On Mon, Apr 19, 2021 at 9:59 AM NeilBrown <neilb@xxxxxxx> wrote: > > On Tue, Mar 16 2021, Fox Chen wrote: > > > instead of lookup_real()/vfs_create(), i_op->lookup() and > > i_op->create() will be called directly. > > > > update vfs_open() logic > > > > should_follow_link is merged into lookup_last() or open_last_lookup() > > which returns symlink name instead of an integer. > > > > Signed-off-by: Fox Chen <foxhlchen@xxxxxxxxx> > > --- > > Documentation/filesystems/path-lookup.rst | 13 ++++++------- > > 1 file changed, 6 insertions(+), 7 deletions(-) > > > > diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst > > index eef6e9f68fba..adbc714740c2 100644 > > --- a/Documentation/filesystems/path-lookup.rst > > +++ b/Documentation/filesystems/path-lookup.rst > > @@ -1202,16 +1202,15 @@ the code. > > 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 > > - will perform the separate ``lookup_real()`` and ``vfs_create()`` steps > > + will perform the separate ``i_op->lookup()`` and ``i_op->create()`` steps > > directly. In the later case the actual "open" of this newly found or > > created file will be performed by ``vfs_open()``, just as if the name > > were found in the dcache. > > > > 2. ``vfs_open()`` can fail with ``-EOPENSTALE`` if the cached information > > - wasn't quite current enough. Rather than restarting the lookup from > > - the top with ``LOOKUP_REVAL`` set, ``lookup_open()`` is called instead, > > - giving the filesystem a chance to resolve small inconsistencies. > > - If that doesn't work, only then is the lookup restarted from the top. > > + wasn't quite current enough. If it's in RCU-walk -ECHILD will be returned > > + otherwise will return -ESTALE. When -ESTALE is returned, the caller may > > "otherwise -ESTALE is returned". > If you don't like repeating "is returned", then maybe: > "... -ECHILD will be returned, otherwise the result is -ESTALE". > > > > + retry with LOOKUP_REVAL flag set. > > > > 3. An open with O_CREAT **does** follow a symlink in the final component, > > unlike other creation system calls (like ``mkdir``). So the sequence:: > > @@ -1221,8 +1220,8 @@ the code. > > > > will create a file called ``/tmp/bar``. This is not permitted if > > ``O_EXCL`` is set but otherwise is handled for an O_CREAT open much > > - like for a non-creating open: ``should_follow_link()`` returns ``1``, and > > - so does ``do_last()`` so that ``trailing_symlink()`` gets called and the > > + like for a non-creating open: ``lookup_last()`` or ``open_last_lookup()`` > > + returns a non ``Null`` value, and ``link_path_walk()`` gets called and the > > "NULL", not "Null". > > This those changes, > Reviewed-by: NeilBrown <neilb@xxxxxxx> > > Thanks for a lot of all these improvements!! and apologies for the delay > in the review. Thanks for the review, I will fix them and send the next version back. > Thanks, > NeilBrown > > > > open process continues on the symlink that was found. > > > > Updating the access time > > -- > > 2.30.2 thanks, fox
