On Sat, Apr 04, 2020 at 08:25:21AM +0800, Liu Bo wrote:
[..]
> > +static int iomap_begin_upgrade_mapping(struct inode *inode, loff_t pos,
> > + loff_t length, unsigned flags,
> > + struct iomap *iomap)
> > +{
> > + struct fuse_inode *fi = get_fuse_inode(inode);
> > + struct fuse_dax_mapping *dmap;
> > + int ret;
> > +
> > + /*
> > + * Take exclusive lock so that only one caller can try to setup
> > + * mapping and others wait.
> > + */
> > + down_write(&fi->i_dmap_sem);
> > + dmap = fuse_dax_interval_tree_iter_first(&fi->dmap_tree, pos, pos);
> > +
> > + /* We are holding either inode lock or i_mmap_sem, and that should
> > + * ensure that dmap can't reclaimed or truncated and it should still
> > + * be there in tree despite the fact we dropped and re-acquired the
> > + * lock.
> > + */
> > + ret = -EIO;
> > + if (WARN_ON(!dmap))
> > + goto out_err;
> > +
> > + /* Maybe another thread already upgraded mapping while we were not
> > + * holding lock.
> > + */
> > + if (dmap->writable)
>
> oops, looks like it's still returning -EIO here, %ret should be zero.
>
Good catch. Will fix it.
Vivek
