diff --git a/Makefile b/Makefile
index 8efe430e2..9ee9bcd2a 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ clean:
 	rm -f *.o
 crc32c.o: crc32c.c
 	g++ $(CXXFLAGS) -c -o $@ $<
-%.o: %.cpp allocator.h blockstore_flush.h blockstore.h blockstore_impl.h blockstore_init.h blockstore_journal.h crc32c.h ringloop.h xor.h timerfd_interval.h
+%.o: %.cpp allocator.h blockstore_flush.h blockstore.h blockstore_impl.h blockstore_init.h blockstore_journal.h crc32c.h ringloop.h xor.h timerfd_interval.h object_id.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 osd: $(BLOCKSTORE_OBJS) osd_main.cpp osd.h osd_ops.h osd.o
 	g++ $(CXXFLAGS) -ltcmalloc_minimal -luring -o osd osd_main.cpp osd.o $(BLOCKSTORE_OBJS)
diff --git a/blockstore.h b/blockstore.h
index f68d01a7d..96c471224 100644
--- a/blockstore.h
+++ b/blockstore.h
@@ -10,6 +10,7 @@
 #include <unordered_map>
 #include <functional>
 
+#include "object_id.h"
 #include "ringloop.h"
 
 // Default block size is 128 KB, current allowed range is 4K - 128M
@@ -18,56 +19,6 @@
 #define MAX_BLOCK_SIZE 128*1024*1024
 #define DISK_ALIGNMENT 512
 
-// 16 bytes per object/stripe id
-// stripe includes replica number in 4 least significant bits
-struct __attribute__((__packed__)) object_id
-{
-    uint64_t inode;
-    uint64_t stripe;
-};
-
-inline bool operator == (const object_id & a, const object_id & b)
-{
-    return a.inode == b.inode && a.stripe == b.stripe;
-}
-
-inline bool operator != (const object_id & a, const object_id & b)
-{
-    return a.inode != b.inode || a.stripe != b.stripe;
-}
-
-inline bool operator < (const object_id & a, const object_id & b)
-{
-    return a.inode < b.inode || a.inode == b.inode && a.stripe < b.stripe;
-}
-
-// 56 = 24 + 32 bytes per dirty entry in memory (obj_ver_id => dirty_entry)
-struct __attribute__((__packed__)) obj_ver_id
-{
-    object_id oid;
-    uint64_t version;
-};
-
-inline bool operator < (const obj_ver_id & a, const obj_ver_id & b)
-{
-    return a.oid < b.oid || a.oid == b.oid && a.version < b.version;
-}
-
-namespace std
-{
-    template<> struct hash<object_id>
-    {
-        inline size_t operator()(const object_id &s) const
-        {
-            size_t seed = 0;
-            // Copy-pasted from spp::hash_combine()
-            seed ^= (s.inode + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
-            seed ^= (s.stripe + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
-            return seed;
-        }
-    };
-}
-
 #define OP_READ 1
 #define OP_WRITE 2
 #define OP_SYNC 3
diff --git a/object_id.h b/object_id.h
new file mode 100644
index 000000000..0a99c9f20
--- /dev/null
+++ b/object_id.h
@@ -0,0 +1,53 @@
+#pragma once
+
+#include <stdint.h>
+
+// 16 bytes per object/stripe id
+// stripe includes replica number in 4 least significant bits
+struct __attribute__((__packed__)) object_id
+{
+    uint64_t inode;
+    uint64_t stripe;
+};
+
+inline bool operator == (const object_id & a, const object_id & b)
+{
+    return a.inode == b.inode && a.stripe == b.stripe;
+}
+
+inline bool operator != (const object_id & a, const object_id & b)
+{
+    return a.inode != b.inode || a.stripe != b.stripe;
+}
+
+inline bool operator < (const object_id & a, const object_id & b)
+{
+    return a.inode < b.inode || a.inode == b.inode && a.stripe < b.stripe;
+}
+
+// 56 = 24 + 32 bytes per dirty entry in memory (obj_ver_id => dirty_entry)
+struct __attribute__((__packed__)) obj_ver_id
+{
+    object_id oid;
+    uint64_t version;
+};
+
+inline bool operator < (const obj_ver_id & a, const obj_ver_id & b)
+{
+    return a.oid < b.oid || a.oid == b.oid && a.version < b.version;
+}
+
+namespace std
+{
+    template<> struct hash<object_id>
+    {
+        inline size_t operator()(const object_id &s) const
+        {
+            size_t seed = 0;
+            // Copy-pasted from spp::hash_combine()
+            seed ^= (s.inode + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
+            seed ^= (s.stripe + 0xc6a4a7935bd1e995 + (seed << 6) + (seed >> 2));
+            return seed;
+        }
+    };
+}
diff --git a/osd.h b/osd.h
index d0788ba18..76acd7547 100644
--- a/osd.h
+++ b/osd.h
@@ -12,6 +12,7 @@
 #include <unordered_map>
 #include <deque>
 
+#include "blockstore.h"
 #include "ringloop.h"
 #include "osd_ops.h"
 
diff --git a/osd_ops.h b/osd_ops.h
index 3f99f3d33..2f339c11d 100644
--- a/osd_ops.h
+++ b/osd_ops.h
@@ -1,7 +1,6 @@
 #pragma once
 
-#include "blockstore.h"
-#include <stdint.h>
+#include "object_id.h"
 
 // Magic numbers
 #define SECONDARY_OSD_OP_MAGIC      0x2bd7b10325434553l