From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3A9D1F779D; Tue, 12 Nov 2024 11:33:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731411211; cv=none; b=TNHNn1MPH3YiGsvzTpp2fHkd1vM52nSXALXdey4flebg31MQK4nkJePpeVJk7saP73tlyE1OtOy91+JHdUlig+5c3kgXP/TnGxFTie5IuXyXc6M8bo8jbrrA68KFxxqFjzdIjHFHTOOs3t6f4R4Kb3RTV9T+AUN92jvyx4Hfi/k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731411211; c=relaxed/simple; bh=oBgK9quMWhTuUk+yMkPXdYRqxgYSnvquji7TmTLYSk4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=LAFn+zXP9CtG2tPG0O5GeFaWjuEGOS7AiIgVw/BaBCefxlChcZLrAY0pCprcCdAMMPbI0sdrNMxmli2dMTh7w9Sjc1jDdp25gXEom+5zdEjPJV6jbkGBc/IP4o5VPr2SozCbVBkbWZYUSS+aklcUKDawlgLPqDh9ZGvpCuGWXgk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SeM3khei; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SeM3khei" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2A44C4CECD; Tue, 12 Nov 2024 11:33:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731411209; bh=oBgK9quMWhTuUk+yMkPXdYRqxgYSnvquji7TmTLYSk4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=SeM3kheiDwMHhOOg7ogBoIENMrBWZ7pi+xsSdGig2KvuN/w3YrjFwSjDmjtxH4rIU AgxpmTnLBwa/HWhDx3IQ6H9DZO43GGxGfK8HjCwYjCoapyi0SjBZVJEa5GjZ7HBpHl 1gbNsUKt2kUeY3sU7p8GczFvsJV8sPnaCQoEgD1RaBtOCi9gQsNBMYd8YH9Lrl2Se8 r/AMo437/J0PtTX5EOnUdI3cWwYIuXCIbtUBnHyDCHDYJx8N21AXKMoMWYtfo2TI+f UupqVACYGQH+Suu9Z80r5Njxhip4LWbRAnzsGLuW3CLkycRgkvJF4XmubfzCRekVYg H61lRubrXYUaw== Message-ID: <309c329dc3bab4ff8659fd7f1b48e7957aa32d80.camel@kernel.org> Subject: Re: [PATCH v3 0/2] fs: allow statmount to fetch the subtype and devname From: Jeff Layton To: Christian Brauner Cc: Karel Zak , Miklos Szeredi , Ian Kent , Josef Bacik , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Jan Kara Date: Tue, 12 Nov 2024 06:33:27 -0500 In-Reply-To: <20241112-vielzahl-grasen-51280e378f23@brauner> References: <20241107-statmount-v3-0-da5b9744c121@kernel.org> <20241111-ruhezeit-renovieren-d78a10af973f@brauner> <5418c22b64ac0d8d469d8f9725f1b7685e8daa1b.camel@kernel.org> <20241112-vielzahl-grasen-51280e378f23@brauner> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw 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Evolution 3.54.1 (3.54.1-1.fc41app1) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2024-11-12 at 10:42 +0100, Christian Brauner wrote: > On Mon, Nov 11, 2024 at 08:42:26AM -0500, Jeff Layton wrote: > > On Mon, 2024-11-11 at 10:17 +0100, Christian Brauner wrote: > > > On Thu, 07 Nov 2024 16:00:05 -0500, Jeff Layton wrote: > > > > Meta has some internal logging that scrapes /proc/self/mountinfo to= day. > > > > I'd like to convert it to use listmount()/statmount(), so we can do= a > > > > better job of monitoring with containers. We're missing some fields > > > > though. This patchset adds them. > > > >=20 > > > >=20 > > >=20 > > > I know Karel has been wanting this for libmount as well. Thanks for > > > doing this! It would be nice if you could also add some selftests! > > >=20 > >=20 > > (cc'ing Karel) > >=20 > > Thanks. We may need to tweak this a bit, based on Miklos' comments > > about how empty strings are handled now, but it shouldn't be too big a > > change. > >=20 > > I actually have a related question about libmount: glibc doesn't > > currently provide syscall wrappers for statmount() and listmount(). >=20 > I think it'll be a bit until glibc exposes those system calls because I > think they are special-purpose in a lot of ways. But also because glibc > usually takes a while to add new system call wrappers. >=20 > > Would it make sense to have libmount provide those? We could copy the >=20 > I think libmount may not necessarily provide direct syscall wrappers but > will expose new api functionality. This is at least what I gather from > all the discussions on util-linux. >=20 > > wrappers in tools/testing/selftests/filesystems/statmount/statmount.h > > to libmount.h. > >=20 > > It's error-prone and a pain to roll these yourself, and that would make >=20 > As with most system calls. >=20 > > things simpler until someone is ready to do something for glibc. > >=20 > > Another idea might be to start a new userland header file that is just > > a collection of static inline wrappers for syscalls that aren't > > packaged in glibc.e.g. pidfd_open also doesn't have glibc bindings, so > > we could add that there too. >=20 > Oh? What glibc version are you on? pidfd_open() et al should all have > glibc wrappers afaik. It just always takes a while: >=20 > > cat /usr/include/x86_64-linux-gnu/sys/pidfd.h | grep pidfd > extern int pidfd_open (__pid_t __pid, unsigned int __flags) __THR= OW; > extern int pidfd_getfd (int __pidfd, int __targetfd, > extern int pidfd_send_signal (int __pidfd, int __sig, siginfo_t *= __info, > extern pid_t pidfd_getpid (int __fd) __THROW; Ahh, I was trusting the manpage, which says: Note: glibc provides no wrapper for pidfd_open(), necessitating the use of syscall(2). It looks like recent glibc does have wrappers for this. --=20 Jeff Layton