, struct dentry *newdentry,
 285                     struct cattr *attr,
 286                     struct dentry *hardlink, bool debug);
 287 void ovl_cleanup(struct inode *dir, struct dentry *dentry);
 288
 289 /* copy_up.c */
 290 int ovl_copy_up(struct dentry *dentry);
 291 int ovl_copy_up_flags(struct dentry *dentry, int flags);
 292 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 293 int ovl_set_attr(struct dentry *upper, struct kstat *stat);