On Mon, Jun 16, 2025 at 2:28 PM Kent Overstreet <kent.overstreet@xxxxxxxxx> wrote: > > On Mon, Jun 16, 2025 at 10:06:32AM +0200, Amir Goldstein wrote: > > On Sun, Jun 15, 2025 at 9:20 PM Kent Overstreet > > <kent.overstreet@xxxxxxxxx> wrote: > > > > > > On Mon, Jun 02, 2025 at 07:17:02PM +0200, Amir Goldstein wrote: > > > > Case folding is often applied to subtrees and not on an entire > > > > filesystem. > > > > > > > > Disallowing layers from filesystems that support case folding is over > > > > limiting. > > > > > > > > Replace the rule that case-folding capable are not allowed as layers > > > > with a rule that case folded directories are not allowed in a merged > > > > directory stack. > > > > > > > > Should case folding be enabled on an underlying directory while > > > > overlayfs is mounted the outcome is generally undefined. > > > > > > > > Specifically in ovl_lookup(), we check the base underlying directory > > > > and fail with -ESTALE and write a warning to kmsg if an underlying > > > > directory case folding is enabled. > > > > > > > > Suggested-by: Kent Overstreet <kent.overstreet@xxxxxxxxx> > > > > Link: https://lore.kernel.org/linux-fsdevel/20250520051600.1903319-1-kent.overstreet@xxxxxxxxx/ > > > > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > > > > --- > > > > > > > > Miklos, > > > > > > > > This is my solution to Kent's request to allow overlayfs mount on > > > > bcachefs subtrees that do not have casefolding enabled, while other > > > > subtrees do have casefolding enabled. > > > > > > > > I have written a test to cover the change of behavior [1]. > > > > This test does not run on old kernel's where the mount always fails > > > > with casefold capable layers. > > > > > > > > Let me know what you think. > > > > > > > > Kent, > > > > > > > > I have tested this on ext4. > > > > Please test on bcachefs. > > > > > > Where are we at with getting this in? I've got users who keep asking, so > > > hoping we can get it backported to 6.15 > > > > I'm planning to queue this for 6.17, but hoping to get an ACK from Miklos first. > > This is a regression for bcachefs users, why isn't it being considered for > 6.16? This is an ovl behavior change on fs like ext4 regardless of bcachefs. This change of behavior, which is desired for your users, could expose other users to other regressions. I am not sure that it is a clear cut candidate for 6.16, but I also don't feel very strongly this way or the other, so I will let Miklos decide. In any case, even if the change gets merged in 6.17, after the change was exposed to the world for a bit and no regressions reported, I have no objections backporting it to older kernels. Thanks, Amir.
