Merge "Offload IO to Handler thread."

4 files changed, 590 insertions, 255 deletions

diff --git a/services/core/java/com/android/server/pm/PackageHandler.java b/services/core/java/com/android/server/pm/PackageHandler.java
index 66ef93d12191..93a119c36f3d 100644
--- a/services/core/java/com/android/server/pm/PackageHandler.java
+++ b/services/core/java/com/android/server/pm/PackageHandler.java
@@ -36,7 +36,6 @@ import static com.android.server.pm.PackageManagerService.PRUNE_UNUSED_STATIC_SH
 import static com.android.server.pm.PackageManagerService.SEND_PENDING_BROADCAST;
 import static com.android.server.pm.PackageManagerService.TAG;
 import static com.android.server.pm.PackageManagerService.WRITE_PACKAGE_LIST;
-import static com.android.server.pm.PackageManagerService.WRITE_PACKAGE_RESTRICTIONS;
 import static com.android.server.pm.PackageManagerService.WRITE_SETTINGS;
 
 import android.content.Intent;
@@ -119,10 +118,7 @@ final class PackageHandler extends Handler {
                 }
             } break;
             case WRITE_SETTINGS: {
-                mPm.writeSettings();
-            } break;
-            case WRITE_PACKAGE_RESTRICTIONS: {
-                mPm.writePendingRestrictions();
+                mPm.writeSettings(/*sync=*/false);
             } break;
             case WRITE_PACKAGE_LIST: {
                 mPm.writePackageList(msg.arg1);
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 139c6ea28b7d..16a3ca0556fd 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -558,6 +558,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
     static final char RANDOM_CODEPATH_PREFIX = '-';
 
     final Handler mHandler;
+    final Handler mBackgroundHandler;
 
     final ProcessLoggingHandler mProcessLoggingHandler;
 
@@ -873,7 +874,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
     // public static final int UNUSED = 5;
     static final int POST_INSTALL = 9;
     static final int WRITE_SETTINGS = 13;
-    static final int WRITE_PACKAGE_RESTRICTIONS = 14;
+    static final int WRITE_DIRTY_PACKAGE_RESTRICTIONS = 14;
     static final int PACKAGE_VERIFIED = 15;
     static final int CHECK_PENDING_VERIFICATION = 16;
     // public static final int UNUSED = 17;
@@ -890,6 +891,8 @@ public class PackageManagerService implements PackageSender, TestUtilityService
     static final int PRUNE_UNUSED_STATIC_SHARED_LIBRARIES = 28;
     static final int DEFERRED_PENDING_KILL_INSTALL_OBSERVER = 29;
 
+    static final int WRITE_USER_PACKAGE_RESTRICTIONS = 30;
+
     static final int DEFERRED_NO_KILL_POST_DELETE_DELAY_MS = 3 * 1000;
     private static final int DEFERRED_NO_KILL_INSTALL_OBSERVER_DELAY_MS = 500;
     private static final int DEFERRED_PENDING_KILL_INSTALL_OBSERVER_DELAY_MS = 1000;
@@ -1397,28 +1400,33 @@ public class PackageManagerService implements PackageSender, TestUtilityService
                 mDirtyUsers.add(userId);
             }
         }
-        if (!mHandler.hasMessages(WRITE_PACKAGE_RESTRICTIONS)) {
-            mHandler.sendEmptyMessageDelayed(WRITE_PACKAGE_RESTRICTIONS, WRITE_SETTINGS_DELAY);
+        if (!mBackgroundHandler.hasMessages(WRITE_DIRTY_PACKAGE_RESTRICTIONS)) {
+            mBackgroundHandler.sendMessageDelayed(
+                    mBackgroundHandler.obtainMessage(WRITE_DIRTY_PACKAGE_RESTRICTIONS, this),
+                    WRITE_SETTINGS_DELAY);
         }
     }
 
     void writePendingRestrictions() {
+        final Integer[] dirtyUsers;
         synchronized (mLock) {
-            mHandler.removeMessages(WRITE_PACKAGE_RESTRICTIONS);
+            mBackgroundHandler.removeMessages(WRITE_DIRTY_PACKAGE_RESTRICTIONS);
             synchronized (mDirtyUsers) {
-                for (int userId : mDirtyUsers) {
-                    mSettings.writePackageRestrictionsLPr(userId);
+                if (mDirtyUsers.isEmpty()) {
+                    return;
                 }
+                dirtyUsers = mDirtyUsers.toArray(Integer[]::new);
                 mDirtyUsers.clear();
             }
         }
+        mSettings.writePackageRestrictions(dirtyUsers);
     }
 
-    void writeSettings() {
+    void writeSettings(boolean sync) {
         synchronized (mLock) {
             mHandler.removeMessages(WRITE_SETTINGS);
-            mHandler.removeMessages(WRITE_PACKAGE_RESTRICTIONS);
-            writeSettingsLPrTEMP();
+            mBackgroundHandler.removeMessages(WRITE_DIRTY_PACKAGE_RESTRICTIONS);
+            writeSettingsLPrTEMP(sync);
             synchronized (mDirtyUsers) {
                 mDirtyUsers.clear();
             }
@@ -1432,6 +1440,25 @@ public class PackageManagerService implements PackageSender, TestUtilityService
         }
     }
 
+    private static final Handler.Callback BACKGROUND_HANDLER_CALLBACK = new Handler.Callback() {
+        @Override
+        public boolean handleMessage(@NonNull Message msg) {
+            switch (msg.what) {
+                case WRITE_DIRTY_PACKAGE_RESTRICTIONS: {
+                    PackageManagerService pm = (PackageManagerService) msg.obj;
+                    pm.writePendingRestrictions();
+                    return true;
+                }
+                case WRITE_USER_PACKAGE_RESTRICTIONS: {
+                    final Runnable r = (Runnable) msg.obj;
+                    r.run();
+                    return true;
+                }
+            }
+            return false;
+        }
+    };
+
     public static Pair<PackageManagerService, IPackageManager> main(Context context,
             Installer installer, @NonNull DomainVerificationService domainVerificationService,
             boolean factoryTest) {
@@ -1446,7 +1473,8 @@ public class PackageManagerService implements PackageSender, TestUtilityService
         HandlerThread backgroundThread = new ServiceThread("PackageManagerBg",
                 Process.THREAD_PRIORITY_BACKGROUND, true /*allowIo*/);
         backgroundThread.start();
-        Handler backgroundHandler = new Handler(backgroundThread.getLooper());
+        Handler backgroundHandler = new Handler(backgroundThread.getLooper(),
+                BACKGROUND_HANDLER_CALLBACK);
 
