On Tue, Jan 26 2021, Fox Chen wrote: > traling_symlink() was merged into lookup_last, do_last(). > > do_last() has later been split into open_last_lookups() > and do_open(). > > see related commit: c5971b8c6354a95c9ee7eb722928af5000bac247 > > Signed-off-by: Fox Chen <foxhlc...@gmail.com> > --- > Documentation/filesystems/path-lookup.rst | 34 +++++++++++------------ > 1 file changed, 17 insertions(+), 17 deletions(-) > > diff --git a/Documentation/filesystems/path-lookup.rst > b/Documentation/filesystems/path-lookup.rst > index 4e77c8520fa9..1f05b1417a55 100644 > --- a/Documentation/filesystems/path-lookup.rst > +++ b/Documentation/filesystems/path-lookup.rst > @@ -496,11 +496,11 @@ one provided by a dead NFS server. In the current > kernel, path_mountpoint > has been merged into ``path_lookup_at()`` with a new flag LOOKUP_MOUNTPOINT. > > Finally ``path_openat()`` is used for the ``open()`` system call; it > -contains, in support functions starting with "``do_last()``", all the > +contains, in support functions starting with "``open_last_lookups()``", all > the > complexity needed to handle the different subtleties of O_CREAT (with > or without O_EXCL), final "``/``" characters, and trailing symbolic > links. We will revisit this in the final part of this series, which > -focuses on those symbolic links. "``do_last()``" will sometimes, but > +focuses on those symbolic links. "``open_last_lookups()``" will sometimes, > but > not always, take ``i_rwsem``, depending on what it finds. > > Each of these, or the functions which call them, need to be alert to > @@ -1201,26 +1201,26 @@ symlink. > This case is handled by the relevant caller of ``link_path_walk()``, such as > ``path_lookupat()`` using a loop that calls ``link_path_walk()``, and then > handles the final component. If the final component is a symlink > -that needs to be followed, then ``trailing_symlink()`` is called to set > -things up properly and the loop repeats, calling ``link_path_walk()`` > -again. This could loop as many as 40 times if the last component of > -each symlink is another symlink. > +that needs to be followed, then ``open_last_lookups()`` and ``do_open()`` is > +called to set things up properly and the loop repeats, calling
This implies that do_open() is inside the loop (in path_openat()). But it isn't, it comes after the loop. (I haven't closely examined this rest of this patch). NeilBrown > +``link_path_walk()`` again. This could loop as many as 40 times if the last > +component of each symlink is another symlink. > > The various functions that examine the final component and possibly > -report that it is a symlink are ``lookup_last()``, ``mountpoint_last()`` > -and ``do_last()``, each of which use the same convention as > -``walk_component()`` of returning ``1`` if a symlink was found that needs > -to be followed. > +report that it is a symlink are ``lookup_last()``, ``open_last_lookups()`` > +, each of which use the same convention as > +``walk_component()`` of returning ``char *name`` if a symlink was found that > +needs to be followed. > > -Of these, ``do_last()`` is the most interesting as it is used for > -opening a file. Part of ``do_last()`` runs with ``i_rwsem`` held and this > -part is in a separate function: ``lookup_open()``. > +Of these, ``open_last_lookups()``, ``do_open()`` is the most interesting as > it is > +used for opening a file. Part of ``open_last_lookups()`` runs with > ``i_rwsem`` > +held and this part is in a separate function: ``lookup_open()``. > > -Explaining ``do_last()`` completely is beyond the scope of this article, > -but a few highlights should help those interested in exploring the > -code. > +Explaining ``open_last_lookups()``, ``do_open()`` completely is beyond the > scope > +of this article, but a few highlights should help those interested in > exploring > +the code. > > -1. Rather than just finding the target file, ``do_last()`` needs to open > +1. Rather than just finding the target file, ``do_open()`` needs to open > it. If the file was found in the dcache, then ``vfs_open()`` is used for > this. If not, then ``lookup_open()`` will either call ``atomic_open()`` > (if > the filesystem provides it) to combine the final lookup with the open, or > -- > 2.30.0
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