On Thu, Jan 13, 2022 at 11:44:24AM +0100, Jan Kara wrote: > Maybe the most disputable thing in this locking chain seems to be splicing > from sysfs files. That does not seem terribly useful and due to special > locking and behavior of sysfs files it allows for creating interesting lock > dependencies. OTOH maybe there is someone out there who (possibly > inadvertedly through some library) ends up using splice on sysfs files so > chances for userspace breakage, if we disable splice for sysfs, would be > non-negligible. Hum, tough. People were using sendfile on sysfs files, that is why support for this got added back after it was removed for a while as part of the set_fs() removal. The real question for me is why do we need freeing and writer counts on sysfs or any other pure in-memory file system to start with?
