[$] Filesystems and iomap

The iomapblock-mapping abstraction is being used by more filesystems, in partbecause of its support for large folios. But there are some challenges inadopting iomap, which was the topic of a discussion led by Ritesh Harjaniin a combined storage and filesystem session at the 2024 Linux Storage,Filesystem, Memory Management, and BPF Summit. One of the main troublespots is how to handle metadata, which is not an area that iomap has been aimedat.