We used to have GFP_KERNEL kmalloc() done by the code that held hpfs
lock on directory.  That could trigger a call of hpfs_write_inode() and
deadlock; fixed by switch to GFP_NOFS.  Same for hpfs inodes themselves
- hpfs_write_inode() calls iget() and that could trigger both the
deadlocks (avoidable with very baroque locking scheme) and stack
overflows (unavoidable unless we kill potential recursion here).