Hello, Did you have a look at Shengyu Zhang's work on xattr? That's about summer 2016. Also see glibc/sysdeps/mach/hurd/setxattr.c which translates gnu attributes into RPC calls, and then again in the translators's diskfs_set_translator. See for instance in hurd/ext2fs/inode.c's diskfs_set_translator, it looks at
if (EXT2_HAS_COMPAT_FEATURE (sblock, EXT2_FEATURE_COMPAT_EXT_ATTR) && use_xattr_translator_records) Samuel