On Tue, May 20, 2025 at 4:44 PM Kent Overstreet <kent.overstreet@xxxxxxxxx> wrote: > > On Tue, May 20, 2025 at 04:33:14PM +0200, Amir Goldstein wrote: > > On Tue, May 20, 2025 at 4:12 PM Kent Overstreet > > > Amir, you've got two widely used filesystem features that conflict and > > > can't be used on the same filesystem. > > > > > > That's _broken_. > > > > Correct. > > > > I am saying that IMO a smaller impact (and less user friendly) fix is more > > appropriate way to deal with this problem. > > Less user friendly is an understatement. > > Obscure errors that only get reported via overloaded standard error > codes is a massive problem today, for _developers_ - have you never had > a day of swearing over trying to track down where in a massive subsystem > an -EINVAL is coming from? > > It's even worse for end users that don't know to check the dmesg log. > > And I support my code, so these would turn into bug reports coming > across my desk - no thanks; I already get enough weird shit from other > subsystems that I have to look at and at least triage. > > > > Users hate partitioning just for separate /boot and /home, having to > > > partition for different applications is horrible. And since overlay fs > > > is used under the hood by docker, and casefolding is used under the hood > > > for running Windows applications, this isn't something people can > > > predict in advance. > > > > Right, I am not expecting users to partition by application, > > but my question was this: > > > > When is overlayfs created over a subtree that is only partially case-folded? > > > > Obviously, docker would create overlayfs on parts of the fs > > and smbd/cygwin could create a case folder subtree on another > > part of the fs. > > I just don't see a common use case when these sections overlap. > > Today, you cannot user docker and casefolding on _different parts of_ > the same filesystem. > > So yees, today users do have to partition by application, or only use > one feature or the other. > Didn't say there was no problem. Argued that your fix is a big gun and not worth the added complexity. Let's see what Miklos thinks. > This isn't about allowing casefolding and overlayfs to fix on the same > subtree, that would be a bigger project. > > > Perhaps I am wrong (please present real world use cases), > > but my claim is that this case is not common enough and therefore, > > a suboptimal EIO error from lookup is good enough to prevert crossing > > over into the case folded zone by mistake, just as EIO on lookup is > > enough to deal with the unsupported use case of modifying > > overlayfs underlying layers with overlay is mounted. > > > > BTW, it is not enough to claim that there is no case folding for the > > entire subtree to allow the mount. > > For overlayfs to allow d_hash()/d_compare() fs must claim that > > these implementations are the default implementation in all subtree > > or at least that all layers share the same implementation. > Nevermind. Misread patch 6. Thanks, Amir.
