From: Ian Kent <raven@themaw.net>
To: Amir Goldstein <amir73il@gmail.com>,
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>
Subject: Re: [RFC PATCH 0/3] quering mount attributes
Date: Fri, 15 Sep 2023 09:20:38 +0800 [thread overview]
Message-ID: <904a8d17-b6df-e294-fcf6-6f95459e1ffa@themaw.net> (raw)
In-Reply-To: <CAOQ4uxiuc0VNVaF98SE0axE3Mw6wMJJ1t36cmbcM5vwYLqtWSw@mail.gmail.com>
On 14/9/23 14:47, Amir Goldstein wrote:
> On Wed, Sep 13, 2023 at 6:22 PM Miklos Szeredi <mszeredi@redhat.com> wrote:
>> Implement the mount querying syscalls agreed on at LSF/MM 2023. This is an
>> RFC with just x86_64 syscalls.
>>
>> Excepting notification this should allow full replacement for
>> parsing /proc/self/mountinfo.
> Since you mentioned notifications, I will add that the plan discussed
> in LFSMM was, once we have an API to query mount stats and children,
> implement fanotify events for:
> mount [mntuid] was un/mounted at [parent mntuid],[dirfid+name]
>
> As with other fanotify events, the self mntuid and dirfid+name
> information can be omitted and without it, multiple un/mount events
> from the same parent mntuid will be merged, allowing userspace
> to listmnt() periodically only mntuid whose child mounts have changed,
> with little risk of event queue overflow.
>
> The possible monitoring scopes would be the entire mount namespace
> of the monitoring program or watching a single mount for change in
> its children mounts. The latter is similar to inotify directory children watch,
> where the watches needs to be set recursively, with all the weight on
> userspace to avoid races.
It's been my belief that the existing notification mechanisms don't
quite fully satisfy the needs of users of these calls (aka. the need
I found when implementing David's original calls into systemd).
Specifically the ability to process a batch of notifications at once.
Admittedly the notifications mechanism that David originally implemented
didn't fully implement what I found I needed but it did provide for a
settable queue length and getting a batch of notifications at a time.
Am I mistaken in my belief?
Don't misunderstand me, it would be great for the existing notification
mechanisms to support these system calls, I just have a specific use case
in mind that I think is important, at least to me.
Ian
next prev parent reply other threads:[~2023-09-15 1:20 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
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 [this message]
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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