From: Ian Kent <raven@themaw.net>
To: Sargun Dhillon <sargun@sargun.me>, Miklos Szeredi <mszeredi@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, linux-man@vger.kernel.org,
linux-security-module@vger.kernel.org,
Karel Zak <kzak@redhat.com>, David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <christian@brauner.io>,
Amir Goldstein <amir73il@gmail.com>
Subject: Re: [RFC PATCH 2/3] add statmnt(2) syscall
Date: Mon, 18 Sep 2023 07:36:39 +0800 [thread overview]
Message-ID: <39dc7081-fef3-007b-eee3-273bff549ecf@themaw.net> (raw)
In-Reply-To: <CAMp4zn-r5BV_T9VBPJf8Z-iG6=ziDEpCdmPgHRRXF78UoOjTjQ@mail.gmail.com>
On 18/9/23 02:18, Sargun Dhillon wrote:
> On Wed, Sep 13, 2023 at 9:25 AM Miklos Szeredi <mszeredi@redhat.com> wrote:
>> Add a way to query attributes of a single mount instead of having to parse
>> the complete /proc/$PID/mountinfo, which might be huge.
>>
>> Lookup the mount by the old (32bit) or new (64bit) mount ID. If a mount
>> needs to be queried based on path, then statx(2) can be used to first query
>> the mount ID belonging to the path.
>>
>> Design is based on a suggestion by Linus:
>>
>> "So I'd suggest something that is very much like "statfsat()", which gets
>> a buffer and a length, and returns an extended "struct statfs" *AND*
>> just a string description at the end."
>>
>> The interface closely mimics that of statx.
>>
>> Handle ASCII attributes by appending after the end of the structure (as per
>> above suggestion). Allow querying multiple string attributes with
>> individual offset/length for each. String are nul terminated (termination
>> isn't counted in length).
>>
>> Mount options are also delimited with nul characters. Unlike proc, special
>> characters are not quoted.
>>
> Thank you for writing this patch. I wish that this had existed the many times
> I've written parsers for mounts files in my life.
>
> What do you think about exposing the locked flags, a la what happens
> on propagation of mount across user namespaces?
Which flags do you mean?
If you mean shared, slave and I think there's a group id as well, etc.
then yes
they were available in the original fsinfo() implementation as they were
requested.
So, yes, it would be good to also include those too.
Ian
next prev parent reply other threads:[~2023-09-17 23:37 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 15:22 [RFC PATCH 0/3] quering mount attributes Miklos Szeredi
2023-09-13 15:22 ` [RFC PATCH 1/3] add unique mount ID Miklos Szeredi
2023-09-14 9:03 ` Christian Brauner
2023-09-14 9:30 ` Miklos Szeredi
2023-09-14 9:36 ` Christian Brauner
2023-09-14 9:43 ` Miklos Szeredi
2023-09-14 10:06 ` Christian Brauner
2023-09-15 1:31 ` Ian Kent
2023-09-13 15:22 ` [RFC PATCH 2/3] add statmnt(2) syscall Miklos Szeredi
2023-09-14 6:11 ` Amir Goldstein
2023-09-15 1:05 ` Ian Kent
2023-09-14 9:27 ` Christian Brauner
2023-09-14 10:13 ` Miklos Szeredi
2023-09-14 15:26 ` Christian Brauner
2023-09-15 8:56 ` Miklos Szeredi
2023-09-18 13:51 ` Christian Brauner
2023-09-18 14:14 ` Miklos Szeredi
2023-09-18 14:24 ` Christian Brauner
2023-09-18 14:32 ` Miklos Szeredi
2023-09-18 14:40 ` Christian Brauner
2023-09-18 14:51 ` Miklos Szeredi
2023-09-18 15:22 ` Christian Brauner
2023-09-18 15:39 ` Miklos Szeredi
2023-09-19 0:37 ` Matthew House
2023-09-19 8:02 ` Miklos Szeredi
2023-09-19 9:07 ` Christian Brauner
2023-09-19 10:51 ` Miklos Szeredi
2023-09-19 12:41 ` Christian Brauner
2023-09-19 12:59 ` Miklos Szeredi
2023-09-19 13:18 ` Christian Brauner
2023-09-19 21:28 ` Matthew House
2023-09-20 9:42 ` Miklos Szeredi
2023-09-20 13:26 ` Matthew House
2023-09-21 7:34 ` Miklos Szeredi
2023-09-26 13:48 ` Florian Weimer
2023-09-26 14:06 ` Miklos Szeredi
2023-09-26 14:19 ` Florian Weimer
2023-09-26 14:33 ` Miklos Szeredi
2023-09-26 14:39 ` Florian Weimer
2023-09-26 14:36 ` Christian Brauner
2023-09-26 14:13 ` Christian Brauner
2023-09-18 20:58 ` Andreas Dilger
2023-09-19 12:50 ` Christian Brauner
2023-09-20 0:33 ` Dave Chinner
2023-09-18 14:29 ` Jeff Layton
2023-09-18 14:35 ` Christian Brauner
2023-09-20 9:43 ` David Laight
2023-09-14 20:39 ` Paul Moore
2023-09-15 9:10 ` Miklos Szeredi
2023-09-17 18:18 ` Sargun Dhillon
2023-09-17 23:36 ` Ian Kent [this message]
2023-09-18 13:05 ` Christian Brauner
2023-09-25 12:57 ` Arnd Bergmann
2023-09-25 13:04 ` Christian Brauner
2023-09-25 13:13 ` Miklos Szeredi
2023-09-25 13:19 ` Christian Brauner
2023-09-25 13:20 ` Miklos Szeredi
2023-09-25 15:46 ` Arnd Bergmann
2023-09-26 10:05 ` Christian Brauner
2023-09-27 8:46 ` Miklos Szeredi
2023-09-13 15:22 ` [RFC PATCH 3/3] add listmnt(2) syscall Miklos Szeredi
2023-09-14 6:00 ` Amir Goldstein
2023-09-14 8:50 ` Miklos Szeredi
2023-09-14 10:01 ` Christian Brauner
2023-09-15 1:00 ` Ian Kent
2023-09-17 0:54 ` Matthew House
2023-09-17 14:32 ` Miklos Szeredi
2023-09-18 13:15 ` Christian Brauner
2023-09-19 16:47 ` Paul Moore
2023-09-28 10:07 ` Miklos Szeredi
2023-10-04 19:22 ` Paul Moore
2023-09-14 6:47 ` [RFC PATCH 0/3] quering mount attributes Amir Goldstein
2023-09-15 1:20 ` Ian Kent
2023-09-15 3:06 ` Amir Goldstein
2023-09-16 2:04 ` Ian Kent
2023-09-16 2:19 ` Ian Kent
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