         PackageManagerServiceInjector injector = new PackageManagerServiceInjector(
                 context, lock, installer, installLock, new PackageAbiHelperImpl(),
@@ -1460,7 +1488,8 @@ public class PackageManagerService implements PackageSender, TestUtilityService
                 (i, pm) -> new Settings(Environment.getDataDirectory(),
                         RuntimePermissionsPersistence.createInstance(),
                         i.getPermissionManagerServiceInternal(),
-                        domainVerificationService, backgroundHandler, lock),
+                        domainVerificationService, backgroundHandler,
+                        lock),
                 (i, pm) -> AppsFilterImpl.create(i,
                         i.getLocalService(PackageManagerInternal.class)),
                 (i, pm) -> (PlatformCompat) ServiceManager.getService("platform_compat"),
@@ -1638,6 +1667,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
         mUserNeedsBadging = new UserNeedsBadgingCache(mUserManager);
         mDomainVerificationManager = injector.getDomainVerificationManagerInternal();
         mHandler = injector.getHandler();
+        mBackgroundHandler = injector.getBackgroundHandler();
         mSharedLibraries = injector.getSharedLibrariesImpl();
 
         mApexManager = testParams.apexManager;
@@ -1828,6 +1858,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
         mMoveCallbacks = new MovePackageHelper.MoveCallbacks(FgThread.get().getLooper());
         mViewCompiler = injector.getViewCompiler();
         mSharedLibraries = mInjector.getSharedLibrariesImpl();
+        mBackgroundHandler = injector.getBackgroundHandler();
 
         mContext.getSystemService(DisplayManager.class)
                 .getDisplay(Display.DEFAULT_DISPLAY).getMetrics(mMetrics);
@@ -2902,9 +2933,9 @@ public class PackageManagerService implements PackageSender, TestUtilityService
             mPackageUsage.writeNow(mSettings.getPackagesLocked());
 
             if (mHandler.hasMessages(WRITE_SETTINGS)
-                    || mHandler.hasMessages(WRITE_PACKAGE_RESTRICTIONS)
+                    || mBackgroundHandler.hasMessages(WRITE_DIRTY_PACKAGE_RESTRICTIONS)
                     || mHandler.hasMessages(WRITE_PACKAGE_LIST)) {
-                writeSettings();
+                writeSettings(/*sync=*/true);
             }
         }
     }
@@ -3968,7 +3999,7 @@ public class PackageManagerService implements PackageSender, TestUtilityService
         synchronized (mDirtyUsers) {
             mDirtyUsers.remove(userId);
             if (mDirtyUsers.isEmpty()) {
-                mHandler.removeMessages(WRITE_PACKAGE_RESTRICTIONS);
+                mBackgroundHandler.removeMessages(WRITE_DIRTY_PACKAGE_RESTRICTIONS);
             }
         }
     }
@@ -6867,9 +6898,14 @@ public class PackageManagerService implements PackageSender, TestUtilityService
      * TODO: In the meantime, can this be moved to a schedule call?
      * TODO(b/182523293): This should be removed once we finish migration of permission storage.
      */
-    void writeSettingsLPrTEMP() {
+    void writeSettingsLPrTEMP(boolean sync) {
         mPermissionManager.writeLegacyPermissionsTEMP(mSettings.mPermissions);
-        mSettings.writeLPr(mLiveComputer);
+        mSettings.writeLPr(mLiveComputer, sync);
+    }
+
+    // Default async version.
+    void writeSettingsLPrTEMP() {
+        writeSettingsLPrTEMP(/*sync=*/false);
     }
 
     @Override
diff --git a/services/core/java/com/android/server/pm/Settings.java b/services/core/java/com/android/server/pm/Settings.java
index e33cc9ff0983..a29fa9b86297 100644
--- a/services/core/java/com/android/server/pm/Settings.java
+++ b/services/core/java/com/android/server/pm/Settings.java
@@ -29,6 +29,7 @@ import static android.os.Process.PACKAGE_INFO_GID;
 import static android.os.Process.SYSTEM_UID;
 
 import static com.android.server.pm.PackageManagerService.PLATFORM_PACKAGE_NAME;
+import static com.android.server.pm.PackageManagerService.WRITE_USER_PACKAGE_RESTRICTIONS;
 import static com.android.server.pm.SharedUidMigration.BEST_EFFORT;
 
 import android.annotation.NonNull;
@@ -56,7 +57,6 @@ import android.net.Uri;
 import android.os.Binder;
 import android.os.Build;
 import android.os.CreateAppDataArgs;
-import android.os.Environment;
 import android.os.FileUtils;
 import android.os.Handler;
 import android.os.Message;
@@ -376,6 +376,13 @@ public final class Settings implements Watchable, Snappable {
     /** The top level directory in configfs for sdcardfs to push the package->uid,userId mappings */
     private final File mKernelMappingFilename;
 
+    // Lock for user package restrictions operations.
+    private final Object mPackageRestrictionsLock = new Object();
+
+    // Pending write operations.
+    @GuardedBy("mPackageRestrictionsLock")
+    private final SparseIntArray mPendingAsyncPackageRestrictionsWrites = new SparseIntArray();
+
     /** Map from package name to settings */
     @Watched
     @VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE)
@@ -1476,31 +1483,46 @@ public final class Settings implements Watchable, Snappable {
         return (userId == UserHandle.USER_ALL) ? null : mDefaultBrowserApp.removeReturnOld(userId);
     }
 
-    private File getUserPackagesStateFile(int userId) {
-        // TODO: Implement a cleaner solution when adding tests.
+    private File getUserSystemDirectory(int userId) {
         // This instead of Environment.getUserSystemDirectory(userId) to support testing.
-        File userDir = new File(new File(mSystemDir, "users"), Integer.toString(userId));
-        return new File(userDir, "package-restrictions.xml");
+        return new File(new File(mSystemDir, "users"), Integer.toString(userId));
     }
 
-    private File getUserRuntimePermissionsFile(int userId) {
-        // TODO: Implement a cleaner solution when adding tests.
-        // This instead of Environment.getUserSystemDirectory(userId) to support testing.
-        File userDir = new File(new File(mSystemDir, "users"), Integer.toString(userId));
-        return new File(userDir, RUNTIME_PERMISSIONS_FILE_NAME);
+    // The method itself does not have to be guarded, but the file does.
+    @GuardedBy("mPackageRestrictionsLock")
+    private File getUserPackagesStateFile(int userId) {
+        return new File(getUserSystemDirectory(userId), "package-restrictions.xml");
     }
 
+    // The method itself does not have to be guarded, but the file does.
+    @GuardedBy("mPackageRestrictionsLock")
     private File getUserPackagesStateBackupFile(int userId) {
-        return new File(Environment.getUserSystemDirectory(userId),
-                "package-restrictions-backup.xml");
+        return new File(getUserSystemDirectory(userId), "package-restrictions-backup.xml");
     }
 
+    private File getUserRuntimePermissionsFile(int userId) {
+        return new File(getUserSystemDirectory(userId), RUNTIME_PERMISSIONS_FILE_NAME);
+    }
+
+    // Default version is writing restrictions asynchronously.
     void writeAllUsersPackageRestrictionsLPr() {
+        writeAllUsersPackageRestrictionsLPr(/*sync=*/false);
+    }
+
+    void writeAllUsersPackageRestrictionsLPr(boolean sync) {
         List<UserInfo> users = getAllUsers(UserManagerService.getInstance());
         if (users == null) return;
 
+        if (sync) {
+            // Cancel all pending per-user writes.
+            synchronized (mPackageRestrictionsLock) {
+                mPendingAsyncPackageRestrictionsWrites.clear();
+            }
+            mHandler.removeMessages(WRITE_USER_PACKAGE_RESTRICTIONS);
+        }
+
         for (UserInfo user : users) {
-            writePackageRestrictionsLPr(user.id);
+            writePackageRestrictionsLPr(user.id, sync);
         }
     }
 
