linux-kernel - Re: [PATCH] vfs: Add AT_EMPTY_PATH_NOCHECK as unchecked AT_EMPTY

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Date: Sun, 23 Jun 2024 08:59:40 +0800
From: Xi Ruoyao <xry111@...111.site>
To: Linus Torvalds <torvalds@...ux-foundation.org>, Mateusz Guzik
	 <mjguzik@...il.com>
Cc: Christian Brauner <brauner@...nel.org>, Alexander Viro
 <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>, Steven Rostedt
 <rostedt@...dmis.org>, Masami Hiramatsu <mhiramat@...nel.org>, Alejandro
 Colomar <alx@...nel.org>, Arnd Bergmann <arnd@...db.de>, Huacai Chen
 <chenhuacai@...ngson.cn>,  Xuerui Wang <kernel@...0n.name>, Jiaxun Yang
 <jiaxun.yang@...goat.com>, Icenowy Zheng <uwu@...nowy.me>, 
 linux-fsdevel@...r.kernel.org, linux-trace-kernel@...r.kernel.org, 
 linux-arch@...r.kernel.org, loongarch@...ts.linux.dev, 
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vfs: Add AT_EMPTY_PATH_NOCHECK as unchecked
 AT_EMPTY_PATH

On Sat, 2024-06-22 at 15:41 -0700, Linus Torvalds wrote:

> I do think that we should make AT_EMPTY_PATH with a NULL path
> "JustWork(tm)", because the stupid "look if the pathname is empty" is
> horrible.
> 
> But moving that check into getname() is *NOT* the right answer,
> because by the time you get to getname(), you have already lost.

Oops.  I'll try to get around of getname() too...

> So the short-cut in vfs_fstatat() to never get a pathname is
> disgusting - people should have used 'fstat()' - but it's _important_
> disgusting.

The problem is we don't have fstat() for LoongArch, and it'll be
unusable on all 32-bit arch after 2037.

And Arnd hates the idea adding fstat() for LoongArch because there would
be one more 32-bit arch broken in 2037.

Or should we just add something like "fstat_2037()"?

-- 
Xi Ruoyao <xry111@...111.site>
School of Aerospace Science and Technology, Xidian University