diff --git a/builtin/fsck.c b/builtin/fsck.c
index 55153cf92a..15338bd178 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -725,13 +725,8 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 		for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
 		for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
 	} else {
-		struct object_directory *alt_odb_list;
-
-		fsck_object_dir(get_object_directory());
-
 		prepare_alt_odb(the_repository);
-		alt_odb_list = the_repository->objects->alt_odb_list;
-		for (odb = alt_odb_list; odb; odb = odb->next)
+		for (odb = the_repository->objects->odb; odb; odb = odb->next)
 			fsck_object_dir(odb->path);
 
 		if (check_full) {
@@ -834,13 +829,8 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 		struct child_process commit_graph_verify = CHILD_PROCESS_INIT;
 		const char *verify_argv[] = { "commit-graph", "verify", NULL, NULL, NULL };
 
-		commit_graph_verify.argv = verify_argv;
-		commit_graph_verify.git_cmd = 1;
-		if (run_command(&commit_graph_verify))
-			errors_found |= ERROR_COMMIT_GRAPH;
-
 		prepare_alt_odb(the_repository);
-		for (odb = the_repository->objects->alt_odb_list; odb; odb = odb->next) {
+		for (odb = the_repository->objects->odb; odb; odb = odb->next) {
 			child_process_init(&commit_graph_verify);
 			commit_graph_verify.argv = verify_argv;
 			commit_graph_verify.git_cmd = 1;
@@ -855,13 +845,8 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 		struct child_process midx_verify = CHILD_PROCESS_INIT;
 		const char *midx_argv[] = { "multi-pack-index", "verify", NULL, NULL, NULL };
 
-		midx_verify.argv = midx_argv;
-		midx_verify.git_cmd = 1;
-		if (run_command(&midx_verify))
-			errors_found |= ERROR_COMMIT_GRAPH;
-
 		prepare_alt_odb(the_repository);
-		for (odb = the_repository->objects->alt_odb_list; odb; odb = odb->next) {
+		for (odb = the_repository->objects->odb; odb; odb = odb->next) {
 			child_process_init(&midx_verify);
 			midx_verify.argv = midx_argv;
 			midx_verify.git_cmd = 1;
diff --git a/builtin/grep.c b/builtin/grep.c
index d8508ddf79..714c8d91ba 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -441,7 +441,7 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 	 * object.
 	 */
 	grep_read_lock();
-	add_to_alternates_memory(submodule.objects->objectdir);
+	add_to_alternates_memory(submodule.objects->odb->path);
 	grep_read_unlock();
 
 	if (oid) {
diff --git a/commit-graph.c b/commit-graph.c
index 5dd3f5b15c..99163c244b 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -231,7 +231,6 @@ static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 static int prepare_commit_graph(struct repository *r)
 {
 	struct object_directory *odb;
-	char *obj_dir;
 	int config_value;
 
 	if (r->objects->commit_graph_attempted)
@@ -252,10 +251,8 @@ static int prepare_commit_graph(struct repository *r)
 	if (!commit_graph_compatible(r))
 		return 0;
 
-	obj_dir = r->objects->objectdir;
-	prepare_commit_graph_one(r, obj_dir);
 	prepare_alt_odb(r);
-	for (odb = r->objects->alt_odb_list;
+	for (odb = r->objects->odb;
 	     !r->objects->commit_graph && odb;
 	     odb = odb->next)
 		prepare_commit_graph_one(r, odb->path);
diff --git a/environment.c b/environment.c
index 3f3c8746c2..441ce56690 100644
--- a/environment.c
+++ b/environment.c
@@ -274,9 +274,9 @@ const char *get_git_work_tree(void)
 
 char *get_object_directory(void)
 {
-	if (!the_repository->objects->objectdir)
+	if (!the_repository->objects->odb)
 		BUG("git environment hasn't been setup");
-	return the_repository->objects->objectdir;
+	return the_repository->objects->odb->path;
 }
 
 int odb_mkstemp(struct strbuf *temp_filename, const char *pattern)
diff --git a/object-store.h b/object-store.h
index b2fa0d0df0..30faf7b391 100644
--- a/object-store.h
+++ b/object-store.h
@@ -24,19 +24,14 @@ struct object_directory {
 	 * Path to the alternative object store. If this is a relative path,
 	 * it is relative to the current working directory.
 	 */
-	char path[FLEX_ARRAY];
+	char *path;
 };
+
 void prepare_alt_odb(struct repository *r);
 char *compute_alternate_path(const char *path, struct strbuf *err);
 typedef int alt_odb_fn(struct object_directory *, void *);
 int foreach_alt_odb(alt_odb_fn, void*);
 
