Merge branch 'jk/ref-symlink-loop'
authorJunio C Hamano <gitster@pobox.com>
Mon, 17 Oct 2016 20:25:20 +0000 (13:25 -0700)
committerJunio C Hamano <gitster@pobox.com>
Mon, 17 Oct 2016 20:25:20 +0000 (13:25 -0700)
A stray symbolic link in $GIT_DIR/refs/ directory could make name
resolution loop forever, which has been corrected.

* jk/ref-symlink-loop:
files_read_raw_ref: prevent infinite retry loops in general
files_read_raw_ref: avoid infinite loop on broken symlinks

1  2 
refs/files-backend.c
diff --combined refs/files-backend.c
index d16feb19c57b1b74594947f8730b984e94c43def,2455564352e1dafd5a95cd25b7279ead69b24660..f9023939d5884e0f975d5997336313695e407ca1
@@@ -39,7 -39,7 +39,7 @@@ struct ref_value 
        struct object_id peeled;
  };
  
 -struct ref_cache;
 +struct files_ref_store;
  
  /*
   * Information used (along with the information in ref_entry) to
@@@ -78,8 -78,8 +78,8 @@@ struct ref_dir 
         */
        int sorted;
  
 -      /* A pointer to the ref_cache that contains this ref_dir. */
 -      struct ref_cache *ref_cache;
 +      /* A pointer to the files_ref_store that contains this ref_dir. */
 +      struct files_ref_store *ref_store;
  
        struct ref_entry **entries;
  };
@@@ -161,7 -161,7 +161,7 @@@ struct ref_entry 
  
  static void read_loose_refs(const char *dirname, struct ref_dir *dir);
  static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
 -static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
 +static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
                                          const char *dirname, size_t len,
                                          int incomplete);
  static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
@@@ -183,7 -183,7 +183,7 @@@ static struct ref_dir *get_ref_dir(stru
                        int pos = search_ref_dir(dir, "refs/bisect/", 12);
                        if (pos < 0) {
                                struct ref_entry *child_entry;
 -                              child_entry = create_dir_entry(dir->ref_cache,
 +                              child_entry = create_dir_entry(dir->ref_store,
                                                               "refs/bisect/",
                                                               12, 1);
                                add_entry_to_dir(dir, child_entry);
@@@ -261,13 -261,13 +261,13 @@@ static void clear_ref_dir(struct ref_di
   * dirname is the name of the directory with a trailing slash (e.g.,
   * "refs/heads/") or "" for the top-level directory.
   */
 -static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
 +static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
                                          const char *dirname, size_t len,
                                          int incomplete)
  {
        struct ref_entry *direntry;
        FLEX_ALLOC_MEM(direntry, name, dirname, len);
 -      direntry->u.subdir.ref_cache = ref_cache;
 +      direntry->u.subdir.ref_store = ref_store;
        direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
        return direntry;
  }
@@@ -343,7 -343,7 +343,7 @@@ static struct ref_dir *search_for_subdi
                 * therefore, create an empty record for it but mark
                 * the record complete.
                 */
 -              entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
 +              entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
                add_entry_to_dir(dir, entry);
        } else {
                entry = dir->entries[entry_index];
@@@ -501,7 -501,7 +501,7 @@@ static void sort_ref_dir(struct ref_di
        if (dir->sorted == dir->nr)
                return;
  
 -      qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
 +      QSORT(dir->entries, dir->nr, ref_entry_cmp);
  
        /* Remove any duplicates: */
        for (i = 0, j = 0; j < dir->nr; j++) {
@@@ -887,9 -887,9 +887,9 @@@ struct packed_ref_cache 
  
        /*
         * Count of references to the data structure in this instance,
 -       * including the pointer from ref_cache::packed if any.  The
 -       * data will not be freed as long as the reference count is
 -       * nonzero.
 +       * including the pointer from files_ref_store::packed if any.
 +       * The data will not be freed as long as the reference count
 +       * is nonzero.
         */
        unsigned int referrers;
  
   * Future: need to be in "struct repository"
   * when doing a full libification.
   */
 -static struct ref_cache {
 -      struct ref_cache *next;
 +struct files_ref_store {
 +      struct ref_store base;
        struct ref_entry *loose;
        struct packed_ref_cache *packed;
 -      /*
 -       * The submodule name, or "" for the main repo.  We allocate
 -       * length 1 rather than FLEX_ARRAY so that the main ref_cache
 -       * is initialized correctly.
 -       */
 -      char name[1];
 -} ref_cache, *submodule_ref_caches;
 +};
  
  /* Lock used for the main packed-refs file: */
  static struct lock_file packlock;
@@@ -943,7 -949,7 +943,7 @@@ static int release_packed_ref_cache(str
        }
  }
  
 -static void clear_packed_ref_cache(struct ref_cache *refs)
 +static void clear_packed_ref_cache(struct files_ref_store *refs)
  {
        if (refs->packed) {
                struct packed_ref_cache *packed_refs = refs->packed;
        }
  }
  
 -static void clear_loose_ref_cache(struct ref_cache *refs)
 +static void clear_loose_ref_cache(struct files_ref_store *refs)
  {
        if (refs->loose) {
                free_ref_entry(refs->loose);
   * Create a new submodule ref cache and add it to the internal
   * set of caches.
   */
 -static struct ref_cache *create_ref_cache(const char *submodule)
 -{
 -      struct ref_cache *refs;
 -      if (!submodule)
 -              submodule = "";
 -      FLEX_ALLOC_STR(refs, name, submodule);
 -      refs->next = submodule_ref_caches;
 -      submodule_ref_caches = refs;
 -      return refs;
 -}
 -
 -static struct ref_cache *lookup_ref_cache(const char *submodule)
 +static struct ref_store *files_ref_store_create(const char *submodule)
  {
 -      struct ref_cache *refs;
 +      struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 +      struct ref_store *ref_store = (struct ref_store *)refs;
  
