Merge "ueventd: allow using external firmware handlers"
diff --git a/adb/adb.cpp b/adb/adb.cpp
index ba6df7a..1ec145b 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -1131,7 +1131,9 @@
if (service == "features") {
std::string error;
- atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+ atransport* t =
+ s->transport ? s->transport
+ : acquire_one_transport(type, serial, transport_id, nullptr, &error);
if (t != nullptr) {
SendOkay(reply_fd, FeatureSetToString(t->features()));
} else {
@@ -1190,7 +1192,9 @@
// These always report "unknown" rather than the actual error, for scripts.
if (service == "get-serialno") {
std::string error;
- atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+ atransport* t =
+ s->transport ? s->transport
+ : acquire_one_transport(type, serial, transport_id, nullptr, &error);
if (t) {
SendOkay(reply_fd, !t->serial.empty() ? t->serial : "unknown");
} else {
@@ -1200,7 +1204,9 @@
}
if (service == "get-devpath") {
std::string error;
- atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+ atransport* t =
+ s->transport ? s->transport
+ : acquire_one_transport(type, serial, transport_id, nullptr, &error);
if (t) {
SendOkay(reply_fd, !t->devpath.empty() ? t->devpath : "unknown");
} else {
@@ -1210,7 +1216,9 @@
}
if (service == "get-state") {
std::string error;
- atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &error);
+ atransport* t =
+ s->transport ? s->transport
+ : acquire_one_transport(type, serial, transport_id, nullptr, &error);
if (t) {
SendOkay(reply_fd, t->connection_state_name());
} else {
@@ -1234,7 +1242,9 @@
if (service == "reconnect") {
std::string response;
- atransport* t = acquire_one_transport(type, serial, transport_id, nullptr, &response, true);
+ atransport* t = s->transport ? s->transport
+ : acquire_one_transport(type, serial, transport_id, nullptr,
+ &response, true);
if (t != nullptr) {
kick_transport(t, true);
response =
@@ -1246,8 +1256,15 @@
// TODO: Switch handle_forward_request to string_view.
std::string service_str(service);
- if (handle_forward_request(
- service_str.c_str(), [=](std::string* error) { return s->transport; }, reply_fd)) {
+ auto transport_acquirer = [=](std::string* error) {
+ if (s->transport) {
+ return s->transport;
+ } else {
+ std::string error;
+ return acquire_one_transport(type, serial, transport_id, nullptr, &error);
+ }
+ };
+ if (handle_forward_request(service_str.c_str(), transport_acquirer, reply_fd)) {
return HostRequestResult::Handled;
}
diff --git a/adb/sockets.cpp b/adb/sockets.cpp
index 75993b3..e78530c 100644
--- a/adb/sockets.cpp
+++ b/adb/sockets.cpp
@@ -757,6 +757,8 @@
#if ADB_HOST
service = std::string_view(s->smart_socket_data).substr(4);
+
+ // TODO: These should be handled in handle_host_request.
if (android::base::ConsumePrefix(&service, "host-serial:")) {
// serial number should follow "host:" and could be a host:port string.
if (!internal::parse_host_service(&serial, &service, service)) {
diff --git a/adb/test_device.py b/adb/test_device.py
index f95a5b3..dbd80ed 100755
--- a/adb/test_device.py
+++ b/adb/test_device.py
@@ -139,6 +139,25 @@
msg = self.device.forward_list()
self.assertEqual('', msg.strip())
+ def test_forward_old_protocol(self):
+ serialno = subprocess.check_output(self.device.adb_cmd + ['get-serialno']).strip()
+
+ msg = self.device.forward_list()
+ self.assertEqual('', msg.strip(),
+ 'Forwarding list must be empty to run this test.')
+
+ s = socket.create_connection(("localhost", 5037))
+ service = b"host-serial:%s:forward:tcp:5566;tcp:6655" % serialno
+ cmd = b"%04x%s" % (len(service), service)
+ s.sendall(cmd)
+
+ msg = self.device.forward_list()
+ self.assertTrue(re.search(r'tcp:5566.+tcp:6655', msg))
+
+ self.device.forward_remove_all()
+ msg = self.device.forward_list()
+ self.assertEqual('', msg.strip())
+
def test_forward_tcp_port_0(self):
self.assertEqual('', self.device.forward_list().strip(),
'Forwarding list must be empty to run this test.')
diff --git a/base/Android.bp b/base/Android.bp
index 357ce01..f5000c1 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -20,8 +20,14 @@
"-Wall",
"-Werror",
"-Wextra",
- "-D_FILE_OFFSET_BITS=64",
],
+ target: {
+ android: {
+ cflags: [
+ "-D_FILE_OFFSET_BITS=64",
+ ],
+ },
+ },
}
cc_library_headers {
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index 978eed0..546bce2 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -143,6 +143,10 @@
static_libs: [
"libhealthhalutils",
],
+
+ header_libs: [
+ "libsnapshot_headers",
+ ]
}
cc_defaults {
diff --git a/fastboot/device/flashing.cpp b/fastboot/device/flashing.cpp
index 99854c9..102ebdb 100644
--- a/fastboot/device/flashing.cpp
+++ b/fastboot/device/flashing.cpp
@@ -32,6 +32,7 @@
#include <fstab/fstab.h>
#include <liblp/builder.h>
#include <liblp/liblp.h>
+#include <libsnapshot/snapshot.h>
#include <sparse/sparse.h>
#include "fastboot_device.h"
@@ -171,6 +172,11 @@
if (!slot_suffix.empty() && GetPartitionSlotSuffix(partition_name) == slot_suffix) {
continue;
}
+ std::string group_name = GetPartitionGroupName(old_metadata->groups[partition.group_index]);
+ // Skip partitions in the COW group
+ if (group_name == android::snapshot::kCowGroupName) {
+ continue;
+ }
partitions_to_keep.emplace(partition_name);
}
diff --git a/fs_mgr/fs_mgr_dm_linear.cpp b/fs_mgr/fs_mgr_dm_linear.cpp
index ea799ce..0dcb9fe 100644
--- a/fs_mgr/fs_mgr_dm_linear.cpp
+++ b/fs_mgr/fs_mgr_dm_linear.cpp
@@ -79,22 +79,22 @@
return true;
}
-bool CreateDmTable(const IPartitionOpener& opener, const LpMetadata& metadata,
- const LpMetadataPartition& partition, const std::string& super_device,
- DmTable* table) {
+bool CreateDmTableInternal(const CreateLogicalPartitionParams& params, DmTable* table) {
+ const auto& super_device = params.block_device;
+
uint64_t sector = 0;
- for (size_t i = 0; i < partition.num_extents; i++) {
- const auto& extent = metadata.extents[partition.first_extent_index + i];
+ for (size_t i = 0; i < params.partition->num_extents; i++) {
+ const auto& extent = params.metadata->extents[params.partition->first_extent_index + i];
std::unique_ptr<DmTarget> target;
switch (extent.target_type) {
case LP_TARGET_TYPE_ZERO:
target = std::make_unique<DmTargetZero>(sector, extent.num_sectors);
break;
case LP_TARGET_TYPE_LINEAR: {
- const auto& block_device = metadata.block_devices[extent.target_source];
+ const auto& block_device = params.metadata->block_devices[extent.target_source];
std::string dev_string;
- if (!GetPhysicalPartitionDevicePath(opener, metadata, block_device, super_device,
- &dev_string)) {
+ if (!GetPhysicalPartitionDevicePath(*params.partition_opener, *params.metadata,
+ block_device, super_device, &dev_string)) {
LOG(ERROR) << "Unable to complete device-mapper table, unknown block device";
return false;
}
@@ -111,12 +111,21 @@
}
sector += extent.num_sectors;
}
- if (partition.attributes & LP_PARTITION_ATTR_READONLY) {
+ if (params.partition->attributes & LP_PARTITION_ATTR_READONLY) {
table->set_readonly(true);
}
+ if (params.force_writable) {
+ table->set_readonly(false);
+ }
return true;
}
+bool CreateDmTable(CreateLogicalPartitionParams params, DmTable* table) {
+ CreateLogicalPartitionParams::OwnedData owned_data;
+ if (!params.InitDefaults(&owned_data)) return false;
+ return CreateDmTableInternal(params, table);
+}
+
bool CreateLogicalPartitions(const std::string& block_device) {
uint32_t slot = SlotNumberForSlotSuffix(fs_mgr_get_slot_suffix());
auto metadata = ReadMetadata(block_device.c_str(), slot);
@@ -160,6 +169,11 @@
return false;
}
+ if (!partition_opener) {
+ owned->partition_opener = std::make_unique<PartitionOpener>();
+ partition_opener = owned->partition_opener.get();
+ }
+
// Read metadata if needed.
if (!metadata) {
if (!metadata_slot) {
@@ -167,7 +181,8 @@
return false;
}
auto slot = *metadata_slot;
- if (owned->metadata = ReadMetadata(block_device, slot); !owned->metadata) {
+ if (owned->metadata = ReadMetadata(*partition_opener, block_device, slot);
+ !owned->metadata) {
LOG(ERROR) << "Could not read partition table for: " << block_device;
return false;
}
@@ -195,11 +210,6 @@
return false;
}
- if (!partition_opener) {
- owned->partition_opener = std::make_unique<PartitionOpener>();
- partition_opener = owned->partition_opener.get();
- }
-
if (device_name.empty()) {
device_name = partition_name;
}
@@ -212,13 +222,9 @@
if (!params.InitDefaults(&owned_data)) return false;
DmTable table;
- if (!CreateDmTable(*params.partition_opener, *params.metadata, *params.partition,
- params.block_device, &table)) {
+ if (!CreateDmTableInternal(params, &table)) {
return false;
}
- if (params.force_writable) {
- table.set_readonly(false);
- }
DeviceMapper& dm = DeviceMapper::Instance();
if (!dm.CreateDevice(params.device_name, table, path, params.timeout_ms)) {
diff --git a/fs_mgr/include/fs_mgr_dm_linear.h b/fs_mgr/include/fs_mgr_dm_linear.h
index a912208..f3d09fb 100644
--- a/fs_mgr/include/fs_mgr_dm_linear.h
+++ b/fs_mgr/include/fs_mgr_dm_linear.h
@@ -105,9 +105,7 @@
bool DestroyLogicalPartition(const std::string& name);
// Helper for populating a DmTable for a logical partition.
-bool CreateDmTable(const IPartitionOpener& opener, const LpMetadata& metadata,
- const LpMetadataPartition& partition, const std::string& super_device,
- android::dm::DmTable* table);
+bool CreateDmTable(CreateLogicalPartitionParams params, android::dm::DmTable* table);
} // namespace fs_mgr
} // namespace android
diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index c5d6a3b..ea3b58e 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -40,6 +40,10 @@
return true;
}
+Interval LinearExtent::AsInterval() const {
+ return Interval(device_index(), physical_sector(), end_sector());
+}
+
bool ZeroExtent::AddTo(LpMetadata* out) const {
out->extents.emplace_back(LpMetadataExtent{num_sectors_, LP_TARGET_TYPE_ZERO, 0, 0});
return true;
@@ -96,6 +100,20 @@
DCHECK(size_ == aligned_size);
}
+Partition Partition::GetBeginningExtents(uint64_t aligned_size) const {
+ Partition p(name_, group_name_, attributes_);
+ for (const auto& extent : extents_) {
+ auto le = extent->AsLinearExtent();
+ if (le) {
+ p.AddExtent(std::make_unique<LinearExtent>(*le));
+ } else {
+ p.AddExtent(std::make_unique<ZeroExtent>(extent->num_sectors()));
+ }
+ }
+ p.ShrinkTo(aligned_size);
+ return p;
+}
+
uint64_t Partition::BytesOnDisk() const {
uint64_t sectors = 0;
for (const auto& extent : extents_) {
@@ -602,6 +620,10 @@
return ret;
}
+std::unique_ptr<Extent> Interval::AsExtent() const {
+ return std::make_unique<LinearExtent>(length(), device_index, start);
+}
+
bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t aligned_size,
const std::vector<Interval>& free_region_hint) {
uint64_t space_needed = aligned_size - partition->size();
@@ -1168,5 +1190,9 @@
: "";
}
+uint64_t MetadataBuilder::logical_block_size() const {
+ return geometry_.logical_block_size;
+}
+
} // namespace fs_mgr
} // namespace android
diff --git a/fs_mgr/liblp/include/liblp/builder.h b/fs_mgr/liblp/include/liblp/builder.h
index 6f2ab75..69885fe 100644
--- a/fs_mgr/liblp/include/liblp/builder.h
+++ b/fs_mgr/liblp/include/liblp/builder.h
@@ -33,10 +33,11 @@
namespace fs_mgr {
class LinearExtent;
+struct Interval;
// By default, partitions are aligned on a 1MiB boundary.
