On Fri, Jul 18, 2025 at 04:27:50PM +0200, Amir Goldstein wrote:
> On Fri, Jul 18, 2025 at 1:36 AM Darrick J. Wong <djwong@xxxxxxxxxx> wrote:
> >
> > From: Darrick J. Wong <djwong@xxxxxxxxxx>
> >
> > Create a new ->getattr_iflags function so that iomap filesystems can set
> > the appropriate in-kernel inode flags on instantiation.
> >
> > Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
<snip for brevity>
> > diff --git a/lib/fuse.c b/lib/fuse.c
> > index 8dbf88877dd37c..685d0181e569d0 100644
> > --- a/lib/fuse.c
> > +++ b/lib/fuse.c
> > @@ -3710,14 +3832,19 @@ static int readdir_fill_from_list(fuse_req_t req, struct fuse_dh *dh,
> > if (de->flags & FUSE_FILL_DIR_PLUS &&
> > !is_dot_or_dotdot(de->name)) {
> > res = do_lookup(dh->fuse, dh->nodeid,
> > - de->name, &e);
> > + de->name, &e, &iflags);
> > if (res) {
> > dh->error = res;
> > return 1;
> > }
> > }
> >
> > - thislen = fuse_add_direntry_plus(req, p, rem,
> > + if (f->want_iflags)
> > + thislen = fuse_add_direntry_plus_iflags(req, p,
> > + rem, de->name, iflags,
> > + &e, pos);
> > + else
> > + thislen = fuse_add_direntry_plus(req, p, rem,
> > de->name, &e, pos);
>
>
> All those conditional statements look pretty moot.
> Can't we just force iflags to 0 if (!f->want_iflags)
> and always call the *_iflags functions?
Heh, it already is zero, so yes, this could be a straight call to
fuse_add_direntry_plus_iflags without the want_iflags check. Will fix
up this and the other thing you mentioned in the previous patch.
Thanks for the code review!
Having said that, the significant difficulties with iomap and the
upper level fuse library still exist. To summarize -- upper libfuse has
its own nodeids which don't necssarily correspond to the filesystem's,
and struct node/nodeid are duplicated for hardlinked files. As a
result, the kernel has multiple struct inodes for an ondisk ext4 inode,
which completely breaks the locking for the iomap file IO model.
That forces me to port fuse2fs to the lowlevel library, so I might
remove the lib/fuse.c patches entirely. Are there plans to make the
upper libfuse handle hardlinks better?
--D
> Thanks,
> Amir.
>
