Merge "libsnapshot: Add diagnostics for DM_DEV_REMOVE failures." (055f8020) · Commits · e / os / android_system_core

fastboot/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -183,6 +183,7 @@ cc_binary {
		],

		static_libs: [
		"libc++fs",
		"libgtest_prod",
		"libhealthhalutils",
		"libsnapshot_cow",

fs_mgr/libsnapshot/Android.bp

+5 −1

Original line number	Diff line number	Diff line
		@@ -264,6 +264,7 @@ cc_defaults {
		"android.hardware.boot@1.0",
		"android.hardware.boot@1.1",
		"libbrotli",
		"libc++fs",
		"libfs_mgr",
		"libgsi",
		"libgmock",
		@@ -297,6 +298,7 @@ cc_binary {
		],
		static_libs: [
		"libbrotli",
		"libc++fs",
		"libfstab",
		"libsnapshot",
		"libsnapshot_cow",
		@@ -326,6 +328,7 @@ cc_test {
		"power_test.cpp",
		],
		static_libs: [
		"libc++fs",
		"libsnapshot",
		"update_metadata-protos",
		],
		@@ -355,6 +358,7 @@ cc_defaults {
		static_libs: [
		"libbase",
		"libbrotli",
		"libc++fs",
		"libchrome",
		"libcrypto_static",
		"libcutils",

fs_mgr/libsnapshot/include/libsnapshot/snapshot.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -493,6 +493,9 @@ class SnapshotManager final : public ISnapshotManager {
		// Unmap a COW image device previously mapped with MapCowImage().
		bool UnmapCowImage(const std::string& name);

		// Unmap a COW and remove it from a MetadataBuilder.
		void UnmapAndDeleteCowPartition(MetadataBuilder* current_metadata);

		// Unmap and remove all known snapshots.
		bool RemoveAllSnapshots(LockedFile* lock);

		@@ -738,6 +741,10 @@ class SnapshotManager final : public ISnapshotManager {
		// Helper of UpdateUsesCompression
		bool UpdateUsesCompression(LockedFile* lock);

		// Wrapper around libdm, with diagnostics.
		bool DeleteDeviceIfExists(const std::string& name,
		const std::chrono::milliseconds& timeout_ms = {});

		std::string gsid_dir_;
		std::string metadata_dir_;
		std::unique_ptr<IDeviceInfo> device_;

fs_mgr/libsnapshot/snapshot.cpp

+76 −31

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@
		#include <sys/types.h>
		#include <sys/unistd.h>

		#include <filesystem>
		#include <optional>
		#include <thread>
		#include <unordered_set>
		@@ -587,8 +588,7 @@ bool SnapshotManager::MapSourceDevice(LockedFile* lock, const std::string& name,
		bool SnapshotManager::UnmapSnapshot(LockedFile* lock, const std::string& name) {
		CHECK(lock);

		auto& dm = DeviceMapper::Instance();
		if (!dm.DeleteDeviceIfExists(name)) {
		if (!DeleteDeviceIfExists(name)) {
		LOG(ERROR) << "Could not delete snapshot device: " << name;
		return false;
		}
		@@ -1252,25 +1252,6 @@ bool SnapshotManager::OnSnapshotMergeComplete(LockedFile* lock, const std::strin
		return true;
		}

		static bool DeleteDmDevice(const std::string& name, const std::chrono::milliseconds& timeout_ms) {
		auto start = std::chrono::steady_clock::now();
		auto& dm = DeviceMapper::Instance();
		while (true) {
		if (dm.DeleteDeviceIfExists(name)) {
		break;
		}
		auto now = std::chrono::steady_clock::now();
		auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - start);
		if (elapsed >= timeout_ms) {
		LOG(ERROR) << "DeleteDevice timeout: " << name;
		return false;
		}
		std::this_thread::sleep_for(400ms);
		}

		return true;
		}

		bool SnapshotManager::CollapseSnapshotDevice(const std::string& name,
		const SnapshotStatus& status) {
		auto& dm = DeviceMapper::Instance();
		@@ -1326,11 +1307,11 @@ bool SnapshotManager::CollapseSnapshotDevice(const std::string& name,
		UnmapDmUserDevice(name);
		}
		auto base_name = GetBaseDeviceName(name);
		if (!dm.DeleteDeviceIfExists(base_name)) {
		if (!DeleteDeviceIfExists(base_name)) {
		LOG(ERROR) << "Unable to delete base device for snapshot: " << base_name;
		}

		if (!DeleteDmDevice(GetSourceDeviceName(name), 4000ms)) {
		if (!DeleteDeviceIfExists(GetSourceDeviceName(name), 4000ms)) {
		LOG(ERROR) << "Unable to delete source device for snapshot: " << GetSourceDeviceName(name);
		}