-static const uint32_t kDefaultPartitionAlignment = 1024 * 1024;
-static const uint32_t kDefaultBlockSize = 4096;
+static constexpr uint32_t kDefaultPartitionAlignment = 1024 * 1024;
+static constexpr uint32_t kDefaultBlockSize = 4096;
// Name of the default group in a metadata.
static constexpr std::string_view kDefaultGroup = "default";
@@ -74,6 +75,8 @@
return sector >= physical_sector_ && sector < end_sector();
}
+ Interval AsInterval() const;
+
private:
uint32_t device_index_;
uint64_t physical_sector_;
@@ -127,6 +130,12 @@
const std::vector<std::unique_ptr<Extent>>& extents() const { return extents_; }
uint64_t size() const { return size_; }
+ // Return a copy of *this, but with extents that includes only the first
+ // |aligned_size| bytes. |aligned_size| should be aligned to
+ // logical_block_size() of the MetadataBuilder that this partition belongs
+ // to.
+ Partition GetBeginningExtents(uint64_t aligned_size) const;
+
private:
void ShrinkTo(uint64_t aligned_size);
void set_group_name(std::string_view group_name) { group_name_ = group_name; }
@@ -156,6 +165,8 @@
return (start == other.start) ? end < other.end : start < other.start;
}
+ std::unique_ptr<Extent> AsExtent() const;
+
// Intersect |a| with |b|.
// If no intersection, result has 0 length().
static Interval Intersect(const Interval& a, const Interval& b);
@@ -325,6 +336,8 @@
// Return the list of free regions not occupied by extents in the metadata.
std::vector<Interval> GetFreeRegions() const;
+ uint64_t logical_block_size() const;
+
private:
MetadataBuilder();
MetadataBuilder(const MetadataBuilder&) = delete;
diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index 8df9c52..f2b6141 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -25,10 +25,12 @@
shared_libs: [
"libbase",
"liblog",
+ "liblp",
],
static_libs: [
"libdm",
"libfs_mgr",
+ "libfstab",
"liblp",
],
whole_static_libs: [
@@ -49,10 +51,17 @@
name: "libsnapshot_sources",
srcs: [
"snapshot.cpp",
+ "partition_cow_creator.cpp",
"utility.cpp",
],
}
+cc_library_headers {
+ name: "libsnapshot_headers",
+ recovery_available: true,
+ defaults: ["libsnapshot_defaults"],
+}
+
cc_library_static {
name: "libsnapshot",
defaults: ["libsnapshot_defaults"],
@@ -77,6 +86,7 @@
defaults: ["libsnapshot_defaults"],
srcs: [
"snapshot_test.cpp",
+ "partition_cow_creator_test.cpp",
"test_helpers.cpp",
],
shared_libs: [
@@ -90,5 +100,7 @@
"libgmock",
"liblp",
"libsnapshot",
+ "libsparse",
+ "libz",
],
}
diff --git a/fs_mgr/libsnapshot/digital_storage.h b/fs_mgr/libsnapshot/digital_storage.h
new file mode 100644
index 0000000..210298e
--- /dev/null
+++ b/fs_mgr/libsnapshot/digital_storage.h
@@ -0,0 +1,77 @@
+// 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.
+
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+
+namespace android {
+namespace digital_storage {
+
+template <size_t Power>
+struct Size {
+ static constexpr size_t power = Power;
+ constexpr Size(uint64_t count) : value_(count) {}
+
+ constexpr uint64_t bytes() const { return value_ << (Power * 10); }
+ constexpr uint64_t count() const { return value_; }
+ operator uint64_t() const { return bytes(); }
+
+ private:
+ uint64_t value_;
+};
+
+using B = Size<0>;
+using KiB = Size<1>;
+using MiB = Size<2>;
+using GiB = Size<3>;
+
+constexpr B operator""_B(unsigned long long v) { // NOLINT
+ return B{v};
+}
+
+constexpr KiB operator""_KiB(unsigned long long v) { // NOLINT
+ return KiB{v};
+}
+
+constexpr MiB operator""_MiB(unsigned long long v) { // NOLINT
+ return MiB{v};
+}
+
+constexpr GiB operator""_GiB(unsigned long long v) { // NOLINT
+ return GiB{v};
+}
+
+template <typename Dest, typename Src>
+constexpr Dest size_cast(Src src) {
+ if (Src::power < Dest::power) {
+ return Dest(src.count() >> ((Dest::power - Src::power) * 10));
+ }
+ if (Src::power > Dest::power) {
+ return Dest(src.count() << ((Src::power - Dest::power) * 10));
+ }
+ return Dest(src.count());
+}
+
+static_assert((1_B).bytes() == 1);
+static_assert((1_KiB).bytes() == 1 << 10);
+static_assert((1_MiB).bytes() == 1 << 20);
+static_assert((1_GiB).bytes() == 1 << 30);
+static_assert(size_cast<KiB>(1_B).count() == 0);
+static_assert(size_cast<KiB>(1024_B).count() == 1);
+static_assert(size_cast<KiB>(1_MiB).count() == 1024);
+
+} // namespace digital_storage
+} // namespace android
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index c41a951..6bc09a1 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -17,13 +17,17 @@
#include <stdint.h>
#include <chrono>
+#include <map>
#include <memory>
#include <string>
+#include <string_view>
#include <vector>
#include <android-base/unique_fd.h>
+#include <fs_mgr_dm_linear.h>
#include <libdm/dm.h>
#include <libfiemap/image_manager.h>
+#include <liblp/builder.h>
#include <liblp/liblp.h>
#ifndef FRIEND_TEST
@@ -45,6 +49,13 @@
namespace snapshot {
+struct AutoDeleteCowImage;
+struct AutoDeleteSnapshot;
+struct PartitionCowCreator;
+struct AutoDeviceList;
+
+static constexpr const std::string_view kCowGroupName = "cow";
+
enum class UpdateState : unsigned int {
// No update or merge is in progress.
None,
@@ -75,8 +86,9 @@
class SnapshotManager final {
using CreateLogicalPartitionParams = android::fs_mgr::CreateLogicalPartitionParams;
- using LpMetadata = android::fs_mgr::LpMetadata;
using IPartitionOpener = android::fs_mgr::IPartitionOpener;
+ using LpMetadata = android::fs_mgr::LpMetadata;
+ using MetadataBuilder = android::fs_mgr::MetadataBuilder;
public:
// Dependency injection for testing.
@@ -88,6 +100,7 @@
virtual std::string GetSlotSuffix() const = 0;
virtual std::string GetSuperDevice(uint32_t slot) const = 0;
virtual const IPartitionOpener& GetPartitionOpener() const = 0;
+ virtual bool IsOverlayfsSetup() const = 0;
};
~SnapshotManager();
@@ -153,6 +166,20 @@
// Other: 0
UpdateState GetUpdateState(double* progress = nullptr);
+ // Create necessary COW device / files for OTA clients. New logical partitions will be added to
+ // group "cow" in target_metadata. Regions of partitions of current_metadata will be
+ // "write-protected" and snapshotted.
+ bool CreateUpdateSnapshots(MetadataBuilder* target_metadata, const std::string& target_suffix,
+ MetadataBuilder* current_metadata, const std::string& current_suffix,
+ const std::map<std::string, uint64_t>& cow_sizes);
+
+ // Map a snapshotted partition for OTA clients to write to. Write-protected regions are
+ // determined previously in CreateSnapshots.
+ bool MapUpdateSnapshot(const CreateLogicalPartitionParams& params, std::string* snapshot_path);
+
+ // Unmap a snapshot device that's previously mapped with MapUpdateSnapshot.
+ bool UnmapUpdateSnapshot(const std::string& target_partition_name);
+
// If this returns true, first-stage mount must call
// CreateLogicalAndSnapshotPartitions rather than CreateLogicalPartitions.
bool NeedSnapshotsInFirstStageMount();
@@ -173,7 +200,12 @@
FRIEND_TEST(SnapshotTest, Merge);
FRIEND_TEST(SnapshotTest, MergeCannotRemoveCow);
FRIEND_TEST(SnapshotTest, NoMergeBeforeReboot);
+ FRIEND_TEST(SnapshotUpdateTest, SnapshotStatusFileWithoutCow);
friend class SnapshotTest;
+ friend class SnapshotUpdateTest;
+ friend struct AutoDeleteCowImage;
+ friend struct AutoDeleteSnapshot;
+ friend struct PartitionCowCreator;
using DmTargetSnapshot = android::dm::DmTargetSnapshot;
using IImageManager = android::fiemap::IImageManager;
@@ -241,9 +273,8 @@
// be mapped with two table entries: a dm-snapshot range covering
// snapshot_size, and a dm-linear range covering the remainder.
//
- // All sizes are specified in bytes, and the device, snapshot and COW partition sizes
- // must be a multiple of the sector size (512 bytes). COW file size will be rounded up
- // to the nearest sector.
+ // All sizes are specified in bytes, and the device, snapshot, COW partition and COW file sizes
+ // must be a multiple of the sector size (512 bytes).
bool CreateSnapshot(LockedFile* lock, const std::string& name, SnapshotStatus status);
// |name| should be the base partition name (e.g. "system_a"). Create the
@@ -262,8 +293,7 @@
std::string* dev_path);
// Map a COW image that was previous created with CreateCowImage.
- bool MapCowImage(const std::string& name, const std::chrono::milliseconds& timeout_ms,
- std::string* cow_image_device);
+ bool MapCowImage(const std::string& name, const std::chrono::milliseconds& timeout_ms);
// Remove the backing copy-on-write image and snapshot states for the named snapshot. The
// caller is responsible for ensuring that the snapshot is unmapped.
@@ -344,6 +374,24 @@
bool MapPartitionWithSnapshot(LockedFile* lock, CreateLogicalPartitionParams params,
std::string* path);
+ // Map the COW devices, including the partition in super and the images.
+ // |params|:
+ // - |partition_name| should be the name of the top-level partition (e.g. system_b),
+ // not system_b-cow-img
+ // - |device_name| and |partition| is ignored
+ // - |timeout_ms| and the rest is respected
+ // Return the path in |cow_device_path| (e.g. /dev/block/dm-1) and major:minor in
+ // |cow_device_string|
+ bool MapCowDevices(LockedFile* lock, const CreateLogicalPartitionParams& params,
+ const SnapshotStatus& snapshot_status, AutoDeviceList* created_devices,
+ std::string* cow_name);
+
+ // The reverse of MapCowDevices.
+ bool UnmapCowDevices(LockedFile* lock, const std::string& name);
+
+ // The reverse of MapPartitionWithSnapshot.