@@ -1691,63 +1713,75 @@ public final class Settings implements Watchable, Snappable {
             Log.i(TAG, "Reading package restrictions for user=" + userId);
         }
         FileInputStream str = null;
-        File userPackagesStateFile = getUserPackagesStateFile(userId);
-        File backupFile = getUserPackagesStateBackupFile(userId);
-        if (backupFile.exists()) {
-            try {
-                str = new FileInputStream(backupFile);
-                mReadMessages.append("Reading from backup stopped packages file\n");
-                PackageManagerService.reportSettingsProblem(Log.INFO,
-                        "Need to read from backup stopped packages file");
-                if (userPackagesStateFile.exists()) {
-                    // If both the backup and normal file exist, we
-                    // ignore the normal one since it might have been
-                    // corrupted.
-                    Slog.w(PackageManagerService.TAG, "Cleaning up stopped packages file "
-                            + userPackagesStateFile);
-                    userPackagesStateFile.delete();
+
+        synchronized (mPackageRestrictionsLock) {
+            File userPackagesStateFile = getUserPackagesStateFile(userId);
+            File backupFile = getUserPackagesStateBackupFile(userId);
+            if (backupFile.exists()) {
+                try {
+                    str = new FileInputStream(backupFile);
+                    mReadMessages.append("Reading from backup stopped packages file\n");
+                    PackageManagerService.reportSettingsProblem(Log.INFO,
+                            "Need to read from backup stopped packages file");
+                    if (userPackagesStateFile.exists()) {
+                        // If both the backup and normal file exist, we
+                        // ignore the normal one since it might have been
+                        // corrupted.
+                        Slog.w(PackageManagerService.TAG, "Cleaning up stopped packages file "
+                                + userPackagesStateFile);
+                        userPackagesStateFile.delete();
+                    }
+                } catch (java.io.IOException e) {
+                    // We'll try for the normal settings file.
+                }
+            }
+
+            if (str == null && userPackagesStateFile.exists()) {
+                try {
+                    str = new FileInputStream(userPackagesStateFile);
+                    if (DEBUG_MU) Log.i(TAG, "Reading " + userPackagesStateFile);
+                } catch (java.io.IOException e) {
+                    mReadMessages.append("Error reading: " + e.toString());
+                    PackageManagerService.reportSettingsProblem(Log.ERROR,
+                            "Error reading settings: " + e);
+                    Slog.wtf(TAG, "Error reading package manager stopped packages", e);
                 }
-            } catch (java.io.IOException e) {
-                // We'll try for the normal settings file.
             }
         }
 
-        try {
-            if (str == null) {
-                if (!userPackagesStateFile.exists()) {
-                    mReadMessages.append("No stopped packages file found\n");
-                    PackageManagerService.reportSettingsProblem(Log.INFO,
-                            "No stopped packages file; "
+        if (str == null) {
+            mReadMessages.append("No stopped packages file found\n");
+            PackageManagerService.reportSettingsProblem(Log.INFO,
+                    "No stopped packages file; "
                             + "assuming all started");
-                    // At first boot, make sure no packages are stopped.
-                    // We usually want to have third party apps initialize
-                    // in the stopped state, but not at first boot.  Also
-                    // consider all applications to be installed.
-                    for (PackageSetting pkg : mPackages.values()) {
-                        pkg.setUserState(userId, 0, COMPONENT_ENABLED_STATE_DEFAULT,
-                                true  /*installed*/,
-                                false /*stopped*/,
-                                false /*notLaunched*/,
-                                false /*hidden*/,
-                                0 /*distractionFlags*/,
-                                null /*suspendParams*/,
-                                false /*instantApp*/,
-                                false /*virtualPreload*/,
-                                null /*lastDisableAppCaller*/,
-                                null /*enabledComponents*/,
-                                null /*disabledComponents*/,
-                                PackageManager.INSTALL_REASON_UNKNOWN,
-                                PackageManager.UNINSTALL_REASON_UNKNOWN,
-                                null /*harmfulAppWarning*/,
-                                null /* splashScreenTheme*/,
-                                0 /*firstInstallTime*/
-                        );
-                    }
-                    return;
-                }
-                str = new FileInputStream(userPackagesStateFile);
-                if (DEBUG_MU) Log.i(TAG, "Reading " + userPackagesStateFile);
+            // At first boot, make sure no packages are stopped.
+            // We usually want to have third party apps initialize
+            // in the stopped state, but not at first boot.  Also
+            // consider all applications to be installed.
+            for (PackageSetting pkg : mPackages.values()) {
+                pkg.setUserState(userId, 0, COMPONENT_ENABLED_STATE_DEFAULT,
+                        true  /*installed*/,
+                        false /*stopped*/,
+                        false /*notLaunched*/,
+                        false /*hidden*/,
+                        0 /*distractionFlags*/,
+                        null /*suspendParams*/,
+                        false /*instantApp*/,
+                        false /*virtualPreload*/,
+                        null /*lastDisableAppCaller*/,
+                        null /*enabledComponents*/,
+                        null /*disabledComponents*/,
+                        PackageManager.INSTALL_REASON_UNKNOWN,
+                        PackageManager.UNINSTALL_REASON_UNKNOWN,
+                        null /*harmfulAppWarning*/,
+                        null /* splashScreenTheme*/,
+                        0 /*firstInstallTime*/
+                );
             }
+            return;
+        }
+
+        try {
             final TypedXmlPullParser parser = Xml.resolvePullParser(str);
 
             int type;
@@ -2070,179 +2104,247 @@ public final class Settings implements Watchable, Snappable {
         }
     }
 
+    // Default version is writing restrictions asynchronously.
     void writePackageRestrictionsLPr(int userId) {
+        writePackageRestrictionsLPr(userId, /*sync=*/false);
+    }
+
+    void writePackageRestrictionsLPr(int userId, boolean sync) {
         invalidatePackageCache();
 
+        final long startTime = SystemClock.uptimeMillis();
+
+        if (sync) {
+            writePackageRestrictions(userId, startTime, sync);
+        } else {
+            if (DEBUG_MU) {
+                Log.i(TAG, "Scheduling deferred IO sync for user=" + userId);
+            }
+            synchronized (mPackageRestrictionsLock) {
+                int pending = mPendingAsyncPackageRestrictionsWrites.get(userId, 0) + 1;
+                mPendingAsyncPackageRestrictionsWrites.put(userId, pending);
+            }
+            Runnable r = () -> writePackageRestrictions(userId, startTime, sync);
+            mHandler.obtainMessage(WRITE_USER_PACKAGE_RESTRICTIONS, r).sendToTarget();
+        }
+    }
+
+    void writePackageRestrictions(Integer[] userIds) {
+        invalidatePackageCache();
+        final long startTime = SystemClock.uptimeMillis();
+        for (int userId : userIds) {
+            writePackageRestrictions(userId, startTime, /*sync=*/true);
+        }
+    }
+
+    void writePackageRestrictions(int userId, long startTime, boolean sync) {
         if (DEBUG_MU) {
             Log.i(TAG, "Writing package restrictions for user=" + userId);
         }
-        final long startTime = SystemClock.uptimeMillis();
 
