fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap

Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/ksmbd/oplock.c b/fs/ksmbd/oplock.c
index d7d47b82451d..2e54ded4d92c 100644
--- a/fs/ksmbd/oplock.c
+++ b/fs/ksmbd/oplock.c
@@ -1608,9 +1608,9 @@ void create_posix_rsp_buf(char *cc, struct ksmbd_file *fp)
 {
 	struct create_posix_rsp *buf;
 	struct inode *inode = file_inode(fp->filp);
-	struct user_namespace *user_ns = file_mnt_user_ns(fp->filp);
-	vfsuid_t vfsuid = i_uid_into_vfsuid(user_ns, inode);
-	vfsgid_t vfsgid = i_gid_into_vfsgid(user_ns, inode);
+	struct mnt_idmap *idmap = file_mnt_idmap(fp->filp);
+	vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
+	vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
 
 	buf = (struct create_posix_rsp *)cc;
 	memset(buf, 0, sizeof(struct create_posix_rsp));