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Message-ID: <fd19d9585b29952fcd727c1a6c47289f66ab96b7.camel@kernel.org>
Subject: Re: [PATCH 1/2] fs/ceph/debugfs: make all files world-readable
From:   Jeff Layton <jlayton@kernel.org>
To:     Ilya Dryomov <idryomov@gmail.com>,
        Max Kellermann <max.kellermann@ionos.com>
Cc:     Xiubo Li <xiubli@redhat.com>, ceph-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Lorenzo Bianconi <lorenzo@kernel.org>
Date:   Mon, 25 Sep 2023 07:29:43 -0400
In-Reply-To: <CAOi1vP80WvQhuXgzhvzupQP=4K2ckgu_WpUCtUSy5M+QdDycqw@mail.gmail.com>
References: <20230922062558.1739642-1-max.kellermann@ionos.com>
         <CAOi1vP80WvQhuXgzhvzupQP=4K2ckgu_WpUCtUSy5M+QdDycqw@mail.gmail.com>
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On Mon, 2023-09-25 at 12:41 +0200, Ilya Dryomov wrote:
> On Fri, Sep 22, 2023 at 8:26=E2=80=AFAM Max Kellermann <max.kellermann@io=
nos.com> wrote:
> >=20
> > I'd like to be able to run metrics collector processes without special
> > privileges
>=20
> Hi Max,
>=20
> A word of caution about building metrics collectors based on debugfs
> output: there are no stability guarantees.  While the format won't be
> changed just for the sake of change of course, expect zero effort to
> preserve backwards compatibility.
>=20
> The latency metrics in particular are sent to the MDS in binary form
> and are intended to be consumed through commands like "ceph fs top".
> debugfs stuff is there just for an occasional sneak peek (apart from
> actual debugging).
>=20

FWIW, I wish we had gone with netlink for this functionality instead of
a seqfile. Lorenzo has been working with netlink for some similar
functionality with nfsd[1], and it's much nicer for this sort of thing.

[1]: https://lore.kernel.org/linux-nfs/ZQTM6l7NrsVHFoR5@lore-desk/T/#t

--=20
Jeff Layton <jlayton@kernel.org>