-        // Keep the old stopped packages around until we know the new ones have
-        // been successfully written.
-        File userPackagesStateFile = getUserPackagesStateFile(userId);
-        File backupFile = getUserPackagesStateBackupFile(userId);
-        new File(userPackagesStateFile.getParent()).mkdirs();
-        if (userPackagesStateFile.exists()) {
-            // Presence of backup settings file indicates that we failed
-            // to persist packages earlier. So preserve the older
-            // backup for future reference since the current packages
-            // might have been corrupted.
-            if (!backupFile.exists()) {
-                if (!userPackagesStateFile.renameTo(backupFile)) {
-                    Slog.wtf(PackageManagerService.TAG,
-                            "Unable to backup user packages state file, "
-                            + "current changes will be lost at reboot");
+        final File userPackagesStateFile;
+        final File backupFile;
+        final FileOutputStream fstr;
+
+        synchronized (mPackageRestrictionsLock) {
+            if (!sync) {
+                int pending = mPendingAsyncPackageRestrictionsWrites.get(userId, 0) - 1;
+                if (pending < 0) {
+                    Log.i(TAG, "Cancel writing package restrictions for user=" + userId);
                     return;
                 }
-            } else {
-                userPackagesStateFile.delete();
-                Slog.w(PackageManagerService.TAG, "Preserving older stopped packages backup");
+                mPendingAsyncPackageRestrictionsWrites.put(userId, pending);
+            }
+
+            // Keep the old stopped packages around until we know the new ones have
+            // been successfully written.
+            userPackagesStateFile = getUserPackagesStateFile(userId);
+            backupFile = getUserPackagesStateBackupFile(userId);
+            new File(userPackagesStateFile.getParent()).mkdirs();
+            if (userPackagesStateFile.exists()) {
+                // Presence of backup settings file indicates that we failed
+                // to persist packages earlier. So preserve the older
+                // backup for future reference since the current packages
+                // might have been corrupted.
+                if (!backupFile.exists()) {
+                    if (!userPackagesStateFile.renameTo(backupFile)) {
+                        Slog.wtf(PackageManagerService.TAG,
+                                "Unable to backup user packages state file, "
+                                        + "current changes will be lost at reboot");
+                        return;
+                    }
+                } else {
+                    userPackagesStateFile.delete();
+                    Slog.w(PackageManagerService.TAG, "Preserving older stopped packages backup");
+                }
+            }
+
+            try {
+                fstr = new FileOutputStream(userPackagesStateFile);
+                // File is created, set permissions.
+                FileUtils.setPermissions(userPackagesStateFile.toString(),
+                        FileUtils.S_IRUSR | FileUtils.S_IWUSR
+                                | FileUtils.S_IRGRP | FileUtils.S_IWGRP,
+                        -1, -1);
+            } catch (java.io.IOException e) {
+                Slog.wtf(PackageManagerService.TAG,
+                        "Unable to write package manager user packages state, "
+                                + " current changes will be lost at reboot", e);
+                return;
             }
         }
 
         try {
-            final FileOutputStream fstr = new FileOutputStream(userPackagesStateFile);
-            final TypedXmlSerializer serializer = Xml.resolveSerializer(fstr);
-            serializer.startDocument(null, true);
-            serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
+            synchronized (mLock) {
+                final TypedXmlSerializer serializer = Xml.resolveSerializer(fstr);
+                serializer.startDocument(null, true);
+                serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output",
+                        true);
 
-            serializer.startTag(null, TAG_PACKAGE_RESTRICTIONS);
+                serializer.startTag(null, TAG_PACKAGE_RESTRICTIONS);
 
-            if (DEBUG_MU) {
-                Slogf.i(TAG, "Writing %s (%d packages)", userPackagesStateFile,
-                        mPackages.values().size());
-            }
-            for (final PackageSetting pkg : mPackages.values()) {
-                final PackageUserStateInternal ustate = pkg.readUserState(userId);
                 if (DEBUG_MU) {
-                    Log.v(TAG, "  pkg=" + pkg.getPackageName()
-                            + ", installed=" + ustate.isInstalled()
-                            + ", state=" + ustate.getEnabledState());
-                }
+                    Slogf.i(TAG, "Writing %s (%d packages)", userPackagesStateFile,
+                            mPackages.values().size());
+                }
+                for (final PackageSetting pkg : mPackages.values()) {
+                    final PackageUserStateInternal ustate = pkg.readUserState(userId);
+                    if (DEBUG_MU) {
+                        Log.v(TAG, "  pkg=" + pkg.getPackageName()
+                                + ", installed=" + ustate.isInstalled()
+                                + ", state=" + ustate.getEnabledState());
+                    }
 