 -      if (!submodule || !*submodule)
 -              return &ref_cache;
 +      base_ref_store_init(ref_store, &refs_be_files, submodule);
  
 -      for (refs = submodule_ref_caches; refs; refs = refs->next)
 -              if (!strcmp(submodule, refs->name))
 -                      return refs;
 -      return NULL;
 +      return ref_store;
  }
  
  /*
 - * Return a pointer to a ref_cache for the specified submodule. For
 - * the main repository, use submodule==NULL; such a call cannot fail.
 - * For a submodule, the submodule must exist and be a nonbare
 - * repository, otherwise return NULL.
 - *
 - * The returned structure will be allocated and initialized but not
 - * necessarily populated; it should not be freed.
 + * Downcast ref_store to files_ref_store. Die if ref_store is not a
 + * files_ref_store. If submodule_allowed is not true, then also die if
 + * files_ref_store is for a submodule (i.e., not for the main
 + * repository). caller is used in any necessary error messages.
   */
 -static struct ref_cache *get_ref_cache(const char *submodule)
 +static struct files_ref_store *files_downcast(
 +              struct ref_store *ref_store, int submodule_allowed,
 +              const char *caller)
  {
 -      struct ref_cache *refs = lookup_ref_cache(submodule);
 -
 -      if (!refs) {
 -              struct strbuf submodule_sb = STRBUF_INIT;
 +      if (ref_store->be != &refs_be_files)
 +              die("BUG: ref_store is type \"%s\" not \"files\" in %s",
 +                  ref_store->be->name, caller);
  
 -              strbuf_addstr(&submodule_sb, submodule);
 -              if (is_nonbare_repository_dir(&submodule_sb))
 -                      refs = create_ref_cache(submodule);
 -              strbuf_release(&submodule_sb);
 -      }
 +      if (!submodule_allowed)
 +              assert_main_repository(ref_store, caller);
  
 -      return refs;
 +      return (struct files_ref_store *)ref_store;
  }
  
  /* The length of a peeled reference line in packed-refs, including EOL: */
@@@ -1126,16 -1151,15 +1126,16 @@@ static void read_packed_refs(FILE *f, s
  }
  
  /*
 - * Get the packed_ref_cache for the specified ref_cache, creating it
 - * if necessary.
 + * Get the packed_ref_cache for the specified files_ref_store,
 + * creating it if necessary.
   */
 -static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs)
 +static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
  {
        char *packed_refs_file;
  
 -      if (*refs->name)
 -              packed_refs_file = git_pathdup_submodule(refs->name, "packed-refs");
 +      if (*refs->base.submodule)
 +              packed_refs_file = git_pathdup_submodule(refs->base.submodule,
 +                                                       "packed-refs");
        else
                packed_refs_file = git_pathdup("packed-refs");
  
@@@ -1165,7 -1189,7 +1165,7 @@@ static struct ref_dir *get_packed_ref_d
        return get_ref_dir(packed_ref_cache->root);
  }
  
 -static struct ref_dir *get_packed_refs(struct ref_cache *refs)
 +static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
  {
        return get_packed_ref_dir(get_packed_ref_cache(refs));
  }
   * lock_packed_refs()).  To actually write the packed-refs file, call
   * commit_packed_refs().
   */
 -static void add_packed_ref(const char *refname, const unsigned char *sha1)
 +static void add_packed_ref(struct files_ref_store *refs,
 +                         const char *refname, const unsigned char *sha1)
  {
 -      struct packed_ref_cache *packed_ref_cache =
 -              get_packed_ref_cache(&ref_cache);
 +      struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
  
        if (!packed_ref_cache->lock)
                die("internal error: packed refs not locked");
   */
  static void read_loose_refs(const char *dirname, struct ref_dir *dir)
  {
 -      struct ref_cache *refs = dir->ref_cache;
 +      struct files_ref_store *refs = dir->ref_store;
        DIR *d;
        struct dirent *de;
        int dirnamelen = strlen(dirname);
        struct strbuf refname;
        struct strbuf path = STRBUF_INIT;
        size_t path_baselen;
 +      int err = 0;
  
 -      if (*refs->name)
 -              strbuf_git_path_submodule(&path, refs->name, "%s", dirname);
 +      if (*refs->base.submodule)
 +              err = strbuf_git_path_submodule(&path, refs->base.submodule, "%s", dirname);
        else
                strbuf_git_path(&path, "%s", dirname);
        path_baselen = path.len;
  
 +      if (err) {
 +              strbuf_release(&path);
 +              return;
 +      }
 +
        d = opendir(path.buf);
        if (!d) {
                strbuf_release(&path);
                } else {
                        int read_ok;
  
 -                      if (*refs->name) {
 +                      if (*refs->base.submodule) {
                                hashclr(sha1);
                                flag = 0;
 -                              read_ok = !resolve_gitlink_ref(refs->name,
 +                              read_ok = !resolve_gitlink_ref(refs->base.submodule,
                                                               refname.buf, sha1);
                        } else {
                                read_ok = !read_ref_full(refname.buf,
        closedir(d);
  }
  
 -static struct ref_dir *get_loose_refs(struct ref_cache *refs)
 +static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
  {
        if (!refs->loose) {
                /*
        return get_ref_dir(refs->loose);
  }
  