-/*
- * Allocate a "struct alternate_object_database" but do _not_ actually
- * add it to the list of alternates.
- */
-struct object_directory *alloc_alt_odb(const char *dir);
-
 /*
  * Add the directory to the on-disk alternates file; the new entry will also
  * take effect in the current process.
@@ -80,17 +75,21 @@ struct multi_pack_index;
 
 struct raw_object_store {
 	/*
-	 * Path to the repository's object store.
-	 * Cannot be NULL after initialization.
+	 * Set of all object directories; the main directory is first (and
+	 * cannot be NULL after initialization). Subsequent directories are
+	 * alternates.
 	 */
-	char *objectdir;
+	struct object_directory *odb;
+	struct object_directory **odb_tail;
+	int loaded_alternates;
 
-	/* Path to extra alternate object database if not NULL */
+	/*
+	 * A list of alternate object directories loaded from the environment;
+	 * this should not generally need to be accessed directly, but will
+	 * populate the "odb" list when prepare_alt_odb() is run.
+	 */
 	char *alternate_db;
 
-	struct object_directory *alt_odb_list;
-	struct object_directory **alt_odb_tail;
-
 	/*
 	 * Objects that should be substituted by other objects
 	 * (see git-replace(1)).
diff --git a/object.c b/object.c
index dd485ac629..79d636091c 100644
--- a/object.c
+++ b/object.c
@@ -482,26 +482,26 @@ struct raw_object_store *raw_object_store_new(void)
 	return o;
 }
 
-static void free_alt_odb(struct object_directory *odb)
+static void free_object_directory(struct object_directory *odb)
 {
+	free(odb->path);
 	oid_array_clear(&odb->loose_objects_cache);
 	free(odb);
 }
 
-static void free_alt_odbs(struct raw_object_store *o)
+static void free_object_directories(struct raw_object_store *o)
 {
-	while (o->alt_odb_list) {
+	while (o->odb) {
 		struct object_directory *next;
 
-		next = o->alt_odb_list->next;
-		free_alt_odb(o->alt_odb_list);
-		o->alt_odb_list = next;
+		next = o->odb->next;
+		free_object_directory(o->odb);
+		o->odb = next;
 	}
 }
 
 void raw_object_store_clear(struct raw_object_store *o)
 {
-	FREE_AND_NULL(o->objectdir);
 	FREE_AND_NULL(o->alternate_db);
 
 	oidmap_free(o->replace_map, 1);
@@ -511,8 +511,9 @@ void raw_object_store_clear(struct raw_object_store *o)
 	o->commit_graph = NULL;
 	o->commit_graph_attempted = 0;
 
-	free_alt_odbs(o);
-	o->alt_odb_tail = NULL;
+	free_object_directories(o);
+	o->odb_tail = NULL;
+	o->loaded_alternates = 0;
 
 	INIT_LIST_HEAD(&o->packed_git_mru);
 	close_all_packs(o);
diff --git a/packfile.c b/packfile.c
index d6d511cfd2..1eda33247f 100644
--- a/packfile.c
+++ b/packfile.c
@@ -970,12 +970,12 @@ static void prepare_packed_git(struct repository *r)
 
 	if (r->objects->packed_git_initialized)
 		return;
-	prepare_multi_pack_index_one(r, r->objects->objectdir, 1);
-	prepare_packed_git_one(r, r->objects->objectdir, 1);
+
 	prepare_alt_odb(r);
-	for (odb = r->objects->alt_odb_list; odb; odb = odb->next) {
-		prepare_multi_pack_index_one(r, odb->path, 0);
-		prepare_packed_git_one(r, odb->path, 0);
+	for (odb = r->objects->odb; odb; odb = odb->next) {
+		int local = (odb == r->objects->odb);
+		prepare_multi_pack_index_one(r, odb->path, local);
+		prepare_packed_git_one(r, odb->path, local);
 	}
 	rearrange_packed_git(r);
 
