On Tue, Jul 10, 2018 at 06:05:49PM -0700, Linus Torvalds wrote: > Yeah, Andy is right that we should *not* make "write()" have side effects. > > Use it to queue things by all means, but not "do" things. Not unless > there's a very sane security model. > > On Tue, Jul 10, 2018 at 4:59 PM Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > > > > I think the right solution is one of: > > > > (a) Pass a netlink-formatted blob to fsopen() and do the whole thing in one syscall. I don’t mean using netlink sockets — just the nlattr format. Or you could use a different format. The part that matters is using just one syscall to do the whole thing. > > Please no. Not another nasty marshalling thing. > > > (b) Keep the current structure but use a new syscall instead of write(). > > > > (c) Keep using write() but literally just buffer the data. Then have a new syscall to commit it. In other words, replace “x” with a syscall and call all the fs_context_operations helpers in that context instead of from write(). > > But yeah, b-or-c sounds fine. Umm... How about "use credentials of opener for everything"?