+ bool UnmapPartitionWithSnapshot(LockedFile* lock, const std::string& target_partition_name);
+
std::string gsid_dir_;
std::string metadata_dir_;
std::unique_ptr<IDeviceInfo> device_;
diff --git a/fs_mgr/libsnapshot/partition_cow_creator.cpp b/fs_mgr/libsnapshot/partition_cow_creator.cpp
new file mode 100644
index 0000000..44d8860
--- /dev/null
+++ b/fs_mgr/libsnapshot/partition_cow_creator.cpp
@@ -0,0 +1,176 @@
+// 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 "partition_cow_creator.h"
+
+#include <math.h>
+
+#include <android-base/logging.h>
+
+#include "utility.h"
+
+using android::dm::kSectorSize;
+using android::fs_mgr::Extent;
+using android::fs_mgr::Interval;
+using android::fs_mgr::kDefaultBlockSize;
+using android::fs_mgr::Partition;
+
+namespace android {
+namespace snapshot {
+
+// Round |d| up to a multiple of |block_size|.
+static uint64_t RoundUp(double d, uint64_t block_size) {
+ uint64_t ret = ((uint64_t)ceil(d) + block_size - 1) / block_size * block_size;
+ CHECK(ret >= d) << "Can't round " << d << " up to a multiple of " << block_size;
+ return ret;
+}
+
+// Intersect two linear extents. If no intersection, return an extent with length 0.
+static std::unique_ptr<Extent> Intersect(Extent* target_extent, Extent* existing_extent) {
+ // Convert target_extent and existing_extent to linear extents. Zero extents
+ // doesn't matter and doesn't result in any intersection.
+ auto existing_linear_extent = existing_extent->AsLinearExtent();
+ if (!existing_extent) return nullptr;
+
+ auto target_linear_extent = target_extent->AsLinearExtent();
+ if (!target_linear_extent) return nullptr;
+
+ return Interval::Intersect(target_linear_extent->AsInterval(),
+ existing_linear_extent->AsInterval())
+ .AsExtent();
+}
+
+// Check that partition |p| contains |e| fully. Both of them should
+// be from |target_metadata|.
+// Returns true as long as |e| is a subrange of any extent of |p|.
+bool PartitionCowCreator::HasExtent(Partition* p, Extent* e) {
+ for (auto& partition_extent : p->extents()) {
+ auto intersection = Intersect(partition_extent.get(), e);
+ if (intersection != nullptr && intersection->num_sectors() == e->num_sectors()) {
+ return true;
+ }
+ }
+ return false;
+}
+
+// Return the number of sectors, N, where |target_partition|[0..N] (from
+// |target_metadata|) are the sectors that should be snapshotted. N is computed
+// so that this range of sectors are used by partitions in |current_metadata|.
+//
+// The client code (update_engine) should have computed target_metadata by
+// resizing partitions of current_metadata, so only the first N sectors should
+// be snapshotted, not a range with start index != 0.
+//
+// Note that if partition A has shrunk and partition B has grown, the new
+// extents of partition B may use the empty space that was used by partition A.
+// In this case, that new extent cannot be written directly, as it may be used
+// by the running system. Hence, all extents of the new partition B must be
+// intersected with all old partitions (including old partition A and B) to get
+// the region that needs to be snapshotted.
+std::optional<uint64_t> PartitionCowCreator::GetSnapshotSize() {
+ // Compute the number of sectors that needs to be snapshotted.
+ uint64_t snapshot_sectors = 0;
+ std::vector<std::unique_ptr<Extent>> intersections;
+ for (const auto& extent : target_partition->extents()) {
+ for (auto* existing_partition :
+ ListPartitionsWithSuffix(current_metadata, current_suffix)) {
+ for (const auto& existing_extent : existing_partition->extents()) {
+ auto intersection = Intersect(extent.get(), existing_extent.get());
+ if (intersection != nullptr && intersection->num_sectors() > 0) {
+ snapshot_sectors += intersection->num_sectors();
+ intersections.emplace_back(std::move(intersection));
+ }
+ }
+ }
+ }
+ uint64_t snapshot_size = snapshot_sectors * kSectorSize;
+
+ // Sanity check that all recorded intersections are indeed within
+ // target_partition[0..snapshot_sectors].
+ Partition target_partition_snapshot = target_partition->GetBeginningExtents(snapshot_size);
+ for (const auto& intersection : intersections) {
+ if (!HasExtent(&target_partition_snapshot, intersection.get())) {
+ auto linear_intersection = intersection->AsLinearExtent();
+ LOG(ERROR) << "Extent "
+ << (linear_intersection
+ ? (std::to_string(linear_intersection->physical_sector()) + "," +
+ std::to_string(linear_intersection->end_sector()))
+ : "")
+ << " is not part of Partition " << target_partition->name() << "[0.."
+ << snapshot_size
+ << "]. The metadata wasn't constructed correctly. This should not happen.";
+ return std::nullopt;
+ }
+ }
+
+ return snapshot_size;
+}
+
+std::optional<PartitionCowCreator::Return> PartitionCowCreator::Run() {
+ static constexpr double kCowEstimateFactor = 1.05;
+
+ CHECK(current_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME &&
+ target_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME);
+
+ uint64_t logical_block_size = current_metadata->logical_block_size();
+ CHECK(logical_block_size != 0 && !(logical_block_size & (logical_block_size - 1)))
+ << "logical_block_size is not power of 2";
+
+ Return ret;
+ ret.snapshot_status.device_size = target_partition->size();
+
+ auto snapshot_size = GetSnapshotSize();
+ if (!snapshot_size.has_value()) return std::nullopt;
+
+ ret.snapshot_status.snapshot_size = *snapshot_size;
+
+ // TODO: always read from cow_size when the COW size is written in
+ // update package. kCowEstimateFactor is good for prototyping but
+ // we can't use that in production.
+ if (!cow_size.has_value()) {
+ cow_size =
+ RoundUp(ret.snapshot_status.snapshot_size * kCowEstimateFactor, kDefaultBlockSize);
+ }
+
+ // Compute regions that are free in both current and target metadata. These are the regions
+ // we can use for COW partition.
+ auto target_free_regions = target_metadata->GetFreeRegions();
+ auto current_free_regions = current_metadata->GetFreeRegions();
+ auto free_regions = Interval::Intersect(target_free_regions, current_free_regions);
+ uint64_t free_region_length = 0;
+ for (const auto& interval : free_regions) {
+ free_region_length += interval.length() * kSectorSize;
+ }
+
+ LOG(INFO) << "Remaining free space for COW: " << free_region_length << " bytes";
+
+ // Compute the COW partition size.
+ ret.snapshot_status.cow_partition_size = std::min(*cow_size, free_region_length);
+ // Round it down to the nearest logical block. Logical partitions must be a multiple
+ // of logical blocks.
+ ret.snapshot_status.cow_partition_size &= ~(logical_block_size - 1);
+ // Assign cow_partition_usable_regions to indicate what regions should the COW partition uses.
+ ret.cow_partition_usable_regions = std::move(free_regions);
+
+ // The rest of the COW space is allocated on ImageManager.
+ ret.snapshot_status.cow_file_size = (*cow_size) - ret.snapshot_status.cow_partition_size;
+ // Round it up to the nearest sector.
+ ret.snapshot_status.cow_file_size += kSectorSize - 1;
+ ret.snapshot_status.cow_file_size &= ~(kSectorSize - 1);
+
+ return ret;
+}
+
+} // namespace snapshot
+} // namespace android
diff --git a/fs_mgr/libsnapshot/partition_cow_creator.h b/fs_mgr/libsnapshot/partition_cow_creator.h
new file mode 100644
index 0000000..a235914
--- /dev/null
+++ b/fs_mgr/libsnapshot/partition_cow_creator.h
@@ -0,0 +1,63 @@
+// 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.
+
+#pragma once
+
+#include <stdint.h>
+
+#include <optional>
+#include <string>
+
+#include <liblp/builder.h>
+
+#include <libsnapshot/snapshot.h>
+
+namespace android {
+namespace snapshot {
+
+// Helper class that creates COW for a partition.
+struct PartitionCowCreator {
+ using Extent = android::fs_mgr::Extent;
+ using Interval = android::fs_mgr::Interval;
+ using MetadataBuilder = android::fs_mgr::MetadataBuilder;
+ using Partition = android::fs_mgr::Partition;
+
+ // The metadata that will be written to target metadata slot.
+ MetadataBuilder* target_metadata;
+ // The suffix of the target slot.
+ std::string target_suffix;
+ // The partition in target_metadata that needs to be snapshotted.
+ Partition* target_partition;
+ // The metadata at the current slot (that would be used if the device boots
+ // normally). This is used to determine which extents are being used.
+ MetadataBuilder* current_metadata;
+ // The suffix of the current slot.
+ std::string current_suffix;
+ // The COW size given by client code.
+ std::optional<uint64_t> cow_size;
+
+ struct Return {
+ SnapshotManager::SnapshotStatus snapshot_status;
+ std::vector<Interval> cow_partition_usable_regions;
+ };
+
+ std::optional<Return> Run();
+
+ private:
+ bool HasExtent(Partition* p, Extent* e);
+ std::optional<uint64_t> GetSnapshotSize();
+};
+
+} // namespace snapshot
+} // namespace android
diff --git a/fs_mgr/libsnapshot/partition_cow_creator_test.cpp b/fs_mgr/libsnapshot/partition_cow_creator_test.cpp
new file mode 100644
index 0000000..e308943
--- /dev/null
+++ b/fs_mgr/libsnapshot/partition_cow_creator_test.cpp
@@ -0,0 +1,90 @@
+// Copyright (C) 2018 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 <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <liblp/builder.h>
+#include <liblp/property_fetcher.h>
+
+#include "partition_cow_creator.h"
+
+using ::android::fs_mgr::MetadataBuilder;
+using ::testing::_;
+using ::testing::AnyNumber;
+using ::testing::Return;
+
+namespace android {
+namespace snapshot {
+
+class MockPropertyFetcher : public fs_mgr::IPropertyFetcher {
+ public:
+ MOCK_METHOD2(GetProperty, std::string(const std::string&, const std::string&));
+ MOCK_METHOD2(GetBoolProperty, bool(const std::string&, bool));
+};
+
+class PartitionCowCreatorTest : ::testing::Test {
+ public:
+ void SetUp() override {
+ fs_mgr::IPropertyFetcher::OverrideForTesting(std::make_unique<MockPropertyFetcher>());
+
+ EXPECT_CALL(fetcher(), GetProperty("ro.boot.slot_suffix", _))
+ .Times(AnyNumber())
+ .WillRepeatedly(Return("_a"));
+ EXPECT_CALL(fetcher(), GetBoolProperty("ro.boot.dynamic_partitions", _))
+ .Times(AnyNumber())
+ .WillRepeatedly(Return(true));
+ EXPECT_CALL(fetcher(), GetBoolProperty("ro.boot.dynamic_partitions_retrofit", _))
+ .Times(AnyNumber())
+ .WillRepeatedly(Return(false));
+ EXPECT_CALL(fetcher(), GetBoolProperty("ro.virtual_ab.enabled", _))
+ .Times(AnyNumber())
+ .WillRepeatedly(Return(true));
+ }
+ void TearDown() override {
+ fs_mgr::IPropertyFetcher::OverrideForTesting(std::make_unique<MockPropertyFetcher>());
+ }
+ MockPropertyFetcher& fetcher() {
+ return *static_cast<MockPropertyFetcher*>(fs_mgr::IPropertyFetcher::GetInstance());
+ }
+};
+
+TEST(PartitionCowCreator, IntersectSelf) {
+ auto builder_a = MetadataBuilder::New(1024 * 1024, 1024, 2);
+ ASSERT_NE(builder_a, nullptr);
+ auto system_a = builder_a->AddPartition("system_a", LP_PARTITION_ATTR_READONLY);
+ ASSERT_NE(system_a, nullptr);
+ ASSERT_TRUE(builder_a->ResizePartition(system_a, 40 * 1024));
+
+ auto builder_b = MetadataBuilder::New(1024 * 1024, 1024, 2);
+ ASSERT_NE(builder_b, nullptr);
+ auto system_b = builder_b->AddPartition("system_b", LP_PARTITION_ATTR_READONLY);
+ ASSERT_NE(system_b, nullptr);
+ ASSERT_TRUE(builder_b->ResizePartition(system_b, 40 * 1024));
+
+ PartitionCowCreator creator{.target_metadata = builder_b.get(),
+ .target_suffix = "_b",
+ .target_partition = system_b,
+ .current_metadata = builder_a.get(),
+ .current_suffix = "_a",
+ .cow_size = 20 * 1024};
+ auto ret = creator.Run();
+ ASSERT_TRUE(ret.has_value());
+ ASSERT_EQ(40 * 1024, ret->snapshot_status.device_size);
+ ASSERT_EQ(40 * 1024, ret->snapshot_status.snapshot_size);
+ ASSERT_EQ(20 * 1024,
+ ret->snapshot_status.cow_file_size + ret->snapshot_status.cow_partition_size);
+}
+
+} // namespace snapshot
+} // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 5813a2d..15d52f1 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -15,6 +15,7 @@
#include <libsnapshot/snapshot.h>
#include <dirent.h>
+#include <math.h>
#include <sys/file.h>
#include <sys/types.h>
#include <sys/unistd.h>
@@ -31,11 +32,13 @@
#include <ext4_utils/ext4_utils.h>
#include <fs_mgr.h>
#include <fs_mgr_dm_linear.h>
+#include <fs_mgr_overlayfs.h>
#include <fstab/fstab.h>
#include <libdm/dm.h>
#include <libfiemap/image_manager.h>
#include <liblp/liblp.h>
+#include "partition_cow_creator.h"
#include "utility.h"
namespace android {
@@ -53,8 +56,10 @@
using android::fs_mgr::CreateDmTable;
using android::fs_mgr::CreateLogicalPartition;
using android::fs_mgr::CreateLogicalPartitionParams;
+using android::fs_mgr::GetPartitionGroupName;
using android::fs_mgr::GetPartitionName;
using android::fs_mgr::LpMetadata;
+using android::fs_mgr::MetadataBuilder;
using android::fs_mgr::SlotNumberForSlotSuffix;
using std::chrono::duration_cast;
using namespace std::chrono_literals;
@@ -73,6 +78,7 @@
std::string GetSuperDevice(uint32_t slot) const override {
return fs_mgr_get_super_partition_name(slot);
}
+ bool IsOverlayfsSetup() const override { return fs_mgr_overlayfs_is_setup(); }
private:
android::fs_mgr::PartitionOpener opener_;
@@ -102,7 +108,7 @@
metadata_dir_ = device_->GetMetadataDir();
}
-[[maybe_unused]] static std::string GetCowName(const std::string& snapshot_name) {
+static std::string GetCowName(const std::string& snapshot_name) {
return snapshot_name + "-cow";
}
@@ -205,7 +211,7 @@
CHECK(lock->lock_mode() == LOCK_EX);
// Sanity check these sizes. Like liblp, we guarantee the partition size
// is respected, which means it has to be sector-aligned. (This guarantee
- // is useful for locating avb footers correctly). The COW size, however,
+ // is useful for locating avb footers correctly). The COW file size, however,
// can be arbitrarily larger than specified, so we can safely round it up.
