Re: [PATCH] shmem: support xattr gnu.* namespace for the Hurd

[Baolin Wang <baolin.wang@linux.alibaba.com>]

CC fs maillist

On 5/16/26 3:58 AM, Janneke Nieuwenhuizen wrote:
>  From d8291d06b67db045033664fb440f59001d7755a1 Mon Sep 17 00:00:00 2001
> From: Janneke Nieuwenhuizen <janneke@gnu.org>
> Date: Fri, 15 May 2026 10:12:30 +0200
> Subject: [PATCH] shmem: support xattr gnu.* namespace for the Hurd
> 
> The Hurd gained[0] support for moving the translator and author
> fields out of the inode and into the "gnu.*" xattr namespace.
> 
> In anticipation of that, an xattr INDEX was reserved[1].  The Hurd has
> now been brought into compliance[2] with that, and so has ext4[3].
> 
> This patch adds support for reading and writing such attributes from
> a Linux tmpfs; you can now do something like
> 
>      mkdir -p hurd-root
>      mount -t tmpfs -o size=2M tmpfs hurd-root
>      mkdir -p hurd-root/servers/socket
>      touch hurd-root/servers/socket/1
>      setfattr --name=gnu.translator --value='"/hurd/pflocal\0"' \
>          hurd-root/servers/socket/1
>      getfattr --name=gnu.translator hurd-root/servers/socket/1
>      # file: 1
>      gnu.translator="/hurd/pflocal"
> 
> to setup a pipe translator, which is being used to create an
> initial file-system image for the Hurd from GNU Guix[4].

Please add your Singed-off-by tag.

> [0] https://summerofcode.withgoogle.com/projects/#5869799859027968
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3980bd3b406addb327d858aebd19e229ea340b9a
> [2] https://git.savannah.gnu.org/cgit/hurd/hurd.git/commit/?id=a04c7bf83172faa7cb080fbe3b6c04a8415ca645
> [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=88ee9d571b6d8ed345f877e05f685814412e359b
> [4] https://codeberg.org/guix/guix/pulls/8632
> ---
>   mm/shmem.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 3b5dc21b323c..5d60aa4dba92 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -15,6 +15,7 @@
>    * Extended attribute support for tmpfs:
>    * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
>    * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
> + * Copyright (C) 2026 Janneke Nieuwenhuizen <janneke@gnu.org>
>    *
>    * tiny-shmem:
>    * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
> @@ -4371,10 +4372,17 @@ static const struct xattr_handler shmem_user_xattr_handler = {
>   	.set = shmem_xattr_handler_set,
>   };
>   
> +static const struct xattr_handler shmem_hurd_xattr_handler = {
> +	.prefix = XATTR_HURD_PREFIX,
> +	.get = shmem_xattr_handler_get,
> +	.set = shmem_xattr_handler_set,
> +};
> +
>   static const struct xattr_handler * const shmem_xattr_handlers[] = {
>   	&shmem_security_xattr_handler,
>   	&shmem_trusted_xattr_handler,
>   	&shmem_user_xattr_handler,
> +	&shmem_hurd_xattr_handler,
>   	NULL
>   };
>