When gfs2_setattr_size() fails, it calls gfs2_rs_delete(ip, NULL) to get
rid of any reservations the inode may have.  Instead, it should pass in
the inode's write count as the second parameter to allow
gfs2_rs_delete() to figure out if the inode has any writers left.

In a next step, there are two instances of gfs2_rs_delete(ip, NULL) left
where we know that there can be no other users of the inode.  Replace
those with gfs2_rs_deltree(&ip->i_res) to avoid the unnecessary write
count check.

With that, gfs2_rs_delete() is only called with the inode's actual write
count, so get rid of the second parameter.

Fixes: a097dc7e ("GFS2: Make rgrp reservations part of the gfs2_inode structure")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>