Make ingest external file backward compatible

Summary: Closes https://github.com/facebook/rocksdb/pull/1783

Differential Revision: D4443463

Pulled By: IslamAbdelRahman

fbshipit-source-id: 39d21d6

db/external_sst_file_ingestion_job.cc

@@ -306,8 +306,16 @@ Status ExternalSstFileIngestionJob::GetIngestedFileInfo(
     if (file_to_ingest->global_seqno_offset == 0) {
       return Status::Corruption("Was not able to find file global seqno field");
     }
+  } else if (file_to_ingest->version == 1) {
+    // SST file V1 should not have global seqno field
+    assert(seqno_iter == uprops.end());
+    if (ingestion_options_.allow_blocking_flush ||
+            ingestion_options_.allow_global_seqno) {
+      return Status::InvalidArgument(
+            "External SST file V1 does not support global seqno");
+    }
   } else {
-    return Status::InvalidArgument("external file version is not supported");
+    return Status::InvalidArgument("External file version is not supported");
   }
   // Get number of entries in table
   file_to_ingest->num_entries = props->num_entries;