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
  31 enum ovl_flag {
  32         /* Pure upper dir that may contain non pure upper entries */
  33         OVL_IMPURE,
  34         /* Non-merge dir that may contain whiteout entries */
  35         OVL_WHITEOUTS,
  36         OVL_INDEX,
  37 };
  38
  39 /*
  40  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
  41  * where:
  42  * origin.fh    - exported file handle of the lower file
  43  * origin.uuid  - uuid of the lower filesystem
  44  */
  45 #define OVL_FH_VERSION  0
  46 #define OVL_FH_MAGIC    0xfb
  47
  48 /* CPU byte order required for fid decoding:  */
  49 #define OVL_FH_FLAG_BIG_ENDIAN  (1 << 0)
  50 #define OVL_FH_FLAG_ANY_ENDIAN  (1 << 1)
  51 /* Is the real inode encoded in fid an upper inode? */
  52 #define OVL_FH_FLAG_PATH_UPPER  (1 << 2)
  53
  54 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
  55                          OVL_FH_FLAG_PATH_UPPER)
  56
  57 #if defined(__LITTLE_ENDIAN)
  58 #define OVL_FH_FLAG_CPU_ENDIAN 0
  59 #elif defined(__BIG_ENDIAN)
  60 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
  61 #else
  62 #error Endianness not defined
  63 #endif
  64
  65 /* On-disk and in-memeory format for redirect by file handle */
  66 struct ovl_fh {
  67         u8 version;     /* 0 */
  68         u8 magic;       /* 0xfb */
  69         u8 len;         /* size of this header + size of fid */
  70         u8 flags;       /* OVL_FH_FLAG_* */
  71         u8 type;        /* fid_type of fid */
  72         uuid_t uuid;    /* uuid of filesystem */
  73         u8 fid[0];      /* file identifier */
  74 } __packed;
  75
  76 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
  77 {
  78         int err = vfs_rmdir(dir, dentry);
  79         pr_debug("rmdir(%pd2) = %i\n", dentry, err);
  80         return err;
  81 }
  82
  83 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
  84 {
  85         int err = vfs_unlink(dir, dentry, NULL);
  86         pr_debug("unlink(%pd2) = %i\n", dentry, err);
  87         return err;
  88 }
  89
  90 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
  91                               struct dentry *new_dentry, bool debug)
  92 {
  93         int err = vfs_link(old_dentry, dir, new_dentry, NULL);
  94         if (debug) {
  95                 pr_debug("link(%pd2, %pd2) = %i\n",
  96                          old_dentry, new_dentry, err);
  97         }
  98         return err;
  99 }
 100
 101 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
 102                              umode_t mode, bool debug)
 103 {
 104         int err = vfs_create(dir, dentry, mode, true);
 105         if (debug)
 106                 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
 107         return err;
 108 }
 109
 110 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
 111                                umode_t mode, bool debug)
 112 {
 113         int err = vfs_mkdir(dir, dentry, mode);
 114         if (debug)
 115                 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
 116         return err;
 117 }
 118
 119 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
 120                                umode_t mode, dev_t dev, bool debug)
 121 {
 122         int err = vfs_mknod(dir, dentry, mode, dev);
 123         if (debug) {
 124                 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
 125                          dentry, mode, dev, err);
 126         }
 127         return err;
 128 }
 129
 130 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 131                                  const char *oldname, bool debug)
 132 {
 133         int err = vfs_symlink(dir, dentry, oldname);
 134         if (debug)
 135                 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
 136         return err;
 137 }
 138
 139 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 140                                   const void *value, size_t size, int flags)
 141 {
 142         int err = vfs_setxattr(dentry, name, value, size, flags);
 143         pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
 144                  dentry, name, (int) size, (char *) value, flags, err);
 145         return err;
 146 }
 147
 148 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
 149 {
 150         int err = vfs_removexattr(dentry, name);
 151         pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 152         return err;
 153 }
 154
 155 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
 156                                 struct inode *newdir, struct dentry *newdentry,
 157                                 unsigned int flags)
 158 {
 159         int err;
 160
 161         pr_debug("rename(%pd2, %pd2, 0x%x)\n",
 162                  olddentry, newdentry, flags);
 163
 164         err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
 165
 166         if (err) {
 167                 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
 168                          olddentry, newdentry, err);
 169         }
 170         return err;
 171 }
 172
 173 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
 174 {
 175         int err = vfs_whiteout(dir, dentry);
 176         pr_debug("whiteout(%pd2) = %i\n", dentry, err);
 177         return err;
 178 }
 179
 180 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
 181 {
 182         struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
 183         int err = IS_ERR(ret) ? PTR_ERR(ret) : 0;
 184
 185         pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
 186         return ret;
 187 }
 188
 189 /* util.c */
 190 int ovl_want_write(struct dentry *dentry);
 191 void ovl_drop_write(struct dentry *dentry);
 192 struct dentry *ovl_workdir(struct dentry *dentry);
 193 const struct cred *ovl_override_creds(struct super_block *sb);
 194 struct super_block *ovl_same_sb(struct super_block *sb);
 195 bool ovl_can_decode_fh(struct super_block *sb);
 196 struct dentry *ovl_indexdir(struct super_block *sb);
 197 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 198 bool ovl_dentry_remote(struct dentry *dentry);
 199 bool ovl_dentry_weird(struct dentry *dentry);