diff --git a/path.c b/path.c
index ba06ec5b2d..e8609cf56d 100644
--- a/path.c
+++ b/path.c
@@ -383,7 +383,7 @@ static void adjust_git_path(const struct repository *repo,
 		strbuf_splice(buf, 0, buf->len,
 			      repo->index_file, strlen(repo->index_file));
 	else if (dir_prefix(base, "objects"))
-		replace_dir(buf, git_dir_len + 7, repo->objects->objectdir);
+		replace_dir(buf, git_dir_len + 7, repo->objects->odb->path);
 	else if (git_hooks_path && dir_prefix(base, "hooks"))
 		replace_dir(buf, git_dir_len + 5, git_hooks_path);
 	else if (repo->different_commondir)
diff --git a/repository.c b/repository.c
index 5dd1486718..7b02e1dffa 100644
--- a/repository.c
+++ b/repository.c
@@ -63,8 +63,14 @@ void repo_set_gitdir(struct repository *repo,
 	free(old_gitdir);
 
 	repo_set_commondir(repo, o->commondir);
-	expand_base_dir(&repo->objects->objectdir, o->object_dir,
+
+	if (!repo->objects->odb) {
+		repo->objects->odb = xcalloc(1, sizeof(*repo->objects->odb));
+		repo->objects->odb_tail = &repo->objects->odb->next;
+	}
+	expand_base_dir(&repo->objects->odb->path, o->object_dir,
 			repo->commondir, "objects");
+
 	free(repo->objects->alternate_db);
 	repo->objects->alternate_db = xstrdup_or_null(o->alternate_db);
 	expand_base_dir(&repo->graft_file, o->graft_file,
diff --git a/sha1-file.c b/sha1-file.c
index 15db6b61a9..503262edd2 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -346,11 +346,12 @@ static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 	}
 }
 
-static const char *odb_loose_path(const char *path, struct strbuf *buf,
+static const char *odb_loose_path(struct object_directory *odb,
+				  struct strbuf *buf,
 				  const unsigned char *sha1)
 {
 	strbuf_reset(buf);
-	strbuf_addstr(buf, path);
+	strbuf_addstr(buf, odb->path);
 	strbuf_addch(buf, '/');
 	fill_sha1_path(buf, sha1);
 	return buf->buf;
@@ -359,7 +360,7 @@ static const char *odb_loose_path(const char *path, struct strbuf *buf,
 const char *loose_object_path(struct repository *r, struct strbuf *buf,
 			      const unsigned char *sha1)
 {
-	return odb_loose_path(r->objects->objectdir, buf, sha1);
+	return odb_loose_path(r->objects->odb, buf, sha1);
 }
 
 /*
@@ -383,7 +384,7 @@ static int alt_odb_usable(struct raw_object_store *o,
 	 * Prevent the common mistake of listing the same
 	 * thing twice, or object directory itself.
 	 */
-	for (odb = o->alt_odb_list; odb; odb = odb->next) {
+	for (odb = o->odb; odb; odb = odb->next) {
 		if (!fspathcmp(path->buf, odb->path))
 			return 0;
 	}
@@ -442,11 +443,12 @@ static int link_alt_odb_entry(struct repository *r, const char *entry,
 		return -1;
 	}
 
-	ent = alloc_alt_odb(pathbuf.buf);
+	ent = xcalloc(1, sizeof(*ent));
+	ent->path = xstrdup(pathbuf.buf);
 
 	/* add the alternate entry */
-	*r->objects->alt_odb_tail = ent;
-	r->objects->alt_odb_tail = &(ent->next);
+	*r->objects->odb_tail = ent;
+	r->objects->odb_tail = &(ent->next);
 	ent->next = NULL;
 
 	/* recursively add alternates */
@@ -500,7 +502,7 @@ static void link_alt_odb_entries(struct repository *r, const char *alt,
 		return;
 	}
 
