Hi Paul, thanks for the answer. I don't have a current glibc assignment, so me directly sending a patch is probably not productive. I don't really know which file systems benefit from doing a zeroing operations - after all this requires writing the data twice which usually actually is a bad idea unless offset by extremely suboptimal allocation behavior for small allocations, which got fixed in most file systems people actually use. So candidates where it actually would be useful might be things like hfsplus. But these are often used on cheap consumer media, where the double write will actually meaningfully cause additional write and erase cycle harming the device lifetime and long term performance. Note that the kernel has a few implementations of fallocate that are basically a slightly more optimized implementation of this pattern (fat, gfs2) so some maintainers through it useful at least for some workloads and use cases.
