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-rw-r--r--fs_mgr/libsnapshot/include/libsnapshot/mock_snapshot.h4
-rw-r--r--fs_mgr/libsnapshot/include/libsnapshot/snapshot.h26
-rw-r--r--fs_mgr/libsnapshot/include/libsnapshot/snapshot_stub.h3
-rw-r--r--fs_mgr/libsnapshot/include/libsnapshot/snapshot_writer.h9
-rw-r--r--fs_mgr/libsnapshot/snapshot.cpp32
-rw-r--r--fs_mgr/libsnapshot/snapshot_stub.cpp2
-rw-r--r--fs_mgr/libsnapshot/snapshot_test.cpp2
-rw-r--r--fs_mgr/libsnapshot/snapshot_writer.cpp28
8 files changed, 73 insertions, 33 deletions
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/mock_snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/mock_snapshot.h
index 13f19aa87..6dee3d43d 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/mock_snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/mock_snapshot.h
@@ -39,7 +39,9 @@ class MockSnapshotManager : public ISnapshotManager {
std::string* snapshot_path),
(override));
MOCK_METHOD(std::unique_ptr<ISnapshotWriter>, OpenSnapshotWriter,
- (const android::fs_mgr::CreateLogicalPartitionParams& params), (override));
+ (const android::fs_mgr::CreateLogicalPartitionParams& params,
+ const std::optional<std::string>&),
+ (override));
MOCK_METHOD(bool, UnmapUpdateSnapshot, (const std::string& target_partition_name), (override));
MOCK_METHOD(bool, NeedSnapshotsInFirstStageMount, (), (override));
MOCK_METHOD(bool, CreateLogicalAndSnapshotPartitions,
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index 403e350f7..4bbdca3c6 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -182,9 +182,12 @@ class ISnapshotManager {
std::string* snapshot_path) = 0;
// Create an ISnapshotWriter to build a snapshot against a target partition. The partition name
- // must be suffixed.
+ // must be suffixed. If a source partition exists, it must be specified as well. The source
+ // partition will only be used if raw bytes are needed. The source partition should be an
+ // absolute path to the device, not a partition name.
virtual std::unique_ptr<ISnapshotWriter> OpenSnapshotWriter(
- const android::fs_mgr::CreateLogicalPartitionParams& params) = 0;
+ const android::fs_mgr::CreateLogicalPartitionParams& params,
+ const std::optional<std::string>& source_device) = 0;
// Unmap a snapshot device or CowWriter that was previously opened with MapUpdateSnapshot,
// OpenSnapshotWriter. All outstanding open descriptors, writers, or
@@ -300,7 +303,8 @@ class SnapshotManager final : public ISnapshotManager {
bool MapUpdateSnapshot(const CreateLogicalPartitionParams& params,
std::string* snapshot_path) override;
std::unique_ptr<ISnapshotWriter> OpenSnapshotWriter(
- const android::fs_mgr::CreateLogicalPartitionParams& params) override;
+ const android::fs_mgr::CreateLogicalPartitionParams& params,
+ const std::optional<std::string>& source_device) override;
bool UnmapUpdateSnapshot(const std::string& target_partition_name) override;
bool NeedSnapshotsInFirstStageMount() override;
bool CreateLogicalAndSnapshotPartitions(
@@ -540,14 +544,14 @@ class SnapshotManager final : public ISnapshotManager {
};
// Helpers for OpenSnapshotWriter.
- std::unique_ptr<ISnapshotWriter> OpenCompressedSnapshotWriter(LockedFile* lock,
- const std::string& partition_name,
- const SnapshotStatus& status,
- const SnapshotPaths& paths);
- std::unique_ptr<ISnapshotWriter> OpenKernelSnapshotWriter(LockedFile* lock,
- const std::string& partition_name,
- const SnapshotStatus& status,
- const SnapshotPaths& paths);
+ std::unique_ptr<ISnapshotWriter> OpenCompressedSnapshotWriter(
+ LockedFile* lock, const std::optional<std::string>& source_device,
+ const std::string& partition_name, const SnapshotStatus& status,
+ const SnapshotPaths& paths);
+ std::unique_ptr<ISnapshotWriter> OpenKernelSnapshotWriter(
+ LockedFile* lock, const std::optional<std::string>& source_device,
+ const std::string& partition_name, const SnapshotStatus& status,
+ const SnapshotPaths& paths);
// Map the base device, COW devices, and snapshot device.