if (status.device_size % kSectorSize != 0) {
LOG(ERROR) << "Snapshot " << name
@@ -217,10 +223,17 @@
<< status.snapshot_size;
return false;
}
-
- // Round the COW size up to the nearest sector.
- status.cow_file_size += kSectorSize - 1;
- status.cow_file_size &= ~(kSectorSize - 1);
+ if (status.cow_partition_size % kSectorSize != 0) {
+ LOG(ERROR) << "Snapshot " << name
+ << " cow partition size is not a multiple of the sector size: "
+ << status.cow_partition_size;
+ return false;
+ }
+ if (status.cow_file_size % kSectorSize != 0) {
+ LOG(ERROR) << "Snapshot " << name << " cow file size is not a multiple of the sector size: "
+ << status.cow_partition_size;
+ return false;
+ }
status.state = SnapshotState::Created;
status.sectors_allocated = 0;
@@ -253,26 +266,7 @@
std::string cow_image_name = GetCowImageDeviceName(name);
int cow_flags = IImageManager::CREATE_IMAGE_DEFAULT;
- if (!images_->CreateBackingImage(cow_image_name, status.cow_file_size, cow_flags)) {
- return false;
- }
-
- // when the kernel creates a persistent dm-snapshot, it requires a CoW file
- // to store the modifications. The kernel interface does not specify how
- // the CoW is used, and there is no standard associated.
- // By looking at the current implementation, the CoW file is treated as:
- // - a _NEW_ snapshot if its first 32 bits are zero, so the newly created
- // dm-snapshot device will look like a perfect copy of the origin device;
- // - an _EXISTING_ snapshot if the first 32 bits are equal to a
- // kernel-specified magic number and the CoW file metadata is set as valid,
- // so it can be used to resume the last state of a snapshot device;
- // - an _INVALID_ snapshot otherwise.
- // To avoid zero-filling the whole CoW file when a new dm-snapshot is
- // created, here we zero-fill only the first 32 bits. This is a temporary
- // workaround that will be discussed again when the kernel API gets
- // consolidated.
- ssize_t dm_snap_magic_size = 4; // 32 bit
- return images_->ZeroFillNewImage(cow_image_name, dm_snap_magic_size);
+ return images_->CreateBackingImage(cow_image_name, status.cow_file_size, cow_flags);
}
bool SnapshotManager::MapSnapshot(LockedFile* lock, const std::string& name,
@@ -390,21 +384,24 @@
}
bool SnapshotManager::MapCowImage(const std::string& name,
- const std::chrono::milliseconds& timeout_ms,
- std::string* cow_dev) {
+ const std::chrono::milliseconds& timeout_ms) {
if (!EnsureImageManager()) return false;
auto cow_image_name = GetCowImageDeviceName(name);
bool ok;
+ std::string cow_dev;
if (has_local_image_manager_) {
// If we forced a local image manager, it means we don't have binder,
// which means first-stage init. We must use device-mapper.
const auto& opener = device_->GetPartitionOpener();
- ok = images_->MapImageWithDeviceMapper(opener, cow_image_name, cow_dev);
+ ok = images_->MapImageWithDeviceMapper(opener, cow_image_name, &cow_dev);
} else {
- ok = images_->MapImageDevice(cow_image_name, timeout_ms, cow_dev);
+ ok = images_->MapImageDevice(cow_image_name, timeout_ms, &cow_dev);
}
- if (!ok) {
+
+ if (ok) {
+ LOG(INFO) << "Mapped " << cow_image_name << " to " << cow_dev;
+ } else {
LOG(ERROR) << "Could not map image device: " << cow_image_name;
}
return ok;
@@ -413,22 +410,15 @@
bool SnapshotManager::UnmapSnapshot(LockedFile* lock, const std::string& name) {
CHECK(lock);
- SnapshotStatus status;
- if (!ReadSnapshotStatus(lock, name, &status)) {
- return false;
- }
-
auto& dm = DeviceMapper::Instance();
if (!dm.DeleteDeviceIfExists(name)) {
LOG(ERROR) << "Could not delete snapshot device: " << name;
return false;
}
- // There may be an extra device, since the kernel doesn't let us have a
- // snapshot and linear target in the same table.
- auto dm_name = GetSnapshotDeviceName(name, status);
- if (name != dm_name && !dm.DeleteDeviceIfExists(dm_name)) {
- LOG(ERROR) << "Could not delete inner snapshot device: " << dm_name;
+ auto snapshot_extra_device = GetSnapshotExtraDeviceName(name);
+ if (!dm.DeleteDeviceIfExists(snapshot_extra_device)) {
+ LOG(ERROR) << "Could not delete snapshot inner device: " << snapshot_extra_device;
return false;
}
@@ -445,11 +435,12 @@
CHECK(lock->lock_mode() == LOCK_EX);
if (!EnsureImageManager()) return false;
+ if (!UnmapCowDevices(lock, name)) {
+ return false;
+ }
+
auto cow_image_name = GetCowImageDeviceName(name);
if (images_->BackingImageExists(cow_image_name)) {
- if (!images_->UnmapImageIfExists(cow_image_name)) {
- return false;
- }
if (!images_->DeleteBackingImage(cow_image_name)) {
return false;
}
@@ -992,24 +983,16 @@
}
}
- // Grab the partition metadata for the snapshot.
uint32_t slot = SlotNumberForSlotSuffix(device_->GetSlotSuffix());
- auto super_device = device_->GetSuperDevice(slot);
- const auto& opener = device_->GetPartitionOpener();
- auto metadata = android::fs_mgr::ReadMetadata(opener, super_device, slot);
- if (!metadata) {
- LOG(ERROR) << "Could not read super partition metadata.";
- return false;
- }
- auto partition = android::fs_mgr::FindPartition(*metadata.get(), name);
- if (!partition) {
- LOG(ERROR) << "Snapshot does not have a partition in super: " << name;
- return false;
- }
-
// Create a DmTable that is identical to the base device.
+ CreateLogicalPartitionParams base_device_params{
+ .block_device = device_->GetSuperDevice(slot),
+ .metadata_slot = slot,
+ .partition_name = name,
+ .partition_opener = &device_->GetPartitionOpener(),
+ };
DmTable table;
- if (!CreateDmTable(opener, *metadata.get(), *partition, super_device, &table)) {
+ if (!CreateDmTable(base_device_params, &table)) {
LOG(ERROR) << "Could not create a DmTable for partition: " << name;
return false;
}
@@ -1086,7 +1069,7 @@
bool ok = true;
for (const auto& name : snapshots) {
- ok &= DeleteSnapshot(lock, name);
+ ok &= (UnmapPartitionWithSnapshot(lock, name) && DeleteSnapshot(lock, name));
}
return ok;
}
@@ -1188,6 +1171,12 @@
}
for (const auto& partition : metadata->partitions) {
+ if (GetPartitionGroupName(metadata->groups[partition.group_index]) == kCowGroupName) {
+ LOG(INFO) << "Skip mapping partition " << GetPartitionName(partition) << " in group "
+ << kCowGroupName;
+ continue;
+ }
+
CreateLogicalPartitionParams params = {
.block_device = super_device,
.metadata = metadata.get(),
@@ -1229,6 +1218,12 @@
CHECK(lock);
path->clear();
+ if (params.GetPartitionName() != params.GetDeviceName()) {
+ LOG(ERROR) << "Mapping snapshot with a different name is unsupported: partition_name = "
+ << params.GetPartitionName() << ", device_name = " << params.GetDeviceName();
+ return false;
+ }
+
// Fill out fields in CreateLogicalPartitionParams so that we have more information (e.g. by
// reading super partition metadata).
CreateLogicalPartitionParams::OwnedData params_owned_data;
@@ -1304,22 +1299,20 @@
return false;
}
- // If there is a timeout specified, compute the remaining time to call Map* functions.
