On Mon, Apr 08, 2013 at 11:23:14AM -0700, Jim Lieb wrote: > On Monday, April 08, 2013 10:42:02 J. Bruce Fields wrote: > > On Mon, Apr 08, 2013 at 01:36:46PM +0300, Boaz Harrosh wrote: > > > From: Jim Lieb <jlieb@xxxxxxxxxxx> > > > > > > In current NFS Server (Ganesha) lots of operation becomes 6 syscalls > > > (Or is it 7?) > > > > > > - setfsuid(), setfsgid(), thread_setgroups() > > > - The OP > > > - Revert setfsuid(), setfsgid() to root > > > > > > This is because if we do all these file operations as root then > > > FS will not account for the quota a user have on create files, > > > data space, and so on. > > > > To make sure I understand, you're saying that: > > > > - the behavior you get out of those 6 syscalls is correct, > > - you just want to be able to do exactly the same thing, but > > with 1 syscall. (For performance?) > > > > Or is there some other issue? > > I have attached the email I sent around on the nfs-ganesha list with a model > api so we know the details. > > Boaz replied "performance" but there are also race conditions to consider. If > we get signals or ??? somewhere in the sequence, what is our state? Yes, the > setfsuid call back to root can still be done but masquerading has any signals > etc. be in the context of that user/group and there is one syscall to deal > with, not a stream. Sorry, I don't understand what you're saying here. Could you give an example showing a sequence of events with the wrong result? > There may be selinux/apparmor issues to deal with too. If we first > masquerade the thread and then apply all these access checks, as far > as the kernel is concerned, it is the masqueraded user. I don't understand here either. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
