[fuse-devel] Using fgetattr highlevel API Vs. getattr lowlevel API

[Kobi Cohen-A. <kob...@gm...>]

Hi,

I'm trying to use fgetattr in highlevel API.

I started off using hello.c example and added hello_fgetattr.
The idea is to populate fi->fh in open call and use it in fgetattr for
opened file.

The problem is that fi->fh is always zero regardless to the value assigned
to it during the open call.
In do_getattr, inarg structure always looks like that: {getattr_flags = 1,
dummy = 0, fh = 0}.

The interesting part is that ll API is working w/o issues. i.e. I took
hello_ll.c, added hello_ll_getattr, and populate fh in open the same way in
hello.c.
I can see hello_ll_getattr is getting the correct fh values in do_getattr().

I might be missing something here, but it seems to me that lowlevel and
highlevel should work the same in that case:
In the kernel code I can see fs/fuse/dir.c has the following in
fuse_create_open():

ff->fh = outopen.fh;
…
file->private_data = fuse_file_get(ff);

Now, in the same file, func fuse_do_getattr():
   if (file && S_ISREG(inode->i_mode)) {
        struct fuse_file *ff = file->private_data;
                inarg.getattr_flags |= FUSE_GETATTR_FH;
                inarg.fh = ff->fh;
    }

So I guess that part is a common code between ll and hl API. So I would
expect do_getattr would behave the same:

       struct fuse_getattr_in *arg = (struct fuse_getattr_in *) inarg;
        if (arg->getattr_flags & FUSE_GETATTR_FH) {
             memset(&fi, 0, sizeof(fi));
             fi.fh = arg->fh; // arg->fh is always 0
             fi.fh_old = fi.fh;
             fip = &fi;
        }

But doesn't. Any idea why hl API would be missing fh ?

Thanks in advance,
- Kobi