On Tue, 2025-09-09 at 18:06 +0200, Cedric Blancher wrote: > On Tue, 10 Jun 2025 at 07:34, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > > > On Mon, Jun 09, 2025 at 10:16:24AM -0400, Chuck Lever wrote: > > > > Date: Wed May 21 16:50:46 2008 +1000 > > > > > > > > dcache: Add case-insensitive support d_ci_add() routine > > > > > > My memory must be quite faulty then. I remember there being significant > > > controversy at the Park City LSF around some patches adding support for > > > case insensitivity. But so be it -- I must not have paid terribly close > > > attention due to lack of oxygen. > > > > Well, that is when the ext4 CI code landed, which added the unicode > > normalization, and with that another whole bunch of issues. > > Well, no one likes the Han unification, and the mess the Unicode > consortium made from that, > But the Chinese are working on a replacement standard for Unicode, so > that will be a lot of FUN =:-) > > > > > That being said no one ever intended any of these to be exported over > > > > NFS, and I also question the sanity of anyone wanting to use case > > > > insensitive file systems over NFS. > > > > > > My sense is that case insensitivity for NFS exports is for Windows-based > > > clients > > > > I still question the sanity of anyone using a Windows NFS client in > > general, but even more so on a case insensitive file system :) > > Well, if you want one and the same homedir on both Linux and Windows, > then you have the option between the SMB/CIFS and the Windows NFSv4.2 > driver (I'm not counting the Windows NFSv3 driver due lack of ACL > support). > Both, as of September 2025, work fine for us for production usage. > > > > Does it, for example, make sense for NFSD to query the file system > > > on its case sensitivity when it prepares an NFSv3 PATHCONF response? > > > Or perhaps only for NFSv4, since NFSv4 pretends to have some recognition > > > of internationalized file names? > > > > Linus hates pathconf any anything like it with passion. Altough we > > basically got it now with statx by tacking it onto a fast path > > interface instead, which he now obviously also hates. But yes, nfsd > > not beeing able to query lots of attributes, including actual important > > ones is largely due to the lack of proper VFS interfaces. > > What does Linus recommend as an alternative to pathconf()? > > Also, AGAIN the question: > Due lack of a VFS interface and the urgend use case of needing to > export a case-insensitive filesystem via NFSv4.x, could we please get > two /etc/exports options, one setting the case-insensitive boolean > (true, false, get-default-from-fs) and one for case-preserving (true, > false, get-default-from-fs)? > > So far LInux nfsd does the WRONG thing here, and exports even > case-insensitive filesystems as case-sensitive. The Windows NFSv4.1 > server does it correctly. > > Ced I think you don't want an export option for this. It sounds like what we really need is a mechanism to determine whether the inode the client is doing a GETATTR against lies on a case- insensitive mount. Is there a way to detect that in the kernel? -- Jeff Layton <jlayton@xxxxxxxxxx>
