diff --git a/object-file.c b/object-file.c
index ef2c7618c1..5537ab2c37 100644
--- a/object-file.c
+++ b/object-file.c
@@ -409,6 +409,7 @@ static int read_object_info_from_path(struct odb_source *source,
 	char hdr[MAX_HEADER_LEN];
 	unsigned long size_scratch;
 	enum object_type type_scratch;
+	struct stat st;
 
 	/*
 	 * If we don't care about type or size, then we don't
@@ -421,7 +422,7 @@ static int read_object_info_from_path(struct odb_source *source,
 	if (!oi || (!oi->typep && !oi->sizep && !oi->contentp)) {
 		struct stat st;
 
-		if ((!oi || !oi->disk_sizep) && (flags & OBJECT_INFO_QUICK)) {
+		if ((!oi || (!oi->disk_sizep && !oi->mtimep)) && (flags & OBJECT_INFO_QUICK)) {
 			ret = quick_has_loose(source->loose, oid) ? 0 : -1;
 			goto out;
 		}
@@ -431,8 +432,12 @@ static int read_object_info_from_path(struct odb_source *source,
 			goto out;
 		}
 
-		if (oi && oi->disk_sizep)
-			*oi->disk_sizep = st.st_size;
+		if (oi) {
+			if (oi->disk_sizep)
+				*oi->disk_sizep = st.st_size;
+			if (oi->mtimep)
+				*oi->mtimep = st.st_mtime;
+		}
 
 		ret = 0;
 		goto out;
@@ -446,7 +451,21 @@ static int read_object_info_from_path(struct odb_source *source,
 		goto out;
 	}
 
-	map = map_fd(fd, path, &mapsize);
+	if (fstat(fd, &st)) {
+		close(fd);
+		ret = -1;
+		goto out;
+	}
+
+	mapsize = xsize_t(st.st_size);
+	if (!mapsize) {
+		close(fd);
+		ret = error(_("object file %s is empty"), path);
+		goto out;
+	}
+
+	map = xmmap(NULL, mapsize, PROT_READ, MAP_PRIVATE, fd, 0);
+	close(fd);
 	if (!map) {
 		ret = -1;
 		goto out;
@@ -454,6 +473,8 @@ static int read_object_info_from_path(struct odb_source *source,
 
 	if (oi->disk_sizep)
 		*oi->disk_sizep = mapsize;
+	if (oi->mtimep)
+		*oi->mtimep = st.st_mtime;
 
 	stream_to_end = &stream;
 
diff --git a/odb.c b/odb.c
index 13a415c2c3..9d9a3fad62 100644
--- a/odb.c
+++ b/odb.c
@@ -702,6 +702,8 @@ static int do_oid_object_info_extended(struct object_database *odb,
 				oidclr(oi->delta_base_oid, odb->repo->hash_algo);
 			if (oi->contentp)
 				*oi->contentp = xmemdupz(co->buf, co->size);
+			if (oi->mtimep)
+				*oi->mtimep = 0;
 			oi->whence = OI_CACHED;
 		}
 		return 0;
diff --git a/odb.h b/odb.h
index b5d28bc188..8ad0fcc02f 100644
--- a/odb.h
+++ b/odb.h
@@ -318,6 +318,19 @@ struct object_info {
 	struct object_id *delta_base_oid;
 	void **contentp;
 
+	/*
+	 * The time the given looked-up object has been last modified.
+	 *
+	 * Note: the mtime may be ambiguous in case the object exists multiple
+	 * times in the object database. It is thus _not_ recommended to use
+	 * this field outside of contexts where you would read every instance
+	 * of the object, like for example with `odb_for_each_object()`. As it
+	 * is impossible to say at the ODB level what the intent of the caller
+	 * is (e.g. whether to find the oldest or newest object), it is the
+	 * responsibility of the caller to disambiguate the mtimes.
+	 */
+	time_t *mtimep;
+
 	/* Response */
 	enum {
 		OI_CACHED,
diff --git a/packfile.c b/packfile.c
index c54deabd64..845633139f 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1578,13 +1578,14 @@ static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
 	hashmap_add(&delta_base_cache, &ent->ent);
 }
 
-int packed_object_info(struct packed_git *p,
-		       off_t obj_offset, struct object_info *oi)
+static int packed_object_info_with_index_pos(struct packed_git *p, off_t obj_offset,
+					     uint32_t *maybe_index_pos, struct object_info *oi)
 {
 	struct pack_window *w_curs = NULL;
 	unsigned long size;
 	off_t curpos = obj_offset;
 	enum object_type type = OBJ_NONE;
+	uint32_t pack_pos;
 	int ret;
 
 	/*
@@ -1619,16 +1620,35 @@ int packed_object_info(struct packed_git *p,
 		}
 	}
 
-	if (oi->disk_sizep) {
-		uint32_t pos;
-		if (offset_to_pack_pos(p, obj_offset, &pos) < 0) {
+	if (oi->disk_sizep || (oi->mtimep && p->is_cruft)) {
+		if (offset_to_pack_pos(p, obj_offset, &pack_pos) < 0) {
 			error("could not find object at offset %"PRIuMAX" "
 			      "in pack %s", (uintmax_t)obj_offset, p->pack_name);
 			ret = -1;
 			goto out;
 		}
+	}
 
-		*oi->disk_sizep = pack_pos_to_offset(p, pos + 1) - obj_offset;
+	if (oi->disk_sizep)
+		*oi->disk_sizep = pack_pos_to_offset(p, pack_pos + 1) - obj_offset;
+
+	if (oi->mtimep) {
+		if (p->is_cruft) {
+			uint32_t index_pos;
+
+			if (load_pack_mtimes(p) < 0)
+				die(_("could not load .mtimes for cruft pack '%s'"),
+				    pack_basename(p));
+
+			if (maybe_index_pos)
+				index_pos = *maybe_index_pos;
+			else
+				index_pos = pack_pos_to_index(p, pack_pos);
+
+			*oi->mtimep = nth_packed_mtime(p, index_pos);
+		} else {
+			*oi->mtimep = p->mtime;
+		}
 	}
 
 	if (oi->typep) {
@@ -1681,6 +1701,12 @@ out:
 	return ret;
 }
 
+int packed_object_info(struct packed_git *p, off_t obj_offset,
+		       struct object_info *oi)
+{
+	return packed_object_info_with_index_pos(p, obj_offset, NULL, oi);
+}
+
 static void *unpack_compressed_entry(struct packed_git *p,
 				    struct pack_window **w_curs,
 				    off_t curpos,
@@ -2378,7 +2404,8 @@ static int packfile_store_for_each_object_wrapper(const struct object_id *oid,
 		off_t offset = nth_packed_object_offset(pack, index_pos);
 		struct object_info oi = *data->request;
 
-		if (packed_object_info(pack, offset, &oi) < 0) {
+		if (packed_object_info_with_index_pos(pack, offset,
+						      &index_pos, &oi) < 0) {
 			mark_bad_packed_object(pack, oid);
 			return -1;
 		}