sys_fsync() question

["Hao-Ran Liu" <josephl@xxxxxxxxxxxxxx>]

Dear All,

 

I read kernel 2.6.9 page cache code and have some questions.

Please help..

 

1. Is the call to filemap_fdatawrite() in sys_fsync() redundant? Since

sys_fsync() will call file->f_op->fsync(), and, both filemap_fdatawrite()and

file->f_op->fsync() (ext2, for example) eventually call do_writepages()

function.

 

2. for ext2, the purpose of sync_mapping_buffers() is to write out all indirect blocks of an address_space, which is called by ext2_sync_file().

How do these buffers got synced when a user program called sys_sync()? I don't find any call to ext2_sync_file() by sys_sync(). If

sync_mapping_buffers() is not needed for sys_sync(), then this should apply for ext2_sync_file(), too?

 

 

Thanks,

Hao-Ran Liu