Re: [GIT PULL] overlayfs update for 4.9

[Al Viro]

On Wed, Oct 05, 2016 at 09:52:10PM +0200, Miklos Szeredi wrote:
> Hi Al,
> 
> Please pull from:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-viro
> 
> This has an assortment of fixes and cleanups for overlayfs.
> 
> It also touches the VFS:
> 
>  - add the vfs_get_link() helper for calling i_op->get_link();
>  - fix mnt_want_write_file() to freeze protect the underlying sb instead of
>    overlay sb;
>  - allow vfs_clone_file_range() to be called by overlayfs.

Could you explain why e.g. fsetxattr() needs a different treatment in
"vfs: mnt_want_write_file() should freeze protect underlying sb"?