 -#define MAXREFLEN (1024)
 -
 -/*
 - * Called by resolve_gitlink_ref_recursive() after it failed to read
 - * from the loose refs in ref_cache refs. Find <refname> in the
 - * packed-refs file for the submodule.
 - */
 -static int resolve_gitlink_packed_ref(struct ref_cache *refs,
 -                                    const char *refname, unsigned char *sha1)
 -{
 -      struct ref_entry *ref;
 -      struct ref_dir *dir = get_packed_refs(refs);
 -
 -      ref = find_ref(dir, refname);
 -      if (ref == NULL)
 -              return -1;
 -
 -      hashcpy(sha1, ref->u.value.oid.hash);
 -      return 0;
 -}
 -
 -static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
 -                                       const char *refname, unsigned char *sha1,
 -                                       int recursion)
 -{
 -      int fd, len;
 -      char buffer[128], *p;
 -      char *path;
 -
 -      if (recursion > SYMREF_MAXDEPTH || strlen(refname) > MAXREFLEN)
 -              return -1;
 -      path = *refs->name
 -              ? git_pathdup_submodule(refs->name, "%s", refname)
 -              : git_pathdup("%s", refname);
 -      fd = open(path, O_RDONLY);
 -      free(path);
 -      if (fd < 0)
 -              return resolve_gitlink_packed_ref(refs, refname, sha1);
 -
 -      len = read(fd, buffer, sizeof(buffer)-1);
 -      close(fd);
 -      if (len < 0)
 -              return -1;
 -      while (len && isspace(buffer[len-1]))
 -              len--;
 -      buffer[len] = 0;
 -
 -      /* Was it a detached head or an old-fashioned symlink? */
 -      if (!get_sha1_hex(buffer, sha1))
 -              return 0;
 -
 -      /* Symref? */
 -      if (strncmp(buffer, "ref:", 4))
 -              return -1;
 -      p = buffer + 4;
 -      while (isspace(*p))
 -              p++;
 -
 -      return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
 -}
 -
 -int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
 -{
 -      int len = strlen(path), retval;
 -      struct strbuf submodule = STRBUF_INIT;
 -      struct ref_cache *refs;
 -
 -      while (len && path[len-1] == '/')
 -              len--;
 -      if (!len)
 -              return -1;
 -
 -      strbuf_add(&submodule, path, len);
 -      refs = get_ref_cache(submodule.buf);
 -      if (!refs) {
 -              strbuf_release(&submodule);
 -              return -1;
 -      }
 -      strbuf_release(&submodule);
 -
 -      retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
 -      return retval;
 -}
 -
  /*
   * Return the ref_entry for the given refname from the packed
   * references.  If it does not exist, return NULL.
   */
 -static struct ref_entry *get_packed_ref(const char *refname)
 +static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
 +                                      const char *refname)
  {
 -      return find_ref(get_packed_refs(&ref_cache), refname);
 +      return find_ref(get_packed_refs(refs), refname);
  }
  
  /*
   * A loose ref file doesn't exist; check for a packed ref.
   */
 -static int resolve_missing_loose_ref(const char *refname,
 -                                   unsigned char *sha1,
 -                                   unsigned int *flags)
 +static int resolve_packed_ref(struct files_ref_store *refs,
 +                            const char *refname,
 +                            unsigned char *sha1, unsigned int *flags)
  {
        struct ref_entry *entry;
  
         * The loose reference file does not exist; check for a packed
         * reference.
         */
 -      entry = get_packed_ref(refname);
 +      entry = get_packed_ref(refs, refname);
        if (entry) {
                hashcpy(sha1, entry->u.value.oid.hash);
                *flags |= REF_ISPACKED;
        return -1;
  }
  
 -int read_raw_ref(const char *refname, unsigned char *sha1,
 -               struct strbuf *referent, unsigned int *type)
 +static int files_read_raw_ref(struct ref_store *ref_store,
 +                            const char *refname, unsigned char *sha1,
 +                            struct strbuf *referent, unsigned int *type)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 1, "read_raw_ref");
        struct strbuf sb_contents = STRBUF_INIT;
        struct strbuf sb_path = STRBUF_INIT;
        const char *path;
        int fd;
        int ret = -1;
        int save_errno;
+       int remaining_retries = 3;
  
        *type = 0;
        strbuf_reset(&sb_path);
 -      strbuf_git_path(&sb_path, "%s", refname);
 +
 +      if (*refs->base.submodule)
 +              strbuf_git_path_submodule(&sb_path, refs->base.submodule, "%s", refname);
 +      else
 +              strbuf_git_path(&sb_path, "%s", refname);
 +
        path = sb_path.buf;
  
  stat_ref:
         * <-> symlink) between the lstat() and reading, then
         * we don't want to report that as an error but rather
         * try again starting with the lstat().
+        *
+        * We'll keep a count of the retries, though, just to avoid
+        * any confusing situation sending us into an infinite loop.
         */
  
+       if (remaining_retries-- <= 0)
+               goto out;
        if (lstat(path, &st) < 0) {
                if (errno != ENOENT)
                        goto out;
 -              if (resolve_missing_loose_ref(refname, sha1, type)) {
 +              if (resolve_packed_ref(refs, refname, sha1, type)) {
                        errno = ENOENT;
                        goto out;
                }
                        ret = 0;
                        goto out;
                }
+               /*
+                * It doesn't look like a refname; fall through to just
+                * treating it like a non-symlink, and reading whatever it
+                * points to.
+                */
        }
  
