From 65db930d5ab1bf544bdc60bdac1122b0ce2d9e72 Mon Sep 17 00:00:00 2001
From: Yifan Hong <elsk@google.com>
Date: Tue, 27 Aug 2019 16:46:59 -0700
Subject: [PATCH] libsnapshot: Record COW size(s) in snapshot status file

The COW device consist of two parts: empty space in
super and the loop device. Record it in the snapshot
status file so that MapSnapshot can determine which
devices needs to be mapped.

Test: builds
Change-Id: I08fb051c080802842d2f5b43c2adeed4f04b7c5f
---
 .../libsnapshot/include/libsnapshot/snapshot.h  |  3 +++
 fs_mgr/libsnapshot/snapshot.cpp                 | 17 ++++++++++++++---
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index e3fc4f688..1f3828e5a 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -278,6 +278,9 @@ class SnapshotManager final {
         SnapshotState state;
         uint64_t device_size;
         uint64_t snapshot_size;
+        uint64_t cow_partition_size;
+        uint64_t cow_file_size;
+
         // These are non-zero when merging.
         uint64_t sectors_allocated = 0;
         uint64_t metadata_sectors = 0;
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 71457ee8d..e685cadf4 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -199,6 +199,7 @@ bool SnapshotManager::CreateSnapshot(LockedFile* lock, const std::string& name,
             .state = SnapshotState::Created,
             .device_size = device_size,
             .snapshot_size = snapshot_size,
+            .cow_file_size = cow_size,
     };
     if (!WriteSnapshotStatus(lock, name, status)) {
         PLOG(ERROR) << "Could not write snapshot status: " << name;
@@ -1310,7 +1311,7 @@ bool SnapshotManager::ReadSnapshotStatus(LockedFile* lock, const std::string& na
         return false;
     }
     auto pieces = android::base::Split(contents, " ");
-    if (pieces.size() != 5) {
+    if (pieces.size() != 7) {
         LOG(ERROR) << "Invalid status line for snapshot: " << path;
         return false;
     }
@@ -1333,11 +1334,19 @@ bool SnapshotManager::ReadSnapshotStatus(LockedFile* lock, const std::string& na
         LOG(ERROR) << "Invalid snapshot size in status line for: " << path;
         return false;
     }
-    if (!android::base::ParseUint(pieces[3], &status->sectors_allocated)) {
+    if (!android::base::ParseUint(pieces[3], &status->cow_partition_size)) {
+        LOG(ERROR) << "Invalid cow linear size in status line for: " << path;
+        return false;
+    }
+    if (!android::base::ParseUint(pieces[4], &status->cow_file_size)) {
+        LOG(ERROR) << "Invalid cow file size in status line for: " << path;
+        return false;
+    }
+    if (!android::base::ParseUint(pieces[5], &status->sectors_allocated)) {
         LOG(ERROR) << "Invalid snapshot size in status line for: " << path;
         return false;
     }
-    if (!android::base::ParseUint(pieces[4], &status->metadata_sectors)) {
+    if (!android::base::ParseUint(pieces[6], &status->metadata_sectors)) {
         LOG(ERROR) << "Invalid snapshot size in status line for: " << path;
         return false;
     }
@@ -1375,6 +1384,8 @@ bool SnapshotManager::WriteSnapshotStatus(LockedFile* lock, const std::string& n
             to_string(status.state),
             std::to_string(status.device_size),
             std::to_string(status.snapshot_size),
+            std::to_string(status.cow_partition_size),
+            std::to_string(status.cow_file_size),
             std::to_string(status.sectors_allocated),
             std::to_string(status.metadata_sectors),
     };