Documentation/filesystems/vfs.txt: document how ->i_link works

	argument.  If request can't be handled without leaving RCU mode,

	argument.  If request can't be handled without leaving RCU mode,

	have it return ERR_PTR(-ECHILD).

	have it return ERR_PTR(-ECHILD).

	If the filesystem stores the symlink target in ->i_link, the

	VFS may use it directly without calling ->get_link(); however,

	->get_link() must still be provided.  ->i_link must not be

	freed until after an RCU grace period.  Writing to ->i_link

	post-iget() time requires a 'release' memory barrier.

  readlink: this is now just an override for use by readlink(2) for the

  readlink: this is now just an override for use by readlink(2) for the

	cases when ->get_link uses nd_jump_link() or object is not in

	cases when ->get_link uses nd_jump_link() or object is not in

	fact a symlink.  Normally filesystems should only implement

	fact a symlink.  Normally filesystems should only implement