diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
index bcd85c1976..28d1fee505 100644
--- a/Documentation/git-commit-graph.txt
+++ b/Documentation/git-commit-graph.txt
@@ -26,7 +26,10 @@ OPTIONS
 	file. This parameter exists to specify the location of an alternate
 	that only has the objects directory, not a full `.git` directory. The
 	commit-graph file is expected to be in the `<dir>/info` directory and
-	the packfiles are expected to be in `<dir>/pack`.
+	the packfiles are expected to be in `<dir>/pack`. If the directory
+	could not be made into an absolute path, or does not match any known
+	object directory, `git commit-graph ...` will exit with non-zero
+	status.
 
 --[no-]progress::
 	Turn progress on/off explicitly. If neither is specified, progress is
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index e0c6fc4bbf..20a3d31b76 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -34,9 +34,29 @@ static struct opts_commit_graph {
 	int progress;
 } opts;
 
+static struct object_directory *find_odb(struct repository *r,
+					 const char *obj_dir)
+{
+	struct object_directory *odb;
+	char *obj_dir_real = real_pathdup(obj_dir, 1);
+
+	prepare_alt_odb(r);
+	for (odb = r->objects->odb; odb; odb = odb->next) {
+		if (!strcmp(obj_dir_real, real_path(odb->path)))
+			break;
+	}
+
+	free(obj_dir_real);
+
+	if (!odb)
+		die(_("could not find object directory matching %s"), obj_dir);
+	return odb;
+}
+
 static int graph_verify(int argc, const char **argv)
 {
 	struct commit_graph *graph = NULL;
+	struct object_directory *odb = NULL;
 	char *graph_name;
 	int open_ok;
 	int fd;
@@ -67,7 +87,8 @@ static int graph_verify(int argc, const char **argv)
 	if (opts.progress)
 		flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
-	graph_name = get_commit_graph_filename(opts.obj_dir);
+	odb = find_odb(the_repository, opts.obj_dir);
+	graph_name = get_commit_graph_filename(odb->path);
 	open_ok = open_commit_graph(graph_name, &fd, &st);
 	if (!open_ok && errno != ENOENT)
 		die_errno(_("Could not open commit-graph '%s'"), graph_name);
@@ -76,8 +97,8 @@ static int graph_verify(int argc, const char **argv)
 
 	if (open_ok)
 		graph = load_commit_graph_one_fd_st(fd, &st);
-	 else
-		graph = read_commit_graph_one(the_repository, opts.obj_dir);
+	else
+		graph = read_commit_graph_one(the_repository, odb->path);
 
 	/* Return failure if open_ok predicted success */
 	if (!graph)
@@ -94,6 +115,7 @@ static int graph_write(int argc, const char **argv)
 {
 	struct string_list *pack_indexes = NULL;
 	struct string_list *commit_hex = NULL;
+	struct object_directory *odb = NULL;
 	struct string_list lines;
 	int result = 0;
 	enum commit_graph_write_flags flags = 0;
@@ -145,9 +167,10 @@ static int graph_write(int argc, const char **argv)
 		flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
 	read_replace_refs = 0;
+	odb = find_odb(the_repository, opts.obj_dir);
 
 	if (opts.reachable) {
-		if (write_commit_graph_reachable(opts.obj_dir, flags, &split_opts))
+		if (write_commit_graph_reachable(odb, flags, &split_opts))
 			return 1;
 		return 0;
 	}
@@ -169,7 +192,7 @@ static int graph_write(int argc, const char **argv)
 		UNLEAK(buf);
 	}
 
