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 testing):
v9: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v9
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)
Changelog for version 6:
- rebased on top of testing branch
- passed an idmapping in a few places (readdir, ceph_netfs_issue_op_inline)
Changelog for version 7:
- rebased on top of testing branch
- this thing now requires a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
https://github.com/ceph/ceph/pull/52575
Changelog for version 8:
- rebased on top of testing branch
- added enable_unsafe_idmap module parameter to make idmapped mounts
work with old MDS server versions
- properly handled case when old MDS used with new kernel client
Changelog for version 9:
- added "struct_len" field in struct ceph_mds_request_head as requested by Xiubo Li
I can confirm that this version passes xfstests and
tested with old MDS (without CEPHFS_FEATURE_HAS_OWNER_UIDGID)
and with recent MDS version.
Links to previous versions:
v1: https://lore.kernel.org/all/[email protected]/
v2: https://lore.kernel.org/lkml/[email protected]/
tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v2
v3: https://lore.kernel.org/lkml/[email protected]/#t
v4: https://lore.kernel.org/lkml/[email protected]/#t
tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v4
v5: https://lore.kernel.org/lkml/[email protected]/#t
tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v5
v6: https://lore.kernel.org/lkml/[email protected]/
tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v6
v7: https://lore.kernel.org/all/[email protected]/
tree: https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph.v7
v8: https://lore.kernel.org/all/[email protected]/
tree: -
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 (3):
fs: export mnt_idmap_get/mnt_idmap_put
ceph: add enable_unsafe_idmap module parameter
ceph: pass idmap to __ceph_setattr
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
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 | 6 +--
fs/ceph/crypto.c | 2 +-
fs/ceph/dir.c | 3 ++
fs/ceph/file.c | 10 ++++-
fs/ceph/inode.c | 29 +++++++++------
fs/ceph/mds_client.c | 70 ++++++++++++++++++++++++++++++++---
fs/ceph/mds_client.h | 8 +++-
fs/ceph/super.c | 7 +++-
fs/ceph/super.h | 3 +-
fs/mnt_idmapping.c | 2 +
include/linux/ceph/ceph_fs.h | 5 ++-
include/linux/mnt_idmapping.h | 3 ++
12 files changed, 121 insertions(+), 27 deletions(-)
--
2.34.1
From: Christian Brauner <[email protected]>
When sending a mds request cephfs will send relevant data for the
requested operation. For creation requests the caller's fs{g,u}id is
used to set the ownership of the newly created filesystem object. For
setattr requests the caller can pass in arbitrary {g,u}id values to
which the relevant filesystem object is supposed to be changed.
If the caller is performing the relevant operation via an idmapped mount
cephfs simply needs to take the idmapping into account when it sends the
relevant mds request.
In order to support idmapped mounts for cephfs we stash the idmapping
whenever they are relevant for the operation for the duration of the
request. Since mds requests can be queued and performed asynchronously
we make sure to keep the idmapping around and release it once the
request has finished.
In follow-up patches we will use this to send correct ownership
information over the wire. This patch just adds the basic infrastructure
to keep the idmapping around. The actual conversion patches are all
fairly minimal.
Cc: Xiubo Li <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Ilya Dryomov <[email protected]>
Cc: [email protected]
Signed-off-by: Christian Brauner <[email protected]>
Signed-off-by: Alexander Mikhalitsyn <[email protected]>
---
v4:
- don't call mnt_idmap_get(..) in __register_request
---
fs/ceph/mds_client.c | 5 +++++
fs/ceph/mds_client.h | 1 +
2 files changed, 6 insertions(+)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 9aae39289b43..8829f55103da 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -12,6 +12,7 @@
#include <linux/bits.h>
#include <linux/ktime.h>
#include <linux/bitmap.h>
+#include <linux/mnt_idmapping.h>
#include "super.h"
#include "crypto.h"
@@ -1121,6 +1122,8 @@ void ceph_mdsc_release_request(struct kref *kref)
kfree(req->r_path1);
kfree(req->r_path2);
put_cred(req->r_cred);
+ if (req->r_mnt_idmap)
+ mnt_idmap_put(req->r_mnt_idmap);
if (req->r_pagelist)
ceph_pagelist_release(req->r_pagelist);
kfree(req->r_fscrypt_auth);
@@ -1180,6 +1183,8 @@ static void __register_request(struct ceph_mds_client *mdsc,
insert_request(&mdsc->request_tree, req);
req->r_cred = get_current_cred();
+ if (!req->r_mnt_idmap)
+ req->r_mnt_idmap = &nop_mnt_idmap;
if (mdsc->oldest_tid == 0 && req->r_op != CEPH_MDS_OP_SETFILELOCK)
mdsc->oldest_tid = req->r_tid;
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 717a7399bacb..e3bbf3ba8ee8 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -300,6 +300,7 @@ struct ceph_mds_request {
int r_fmode; /* file mode, if expecting cap */
int r_request_release_offset;
const struct cred *r_cred;
+ struct mnt_idmap *r_mnt_idmap;
struct timespec64 r_stamp;
/* for choosing which mds to send this request to */
--
2.34.1