		@@ -2083,15 +2064,14 @@ bool SnapshotManager::UnmapPartitionWithSnapshot(LockedFile* lock,
		return false;
		}

		auto& dm = DeviceMapper::Instance();
		auto base_name = GetBaseDeviceName(target_partition_name);
		if (!dm.DeleteDeviceIfExists(base_name)) {
		if (!DeleteDeviceIfExists(base_name)) {
		LOG(ERROR) << "Cannot delete base device: " << base_name;
		return false;
		}

		auto source_name = GetSourceDeviceName(target_partition_name);
		if (!dm.DeleteDeviceIfExists(source_name)) {
		if (!DeleteDeviceIfExists(source_name)) {
		LOG(ERROR) << "Cannot delete source device: " << source_name;
		return false;
		}
		@@ -2181,7 +2161,7 @@ bool SnapshotManager::UnmapCowDevices(LockedFile* lock, const std::string& name)
		return false;
		}

		if (!DeleteDmDevice(GetCowName(name), 4000ms)) {
		if (!DeleteDeviceIfExists(GetCowName(name), 4000ms)) {
		LOG(ERROR) << "Cannot unmap: " << GetCowName(name);
		return false;
		}
		@@ -2202,7 +2182,7 @@ bool SnapshotManager::UnmapDmUserDevice(const std::string& snapshot_name) {
		return true;
		}

		if (!dm.DeleteDeviceIfExists(dm_user_name)) {
		if (!DeleteDeviceIfExists(dm_user_name)) {
		LOG(ERROR) << "Cannot unmap " << dm_user_name;
		return false;
		}
		@@ -2593,11 +2573,10 @@ bool SnapshotManager::ForceLocalImageManager() {
		return true;
		}

		static void UnmapAndDeleteCowPartition(MetadataBuilder* current_metadata) {
		auto& dm = DeviceMapper::Instance();
		void SnapshotManager::UnmapAndDeleteCowPartition(MetadataBuilder* current_metadata) {
		std::vector<std::string> to_delete;
		for (auto* existing_cow_partition : current_metadata->ListPartitionsInGroup(kCowGroupName)) {
		if (!dm.DeleteDeviceIfExists(existing_cow_partition->name())) {
		if (!DeleteDeviceIfExists(existing_cow_partition->name())) {
		LOG(WARNING) << existing_cow_partition->name()
		<< " cannot be unmapped and its space cannot be reclaimed";
		continue;
		@@ -3626,5 +3605,71 @@ void SnapshotManager::UpdateCowStats(ISnapshotMergeStats* stats) {
		stats->set_estimated_cow_size_bytes(estimated_cow_size);
		}

		bool SnapshotManager::DeleteDeviceIfExists(const std::string& name,
		const std::chrono::milliseconds& timeout_ms) {
		auto& dm = DeviceMapper::Instance();
		auto start = std::chrono::steady_clock::now();
		while (true) {
		if (dm.DeleteDeviceIfExists(name)) {
		return true;
		}
		auto now = std::chrono::steady_clock::now();
		auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - start);
		if (elapsed >= timeout_ms) {
		break;
		}
		std::this_thread::sleep_for(400ms);
		}

		// Try to diagnose why this failed. First get the actual device path.
		std::string full_path;
		if (!dm.GetDmDevicePathByName(name, &full_path)) {
		LOG(ERROR) << "Unable to diagnose DM_DEV_REMOVE failure.";
		return false;
		}

		// Check for child dm-devices.
		std::string block_name = android::base::Basename(full_path);
		std::string sysfs_holders = "/sys/class/block/" + block_name + "/holders";

		std::error_code ec;
		std::filesystem::directory_iterator dir_iter(sysfs_holders, ec);
		if (auto begin = std::filesystem::begin(dir_iter); begin != std::filesystem::end(dir_iter)) {
		LOG(ERROR) << "Child device-mapper device still mapped: " << begin->path();
		return false;
		}

		// Check for mounted partitions.
		android::fs_mgr::Fstab fstab;
		android::fs_mgr::ReadFstabFromFile("/proc/mounts", &fstab);
		for (const auto& entry : fstab) {
		if (android::base::Basename(entry.blk_device) == block_name) {
		LOG(ERROR) << "Partition still mounted: " << entry.mount_point;
		return false;
		}
		}

		// Check for detached mounted partitions.
		for (const auto& fs : std::filesystem::directory_iterator("/sys/fs", ec)) {
		std::string fs_type = android::base::Basename(fs.path().c_str());
		if (!(fs_type == "ext4" \|\| fs_type == "f2fs")) {
		continue;
		}

		std::string path = fs.path().c_str() + "/"s + block_name;
		if (access(path.c_str(), F_OK) == 0) {
		LOG(ERROR) << "Block device was lazily unmounted and is still in-use: " << full_path
		<< "; possibly open file descriptor or attached loop device.";
		return false;
		}
		}

		LOG(ERROR) << "Device-mapper device " << name << "(" << full_path << ")"
		<< " still in use."
		<< " Probably a file descriptor was leaked or held open, or a loop device is"
		<< " attached.";
		return false;
		}

		} // namespace snapshot
		} // namespace android