diff --git a/blockstore_journal.h b/blockstore_journal.h
index 220e698c..e2ff8192 100644
--- a/blockstore_journal.h
+++ b/blockstore_journal.h
@@ -40,7 +40,8 @@ struct __attribute__((__packed__)) journal_entry_small_write
     // small_write entries contain <len> bytes of data which is stored in next sectors
     // data_offset is its offset within journal
     uint64_t data_offset;
-    // FIXME add & verify data crc32c
+    uint32_t crc32_data;
+    // FIXME verify data crc32c
 };
 
 struct __attribute__((__packed__)) journal_entry_big_write
diff --git a/blockstore_write.cpp b/blockstore_write.cpp
index 48c1c454..4a1ee476 100644
--- a/blockstore_write.cpp
+++ b/blockstore_write.cpp
@@ -139,6 +139,7 @@ int blockstore::dequeue_write(blockstore_operation *op)
         je->offset = op->offset;
         je->len = op->len;
         je->data_offset = journal.next_free;
+        je->crc32_data = crc32c(0, op->buf, op->len);
         je->crc32 = je_crc32((journal_entry*)je);
         journal.crc32_last = je->crc32;
         prepare_journal_sector_write(journal, sqe1, cb);