- // init calls CreateLogicalAndSnapshotPartitions, which has no timeout specified. Still call
- // Map* functions in this case.
auto remaining_time = GetRemainingTime(params.timeout_ms, begin);
if (remaining_time.count() < 0) return false;
- std::string cow_image_device;
- if (!MapCowImage(params.GetPartitionName(), remaining_time, &cow_image_device)) {
- LOG(ERROR) << "Could not map cow image for partition: " << params.GetPartitionName();
+ std::string cow_name;
+ CreateLogicalPartitionParams cow_params = params;
+ cow_params.timeout_ms = remaining_time;
+ if (!MapCowDevices(lock, cow_params, *live_snapshot_status, &created_devices, &cow_name)) {
return false;
}
- created_devices.EmplaceBack<AutoUnmapImage>(images_.get(),
- GetCowImageDeviceName(params.partition_name));
-
- // TODO: map cow linear device here
- std::string cow_device = cow_image_device;
+ std::string cow_device;
+ if (!dm.GetDeviceString(cow_name, &cow_device)) {
+ LOG(ERROR) << "Could not determine major/minor for: " << cow_name;
+ return false;
+ }
remaining_time = GetRemainingTime(params.timeout_ms, begin);
if (remaining_time.count() < 0) return false;
@@ -1338,6 +1331,121 @@
return true;
}
+bool SnapshotManager::UnmapPartitionWithSnapshot(LockedFile* lock,
+ const std::string& target_partition_name) {
+ CHECK(lock);
+
+ if (!UnmapSnapshot(lock, target_partition_name)) {
+ return false;
+ }
+
+ if (!UnmapCowDevices(lock, target_partition_name)) {
+ return false;
+ }
+
+ auto& dm = DeviceMapper::Instance();
+ std::string base_name = GetBaseDeviceName(target_partition_name);
+ if (!dm.DeleteDeviceIfExists(base_name)) {
+ LOG(ERROR) << "Cannot delete base device: " << base_name;
+ return false;
+ }
+
+ LOG(INFO) << "Successfully unmapped snapshot " << target_partition_name;
+
+ return true;
+}
+
+bool SnapshotManager::MapCowDevices(LockedFile* lock, const CreateLogicalPartitionParams& params,
+ const SnapshotStatus& snapshot_status,
+ AutoDeviceList* created_devices, std::string* cow_name) {
+ CHECK(lock);
+ if (!EnsureImageManager()) return false;
+ CHECK(snapshot_status.cow_partition_size + snapshot_status.cow_file_size > 0);
+ auto begin = std::chrono::steady_clock::now();
+
+ std::string partition_name = params.GetPartitionName();
+ std::string cow_image_name = GetCowImageDeviceName(partition_name);
+ *cow_name = GetCowName(partition_name);
+
+ auto& dm = DeviceMapper::Instance();
+
+ // Map COW image if necessary.
+ if (snapshot_status.cow_file_size > 0) {
+ auto remaining_time = GetRemainingTime(params.timeout_ms, begin);
+ if (remaining_time.count() < 0) return false;
+
+ if (!MapCowImage(partition_name, remaining_time)) {
+ LOG(ERROR) << "Could not map cow image for partition: " << partition_name;
+ return false;
+ }
+ created_devices->EmplaceBack<AutoUnmapImage>(images_.get(), cow_image_name);
+
+ // If no COW partition exists, just return the image alone.
+ if (snapshot_status.cow_partition_size == 0) {
+ *cow_name = std::move(cow_image_name);
+ LOG(INFO) << "Mapped COW image for " << partition_name << " at " << *cow_name;
+ return true;
+ }
+ }
+
+ auto remaining_time = GetRemainingTime(params.timeout_ms, begin);
+ if (remaining_time.count() < 0) return false;
+
+ CHECK(snapshot_status.cow_partition_size > 0);
+
+ // Create the DmTable for the COW device. It is the DmTable of the COW partition plus
+ // COW image device as the last extent.
+ CreateLogicalPartitionParams cow_partition_params = params;
+ cow_partition_params.partition = nullptr;
+ cow_partition_params.partition_name = *cow_name;
+ cow_partition_params.device_name.clear();
+ DmTable table;
+ if (!CreateDmTable(cow_partition_params, &table)) {
+ return false;
+ }
+ // If the COW image exists, append it as the last extent.
+ if (snapshot_status.cow_file_size > 0) {
+ std::string cow_image_device;
+ if (!dm.GetDeviceString(cow_image_name, &cow_image_device)) {
+ LOG(ERROR) << "Cannot determine major/minor for: " << cow_image_name;
+ return false;
+ }
+ auto cow_partition_sectors = snapshot_status.cow_partition_size / kSectorSize;
+ auto cow_image_sectors = snapshot_status.cow_file_size / kSectorSize;
+ table.Emplace<DmTargetLinear>(cow_partition_sectors, cow_image_sectors, cow_image_device,
+ 0);
+ }
+
+ // We have created the DmTable now. Map it.
+ std::string cow_path;
+ if (!dm.CreateDevice(*cow_name, table, &cow_path, remaining_time)) {
+ LOG(ERROR) << "Could not create COW device: " << *cow_name;
+ return false;
+ }
+ created_devices->EmplaceBack<AutoUnmapDevice>(&dm, *cow_name);
+ LOG(INFO) << "Mapped COW device for " << params.GetPartitionName() << " at " << cow_path;
+ return true;
+}
+
+bool SnapshotManager::UnmapCowDevices(LockedFile* lock, const std::string& name) {
+ CHECK(lock);
+ if (!EnsureImageManager()) return false;
+
+ auto& dm = DeviceMapper::Instance();
+ auto cow_name = GetCowName(name);
+ if (!dm.DeleteDeviceIfExists(cow_name)) {
+ LOG(ERROR) << "Cannot unmap " << cow_name;
+ return false;
+ }
+
+ std::string cow_image_name = GetCowImageDeviceName(name);
+ if (!images_->UnmapImageIfExists(cow_image_name)) {
+ LOG(ERROR) << "Cannot unmap image " << cow_image_name;
+ return false;
+ }
+ return true;
+}
+
auto SnapshotManager::OpenFile(const std::string& file, int open_flags, int lock_flags)
-> std::unique_ptr<LockedFile> {
unique_fd fd(open(file.c_str(), open_flags | O_CLOEXEC | O_NOFOLLOW | O_SYNC, 0660));
@@ -1605,5 +1713,200 @@
return true;
}
+bool SnapshotManager::CreateUpdateSnapshots(MetadataBuilder* target_metadata,
+ const std::string& target_suffix,
+ MetadataBuilder* current_metadata,
+ const std::string& current_suffix,
+ const std::map<std::string, uint64_t>& cow_sizes) {
+ auto lock = LockExclusive();
+ if (!lock) return false;
+
+ // Add _{target_suffix} to COW size map.
+ std::map<std::string, uint64_t> suffixed_cow_sizes;
+ for (const auto& [name, size] : cow_sizes) {
+ suffixed_cow_sizes[name + target_suffix] = size;
+ }
+
+ target_metadata->RemoveGroupAndPartitions(kCowGroupName);
+ if (!target_metadata->AddGroup(kCowGroupName, 0)) {
+ LOG(ERROR) << "Cannot add group " << kCowGroupName;
+ return false;
+ }
+
+ // TODO(b/134949511): remove this check. Right now, with overlayfs mounted, the scratch
+ // partition takes up a big chunk of space in super, causing COW images to be created on
+ // retrofit Virtual A/B devices.
+ if (device_->IsOverlayfsSetup()) {
+ LOG(ERROR) << "Cannot create update snapshots with overlayfs setup. Run `adb enable-verity`"
+ << ", reboot, then try again.";
+ return false;
+ }
+
+ // Check that all these metadata is not retrofit dynamic partitions. Snapshots on
+ // devices with retrofit dynamic partitions does not make sense.
+ // This ensures that current_metadata->GetFreeRegions() uses the same device
+ // indices as target_metadata (i.e. 0 -> "super").
+ // This is also assumed in MapCowDevices() call below.
+ CHECK(current_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME &&
+ target_metadata->GetBlockDevicePartitionName(0) == LP_METADATA_DEFAULT_PARTITION_NAME);
+
+ std::map<std::string, SnapshotStatus> all_snapshot_status;
+
+ // In case of error, automatically delete devices that are created along the way.
+ // Note that "lock" is destroyed after "created_devices", so it is safe to use |lock| for
+ // these devices.
+ AutoDeviceList created_devices;
+
+ for (auto* target_partition : ListPartitionsWithSuffix(target_metadata, target_suffix)) {
+ std::optional<uint64_t> cow_size = std::nullopt;
+ auto it = suffixed_cow_sizes.find(target_partition->name());
+ if (it != suffixed_cow_sizes.end()) {
+ cow_size = it->second;
+ LOG(INFO) << "Using provided COW size " << *cow_size << " for partition "
+ << target_partition->name();
+ }
+
+ // Compute the device sizes for the partition.
+ PartitionCowCreator cow_creator{target_metadata, target_suffix, target_partition,
+ current_metadata, current_suffix, cow_size};
+ auto cow_creator_ret = cow_creator.Run();
+ if (!cow_creator_ret.has_value()) {
+ return false;
+ }
+
+ LOG(INFO) << "For partition " << target_partition->name()
+ << ", device size = " << cow_creator_ret->snapshot_status.device_size
+ << ", snapshot size = " << cow_creator_ret->snapshot_status.snapshot_size
+ << ", cow partition size = "
+ << cow_creator_ret->snapshot_status.cow_partition_size
+ << ", cow file size = " << cow_creator_ret->snapshot_status.cow_file_size;
+
+ // Delete any existing snapshot before re-creating one.
+ if (!DeleteSnapshot(lock.get(), target_partition->name())) {
+ LOG(ERROR) << "Cannot delete existing snapshot before creating a new one for partition "
+ << target_partition->name();
+ return false;
+ }
+
+ // It is possible that the whole partition uses free space in super, and snapshot / COW
+ // would not be needed. In this case, skip the partition.
+ bool needs_snapshot = cow_creator_ret->snapshot_status.snapshot_size > 0;
+ bool needs_cow = (cow_creator_ret->snapshot_status.cow_partition_size +
+ cow_creator_ret->snapshot_status.cow_file_size) > 0;
+ CHECK(needs_snapshot == needs_cow);
+
+ if (!needs_snapshot) {
+ LOG(INFO) << "Skip creating snapshot for partition " << target_partition->name()
+ << "because nothing needs to be snapshotted.";
+ continue;
+ }
+
+ // Store these device sizes to snapshot status file.
+ if (!CreateSnapshot(lock.get(), target_partition->name(),
+ cow_creator_ret->snapshot_status)) {
+ return false;
+ }
+ created_devices.EmplaceBack<AutoDeleteSnapshot>(this, lock.get(), target_partition->name());
+
+ // Create the COW partition. That is, use any remaining free space in super partition before
+ // creating the COW images.
+ if (cow_creator_ret->snapshot_status.cow_partition_size > 0) {
+ CHECK(cow_creator_ret->snapshot_status.cow_partition_size % kSectorSize == 0)
+ << "cow_partition_size == "
+ << cow_creator_ret->snapshot_status.cow_partition_size
+ << " is not a multiple of sector size " << kSectorSize;
+ auto cow_partition = target_metadata->AddPartition(GetCowName(target_partition->name()),
+ kCowGroupName, 0 /* flags */);
+ if (cow_partition == nullptr) {
+ return false;
+ }
+
+ if (!target_metadata->ResizePartition(
+ cow_partition, cow_creator_ret->snapshot_status.cow_partition_size,
+ cow_creator_ret->cow_partition_usable_regions)) {
+ LOG(ERROR) << "Cannot create COW partition on metadata with size "
+ << cow_creator_ret->snapshot_status.cow_partition_size;
+ return false;
+ }
+ // Only the in-memory target_metadata is modified; nothing to clean up if there is an
+ // error in the future.
+ }
+
+ // Create the backing COW image if necessary.
+ if (cow_creator_ret->snapshot_status.cow_file_size > 0) {
+ if (!CreateCowImage(lock.get(), target_partition->name())) {
+ return false;
+ }
+ }
+
+ all_snapshot_status[target_partition->name()] = std::move(cow_creator_ret->snapshot_status);
+
+ LOG(INFO) << "Successfully created snapshot for " << target_partition->name();
+ }
+
+ auto& dm = DeviceMapper::Instance();
+ auto exported_target_metadata = target_metadata->Export();
+ CreateLogicalPartitionParams cow_params{
+ .block_device = LP_METADATA_DEFAULT_PARTITION_NAME,
+ .metadata = exported_target_metadata.get(),
+ .timeout_ms = std::chrono::milliseconds::max(),
+ .partition_opener = &device_->GetPartitionOpener(),
+ };
+ for (auto* target_partition : ListPartitionsWithSuffix(target_metadata, target_suffix)) {
+ AutoDeviceList created_devices_for_cow;
+
+ if (!UnmapPartitionWithSnapshot(lock.get(), target_partition->name())) {
+ LOG(ERROR) << "Cannot unmap existing COW devices before re-mapping them for zero-fill: "
+ << target_partition->name();
+ return false;
+ }
+
+ auto it = all_snapshot_status.find(target_partition->name());
+ CHECK(it != all_snapshot_status.end()) << target_partition->name();
+ cow_params.partition_name = target_partition->name();
+ std::string cow_name;
+ if (!MapCowDevices(lock.get(), cow_params, it->second, &created_devices_for_cow,
+ &cow_name)) {
+ return false;
+ }
+
+ std::string cow_path;
+ if (!dm.GetDmDevicePathByName(cow_name, &cow_path)) {
+ LOG(ERROR) << "Cannot determine path for " << cow_name;
+ return false;
+ }
+
+ if (!InitializeCow(cow_path)) {
+ LOG(ERROR) << "Can't zero-fill COW device for " << target_partition->name() << ": "
+ << cow_path;
+ return false;
+ }
+ // Let destructor of created_devices_for_cow to unmap the COW devices.
