osd/PrimaryLogPG: record prior_version for DELETE events

Leaving this blank is inaccurate.  It also confuses the rewind
divergent log code, leading to behavior like

      ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
			 << " prior_version or op type indicates creation,"
			 << " deleting"
			 << dendl;

Fixes: http://tracker.ceph.com/issues/20274
Signed-off-by: Sage Weil <sage@redhat.com>

src/osd/PrimaryLogPG.cc

@@ -2253,7 +2253,9 @@ void PrimaryLogPG::do_op(OpRequestRef& op)
     close_op_ctx(ctx);
     if (op->may_write() &&
 	get_osdmap()->require_osd_release >= CEPH_RELEASE_KRAKEN) {
-      record_write_error(op, oid, nullptr, r);
+      record_write_error(op, oid,
+			 obc ? obc->obs.oi.version : eversion_t(),
+			 nullptr, r);
     } else {
       osd->reply_op_error(op, r);
     }
@@ -2352,6 +2354,7 @@ PrimaryLogPG::cache_result_t PrimaryLogPG::maybe_handle_manifest_detail(
 }
 
 void PrimaryLogPG::record_write_error(OpRequestRef op, const hobject_t &soid,
+				      eversion_t prior_version,
 				      MOSDOpReply *orig_reply, int r)
 {
   dout(20) << __func__ << " r=" << r << dendl;
@@ -2360,7 +2363,7 @@ void PrimaryLogPG::record_write_error(OpRequestRef op, const hobject_t &soid,
   ObjectContextRef obc;
   mempool::osd_pglog::list<pg_log_entry_t> entries;
   entries.push_back(pg_log_entry_t(pg_log_entry_t::ERROR, soid,
-				   get_next_version(), eversion_t(), 0,
+				   get_next_version(), prior_version, 0,
 				   reqid, utime_t(), r));
 
   struct OnComplete {
@@ -3293,7 +3296,10 @@ void PrimaryLogPG::execute_ctx(OpContext *ctx)
     }
     reply->add_flags(CEPH_OSD_FLAG_ACK | CEPH_OSD_FLAG_ONDISK);
     // append to pg log for dup detection - don't save buffers for now
-    record_write_error(op, soid, reply, result);
+    record_write_error(
+      op, soid,
+      obc->obs.oi.version,
+      reply, result);
     return;
   }
 

src/osd/PrimaryLogPG.h

@@ -1374,6 +1374,7 @@ class PrimaryLogPG : public PG, public PGBackend::Listener {
     ThreadPool::TPHandle &handle) override;
   void do_op(OpRequestRef& op) override;
   void record_write_error(OpRequestRef op, const hobject_t &soid,
+			  eversion_t prior_version,
 			  MOSDOpReply *orig_reply, int r);
   void do_pg_op(OpRequestRef op);
   void do_sub_op(OpRequestRef op) override;