Message-ID: <f3864ed6-8c97-8a7a-f268-dab29eb2fb21@redhat.com>
Date:   Fri, 9 Jun 2023 09:57:13 +0800
From:   Xiubo Li <xiubli@...hat.com>
To:     Alexander Mikhalitsyn <aleksandr.mikhalitsyn@...onical.com>
Cc:     brauner@...nel.org, stgraber@...ntu.com,
        linux-fsdevel@...r.kernel.org, Ilya Dryomov <idryomov@...il.com>,
        Jeff Layton <jlayton@...nel.org>, ceph-devel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 00/14] ceph: support idmapped mounts


On 6/8/23 23:42, Alexander Mikhalitsyn wrote:
> Dear friends,
>
> This patchset was originally developed by Christian Brauner but I'll continue
> to push it forward. Christian allowed me to do that :)
>
> This feature is already actively used/tested with LXD/LXC project.
>
> Git tree (based on https://github.com/ceph/ceph-client.git master):

Could you rebase these patches to 'testing' branch ?

And you still have missed several places, for example the following cases:


    1    269  fs/ceph/addr.c <<ceph_netfs_issue_op_inline>>
              req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, 
mode);
    2    389  fs/ceph/dir.c <<ceph_readdir>>
              req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
    3    789  fs/ceph/dir.c <<ceph_lookup>>
              req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
    ...


For this requests you also need to set the real idmap.


Thanks

- Xiubo



> v5: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v5
> current: https://github.com/mihalicyn/linux/tree/fs.idmapped.ceph
>
> In the version 3 I've changed only two commits:
> - fs: export mnt_idmap_get/mnt_idmap_put
> - ceph: allow idmapped setattr inode op
> and added a new one:
> - ceph: pass idmap to __ceph_setattr
>
> In the version 4 I've reworked the ("ceph: stash idmapping in mdsc request")
> commit. Now we take idmap refcounter just in place where req->r_mnt_idmap
> is filled. It's more safer approach and prevents possible refcounter underflow
> on error paths where __register_request wasn't called but ceph_mdsc_release_request is
> called.
>
> Changelog for version 5:
> - a few commits were squashed into one (as suggested by Xiubo Li)
> - started passing an idmapping everywhere (if possible), so a caller
> UID/GID-s will be mapped almost everywhere (as suggested by Xiubo Li)
>
> I can confirm that this version passes xfstests.
>
> Links to previous versions:
> v1: https://lore.kernel.org/all/20220104140414.155198-1-brauner@kernel.org/
> v2: https://lore.kernel.org/lkml/20230524153316.476973-1-aleksandr.mikhalitsyn@canonical.com/
> tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v2
> v3: https://lore.kernel.org/lkml/20230607152038.469739-1-aleksandr.mikhalitsyn@canonical.com/#t
> v4: https://lore.kernel.org/lkml/20230607180958.645115-1-aleksandr.mikhalitsyn@canonical.com/#t
> tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v4
>
> Kind regards,
> Alex
>
> Original description from Christian:
> ========================================================================
> 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=ceph
> export TEST_DIR=/mnt/test
> export TEST_DEV=10.103.182.10:6789:/
> export TEST_FS_MOUNT_OPTS="-o name=admin,secret=$password
>
> and then simply call
>
> sudo ./check -g idmapped
>
> ========================================================================
>
> Alexander Mikhalitsyn (5):
>    fs: export mnt_idmap_get/mnt_idmap_put
>    ceph: pass idmap to __ceph_setattr
>    ceph: pass idmap to ceph_do_getattr
>    ceph: pass idmap to __ceph_setxattr
>    ceph: pass idmap to ceph_open/ioctl_set_layout
>
> Christian Brauner (9):
>    ceph: stash idmapping in mdsc request
>    ceph: handle idmapped mounts in create_request_message()
>    ceph: pass an idmapping to mknod/symlink/mkdir/rename
>    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                 |  8 ++++----
>   fs/ceph/addr.c                |  3 ++-
>   fs/ceph/caps.c                |  3 ++-
>   fs/ceph/dir.c                 |  4 ++++
>   fs/ceph/export.c              |  2 +-
>   fs/ceph/file.c                | 21 ++++++++++++++-----
>   fs/ceph/inode.c               | 38 +++++++++++++++++++++--------------
>   fs/ceph/ioctl.c               |  9 +++++++--
>   fs/ceph/mds_client.c          | 27 +++++++++++++++++++++----
>   fs/ceph/mds_client.h          |  1 +
>   fs/ceph/quota.c               |  2 +-
>   fs/ceph/super.c               |  6 +++---
>   fs/ceph/super.h               | 14 ++++++++-----
>   fs/ceph/xattr.c               | 18 +++++++++--------
>   fs/mnt_idmapping.c            |  2 ++
>   include/linux/mnt_idmapping.h |  3 +++
>   16 files changed, 111 insertions(+), 50 deletions(-)
>

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