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From:   Aleksandr Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Date:   Wed, 7 Jun 2023 17:24:50 +0200
Message-ID: <CAEivzxejMtctdEF2BHMBM5fU-5-Ps7Qt25_yLBTzDayUVNoErg@mail.gmail.com>
Subject: Re: [PATCH v2 00/13] ceph: support idmapped mounts
To:     xiubli@redhat.com
Cc:     brauner@kernel.org, stgraber@ubuntu.com,
        linux-fsdevel@vger.kernel.org, Ilya Dryomov <idryomov@gmail.com>,
        Jeff Layton <jlayton@kernel.org>, ceph-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org
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version 3 was sent
https://lore.kernel.org/lkml/20230607152038.469739-1-aleksandr.mikhalitsyn@=
canonical.com/

On Wed, May 24, 2023 at 5:33=E2=80=AFPM Alexander Mikhalitsyn
<aleksandr.mikhalitsyn@canonical.com> wrote:
>
> Dear friends,
>
> This patchset was originally developed by Christian Brauner but I'll cont=
inue
> to push it forward. Christian allowed me to do that :)
>
> This feature is already actively used/tested with LXD/LXC project.
>
> v2 is just a rebased version of the original series with some small field=
 naming change.
>
> Git tree (based on https://github.com/ceph/ceph-client.git master):
> https://github.com/mihalicyn/linux/tree/fs.idmapped.ceph.v2
>
> Original description from Christian:
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> This patch series enables cephfs to support idmapped mounts, i.e. the
> ability to alter ownership information on a per-mount basis.
>
> Container managers such as LXD support sharaing data via cephfs between
> the host and unprivileged containers and between unprivileged containers.
> They may all use different idmappings. Idmapped mounts can be used to
> create mounts with the idmapping used for the container (or a different
> one specific to the use-case).
>
> There are in fact more use-cases such as remapping ownership for
> mountpoints on the host itself to grant or restrict access to different
> users or to make it possible to enforce that programs running as root
> will write with a non-zero {g,u}id to disk.
>
> The patch series is simple overall and few changes are needed to cephfs.
> There is one cephfs specific issue that I would like to discuss and
> solve which I explain in detail in:
>
> [PATCH 02/12] ceph: handle idmapped mounts in create_request_message()
>
> It has to do with how to handle mds serves which have id-based access
> restrictions configured. I would ask you to please take a look at the
> explanation in the aforementioned patch.
>
> The patch series passes the vfs and idmapped mount testsuite as part of
> xfstests. To run it you will need a config like:
>
> [ceph]
> export FSTYP=3Dceph
> export TEST_DIR=3D/mnt/test
> export TEST_DEV=3D10.103.182.10:6789:/
> export TEST_FS_MOUNT_OPTS=3D"-o name=3Dadmin,secret=3D$password
>
> and then simply call
>
> sudo ./check -g idmapped
>
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>
> Alexander Mikhalitsyn (1):
>   fs: export mnt_idmap_get/mnt_idmap_put
>
> Christian Brauner (12):
>   ceph: stash idmapping in mdsc request
>   ceph: handle idmapped mounts in create_request_message()
>   ceph: allow idmapped mknod inode op
>   ceph: allow idmapped symlink inode op
>   ceph: allow idmapped mkdir inode op
>   ceph: allow idmapped rename inode op
>   ceph: allow idmapped getattr inode op
>   ceph: allow idmapped permission inode op
>   ceph: allow idmapped setattr inode op
>   ceph/acl: allow idmapped set_acl inode op
>   ceph/file: allow idmapped atomic_open inode op
>   ceph: allow idmapped mounts
>
>  fs/ceph/acl.c                 |  2 +-
>  fs/ceph/dir.c                 |  4 ++++
>  fs/ceph/file.c                | 10 ++++++++--
>  fs/ceph/inode.c               | 15 +++++++++++----
>  fs/ceph/mds_client.c          | 29 +++++++++++++++++++++++++----
>  fs/ceph/mds_client.h          |  1 +
>  fs/ceph/super.c               |  2 +-
>  fs/mnt_idmapping.c            |  2 ++
>  include/linux/mnt_idmapping.h |  3 +++
>  9 files changed, 56 insertions(+), 12 deletions(-)
>
> --
> 2.34.1
>