Re: [PATCH v6 0/4] OPENAT2_REGULAR flag support for openat2

[Christian Brauner <brauner@kernel.org>]

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

---

Applied to the vfs-7.2.openat.regular branch of the vfs/vfs.git tree.
Patches in the vfs-7.2.openat.regular branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: master

[1/4] openat2: new OPENAT2_REGULAR flag support
      https://git.kernel.org/vfs/vfs/c/0b649c4d70f7
[2/4] kselftest/openat2: test for OPENAT2_REGULAR flag
      https://git.kernel.org/vfs/vfs/c/d7dc36df8fa7
[3/4] sparc/fcntl.h: convert O_* flag macros from hex to octal
      (dropped)
[4/4] mips/fcntl.h: convert O_* flag macros from hex to octal
      (dropped)