From 363ebb6cccbe21711b0e0c570b75739791b80195 Mon Sep 17 00:00:00 2001
From: Josh Durgin <josh.durgin@dreamhost.com>
Date: Tue, 15 Nov 2011 14:27:53 -0800
Subject: [PATCH] librbd: report an error if rbd header does not match

This will fail on future incompatible versions of the header format.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
---
 src/librbd.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/librbd.cc b/src/librbd.cc
index ed6734f03b2e1..ced1b0c330b72 100644
--- a/src/librbd.cc
+++ b/src/librbd.cc
@@ -585,6 +585,12 @@ int read_header_bl(IoCtx& io_ctx, const string& md_oid, bufferlist& header, uint
     header.claim_append(bl);
    } while (r == READ_SIZE);
 
+  if (memcmp(RBD_HEADER_TEXT, header.c_str(), sizeof(RBD_HEADER_TEXT))) {
+    CephContext *cct = io_ctx.cct();
+    lderr(cct) << "unrecognized header format" << dendl;
+    return -ENXIO;
+  }
+
   if (ver)
     *ver = io_ctx.get_last_version();
 
-- 
2.39.5