From: Jan Kara <jack@suse.cz>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Christian Brauner <brauner@kernel.org>,
Luis Henriques <lhenriques@suse.de>,
Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
Amir Goldstein <amir73il@gmail.com>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/3] ovl: fix the parsing of empty string mount parameters
Date: Mon, 11 Mar 2024 19:01:27 +0100 [thread overview]
Message-ID: <20240311180127.4qdr6ln2xf6vviu3@quack3> (raw)
In-Reply-To: <CAJfpegsn-jMY2J8Wd2Q9qmZFqxR6fAwZ4auoK+-uyxaK+F-0rw@mail.gmail.com>
On Mon 11-03-24 15:39:39, Miklos Szeredi wrote:
> On Mon, 11 Mar 2024 at 14:25, Christian Brauner <brauner@kernel.org> wrote:
>
> > Yeah, so with that I do agree. But have you read my reply to the other
> > thread? I'd like to hear your thoughs on that. The problem is that
> > mount(8) currently does:
> >
> > fsconfig(3, FSCONFIG_SET_FLAG, "usrjquota", NULL, 0) = -1 EINVAL (Invalid argument)
> >
> > for both -o usrjquota and -o usrjquota=
>
> For "-o usrjquota" this seems right.
>
> For "-o usrjquota=" it doesn't. Flags should never have that "=", so
> this seems buggy in more than one ways.
>
> > So we need a clear contract with userspace or the in-kernel solution
> > proposed here. I see the following options:
> >
> > (1) Userspace must know that mount options such as "usrjquota" that can
> > have no value must be specified as "usrjquota=" when passed to
> > mount(8). This in turn means we need to tell Karel to update
> > mount(8) to recognize this and infer from "usrjquota=" that it must
> > be passed as FSCONFIG_SET_STRING.
>
> Yes, this is what I'm thinking. Of course this only works if there
> are no backward compatibility issues, if "-o usrjquota" worked in the
> past and some systems out there relied on this, then this is not
> sufficient.
No, "-o usrjquota" never worked and I'm inclined to keep refusing this
variant as IMHO it is confusing.
> > In any case, we need to document what we want:
> >
> > https://github.com/brauner/man-pages-md/blob/main/fsconfig.md
>
> What's the plan with these? It would be good if "man fsconfig" would
> finally work.
Yes, merging these into official manpages would be nice.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2024-03-11 18:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-07 16:02 [PATCH v2 0/3] fs_parser: handle parameters that can be empty and don't have a value Luis Henriques
2024-03-07 16:02 ` [PATCH v2 1/3] fs_parser: add helper to define parameters with string and flag types Luis Henriques
2024-03-07 16:02 ` [PATCH v2 2/3] ext4: fix the parsing of empty string mount parameters Luis Henriques
2024-03-25 4:39 ` kernel test robot
2024-03-07 16:02 ` [PATCH v2 3/3] ovl: " Luis Henriques
2024-03-11 9:25 ` Miklos Szeredi
2024-03-11 10:34 ` Luis Henriques
2024-03-11 10:53 ` Miklos Szeredi
2024-03-11 13:23 ` Luis Henriques
2024-03-11 13:25 ` Christian Brauner
2024-03-11 14:39 ` Miklos Szeredi
2024-03-11 18:01 ` Jan Kara [this message]
2024-03-12 8:50 ` Christian Brauner
2024-03-12 8:47 ` Christian Brauner
2024-03-12 10:31 ` Luis Henriques
2024-03-22 14:22 ` Christian Brauner
2024-03-22 15:17 ` Luis Henriques
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