-                serializer.startTag(null, TAG_PACKAGE);
-                serializer.attribute(null, ATTR_NAME, pkg.getPackageName());
-                if (ustate.getCeDataInode() != 0) {
-                    serializer.attributeLong(null, ATTR_CE_DATA_INODE, ustate.getCeDataInode());
-                }
-                if (!ustate.isInstalled()) {
-                    serializer.attributeBoolean(null, ATTR_INSTALLED, false);
-                }
-                if (ustate.isStopped()) {
-                    serializer.attributeBoolean(null, ATTR_STOPPED, true);
-                }
-                if (ustate.isNotLaunched()) {
-                    serializer.attributeBoolean(null, ATTR_NOT_LAUNCHED, true);
-                }
-                if (ustate.isHidden()) {
-                    serializer.attributeBoolean(null, ATTR_HIDDEN, true);
-                }
-                if (ustate.getDistractionFlags() != 0) {
-                    serializer.attributeInt(null, ATTR_DISTRACTION_FLAGS,
-                            ustate.getDistractionFlags());
-                }
-                if (ustate.isSuspended()) {
-                    serializer.attributeBoolean(null, ATTR_SUSPENDED, true);
-                }
-                if (ustate.isInstantApp()) {
-                    serializer.attributeBoolean(null, ATTR_INSTANT_APP, true);
-                }
-                if (ustate.isVirtualPreload()) {
-                    serializer.attributeBoolean(null, ATTR_VIRTUAL_PRELOAD, true);
-                }
-                if (ustate.getEnabledState() != COMPONENT_ENABLED_STATE_DEFAULT) {
-                    serializer.attributeInt(null, ATTR_ENABLED, ustate.getEnabledState());
-                    if (ustate.getLastDisableAppCaller() != null) {
-                        serializer.attribute(null, ATTR_ENABLED_CALLER,
-                                ustate.getLastDisableAppCaller());
+                    serializer.startTag(null, TAG_PACKAGE);
+                    serializer.attribute(null, ATTR_NAME, pkg.getPackageName());
+                    if (ustate.getCeDataInode() != 0) {
+                        serializer.attributeLong(null, ATTR_CE_DATA_INODE, ustate.getCeDataInode());
                     }
-                }
-                if (ustate.getInstallReason() != PackageManager.INSTALL_REASON_UNKNOWN) {
-                    serializer.attributeInt(null, ATTR_INSTALL_REASON,
-                            ustate.getInstallReason());
-                }
-                serializer.attributeLongHex(null, ATTR_FIRST_INSTALL_TIME,
-                        ustate.getFirstInstallTime());
-                if (ustate.getUninstallReason() != PackageManager.UNINSTALL_REASON_UNKNOWN) {
-                    serializer.attributeInt(null, ATTR_UNINSTALL_REASON,
-                            ustate.getUninstallReason());
-                }
-                if (ustate.getHarmfulAppWarning() != null) {
-                    serializer.attribute(null, ATTR_HARMFUL_APP_WARNING,
-                            ustate.getHarmfulAppWarning());
-                }
-                if (ustate.getSplashScreenTheme() != null) {
-                    serializer.attribute(null, ATTR_SPLASH_SCREEN_THEME,
-                            ustate.getSplashScreenTheme());
-                }
-                if (ustate.isSuspended()) {
-                    for (int i = 0; i < ustate.getSuspendParams().size(); i++) {
-                        final String suspendingPackage = ustate.getSuspendParams().keyAt(i);
-                        serializer.startTag(null, TAG_SUSPEND_PARAMS);
-                        serializer.attribute(null, ATTR_SUSPENDING_PACKAGE, suspendingPackage);
-                        final SuspendParams params =
-                                ustate.getSuspendParams().valueAt(i);
-                        if (params != null) {
-                            params.saveToXml(serializer);
+                    if (!ustate.isInstalled()) {
+                        serializer.attributeBoolean(null, ATTR_INSTALLED, false);
+                    }
+                    if (ustate.isStopped()) {
+                        serializer.attributeBoolean(null, ATTR_STOPPED, true);
+                    }
+                    if (ustate.isNotLaunched()) {
+                        serializer.attributeBoolean(null, ATTR_NOT_LAUNCHED, true);
+                    }
+                    if (ustate.isHidden()) {
+                        serializer.attributeBoolean(null, ATTR_HIDDEN, true);
+                    }
+                    if (ustate.getDistractionFlags() != 0) {
+                        serializer.attributeInt(null, ATTR_DISTRACTION_FLAGS,
+                                ustate.getDistractionFlags());
+                    }
+                    if (ustate.isSuspended()) {
+                        serializer.attributeBoolean(null, ATTR_SUSPENDED, true);
+                    }
+                    if (ustate.isInstantApp()) {
+                        serializer.attributeBoolean(null, ATTR_INSTANT_APP, true);
+                    }
+                    if (ustate.isVirtualPreload()) {
+                        serializer.attributeBoolean(null, ATTR_VIRTUAL_PRELOAD, true);
+                    }
+                    if (ustate.getEnabledState() != COMPONENT_ENABLED_STATE_DEFAULT) {
+                        serializer.attributeInt(null, ATTR_ENABLED, ustate.getEnabledState());
+                        if (ustate.getLastDisableAppCaller() != null) {
+                            serializer.attribute(null, ATTR_ENABLED_CALLER,
+                                    ustate.getLastDisableAppCaller());
                         }
-                        serializer.endTag(null, TAG_SUSPEND_PARAMS);
                     }
-                }
-                final ArraySet<String> enabledComponents = ustate.getEnabledComponents();
-                if (enabledComponents != null && enabledComponents.size() > 0) {
-                    serializer.startTag(null, TAG_ENABLED_COMPONENTS);
-                    for (int i = 0; i < enabledComponents.size(); i++) {
-                        serializer.startTag(null, TAG_ITEM);
-                        serializer.attribute(null, ATTR_NAME,
-                                enabledComponents.valueAt(i));
-                        serializer.endTag(null, TAG_ITEM);
+                    if (ustate.getInstallReason() != PackageManager.INSTALL_REASON_UNKNOWN) {
+                        serializer.attributeInt(null, ATTR_INSTALL_REASON,
+                                ustate.getInstallReason());
                     }
-                    serializer.endTag(null, TAG_ENABLED_COMPONENTS);
-                }
-                final ArraySet<String> disabledComponents = ustate.getDisabledComponents();
-                if (disabledComponents != null && disabledComponents.size() > 0) {
-                    serializer.startTag(null, TAG_DISABLED_COMPONENTS);
-                    for (int i = 0; i < disabledComponents.size(); i++) {
-                        serializer.startTag(null, TAG_ITEM);
-                        serializer.attribute(null, ATTR_NAME,
-                                disabledComponents.valueAt(i));
-                        serializer.endTag(null, TAG_ITEM);
+                    serializer.attributeLongHex(null, ATTR_FIRST_INSTALL_TIME,
+                            ustate.getFirstInstallTime());
+                    if (ustate.getUninstallReason() != PackageManager.UNINSTALL_REASON_UNKNOWN) {
+                        serializer.attributeInt(null, ATTR_UNINSTALL_REASON,
+                                ustate.getUninstallReason());
+                    }
+                    if (ustate.getHarmfulAppWarning() != null) {
+                        serializer.attribute(null, ATTR_HARMFUL_APP_WARNING,
+                                ustate.getHarmfulAppWarning());
+                    }
+                    if (ustate.getSplashScreenTheme() != null) {
+                        serializer.attribute(null, ATTR_SPLASH_SCREEN_THEME,
+                                ustate.getSplashScreenTheme());
+                    }
+                    if (ustate.isSuspended()) {
+                        for (int i = 0; i < ustate.getSuspendParams().size(); i++) {
+                            final String suspendingPackage = ustate.getSuspendParams().keyAt(i);
+                            serializer.startTag(null, TAG_SUSPEND_PARAMS);
+                            serializer.attribute(null, ATTR_SUSPENDING_PACKAGE, suspendingPackage);
+                            final SuspendParams params =
+                                    ustate.getSuspendParams().valueAt(i);
+                            if (params != null) {
+                                params.saveToXml(serializer);
+                            }
+                            serializer.endTag(null, TAG_SUSPEND_PARAMS);
+                        }
+                    }
+                    final ArraySet<String> enabledComponents = ustate.getEnabledComponents();
+                    if (enabledComponents != null && enabledComponents.size() > 0) {
+                        serializer.startTag(null, TAG_ENABLED_COMPONENTS);
+                        for (int i = 0; i < enabledComponents.size(); i++) {
+                            serializer.startTag(null, TAG_ITEM);
+                            serializer.attribute(null, ATTR_NAME,
+                                    enabledComponents.valueAt(i));
+                            serializer.endTag(null, TAG_ITEM);
+                        }
+                        serializer.endTag(null, TAG_ENABLED_COMPONENTS);
+                    }
+                    final ArraySet<String> disabledComponents = ustate.getDisabledComponents();
+                    if (disabledComponents != null && disabledComponents.size() > 0) {
+                        serializer.startTag(null, TAG_DISABLED_COMPONENTS);
+                        for (int i = 0; i < disabledComponents.size(); i++) {
+                            serializer.startTag(null, TAG_ITEM);
+                            serializer.attribute(null, ATTR_NAME,
+                                    disabledComponents.valueAt(i));
+                            serializer.endTag(null, TAG_ITEM);
+                        }
+                        serializer.endTag(null, TAG_DISABLED_COMPONENTS);
                     }
-                    serializer.endTag(null, TAG_DISABLED_COMPONENTS);
-                }
 
