From: Sage Weil <sage@newdream.net>
Date: Thu, 13 Nov 2008 21:30:26 +0000 (-0800)
Subject: mds: treat open requests as non-idempotent
X-Git-Tag: v0.5~5^2~7
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=93914659103fb4c6eb76a0760dcb10db36e556f5;p=ceph.git

mds: treat open requests as non-idempotent

The problem is that the reply contains a capability, and as such
is statefull and can't be lost.  Forwards by the MDS on behalf of
the client, however, introduce the possibility of multiple copies
or a request in flight if one of the MDSs fails, and the client
will drop any duplicate replies it receives.

Alternatively, the client could _also_ parse duplicate responses
(i.e. call fill_trace).  I'm not sure if that's a good idea.  In
any case, MDS forwarded requests are only really important for
dealing with flash flood scenarios on extremely large clusters,
so let's just set this aside for now.
---

diff --git a/src/messages/MClientRequest.h b/src/messages/MClientRequest.h
index a5a2f9c79f774..6d76de6993eeb 100644
--- a/src/messages/MClientRequest.h
+++ b/src/messages/MClientRequest.h
@@ -79,7 +79,7 @@ public:
   }
   bool is_idempotent() {
     if (head.op == CEPH_MDS_OP_OPEN) 
-      return open_file_mode_is_readonly();
+      return false;  //open_file_mode_is_readonly();
     return (head.op & CEPH_MDS_OP_WRITE) == 0;
   }
   bool auth_is_best() {