diff --git a/base/Android.bp b/base/Android.bp
index aeb8864..8351461 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -149,6 +149,7 @@
         "logging_test.cpp",
         "macros_test.cpp",
         "mapped_file_test.cpp",
+        "no_destructor_test.cpp",
         "parsedouble_test.cpp",
         "parsebool_test.cpp",
         "parseint_test.cpp",
diff --git a/base/include/android-base/no_destructor.h b/base/include/android-base/no_destructor.h
new file mode 100644
index 0000000..ce0dc9f
--- /dev/null
+++ b/base/include/android-base/no_destructor.h
@@ -0,0 +1,94 @@
+#pragma once
+
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <utility>
+
+#include "android-base/macros.h"
+
+namespace android {
+namespace base {
+
+// A wrapper that makes it easy to create an object of type T with static
+// storage duration that:
+// - is only constructed on first access
+// - never invokes the destructor
+// in order to satisfy the styleguide ban on global constructors and
+// destructors.
+//
+// Runtime constant example:
+// const std::string& GetLineSeparator() {
+//  // Forwards to std::string(size_t, char, const Allocator&) constructor.
+//   static const base::NoDestructor<std::string> s(5, '-');
+//   return *s;
+// }
+//
+// More complex initialization with a lambda:
+// const std::string& GetSessionNonce() {
+//   static const base::NoDestructor<std::string> nonce([] {
+//     std::string s(16);
+//     crypto::RandString(s.data(), s.size());
+//     return s;
+//   }());
+//   return *nonce;
+// }
+//
+// NoDestructor<T> stores the object inline, so it also avoids a pointer
+// indirection and a malloc. Also note that since C++11 static local variable
+// initialization is thread-safe and so is this pattern. Code should prefer to
+// use NoDestructor<T> over:
+// - A function scoped static T* or T& that is dynamically initialized.
+// - A global base::LazyInstance<T>.
+//
+// Note that since the destructor is never run, this *will* leak memory if used
+// as a stack or member variable. Furthermore, a NoDestructor<T> should never
+// have global scope as that may require a static initializer.
+template <typename T>
+class NoDestructor {
+ public:
+  // Not constexpr; just write static constexpr T x = ...; if the value should
+  // be a constexpr.
+  template <typename... Args>
+  explicit NoDestructor(Args&&... args) {
+    new (storage_) T(std::forward<Args>(args)...);
+  }
+
+  // Allows copy and move construction of the contained type, to allow
+  // construction from an initializer list, e.g. for std::vector.
+  explicit NoDestructor(const T& x) { new (storage_) T(x); }
+  explicit NoDestructor(T&& x) { new (storage_) T(std::move(x)); }
+
+  NoDestructor(const NoDestructor&) = delete;
+  NoDestructor& operator=(const NoDestructor&) = delete;
+
+  ~NoDestructor() = default;
+
+  const T& operator*() const { return *get(); }
+  T& operator*() { return *get(); }
+
+  const T* operator->() const { return get(); }
+  T* operator->() { return get(); }
+
+  const T* get() const { return reinterpret_cast<const T*>(storage_); }
+  T* get() { return reinterpret_cast<T*>(storage_); }
+
+ private:
+  alignas(T) char storage_[sizeof(T)];
+};
+
+}  // namespace base
+}  // namespace android
diff --git a/base/no_destructor_test.cpp b/base/no_destructor_test.cpp
new file mode 100644
index 0000000..f19468a
--- /dev/null
+++ b/base/no_destructor_test.cpp
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "android-base/no_destructor.h"
+
+#include <gtest/gtest.h>
+
+struct __attribute__((packed)) Bomb {
+  Bomb() : magic_(123) {}
+
+  ~Bomb() { exit(42); }
+
+  int get() const { return magic_; }
+
+ private:
+  [[maybe_unused]] char padding_;
+  int magic_;
+};
+
+TEST(no_destructor, bomb) {
+  ASSERT_EXIT(({
+                {
+                  Bomb b;
+                  if (b.get() != 123) exit(1);
+                }
+
+                exit(0);
+              }),
+              ::testing::ExitedWithCode(42), "");
+}
+
+TEST(no_destructor, defused) {
+  ASSERT_EXIT(({
+                {
+                  android::base::NoDestructor<Bomb> b;
+                  if (b->get() != 123) exit(1);
+                }
+
+                exit(0);
+              }),
+              ::testing::ExitedWithCode(0), "");
+}
+
+TEST(no_destructor, operators) {
+  android::base::NoDestructor<Bomb> b;
+  const android::base::NoDestructor<Bomb>& c = b;
+  ASSERT_EQ(123, b.get()->get());
+  ASSERT_EQ(123, b->get());
+  ASSERT_EQ(123, (*b).get());
+  ASSERT_EQ(123, c.get()->get());
+  ASSERT_EQ(123, c->get());
+  ASSERT_EQ(123, (*c).get());
+}
diff --git a/fs_mgr/libdm/dm.cpp b/fs_mgr/libdm/dm.cpp
index 824ee43..809318c 100644
--- a/fs_mgr/libdm/dm.cpp
+++ b/fs_mgr/libdm/dm.cpp
@@ -16,12 +16,14 @@
 
