From fae947d43333be0c151ebe5c8ef9c0264f08fb03 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 16 Dec 2018 18:00:54 -0800
Subject: [PATCH] ircd::db: Add a background cancel interface w/ console cmd.

---
 include/ircd/db/database/database.h |  1 +
 ircd/db.cc                          | 41 +++++++++++++++++++++++++++++
 modules/console.cc                  | 29 ++++++++++++++++++++
 3 files changed, 71 insertions(+)

diff --git a/include/ircd/db/database/database.h b/include/ircd/db/database/database.h
index 7cad780c9..4592a64b7 100644
--- a/include/ircd/db/database/database.h
+++ b/include/ircd/db/database/database.h
@@ -48,6 +48,7 @@ namespace ircd::db
 	void setopt(database &, const string_view &key, const string_view &val);
 	void fdeletions(database &, const bool &enable, const bool &force = false);
 	uint64_t checkpoint(database &);
+	void bgcancel(database &, const bool &blocking = true);
 	void bgcontinue(database &);
 	void bgpause(database &);
 	void resume(database &);
diff --git a/ircd/db.cc b/ircd/db.cc
index d2f45ee5d..325f52abb 100644
--- a/ircd/db.cc
+++ b/ircd/db.cc
@@ -525,6 +525,47 @@ ircd::db::bgcontinue(database &d)
 	};
 }
 
+void
+ircd::db::bgcancel(database &d,
+                   const bool &blocking)
+{
+	assert(d.d);
+	log::debug
+	{
+		log, "'%s': Canceling all background work...",
+		name(d)
+	};
+
+	rocksdb::CancelAllBackgroundWork(d.d.get(), blocking);
+	if(!blocking)
+		return;
+
+	assert(d.env);
+	assert(d.env->st);
+	const ctx::uninterruptible::nothrow ui;
+	for(auto &pool : d.env->st->pool)
+		if(pool)
+			pool->wait();
+
+	const auto errors
+	{
+		property<uint64_t>(d, rocksdb::DB::Properties::kBackgroundErrors)
+	};
+
+	const auto facility
+	{
+		errors? log::facility::ERROR : log::facility::DEBUG
+	};
+
+	log::logf
+	{
+		log, facility,
+		"'%s': Canceled all background work; errors:%lu",
+		name(d),
+		errors
+	};
+}
+
 /// Writes a snapshot of this database to the directory specified. The
 /// snapshot consists of hardlinks to the bulk data files of this db, but
 /// copies the other stuff that usually gets corrupted. The directory can
diff --git a/modules/console.cc b/modules/console.cc
index 209b3b242..3fd266dfa 100644
--- a/modules/console.cc
+++ b/modules/console.cc
@@ -1441,6 +1441,35 @@ catch(const std::out_of_range &e)
 	return true;
 }
 
+bool
+console_cmd__db__cancel(opt &out, const string_view &line)
+try
+{
+	const params param{line, " ",
+	{
+		"dbname",
+	}};
+
+	const auto dbname
+	{
+		param.at(0)
+	};
+
+	auto &database
+	{
+		db::database::get(dbname)
+	};
+
+	bgcancel(database);
+	out << "canceld background jobs for '" << dbname << "'" << std::endl;
+	return true;
+}
+catch(const std::out_of_range &e)
+{
+	out << "No open database by that name" << std::endl;
+	return true;
+}
+
 bool
 console_cmd__db__sync(opt &out, const string_view &line)
 try