Re: What trigge fsync of file on last close of the open inode?

[Steve French <smfltc@us.ibm.com>]

Dave Kleikamp wrote:
>> Someone had reported a problem with a writepages call coming in on with 
>> no open files (so presumably the file was closed, with dirty pages not 
>> written).
>>     
>
> This is normal behavior for most file systems.  I thought cifs protected
> this by flushing dirty data in cifs_close.  I don't think any data
> should be dirtied after cifs_close is called (on the last open file
> handle).
>   
I found it ...

cifs exports flush, filp_close calls flush (before calling close)

cifs_flush calls filemap_fdatawrite

May be a case in which filemap_fdatawrite returns before the write(s) is 
sent to the vfs and write races with close (although cifs will defer a 
file close if a write is pending on that handle)?