diff options
| author | Fox Chen <foxhlchen@gmail.com> | 2021-05-27 17:16:12 +0800 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2021-06-18 11:36:08 -0600 |
| commit | 4a00e4bd59bbd5eac26f1792eb8d7d60f6cafe9a (patch) | |
| tree | 9c2ae459c14e0206d1e4baf178fc67b2ddadccb2 /Documentation/filesystems/path-lookup.rst | |
| parent | d2d3dd5ecce11ba560ff024e63ddb1640b7b27b0 (diff) | |
docs: path-lookup: i_op->follow_link replaced with i_op->get_link
follow_link has been replaced by get_link() which can be
called in RCU mode.
see commit: commit 6b2553918d8b ("replace ->follow_link() with
new method that could stay in RCU mode")
Signed-off-by: Fox Chen <foxhlchen@gmail.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20210527091618.287093-8-foxhlchen@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/filesystems/path-lookup.rst')
| -rw-r--r-- | Documentation/filesystems/path-lookup.rst | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst index 40b9afec4d60..4650c6427963 100644 --- a/Documentation/filesystems/path-lookup.rst +++ b/Documentation/filesystems/path-lookup.rst @@ -1060,13 +1060,11 @@ 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 out of +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 |