 #include "libdm/dm.h"
 
+#include <linux/dm-ioctl.h>
 #include <sys/ioctl.h>
 #include <sys/sysmacros.h>
 #include <sys/types.h>
 
 #include <chrono>
 #include <functional>
+#include <string_view>
 #include <thread>
 
 #include <android-base/file.h>
@@ -504,5 +506,74 @@
     return std::string{spec.target_type, sizeof(spec.target_type)};
 }
 
+static bool ExtractBlockDeviceName(const std::string& path, std::string* name) {
+    static constexpr std::string_view kDevBlockPrefix("/dev/block/");
+    if (android::base::StartsWith(path, kDevBlockPrefix)) {
+        *name = path.substr(kDevBlockPrefix.length());
+        return true;
+    }
+    return false;
+}
+
+bool DeviceMapper::IsDmBlockDevice(const std::string& path) {
+    std::string name;
+    if (!ExtractBlockDeviceName(path, &name)) {
+        return false;
+    }
+    return android::base::StartsWith(name, "dm-");
+}
+
+std::optional<std::string> DeviceMapper::GetDmDeviceNameByPath(const std::string& path) {
+    std::string name;
+    if (!ExtractBlockDeviceName(path, &name)) {
+        LOG(WARNING) << path << " is not a block device";
+        return std::nullopt;
+    }
+    if (!android::base::StartsWith(name, "dm-")) {
+        LOG(WARNING) << path << " is not a dm device";
+        return std::nullopt;
+    }
+    std::string dm_name_file = "/sys/block/" + name + "/dm/name";
+    std::string dm_name;
+    if (!android::base::ReadFileToString(dm_name_file, &dm_name)) {
+        PLOG(ERROR) << "Failed to read file " << dm_name_file;
+        return std::nullopt;
+    }
+    dm_name = android::base::Trim(dm_name);
+    return dm_name;
+}
+
+std::optional<std::string> DeviceMapper::GetParentBlockDeviceByPath(const std::string& path) {
+    std::string name;
+    if (!ExtractBlockDeviceName(path, &name)) {
+        LOG(WARNING) << path << " is not a block device";
+        return std::nullopt;
+    }
+    if (!android::base::StartsWith(name, "dm-")) {
+        // Reached bottom of the device mapper stack.
+        return std::nullopt;
+    }
+    auto slaves_dir = "/sys/block/" + name + "/slaves";
+    auto dir = std::unique_ptr<DIR, decltype(&closedir)>(opendir(slaves_dir.c_str()), closedir);
+    if (dir == nullptr) {
+        PLOG(ERROR) << "Failed to open: " << slaves_dir;
+        return std::nullopt;
+    }
+    std::string sub_device_name = "";
+    for (auto entry = readdir(dir.get()); entry; entry = readdir(dir.get())) {
+        if (entry->d_type != DT_LNK) continue;
+        if (!sub_device_name.empty()) {
+            LOG(ERROR) << "Too many slaves in " << slaves_dir;
+            return std::nullopt;
+        }
+        sub_device_name = entry->d_name;
+    }
+    if (sub_device_name.empty()) {
+        LOG(ERROR) << "No slaves in " << slaves_dir;
+        return std::nullopt;
+    }
+    return "/dev/block/" + sub_device_name;
+}
+
 }  // namespace dm
 }  // namespace android
diff --git a/fs_mgr/libdm/dm_test.cpp b/fs_mgr/libdm/dm_test.cpp
index 1695953..b7f31bc 100644
--- a/fs_mgr/libdm/dm_test.cpp
+++ b/fs_mgr/libdm/dm_test.cpp
@@ -29,6 +29,7 @@
 #include <thread>
 
