Fix v1_ShardInfo mem layout

v1_ShardInfo should have the same byte alignment as ShardInfo struct.

Author: koujl

conanfile.py

@@ -10,7 +10,7 @@
 
 class HomeObjectConan(ConanFile):
     name = "homeobject"
-    version = "4.0.7"
+    version = "4.0.8"
 
     homepage = "https://github.com/eBay/HomeObject"
     description = "Blob Store built on HomeStore"

src/lib/homestore_backend/hs_homeobject.hpp

@@ -95,6 +95,21 @@ class HSHomeObject : public HomeObjectImpl {
     std::vector< shard_id_t > shards_to_migrate_;
 
 public:
+    // Old version shard_info_superblk (v0.01) - for backward compatibility testing and migration
+    // v1 ShardInfo did not have the meta field
+    struct v1_ShardInfo {
+        shard_id_t id;
+        pg_id_t placement_group;
+        ShardInfo::State state;
+        uint64_t lsn;
+        uint64_t created_time;
+        uint64_t last_modified_time;
+        uint64_t available_capacity_bytes;
+        uint64_t total_capacity_bytes;
+        std::optional< peer_id_t > current_leader{std::nullopt};
+        // Note: meta field was added in v2
+    };
+
 #pragma pack(1)
     struct pg_members {
         peer_id_t id;
@@ -193,21 +208,6 @@ class HSHomeObject : public HomeObjectImpl {
         bool valid() const { return DataHeader::valid() && sb_version <= shard_sb_version; }
     };
 
-    // Old version shard_info_superblk (v0.01) - for backward compatibility testing and migration
-    // v1 ShardInfo did not have the meta field
-    struct v1_ShardInfo {
-        shard_id_t id;
-        pg_id_t placement_group;
-        ShardInfo::State state;
-        uint64_t lsn;
-        uint64_t created_time;
-        uint64_t last_modified_time;
-        uint64_t available_capacity_bytes;
-        uint64_t total_capacity_bytes;
-        std::optional< peer_id_t > current_leader{std::nullopt};
-        // Note: meta field was added in v2
-    };
-
     struct v1_shard_info_superblk : DataHeader {
         v1_ShardInfo info;
         homestore::chunk_num_t p_chunk_id{0};