-                serializer.endTag(null, TAG_PACKAGE);
-            }
+                    serializer.endTag(null, TAG_PACKAGE);
+                }
 
-            writePreferredActivitiesLPr(serializer, userId, true);
-            writePersistentPreferredActivitiesLPr(serializer, userId);
-            writeCrossProfileIntentFiltersLPr(serializer, userId);
-            writeDefaultAppsLPr(serializer, userId);
-            writeBlockUninstallPackagesLPr(serializer, userId);
+                writePreferredActivitiesLPr(serializer, userId, true);
+                writePersistentPreferredActivitiesLPr(serializer, userId);
+                writeCrossProfileIntentFiltersLPr(serializer, userId);
+                writeDefaultAppsLPr(serializer, userId);
+                writeBlockUninstallPackagesLPr(serializer, userId);
 
-            serializer.endTag(null, TAG_PACKAGE_RESTRICTIONS);
+                serializer.endTag(null, TAG_PACKAGE_RESTRICTIONS);
 
-            serializer.endDocument();
+                serializer.endDocument();
+            }
 
             fstr.flush();
             FileUtils.sync(fstr);
-            fstr.close();
+            IoUtils.closeQuietly(fstr);
 
-            // New settings successfully written, old ones are no longer
-            // needed.
-            backupFile.delete();
-            FileUtils.setPermissions(userPackagesStateFile.toString(),
-                    FileUtils.S_IRUSR|FileUtils.S_IWUSR
-                    |FileUtils.S_IRGRP|FileUtils.S_IWGRP,
-                    -1, -1);
+            synchronized (mPackageRestrictionsLock) {
+                // File is created, set permissions.
+                FileUtils.setPermissions(userPackagesStateFile.toString(),
+                        FileUtils.S_IRUSR | FileUtils.S_IWUSR
+                                | FileUtils.S_IRGRP | FileUtils.S_IWGRP,
+                        -1, -1);
+                // New settings successfully written, old ones are no longer needed.
+                backupFile.delete();
+            }
+
+            if (DEBUG_MU) {
+                Log.i(TAG, "New settings successfully written for user=" + userId + ": "
+                        + userPackagesStateFile);
+            }
 
             com.android.internal.logging.EventLogTags.writeCommitSysConfigFile(
                     "package-user-" + userId, SystemClock.uptimeMillis() - startTime);
 
             // Done, all is good!
             return;
-        } catch(java.io.IOException e) {
+        } catch (java.io.IOException e) {
             Slog.wtf(PackageManagerService.TAG,
                     "Unable to write package manager user packages state, "
                     + " current changes will be lost at reboot", e);
@@ -2453,7 +2555,7 @@ public final class Settings implements Watchable, Snappable {
         }
     }
 
-    void writeLPr(@NonNull Computer computer) {
+    void writeLPr(@NonNull Computer computer, boolean sync) {
         //Debug.startMethodTracing("/data/system/packageprof", 8 * 1024 * 1024);
 
         final long startTime = SystemClock.uptimeMillis();
@@ -2578,7 +2680,7 @@ public final class Settings implements Watchable, Snappable {
 
             writeKernelMappingLPr();
             writePackageListLPr();
-            writeAllUsersPackageRestrictionsLPr();
+            writeAllUsersPackageRestrictionsLPr(sync);
             writeAllRuntimePermissionsLPr();
             com.android.internal.logging.EventLogTags.writeCommitSysConfigFile(
                     "package", SystemClock.uptimeMillis() - startTime);
@@ -3213,7 +3315,7 @@ public final class Settings implements Watchable, Snappable {
             mBackupStoppedPackagesFilename.delete();
             mStoppedPackagesFilename.delete();
             // Migrate to new file format
-            writePackageRestrictionsLPr(UserHandle.USER_SYSTEM);
+            writePackageRestrictionsLPr(UserHandle.USER_SYSTEM, /*sync=*/true);
         } else {
             for (UserInfo user : users) {
                 readPackageRestrictionsLPr(user.id, originalFirstInstallTimes);
@@ -4284,10 +4386,15 @@ public final class Settings implements Watchable, Snappable {
             entry.getValue().removeUser(userId);
         }
         mPreferredActivities.remove(userId);
-        File file = getUserPackagesStateFile(userId);
-        file.delete();
-        file = getUserPackagesStateBackupFile(userId);
-        file.delete();
+
+        synchronized (mPackageRestrictionsLock) {
+            File file = getUserPackagesStateFile(userId);
+            file.delete();
+            file = getUserPackagesStateBackupFile(userId);
+            file.delete();
+            mPendingAsyncPackageRestrictionsWrites.delete(userId);
+        }
+
         removeCrossProfileIntentFiltersLPw(userId);
 
         mRuntimePermissionsPersistence.onUserRemoved(userId);
@@ -4332,7 +4439,7 @@ public final class Settings implements Watchable, Snappable {
         if (mVerifierDeviceIdentity == null) {
             mVerifierDeviceIdentity = VerifierDeviceIdentity.generate();
 
-            writeLPr(computer);
+            writeLPr(computer, /*sync=*/false);
         }
 
         return mVerifierDeviceIdentity;
diff --git a/services/tests/servicestests/src/com/android/server/pm/PackageManagerSettingsTests.java b/services/tests/servicestests/src/com/android/server/pm/PackageManagerSettingsTests.java
index 88932b06db82..3727d660f9a7 100644
--- a/services/tests/servicestests/src/com/android/server/pm/PackageManagerSettingsTests.java
+++ b/services/tests/servicestests/src/com/android/server/pm/PackageManagerSettingsTests.java
@@ -25,6 +25,8 @@ import static android.content.pm.SuspendDialogInfo.BUTTON_ACTION_UNSUSPEND;
 import static android.content.pm.parsing.FrameworkParsingPackageUtils.parsePublicKey;
 import static android.content.res.Resources.ID_NULL;
 
+import static com.android.server.pm.PackageManagerService.WRITE_USER_PACKAGE_RESTRICTIONS;
+
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.not;
@@ -32,6 +34,7 @@ import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.CoreMatchers.nullValue;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotSame;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
@@ -45,6 +48,7 @@ import android.content.pm.PackageManager;
 import android.content.pm.SuspendDialogInfo;
 import android.content.pm.UserInfo;
 import android.os.BaseBundle;
+import android.os.Message;
 import android.os.PersistableBundle;
 import android.os.Process;
 import android.os.UserHandle;
@@ -69,6 +73,7 @@ import com.android.server.pm.pkg.PackageUserState;
 import com.android.server.pm.pkg.PackageUserStateInternal;
 import com.android.server.pm.pkg.SuspendParams;
 import com.android.server.pm.verify.domain.DomainVerificationManagerInternal;
+import com.android.server.testutils.TestHandler;
 import com.android.server.utils.Watchable;
 import com.android.server.utils.WatchableTester;
 import com.android.server.utils.WatchedArrayMap;
@@ -91,6 +96,7 @@ import java.security.PublicKey;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.PriorityQueue;
 import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.CountDownLatch;
@@ -116,6 +122,10 @@ public class PackageManagerSettingsTests {
 
     final ArrayMap<String, Long> mOrigFirstInstallTimes = new ArrayMap<>();
 
