From: Sage Weil <sage@inktank.com>
Date: Tue, 24 Sep 2013 19:48:07 +0000 (-0700)
Subject: librados: add OPERATION_ORDER_READS_WRITES flag
X-Git-Tag: v0.71~75^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=3faf08f5f96ced6eecb3c2bc3a6b7bf4fc5a1b73;p=ceph.git

librados: add OPERATION_ORDER_READS_WRITES flag

This maps to the internal RWORDERED option, which indicates that a read
should be ordered the same way a write is.

Signed-off-by: Sage Weil <sage@inktank.com>
---

diff --git a/src/include/rados/librados.hpp b/src/include/rados/librados.hpp
index 94d3d23a8244..358142c8cb4c 100644
--- a/src/include/rados/librados.hpp
+++ b/src/include/rados/librados.hpp
@@ -133,11 +133,16 @@ namespace librados
    * BALANCE_READS and LOCALIZE_READS should only be used
    * when reading from data you're certain won't change,
    * like a snapshot, or where eventual consistency is ok.
+   *
+   * ORDER_READS_WRITES will order reads the same way writes are
+   * ordered (e.g., waiting for degraded objects).  In particular, it
+   * will make a write followed by a read sequence be preserved.
    */
   enum ObjectOperationGlobalFlags {
     OPERATION_NOFLAG         = 0,
     OPERATION_BALANCE_READS  = 1,
     OPERATION_LOCALIZE_READS = 2,
+    OPERATION_ORDER_READS_WRITES = 4,
   };
 
   /*
diff --git a/src/librados/librados.cc b/src/librados/librados.cc
index 852228ed3834..63092d1093d9 100644
--- a/src/librados/librados.cc
+++ b/src/librados/librados.cc
@@ -958,6 +958,8 @@ int librados::IoCtx::aio_operate(const std::string& oid, AioCompletion *c,
     op_flags |= CEPH_OSD_FLAG_BALANCE_READS;
   if (flags & OPERATION_LOCALIZE_READS)
     op_flags |= CEPH_OSD_FLAG_LOCALIZE_READS;
+  if (flags & OPERATION_ORDER_READS_WRITES)
+    op_flags |= CEPH_OSD_FLAG_RWORDERED;
 
   return io_ctx_impl->aio_operate_read(obj, (::ObjectOperation*)o->impl, c->pc,
 				       op_flags, pbl);