+ };
+
+ created_devices.Release();
+ LOG(INFO) << "Successfully created all snapshots for target slot " << target_suffix;
+
+ return true;
+}
+
+bool SnapshotManager::MapUpdateSnapshot(const CreateLogicalPartitionParams& params,
+ std::string* snapshot_path) {
+ auto lock = LockShared();
+ if (!lock) return false;
+ if (!UnmapPartitionWithSnapshot(lock.get(), params.GetPartitionName())) {
+ LOG(ERROR) << "Cannot unmap existing snapshot before re-mapping it: "
+ << params.GetPartitionName();
+ return false;
+ }
+ return MapPartitionWithSnapshot(lock.get(), params, snapshot_path);
+}
+
+bool SnapshotManager::UnmapUpdateSnapshot(const std::string& target_partition_name) {
+ auto lock = LockShared();
+ if (!lock) return false;
+ return UnmapPartitionWithSnapshot(lock.get(), target_partition_name);
+}
+
} // namespace snapshot
} // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 429fd8e..876b8f8 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -33,7 +33,9 @@
#include <liblp/builder.h>
#include <liblp/mock_property_fetcher.h>
+#include "digital_storage.h"
#include "test_helpers.h"
+#include "utility.h"
namespace android {
namespace snapshot {
@@ -45,10 +47,12 @@
using android::fs_mgr::BlockDeviceInfo;
using android::fs_mgr::CreateLogicalPartitionParams;
using android::fs_mgr::DestroyLogicalPartition;
+using android::fs_mgr::GetPartitionGroupName;
using android::fs_mgr::GetPartitionName;
using android::fs_mgr::MetadataBuilder;
using namespace ::testing;
using namespace android::fs_mgr::testing;
+using namespace android::digital_storage;
using namespace std::chrono_literals;
using namespace std::string_literals;
@@ -58,7 +62,7 @@
TestDeviceInfo* test_device = nullptr;
std::string fake_super;
-static constexpr uint64_t kSuperSize = 16 * 1024 * 1024;
+static constexpr uint64_t kSuperSize = (16_MiB).bytes();
class SnapshotTest : public ::testing::Test {
public:
@@ -105,7 +109,7 @@
std::vector<std::string> snapshots = {"test-snapshot", "test_partition_a",
"test_partition_b"};
for (const auto& snapshot : snapshots) {
- DeleteSnapshotDevice(snapshot);
+ ASSERT_TRUE(DeleteSnapshotDevice(snapshot));
DeleteBackingImage(image_manager_, snapshot + "-cow-img");
auto status_file = sm->GetSnapshotStatusFilePath(snapshot);
@@ -211,15 +215,52 @@
return true;
}
- void DeleteSnapshotDevice(const std::string& snapshot) {
- DeleteDevice(snapshot);
- DeleteDevice(snapshot + "-inner");
- ASSERT_TRUE(image_manager_->UnmapImageIfExists(snapshot + "-cow-img"));
- }
- void DeleteDevice(const std::string& device) {
- if (dm_.GetState(device) != DmDeviceState::INVALID) {
- ASSERT_TRUE(dm_.DeleteDevice(device));
+ AssertionResult DeleteSnapshotDevice(const std::string& snapshot) {
+ AssertionResult res = AssertionSuccess();
+ if (!(res = DeleteDevice(snapshot))) return res;
+ if (!(res = DeleteDevice(snapshot + "-inner"))) return res;
+ if (!(res = DeleteDevice(snapshot + "-cow"))) return res;
+ if (!image_manager_->UnmapImageIfExists(snapshot + "-cow-img")) {
+ return AssertionFailure() << "Cannot unmap image " << snapshot << "-cow-img";
}
+ if (!(res = DeleteDevice(snapshot + "-base"))) return res;
+ return AssertionSuccess();
+ }
+
+ AssertionResult DeleteDevice(const std::string& device) {
+ if (!dm_.DeleteDeviceIfExists(device)) {
+ return AssertionFailure() << "Can't delete " << device;
+ }
+ return AssertionSuccess();
+ }
+
+ AssertionResult CreateCowImage(const std::string& name) {
+ if (!sm->CreateCowImage(lock_.get(), name)) {
+ return AssertionFailure() << "Cannot create COW image " << name;
+ }
+ std::string cow_device;
+ auto map_res = MapCowImage(name, 10s, &cow_device);
+ if (!map_res) {
+ return map_res;
+ }
+ if (!InitializeCow(cow_device)) {
+ return AssertionFailure() << "Cannot zero fill " << cow_device;
+ }
+ if (!sm->UnmapCowImage(name)) {
+ return AssertionFailure() << "Cannot unmap " << name << " after zero filling it";
+ }
+ return AssertionSuccess();
+ }
+
+ AssertionResult MapCowImage(const std::string& name,
+ const std::chrono::milliseconds& timeout_ms, std::string* path) {
+ if (!sm->MapCowImage(name, timeout_ms)) {
+ return AssertionFailure() << "Cannot map cow image " << name;
+ }
+ if (!dm_.GetDmDevicePathByName(name + "-cow-img"s, path)) {
+ return AssertionFailure() << "No path for " << name << "-cow-img";
+ }
+ return AssertionSuccess();
}
DeviceMapper& dm_;
@@ -236,7 +277,7 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+ ASSERT_TRUE(CreateCowImage("test-snapshot"));
std::vector<std::string> snapshots;
ASSERT_TRUE(sm->ListSnapshots(lock_.get(), &snapshots));
@@ -265,13 +306,13 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+ ASSERT_TRUE(CreateCowImage("test-snapshot"));
std::string base_device;
ASSERT_TRUE(CreatePartition("base-device", kDeviceSize, &base_device));
std::string cow_device;
- ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+ ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
std::string snap_device;
ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
@@ -288,13 +329,13 @@
{.device_size = kDeviceSize,
.snapshot_size = kSnapshotSize,
.cow_file_size = kSnapshotSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+ ASSERT_TRUE(CreateCowImage("test-snapshot"));
std::string base_device;
ASSERT_TRUE(CreatePartition("base-device", kDeviceSize, &base_device));
std::string cow_device;
- ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+ ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
std::string snap_device;
ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
@@ -344,8 +385,8 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
- ASSERT_TRUE(sm->MapCowImage("test_partition_b", 10s, &cow_device));
+ ASSERT_TRUE(CreateCowImage("test_partition_b"));
+ ASSERT_TRUE(MapCowImage("test_partition_b", 10s, &cow_device));
ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test_partition_b", base_device, cow_device, 10s,
&snap_device));
@@ -403,11 +444,11 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test-snapshot"));
+ ASSERT_TRUE(CreateCowImage("test-snapshot"));
std::string base_device, cow_device, snap_device;
ASSERT_TRUE(CreatePartition("base-device", kDeviceSize, &base_device));
- ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+ ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
ASSERT_TRUE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
&snap_device));
@@ -433,11 +474,11 @@
// Wait 1s, otherwise DeleteSnapshotDevice may fail with EBUSY.
sleep(1);
// Forcefully delete the snapshot device, so it looks like we just rebooted.
- DeleteSnapshotDevice("test-snapshot");
+ ASSERT_TRUE(DeleteSnapshotDevice("test-snapshot"));
// Map snapshot should fail now, because we're in a merge-complete state.
ASSERT_TRUE(AcquireLock());
- ASSERT_TRUE(sm->MapCowImage("test-snapshot", 10s, &cow_device));
+ ASSERT_TRUE(MapCowImage("test-snapshot", 10s, &cow_device));
ASSERT_FALSE(sm->MapSnapshot(lock_.get(), "test-snapshot", base_device, cow_device, 10s,
&snap_device));
@@ -462,7 +503,7 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
+ ASSERT_TRUE(CreateCowImage("test_partition_b"));
// Simulate a reboot into the new slot.
lock_ = nullptr;
@@ -504,7 +545,7 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
+ ASSERT_TRUE(CreateCowImage("test_partition_b"));
// Simulate a reboot into the new slot.
lock_ = nullptr;
@@ -552,7 +593,7 @@
{.device_size = kDeviceSize,
.snapshot_size = kDeviceSize,
.cow_file_size = kDeviceSize}));
- ASSERT_TRUE(sm->CreateCowImage(lock_.get(), "test_partition_b"));
+ ASSERT_TRUE(CreateCowImage("test_partition_b"));
// Simulate a reboot into the new slot.
lock_ = nullptr;
@@ -570,7 +611,7 @@
// Now, reflash super. Note that we haven't called ProcessUpdateState, so the
// status is still Merging.
- DeleteSnapshotDevice("test_partition_b");
+ ASSERT_TRUE(DeleteSnapshotDevice("test_partition_b"));
ASSERT_TRUE(init->image_manager()->UnmapImageIfExists("test_partition_b-cow-img"));
FormatFakeSuper();
ASSERT_TRUE(CreatePartition("test_partition_b", kDeviceSize));
@@ -583,6 +624,419 @@
ASSERT_EQ(sm->GetUpdateState(), UpdateState::None);
}
+class SnapshotUpdateTest : public SnapshotTest {
+ public:
+ void SetUp() override {
+ SnapshotTest::SetUp();
+ Cleanup();
+
+ // Cleanup() changes slot suffix, so initialize it again.
+ test_device->set_slot_suffix("_a");
+
+ ON_CALL(*GetMockedPropertyFetcher(), GetBoolProperty("ro.virtual_ab.enabled", _))
+ .WillByDefault(Return(true));
+
+ opener = std::make_unique<TestPartitionOpener>(fake_super);
+
+ // Initialize source partition metadata. sys_b is similar to system_other.
+ // Not using full name "system", "vendor", "product" because these names collide with the
+ // mapped partitions on the running device.
+ src = MetadataBuilder::New(*opener, "super", 0);
+ ASSERT_NE(nullptr, src);
+ auto partition = src->AddPartition("sys_a", 0);
+ ASSERT_NE(nullptr, partition);
+ ASSERT_TRUE(src->ResizePartition(partition, 3_MiB));
+ partition = src->AddPartition("vnd_a", 0);
+ ASSERT_NE(nullptr, partition);
+ ASSERT_TRUE(src->ResizePartition(partition, 3_MiB));
+ partition = src->AddPartition("prd_a", 0);
+ ASSERT_NE(nullptr, partition);
+ ASSERT_TRUE(src->ResizePartition(partition, 3_MiB));
+ partition = src->AddPartition("sys_b", 0);
+ ASSERT_NE(nullptr, partition);
+ ASSERT_TRUE(src->ResizePartition(partition, 1_MiB));
+ auto metadata = src->Export();
+ ASSERT_NE(nullptr, metadata);
+ ASSERT_TRUE(UpdatePartitionTable(*opener, "super", *metadata.get(), 0));
+
+ // Map source partitions. Additionally, map sys_b to simulate system_other after flashing.
