Support for linux FUSE_SETXATTR_EXT

[jiefenghuang]

Hi, I'd like to inquire if there are any plans to support the extended feature FUSE_SETXATTR_EXT. Within ACLs, there's a need for the extra_flags FUSE_SETXATTR_ACL_KILL_SGID to determine whether to clear the sgid.

related linux patch: https://lore.kernel.org/linux-fsdevel/20210319195547.427371-1-vgoyal@redhat.com/

[hanwen]

I don't have plans, but will happily review a patch if someone produces it.