On Tue, Apr 26, 2022 at 12:19:49PM +0800, Yang Xu wrote:
> This has no functional change. Just create and export mode_strip_sgid
> api for the subsequent patch. This function is used to strip S_ISGID mode
> when init a new inode.
>
> Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> Reviewed-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
> Signed-off-by: Yang Xu <xuyang2018.jy@xxxxxxxxxxx>
> ---
Since this is a very sensitive patch series I think we need to be
annoyingly pedantic about the commit messages. This is really only
necessary because of the nature of these changes so you'll forgive me
for being really annoying about this. Here's what I'd change the commit
message to:
fs: add mode_strip_sgid() helper
Add a dedicated helper to handle the setgid bit when creating a new file
in a setgid directory. This is a preparatory patch for moving setgid
stripping into the vfs. The patch contains no functional changes.
Currently the setgid stripping logic is open-coded directly in
inode_init_owner() and the individual filesystems are responsible for
handling setgid inheritance. Since this has proven to be brittle as
evidenced by old issues we uncovered over the last months (see [1] to
[3] below) we will try to move this logic into the vfs.
Link: e014f37db1a2 ("xfs: use setattr_copy to set vfs inode attributes" [1]
Link: 01ea173e103e ("xfs: fix up non-directory creation in SGID directories") [2]
Link: fd84bfdddd16 ("ceph: fix up non-directory creation in SGID directories") [3]
