osdc: Interface to allow split reads to copy op from client op to split op

When spliting ops, certain addition sub ops (e.g. get xattr) can be simply passed
through to the child op.

Signed-off-by: Alex Ainscow <[email protected]>

Author: aainscow

src/osdc/Objecter.h

@@ -161,6 +161,11 @@ struct ObjectOperation {
 
   }
 
+  OSDOp& pass_thru_op(OSDOp& op) {
+    ops.emplace_back(op);
+    return ops.back();
+  }
+
   OSDOp& add_op(int op) {
     ops.emplace_back();
     ops.back().op.op = op;
@@ -2120,6 +2125,26 @@ class Objecter : public md_config_obs_t, public Dispatcher {
       return tid < other.tid;
     }
 
+    void pass_thru_op(::ObjectOperation &other, unsigned index, bufferlist *bl, int *rval) {
+      ceph_assert(index < ops.size());
+
+      other.pass_thru_op(ops[index]);
+      unsigned p = other.ops.size() - 1;
+      ceph_assert(out_bl.size() == ops.size());
+      ceph_assert(out_rval.size() == ops.size());
+      ceph_assert(out_ec.size() == ops.size());
+      ceph_assert(out_handler.size() == ops.size());
+
+      other.out_bl.resize(p + 1);
+      other.out_rval.resize(p + 1);
+      other.out_ec.resize(p + 1);
+      other.out_handler.resize(p + 1);
+
+      other.out_bl[p] = bl;
+      other.out_rval[p] = rval;
+      // We don't copy the out handler here - it must be run by the copied-from op.
+    }
+
   private:
     ~Op() override {
       trace.event("finish");