On Sat, 14 Oct 2023 at 17:32, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > On Sat, Oct 14, 2023 at 5:09 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > > > On Sat, 14 Oct 2023 at 10:24, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > > > Being extra nice and displaying "a\,b" and "a\:b" for new users that > > > used new mount api explicitly to pass "a,b" and "a:b" is possible, but > > > it is not a 6.5 regression fix, so we can take the time to decide if we > > > want to do that or not. > > > > > > OK? > > > > Yeah, I'm mostly convinced by your arguments. > > > > The other issue that has to be decided pretty quickly is whether to > > leave the append mode (starting lowerdir with ':') or remove it now > > and replace it in the next cycle with a mode that doesn't play games > > with separators (i.e. adding layers one at a time). > > > > The only argument I can see for the current append is that it's > > possible to add multiple layers at once, but it's also redundant once > > we add the one-by-one append mode and I'm not convinced that it's > > worth the complexity and the mess with having to escape separators. > > > > What do you think? > > I think that we can leave the string-append mode, but disallow ':' and '\' > within an appended string, so we only support adding lowerdirs one at > a time and no support for special chars in file name, so escaping is moot. > > This way, we do not complicate things and leave the functionality intact. > Sure, it's going to be redundant once we add support for > FSCONFIG_SET_PATH*, but the added code to strip the ":" or "::" > prefix for FSCONFIG_SET_STRING is not really complicated. > > I can add this patch if you agree (without all the possible code cleanup). So what I figured is that a separate key for the append interface is better, otherwise data only and plain lower layers can't be differentiated. So my PoC is using "lowerdir+" and "datadir+" for this. I think this might be a good convention going forward if any other filesystem needs such append mode options. If you can code this up quickly, that's good. I can have a go at it on Monday, but my PoC patch needs splitting up and so it's not ready for 6.6. Thanks, Miklos
