[$] Atomic writes for ext4

Building on the discussion in the two previous sessions on untorn (oratomic) writes, for buffered I/O and for XFS using direct I/O, Ojaswin Mujooremotely led asession on support for the feature on ext4. That took place in the combined storage andfilesystem track at the2025 Linux Storage, Filesystem, Memory Management, and BPF Summit. Part ofthe support for the feature is already in the upstream kernel, with morecoming. But there are still some challenges that Mujoo wanted to discuss.