bool MapPartitionWithSnapshot(LockedFile* lock, CreateLogicalPartitionParams params,
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stub.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stub.h
index cda2bee33..ed790a0f9 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stub.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stub.h
@@ -37,7 +37,8 @@ class SnapshotManagerStub : public ISnapshotManager {
bool MapUpdateSnapshot(const android::fs_mgr::CreateLogicalPartitionParams& params,
std::string* snapshot_path) override;
std::unique_ptr<ISnapshotWriter> OpenSnapshotWriter(
- const android::fs_mgr::CreateLogicalPartitionParams& params) override;
+ const android::fs_mgr::CreateLogicalPartitionParams& params,
+ const std::optional<std::string>& source_device) override;
bool UnmapUpdateSnapshot(const std::string& target_partition_name) override;
bool NeedSnapshotsInFirstStageMount() override;
bool CreateLogicalAndSnapshotPartitions(
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot_writer.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot_writer.h
index da058f910..e25ec07bd 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot_writer.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot_writer.h
@@ -33,13 +33,18 @@ class ISnapshotWriter : public ICowWriter {
// Set the source device. This is used for AddCopy() operations, if the
// underlying writer needs the original bytes (for example if backed by
- // dm-snapshot or if writing directly to an unsnapshotted region).
- void SetSourceDevice(android::base::unique_fd&& source_fd);
+ // dm-snapshot or if writing directly to an unsnapshotted region). The
+ // device is only opened on the first operation that requires it.
+ void SetSourceDevice(const std::string& source_device);
virtual std::unique_ptr<FileDescriptor> OpenReader() = 0;
protected:
+ android::base::borrowed_fd GetSourceFd();
+
+ private:
android::base::unique_fd source_fd_;
+ std::optional<std::string> source_device_;
};
// Send writes to a COW or a raw device directly, based on a threshold.
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 3541ef638..6574457db 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -2471,9 +2471,11 @@ bool SnapshotManager::MapUpdateSnapshot(const CreateLogicalPartitionParams& para
}
std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenSnapshotWriter(
- const android::fs_mgr::CreateLogicalPartitionParams& params) {
+ const android::fs_mgr::CreateLogicalPartitionParams& params,
+ const std::optional<std::string>& source_device) {
#if defined(LIBSNAPSHOT_NO_COW_WRITE)
(void)params;
+ (void)source_device;
LOG(ERROR) << "Snapshots cannot be written in first-stage init or recovery";
return nullptr;
@@ -2508,16 +2510,19 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenSnapshotWriter(
}
if (IsCompressionEnabled()) {
- return OpenCompressedSnapshotWriter(lock.get(), params.GetPartitionName(), status, paths);
+ return OpenCompressedSnapshotWriter(lock.get(), source_device, params.GetPartitionName(),
+ status, paths);
}
- return OpenKernelSnapshotWriter(lock.get(), params.GetPartitionName(), status, paths);
+ return OpenKernelSnapshotWriter(lock.get(), source_device, params.GetPartitionName(), status,
+ paths);
#endif
}
#if !defined(LIBSNAPSHOT_NO_COW_WRITE)
std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenCompressedSnapshotWriter(
- LockedFile* lock, [[maybe_unused]] const std::string& partition_name,
- const SnapshotStatus& status, const SnapshotPaths& paths) {
+ LockedFile* lock, const std::optional<std::string>& source_device,
+ [[maybe_unused]] const std::string& partition_name, const SnapshotStatus& status,
+ const SnapshotPaths& paths) {
CHECK(lock);
CowOptions cow_options;
@@ -2529,13 +2534,9 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenCompressedSnapshotWriter(
CHECK(status.snapshot_size() == status.device_size());
auto writer = std::make_unique<CompressedSnapshotWriter>(cow_options);
-
- unique_fd base_fd(open(paths.target_device.c_str(), O_RDWR | O_CLOEXEC));
