Merge pull request #8496 from athanatos/wip-15312

os/filestore: force lfn attrs to be written atomically, restructure name length limits

diff --cc src/common/config_opts.h
Simple merge

diff --cc src/os/ObjectStore.h
Simple merge

diff --cc src/osd/ReplicatedPG.cc
Simple merge

diff --cc src/test/librados/misc.cc
Simple merge