-	if (write_commit_graph(opts.obj_dir,
+	if (write_commit_graph(odb,
 			       pack_indexes,
 			       commit_hex,
 			       flags,
diff --git a/builtin/commit.c b/builtin/commit.c
index aa1332308a..543a8e0bd2 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1688,7 +1688,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		      "not exceeded, and then \"git restore --staged :/\" to recover."));
 
 	if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
-	    write_commit_graph_reachable(get_object_directory(), 0, NULL))
+	    write_commit_graph_reachable(the_repository->objects->odb, 0, NULL))
 		return 1;
 
 	repo_rerere(the_repository, 0);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index b4c6d921d0..1ce16c96e9 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1870,7 +1870,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		if (progress)
 			commit_graph_flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
-		write_commit_graph_reachable(get_object_directory(),
+		write_commit_graph_reachable(the_repository->objects->odb,
 					     commit_graph_flags,
 					     NULL);
 	}
diff --git a/builtin/gc.c b/builtin/gc.c
index 3f76bf4aa7..8e0b9cf41b 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -686,7 +686,7 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 
 	prepare_repo_settings(the_repository);
 	if (the_repository->settings.gc_write_commit_graph == 1)
-		write_commit_graph_reachable(get_object_directory(),
+		write_commit_graph_reachable(the_repository->objects->odb,
 					     !quiet && !daemonized ? COMMIT_GRAPH_WRITE_PROGRESS : 0,
 					     NULL);
 
diff --git a/commit-graph.c b/commit-graph.c
index b205e65ed1..cbfeece112 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -772,7 +772,7 @@ struct packed_oid_list {
 
 struct write_commit_graph_context {
 	struct repository *r;
-	char *obj_dir;
+	struct object_directory *odb;
 	char *graph_name;
 	struct packed_oid_list oids;
 	struct packed_commit_list commits;
@@ -1149,7 +1149,7 @@ static int add_ref_to_list(const char *refname,
 	return 0;
 }
 
-int write_commit_graph_reachable(const char *obj_dir,
+int write_commit_graph_reachable(struct object_directory *odb,
 				 enum commit_graph_write_flags flags,
 				 const struct split_commit_graph_opts *split_opts)
 {
@@ -1157,7 +1157,7 @@ int write_commit_graph_reachable(const char *obj_dir,
 	int result;
 
 	for_each_ref(add_ref_to_list, &list);
-	result = write_commit_graph(obj_dir, NULL, &list,
+	result = write_commit_graph(odb, NULL, &list,
 				    flags, split_opts);
 
 	string_list_clear(&list, 0);
@@ -1172,7 +1172,7 @@ static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
 	struct strbuf packname = STRBUF_INIT;
 	int dirlen;
 
-	strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
+	strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
 	dirlen = packname.len;
 	if (ctx->report_progress) {
 		strbuf_addf(&progress_title,
@@ -1368,10 +1368,10 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 
 		strbuf_addf(&tmp_file,
 			    "%s/info/commit-graphs/tmp_graph_XXXXXX",
-			    ctx->obj_dir);
+			    ctx->odb->path);
 		ctx->graph_name = strbuf_detach(&tmp_file, NULL);
 	} else {
-		ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
+		ctx->graph_name = get_commit_graph_filename(ctx->odb->path);
 	}
 
 	if (safe_create_leading_directories(ctx->graph_name)) {
@@ -1382,7 +1382,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 	}
 
 	if (ctx->split) {
-		char *lock_name = get_chain_filename(ctx->obj_dir);
+		char *lock_name = get_chain_filename(ctx->odb->path);
 
 		hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
 
@@ -1506,12 +1506,12 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 				}
 			}
 		} else {
-			char *graph_name = get_commit_graph_filename(ctx->obj_dir);
+			char *graph_name = get_commit_graph_filename(ctx->odb->path);
 			unlink(graph_name);
 		}
 
 		ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
-		final_graph_name = get_split_graph_filename(ctx->obj_dir,
+		final_graph_name = get_split_graph_filename(ctx->odb->path,
 					ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
 		ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
 
