linux-kernel - Re: [PATCH 0/6] overlayfs + casefolding

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Message-ID: <yp4whk37id7s4za6fv3ifvqjupo6ikylu34wvgd3ytbyu3uz2c@t7h3ncg6pwtz>
Date: Sun, 25 May 2025 14:27:23 -0400
From: Kent Overstreet <kent.overstreet@...ux.dev>
To: Amir Goldstein <amir73il@...il.com>
Cc: linux-fsdevel@...r.kernel.org, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-unionfs@...r.kernel.org, 
	Miklos Szeredi <miklos@...redi.hu>, Alexander Viro <viro@...iv.linux.org.uk>, 
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH 0/6] overlayfs + casefolding

On Sat, May 24, 2025 at 03:01:44PM +0200, Amir Goldstein wrote:
> On Fri, May 23, 2025 at 11:10 PM Kent Overstreet
> <kent.overstreet@...ux.dev> wrote:
> >
> > On Fri, May 23, 2025 at 10:30:16PM +0200, Amir Goldstein wrote:
> >
> > That makes fstests generic/631 pass.
> 
> Yes, that is not very surprising.
> I meant if you could help test that:
> 
> 1. mounting case folder upperdir/lowerdir fails
> 2. lookup a case folder subdir fails
> 3. lookup in a dir that was empty and became case folder while ovl was
> mounted fails
> 
> For me, I do not have any setup with case folding subtrees
> so testing those use cases would take me time and
> I think that you must have tested all those scenarios with your patch set?
> and maybe already have some fstests for them?

Unmount fauls after I test an overlayfs with a casefold subdir:

Testing an overlayfs on a casefold fs with non-casefolded dirs
Test using casefolded dir - should fail
overlayfs: failed to resolve '/mnt/casefold': -2
mount: /mnt/merged: special device overlay does not exist.
       dmesg(1) may have more information after failed mount system call.
Test using a dir with a casefold subdir - should mount
overlayfs: upperdir is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.
overlayfs: workdir is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.
ls: cannot access '/mnt/merged/dir/casefold': No such file or directory
umount: /mnt: target is busy.

https://evilpiepirate.org/git/ktest.git/commit/?id=47d1f2a04d79bc4cbc843f81e71eb7d821fb8384