On Thu, May 21, 2026 at 4:54 PM Christian Brauner [off-list ref] wrote:

On Thu, Apr 16, 2026 at 03:07:12PM +0200, Christian Brauner wrote:

quoted

On Sat, 28 Mar 2026 23:22:21 +0600, Dorjoy Chowdhury wrote:

quoted

I came upon this "Ability to only open regular files" uapi feature suggestion
from https://uapi-group.org/kernel-features/#ability-to-only-open-regular-files
and thought it would be something I could do as a first patch and get to
know the kernel code a bit better.

The following filesystems have been tested by building and booting the kernel
x86 bzImage in a Fedora 43 VM in QEMU. I have tested with OPENAT2_REGULAR that
regular files can be successfully opened and non-regular files (directory, fifo etc)
return -EFTYPE.
- btrfs
- NFS (loopback)
- SMB (loopback)

[...]

- I've added an explanation why OPENAT2_REGULAR is only needed for some
  ->atomic_open() implementers but not others. What I don't like is that
  we need all that custom handling in there but it's managable.

- I dropped the topmost style conversions. They really don't belong
  there and if we switch to something better we should use (1 << <nr>).

- I split the EFTYPE errno introduction into a separate patch.

So I've massaged this series a bit in that I moved OPENAT2_REGULAR into
the upper 64-bit and internally use a __O_REGULAR bit. After having
thought about it makes a lot more sense to move the openat2() only
features into the upper 32-bit for the uapi space. I also ported the
selftests to the TEST* framework to fit with Aleksa's recent rework.

Thanks for fixing up!

Regards,
Dorjoy