On Tue, Jan 14, 2020 at 9:58 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> On Tue, Jan 14, 2020 at 9:19 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Tue, Jan 14, 2020 at 08:06:56PM +0200, Amir Goldstein wrote:
> > > > // NOTE: release_dentry_name_snapshot() will be needed for both copies.
> > > > clone_name_snapshot(struct name_snapshot *to, const struct name_snapshot *from)
> > > > {
> > > > to->name = from->name;
> > > > if (likely(to->name.name == from->inline_name)) {
> > > > memcpy(to->inline_name, from->inline_name,
> > > > to->name.len);
> > > > to->name.name = to->inline_name;
> > > > } else {
> > > > struct external_name *p;
> > > > p = container_of(to->name.name, struct external_name, name[0]);
> > > > atomic_inc(&p->u.count);
> > > > }
> > > > }
> > > >
> > > > and be done with that. Avoids any extensions or tree-wide renamings, etc.
> > >
> > > I started with something like this but than in one of the early
> > > revisions I needed
> > > to pass some abstract reference around before cloning the name into the event,
> > > but with my current patches I can get away with a simple:
> > >
> > > if (data_type == FANOTIFY_EVENT_NAME)
> > > clone_name_snapshot(&event->name, data);
> > > else if (dentry)
> > > take_dentry_name_snapshot(&event->name, dentry);
> > >
> > > So that simple interface should be good enough for my needs.
> >
> > I really think it would be safer that way; do you want me to throw that into
> > vfs.git (#work.dcache, perhaps)? I don't have anything going on in the
> > vicinity, so it's not likely to cause conflicts either way and nothing I'd
> > seen posted on fsdevel seems to be likely to step into it, IIRC, so...
> > Up to you.
>
> Sure, that would be great.
>
Only problem I forgot about is that I need to propagate name_snapshot
into fsnotify_move() instead of qstr (in order to snapshot it).
That means I will need to snapshot also new_dentry in vfs_rename(), so
I have a name_snapshot to pass into the RENAME_EXCHANGE
fsnotify_move() hook.
My current patch passes the cute &old_dentry->d_name_snap abstract
to fsnotify_move().
What shall I do about that?
take_dentry_name_snapshot(&new_name, new_dentry);
???
Thanks,
Amir.
