From b0b4ba269808cb151c037b920b6c2ffe6c7725dd Mon Sep 17 00:00:00 2001
From: Jason Dillaman <dillaman@redhat.com>
Date: Thu, 17 Sep 2020 09:51:49 -0400
Subject: [PATCH] librbd: assign a unique flush source to each internal
 component

This will allow improved tracking and bypassing of a flush request
that might cause IO deadlocks in dispatch layers.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---
 src/librbd/exclusive_lock/ImageDispatch.cc | 2 +-
 src/librbd/image/CloseRequest.cc           | 2 +-
 src/librbd/image/RefreshRequest.cc         | 4 ++--
 src/librbd/io/Types.h                      | 6 +++++-
 src/librbd/io/WriteBlockImageDispatch.cc   | 2 +-
 5 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/librbd/exclusive_lock/ImageDispatch.cc b/src/librbd/exclusive_lock/ImageDispatch.cc
index 87007c60a73fe..fe3ab14bace24 100644
--- a/src/librbd/exclusive_lock/ImageDispatch.cc
+++ b/src/librbd/exclusive_lock/ImageDispatch.cc
@@ -72,7 +72,7 @@ void ImageDispatch<I>::set_require_lock(io::Direction direction,
     on_finish, util::get_image_ctx(m_image_ctx), io::AIO_TYPE_FLUSH);
   auto req = io::ImageDispatchSpec::create_flush(
     *m_image_ctx, io::IMAGE_DISPATCH_LAYER_EXCLUSIVE_LOCK, aio_comp,
-    io::FLUSH_SOURCE_INTERNAL, {});
+    io::FLUSH_SOURCE_EXCLUSIVE_LOCK, {});
   req->send();
 }
 
diff --git a/src/librbd/image/CloseRequest.cc b/src/librbd/image/CloseRequest.cc
index 04f8b6f630b5f..7293687f5b81c 100644
--- a/src/librbd/image/CloseRequest.cc
+++ b/src/librbd/image/CloseRequest.cc
@@ -105,7 +105,7 @@ void CloseRequest<I>::send_flush() {
                                                       io::AIO_TYPE_FLUSH);
   auto req = io::ImageDispatchSpec::create_flush(
     *m_image_ctx, io::IMAGE_DISPATCH_LAYER_API_START, aio_comp,
-    io::FLUSH_SOURCE_INTERNAL, {});
+    io::FLUSH_SOURCE_SHUTDOWN, {});
   req->send();
 }
 
diff --git a/src/librbd/image/RefreshRequest.cc b/src/librbd/image/RefreshRequest.cc
index 735d701b61a1c..b66f375315f14 100644
--- a/src/librbd/image/RefreshRequest.cc
+++ b/src/librbd/image/RefreshRequest.cc
@@ -1246,8 +1246,8 @@ Context *RefreshRequest<I>::send_flush_aio() {
     auto aio_comp = io::AioCompletion::create_and_start(
       ctx, util::get_image_ctx(&m_image_ctx), io::AIO_TYPE_FLUSH);
     auto req = io::ImageDispatchSpec::create_flush(
-      m_image_ctx, io::IMAGE_DISPATCH_LAYER_INTERNAL_START, aio_comp,
-      io::FLUSH_SOURCE_INTERNAL, {});
+      m_image_ctx, io::IMAGE_DISPATCH_LAYER_REFRESH, aio_comp,
+      io::FLUSH_SOURCE_REFRESH, {});
     req->send();
     return nullptr;
   } else if (m_error_result < 0) {
diff --git a/src/librbd/io/Types.h b/src/librbd/io/Types.h
index 66a7635cd5321..6193e2f5a0987 100644
--- a/src/librbd/io/Types.h
+++ b/src/librbd/io/Types.h
@@ -31,7 +31,11 @@ enum FlushSource {
   FLUSH_SOURCE_USER,
   FLUSH_SOURCE_INTERNAL,
   FLUSH_SOURCE_SHUTDOWN,
-  FLUSH_SOURCE_WRITEBACK
+  FLUSH_SOURCE_EXCLUSIVE_LOCK,
+  FLUSH_SOURCE_EXCLUSIVE_LOCK_SKIP_REFRESH,
+  FLUSH_SOURCE_REFRESH,
+  FLUSH_SOURCE_WRITEBACK,
+  FLUSH_SOURCE_WRITE_BLOCK,
 };
 
 enum Direction {
diff --git a/src/librbd/io/WriteBlockImageDispatch.cc b/src/librbd/io/WriteBlockImageDispatch.cc
index e489524995da3..729ecc5e60041 100644
--- a/src/librbd/io/WriteBlockImageDispatch.cc
+++ b/src/librbd/io/WriteBlockImageDispatch.cc
@@ -254,7 +254,7 @@ void WriteBlockImageDispatch<I>::flush_io(Context* on_finish) {
     on_finish, util::get_image_ctx(m_image_ctx), librbd::io::AIO_TYPE_FLUSH);
   auto req = ImageDispatchSpec::create_flush(
     *m_image_ctx, IMAGE_DISPATCH_LAYER_WRITE_BLOCK, aio_comp,
-    FLUSH_SOURCE_INTERNAL, {});
+    FLUSH_SOURCE_WRITE_BLOCK, {});
   req->send();
 }
 
-- 
2.39.5