[$] Disabling an extent optimization

In the final filesystem session at the2022 Linux Storage,Filesystem, Memory-management and BPF Summit (LSFMM), David Howells leda discussion on a filesystem optimization that is causing various kinds ofproblems. Extent-based filesystems have data structures that sometimes donot reflect the holes that exist in files. Reads from holes in sparse files (i.e. files withholes) must return zeroes, but filesystems are not obligated to maintain knowledge ofthe holes beyond that, which leads to the problems.

This concludes our coverage of LSFMM 2022.