linux-kernel - Re: [PATCH v2 10/12] docs: path-lookup: update WALK_GET, WALK

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Message-ID: <87sg3n11vt.fsf@notabene.neil.brown.name>
Date:   Mon, 19 Apr 2021 11:47:34 +1000
From:   NeilBrown <neilb@...e.de>
To:     Fox Chen <foxhlchen@...il.com>
Cc:     Fox Chen <foxhlchen@...il.com>, corbet@....net,
        vegard.nossum@...cle.com, viro@...iv.linux.org.uk,
        rdunlap@...radead.org, grandmaster@...klimov.de,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        gregkh@...uxfoundation.org
Subject: Re: [PATCH v2 10/12] docs: path-lookup: update WALK_GET, WALK_PUT desc

On Tue, Mar 16 2021, Fox Chen wrote:

> WALK_GET is changed to WALK_TRAILING with a different meaning.
> Here it should be WALK_NOFOLLOW. WALK_PUT dosn't exist, we have
> WALK_MORE.
>
> WALK_PUT == !WALK_MORE
>
> And there is not should_follow_link().
>
> Related commits:
> commit 8c4efe22e7c4 ("namei: invert the meaning of WALK_FOLLOW")
> commit 1c4ff1a87e46 ("namei: invert WALK_PUT logics")
>
> Signed-off-by: Fox Chen <foxhlchen@...il.com>
> ---
>  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 0d41c61f7e4f..abd0153e2415 100644
> --- a/Documentation/filesystems/path-lookup.rst
> +++ b/Documentation/filesystems/path-lookup.rst
> @@ -1123,13 +1123,11 @@ stack in ``walk_component()`` immediately when the symlink is found;
>  old symlink as it walks that last component.  So it is quite
>  convenient for ``walk_component()`` to release the old symlink and pop
>  the references just before pushing the reference information for the
> -new symlink.  It is guided in this by two flags; ``WALK_GET``, which
> -gives it permission to follow a symlink if it finds one, and
> -``WALK_PUT``, which tells it to release the current symlink after it has been
> -followed.  ``WALK_PUT`` is tested first, leading to a call to
> -``put_link()``.  ``WALK_GET`` is tested subsequently (by
> -``should_follow_link()``) leading to a call to ``pick_link()`` which sets
> -up the stack frame.
> +new symlink.  It is guided in this by two flags; ``WALK_NOFOLLOW``, which

There are 3 flags now.  You haven't documented WALK_TRAIlING.


> +suggests whether to follow a symlink if it finds one, and

I don't think it is a suggestion.

.. which forbits it from following a symlink if it finds one, and
WALK_MORE which indicates that it is yet too early to release the
current symlink.

> +``WALK_MORE``, which tells whether to release the current symlink after it has
> +been followed.  ``WALK_MORE`` is tested first, leading to a call to
> +``put_link()``.

I don't think that "tested first" sentence is relevant any more.

Thanks,
NeilBrown

>  
>  Symlinks with no final component
>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> -- 
> 2.30.2

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