Re: [2.6.9-rc4] USB && mass-storage && disconnect broken semantics

[Linas Vepstas <linas@austin.ibm.com>]

On Tue, Oct 12, 2004 at 12:24:44PM +0200, Oliver Neukum was heard to remark:
>  
> > With *nix, most data only gets written at unmount, so the only way this 
> > can "sanely" work is for mounts you haven't written to.  That case is of 
> 
> This is not a law of nature. You can mount sync as well. That, of course,
> sucks in terms of performance and wear. A reasonable compromise
> would be to do sync on close.
> Supermount did this years ago.

As a practical matter, sync-on-file-close should solve most 
of the practical problem of data corruption if the device is 
yanked before being onmounted.  However, when I read 
'man 2 open' there is no O_SYNC_ON_CLOSE.  

Similarly 'man 8 mount' doesn't list any option -o synconclose

It sure would be nice to be able to set up a sync-on-file-close
in the hotplug equiv of /etc/fstab for USB devices ... 

(When I think of sync-on-file-close, I don't mean 'global sync 
when the file is closed', I mean 'sync only that file's data and 
metadata only when the file is closed'.  That way, you don't slow 
down systems doing a lot of i/o on other, unrelated files)

--linas