From 4c20310db81ee3aca81ada23ce3c671e72c6f2ae Mon Sep 17 00:00:00 2001
From: ningtao <63358@sangfor.com>
Date: Thu, 12 Jul 2018 17:44:33 +0800
Subject: [PATCH] librbd:optionally support FUA (force unit access) on write
 requests

Fixes: http://tracker.ceph.com/issues/19366

Signed-off-by: ningtao <63358@sangfor.com>
---
 src/include/rados/librados.h   |  2 ++
 src/osdc/ObjectCacher.cc       |  2 +-
 src/test/librbd/test_librbd.cc | 49 ++++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/src/include/rados/librados.h b/src/include/rados/librados.h
index 03ad017464dca..e7cacbb2402aa 100644
--- a/src/include/rados/librados.h
+++ b/src/include/rados/librados.h
@@ -81,6 +81,8 @@ enum {
   LIBRADOS_OP_FLAG_FADVISE_DONTNEED   = 0x20,
   // indicate read/write data will not accessed again (by *this* client)
   LIBRADOS_OP_FLAG_FADVISE_NOCACHE    = 0x40,
+  // optionally support FUA (force unit access) on write requests
+  LIBRADOS_OP_FLAG_FADVISE_FUA        = 0x80,
 };
 
 #if __GNUC__ >= 4
diff --git a/src/osdc/ObjectCacher.cc b/src/osdc/ObjectCacher.cc
index b577edd95b9b5..e99b1e13e4eef 100644
--- a/src/osdc/ObjectCacher.cc
+++ b/src/osdc/ObjectCacher.cc
@@ -1849,7 +1849,7 @@ int ObjectCacher::_wait_for_write(OSDWrite *wr, uint64_t len, ObjectSet *oset,
   assert(trace != nullptr);
   int ret = 0;
 
-  if (max_dirty > 0) {
+  if (max_dirty > 0 && !(wr->fadvise_flags & LIBRADOS_OP_FLAG_FADVISE_FUA)) {
     if (block_writes_upfront) {
       maybe_wait_for_writeback(len, trace);
       if (onfreespace)
diff --git a/src/test/librbd/test_librbd.cc b/src/test/librbd/test_librbd.cc
index df671728eaf3a..4d2448cade987 100644
--- a/src/test/librbd/test_librbd.cc
+++ b/src/test/librbd/test_librbd.cc
@@ -2345,6 +2345,55 @@ TEST_F(TestLibRBD, TestEmptyDiscard)
   rados_ioctx_destroy(ioctx);
 }
 
+TEST_F(TestLibRBD, TestFUA)
+{
+  rados_ioctx_t ioctx;
+  rados_ioctx_create(_cluster, m_pool_name.c_str(), &ioctx);
+
+  rbd_image_t image_write;
+  rbd_image_t image_read;
+  int order = 0;
+  std::string name = get_temp_image_name();
+  uint64_t size = 2 << 20;
+  size_t num_aios = 256;
+
+  ASSERT_EQ(0, create_image(ioctx, name.c_str(), size, &order));
+  ASSERT_EQ(0, rbd_open(ioctx, name.c_str(), &image_write, NULL));
+  ASSERT_EQ(0, rbd_open(ioctx, name.c_str(), &image_read, NULL));
+
+  // enable writeback cache
+  rbd_flush(image_write);
+
+  char test_data[TEST_IO_SIZE + 1];
+  int i;
+
+  for (i = 0; i < TEST_IO_SIZE; ++i) {
+    test_data[i] = (char) (rand() % (126 - 33) + 33);
+  }
+  test_data[TEST_IO_SIZE] = '\0';
+  for (i = 0; i < 5; ++i)
+    ASSERT_PASSED(write_test_data, image_write, test_data,
+                  TEST_IO_SIZE * i, TEST_IO_SIZE, LIBRADOS_OP_FLAG_FADVISE_FUA);
+
+  for (i = 0; i < 5; ++i)
+    ASSERT_PASSED(read_test_data, image_read, test_data,
+                  TEST_IO_SIZE * i, TEST_IO_SIZE, 0);
+
+  for (i = 5; i < 10; ++i)
+    ASSERT_PASSED(aio_write_test_data, image_write, test_data,
+                  TEST_IO_SIZE * i, TEST_IO_SIZE, LIBRADOS_OP_FLAG_FADVISE_FUA);
+
+  for (i = 5; i < 10; ++i)
+    ASSERT_PASSED(aio_read_test_data, image_read, test_data,
+                  TEST_IO_SIZE * i, TEST_IO_SIZE, 0);
+
+  ASSERT_PASSED(validate_object_map, image_write);
+  ASSERT_PASSED(validate_object_map, image_read);
+  ASSERT_EQ(0, rbd_close(image_write));
+  ASSERT_EQ(0, rbd_close(image_read));
+  ASSERT_EQ(0, rbd_remove(ioctx, name.c_str()));
+  rados_ioctx_destroy(ioctx);
+}
 
 void simple_write_cb_pp(librbd::completion_t cb, void *arg)
 {
-- 
2.39.5