linux-ext4 - Re: [PATCH v7 05/18] fsnotify: introduce pre-content permission events

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Message-ID: <CAHk-=wg02AubUBZ5DxLra7b5w2+hxawdipPqEHemg=Lf8b1TDA@mail.gmail.com>
Date: Tue, 12 Nov 2024 16:23:28 -0800
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Al Viro <viro@...iv.linux.org.uk>
Cc: Amir Goldstein <amir73il@...il.com>, Josef Bacik <josef@...icpanda.com>, kernel-team@...com, 
	linux-fsdevel@...r.kernel.org, jack@...e.cz, brauner@...nel.org, 
	linux-xfs@...r.kernel.org, linux-btrfs@...r.kernel.org, linux-mm@...ck.org, 
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH v7 05/18] fsnotify: introduce pre-content permission events

On Tue, 12 Nov 2024 at 16:12, Al Viro <viro@...iv.linux.org.uk> wrote:
>
> Ugh...  Actually, I would rather mask that on fcntl side (and possibly
> moved FMODE_RANDOM/FMODE_NOREUSE over there as well).

Yeah, that's probably cleaner. I was thinking the bitfield would be a
simpler solution, but we already mask writes to specific bits on the
fcntl side for other reasons *anyway*, so we might as well mask reads
too, and just not expose any kernel-internal bits to user space.

> Would make for simpler rules for locking - ->f_mode would be never
> changed past open, ->f_flags would have all changes under ->f_lock.

Yeah, sounds sane.

That said, just looking at which bits are used in f_flags is a major
PITA. About half the definitions use octal, with the other half using
hex. Lovely.

So I'd rather not touch that mess until we have to.

                Linus