 200 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 201 void ovl_path_upper(struct dentry *dentry, struct path *path);
 202 void ovl_path_lower(struct dentry *dentry, struct path *path);
 203 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 204 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 205 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 206 struct dentry *ovl_dentry_real(struct dentry *dentry);
 207 struct dentry *ovl_i_dentry_upper(struct inode *inode);
 208 struct inode *ovl_inode_upper(struct inode *inode);
 209 struct inode *ovl_inode_lower(struct inode *inode);
 210 struct inode *ovl_inode_real(struct inode *inode);
 211 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
 212 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
 213 bool ovl_dentry_is_opaque(struct dentry *dentry);
 214 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 215 void ovl_dentry_set_opaque(struct dentry *dentry);
 216 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
 217 void ovl_dentry_set_upper_alias(struct dentry *dentry);
 218 bool ovl_redirect_dir(struct super_block *sb);
 219 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 220 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
 221 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
 222                     struct dentry *lowerdentry);
 223 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 224 void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
 225 u64 ovl_dentry_version_get(struct dentry *dentry);
 226 bool ovl_is_whiteout(struct dentry *dentry);
 227 struct file *ovl_path_open(struct path *path, int flags);
 228 int ovl_copy_up_start(struct dentry *dentry);
 229 void ovl_copy_up_end(struct dentry *dentry);
 230 bool ovl_check_origin_xattr(struct dentry *dentry);
 231 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
 232 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 233                        const char *name, const void *value, size_t size,
 234                        int xerr);
 235 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 236 void ovl_set_flag(unsigned long flag, struct inode *inode);
 237 void ovl_clear_flag(unsigned long flag, struct inode *inode);
 238 bool ovl_test_flag(unsigned long flag, struct inode *inode);
 239 bool ovl_inuse_trylock(struct dentry *dentry);
 240 void ovl_inuse_unlock(struct dentry *dentry);
 241 int ovl_nlink_start(struct dentry *dentry, bool *locked);
 242 void ovl_nlink_end(struct dentry *dentry, bool locked);
 243 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
 244
 245 static inline bool ovl_is_impuredir(struct dentry *dentry)
 246 {
 247         return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
 248 }
 249
 250
 251 /* namei.c */
 252 int ovl_verify_origin(struct dentry *dentry, struct dentry *origin,
 253                       bool is_upper, bool set);
 254 int ovl_verify_index(struct dentry *index, struct ovl_path *lower,
 255                      unsigned int numlower);
 256 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
 257 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
 258 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
 259 bool ovl_lower_positive(struct dentry *dentry);
 260
 261 /* readdir.c */
 262 extern const struct file_operations ovl_dir_operations;
 263 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 264 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
 265 void ovl_cache_free(struct list_head *list);
 266 void ovl_dir_cache_free(struct inode *inode);
 267 int ovl_check_d_type_supported(struct path *realpath);
 268 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 269                          struct dentry *dentry, int level);
 270 int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
 271                          struct ovl_path *lower, unsigned int numlower);
 272
 273 /* inode.c */
 274 int ovl_set_nlink_upper(struct dentry *dentry);
 275 int ovl_set_nlink_lower(struct dentry *dentry);
 276 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
 277                            struct dentry *upperdentry,
 278                            unsigned int fallback);
 279 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 280 int ovl_getattr(const struct path *path, struct kstat *stat,
 281                 u32 request_mask, unsigned int flags);
 282 int ovl_permission(struct inode *inode, int mask);
 283 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 284                   const void *value, size_t size, int flags);
 285 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 286                   void *value, size_t size);
 287 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 288 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 289 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 290 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
 291 bool ovl_is_private_xattr(const char *name);
 292
 293 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 294 struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry,
 295                             struct dentry *index);
 296 static inline void ovl_copyattr(struct inode *from, struct inode *to)
 297 {
 298         to->i_uid = from->i_uid;
 299         to->i_gid = from->i_gid;
 300         to->i_mode = from->i_mode;
 301         to->i_atime = from->i_atime;
 302         to->i_mtime = from->i_mtime;
 303         to->i_ctime = from->i_ctime;
 304 }
 305
 306 /* dir.c */
 307 extern const struct inode_operations ovl_dir_inode_operations;
 308 struct dentry *ovl_lookup_temp(struct dentry *workdir);
 309 struct cattr {
 310         dev_t rdev;
 311         umode_t mode;
 312         const char *link;
 313 };
 314 int ovl_create_real(struct inode *dir, struct dentry *newdentry,
 315                     struct cattr *attr,
 316                     struct dentry *hardlink, bool debug);
 317 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
 318
 319 /* copy_up.c */
 320 int ovl_copy_up(struct dentry *dentry);
 321 int ovl_copy_up_flags(struct dentry *dentry, int flags);
 322 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 323 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
 324 struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper);