Re: [RFC] Null Namespaces
From: Andy Lutomirski <luto@kernel.org>
Date: 2026-06-24 23:20:23
Also in:
linux-arch, linux-fsdevel, lkml
On Wed, Jun 24, 2026 at 4:06 PM Andy Lutomirski [off-list ref] wrote:
On Wed, Jun 24, 2026 at 3:52 PM John Ericson [off-list ref] wrote:
quoted
- null current working directory: relative paths with traditional, non-`*at` system calls (and `*at` ones using `AT_FDCWD`) don't work.It's perfectly valid to cd to a directory that does not belong to one's namespace. We have fchdir. What's wrong with letting it continue working? Regardless of that, the current directory either needs to be a directory or to be nothing at all, and if we support the latter, we need to figure out what /proc will show.
Thinking about this more: I think that handling CWD might actually be a prerequisite for the series and has little to do with namespaces. Maybe try adding, as a standalone feature, the ability to have a null CWD. Define semantics and see what the implementation looks like. Then, if you add null namespaces, you could optionally make transitioning to a null namespace set a null CWD. Or those features could be orthogonal.