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

[Seth Forshee <sforshee@digitalocean.com>]

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
>