JFFS2 as transactional FS (in other words: how to be sure that data have been writtent correctly from userspace)

[David Woodhouse]

On Thu, 2007-03-08 at 14:12 +0100, Jörn Engel wrote:
> Then you have your bug report.  Ignoring those was ok in 2001, but with
> wbuf I would at least expect JFFS2 to return an error.

Not quite, because that's not what he was trying. He said he was using
fsync().

I would hope that JFFS2 doesn't _have_ to return an error -- the VFS
should do so if the filesystem doesn't support a given option. That
doesn't seem to be the case though, so I agree that we should make JFFS2
check for those two flags and refuse the operation (mount/open) for
write-buffered flash.

> One option for implementing this would be to do the write, call schedule
> to let other processes write something, then check whether the buffer
> has been flushed out by other processes.  Or do some GC to fill the
> buffer with useful data.  Anything but padding it. 

Better just to say 'no', I think :)

-- 
dwmw2