Case-insensitive ext4

Posted Mar 27, 2019 19:08 UTC (Wed) by marcH (subscriber, #57642)
In reply to: Case-insensitive ext4 by clugstj
Parent article: Case-insensitive ext4

> I've yet to see a legitimate use case for putting this brain damage in the kernel

Without overly complicated code security researchers wouldn't have any work to do!

> Case-insensitivity would be set on a per-directory basis

Insanity has no limit. I was using the (otherwise pretty cool) Windows Subsystem for Linux. This is what happened:
https://github.com/vector-of-bool/vscode-cmake-tools/issu...

Because I was using the same project sometimes from WSL and sometimes from Windows, some directories *in the same project* were created case-sensitive and others not. Hilarity ensued.

Case-insensitive ext4

Posted Mar 27, 2019 19:47 UTC (Wed) by mathstuf (subscriber, #69389) [Link]

Well, CMake has "is case sensitive" logic baked in at compile time. Apple and Windows are "always case insensitive" and everything else is always case sensitive. I don't know what kinds of changes would be required in build tools to do this case insensitive comparisons. For example, this just doesn't work with ninja on Windows (I assume make has similar issues with the analogous ruleset):

rule copy
command = cp $in $out
build foo: copy in
build bar: copy FOO

saying that no rule makes FOO even though technically it will exist if you build foo. Basically, build tools that exist today need cases to match everywhere. And yes, ninja could figure this out right now, but if `dir/foo` and `dir/FOO` is used and `dir` is made by some rule during the build, its case sensitive flag can't be known at the start.

Case insensitivity in filesystems is broken. Conditional case sensitivity at a per-filesystem level means even ninja needs to add ioctl queries to figure that out, but `--one-file-system` is something that is at least enforceable. Per-directory flags which require magical "what will the flag on this directory be in the future" is even more broken.

I'd be surprised if "doesn't work in case insensitive ext4 directories" (nevermind an environment with a mix of case sensitive and insensitive directories) issues don't get closed as WONTFIX in many tools.