Android: sdcardfs: Change cache GID value

Change-Id: Ieb955dd26493da26a458bc20fbbe75bca32b094f
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 37193650

fs/sdcardfs/derived_perm.c

@@ -221,7 +221,7 @@ void fixup_lower_ownership(struct dentry *dentry, const char *name)
 		break;
 	case PERM_ANDROID_PACKAGE_CACHE:
 		if (info->d_uid != 0)
-			gid = multiuser_get_cache_gid(info->d_uid);
+			gid = multiuser_get_ext_cache_gid(info->d_uid);
 		else
 			gid = multiuser_get_uid(info->userid, uid);
 		break;

fs/sdcardfs/multiuser.h

@@ -23,6 +23,8 @@
 #define AID_APP_END          19999 /* last app user */
 #define AID_CACHE_GID_START  20000 /* start of gids for apps to mark cached data */
 #define AID_EXT_GID_START    30000 /* start of gids for apps to mark external data */
+#define AID_EXT_CACHE_GID_START 40000 /* start of gids for apps to mark external cached data */
+#define AID_EXT_CACHE_GID_END 49999   /* end of gids for apps to mark external cached data */
 #define AID_SHARED_GID_START 50000 /* start of gids for apps in each user to share */
 
 typedef uid_t userid_t;
@@ -33,9 +35,9 @@ static inline uid_t multiuser_get_uid(userid_t user_id, appid_t app_id)
 	return (user_id * AID_USER_OFFSET) + (app_id % AID_USER_OFFSET);
 }
 
-static inline gid_t multiuser_get_cache_gid(uid_t uid)
+static inline gid_t multiuser_get_ext_cache_gid(uid_t uid)
 {
-	return uid - AID_APP_START + AID_CACHE_GID_START;
+	return uid - AID_APP_START + AID_EXT_CACHE_GID_START;
 }
 
 static inline gid_t multiuser_get_ext_gid(uid_t uid)