+    final TestHandler mHandler = new TestHandler((@NonNull Message msg) -> {
+        return true;
+    });
+
     @Before
     public void initializeMocks() {
         MockitoAnnotations.initMocks(this);
@@ -150,7 +160,7 @@ public class PackageManagerSettingsTests {
         assertThat(settings.readLPw(computer, createFakeUsers()), is(true));
 
         // write out, read back in and verify the same
-        settings.writeLPr(computer);
+        settings.writeLPr(computer, /*sync=*/true);
         assertThat(settings.readLPw(computer, createFakeUsers()), is(true));
         verifyKeySetMetaData(settings);
     }
@@ -180,7 +190,7 @@ public class PackageManagerSettingsTests {
         writeOldFiles();
         Settings settings = makeSettings();
         assertThat(settings.readLPw(computer, createFakeUsers()), is(true));
-        settings.writeLPr(computer);
+        settings.writeLPr(computer, /*sync=*/true);
 
         // Create Settings again to make it read from the new files
         settings = makeSettings();
@@ -326,14 +336,14 @@ public class PackageManagerSettingsTests {
                 .setNeutralButtonAction(BUTTON_ACTION_UNSUSPEND)
                 .build();
 
-        ps1.modifyUserState(0).putSuspendParams( "suspendingPackage1",
+        ps1.modifyUserState(0).putSuspendParams("suspendingPackage1",
                 new SuspendParams(dialogInfo1, appExtras1, launcherExtras1));
-        ps1.modifyUserState(0).putSuspendParams( "suspendingPackage2",
+        ps1.modifyUserState(0).putSuspendParams("suspendingPackage2",
                 new SuspendParams(dialogInfo2, appExtras2, launcherExtras2));
         settingsUnderTest.mPackages.put(PACKAGE_NAME_1, ps1);
         watcher.verifyChangeReported("put package 1");
 
-        ps2.modifyUserState(0).putSuspendParams( "suspendingPackage3",
+        ps2.modifyUserState(0).putSuspendParams("suspendingPackage3",
                 new SuspendParams(null, appExtras1, null));
         settingsUnderTest.mPackages.put(PACKAGE_NAME_2, ps2);
         watcher.verifyChangeReported("put package 2");
@@ -342,7 +352,7 @@ public class PackageManagerSettingsTests {
         settingsUnderTest.mPackages.put(PACKAGE_NAME_3, ps3);
         watcher.verifyChangeReported("put package 3");
 
-        settingsUnderTest.writePackageRestrictionsLPr(0);
+        settingsUnderTest.writePackageRestrictionsLPr(0, /*sync=*/true);
         watcher.verifyChangeReported("writePackageRestrictions");
 
         settingsUnderTest.mPackages.clear();
@@ -407,48 +417,232 @@ public class PackageManagerSettingsTests {
         assertThat(defaultSetting.getUserStateOrDefault(0).isSuspended(), is(false));
     }
 
-    @Test
-    public void testReadWritePackageRestrictions_distractionFlags() {
-        final Settings settingsUnderTest = makeSettings();
+    private void populateDefaultSettings(Settings settings) {
+        settings.mPackages.clear();
+        settings.mPackages.put(PACKAGE_NAME_1, createPackageSetting(PACKAGE_NAME_1));
+        settings.mPackages.put(PACKAGE_NAME_2, createPackageSetting(PACKAGE_NAME_2));
+        settings.mPackages.put(PACKAGE_NAME_3, createPackageSetting(PACKAGE_NAME_3));
+    }
+
+    private void verifyDefaultDistractionFlags(Settings settings) {
+        final PackageUserState readPus1 = settings.mPackages.get(PACKAGE_NAME_1)
+                .readUserState(0);
+        assertThat(readPus1.getDistractionFlags(), is(0));
+
+        final PackageUserState readPus2 = settings.mPackages.get(PACKAGE_NAME_2)
+                .readUserState(0);
+        assertThat(readPus2.getDistractionFlags(), is(0));
+
+        final PackageUserState readPus3 = settings.mPackages.get(PACKAGE_NAME_3)
+                .readUserState(0);
+        assertThat(readPus3.getDistractionFlags(), is(0));
+    }
+
+    private void populateDistractionFlags(Settings settings) {
+        settings.mPackages.clear();
         final PackageSetting ps1 = createPackageSetting(PACKAGE_NAME_1);
         final PackageSetting ps2 = createPackageSetting(PACKAGE_NAME_2);
         final PackageSetting ps3 = createPackageSetting(PACKAGE_NAME_3);
 
         final int distractionFlags1 = PackageManager.RESTRICTION_HIDE_FROM_SUGGESTIONS;
         ps1.setDistractionFlags(distractionFlags1, 0);
-        settingsUnderTest.mPackages.put(PACKAGE_NAME_1, ps1);
+        settings.mPackages.put(PACKAGE_NAME_1, ps1);
 
         final int distractionFlags2 = PackageManager.RESTRICTION_HIDE_NOTIFICATIONS
                 | PackageManager.RESTRICTION_HIDE_FROM_SUGGESTIONS;
         ps2.setDistractionFlags(distractionFlags2, 0);
-        settingsUnderTest.mPackages.put(PACKAGE_NAME_2, ps2);
+        settings.mPackages.put(PACKAGE_NAME_2, ps2);
 
         final int distractionFlags3 = PackageManager.RESTRICTION_NONE;
         ps3.setDistractionFlags(distractionFlags3, 0);
-        settingsUnderTest.mPackages.put(PACKAGE_NAME_3, ps3);
+        settings.mPackages.put(PACKAGE_NAME_3, ps3);
+    }
 
-        settingsUnderTest.writePackageRestrictionsLPr(0);
+    private void verifyDistractionFlags(Settings settings) {
+        final int distractionFlags1 = PackageManager.RESTRICTION_HIDE_FROM_SUGGESTIONS;
+        final int distractionFlags2 = PackageManager.RESTRICTION_HIDE_NOTIFICATIONS
+                | PackageManager.RESTRICTION_HIDE_FROM_SUGGESTIONS;
+        final int distractionFlags3 = PackageManager.RESTRICTION_NONE;
 
-        settingsUnderTest.mPackages.clear();
-        settingsUnderTest.mPackages.put(PACKAGE_NAME_1, createPackageSetting(PACKAGE_NAME_1));
-        settingsUnderTest.mPackages.put(PACKAGE_NAME_2, createPackageSetting(PACKAGE_NAME_2));
-        settingsUnderTest.mPackages.put(PACKAGE_NAME_3, createPackageSetting(PACKAGE_NAME_3));
-        // now read and verify
-        settingsUnderTest.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
-        final PackageUserState readPus1 = settingsUnderTest.mPackages.get(PACKAGE_NAME_1)
+        final PackageUserState readPus1 = settings.mPackages.get(PACKAGE_NAME_1)
                 .readUserState(0);
         assertThat(readPus1.getDistractionFlags(), is(distractionFlags1));
 
