On Sat, Dec 8, 2018 at 1:58 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> I'm hoping you are at least doing it per-directory. That makes at
> least the "oh, the whole filesystem needs to do this wrong" issue a
> bit less bad.
So for example, if you do it per-directory, the rules could be something like:
- new directories (ie "mkdir()") inherit the icase/folding semantics
of the parent directory
- empty directories can have their case/folding rules changed with
some well-defined interface
and even from just those simple rules, now some icase behavior could
be useful to testing.
Not just filesystem testing (although that would be a thing - thing
fsstress), but for doing app development in a test directory.
Apps like git (and GNU fileutils) could use it for having test suites
for FAT etc filesystems.
And cross-platform apps could use it as a "I want to check that I do
the right thing" if you do development on Linux, but might have a
portable app for other platforms.
If the whole filesystem is that way, nobody is going to do it. Sure,
they could do it on a FAT filesystem using a USB disk, but nobody
really does that. But if you can troivially just run your tests in a
test subdirectory, it's another thing entirely.
So this is the kind of thing I mean when I think icase behavior for a
major Linux filesystem should have a real _design_. It's really quite
fundamentally different from the "oh, I need FAT to be icase" hack
that we have now.
(We might also be able to make the dcache better at handling
well-defined icase/folding rules, as opposed to the current "just give
up, let the filesystem hash it" behavior).
Linus