@@ -1553,7 +1553,7 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
 
 	while (g && (g->num_commits <= size_mult * num_commits ||
 		    (max_commits && num_commits > max_commits))) {
-		if (strcmp(g->obj_dir, ctx->obj_dir))
+		if (strcmp(g->obj_dir, ctx->odb->path))
 			break;
 
 		num_commits += g->num_commits;
@@ -1568,7 +1568,7 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
 		char *old_graph_name = get_commit_graph_filename(g->obj_dir);
 
 		if (!strcmp(g->filename, old_graph_name) &&
-		    strcmp(g->obj_dir, ctx->obj_dir)) {
+		    strcmp(g->obj_dir, ctx->odb->path)) {
 			ctx->num_commit_graphs_after = 1;
 			ctx->new_base_graph = NULL;
 		}
@@ -1719,13 +1719,13 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx)
 	if (ctx->split_opts && ctx->split_opts->expire_time)
 		expire_time -= ctx->split_opts->expire_time;
 	if (!ctx->split) {
-		char *chain_file_name = get_chain_filename(ctx->obj_dir);
+		char *chain_file_name = get_chain_filename(ctx->odb->path);
 		unlink(chain_file_name);
 		free(chain_file_name);
 		ctx->num_commit_graphs_after = 0;
 	}
 
-	strbuf_addstr(&path, ctx->obj_dir);
+	strbuf_addstr(&path, ctx->odb->path);
 	strbuf_addstr(&path, "/info/commit-graphs");
 	dir = opendir(path.buf);
 
@@ -1764,7 +1764,7 @@ out:
 	strbuf_release(&path);
 }
 
-int write_commit_graph(const char *obj_dir,
+int write_commit_graph(struct object_directory *odb,
 		       struct string_list *pack_indexes,
 		       struct string_list *commit_hex,
 		       enum commit_graph_write_flags flags,
@@ -1772,7 +1772,6 @@ int write_commit_graph(const char *obj_dir,
 {
 	struct write_commit_graph_context *ctx;
 	uint32_t i, count_distinct = 0;
-	size_t len;
 	int res = 0;
 
 	if (!commit_graph_compatible(the_repository))
@@ -1780,14 +1779,7 @@ int write_commit_graph(const char *obj_dir,
 
 	ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
 	ctx->r = the_repository;
-
-	/* normalize object dir with no trailing slash */
-	ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
-	normalize_path_copy(ctx->obj_dir, obj_dir);
-	len = strlen(ctx->obj_dir);
-	if (len && ctx->obj_dir[len - 1] == '/')
-		ctx->obj_dir[len - 1] = 0;
-
+	ctx->odb = odb;
 	ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
 	ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
 	ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
@@ -1824,7 +1816,7 @@ int write_commit_graph(const char *obj_dir,
 		ctx->oids.alloc = split_opts->max_commits;
 
 	if (ctx->append) {
-		prepare_commit_graph_one(ctx->r, ctx->obj_dir);
+		prepare_commit_graph_one(ctx->r, ctx->odb->path);
 		if (ctx->r->objects->commit_graph)
 			ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
 	}
@@ -1898,7 +1890,6 @@ cleanup:
 	free(ctx->graph_name);
 	free(ctx->commits.list);
 	free(ctx->oids.list);
-	free(ctx->obj_dir);
 
 	if (ctx->commit_graph_filenames_after) {
 		for (i = 0; i < ctx->num_commit_graphs_after; i++) {
diff --git a/commit-graph.h b/commit-graph.h
index 7f5c933fa2..2a6251bd3d 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -5,6 +5,7 @@
 #include "repository.h"
 #include "string-list.h"
 #include "cache.h"
+#include "object-store.h"
 
 #define GIT_TEST_COMMIT_GRAPH "GIT_TEST_COMMIT_GRAPH"
 #define GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD"
@@ -91,10 +92,10 @@ struct split_commit_graph_opts {
  * is not compatible with the commit-graph feature, then the
  * methods will return 0 without writing a commit-graph.
  */
-int write_commit_graph_reachable(const char *obj_dir,
+int write_commit_graph_reachable(struct object_directory *odb,
 				 enum commit_graph_write_flags flags,
 				 const struct split_commit_graph_opts *split_opts);
-int write_commit_graph(const char *obj_dir,
+int write_commit_graph(struct object_directory *odb,
 		       struct string_list *pack_indexes,
 		       struct string_list *commit_hex,
 		       enum commit_graph_write_flags flags,