[$] The ongoing quest for atomic buffered writes

There are many applications that need to be able to write multi-block
chunks of data to disk with the assurance that the operation will either
complete successfully or fail altogether — that the write will not be
partially completed (or “torn”), in other words. For years, kernel
developers have worked on providing atomic writes as a way of satisfying
that need; see, for example, sessions from the Linux Storage, Filesystem,
Memory Management, and BPF (LSFMM+BPF) Summit from 2023, 2024,
and 2025 (twice). While atomic direct I/O is now supported by some filesystems, atomic
buffered I/O still is not. Filling
that gap seems certain to be a 2026 LSFMM+BPF topic but, thanks to an early
discussion, the shape of a solution might already be coming into focus.