return -1;
}
- ret = ref_transaction_create(data->transaction, refname, oid,
+struct migration_data {
+ struct ref_store *old_refs;
+ struct ref_transaction *transaction;
+ struct strbuf *errbuf;
+};
+
+static int migrate_one_ref(const char *refname, const struct object_id *oid,
+ int flags, void *cb_data)
+{
+ struct migration_data *data = cb_data;
+ struct strbuf symref_target = STRBUF_INIT;
+ int ret;
+
+ if (flags & REF_ISSYMREF) {
+ ret = refs_read_symbolic_ref(data->old_refs, refname, &symref_target);
+ if (ret < 0)
+ goto done;
+
+ ret = ref_transaction_update(data->transaction, refname, NULL, null_oid(),
+ symref_target.buf, NULL,
+ REF_SKIP_CREATE_REFLOG | REF_NO_DEREF, NULL, data->errbuf);
+ if (ret < 0)
+ goto done;
+ } else {
++ ret = ref_transaction_create(data->transaction, refname, oid, NULL,
+ REF_SKIP_CREATE_REFLOG | REF_SKIP_OID_VERIFICATION,
+ NULL, data->errbuf);
+ if (ret < 0)
+ goto done;
+ }
+
+done:
+ strbuf_release(&symref_target);
+ return ret;
+}
+
+static int move_files(const char *from_path, const char *to_path, struct strbuf *errbuf)
+{
+ struct strbuf from_buf = STRBUF_INIT, to_buf = STRBUF_INIT;
+ size_t from_len, to_len;
+ DIR *from_dir;
+ int ret;
+
+ from_dir = opendir(from_path);
+ if (!from_dir) {
+ strbuf_addf(errbuf, "could not open source directory '%s': %s",
+ from_path, strerror(errno));
+ ret = -1;
+ goto done;
+ }
+
+ strbuf_addstr(&from_buf, from_path);
+ strbuf_complete(&from_buf, '/');
+ from_len = from_buf.len;
+
+ strbuf_addstr(&to_buf, to_path);
+ strbuf_complete(&to_buf, '/');
+ to_len = to_buf.len;
+
+ while (1) {
+ struct dirent *ent;
+
+ errno = 0;
+ ent = readdir(from_dir);
+ if (!ent)
+ break;
+
+ if (!strcmp(ent->d_name, ".") ||
+ !strcmp(ent->d_name, ".."))
+ continue;
+
+ strbuf_setlen(&from_buf, from_len);
+ strbuf_addstr(&from_buf, ent->d_name);
+
+ strbuf_setlen(&to_buf, to_len);
+ strbuf_addstr(&to_buf, ent->d_name);
+
+ ret = rename(from_buf.buf, to_buf.buf);
+ if (ret < 0) {
+ strbuf_addf(errbuf, "could not link file '%s' to '%s': %s",
+ from_buf.buf, to_buf.buf, strerror(errno));
+ goto done;
+ }
+ }
+
+ if (errno) {
+ strbuf_addf(errbuf, "could not read entry from directory '%s': %s",
+ from_path, strerror(errno));
+ ret = -1;
+ goto done;
+ }
+
+ ret = 0;
+
+done:
+ strbuf_release(&from_buf);
+ strbuf_release(&to_buf);
+ if (from_dir)
+ closedir(from_dir);
+ return ret;
+}
+
+static int count_reflogs(const char *reflog UNUSED, void *payload)
+{
+ size_t *reflog_count = payload;
+ (*reflog_count)++;
+ return 0;
+}
+
+static int has_worktrees(void)
+{
+ struct worktree **worktrees = get_worktrees();
+ int ret = 0;
+ size_t i;
+
+ for (i = 0; worktrees[i]; i++) {
+ if (is_main_worktree(worktrees[i]))
+ continue;
+ ret = 1;
+ }
+
+ free_worktrees(worktrees);
+ return ret;
+}
+
+int repo_migrate_ref_storage_format(struct repository *repo,
+ enum ref_storage_format format,
+ unsigned int flags,
+ struct strbuf *errbuf)
+{
+ struct ref_store *old_refs = NULL, *new_refs = NULL;
+ struct ref_transaction *transaction = NULL;
+ struct strbuf new_gitdir = STRBUF_INIT;
+ struct migration_data data;
+ size_t reflog_count = 0;
+ int did_migrate_refs = 0;
+ int ret;
+
+ if (repo->ref_storage_format == format) {
+ strbuf_addstr(errbuf, "current and new ref storage format are equal");
+ ret = -1;
+ goto done;
+ }
+
+ old_refs = get_main_ref_store(repo);
+
+ /*
+ * We do not have any interfaces that would allow us to write many
+ * reflog entries. Once we have them we can remove this restriction.
+ */
+ if (refs_for_each_reflog(old_refs, count_reflogs, &reflog_count) < 0) {
+ strbuf_addstr(errbuf, "cannot count reflogs");
+ ret = -1;
+ goto done;
+ }
+ if (reflog_count) {
+ strbuf_addstr(errbuf, "migrating reflogs is not supported yet");
+ ret = -1;
+ goto done;
+ }
+
+ /*
+ * Worktrees complicate the migration because every worktree has a
+ * separate ref storage. While it should be feasible to implement, this
+ * is pushed out to a future iteration.
+ *
+ * TODO: we should really be passing the caller-provided repository to
+ * `has_worktrees()`, but our worktree subsystem doesn't yet support
+ * that.