        /* Is it a directory? */
                 * ref is supposed to be, there could still be a
                 * packed ref:
                 */
 -              if (resolve_missing_loose_ref(refname, sha1, type)) {
 +              if (resolve_packed_ref(refs, refname, sha1, type)) {
                        errno = EISDIR;
                        goto out;
                }
         */
        fd = open(path, O_RDONLY);
        if (fd < 0) {
-               if (errno == ENOENT)
+               if (errno == ENOENT && !S_ISLNK(st.st_mode))
                        /* inconsistent with lstat; retry */
                        goto stat_ref;
                else
@@@ -1513,8 -1618,7 +1525,8 @@@ static void unlock_ref(struct ref_lock 
   *   avoided, namely if we were successfully able to read the ref
   * - Generate informative error messages in the case of failure
   */
 -static int lock_raw_ref(const char *refname, int mustexist,
 +static int lock_raw_ref(struct files_ref_store *refs,
 +                      const char *refname, int mustexist,
                        const struct string_list *extras,
                        const struct string_list *skip,
                        struct ref_lock **lock_p,
        int ret = TRANSACTION_GENERIC_ERROR;
  
        assert(err);
 +      assert_main_repository(&refs->base, "lock_raw_ref");
 +
        *type = 0;
  
        /* First lock the file so it can't change out from under us. */
@@@ -1613,8 -1715,7 +1625,8 @@@ retry
         * fear that its value will change.
         */
  
 -      if (read_raw_ref(refname, lock->old_oid.hash, referent, type)) {
 +      if (files_read_raw_ref(&refs->base, refname,
 +                             lock->old_oid.hash, referent, type)) {
                if (errno == ENOENT) {
                        if (mustexist) {
                                /* Garden variety missing reference. */
                                                          REMOVE_DIR_EMPTY_ONLY)) {
                                if (verify_refname_available_dir(
                                                    refname, extras, skip,
 -                                                  get_loose_refs(&ref_cache),
 +                                                  get_loose_refs(refs),
                                                    err)) {
                                        /*
                                         * The error message set by
                 */
                if (verify_refname_available_dir(
                                    refname, extras, skip,
 -                                  get_packed_refs(&ref_cache),
 +                                  get_packed_refs(refs),
                                    err)) {
                        goto error_return;
                }
@@@ -1749,10 -1850,8 +1761,10 @@@ static enum peel_status peel_entry(stru
        return status;
  }
  
 -int peel_ref(const char *refname, unsigned char *sha1)
 +static int files_peel_ref(struct ref_store *ref_store,
 +                        const char *refname, unsigned char *sha1)
  {
 +      struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
        int flag;
        unsigned char base[20];
  
         * have REF_KNOWS_PEELED.
         */
        if (flag & REF_ISPACKED) {
 -              struct ref_entry *r = get_packed_ref(refname);
 +              struct ref_entry *r = get_packed_ref(refs, refname);
                if (r) {
                        if (peel_entry(r, 0))
                                return -1;
@@@ -1804,10 -1903,6 +1816,10 @@@ static int files_ref_iterator_advance(s
        int ok;
  
        while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
 +              if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
 +                  ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
 +                      continue;
 +
                if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
                    !ref_resolves_to_object(iter->iter0->refname,
                                            iter->iter0->oid,
@@@ -1856,12 -1951,11 +1868,12 @@@ static struct ref_iterator_vtable files
        files_ref_iterator_abort
  };
  
 -struct ref_iterator *files_ref_iterator_begin(
 -              const char *submodule,
 +static struct ref_iterator *files_ref_iterator_begin(
 +              struct ref_store *ref_store,
                const char *prefix, unsigned int flags)
  {
 -      struct ref_cache *refs = get_ref_cache(submodule);
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 1, "ref_iterator_begin");
        struct ref_dir *loose_dir, *packed_dir;
        struct ref_iterator *loose_iter, *packed_iter;
        struct files_ref_iterator *iter;
@@@ -1977,8 -2071,7 +1989,8 @@@ static int remove_empty_directories(str
   * Locks a ref returning the lock on success and NULL on failure.
   * On failure errno is set to something meaningful.
   */
 -static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 +static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 +                                          const char *refname,
                                            const unsigned char *old_sha1,
                                            const struct string_list *extras,
                                            const struct string_list *skip,
        int attempts_remaining = 3;
        int resolved;
  
 +      assert_main_repository(&refs->base, "lock_ref_sha1_basic");
        assert(err);
  
        lock = xcalloc(1, sizeof(struct ref_lock));
                 */
                if (remove_empty_directories(&ref_file)) {
                        last_errno = errno;
 -                      if (!verify_refname_available_dir(refname, extras, skip,
 -                                                        get_loose_refs(&ref_cache), err))
 +                      if (!verify_refname_available_dir(
 +                                          refname, extras, skip,
 +                                          get_loose_refs(refs), err))
                                strbuf_addf(err, "there are still refs under '%s'",
                                            refname);
                        goto error_return;
        if (!resolved) {
                last_errno = errno;
                if (last_errno != ENOTDIR ||
 -                  !verify_refname_available_dir(refname, extras, skip,
 -                                                get_loose_refs(&ref_cache), err))
 +                  !verify_refname_available_dir(
 +                                  refname, extras, skip,
 +                                  get_loose_refs(refs), err))
                        strbuf_addf(err, "unable to resolve reference '%s': %s",
                                    refname, strerror(last_errno));
  
         */
        if (is_null_oid(&lock->old_oid) &&
            verify_refname_available_dir(refname, extras, skip,
 -                                       get_packed_refs(&ref_cache), err)) {
 +                                       get_packed_refs(refs),
 +                                       err)) {
                last_errno = ENOTDIR;
                goto error_return;
        }
@@@ -2134,14 -2223,13 +2146,14 @@@ static int write_packed_entry_fn(struc
   * hold_lock_file_for_update(). Return 0 on success. On errors, set
   * errno appropriately and return a nonzero value.
   */
 -static int lock_packed_refs(int flags)
 +static int lock_packed_refs(struct files_ref_store *refs, int flags)
  {
        static int timeout_configured = 0;
        static int timeout_value = 1000;
 -
        struct packed_ref_cache *packed_ref_cache;
  
