Re: [PATCH v2 09/10] fs: add i_user_ns() helper

Seth Forshee
2021-12-02T17:40:54Z

On Tue, Nov 30, 2021 at 01:10:31PM +0100, Christian Brauner wrote:
> From: Christian Brauner <christian.brauner@ubuntu.com>
>
> Since we'll be passing the filesystem's idmapping in even more places in
> the following patches and we do already dereference struct inode to get
> to the filesystem's idmapping multiple times add a tiny helper.
>
> Link: https://lore.kernel.org/r/20211123114227.3124056-10-brauner@kernel.org (v1)
> Cc: Seth Forshee <sforshee@digitalocean.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> CC: linux-fsdevel@vger.kernel.org
> Reviewed-by: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> ---

Reviewed-by: Seth Forshee <sforshee@digitalocean.com>

> /* v2 */
> unchanged
> ---
> include/linux/fs.h | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 7c0499b63a02..c7f72b78ab7e 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1600,6 +1600,11 @@ struct super_block {
> struct list_head s_inodes_wb; /* writeback inodes */
> } __randomize_layout;
>
> +static inline struct user_namespace *i_user_ns(const struct inode *inode)
> +{
> + return inode->i_sb->s_user_ns;
> +}
> +
> /* Helper functions so that in most cases filesystems will
> * not need to deal directly with kuid_t and kgid_t and can
> * instead deal with the raw numeric values that are stored
> @@ -1607,22 +1612,22 @@ struct super_block {
> */
> static inline uid_t i_uid_read(const struct inode *inode)
> {
> - return from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
> + return from_kuid(i_user_ns(inode), inode->i_uid);
> }
>
> static inline gid_t i_gid_read(const struct inode *inode)
> {
> - return from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
> + return from_kgid(i_user_ns(inode), inode->i_gid);
> }
>
> static inline void i_uid_write(struct inode *inode, uid_t uid)
> {
> - inode->i_uid = make_kuid(inode->i_sb->s_user_ns, uid);
> + inode->i_uid = make_kuid(i_user_ns(inode), uid);
> }
>
> static inline void i_gid_write(struct inode *inode, gid_t gid)
> {
> - inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid);
> + inode->i_gid = make_kgid(i_user_ns(inode), gid);
> }
>
> /**
> --
> 2.30.2
>