[$] Supporting NFS v4.2 WRITE_SAME

At the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit
(LSFMM+BPF), Anna Schumaker led a discussion about implementing the NFS
v4.2 WRITE_SAME
command
in both the NFS client and server. WRITE_SAME is
meant to write large amounts of identical data (e.g. zeroes) to the server
without actually needing to transfer all of it over the wire. In her topic
proposal
, Schumaker wondered whether other filesystems needed the
functionality, so that it should be implemented at the virtual filesystem
(VFS) layer, or whether it should simply be handled as an NFS-specific ioctl().