 +      assert_main_repository(&refs->base, "lock_packed_refs");
 +
        if (!timeout_configured) {
                git_config_get_int("core.packedrefstimeout", &timeout_value);
                timeout_configured = 1;
         * this will automatically invalidate the cache and re-read
         * the packed-refs file.
         */
 -      packed_ref_cache = get_packed_ref_cache(&ref_cache);
 +      packed_ref_cache = get_packed_ref_cache(refs);
        packed_ref_cache->lock = &packlock;
        /* Increment the reference count to prevent it from being freed: */
        acquire_packed_ref_cache(packed_ref_cache);
   * lock_packed_refs()). Return zero on success. On errors, set errno
   * and return a nonzero value
   */
 -static int commit_packed_refs(void)
 +static int commit_packed_refs(struct files_ref_store *refs)
  {
        struct packed_ref_cache *packed_ref_cache =
 -              get_packed_ref_cache(&ref_cache);
 +              get_packed_ref_cache(refs);
        int error = 0;
        int save_errno = 0;
        FILE *out;
  
 +      assert_main_repository(&refs->base, "commit_packed_refs");
 +
        if (!packed_ref_cache->lock)
                die("internal error: packed-refs not locked");
  
   * in-memory packed reference cache.  (The packed-refs file will be
   * read anew if it is needed again after this function is called.)
   */
 -static void rollback_packed_refs(void)
 +static void rollback_packed_refs(struct files_ref_store *refs)
  {
        struct packed_ref_cache *packed_ref_cache =
 -              get_packed_ref_cache(&ref_cache);
 +              get_packed_ref_cache(refs);
 +
 +      assert_main_repository(&refs->base, "rollback_packed_refs");
  
        if (!packed_ref_cache->lock)
                die("internal error: packed-refs not locked");
        rollback_lock_file(packed_ref_cache->lock);
        packed_ref_cache->lock = NULL;
        release_packed_ref_cache(packed_ref_cache);
 -      clear_packed_ref_cache(&ref_cache);
 +      clear_packed_ref_cache(refs);
  }
  
  struct ref_to_prune {
@@@ -2349,22 -2433,20 +2361,22 @@@ static void prune_refs(struct ref_to_pr
        }
  }
  
 -int pack_refs(unsigned int flags)
 +static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "pack_refs");
        struct pack_refs_cb_data cbdata;
  
        memset(&cbdata, 0, sizeof(cbdata));
        cbdata.flags = flags;
  
 -      lock_packed_refs(LOCK_DIE_ON_ERROR);
 -      cbdata.packed_refs = get_packed_refs(&ref_cache);
 +      lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
 +      cbdata.packed_refs = get_packed_refs(refs);
  
 -      do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0,
 +      do_for_each_entry_in_dir(get_loose_refs(refs), 0,
                                 pack_if_possible_fn, &cbdata);
  
 -      if (commit_packed_refs())
 +      if (commit_packed_refs(refs))
                die_errno("unable to overwrite old ref-pack file");
  
        prune_refs(cbdata.ref_to_prune);
   *
   * The refs in 'refnames' needn't be sorted. `err` must not be NULL.
   */
 -static int repack_without_refs(struct string_list *refnames, struct strbuf *err)
 +static int repack_without_refs(struct files_ref_store *refs,
 +                             struct string_list *refnames, struct strbuf *err)
  {
        struct ref_dir *packed;
        struct string_list_item *refname;
        int ret, needs_repacking = 0, removed = 0;
  
 +      assert_main_repository(&refs->base, "repack_without_refs");
        assert(err);
  
        /* Look for a packed ref */
        for_each_string_list_item(refname, refnames) {
 -              if (get_packed_ref(refname->string)) {
 +              if (get_packed_ref(refs, refname->string)) {
                        needs_repacking = 1;
                        break;
                }
        if (!needs_repacking)
                return 0; /* no refname exists in packed refs */
  
 -      if (lock_packed_refs(0)) {
 +      if (lock_packed_refs(refs, 0)) {
                unable_to_lock_message(git_path("packed-refs"), errno, err);
                return -1;
        }
 -      packed = get_packed_refs(&ref_cache);
 +      packed = get_packed_refs(refs);
  
        /* Remove refnames from the cache */
        for_each_string_list_item(refname, refnames)
                 * All packed entries disappeared while we were
                 * acquiring the lock.
                 */
 -              rollback_packed_refs();
 +              rollback_packed_refs(refs);
                return 0;
        }
  
        /* Write what remains */
 -      ret = commit_packed_refs();
 +      ret = commit_packed_refs(refs);
        if (ret)
                strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
                            strerror(errno));
@@@ -2445,18 -2525,15 +2457,18 @@@ static int delete_ref_loose(struct ref_
        return 0;
  }
  
 -int delete_refs(struct string_list *refnames, unsigned int flags)
 +static int files_delete_refs(struct ref_store *ref_store,
 +                           struct string_list *refnames, unsigned int flags)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "delete_refs");
        struct strbuf err = STRBUF_INIT;
        int i, result = 0;
  
        if (!refnames->nr)
                return 0;
  
 -      result = repack_without_refs(refnames, &err);
 +      result = repack_without_refs(refs, refnames, &err);
        if (result) {
                /*
                 * If we failed to rewrite the packed-refs file, then
        return ret;
  }
  