 #include <android-base/file.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
 #include <libdm/dm.h>
@@ -544,3 +545,63 @@
     ASSERT_NE(0, access(path.c_str(), F_OK));
     ASSERT_EQ(ENOENT, errno);
 }
+
+TEST(libdm, IsDmBlockDevice) {
+    unique_fd tmp(CreateTempFile("file_1", 4096));
+    ASSERT_GE(tmp, 0);
+    LoopDevice loop(tmp, 10s);
+    ASSERT_TRUE(loop.valid());
+    ASSERT_TRUE(android::base::StartsWith(loop.device(), "/dev/block"));
+
+    DmTable table;
+    ASSERT_TRUE(table.Emplace<DmTargetLinear>(0, 1, loop.device(), 0));
+    ASSERT_TRUE(table.valid());
+
+    TempDevice dev("libdm-test-dm-linear", table);
+    ASSERT_TRUE(dev.valid());
+
+    DeviceMapper& dm = DeviceMapper::Instance();
+    ASSERT_TRUE(dm.IsDmBlockDevice(dev.path()));
+    ASSERT_FALSE(dm.IsDmBlockDevice(loop.device()));
+}
+
+TEST(libdm, GetDmDeviceNameByPath) {
+    unique_fd tmp(CreateTempFile("file_1", 4096));
+    ASSERT_GE(tmp, 0);
+    LoopDevice loop(tmp, 10s);
+    ASSERT_TRUE(loop.valid());
+    ASSERT_TRUE(android::base::StartsWith(loop.device(), "/dev/block"));
+
+    DmTable table;
+    ASSERT_TRUE(table.Emplace<DmTargetLinear>(0, 1, loop.device(), 0));
+    ASSERT_TRUE(table.valid());
+
+    TempDevice dev("libdm-test-dm-linear", table);
+    ASSERT_TRUE(dev.valid());
+
+    DeviceMapper& dm = DeviceMapper::Instance();
+    // Not a dm device, GetDmDeviceNameByPath will return std::nullopt.
+    ASSERT_FALSE(dm.GetDmDeviceNameByPath(loop.device()));
+    auto name = dm.GetDmDeviceNameByPath(dev.path());
+    ASSERT_EQ("libdm-test-dm-linear", *name);
+}
+
+TEST(libdm, GetParentBlockDeviceByPath) {
+    unique_fd tmp(CreateTempFile("file_1", 4096));
+    ASSERT_GE(tmp, 0);
+    LoopDevice loop(tmp, 10s);
+    ASSERT_TRUE(loop.valid());
+    ASSERT_TRUE(android::base::StartsWith(loop.device(), "/dev/block"));
+
+    DmTable table;
+    ASSERT_TRUE(table.Emplace<DmTargetLinear>(0, 1, loop.device(), 0));
+    ASSERT_TRUE(table.valid());
+
+    TempDevice dev("libdm-test-dm-linear", table);
+    ASSERT_TRUE(dev.valid());
+
+    DeviceMapper& dm = DeviceMapper::Instance();
+    ASSERT_FALSE(dm.GetParentBlockDeviceByPath(loop.device()));
+    auto sub_block_device = dm.GetParentBlockDeviceByPath(dev.path());
+    ASSERT_EQ(loop.device(), *sub_block_device);
+}
diff --git a/fs_mgr/libdm/include/libdm/dm.h b/fs_mgr/libdm/include/libdm/dm.h
index 830c5e8..418210c 100644
--- a/fs_mgr/libdm/include/libdm/dm.h
+++ b/fs_mgr/libdm/include/libdm/dm.h
@@ -214,6 +214,19 @@
 
     static std::string GetTargetType(const struct dm_target_spec& spec);
 
+    // Returns true if given path is a path to a dm block device.
+    bool IsDmBlockDevice(const std::string& path);
+
+    // Returns name of a dm-device with the given path, or std::nulloptr if given path is not a
+    // dm-device.
+    std::optional<std::string> GetDmDeviceNameByPath(const std::string& path);
+
+    // Returns a parent block device of a dm device with the given path, or std::nullopt if:
+    //  * Given path doesn't correspond to a dm device.
+    //  * A dm device is based on top of more than one block devices.
+    //  * A failure occurred.
+    std::optional<std::string> GetParentBlockDeviceByPath(const std::string& path);
+
   private:
     // Maximum possible device mapper targets registered in the kernel.
     // This is only used to read the list of targets from kernel so we allocate
diff --git a/init/persistent_properties.cpp b/init/persistent_properties.cpp
index baa9ad4..3b5a41d 100644
--- a/init/persistent_properties.cpp
+++ b/init/persistent_properties.cpp
@@ -31,10 +31,11 @@
 
 #include "util.h"
 
+using android::base::Dirname;
 using android::base::ReadFdToString;
 using android::base::StartsWith;
-using android::base::WriteStringToFd;
 using android::base::unique_fd;
+using android::base::WriteStringToFd;
 
 namespace android {
 namespace init {
@@ -191,6 +192,18 @@
         unlink(temp_filename.c_str());
         return Error(saved_errno) << "Unable to rename persistent property file";
     }
+
+    // rename() is atomic with regards to the kernel's filesystem buffers, but the parent
+    // directories must be fsync()'ed otherwise, the rename is not necessarily written to storage.
+    // Note in this case, that the source and destination directories are the same, so only one
+    // fsync() is required.
+    auto dir = Dirname(persistent_property_filename);
+    auto dir_fd = unique_fd{open(dir.c_str(), O_DIRECTORY | O_RDONLY)};
+    if (dir_fd < 0) {
+        return ErrnoError() << "Unable to open persistent properties directory for fsync()";
+    }
+    fsync(dir_fd);
+
     return {};
 }
 
diff --git a/rootdir/init.rc b/rootdir/init.rc
index ff68734..e2ecad4 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -770,6 +770,11 @@
     write /sys/fs/f2fs/${dev.mnt.blk.data}/cp_interval 200
     write /sys/fs/f2fs/${dev.mnt.blk.data}/gc_urgent_sleep_time 50
 
+    # limit discard size to 128MB in order to avoid long IO latency
+    # for filesystem tuning first (dm or sda)
+    # Note that, if dm-<num> is used, sda/mmcblk0 should be tuned in vendor/init.rc
+    write /sys/devices/virtual/block/${dev.mnt.blk.data}/queue/discard_max_bytes 134217728
+
     # Permissions for System Server and daemons.
     chown system system /sys/power/autosleep