[v2,03/30] fs: rename current get acl method

The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

The current inode operation for getting posix acls takes an inode
argument but various filesystems (e.g., 9p, cifs, overlayfs) need access
to the dentry. In contrast to the ->set_acl() inode operation we cannot
simply extend ->get_acl() to take a dentry argument. The ->get_acl()
inode operation is called from:

acl_permission_check()
-> check_acl()
   -> get_acl()

which is part of generic_permission() which in turn is part of
inode_permission(). Both generic_permission() and inode_permission() are
called in the ->permission() handler of various filesystems (e.g.,
overlayfs). So simply passing a dentry argument to ->get_acl() would
amount to also having to pass a dentry argument to ->permission(). We
should avoid this unnecessary change.

So instead of extending the existing inode operation rename it from
->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that
passes a dentry argument and which filesystems that need access to the
dentry can implement instead of ->get_inode_acl(). Filesystems like cifs
which allow setting and getting posix acls but not using them for
permission checking during lookup can simply not implement
->get_inode_acl().

This is intended to be a non-functional change.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Suggested-by/Inspired-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---

Notes:
    /* v2 */
    unchanged

 Documentation/filesystems/locking.rst |  4 ++--
 Documentation/filesystems/porting.rst |  4 ++--
 Documentation/filesystems/vfs.rst     |  2 +-
 fs/9p/vfs_inode_dotl.c                |  4 ++--
 fs/bad_inode.c                        |  2 +-
 fs/btrfs/inode.c                      |  6 +++---
 fs/ceph/dir.c                         |  2 +-
 fs/ceph/inode.c                       |  2 +-
 fs/erofs/inode.c                      |  6 +++---
 fs/erofs/namei.c                      |  2 +-
 fs/ext2/file.c                        |  2 +-
 fs/ext2/namei.c                       |  4 ++--
 fs/ext4/file.c                        |  2 +-
 fs/ext4/namei.c                       |  4 ++--
 fs/f2fs/file.c                        |  2 +-
 fs/f2fs/namei.c                       |  4 ++--
 fs/fuse/dir.c                         |  4 ++--
 fs/gfs2/inode.c                       |  4 ++--
 fs/jffs2/dir.c                        |  2 +-
 fs/jffs2/file.c                       |  2 +-
 fs/jfs/file.c                         |  2 +-
 fs/jfs/namei.c                        |  2 +-
 fs/namei.c                            |  2 +-
 fs/nfs/nfs3proc.c                     |  4 ++--
 fs/ntfs3/file.c                       |  2 +-
 fs/ntfs3/namei.c                      |  4 ++--
 fs/ocfs2/file.c                       |  4 ++--
 fs/ocfs2/namei.c                      |  2 +-
 fs/orangefs/inode.c                   |  2 +-
 fs/orangefs/namei.c                   |  2 +-
 fs/overlayfs/dir.c                    |  2 +-
 fs/overlayfs/inode.c                  |  4 ++--
 fs/posix_acl.c                        | 27 ++++++++++++++-------------
 fs/reiserfs/file.c                    |  2 +-
 fs/reiserfs/namei.c                   |  4 ++--
 fs/xfs/xfs_iops.c                     |  6 +++---
 include/linux/fs.h                    |  6 +++---
 37 files changed, 71 insertions(+), 70 deletions(-)

Message ID	20220926140827.142806-4-brauner@kernel.org (mailing list archive)
State	Superseded
Delegated to:	Paul Moore
Headers	show Return-Path: <linux-security-module-owner@kernel.org> From: Christian Brauner <brauner@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Christian Brauner <brauner@kernel.org>, Seth Forshee <sforshee@kernel.org>, Christoph Hellwig <hch@lst.de>, Al Viro <viro@zeniv.linux.org.uk>, linux-security-module@vger.kernel.org Subject: [PATCH v2 03/30] fs: rename current get acl method Date: Mon, 26 Sep 2022 16:08:00 +0200 Message-Id: <20220926140827.142806-4-brauner@kernel.org> In-Reply-To: <20220926140827.142806-1-brauner@kernel.org> References: <20220926140827.142806-1-brauner@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	acl: add vfs posix acl api \| expand [v2,00/30] acl: add vfs posix acl api [v2,01/30] orangefs: rework posix acl handling when creating new filesystem objects [v2,02/30] fs: pass dentry to set acl method [v2,03/30] fs: rename current get acl method [v2,04/30] fs: add new get acl method [v2,05/30] cifs: implement get acl method [v2,06/30] cifs: implement set acl method [v2,07/30] 9p: implement get acl method [v2,08/30] 9p: implement set acl method [v2,09/30] acl: add vfs_set_acl() [v2,10/30] security: add set acl hook [v2,11/30] selinux: implement set acl hook [v2,12/30] smack: implement set acl hook [v2,13/30] evm: implement set acl hook [v2,14/30] acl: use set acl hook [v2,15/30] evm: add post set acl hook [v2,16/30] acl: add vfs_get_acl() [v2,17/30] acl: add vfs_remove_acl() [v2,18/30] evm: simplify evm_xattr_acl_change() [v2,19/30] ksmbd: use vfs_remove_acl() [v2,20/30] ecryptfs: implement get acl method [v2,21/30] ecryptfs: implement set acl method [v2,22/30] ovl: implement get acl method [v2,23/30] ovl: implement set acl method [v2,24/30] ovl: use posix acl api [v2,25/30] xattr: use posix acl api [v2,26/30] ecryptfs: use stub posix acl handlers [v2,27/30] ovl: use stub posix acl handlers [v2,28/30] cifs: use stub posix acl handlers [v2,29/30] 9p: use stub posix acl handlers [v2,30/30] acl: remove a slew of now unused helpers

[v2,03/30] fs: rename current get acl method

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