-	strbuf_add_absolute_path(&objdirbuf, r->objects->objectdir);
+	strbuf_add_absolute_path(&objdirbuf, r->objects->odb->path);
 	if (strbuf_normalize_path(&objdirbuf) < 0)
 		die(_("unable to normalize object directory: %s"),
 		    objdirbuf.buf);
@@ -535,15 +537,6 @@ static void read_info_alternates(struct repository *r,
 	free(path);
 }
 
-struct object_directory *alloc_alt_odb(const char *dir)
-{
-	struct object_directory *ent;
-
-	FLEX_ALLOC_STR(ent, path, dir);
-
-	return ent;
-}
-
 void add_to_alternates_file(const char *reference)
 {
 	struct lock_file lock = LOCK_INIT;
@@ -580,7 +573,7 @@ void add_to_alternates_file(const char *reference)
 		fprintf_or_die(out, "%s\n", reference);
 		if (commit_lock_file(&lock))
 			die_errno(_("unable to move new alternates file into place"));
-		if (the_repository->objects->alt_odb_tail)
+		if (the_repository->objects->loaded_alternates)
 			link_alt_odb_entries(the_repository, reference,
 					     '\n', NULL, 0);
 	}
@@ -680,7 +673,7 @@ int foreach_alt_odb(alt_odb_fn fn, void *cb)
 	int r = 0;
 
 	prepare_alt_odb(the_repository);
-	for (ent = the_repository->objects->alt_odb_list; ent; ent = ent->next) {
+	for (ent = the_repository->objects->odb->next; ent; ent = ent->next) {
 		r = fn(ent, cb);
 		if (r)
 			break;
@@ -690,13 +683,13 @@ int foreach_alt_odb(alt_odb_fn fn, void *cb)
 
 void prepare_alt_odb(struct repository *r)
 {
-	if (r->objects->alt_odb_tail)
+	if (r->objects->loaded_alternates)
 		return;
 
-	r->objects->alt_odb_tail = &r->objects->alt_odb_list;
 	link_alt_odb_entries(r, r->objects->alternate_db, PATH_SEP, NULL, 0);
 
-	read_info_alternates(r, r->objects->objectdir, 0);
+	read_info_alternates(r, r->objects->odb->path, 0);
+	r->objects->loaded_alternates = 1;
 }
 
 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
@@ -723,24 +716,27 @@ int check_and_freshen_file(const char *fn, int freshen)
 	return 1;
 }
 
-static int check_and_freshen_local(const struct object_id *oid, int freshen)
+static int check_and_freshen_odb(struct object_directory *odb,
+				 const struct object_id *oid,
+				 int freshen)
 {
-	static struct strbuf buf = STRBUF_INIT;
-
-	loose_object_path(the_repository, &buf, oid->hash);
+	static struct strbuf path = STRBUF_INIT;
+	odb_loose_path(odb, &path, oid->hash);
+	return check_and_freshen_file(path.buf, freshen);
+}
 
-	return check_and_freshen_file(buf.buf, freshen);
+static int check_and_freshen_local(const struct object_id *oid, int freshen)
+{
+	return check_and_freshen_odb(the_repository->objects->odb, oid, freshen);
 }
 
 static int check_and_freshen_nonlocal(const struct object_id *oid, int freshen)
 {
 	struct object_directory *odb;
-	static struct strbuf path = STRBUF_INIT;
 
 	prepare_alt_odb(the_repository);
-	for (odb = the_repository->objects->alt_odb_list; odb; odb = odb->next) {
-		odb_loose_path(odb->path, &path, oid->hash);
-		if (check_and_freshen_file(path.buf, freshen))
+	for (odb = the_repository->objects->odb->next; odb; odb = odb->next) {
+		if (check_and_freshen_odb(odb, oid, freshen))
 			return 1;
 	}
 	return 0;
@@ -889,14 +885,9 @@ static int stat_sha1_file(struct repository *r, const unsigned char *sha1,
 	struct object_directory *odb;
 	static struct strbuf buf = STRBUF_INIT;
 