+ std::string path;
+ for (const auto& name : {"sys_a", "vnd_a", "prd_a", "sys_b"}) {
+ ASSERT_TRUE(CreateLogicalPartition(
+ CreateLogicalPartitionParams{
+ .block_device = fake_super,
+ .metadata_slot = 0,
+ .partition_name = name,
+ .timeout_ms = 1s,
+ .partition_opener = opener.get(),
+ },
+ &path));
+ ASSERT_TRUE(WriteRandomData(path));
+ auto hash = GetHash(path);
+ ASSERT_TRUE(hash.has_value());
+ hashes_[name] = *hash;
+ }
+ }
+ void TearDown() override {
+ Cleanup();
+ SnapshotTest::TearDown();
+ }
+ void Cleanup() {
+ if (!image_manager_) {
+ InitializeState();
+ }
+ for (const auto& suffix : {"_a", "_b"}) {
+ test_device->set_slot_suffix(suffix);
+ EXPECT_TRUE(sm->CancelUpdate()) << suffix;
+ }
+ EXPECT_TRUE(UnmapAll());
+ }
+
+ static AssertionResult ResizePartitions(
+ MetadataBuilder* builder,
+ const std::vector<std::pair<std::string, uint64_t>>& partition_sizes) {
+ for (auto&& [name, size] : partition_sizes) {
+ auto partition = builder->FindPartition(name);
+ if (!partition) {
+ return AssertionFailure() << "Cannot find partition in metadata " << name;
+ }
+ if (!builder->ResizePartition(partition, size)) {
+ return AssertionFailure()
+ << "Cannot resize partition " << name << " to " << size << " bytes";
+ }
+ }
+ return AssertionSuccess();
+ }
+
+ AssertionResult IsPartitionUnchanged(const std::string& name) {
+ std::string path;
+ if (!dm_.GetDmDevicePathByName(name, &path)) {
+ return AssertionFailure() << "Path of " << name << " cannot be determined";
+ }
+ auto hash = GetHash(path);
+ if (!hash.has_value()) {
+ return AssertionFailure() << "Cannot read partition " << name << ": " << path;
+ }
+ if (hashes_[name] != *hash) {
+ return AssertionFailure() << "Content of " << name << " has changed after the merge";
+ }
+ return AssertionSuccess();
+ }
+
+ std::optional<uint64_t> GetSnapshotSize(const std::string& name) {
+ if (!AcquireLock()) {
+ return std::nullopt;
+ }
+ auto local_lock = std::move(lock_);
+
+ SnapshotManager::SnapshotStatus status;
+ if (!sm->ReadSnapshotStatus(local_lock.get(), name, &status)) {
+ return std::nullopt;
+ }
+ return status.snapshot_size;
+ }
+
+ AssertionResult UnmapAll() {
+ for (const auto& name : {"sys", "vnd", "prd"}) {
+ if (!dm_.DeleteDeviceIfExists(name + "_a"s)) {
+ return AssertionFailure() << "Cannot unmap " << name << "_a";
+ }
+ if (!DeleteSnapshotDevice(name + "_b"s)) {
+ return AssertionFailure() << "Cannot delete snapshot " << name << "_b";
+ }
+ }
+ return AssertionSuccess();
+ }
+
+ std::unique_ptr<TestPartitionOpener> opener;
+ std::unique_ptr<MetadataBuilder> src;
+ std::map<std::string, std::string> hashes_;
+};
+
+// Test full update flow executed by update_engine. Some partitions uses super empty space,
+// some uses images, and some uses both.
+// Also test UnmapUpdateSnapshot unmaps everything.
+// Also test first stage mount and merge after this.
+TEST_F(SnapshotUpdateTest, FullUpdateFlow) {
+ // OTA client calls CancelUpdate then BeginUpdate before doing anything.
+ ASSERT_TRUE(sm->CancelUpdate());
+ ASSERT_TRUE(sm->BeginUpdate());
+
+ // OTA client blindly unmaps all partitions that are possibly mapped.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ ASSERT_TRUE(sm->UnmapUpdateSnapshot(name));
+ }
+
+ // OTA client adjusts the partition sizes before giving it to CreateUpdateSnapshots.
+ auto tgt = MetadataBuilder::NewForUpdate(*opener, "super", 0, 1);
+ ASSERT_NE(nullptr, tgt);
+ // clang-format off
+ ASSERT_TRUE(ResizePartitions(tgt.get(), {
+ {"sys_b", 4_MiB}, // grows
+ {"vnd_b", 4_MiB}, // grows
+ {"prd_b", 4_MiB}, // grows
+ }));
+ // clang-format on
+
+ ASSERT_TRUE(sm->CreateUpdateSnapshots(tgt.get(), "_b", src.get(), "_a", {}));
+
+ // Test that partitions prioritize using space in super.
+ ASSERT_NE(nullptr, tgt->FindPartition("sys_b-cow"));
+ ASSERT_NE(nullptr, tgt->FindPartition("vnd_b-cow"));
+ ASSERT_EQ(nullptr, tgt->FindPartition("prd_b-cow"));
+
+ // The metadata slot 1 is now updated.
+ auto metadata = tgt->Export();
+ ASSERT_NE(nullptr, metadata);
+ ASSERT_TRUE(UpdatePartitionTable(*opener, "super", *metadata.get(), 1));
+
+ // Write some data to target partitions.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ std::string path;
+ ASSERT_TRUE(sm->MapUpdateSnapshot(
+ CreateLogicalPartitionParams{
+ .block_device = fake_super,
+ .metadata_slot = 1,
+ .partition_name = name,
+ .timeout_ms = 10s,
+ .partition_opener = opener.get(),
+ },
+ &path))
+ << name;
+ ASSERT_TRUE(WriteRandomData(path));
+ auto hash = GetHash(path);
+ ASSERT_TRUE(hash.has_value());
+ hashes_[name] = *hash;
+ }
+
+ // Assert that source partitions aren't affected.
+ for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name));
+ }
+
+ ASSERT_TRUE(sm->FinishedSnapshotWrites());
+
+ // Simulate shutting down the device.
+ ASSERT_TRUE(UnmapAll());
+
+ // After reboot, init does first stage mount.
+ auto rebooted = new TestDeviceInfo(fake_super);
+ rebooted->set_slot_suffix("_b");
+ auto init = SnapshotManager::NewForFirstStageMount(rebooted);
+ ASSERT_NE(init, nullptr);
+ ASSERT_TRUE(init->NeedSnapshotsInFirstStageMount());
+ ASSERT_TRUE(init->CreateLogicalAndSnapshotPartitions("super"));
+
+ // Check that the target partitions have the same content.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name));
+ }
+
+ // Initiate the merge and wait for it to be completed.
+ ASSERT_TRUE(init->InitiateMerge());
+ ASSERT_EQ(UpdateState::MergeCompleted, init->ProcessUpdateState());
+
+ // Check that the target partitions have the same content after the merge.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name))
+ << "Content of " << name << " changes after the merge";
+ }
+}
+
+// Test that if new system partitions uses empty space in super, that region is not snapshotted.
+TEST_F(SnapshotUpdateTest, DirectWriteEmptySpace) {
+ auto tgt = MetadataBuilder::NewForUpdate(*opener, "super", 0, 1);
+ ASSERT_NE(nullptr, tgt);
+ // clang-format off
+ ASSERT_TRUE(ResizePartitions(tgt.get(), {
+ {"sys_b", 4_MiB}, // grows
+ // vnd_b and prd_b are unchanged
+ }));
+ // clang-format on
+ ASSERT_TRUE(sm->CreateUpdateSnapshots(tgt.get(), "_b", src.get(), "_a", {}));
+
+ ASSERT_EQ(3_MiB, GetSnapshotSize("sys_b").value_or(0));
+}
+
+// Test that if new system partitions uses space of old vendor partition, that region is
+// snapshotted.
+TEST_F(SnapshotUpdateTest, SnapshotOldPartitions) {
+ auto tgt = MetadataBuilder::NewForUpdate(*opener, "super", 0, 1);
+ ASSERT_NE(nullptr, tgt);
+ // clang-format off
+ ASSERT_TRUE(ResizePartitions(tgt.get(), {
+ {"vnd_b", 2_MiB}, // shrinks
+ {"sys_b", 4_MiB}, // grows
+ // prd_b is unchanged
+ }));
+ // clang-format on
+ ASSERT_TRUE(sm->CreateUpdateSnapshots(tgt.get(), "_b", src.get(), "_a", {}));
+
+ ASSERT_EQ(4_MiB, GetSnapshotSize("sys_b").value_or(0));
+}
+
+// Test that even if there seem to be empty space in target metadata, COW partition won't take
+// it because they are used by old partitions.
+TEST_F(SnapshotUpdateTest, CowPartitionDoNotTakeOldPartitions) {
+ auto tgt = MetadataBuilder::NewForUpdate(*opener, "super", 0, 1);
+ ASSERT_NE(nullptr, tgt);
+ // clang-format off
+ ASSERT_TRUE(ResizePartitions(tgt.get(), {
+ {"sys_b", 2_MiB}, // shrinks
+ // vnd_b and prd_b are unchanged
+ }));
+ // clang-format on
+ ASSERT_TRUE(sm->CreateUpdateSnapshots(tgt.get(), "_b", src.get(), "_a", {}));
+
+ auto metadata = tgt->Export();
+ ASSERT_NE(nullptr, metadata);
+ std::vector<std::string> written;
+ // Write random data to all COW partitions in super
+ for (auto p : metadata->partitions) {
+ if (GetPartitionGroupName(metadata->groups[p.group_index]) != kCowGroupName) {
+ continue;
+ }
+ std::string path;
+ ASSERT_TRUE(CreateLogicalPartition(
+ CreateLogicalPartitionParams{
+ .block_device = fake_super,
+ .metadata = metadata.get(),
+ .partition = &p,
+ .timeout_ms = 1s,
+ .partition_opener = opener.get(),
+ },
+ &path));
+ ASSERT_TRUE(WriteRandomData(path));
+ written.push_back(GetPartitionName(p));
+ }
+ ASSERT_FALSE(written.empty())
+ << "No COW partitions are created even if there are empty space in super partition";
+
+ // Make sure source partitions aren't affected.
+ for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name));
+ }
+}
+
+// Test that it crashes after creating snapshot status file but before creating COW image, then
+// calling CreateUpdateSnapshots again works.
+TEST_F(SnapshotUpdateTest, SnapshotStatusFileWithoutCow) {
+ // Write some trash snapshot files to simulate leftovers from previous runs.
+ {
+ ASSERT_TRUE(AcquireLock());
+ auto local_lock = std::move(lock_);
+ ASSERT_TRUE(sm->WriteSnapshotStatus(local_lock.get(), "sys_b",
+ SnapshotManager::SnapshotStatus{}));
+ ASSERT_TRUE(image_manager_->CreateBackingImage("sys_b-cow-img", 1_MiB,
+ IImageManager::CREATE_IMAGE_DEFAULT));
+ }
+
+ // Redo the update.
+ ASSERT_TRUE(sm->BeginUpdate());
+ ASSERT_TRUE(sm->UnmapUpdateSnapshot("sys_b"));
+ auto tgt = MetadataBuilder::NewForUpdate(*opener, "super", 0, 1);
+ ASSERT_NE(nullptr, tgt);
+ ASSERT_TRUE(sm->CreateUpdateSnapshots(tgt.get(), "_b", src.get(), "_a", {}));
+
+ // The metadata slot 1 is now updated.
+ auto metadata = tgt->Export();
+ ASSERT_NE(nullptr, metadata);
+ ASSERT_TRUE(UpdatePartitionTable(*opener, "super", *metadata.get(), 1));
+
+ // Check that target partitions can be mapped.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ std::string path;
+ EXPECT_TRUE(sm->MapUpdateSnapshot(
+ CreateLogicalPartitionParams{
+ .block_device = fake_super,
+ .metadata_slot = 1,
+ .partition_name = name,
+ .timeout_ms = 10s,
+ .partition_opener = opener.get(),
+ },
+ &path))
+ << name;
+ }
+}
+
+// Test that the old partitions are not modified.
+TEST_F(SnapshotUpdateTest, TestRollback) {
+ // Execute the update.
