nbd: Detect servers that send unexpected error values

Add some debugging to flag servers that are not compliant to
the NBD protocol.  This would have flagged the server bug
fixed in commit c0301fcc.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Message-Id: <1463006384-7734-11-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/nbd/client.c b/nbd/client.c
index 20e6daf..e8bf9fb 100644 (file)
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -33,8 +33,10 @@ static int nbd_errno_to_system_errno(int err)
         return ENOMEM;
     case NBD_ENOSPC:
         return ENOSPC;
-    case NBD_EINVAL:
     default:
+        TRACE("Squashing unexpected error %d to EINVAL", err);
+        /* fallthrough */
+    case NBD_EINVAL:
         return EINVAL;
     }
 }