From dea29460ed513f965de2dcac9e29180b06d56b58 Mon Sep 17 00:00:00 2001
From: "Adam C. Emerson" <aemerson@redhat.com>
Date: Fri, 17 Nov 2017 15:51:42 -0500
Subject: [PATCH] rgw: Add retry_raced_bucket_write

If the OSD informs us that our bucket info is out of date when we need
to write, we should have a way to update it.

This template function allows us to wrap relevant sections of code so
they'll be retried against new bucket info on -ECANCELED.

Signed-off-by: Adam C. Emerson <aemerson@redhat.com>
(cherry picked from commit 1a3fcc70c0747791aa423cd0aa7d2596eaf3d73c)
Fixes: http://tracker.ceph.com/issues/22517
---
 src/rgw/rgw_op.cc | 31 +++++++++++++++++++++++++++++++
 src/rgw/rgw_op.h  |  1 +
 2 files changed, 32 insertions(+)

diff --git a/src/rgw/rgw_op.cc b/src/rgw/rgw_op.cc
index 11fdbd4ebc3fd..15bd3baa877ba 100644
--- a/src/rgw/rgw_op.cc
+++ b/src/rgw/rgw_op.cc
@@ -647,6 +647,37 @@ void rgw_bucket_object_pre_exec(struct req_state *s)
   dump_bucket_from_state(s);
 }
 
+// So! Now and then when we try to update bucket information, the
+// bucket has changed during the course of the operation. (Or we have
+// a cache consistency problem that Watch/Notify isn't ruling out
+// completely.)
+//
+// When this happens, we need to update the bucket info and try
+// again. We have, however, to try the right *part* again.  We can't
+// simply re-send, since that will obliterate the previous update.
+//
+// Thus, callers of this function should include everything that
+// merges information to be changed into the bucket information as
+// well as the call to set it.
+//
+// The called function must return an integer, negative on error. In
+// general, they should just return op_ret.
+namespace {
+template<typename F>
+int retry_raced_bucket_write(RGWRados* g, req_state* s, const F& f) {
+  auto r = f();
+  for (auto i = 0u; i < 15u && r == -ECANCELED; ++i) {
+    r = g->try_refresh_bucket_info(s->bucket_info, nullptr,
+				   &s->bucket_attrs);
+    if (r >= 0) {
+      r = f();
+    }
+  }
+  return r;
+}
+}
+
+
 int RGWGetObj::verify_permission()
 {
   obj = rgw_obj(s->bucket, s->object);
diff --git a/src/rgw/rgw_op.h b/src/rgw/rgw_op.h
index 68b83a45f1338..1db3521ab00c4 100644
--- a/src/rgw/rgw_op.h
+++ b/src/rgw/rgw_op.h
@@ -120,6 +120,7 @@ protected:
   int do_aws4_auth_completion();
 
   virtual int init_quota();
+
 public:
   RGWOp()
     : s(nullptr),
-- 
2.39.5