 -int verify_refname_available(const char *newname,
 -                           const struct string_list *extras,
 -                           const struct string_list *skip,
 -                           struct strbuf *err)
 +static int files_verify_refname_available(struct ref_store *ref_store,
 +                                        const char *newname,
 +                                        const struct string_list *extras,
 +                                        const struct string_list *skip,
 +                                        struct strbuf *err)
  {
 -      struct ref_dir *packed_refs = get_packed_refs(&ref_cache);
 -      struct ref_dir *loose_refs = get_loose_refs(&ref_cache);
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 1, "verify_refname_available");
 +      struct ref_dir *packed_refs = get_packed_refs(refs);
 +      struct ref_dir *loose_refs = get_loose_refs(refs);
  
        if (verify_refname_available_dir(newname, extras, skip,
                                         packed_refs, err) ||
  
  static int write_ref_to_lockfile(struct ref_lock *lock,
                                 const unsigned char *sha1, struct strbuf *err);
 -static int commit_ref_update(struct ref_lock *lock,
 +static int commit_ref_update(struct files_ref_store *refs,
 +                           struct ref_lock *lock,
                             const unsigned char *sha1, const char *logmsg,
                             struct strbuf *err);
  
 -int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
 +static int files_rename_ref(struct ref_store *ref_store,
 +                          const char *oldrefname, const char *newrefname,
 +                          const char *logmsg)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "rename_ref");
        unsigned char sha1[20], orig_sha1[20];
        int flag = 0, logmoved = 0;
        struct ref_lock *lock;
  
        logmoved = log;
  
 -      lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, REF_NODEREF,
 -                                 NULL, &err);
 +      lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
 +                                 REF_NODEREF, NULL, &err);
        if (!lock) {
                error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
                strbuf_release(&err);
        hashcpy(lock->old_oid.hash, orig_sha1);
  
        if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
 -          commit_ref_update(lock, orig_sha1, logmsg, &err)) {
 +          commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) {
                error("unable to write current sha1 into %s: %s", newrefname, err.buf);
                strbuf_release(&err);
                goto rollback;
        return 0;
  
   rollback:
 -      lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, REF_NODEREF,
 -                                 NULL, &err);
 +      lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
 +                                 REF_NODEREF, NULL, &err);
        if (!lock) {
                error("unable to lock %s for rollback: %s", oldrefname, err.buf);
                strbuf_release(&err);
        flag = log_all_ref_updates;
        log_all_ref_updates = 0;
        if (write_ref_to_lockfile(lock, orig_sha1, &err) ||
 -          commit_ref_update(lock, orig_sha1, NULL, &err)) {
 +          commit_ref_update(refs, lock, orig_sha1, NULL, &err)) {
                error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
                strbuf_release(&err);
        }
@@@ -2775,16 -2844,11 +2787,16 @@@ static int log_ref_setup(const char *re
  }
  
  
 -int safe_create_reflog(const char *refname, int force_create, struct strbuf *err)
 +static int files_create_reflog(struct ref_store *ref_store,
 +                             const char *refname, int force_create,
 +                             struct strbuf *err)
  {
        int ret;
        struct strbuf sb = STRBUF_INIT;
  
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "create_reflog");
 +
        ret = log_ref_setup(refname, &sb, err, force_create);
        strbuf_release(&sb);
        return ret;
@@@ -2913,14 -2977,11 +2925,14 @@@ static int write_ref_to_lockfile(struc
   * to the loose reference lockfile. Also update the reflogs if
   * necessary, using the specified lockmsg (which can be NULL).
   */
 -static int commit_ref_update(struct ref_lock *lock,
 +static int commit_ref_update(struct files_ref_store *refs,
 +                           struct ref_lock *lock,
                             const unsigned char *sha1, const char *logmsg,
                             struct strbuf *err)
  {
 -      clear_loose_ref_cache(&ref_cache);
 +      assert_main_repository(&refs->base, "commit_ref_update");
 +
 +      clear_loose_ref_cache(refs);
        if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
                char *old_msg = strbuf_detach(err, NULL);
                strbuf_addf(err, "cannot update the ref '%s': %s",
@@@ -3019,18 -3080,13 +3031,18 @@@ static int create_symref_locked(struct 
        return 0;
  }
  
 -int create_symref(const char *refname, const char *target, const char *logmsg)
 +static int files_create_symref(struct ref_store *ref_store,
 +                             const char *refname, const char *target,
 +                             const char *logmsg)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "create_symref");
        struct strbuf err = STRBUF_INIT;
        struct ref_lock *lock;
        int ret;
  
 -      lock = lock_ref_sha1_basic(refname, NULL, NULL, NULL, REF_NODEREF, NULL,
 +      lock = lock_ref_sha1_basic(refs, refname, NULL,
 +                                 NULL, NULL, REF_NODEREF, NULL,
                                   &err);
        if (!lock) {
                error("%s", err.buf);
@@@ -3078,24 -3134,16 +3090,24 @@@ int set_worktree_head_symref(const cha
        return ret;
  }
  
 -int reflog_exists(const char *refname)
 +static int files_reflog_exists(struct ref_store *ref_store,
 +                             const char *refname)
  {
        struct stat st;
  
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "reflog_exists");
 +
        return !lstat(git_path("logs/%s", refname), &st) &&
                S_ISREG(st.st_mode);
  }
  
 -int delete_reflog(const char *refname)
 +static int files_delete_reflog(struct ref_store *ref_store,
 +                             const char *refname)
  {
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "delete_reflog");
 +
        return remove_path(git_path("logs/%s", refname));
  }
  
@@@ -3138,19 -3186,13 +3150,19 @@@ static char *find_beginning_of_line(cha
        return scan;
  }
  