- if (base_fd < 0) {
- PLOG(ERROR) << "OpenCompressedSnapshotWriter: open " << paths.target_device;
- return nullptr;
+ if (source_device) {
+ writer->SetSourceDevice(*source_device);
}
- writer->SetSourceDevice(std::move(base_fd));
std::string cow_path;
if (!GetMappedImageDevicePath(paths.cow_device_name, &cow_path)) {
@@ -2557,8 +2558,9 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenCompressedSnapshotWriter(
}
std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenKernelSnapshotWriter(
- LockedFile* lock, [[maybe_unused]] const std::string& partition_name,
- const SnapshotStatus& status, const SnapshotPaths& paths) {
+ LockedFile* lock, const std::optional<std::string>& source_device,
+ [[maybe_unused]] const std::string& partition_name, const SnapshotStatus& status,
+ const SnapshotPaths& paths) {
CHECK(lock);
CowOptions cow_options;
@@ -2573,6 +2575,10 @@ std::unique_ptr<ISnapshotWriter> SnapshotManager::OpenKernelSnapshotWriter(
return nullptr;
}
+ if (source_device) {
+ writer->SetSourceDevice(*source_device);
+ }
+
uint64_t cow_size = status.cow_partition_size() + status.cow_file_size();
writer->SetSnapshotDevice(std::move(fd), cow_size);
diff --git a/fs_mgr/libsnapshot/snapshot_stub.cpp b/fs_mgr/libsnapshot/snapshot_stub.cpp
index 41f5da4a8..5be3c10c8 100644
--- a/fs_mgr/libsnapshot/snapshot_stub.cpp
+++ b/fs_mgr/libsnapshot/snapshot_stub.cpp
@@ -131,7 +131,7 @@ ISnapshotMergeStats* SnapshotManagerStub::GetSnapshotMergeStatsInstance() {
}
std::unique_ptr<ISnapshotWriter> SnapshotManagerStub::OpenSnapshotWriter(
- const CreateLogicalPartitionParams&) {
+ const CreateLogicalPartitionParams&, const std::optional<std::string>&) {
LOG(ERROR) << __FUNCTION__ << " should never be called.";
return nullptr;
}
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 77226adca..732762961 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -903,7 +903,7 @@ class SnapshotUpdateTest : public SnapshotTest {
.partition_opener = opener_.get(),
};
- auto result = sm->OpenSnapshotWriter(params);
+ auto result = sm->OpenSnapshotWriter(params, {});
if (!result) {
return AssertionFailure() << "Cannot open snapshot for writing: " << name;
}
diff --git a/fs_mgr/libsnapshot/snapshot_writer.cpp b/fs_mgr/libsnapshot/snapshot_writer.cpp
index aa49ab1af..19aa80ef6 100644
--- a/fs_mgr/libsnapshot/snapshot_writer.cpp
+++ b/fs_mgr/libsnapshot/snapshot_writer.cpp
@@ -24,13 +24,30 @@
namespace android {
namespace snapshot {
+using android::base::borrowed_fd;
using android::base::unique_fd;
using chromeos_update_engine::FileDescriptor;
ISnapshotWriter::ISnapshotWriter(const CowOptions& options) : ICowWriter(options) {}
-void ISnapshotWriter::SetSourceDevice(android::base::unique_fd&& source_fd) {
- source_fd_ = std::move(source_fd);
+void ISnapshotWriter::SetSourceDevice(const std::string& source_device) {
+ source_device_ = {source_device};
+}
+
+borrowed_fd ISnapshotWriter::GetSourceFd() {
+ if (!source_device_) {
+ LOG(ERROR) << "Attempted to read from source device but none was set";
+ return borrowed_fd{-1};
+ }
+
+ if (source_fd_ < 0) {
+ source_fd_.reset(open(source_device_->c_str(), O_RDONLY | O_CLOEXEC));
+ if (source_fd_ < 0) {
+ PLOG(ERROR) << "open " << *source_device_;
+ return borrowed_fd{-1};
+ }
+ }
+ return source_fd_;
}
CompressedSnapshotWriter::CompressedSnapshotWriter(const CowOptions& options)
@@ -109,9 +126,14 @@ bool OnlineKernelSnapshotWriter::EmitZeroBlocks(uint64_t new_block_start, uint64
}
bool OnlineKernelSnapshotWriter::EmitCopy(uint64_t new_block, uint64_t old_block) {
+ auto source_fd = GetSourceFd();
+ if (source_fd < 0) {
+ return false;
+ }
+
std::string buffer(options_.block_size, 0);
uint64_t offset = old_block * options_.block_size;
- if (!android::base::ReadFullyAtOffset(source_fd_, buffer.data(), buffer.size(), offset)) {
+ if (!android::base::ReadFullyAtOffset(source_fd, buffer.data(), buffer.size(), offset)) {
PLOG(ERROR) << "EmitCopy read";
return false;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-17 23:15:28 +0000