libsnapshot: Export COW image size
Enable libsnapshot to export the size of the COW image, representing the
fraction of the COW device that is temporarily created in the /data
partition, computed just before initializing a merge operation.
Thise additional information can be used by other components (i.e.,
update engine) to enrich Virtual A/B metrics.
Bug: 154016862
Test: manual OTA
Signed-off-by: Alessio Balsini <balsini@google.com>
Signed-off-by: Yifan Hong <elsk@google.com>
Change-Id: I4faa0785f23884e26161e0d51268dd7a305d86bf
Merged-In: I4faa0785f23884e26161e0d51268dd7a305d86bf
(cherry picked from commit 2a1778d3400a10538653f2d60e5f8b87cc4dd2c0)
diff --git a/fs_mgr/libsnapshot/android/snapshot/snapshot.proto b/fs_mgr/libsnapshot/android/snapshot/snapshot.proto
index 2ac0c44..587089e 100644
--- a/fs_mgr/libsnapshot/android/snapshot/snapshot.proto
+++ b/fs_mgr/libsnapshot/android/snapshot/snapshot.proto
@@ -140,4 +140,7 @@
// Number of reboots that occurred after issuing and before completeing the
// merge of all the snapshot devices.
int32 resume_count = 2;
+
+ // Total size of all the COW images before the update.
+ uint64 cow_file_size = 4;
}
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index ac8a25e..b207978 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -148,7 +148,7 @@
// Initiate a merge on all snapshot devices. This should only be used after an
// update has been marked successful after booting.
- bool InitiateMerge();
+ bool InitiateMerge(uint64_t* cow_file_size = nullptr);
// Perform any necessary post-boot actions. This should be run soon after
// /data is mounted.
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stats.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stats.h
index 91dd34f..bdc3ea3 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stats.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot_stats.h
@@ -31,6 +31,8 @@
// Called when merge starts or resumes.
bool Start();
void set_state(android::snapshot::UpdateState state);
+ virtual void set_cow_file_size(uint64_t cow_file_size);
+ virtual uint64_t cow_file_size();
// Called when merge ends. Properly clean up permanent storage.
class Result {
@@ -43,6 +45,8 @@
std::unique_ptr<Result> Finish();
private:
+ virtual ~SnapshotMergeStats() {}
+
bool ReadState();
bool WriteState();
bool DeleteState();
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index d4a3f62..0739fab 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -555,7 +555,7 @@
return true;
}
-bool SnapshotManager::InitiateMerge() {
+bool SnapshotManager::InitiateMerge(uint64_t* cow_file_size) {
auto lock = LockExclusive();
if (!lock) return false;
@@ -618,6 +618,7 @@
}
}
+ uint64_t total_cow_file_size = 0;
DmTargetSnapshot::Status initial_target_values = {};
for (const auto& snapshot : snapshots) {
DmTargetSnapshot::Status current_status;
@@ -627,6 +628,16 @@
initial_target_values.sectors_allocated += current_status.sectors_allocated;
initial_target_values.total_sectors += current_status.total_sectors;
initial_target_values.metadata_sectors += current_status.metadata_sectors;
+
+ SnapshotStatus snapshot_status;
+ if (!ReadSnapshotStatus(lock.get(), snapshot, &snapshot_status)) {
+ return false;
+ }
+ total_cow_file_size += snapshot_status.cow_file_size();
+ }
+
+ if (cow_file_size) {
+ *cow_file_size = total_cow_file_size;
}
SnapshotUpdateStatus initial_status;
diff --git a/fs_mgr/libsnapshot/snapshot_stats.cpp b/fs_mgr/libsnapshot/snapshot_stats.cpp
index 5da7b98..3723730 100644
--- a/fs_mgr/libsnapshot/snapshot_stats.cpp
+++ b/fs_mgr/libsnapshot/snapshot_stats.cpp
@@ -88,6 +88,15 @@
report_.set_state(state);
}
+void SnapshotMergeStats::set_cow_file_size(uint64_t cow_file_size) {
+ report_.set_cow_file_size(cow_file_size);
+ WriteState();
+}
+
+uint64_t SnapshotMergeStats::cow_file_size() {
+ return report_.cow_file_size();
+}
+
class SnapshotMergeStatsResultImpl : public SnapshotMergeStats::Result {
public:
SnapshotMergeStatsResultImpl(const SnapshotMergeReport& report,