Merge "libdm: add an overload of DeleteDevice accepting a timeout_ms"

fs_mgr/libdm/dm.cpp

@@ -20,6 +20,7 @@
 #include <sys/sysmacros.h>
 #include <sys/types.h>
 
+#include <chrono>
 #include <functional>
 #include <thread>
 
@@ -79,14 +80,24 @@ bool DeviceMapper::CreateDevice(const std::string& name, const std::string& uuid
     return true;
 }
 
-bool DeviceMapper::DeleteDeviceIfExists(const std::string& name) {
+bool DeviceMapper::DeleteDeviceIfExists(const std::string& name,
+                                        const std::chrono::milliseconds& timeout_ms) {
     if (GetState(name) == DmDeviceState::INVALID) {
         return true;
     }
-    return DeleteDevice(name);
+    return DeleteDevice(name, timeout_ms);
 }
 
-bool DeviceMapper::DeleteDevice(const std::string& name) {
+bool DeviceMapper::DeleteDeviceIfExists(const std::string& name) {
+    return DeleteDeviceIfExists(name, 0ms);
+}
+
+bool DeviceMapper::DeleteDevice(const std::string& name,
+                                const std::chrono::milliseconds& timeout_ms) {
+    std::string unique_path;
+    if (!GetDeviceUniquePath(name, &unique_path)) {
+        LOG(ERROR) << "Failed to get unique path for device " << name;
+    }
     struct dm_ioctl io;
     InitIo(&io, name);
 
@@ -100,9 +111,23 @@ bool DeviceMapper::DeleteDevice(const std::string& name) {
     CHECK(io.flags & DM_UEVENT_GENERATED_FLAG)
             << "Didn't generate uevent for [" << name << "] removal";
 
+    if (timeout_ms <= std::chrono::milliseconds::zero()) {
+        return true;
+    }
+    if (unique_path.empty()) {
+        return false;
+    }
+    if (!WaitForFileDeleted(unique_path, timeout_ms)) {
+        LOG(ERROR) << "Timeout out waiting for " << unique_path << " to be deleted";
+        return false;
+    }
     return true;
 }
 
+bool DeviceMapper::DeleteDevice(const std::string& name) {
+    return DeleteDevice(name, 0ms);
+}
+
 static std::string GenerateUuid() {
     uuid_t uuid_bytes;
     uuid_generate(uuid_bytes);

fs_mgr/libdm/dm_test.cpp

@@ -520,3 +520,27 @@ TEST(libdm, DefaultKeyArgs) {
     ASSERT_TRUE(target.Valid());
     ASSERT_EQ(target.GetParameterString(), "AES-256-XTS abcdef0123456789 /dev/loop0 0");
 }
+
+TEST(libdm, DeleteDeviceWithTimeout) {
+    unique_fd tmp(CreateTempFile("file_1", 4096));
+    ASSERT_GE(tmp, 0);
+    LoopDevice loop(tmp, 10s);
+    ASSERT_TRUE(loop.valid());
+
+    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();
+
+    std::string path;
+    ASSERT_TRUE(dm.GetDmDevicePathByName("libdm-test-dm-linear", &path));
+    ASSERT_EQ(0, access(path.c_str(), F_OK));
+
+    ASSERT_TRUE(dm.DeleteDevice("libdm-test-dm-linear", 5s));
+    ASSERT_EQ(DmDeviceState::INVALID, dm.GetState("libdm-test-dm-linear"));
+    ASSERT_NE(0, access(path.c_str(), F_OK));
+    ASSERT_EQ(ENOENT, errno);
+}

fs_mgr/libdm/include/libdm/dm.h

@@ -90,6 +90,10 @@ class DeviceMapper final {
     // Returns 'true' on success, false otherwise.
     bool DeleteDevice(const std::string& name);
     bool DeleteDeviceIfExists(const std::string& name);
+    // Removes a device mapper device with the given name and waits for |timeout_ms| milliseconds
+    // for the corresponding block device to be deleted.
+    bool DeleteDevice(const std::string& name, const std::chrono::milliseconds& timeout_ms);
+    bool DeleteDeviceIfExists(const std::string& name, const std::chrono::milliseconds& timeout_ms);
 
     // Fetches and returns the complete state of the underlying device mapper
     // device with given name.

fs_mgr/libdm/utility.cpp

@@ -52,5 +52,15 @@ bool WaitForFile(const std::string& path, const std::chrono::milliseconds& timeo
     return WaitForCondition(condition, timeout_ms);
 }
 
+bool WaitForFileDeleted(const std::string& path, const std::chrono::milliseconds& timeout_ms) {
+    auto condition = [&]() -> WaitResult {
+        if (access(path.c_str(), F_OK) == 0 || errno != ENOENT) {
+            return WaitResult::Wait;
+        }
+        return WaitResult::Done;
+    };
+    return WaitForCondition(condition, timeout_ms);
+}
+
 }  // namespace dm
 }  // namespace android

fs_mgr/libdm/utility.h

@@ -23,6 +23,7 @@ namespace dm {
 enum class WaitResult { Wait, Done, Fail };
 
 bool WaitForFile(const std::string& path, const std::chrono::milliseconds& timeout_ms);
+bool WaitForFileDeleted(const std::string& path, const std::chrono::milliseconds& timeout_ms);
 bool WaitForCondition(const std::function<WaitResult()>& condition,
                       const std::chrono::milliseconds& timeout_ms);