The purpose of yaffs_hold_space() is to support the write_begin VFS method. write_begin asks the file system to commit enough space to do the actual write in write_end. Strictly speaking this should really be handled with counter of committed space that is incremented on every write_begin and decremented on every write_end. However, it is workable to just not expect there to be more than n writes in progress at a time. n=20 seems rather conservative. -- Charles On Thu, Jul 30, 2015 at 3:04 PM, chenjie wrote: > > Hi: > why the yaffs_hold_space reserved 20 chunk? > return (n_free_chunks > 20) ? 1 : 0; > > > >