From 986776d30d18719e18478da3627680ee7ce57b29 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Wed, 8 Mar 2017 15:01:28 -0500
Subject: [PATCH] os/bluestore: reimplement/rename _sync -> _flush_all

The old implementation is racy and doesn't actually work.  Instead, rely
on a list of all OpSequencers and drain them all.

Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/os/bluestore/BlueStore.cc | 39 +++++++++++++++++++----------------
 src/os/bluestore/BlueStore.h  |  2 +-
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/src/os/bluestore/BlueStore.cc b/src/os/bluestore/BlueStore.cc
index d726469ad64..04ca35354cc 100644
--- a/src/os/bluestore/BlueStore.cc
+++ b/src/os/bluestore/BlueStore.cc
@@ -4814,7 +4814,7 @@ int BlueStore::umount()
   assert(mounted);
   dout(1) << __func__ << dendl;
 
-  _sync();
+  _osr_drain_all();
 
   mempool_thread.shutdown();
 
@@ -5408,23 +5408,6 @@ int BlueStore::fsck(bool deep)
   return errors;
 }
 
-void BlueStore::_sync()
-{
-  dout(10) << __func__ << dendl;
-
-  // flush aios in flight
-  bdev->flush();
-
-  std::unique_lock<std::mutex> l(kv_lock);
-  while (!kv_committing.empty() ||
-	 !kv_queue.empty()) {
-    dout(20) << " waiting for kv to commit" << dendl;
-    kv_sync_cond.wait(l);
-  }
-
-  dout(10) << __func__ << " done" << dendl;
-}
-
 int BlueStore::statfs(struct store_statfs_t *buf)
 {
   buf->reset();
@@ -7512,6 +7495,26 @@ void BlueStore::_txc_release_alloc(TransContext *txc)
   txc->released.clear();
 }
 
+void BlueStore::_osr_drain_all()
+{
+  dout(10) << __func__ << dendl;
+
+  // WARNING: we make a (somewhat sloppy) assumption here that
+  // no OpSequencers will be created or destroyed for the duration
+  // of this method.
+  set<OpSequencer*> s;
+  {
+    std::lock_guard<std::mutex> l(osr_lock);
+    s = osr_set;
+  }
+  for (auto osr : s) {
+    dout(20) << __func__ << " flush " << osr << dendl;
+    osr->drain();
+  }
+
+  dout(10) << __func__ << " done" << dendl;
+}
+
 void BlueStore::_kv_sync_thread()
 {
   dout(10) << __func__ << " start" << dendl;
diff --git a/src/os/bluestore/BlueStore.h b/src/os/bluestore/BlueStore.h
index d419e4b14d6..6bd3b20c25b 100644
--- a/src/os/bluestore/BlueStore.h
+++ b/src/os/bluestore/BlueStore.h
@@ -1889,6 +1889,7 @@ private:
   void _txc_release_alloc(TransContext *txc);
 
   void _osr_reap_done(OpSequencer *osr);
+  void _osr_drain_all();
 
   void _kv_sync_thread();
   void _kv_stop() {
@@ -1974,7 +1975,6 @@ public:
 
   int mount() override;
   int umount() override;
-  void _sync();
 
   int fsck(bool deep) override;
 
-- 
2.39.5