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From: Fox Chen <foxhlchen@gmail.com>
To: neilb@suse.de
Cc: Fox Chen <foxhlchen@gmail.com>,
	corbet@lwn.net, vegard.nossum@oracle.com,
	viro@zeniv.linux.org.uk, rdunlap@infradead.org,
	grandmaster@al2klimov.de, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org
Subject: [PATCH v2 04/12] docs: path-lookup: update do_last() part
Date: Tue, 16 Mar 2021 13:47:19 +0800
Message-ID: <20210316054727.25655-5-foxhlchen@gmail.com> (raw)
In-Reply-To: <20210316054727.25655-1-foxhlchen@gmail.com>

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: commit c5971b8c6354 ("take post-lookup
part of do_last() out of loop")

Signed-off-by: Fox Chen <foxhlchen@gmail.com>
---
 Documentation/filesystems/path-lookup.rst | 35 ++++++++++++-----------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst
index b6a301b78121..a65cb477d524 100644
--- a/Documentation/filesystems/path-lookup.rst
+++ b/Documentation/filesystems/path-lookup.rst
@@ -495,11 +495,11 @@ 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
-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
@@ -1199,26 +1199,27 @@ 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()`` 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.
 
 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()`` is the most interesting as it works in tandem
+with ``do_open()`` 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()`` and ``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()`` is used after
+   ``open_last_lookup()`` 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
-- 
2.30.2


  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-16  5:47 [PATCH v2 00/12] docs: path-lookup: Update pathlookup docs Fox Chen
2021-03-16  5:47 ` [PATCH v2 01/12] docs: path-lookup: update follow_managed() part Fox Chen
2021-04-19  0:52   ` NeilBrown
2021-04-19  2:17   ` Matthew Wilcox
2021-04-19  2:33     ` Fox Chen
2021-04-19  3:25       ` Matthew Wilcox
2021-04-19  3:33         ` Fox Chen
2021-04-19 19:22           ` Jonathan Corbet
2021-04-20  1:12             ` Fox Chen
2021-03-16  5:47 ` [PATCH v2 02/12] docs: path-lookup: update path_to_nameidata() part Fox Chen
2021-04-19  1:00   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 03/12] docs: path-lookup: update path_mountpoint() part Fox Chen
2021-04-19  1:03   ` NeilBrown
2021-03-16  5:47 ` Fox Chen [this message]
2021-04-19  1:17   ` [PATCH v2 04/12] docs: path-lookup: update do_last() part NeilBrown
2021-03-16  5:47 ` [PATCH v2 05/12] docs: path-lookup: remove filename_mountpoint Fox Chen
2021-04-19  1:20   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 06/12] docs: path-lookup: Add macro name to symlink limit description Fox Chen
2021-04-19  1:22   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 07/12] docs: path-lookup: i_op->follow_link replaced with i_op->get_link Fox Chen
2021-04-19  1:28   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 08/12] docs: path-lookup: update i_op->put_link and cookie description Fox Chen
2021-04-19  1:37   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 09/12] docs: path-lookup: no get_link() Fox Chen
2021-04-19  1:41   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 10/12] docs: path-lookup: update WALK_GET, WALK_PUT desc Fox Chen
2021-04-19  1:47   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 11/12] docs: path-lookup: update get_link() ->follow_link description Fox Chen
2021-04-19  1:54   ` NeilBrown
2021-03-16  5:47 ` [PATCH v2 12/12] docs: path-lookup: update symlink description Fox Chen
2021-04-19  1:59   ` NeilBrown
2021-04-19  2:34     ` Fox Chen
2021-04-13 21:18 ` [PATCH v2 00/12] docs: path-lookup: Update pathlookup docs Jonathan Corbet
2021-04-13 22:26   ` NeilBrown

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