Re: [PATCH v2 06/14] fs: convert debugfs to use simple_remove() helper

[Amir Goldstein <amir73il@gmail.com>]

On Thu, May 16, 2019 at 1:35 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, May 16, 2019 at 01:26:33PM +0300, Amir Goldstein wrote:
> > This will allow generating fsnotify delete events after the
> > fsnotify_nameremove() hook is removed from d_delete().
> >
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
> >  fs/debugfs/inode.c | 20 ++++----------------
> >  1 file changed, 4 insertions(+), 16 deletions(-)
> >
> > diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
> > index acef14ad53db..bc96198df1d4 100644
> > --- a/fs/debugfs/inode.c
> > +++ b/fs/debugfs/inode.c
> > @@ -617,13 +617,10 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
> >  }
> >  EXPORT_SYMBOL_GPL(debugfs_create_symlink);
> >
> > -static void __debugfs_remove_file(struct dentry *dentry, struct dentry *parent)
> > +static void __debugfs_file_removed(struct dentry *dentry)
> >  {
> >       struct debugfs_fsdata *fsd;
> >
> > -     simple_unlink(d_inode(parent), dentry);
> > -     d_delete(dentry);
>
> What happened to this call?  Why no unlinking anymore?
>
> > -
> >       /*
> >        * Paired with the closing smp_mb() implied by a successful
> >        * cmpxchg() in debugfs_file_get(): either
> > @@ -643,18 +640,9 @@ static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
> >       int ret = 0;
> >
> >       if (simple_positive(dentry)) {
> > -             dget(dentry);
> > -             if (!d_is_reg(dentry)) {
> > -                     if (d_is_dir(dentry))
> > -                             ret = simple_rmdir(d_inode(parent), dentry);
> > -                     else
> > -                             simple_unlink(d_inode(parent), dentry);
> > -                     if (!ret)
> > -                             d_delete(dentry);
> > -             } else {
> > -                     __debugfs_remove_file(dentry, parent);
> > -             }
> > -             dput(dentry);
> > +             ret = simple_remove(d_inode(parent), dentry);
> > +             if (d_is_reg(dentry))
>
> Can't dentry be gone here?  This doesn't seem to match the same pattern
> as before.
>
> What am I missing?
>

The grammatical change __debugfs_remove_file() => __debugfs_file_removed()
After change, the helper only does the post delete stuff.
simple_unlink() is now done inside simple_remove().
This debugfs patch depends on a patch that adds the simple_remove() helper.
sorry for not mentioning this explicitly.

Thanks,
Amir.