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Commit ae2558d9 authored by Yifan Hong's avatar Yifan Hong
Browse files

libsnapshot: RemoveUpdateState on rollback. 

If rollback is detected in ProcessUpdateState, call
RemoveUpdateState and return UpdateState::Cancelled. Now that
update_engine is reponsible for initiating the merge, it can react to
this state and clean up markers appropriately.

Test: libsnapshot_test
Test: apply OTA, manually rollback (by setting the active slot), then
  inspect /metadata/ota as well as /data/misc/update_engine/prefs.

Bug: 147696014

Change-Id: Ibfee11fb50e4f4fb7c6cf02b4921b35e77b8f5a5
Merged-In: Ibfee11fb50e4f4fb7c6cf02b4921b35e77b8f5a5
parent 1d32aa1a

fs_mgr/libsnapshot/snapshot.cpp

+22 −5
Original line number Diff line number Diff line
@@ -1185,17 +1185,34 @@ bool SnapshotManager::HandleCancelledUpdate(LockedFile* lock, 


    // If all snapshots were reflashed, then cancel the entire update.

    if (AreAllSnapshotsCancelled(lock)) {

        LOG(WARNING) << "Detected re-flashing, cancelling unverified update.";

        RemoveAllUpdateState(lock, before_cancel);

        return true;

    }



    // This unverified update might be rolled back, or it might not (b/147347110

    // comment #77). Take no action, as update_engine is responsible for deciding

    // whether to cancel.

    LOG(ERROR) << "Update state is being processed before reboot, taking no action.";

    // If update has been rolled back, then cancel the entire update.

    // Client (update_engine) is responsible for doing additional cleanup work on its own states

    // when ProcessUpdateState() returns UpdateState::Cancelled.

    auto current_slot = GetCurrentSlot();

    if (current_slot != Slot::Source) {

        LOG(INFO) << "Update state is being processed while booting at " << current_slot

                  << " slot, taking no action.";

        return false;

    }



    // current_slot == Source. Attempt to detect rollbacks.

    if (access(GetRollbackIndicatorPath().c_str(), F_OK) != 0) {

        // This unverified update is not attempted. Take no action.

        PLOG(INFO) << "Rollback indicator not detected. "

                   << "Update state is being processed before reboot, taking no action.";

        return false;

    }



    LOG(WARNING) << "Detected rollback, cancelling unverified update.";

    RemoveAllUpdateState(lock, before_cancel);

    return true;

}



std::unique_ptr<LpMetadata> SnapshotManager::ReadCurrentMetadata() {

    const auto& opener = device_->GetPartitionOpener();

    uint32_t slot = SlotNumberForSlotSuffix(device_->GetSlotSuffix());