The unexpected power loss or system crash can result in data inconsistency upon updating a persistent data structure. Most existing file systems use some consistency techniques such as write-ahead logging, copy-on-write to avoid this situation. These mechanisms, however, introduce a significant overhead, and fail to adapt to the diversity of directory and heterogeneity of data reliability demands. Existing file-adaptive journaling technique is required to modify legacy applications. Therefore, a directory-adaptive journaling mode selective mechanism for Android systems was proposed to choose different journaling modes with strong or weak consistency guarantees in terms of different directories reliability demands. This mechanism is transparent to developers, and also matches the feature of Android systems, hence, it greatly reduces the consistency guarantee overhead without sacrifice of reliability. The experimental results show that modified file system can identify directories in which a file resides, meanwhile, choose reasonable pre-defined journaling mode.