-        final PackageUserState readPus2 = settingsUnderTest.mPackages.get(PACKAGE_NAME_2)
+        final PackageUserState readPus2 = settings.mPackages.get(PACKAGE_NAME_2)
                 .readUserState(0);
         assertThat(readPus2.getDistractionFlags(), is(distractionFlags2));
 
-        final PackageUserState readPus3 = settingsUnderTest.mPackages.get(PACKAGE_NAME_3)
+        final PackageUserState readPus3 = settings.mPackages.get(PACKAGE_NAME_3)
                 .readUserState(0);
         assertThat(readPus3.getDistractionFlags(), is(distractionFlags3));
     }
 
     @Test
+    public void testReadWritePackageRestrictions_distractionFlags() {
+        final Settings settingsUnderTest = makeSettings();
+
+        populateDistractionFlags(settingsUnderTest);
+        settingsUnderTest.writePackageRestrictionsLPr(0, /*sync=*/true);
+
+        // now read and verify
+        populateDefaultSettings(settingsUnderTest);
+        settingsUnderTest.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsUnderTest);
+    }
+
+    @Test
+    public void testReadWritePackageRestrictionsAsync() {
+        final Settings settingsWrite = makeSettings();
+        final Settings settingsRead = makeSettings();
+        mHandler.clear();
+
+        // Initial empty state.
+        settingsWrite.removeUserLPw(0);
+
+        // Schedule 3 async writes.
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+
+        PriorityQueue<TestHandler.MsgInfo> messages = mHandler.getPendingMessages();
+        assertEquals(3, messages.size());
+        final Runnable asyncWrite1 = (Runnable) messages.poll().message.obj;
+        final Runnable asyncWrite2 = (Runnable) messages.poll().message.obj;
+        final Runnable asyncWrite3 = (Runnable) messages.poll().message.obj;
+        mHandler.clear();
+
+        // First read should read old data.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDefaultDistractionFlags(settingsRead);
+
+        // 1st write: with flags.
+        populateDistractionFlags(settingsWrite);
+        asyncWrite1.run();
+
+        // New data.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsRead);
+
+        // 2nd write: without.
+        populateDefaultSettings(settingsWrite);
+        asyncWrite2.run();
+
+        // Default data.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDefaultDistractionFlags(settingsRead);
+
+        // 3rd write: with flags.
+        populateDistractionFlags(settingsWrite);
+        asyncWrite3.run();
+
+        // New data.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsRead);
+    }
+
+    @Test
+    public void testReadWritePackageRestrictionsAsyncUserRemoval() {
+        final Settings settingsWrite = makeSettings();
+        final Settings settingsRead = makeSettings();
+        mHandler.clear();
+
+        // Initial empty state.
+        settingsWrite.removeUserLPw(0);
+
+        // 2 async writes.
+        populateDistractionFlags(settingsWrite);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+
+        PriorityQueue<TestHandler.MsgInfo> messages = mHandler.getPendingMessages();
+        assertEquals(2, messages.size());
+        final Runnable asyncWrite1 = (Runnable) messages.poll().message.obj;
+        final Runnable asyncWrite2 = (Runnable) messages.poll().message.obj;
+        mHandler.clear();
+
+        // First read should not read anything.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDefaultDistractionFlags(settingsRead);
+
+        // 1st write.
+        asyncWrite1.run();
+
+        // Second read should read new data.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsRead);
+
+        // Now remove the user.
+        settingsWrite.removeUserLPw(0);
+
+        // 2nd write.
+        asyncWrite2.run();
+
+        // Re-read and verify that nothing was read.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDefaultDistractionFlags(settingsRead);
+    }
+
+    @Test
+    public void testReadWritePackageRestrictionsSyncAfterAsync() {
+        final Settings settingsWrite = makeSettings();
+        final Settings settingsRead = makeSettings();
+        mHandler.clear();
+
+        // Initial state, distraction flags populated.
+        populateDistractionFlags(settingsWrite);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/true);
+
+        // 2 async writes of empty distraction flags.
+        populateDefaultSettings(settingsWrite);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+        settingsWrite.writePackageRestrictionsLPr(0, /*sync=*/false);
+
+        PriorityQueue<TestHandler.MsgInfo> messages = mHandler.getPendingMessages();
+        assertEquals(2, messages.size());
+        final Runnable asyncWrite1 = (Runnable) messages.poll().message.obj;
+        final Runnable asyncWrite2 = (Runnable) messages.poll().message.obj;
+
+        // First read should use read initial data (with flags).
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsRead);
+
+        // 1st write.
+        asyncWrite1.run();
+
+        // Second read should read updated data.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDefaultDistractionFlags(settingsRead);
+
+        // Sync write with flags - overrides all async writes.
+        populateDistractionFlags(settingsWrite);
+        settingsWrite.writeAllUsersPackageRestrictionsLPr(/*sync=*/true);
+
+        // Expect removeMessages call.
+        assertFalse(mHandler.hasMessages(WRITE_USER_PACKAGE_RESTRICTIONS));
+
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsRead);
+
+        // 2nd write.
+        asyncWrite2.run();
+
+        // Re-read and verify.
+        populateDefaultSettings(settingsRead);
+        settingsRead.readPackageRestrictionsLPr(0, mOrigFirstInstallTimes);
+        verifyDistractionFlags(settingsRead);
+    }
+
+    @Test
     public void testWriteReadUsesStaticLibraries() {
         final Settings settingsUnderTest = makeSettings();
         final PackageSetting ps1 = createPackageSetting(PACKAGE_NAME_1);
@@ -473,7 +667,7 @@ public class PackageManagerSettingsTests {
         ps2.setUsesStaticLibrariesVersions(new long[] { 34 });
         settingsUnderTest.mPackages.put(PACKAGE_NAME_2, ps2);
 
-        settingsUnderTest.writeLPr(computer);
+        settingsUnderTest.writeLPr(computer, /*sync=*/true);
 
         settingsUnderTest.mPackages.clear();
         settingsUnderTest.mDisabledSysPackages.clear();
@@ -538,7 +732,7 @@ public class PackageManagerSettingsTests {
         ps2.setUsesSdkLibrariesVersionsMajor(new long[] { 34 });
         settingsUnderTest.mPackages.put(PACKAGE_NAME_2, ps2);
 
-        settingsUnderTest.writeLPr(computer);
+        settingsUnderTest.writeLPr(computer, /*sync=*/true);
 
         settingsUnderTest.mPackages.clear();
         settingsUnderTest.mDisabledSysPackages.clear();
@@ -1548,7 +1742,8 @@ public class PackageManagerSettingsTests {
     private Settings makeSettings() {
         return new Settings(InstrumentationRegistry.getContext().getFilesDir(),
                 mRuntimePermissionsPersistence, mPermissionDataProvider,
-                mDomainVerificationManager, null, new PackageManagerTracedLock());
+                mDomainVerificationManager, mHandler,
+                new PackageManagerTracedLock());
     }
 
     private void verifyKeySetMetaData(Settings settings)
@@ -1610,4 +1805,5 @@ public class PackageManagerSettingsTests {
     private AndroidPackage mockAndroidPackage(PackageSetting pkgSetting) {
         return PackageImpl.forTesting(pkgSetting.getPackageName()).hideAsParsed().hideAsFinal();
     }
+
 }