Fail upgrades that change storage devices.

Now that we live in an FBE world, we need the user to be involved
with every package move to ensure that CE storage is unlocked.  This
means that a package upgrade session that would require moving an
app between storage devices cannot be satisfied.

Bug: 27147501
Change-Id: I274d85cbed727d9185178b77bfc6cef196df17f5

core/java/com/android/internal/content/PackageHelper.java

@@ -37,7 +37,6 @@ import android.os.storage.VolumeInfo;
 import android.provider.Settings;
 import android.util.ArraySet;
 import android.util.Log;
-import android.util.Slog;
 
 import libcore.io.IoUtils;
 
@@ -46,6 +45,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Collections;
+import java.util.Objects;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 import java.util.zip.ZipOutputStream;
@@ -383,23 +383,31 @@ public class PackageHelper {
             installLocation = PackageInfo.INSTALL_LOCATION_INTERNAL_ONLY;
         }
 
-        // If app expresses strong desire for internal space, honor it
+        // If app expresses strong desire for internal storage, honor it
         if (!forceAllowOnExternal
                 && installLocation == PackageInfo.INSTALL_LOCATION_INTERNAL_ONLY) {
+            if (existingInfo != null && !Objects.equals(existingInfo.volumeUuid,
+                    StorageManager.UUID_PRIVATE_INTERNAL)) {
+                throw new IOException("Cannot automatically move " + packageName + " from "
+                        + existingInfo.volumeUuid + " to internal storage");
+            }
             if (fitsOnInternal) {
-                return null;
+                return StorageManager.UUID_PRIVATE_INTERNAL;
             } else {
                 throw new IOException("Requested internal only, but not enough space");
             }
         }
 
-        // If app already exists somewhere, prefer to stay on that volume
+        // If app already exists somewhere, we must stay on that volume
         if (existingInfo != null) {
-            if (existingInfo.volumeUuid == null && fitsOnInternal) {
-                return null;
-            }
-            if (allCandidates.contains(existingInfo.volumeUuid)) {
+            if (Objects.equals(existingInfo.volumeUuid, StorageManager.UUID_PRIVATE_INTERNAL)
+                    && fitsOnInternal) {
+                return StorageManager.UUID_PRIVATE_INTERNAL;
+            } else if (allCandidates.contains(existingInfo.volumeUuid)) {
                 return existingInfo.volumeUuid;
+            } else {
+                throw new IOException("Not enough space on existing volume "
+                        + existingInfo.volumeUuid + " for " + packageName + " upgrade");
             }
         }
 
@@ -408,7 +416,7 @@ public class PackageHelper {
         if (bestCandidate != null) {
             return bestCandidate.fsUuid;
         } else if (fitsOnInternal) {
-            return null;
+            return StorageManager.UUID_PRIVATE_INTERNAL;
         } else {
             throw new IOException("No special requests, but no room anywhere");
         }