+ ASSERT_TRUE(sm->BeginUpdate());
+ ASSERT_TRUE(sm->UnmapUpdateSnapshot("sys_b"));
+ auto tgt = MetadataBuilder::NewForUpdate(*opener, "super", 0, 1);
+ ASSERT_NE(nullptr, tgt);
+ ASSERT_TRUE(sm->CreateUpdateSnapshots(tgt.get(), "_b", src.get(), "_a", {}));
+
+ // The metadata slot 1 is now updated.
+ auto metadata = tgt->Export();
+ ASSERT_NE(nullptr, metadata);
+ ASSERT_TRUE(UpdatePartitionTable(*opener, "super", *metadata.get(), 1));
+
+ // Write some data to target partitions.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ std::string path;
+ ASSERT_TRUE(sm->MapUpdateSnapshot(
+ CreateLogicalPartitionParams{
+ .block_device = fake_super,
+ .metadata_slot = 1,
+ .partition_name = name,
+ .timeout_ms = 10s,
+ .partition_opener = opener.get(),
+ },
+ &path))
+ << name;
+ ASSERT_TRUE(WriteRandomData(path));
+ auto hash = GetHash(path);
+ ASSERT_TRUE(hash.has_value());
+ hashes_[name] = *hash;
+ }
+
+ // Assert that source partitions aren't affected.
+ for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name));
+ }
+
+ ASSERT_TRUE(sm->FinishedSnapshotWrites());
+
+ // Simulate shutting down the device.
+ ASSERT_TRUE(UnmapAll());
+
+ // After reboot, init does first stage mount.
+ auto rebooted = new TestDeviceInfo(fake_super);
+ rebooted->set_slot_suffix("_b");
+ auto init = SnapshotManager::NewForFirstStageMount(rebooted);
+ ASSERT_NE(init, nullptr);
+ ASSERT_TRUE(init->NeedSnapshotsInFirstStageMount());
+ ASSERT_TRUE(init->CreateLogicalAndSnapshotPartitions("super"));
+
+ // Check that the target partitions have the same content.
+ for (const auto& name : {"sys_b", "vnd_b", "prd_b"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name));
+ }
+
+ // Simulate shutting down the device again.
+ ASSERT_TRUE(UnmapAll());
+ rebooted = new TestDeviceInfo(fake_super);
+ rebooted->set_slot_suffix("_a");
+ init = SnapshotManager::NewForFirstStageMount(rebooted);
+ ASSERT_NE(init, nullptr);
+ ASSERT_FALSE(init->NeedSnapshotsInFirstStageMount());
+ ASSERT_TRUE(init->CreateLogicalAndSnapshotPartitions("super"));
+
+ // Assert that the source partitions aren't affected.
+ for (const auto& name : {"sys_a", "vnd_a", "prd_a"}) {
+ ASSERT_TRUE(IsPartitionUnchanged(name));
+ }
+}
+
+// Test that if an update is applied but not booted into, it can be canceled.
+TEST_F(SnapshotUpdateTest, CancelAfterApply) {
+ ASSERT_TRUE(sm->BeginUpdate());
+ ASSERT_TRUE(sm->FinishedSnapshotWrites());
+ ASSERT_TRUE(sm->CancelUpdate());
+}
+
} // namespace snapshot
} // namespace android
@@ -624,6 +1078,7 @@
}
// Clean up previous run.
+ SnapshotUpdateTest().Cleanup();
SnapshotTest().Cleanup();
// Use a separate image manager for our fake super partition.
diff --git a/fs_mgr/libsnapshot/test_helpers.cpp b/fs_mgr/libsnapshot/test_helpers.cpp
index f67dd21..e12ec77 100644
--- a/fs_mgr/libsnapshot/test_helpers.cpp
+++ b/fs_mgr/libsnapshot/test_helpers.cpp
@@ -14,11 +14,18 @@
#include "test_helpers.h"
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
#include <gtest/gtest.h>
+#include <openssl/sha.h>
namespace android {
namespace snapshot {
+using android::base::ReadFully;
+using android::base::unique_fd;
+using android::base::WriteFully;
using android::fiemap::IImageManager;
void DeleteBackingImage(IImageManager* manager, const std::string& name) {
@@ -53,5 +60,55 @@
return PartitionOpener::GetDeviceString(partition_name);
}
+bool WriteRandomData(const std::string& path) {
+ unique_fd rand(open("/dev/urandom", O_RDONLY));
+ unique_fd fd(open(path.c_str(), O_WRONLY));
+
+ char buf[4096];
+ while (true) {
+ ssize_t n = TEMP_FAILURE_RETRY(read(rand.get(), buf, sizeof(buf)));
+ if (n <= 0) return false;
+ if (!WriteFully(fd.get(), buf, n)) {
+ if (errno == ENOSPC) {
+ return true;
+ }
+ PLOG(ERROR) << "Cannot write " << path;
+ return false;
+ }
+ }
+}
+
+std::string ToHexString(const uint8_t* buf, size_t len) {
+ char lookup[] = "0123456789abcdef";
+ std::string out(len * 2 + 1, '\0');
+ char* outp = out.data();
+ for (; len > 0; len--, buf++) {
+ *outp++ = (char)lookup[*buf >> 4];
+ *outp++ = (char)lookup[*buf & 0xf];
+ }
+ return out;
+}
+
+std::optional<std::string> GetHash(const std::string& path) {
+ unique_fd fd(open(path.c_str(), O_RDONLY));
+ char buf[4096];
+ SHA256_CTX ctx;
+ SHA256_Init(&ctx);
+ while (true) {
+ ssize_t n = TEMP_FAILURE_RETRY(read(fd.get(), buf, sizeof(buf)));
+ if (n < 0) {
+ PLOG(ERROR) << "Cannot read " << path;
+ return std::nullopt;
+ }
+ if (n == 0) {
+ break;
+ }
+ SHA256_Update(&ctx, buf, n);
+ }
+ uint8_t out[32];
+ SHA256_Final(out, &ctx);
+ return ToHexString(out, sizeof(out));
+}
+
} // namespace snapshot
} // namespace android
diff --git a/fs_mgr/libsnapshot/test_helpers.h b/fs_mgr/libsnapshot/test_helpers.h
index 9f582d9..d917e35 100644
--- a/fs_mgr/libsnapshot/test_helpers.h
+++ b/fs_mgr/libsnapshot/test_helpers.h
@@ -14,6 +14,7 @@
#pragma once
+#include <optional>
#include <string>
#include <libfiemap/image_manager.h>
@@ -51,6 +52,7 @@
const android::fs_mgr::IPartitionOpener& GetPartitionOpener() const override {
return *opener_.get();
}
+ bool IsOverlayfsSetup() const override { return false; }
void set_slot_suffix(const std::string& suffix) { slot_suffix_ = suffix; }
void set_fake_super(const std::string& path) {
@@ -65,5 +67,10 @@
// Helper for error-spam-free cleanup.
void DeleteBackingImage(android::fiemap::IImageManager* manager, const std::string& name);
+// Write some random data to the given device. Will write until reaching end of the device.
+bool WriteRandomData(const std::string& device);
+
+std::optional<std::string> GetHash(const std::string& path);
+
} // namespace snapshot
} // namespace android
diff --git a/fs_mgr/libsnapshot/utility.cpp b/fs_mgr/libsnapshot/utility.cpp
index 164b472..66629e8 100644
--- a/fs_mgr/libsnapshot/utility.cpp
+++ b/fs_mgr/libsnapshot/utility.cpp
@@ -14,9 +14,13 @@
#include "utility.h"
+#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/strings.h>
+using android::fs_mgr::MetadataBuilder;
+using android::fs_mgr::Partition;
+
namespace android {
namespace snapshot {
@@ -52,5 +56,58 @@
}
}
+std::vector<Partition*> ListPartitionsWithSuffix(MetadataBuilder* builder,
+ const std::string& suffix) {
+ std::vector<Partition*> ret;
+ for (const auto& group : builder->ListGroups()) {
+ for (auto* partition : builder->ListPartitionsInGroup(group)) {
+ if (!base::EndsWith(partition->name(), suffix)) {
+ continue;
+ }
+ ret.push_back(partition);
+ }
+ }
+ return ret;
+}
+
+AutoDeleteSnapshot::~AutoDeleteSnapshot() {
+ if (!name_.empty() && !manager_->DeleteSnapshot(lock_, name_)) {
+ LOG(ERROR) << "Failed to auto delete snapshot " << name_;
+ }
+}
+
+bool InitializeCow(const std::string& device) {
+ // When the kernel creates a persistent dm-snapshot, it requires a CoW file
+ // to store the modifications. The kernel interface does not specify how
+ // the CoW is used, and there is no standard associated.
+ // By looking at the current implementation, the CoW file is treated as:
+ // - a _NEW_ snapshot if its first 32 bits are zero, so the newly created
+ // dm-snapshot device will look like a perfect copy of the origin device;
+ // - an _EXISTING_ snapshot if the first 32 bits are equal to a
+ // kernel-specified magic number and the CoW file metadata is set as valid,
+ // so it can be used to resume the last state of a snapshot device;
+ // - an _INVALID_ snapshot otherwise.
+ // To avoid zero-filling the whole CoW file when a new dm-snapshot is
+ // created, here we zero-fill only the first 32 bits. This is a temporary
+ // workaround that will be discussed again when the kernel API gets
+ // consolidated.
+ // TODO(b/139202197): Remove this hack once the kernel API is consolidated.
+ constexpr ssize_t kDmSnapZeroFillSize = 4; // 32-bit
+
+ char zeros[kDmSnapZeroFillSize] = {0};
+ android::base::unique_fd fd(open(device.c_str(), O_WRONLY | O_BINARY));
+ if (fd < 0) {
+ PLOG(ERROR) << "Can't open COW device: " << device;
+ return false;
+ }
+
+ LOG(INFO) << "Zero-filling COW device: " << device;
+ if (!android::base::WriteFully(fd, zeros, kDmSnapZeroFillSize)) {
+ PLOG(ERROR) << "Can't zero-fill COW device for " << device;
+ return false;
+ }
+ return true;
+}
+
} // namespace snapshot
} // namespace android
diff --git a/fs_mgr/libsnapshot/utility.h b/fs_mgr/libsnapshot/utility.h
index cbab472..a700c46 100644
--- a/fs_mgr/libsnapshot/utility.h
+++ b/fs_mgr/libsnapshot/utility.h
@@ -14,11 +14,14 @@
#pragma once
+#include <functional>
#include <string>
#include <android-base/macros.h>
#include <libdm/dm.h>
#include <libfiemap/image_manager.h>
+#include <liblp/builder.h>
+#include <libsnapshot/snapshot.h>
namespace android {
namespace snapshot {
@@ -81,5 +84,27 @@
android::fiemap::IImageManager* images_ = nullptr;
};
+// Automatically deletes a snapshot. |name| should be the name of the partition, e.g. "system_a".
+// Client is responsible for maintaining the lifetime of |manager| and |lock|.
+struct AutoDeleteSnapshot : AutoDevice {
+ AutoDeleteSnapshot(SnapshotManager* manager, SnapshotManager::LockedFile* lock,
+ const std::string& name)
+ : AutoDevice(name), manager_(manager), lock_(lock) {}
+ AutoDeleteSnapshot(AutoDeleteSnapshot&& other);
+ ~AutoDeleteSnapshot();
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(AutoDeleteSnapshot);
+ SnapshotManager* manager_ = nullptr;
+ SnapshotManager::LockedFile* lock_ = nullptr;
+};
+
+// Return a list of partitions in |builder| with the name ending in |suffix|.
+std::vector<android::fs_mgr::Partition*> ListPartitionsWithSuffix(
+ android::fs_mgr::MetadataBuilder* builder, const std::string& suffix);
+
+// Initialize a device before using it as the COW device for a dm-snapshot device.
+bool InitializeCow(const std::string& device);
+
} // namespace snapshot
} // namespace android