Hi,
On 10/01/17 10:14, Jan Kara wrote:
Hi,
On Tue 10-01-17 09:44:59, Steven Whitehouse wrote:
I had originally thought about calling the proposal "kernel/userland
interface", however that seemed a bit vague and management interfaces seems
like a better title since it is I hope a bit clearer of the kind of thing
that I'm thinking about in this case.
There are a number of possible sub-topics and I hope that I might find a few
more before LSF too. One is that of space management (we have statfs, but
currently no notifications for thresholds crossed etc., so everything is
polled. That is ok sometimes, but statfs can be expensive in the case of
distributed filesystems, if 100% accurate. We could just have ENOSPC
notifications for 100% full, or something more generic), another is state
transitions (is the fs running normally, or has it gone read
only/withdrawn/etc due to I/O errors?) and a further topic would be working
towards a common interface for fs statistics (at the moment each fs defines
their own interface). One potential implementation, at least for the first
two sub-topics, would be to use something along the lines of the quota
netlink interface, but since few ideas survive first contact with the
community at large, I'm throwing this out for further discussion and
feedback on whether this approach is considered the right way to go.
Assuming the topic is accepted, my intention would be to gather together
some additional sub-topics relating to fs management to go along with those
I mentioned above, and I'd be very interested to hear of any other issues
that could be usefully added to the list for discussion.
So this topic came up last year and probably the year before as well (heh,
I can even find some patches from 2011 [1]). I think the latest attempt at
what you suggest was here [2]. So clearly there's some interest in these
interfaces but not enough to actually drive anything to completion. So for
this topic to be useful, I think you need to go at least through the
patches in [2] and comments to them and have a concrete proposal that can
be discussed and some commitment (not necessarily from yourself) that
someone is going to devote time to implement it. Because generally nobody
seems to be opposed to the abstract idea but once it gets to the
implementation details, it is non-trivial to get some wider agreement
(statx anybody? ;)).
Honza
[1] https://lkml.org/lkml/2011/8/18/170
[2] https://lkml.org/lkml/2015/6/16/456
Yes, statx is something else I'd like to see progress too :-) Going back
to this topic though, I agree wrt having a concrete proposal, and I'll
try and have something ready for LSF, we have a few weeks in hand. I'll
collect up the details of the previous efforts (including Lukas'
suggestion) and see how far we can get in the mean time,
Steve.
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