-	*path = loose_object_path(r, &buf, sha1);
-	if (!lstat(*path, st))
-		return 0;
-
 	prepare_alt_odb(r);
-	errno = ENOENT;
-	for (odb = r->objects->alt_odb_list; odb; odb = odb->next) {
-		*path = odb_loose_path(odb->path, &buf, sha1);
+	for (odb = r->objects->odb; odb; odb = odb->next) {
+		*path = odb_loose_path(odb, &buf, sha1);
 		if (!lstat(*path, st))
 			return 0;
 	}
@@ -913,21 +904,16 @@ static int open_sha1_file(struct repository *r,
 {
 	int fd;
 	struct object_directory *odb;
-	int most_interesting_errno;
+	int most_interesting_errno = ENOENT;
 	static struct strbuf buf = STRBUF_INIT;
 
-	*path = loose_object_path(r, &buf, sha1);
-	fd = git_open(*path);
-	if (fd >= 0)
-		return fd;
-	most_interesting_errno = errno;
-
 	prepare_alt_odb(r);
-	for (odb = r->objects->alt_odb_list; odb; odb = odb->next) {
-		*path = odb_loose_path(odb->path, &buf, sha1);
+	for (odb = r->objects->odb; odb; odb = odb->next) {
+		*path = odb_loose_path(odb, &buf, sha1);
 		fd = git_open(*path);
 		if (fd >= 0)
 			return fd;
+
 		if (most_interesting_errno == ENOENT)
 			most_interesting_errno = errno;
 	}
@@ -2120,43 +2106,23 @@ int for_each_loose_file_in_objdir(const char *path,
 	return r;
 }
 
-struct loose_alt_odb_data {
-	each_loose_object_fn *cb;
-	void *data;
-};
-
-static int loose_from_alt_odb(struct object_directory *odb,
-			      void *vdata)
-{
-	struct loose_alt_odb_data *data = vdata;
-	struct strbuf buf = STRBUF_INIT;
-	int r;
-
-	strbuf_addstr(&buf, odb->path);
-	r = for_each_loose_file_in_objdir_buf(&buf,
-					      data->cb, NULL, NULL,
-					      data->data);
-	strbuf_release(&buf);
-	return r;
-}
-
 int for_each_loose_object(each_loose_object_fn cb, void *data,
 			  enum for_each_object_flags flags)
 {
-	struct loose_alt_odb_data alt;
-	int r;
+	struct object_directory *odb;
 
-	r = for_each_loose_file_in_objdir(get_object_directory(),
-					  cb, NULL, NULL, data);
-	if (r)
-		return r;
+	prepare_alt_odb(the_repository);
+	for (odb = the_repository->objects->odb; odb; odb = odb->next) {
+		int r = for_each_loose_file_in_objdir(odb->path, cb, NULL,
+						      NULL, data);
+		if (r)
+			return r;
 
-	if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
-		return 0;
+		if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
+			break;
+	}
 
-	alt.cb = cb;
-	alt.data = data;
-	return foreach_alt_odb(loose_from_alt_odb, &alt);
+	return 0;
 }
 
 static int check_stream_sha1(git_zstream *stream,
diff --git a/sha1-name.c b/sha1-name.c
index 96a8e71482..358ca5e288 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -96,22 +96,11 @@ static void find_short_object_filename(struct disambiguate_state *ds)
 {
 	int subdir_nr = ds->bin_pfx.hash[0];
 	struct object_directory *odb;
-	static struct object_directory *fakeent;
 	struct strbuf buf = STRBUF_INIT;
 
-	if (!fakeent) {
-		/*
-		 * Create a "fake" alternate object database that
-		 * points to our own object database, to make it
-		 * easier to get a temporary working space in
-		 * alt->name/alt->base while iterating over the
-		 * object databases including our own.
-		 */
-		fakeent = alloc_alt_odb(get_object_directory());
-	}
-	fakeent->next = the_repository->objects->alt_odb_list;
-
-	for (odb = fakeent; odb && !ds->ambiguous; odb = odb->next) {
+	for (odb = the_repository->objects->odb;
+	     odb && !ds->ambiguous;
+	     odb = odb->next) {
 		int pos;
 
 		if (!odb->loose_objects_subdir_seen[subdir_nr]) {
