Re: ext3fs: umount+sync not enough to guarantee metadata-on-disk

Stephen C. Tweedie
2007-06-07T17:10:08Z

Hi,

On Thu, 2007-06-07 at 12:01 -0400, Mark Lord wrote:

> >> mount /var/lib/mythtv -oremount,ro
> >> sync
> >> umount /var/lib/mythtv
> >
> > Did this succeed? If the application is still truncating that file, the
> > umount should have failed.
>
> Actually, what I expect to happen is for the remount,ro
> to block until the file deletion completes. But it doesn't.

No -- all that the remount,ro sees is that there's a fd still open for
write. It has no idea if or when that fd is going to get closed, so it
should fail. Returning -EBUSY is the only thing it _can_ do: waiting
for the fs to be remountable might wait forever.

So the fs is still writable after that point.

--Stephen