Enable 9P client caching support

configname: CONFIG_9P_FSCACHE

Linux Kernel Configuration
└─>File systems
└─>Network File Systems
└─>Enable 9P client caching support
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
Choose Y here to enable persistent, read-only local
caching support for 9p clients using FS-Cache