On Sun, Nov 6, 2016 at 8:14 PM, Konstantin Khlebnikov <koct9i@xxxxxxxxx> wrote: > On Wed, Oct 26, 2016 at 2:12 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: >> On Tue, Oct 25, 2016 at 1:57 PM, Raphael Hertzog <hertzog@xxxxxxxxxx> wrote: >> >>> Do you plan to make it the default in the future when it has been >>> available for a while? >>> >>> Barring any regression introduced by your patch, it seems that the feature >>> is best available by default since it allows legitimate operations to >>> succeed that are otherwise refused. I understand that it makes it >>> impossible to mount the overlay filesystem with an older kernel but is >>> that problem more widespread than the one we're fixing here? On my side, >>> overlayfs is only used in scenarios where the kernel is always the same >>> (or newer compared to what created the initial filesystem). >> >> I think it would be safe to make it the default if upperdir is empty. >> Nonempty implies that it was created with old kernel (or it was >> crafted by hand). But there should be a way to explicitly turn it >> off; either because of the need for backward compatibility or because >> the old format is simply easier to work with for humans. >> >> How about: >> >> - If upper is nonempty, then leave redirect feature alone except when >> mount option "-oredirect=on" is used to force enabling it. >> - If upper is empty, then enable redirect feature except when mount >> option "-oredirect=off" is used to force disabling it. > > I don't like this empty-nonempty upper logic. > > I think this feature should be off by default and be enabled > explicitly in mount option. > Available features could be listed in sysfs /sys/fs/overlay/..., like ext4 does. > > Overlayfs mounting anyway is complicated operation. > User must know a lot about it and provide persistent state for each mount: > list layers in correct order, work and uppder directory on the same disk, etc. > Enabled features is a part of this state. > > Probably this could be solved in userspace tool "mount.overlay" - it could load > features and layers from config file or xattr and set required mount > options automatically. It seems there are some conflicting opinions here. I have mine too, but I'll let this simmer and concentrate on actual features for now. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