+ */
+ if (has_worktrees()) {
+ strbuf_addstr(errbuf, "migrating repositories with worktrees is not supported yet");
+ ret = -1;
+ goto done;
+ }
+
+ /*
+ * The overall logic looks like this:
+ *
+ * 1. Set up a new temporary directory and initialize it with the new
+ * format. This is where all refs will be migrated into.
+ *
+ * 2. Enumerate all refs and write them into the new ref storage.
+ * This operation is safe as we do not yet modify the main
+ * repository.
+ *
+ * 3. If we're in dry-run mode then we are done and can hand over the
+ * directory to the caller for inspection. If not, we now start
+ * with the destructive part.
+ *
+ * 4. Delete the old ref storage from disk. As we have a copy of refs
+ * in the new ref storage it's okay(ish) if we now get interrupted
+ * as there is an equivalent copy of all refs available.
+ *
+ * 5. Move the new ref storage files into place.
+ *
+ * 6. Change the repository format to the new ref format.
+ */
+ strbuf_addf(&new_gitdir, "%s/%s", old_refs->gitdir, "ref_migration.XXXXXX");
+ if (!mkdtemp(new_gitdir.buf)) {
+ strbuf_addf(errbuf, "cannot create migration directory: %s",
+ strerror(errno));
+ ret = -1;
+ goto done;
+ }
+
+ new_refs = ref_store_init(repo, format, new_gitdir.buf,
+ REF_STORE_ALL_CAPS);
+ ret = ref_store_create_on_disk(new_refs, 0, errbuf);
+ if (ret < 0)
+ goto done;
+
+ transaction = ref_store_transaction_begin(new_refs, errbuf);
+ if (!transaction)
+ goto done;
+
+ data.old_refs = old_refs;
+ data.transaction = transaction;
+ data.errbuf = errbuf;
+
+ /*
+ * We need to use the internal `do_for_each_ref()` here so that we can
+ * also include broken refs and symrefs. These would otherwise be
+ * skipped silently.
+ *
+ * Ideally, we would do this call while locking the old ref storage
+ * such that there cannot be any concurrent modifications. We do not
+ * have the infra for that though, and the "files" backend does not
+ * allow for a central lock due to its design. It's thus on the user to
+ * ensure that there are no concurrent writes.
+ */
+ ret = do_for_each_ref(old_refs, "", NULL, migrate_one_ref, 0,
+ DO_FOR_EACH_INCLUDE_ROOT_REFS | DO_FOR_EACH_INCLUDE_BROKEN,
+ &data);
+ if (ret < 0)
+ goto done;
+
+ /*
+ * TODO: we might want to migrate to `initial_ref_transaction_commit()`
+ * here, which is more efficient for the files backend because it would
+ * write new refs into the packed-refs file directly. At this point,
+ * the files backend doesn't handle pseudo-refs and symrefs correctly
+ * though, so this requires some more work.
+ */
+ ret = ref_transaction_commit(transaction, errbuf);
+ if (ret < 0)
+ goto done;
+ did_migrate_refs = 1;
+
+ if (flags & REPO_MIGRATE_REF_STORAGE_FORMAT_DRYRUN) {
+ printf(_("Finished dry-run migration of refs, "
+ "the result can be found at '%s'\n"), new_gitdir.buf);
+ ret = 0;
+ goto done;
+ }
+
+ /*
+ * Until now we were in the non-destructive phase, where we only
+ * populated the new ref store. From hereon though we are about
+ * to get hands by deleting the old ref store and then moving
+ * the new one into place.
+ *
+ * Assuming that there were no concurrent writes, the new ref
+ * store should have all information. So if we fail from hereon
+ * we may be in an in-between state, but it would still be able
+ * to recover by manually moving remaining files from the
+ * temporary migration directory into place.
+ */
+ ret = ref_store_remove_on_disk(old_refs, errbuf);
+ if (ret < 0)
+ goto done;
+
+ ret = move_files(new_gitdir.buf, old_refs->gitdir, errbuf);
+ if (ret < 0)
+ goto done;
+
+ if (rmdir(new_gitdir.buf) < 0)
+ warning_errno(_("could not remove temporary migration directory '%s'"),
+ new_gitdir.buf);
+
+ /*
+ * We have migrated the repository, so we now need to adjust the
+ * repository format so that clients will use the new ref store.
+ * We also need to swap out the repository's main ref store.
+ */
+ initialize_repository_version(hash_algo_by_ptr(repo->hash_algo), format, 1);
+
+ free(new_refs->gitdir);
+ new_refs->gitdir = xstrdup(old_refs->gitdir);
+ repo->refs_private = new_refs;
+ ref_store_release(old_refs);
+
+ ret = 0;
+
+done:
+ if (ret && did_migrate_refs) {
+ strbuf_complete(errbuf, '\n');
+ strbuf_addf(errbuf, _("migrated refs can be found at '%s'"),
+ new_gitdir.buf);
+ }
+
+ if (ret && new_refs)
+ ref_store_release(new_refs);
+ ref_transaction_free(transaction);
+ strbuf_release(&new_gitdir);
+ return ret;
+}
++
+ int ref_update_expects_existing_old_ref(struct ref_update *update)
+ {
+ return (update->flags & REF_HAVE_OLD) &&
+ (!is_null_oid(&update->old_oid) || update->old_target);
+ }
++
projects / thirdparty / git.git / commitdiff
