On Mon, 03.01.11 09:54, Chris Adams (cmadams(a)hiwaay.net) wrote:
Once upon a time, Adam Jackson <ajax(a)redhat.com> said:
> Sadly this turns out not to be the case, at least if I'm reading
> fs/pipe.c correctly. O_NOATIME will turn off atime updates, but mtime
> and ctime are still modified on every pipe write, and there's no such
> thing as O_NOCMTIME even though the filesystem layer does have the
> concept internally. Which means device-backed filesystems will see
> write traffic just for using named pipes.
>
> Heck of lame. Someone should fix that.
The behavior follows the standard, so it shouldn't just be changed by
default without checking if anybody uses the standard behavior.
Well, I think introducing O_NOCTIME the same way O_NOATIME was
introduced would be unproblematic: only if it is set the normal ctime
behaviour would be disabled.
But yeah, I agree with ajax, the fact that the ctime of a fifo is
updated all the time and there is no way around it is kinda
ridiculous... And it gives the jack folks a really good reason not to
stick a fifo into /tmp.
Lennart
--
Lennart Poettering - Red Hat, Inc.