follow_link has been replaced by get_link() which can be called in RCU mode. see commit: 6b2553918d8b4e6de9853fd6315bec7271a2e592 Signed-off-by: Fox Chen <foxhlchen@xxxxxxxxx> --- Documentation/filesystems/path-lookup.rst | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst index 25d2a5a59f45..0a362849b26f 100644 --- a/Documentation/filesystems/path-lookup.rst +++ b/Documentation/filesystems/path-lookup.rst @@ -1062,13 +1062,11 @@ filesystem cannot successfully get a reference in RCU-walk mode, it must return ``-ECHILD`` and ``unlazy_walk()`` will be called to return to REF-walk mode in which the filesystem is allowed to sleep. -The place for all this to happen is the ``i_op->follow_link()`` inode -method. In the present mainline code this is never actually called in -RCU-walk mode as the rewrite is not quite complete. It is likely that -in a future release this method will be passed an ``inode`` pointer when -called in RCU-walk mode so it both (1) knows to be careful, and (2) has the -validated pointer. Much like the ``i_op->permission()`` method we -looked at previously, ``->follow_link()`` would need to be careful that +The place for all this to happen is the ``i_op->get_link()`` inode +method. This is called both in RCU-walk and REF-walk. In RCU-walk the +``dentry*`` argument is NULL, ``->get_link()`` can return -ECHILD to drop +RCU-walk. Much like the ``i_op->permission()`` method we +looked at previously, ``->get_link()`` would need to be careful that all the data structures it references are safe to be accessed while holding no counted reference, only the RCU lock. Though getting a reference with ``->follow_link()`` is not yet done in RCU-walk mode, the -- 2.30.0
