Re: [PATCH v2 03/12] docs: path-lookup: update path_mountpoint() part

NeilBrown
2021-04-19T01:04:08Z

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On Tue, Mar 16 2021, Fox Chen wrote:

> path_mountpoint() doesn't exist anymore. Have been folded
> into path_lookup_at when flag is set with LOOKUP_MOUNTPOINT.
> Check commit: commit 161aff1d93abf0e ("LOOKUP_MOUNTPOINT: fold
> path_mountpointat() into path_lookupat()")
>
> Signed-off-by: Fox Chen <foxhlchen@gmail.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 a29d714431a3..b6a301b78121 100644
> --- a/Documentation/filesystems/path-lookup.rst
> +++ b/Documentation/filesystems/path-lookup.rst
> @@ -472,7 +472,7 @@ Handling the final component
> ``nd->last_type`` to refer to the final component of the path. It does
> not call ``walk_component()`` that last time. Handling that final
> component remains for the caller to sort out. Those callers are
> -``path_lookupat()``, ``path_parentat()``, ``path_mountpoint()`` and
> +``path_lookupat()``, ``path_parentat()`` and
> ``path_openat()`` each of which handles the differing requirements of
> different system calls.
>
> @@ -488,12 +488,10 @@ perform their operation.
> object is wanted such as by ``stat()`` or ``chmod()``. It essentially just
> calls ``walk_component()`` on the final component through a call to
> ``lookup_last()``. ``path_lookupat()`` returns just the final dentry.
> -
> -``path_mountpoint()`` handles the special case of unmounting which must
> -not try to revalidate the mounted filesystem. It effectively
> -contains, through a call to ``mountpoint_last()``, an alternate
> -implementation of ``lookup_slow()`` which skips that step. This is
> -important when unmounting a filesystem that is inaccessible, such as
> +It is worth noting that when flag ``LOOKUP_MOUNTPOINT`` is set,
> +``path_lookupat()`` will unset LOOKUP_JUMPED in nameidata so that in the further

I would say "subsequent" rather than "further".

Either way:
Reviewed-by: NeilBrown <neilb@suse.de>

Thanks,
NeilBrown

> +path traversal ``d_weak_revalidate()`` won't be called.
> +This is important when unmounting a filesystem that is inaccessible, such as
> one provided by a dead NFS server.
>
> Finally ``path_openat()`` is used for the ``open()`` system call; it
> --
> 2.30.2

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