 -int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
 +static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 +                                           const char *refname,
 +                                           each_reflog_ent_fn fn,
 +                                           void *cb_data)
  {
        struct strbuf sb = STRBUF_INIT;
        FILE *logfp;
        long pos;
        int ret = 0, at_tail = 1;
  
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 +
        logfp = fopen(git_path("logs/%s", refname), "r");
        if (!logfp)
                return -1;
        return ret;
  }
  
 -int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
 +static int files_for_each_reflog_ent(struct ref_store *ref_store,
 +                                   const char *refname,
 +                                   each_reflog_ent_fn fn, void *cb_data)
  {
        FILE *logfp;
        struct strbuf sb = STRBUF_INIT;
        int ret = 0;
  
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "for_each_reflog_ent");
 +
        logfp = fopen(git_path("logs/%s", refname), "r");
        if (!logfp)
                return -1;
@@@ -3335,19 -3372,22 +3347,19 @@@ static struct ref_iterator_vtable files
        files_reflog_iterator_abort
  };
  
 -struct ref_iterator *files_reflog_iterator_begin(void)
 +static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
  {
        struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
        struct ref_iterator *ref_iterator = &iter->base;
  
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "reflog_iterator_begin");
 +
        base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
        iter->dir_iterator = dir_iterator_begin(git_path("logs"));
        return ref_iterator;
  }
  
 -int for_each_reflog(each_ref_fn fn, void *cb_data)
 -{
 -      return do_for_each_ref_iterator(files_reflog_iterator_begin(),
 -                                      fn, cb_data);
 -}
 -
  static int ref_update_reject_duplicates(struct string_list *refnames,
                                        struct strbuf *err)
  {
@@@ -3420,8 -3460,7 +3432,8 @@@ static int split_head_update(struct ref
   * Note that the new update will itself be subject to splitting when
   * the iteration gets to it.
   */
 -static int split_symref_update(struct ref_update *update,
 +static int split_symref_update(struct files_ref_store *refs,
 +                             struct ref_update *update,
                               const char *referent,
                               struct ref_transaction *transaction,
                               struct string_list *affected_refnames,
@@@ -3535,8 -3574,7 +3547,8 @@@ static int check_old_oid(struct ref_upd
   * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
   *   update of HEAD.
   */
 -static int lock_ref_for_update(struct ref_update *update,
 +static int lock_ref_for_update(struct files_ref_store *refs,
 +                             struct ref_update *update,
                               struct ref_transaction *transaction,
                               const char *head_ref,
                               struct string_list *affected_refnames,
        int ret;
        struct ref_lock *lock;
  
 +      assert_main_repository(&refs->base, "lock_ref_for_update");
 +
        if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
                update->flags |= REF_DELETING;
  
                        return ret;
        }
  
 -      ret = lock_raw_ref(update->refname, mustexist,
 +      ret = lock_raw_ref(refs, update->refname, mustexist,
                           affected_refnames, NULL,
 -                         &update->lock, &referent,
 +                         &lock, &referent,
                           &update->type, err);
 -
        if (ret) {
                char *reason;
  
                return ret;
        }
  
 -      lock = update->lock;
 +      update->backend_data = lock;
  
        if (update->type & REF_ISSYMREF) {
                if (update->flags & REF_NODEREF) {
                         * of processing the split-off update, so we
                         * don't have to do it here.
                         */
 -                      ret = split_symref_update(update, referent.buf, transaction,
 +                      ret = split_symref_update(refs, update,
 +                                                referent.buf, transaction,
                                                  affected_refnames, err);
                        if (ret)
                                return ret;
                for (parent_update = update->parent_update;
                     parent_update;
                     parent_update = parent_update->parent_update) {
 -                      oidcpy(&parent_update->lock->old_oid, &lock->old_oid);
 +                      struct ref_lock *parent_lock = parent_update->backend_data;
 +                      oidcpy(&parent_lock->old_oid, &lock->old_oid);
                }
        }
  
                         * The lock was freed upon failure of
                         * write_ref_to_lockfile():
                         */
 -                      update->lock = NULL;
 +                      update->backend_data = NULL;
                        strbuf_addf(err,
                                    "cannot update ref '%s': %s",
                                    update->refname, write_err);
        return 0;
  }
  
 -int ref_transaction_commit(struct ref_transaction *transaction,
 -                         struct strbuf *err)
 +static int files_transaction_commit(struct ref_store *ref_store,
 +                                  struct ref_transaction *transaction,
 +                                  struct strbuf *err)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "ref_transaction_commit");
        int ret = 0, i;
        struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
        struct string_list_item *ref_to_delete;
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
  
 -              ret = lock_ref_for_update(update, transaction, head_ref,
 -                                        &affected_refnames, err);
 +              ret = lock_ref_for_update(refs, update, transaction,
 +                                        head_ref, &affected_refnames, err);
                if (ret)
                        goto cleanup;
        }
        /* Perform updates first so live commits remain referenced */
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
 -              struct ref_lock *lock = update->lock;
 +              struct ref_lock *lock = update->backend_data;
  
                if (update->flags & REF_NEEDS_COMMIT ||
                    update->flags & REF_LOG_ONLY) {
                                            lock->ref_name, old_msg);
                                free(old_msg);
                                unlock_ref(lock);
 -                              update->lock = NULL;
 +                              update->backend_data = NULL;
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
                        }
                }
                if (update->flags & REF_NEEDS_COMMIT) {
 -                      clear_loose_ref_cache(&ref_cache);
 +                      clear_loose_ref_cache(refs);
                        if (commit_ref(lock)) {
                                strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
                                unlock_ref(lock);
 -                              update->lock = NULL;
 +                              update->backend_data = NULL;
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
                        }
        /* Perform deletes now that updates are safely completed */
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
 +              struct ref_lock *lock = update->backend_data;
  
                if (update->flags & REF_DELETING &&
                    !(update->flags & REF_LOG_ONLY)) {
 -                      if (delete_ref_loose(update->lock, update->type, err)) {
 +                      if (delete_ref_loose(lock, update->type, err)) {
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
                        }
  
