Merge "libdm: suspend and resume devices"

am: b6c32c9051

Change-Id: Ib87712fbad318fdae9ef50728ee7a9c3da775f7b

fs_mgr/libdm/dm.cpp

@@ -162,6 +162,24 @@ DmDeviceState DeviceMapper::GetState(const std::string& name) const {
     return DmDeviceState::SUSPENDED;
 }
 
+bool DeviceMapper::ChangeState(const std::string& name, DmDeviceState state) {
+    if (state != DmDeviceState::SUSPENDED && state != DmDeviceState::ACTIVE) {
+        return false;
+    }
+
+    struct dm_ioctl io;
+    InitIo(&io, name);
+
+    if (state == DmDeviceState::SUSPENDED) io.flags = DM_SUSPEND_FLAG;
+
+    if (ioctl(fd_, DM_DEV_SUSPEND, &io) < 0) {
+        PLOG(ERROR) << "DM_DEV_SUSPEND "
+                    << (state == DmDeviceState::SUSPENDED ? "suspend" : "resume") << " failed";
+        return false;
+    }
+    return true;
+}
+
 bool DeviceMapper::CreateDevice(const std::string& name, const DmTable& table) {
     std::string ignore_path;
     if (!CreateDevice(name, table, &ignore_path, 0ms)) {

fs_mgr/libdm/dm_test.cpp

@@ -166,6 +166,34 @@ TEST(libdm, DmLinear) {
     ASSERT_TRUE(dev.Destroy());
 }
 
+TEST(libdm, DmSuspendResume) {
+    unique_fd tmp1(CreateTempFile("file_suspend_resume", 512));
+    ASSERT_GE(tmp1, 0);
+
+    LoopDevice loop_a(tmp1, 10s);
+    ASSERT_TRUE(loop_a.valid());
+
+    DmTable table;
+    ASSERT_TRUE(table.Emplace<DmTargetLinear>(0, 1, loop_a.device(), 0));
+    ASSERT_TRUE(table.valid());
+
+    TempDevice dev("libdm-test-dm-suspend-resume", table);
+    ASSERT_TRUE(dev.valid());
+    ASSERT_FALSE(dev.path().empty());
+
+    auto& dm = DeviceMapper::Instance();
+
+    // Test Set and Get status of device.
+    vector<DeviceMapper::TargetInfo> targets;
+    ASSERT_EQ(dm.GetState(dev.name()), DmDeviceState::ACTIVE);
+
+    ASSERT_TRUE(dm.ChangeState(dev.name(), DmDeviceState::SUSPENDED));
+    ASSERT_EQ(dm.GetState(dev.name()), DmDeviceState::SUSPENDED);
+
+    ASSERT_TRUE(dm.ChangeState(dev.name(), DmDeviceState::ACTIVE));
+    ASSERT_EQ(dm.GetState(dev.name()), DmDeviceState::ACTIVE);
+}
+
 TEST(libdm, DmVerityArgsAvb2) {
     std::string device = "/dev/block/platform/soc/1da4000.ufshc/by-name/vendor_a";
     std::string algorithm = "sha1";

fs_mgr/libdm/include/libdm/dm.h

@@ -79,6 +79,11 @@ class DeviceMapper final {
     // One of INVALID, SUSPENDED or ACTIVE.
     DmDeviceState GetState(const std::string& name) const;
 
+    // Puts the given device to the specified status, which must be either:
+    // - SUSPENDED: suspend the device, or
+    // - ACTIVE: resumes the device.
+    bool ChangeState(const std::string& name, DmDeviceState state);
+
     // Creates a device, loads the given table, and activates it. If the device
     // is not able to be activated, it is destroyed, and false is returned.
     // After creation, |path| contains the result of calling