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

[Josh Boyer]

On Thu, 2007-03-08 at 13:58 +0000, David Woodhouse wrote:
> On Thu, 2007-03-08 at 07:44 -0600, Josh Boyer wrote:
> > Wait... why?  Rejecting mount -o sync seems sane, but why can't O_SYNC
> > support be handled?  If users want to open their files like that and it
> > causes JFFS2 to flush a bunch of padding out, well they asked for it. 
> 
> Users ask for shared writable mmap too. That isn't a good idea either.
> 
> Contemplate what Linus always says about using 'volatile' vs. proper
> barriers. Now consider it for O_SYNC vs. fsync(). And factor in the fact
> that O_SYNC is going to be massively suboptimal if it causes syncs when
> they otherwise didn't need to happen.

Ok, good point.  You've convinced me.

josh