                        if (!(update->flags & REF_ISPRUNING))
                                string_list_append(&refs_to_delete,
 -                                                 update->lock->ref_name);
 +                                                 lock->ref_name);
                }
        }
  
 -      if (repack_without_refs(&refs_to_delete, err)) {
 +      if (repack_without_refs(refs, &refs_to_delete, err)) {
                ret = TRANSACTION_GENERIC_ERROR;
                goto cleanup;
        }
        for_each_string_list_item(ref_to_delete, &refs_to_delete)
                unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
 -      clear_loose_ref_cache(&ref_cache);
 +      clear_loose_ref_cache(refs);
  
  cleanup:
        transaction->state = REF_TRANSACTION_CLOSED;
  
        for (i = 0; i < transaction->nr; i++)
 -              if (transaction->updates[i]->lock)
 -                      unlock_ref(transaction->updates[i]->lock);
 +              if (transaction->updates[i]->backend_data)
 +                      unlock_ref(transaction->updates[i]->backend_data);
        string_list_clear(&refs_to_delete, 0);
        free(head_ref);
        string_list_clear(&affected_refnames, 0);
@@@ -3838,12 -3869,9 +3850,12 @@@ static int ref_present(const char *refn
        return string_list_has_string(affected_refnames, refname);
  }
  
 -int initial_ref_transaction_commit(struct ref_transaction *transaction,
 -                                 struct strbuf *err)
 +static int files_initial_transaction_commit(struct ref_store *ref_store,
 +                                          struct ref_transaction *transaction,
 +                                          struct strbuf *err)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "initial_ref_transaction_commit");
        int ret = 0, i;
        struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
  
                }
        }
  
 -      if (lock_packed_refs(0)) {
 +      if (lock_packed_refs(refs, 0)) {
                strbuf_addf(err, "unable to lock packed-refs file: %s",
                            strerror(errno));
                ret = TRANSACTION_GENERIC_ERROR;
  
                if ((update->flags & REF_HAVE_NEW) &&
                    !is_null_sha1(update->new_sha1))
 -                      add_packed_ref(update->refname, update->new_sha1);
 +                      add_packed_ref(refs, update->refname, update->new_sha1);
        }
  
 -      if (commit_packed_refs()) {
 +      if (commit_packed_refs(refs)) {
                strbuf_addf(err, "unable to commit packed-refs file: %s",
                            strerror(errno));
                ret = TRANSACTION_GENERIC_ERROR;
@@@ -3956,16 -3984,13 +3968,16 @@@ static int expire_reflog_ent(unsigned c
        return 0;
  }
  
 -int reflog_expire(const char *refname, const unsigned char *sha1,
 -               unsigned int flags,
 -               reflog_expiry_prepare_fn prepare_fn,
 -               reflog_expiry_should_prune_fn should_prune_fn,
 -               reflog_expiry_cleanup_fn cleanup_fn,
 -               void *policy_cb_data)
 +static int files_reflog_expire(struct ref_store *ref_store,
 +                             const char *refname, const unsigned char *sha1,
 +                             unsigned int flags,
 +                             reflog_expiry_prepare_fn prepare_fn,
 +                             reflog_expiry_should_prune_fn should_prune_fn,
 +                             reflog_expiry_cleanup_fn cleanup_fn,
 +                             void *policy_cb_data)
  {
 +      struct files_ref_store *refs =
 +              files_downcast(ref_store, 0, "reflog_expire");
        static struct lock_file reflog_lock;
        struct expire_reflog_cb cb;
        struct ref_lock *lock;
         * reference itself, plus we might need to update the
         * reference if --updateref was specified:
         */
 -      lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, REF_NODEREF,
 +      lock = lock_ref_sha1_basic(refs, refname, sha1,
 +                                 NULL, NULL, REF_NODEREF,
                                   &type, &err);
        if (!lock) {
                error("cannot lock ref '%s': %s", refname, err.buf);
        unlock_ref(lock);
        return -1;
  }
 +
 +static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 +{
 +      /* Check validity (but we don't need the result): */
 +      files_downcast(ref_store, 0, "init_db");
 +
 +      /*
 +       * Create .git/refs/{heads,tags}
 +       */
 +      safe_create_dir(git_path("refs/heads"), 1);
 +      safe_create_dir(git_path("refs/tags"), 1);
 +      if (get_shared_repository()) {
 +              adjust_shared_perm(git_path("refs/heads"));
 +              adjust_shared_perm(git_path("refs/tags"));
 +      }
 +      return 0;
 +}
 +
 +struct ref_storage_be refs_be_files = {
 +      NULL,
 +      "files",
 +      files_ref_store_create,
 +      files_init_db,
 +      files_transaction_commit,
 +      files_initial_transaction_commit,
 +
 +      files_pack_refs,
 +      files_peel_ref,
 +      files_create_symref,
 +      files_delete_refs,
 +      files_rename_ref,
 +
 +      files_ref_iterator_begin,
 +      files_read_raw_ref,
 +      files_verify_refname_available,
 +
 +      files_reflog_iterator_begin,
 +      files_for_each_reflog_ent,
 +      files_for_each_reflog_ent_reverse,
 +      files_reflog_exists,
 +      files_create_reflog,
 +      files_delete_reflog,
 +      files_reflog_expire
 +};