[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] 9p file system for xen
On Mon, Nov 16, 2015 at 10:22:41AM -0700, Linda wrote: > > > On 11/16/2015 9:51 AM, Wei Liu wrote: > >On Mon, Nov 16, 2015 at 09:36:24AM -0700, Linda wrote: > >>Hi Wei, > >> > >>On 11/16/2015 8:16 AM, Wei Liu wrote: > >>>Hi Linda > >>> > >>>On Fri, Nov 13, 2015 at 10:23:22AM -0700, Linda wrote: > >>>>Hello, > >>>> I worked this summer as an intern under Julien Grall and Wei Liu. > >>>> My > >>>>project was to develop a prototype/proof of concept xen front/back end for > >>>>the 9p file system. I mostly hacked the virtio 9p system. > >>>> This project was not complete, at the end of the summer. Julien said > >>>>that you all wanted to include this in the next release of xen in January, > >>>>and offered to take it over. I told Julien I wanted to continue working > >>>>on > >>>>it, which I have been doing, very much in the background. > >>>> I came upon a bug in my code recently that made me aware that I am > >>>> not > >>>>clear what the expectation for what I deliver should be: i.e., whether > >>>>it's > >>>>still a prototype, or whether this should be production software. > >>>> Right now, I do not modify the toolstack (I never learned how), but > >>>>rather start and pause my guest, and then modify xenstore, manually. I > >>>>can > >>>>fix my bug in the same manner, but this will limit the usefulness of what > >>>>I > >>>>deliver. To do more will hit up against the limitations of my time and > >>>>knowledge. > >>>> So please let me know what you're expecting, especially wrt the user > >>>>interface, and when I would need to complete everything for this release. > >>>> > >>>If I interpret this correctly, you have a prototype that's working? Do > >>>you have your code somewhere? > >>No. I hit a bug that I would fix differently, depending on my goal. > >>>I think we would still like to include it in next release if possible -- > >>>that would require a properly implemented solution, not just a > >>>prototype. Let's assess the current situation and then decide what to > >>The situation is, given my current knowledge and what my availability has > >>been (it may improve), I can either: > >> a. Get a decent prototype working by the end of the year. This would > >>have certain values pre-written in xenstore, that I'm currently doing > >>manually. There are potentially some issues with mounting that I suspect > >>need to be different for xen than they are for virtio - so either way, I > >>need a clarification of how xen people want this to work. > >> b. Make sure what I've written is working, and pass it on to someone > >>else to update the toolstack, and resolve the issues, described above. In > >>this scenario, I would need to know how much time that someone would need > >>and just devote a week to getting this to them. > >> > >Your description is too vague. I don't have clear idea what kind of bug > >you encountered and what suggestion I can give. > The bug is a timing issue: During virtio's probe step, on the front end, it > initialized the mount path. Since at that time, the front end doesn't have > access to the back end's entries in xenstore (AFIACT), I either need to put > it in xenstore prior to starting, or move the access to this information to > later in the initialization. > > Note, I used the past tense on what virtio did, as of last summer: when I > looked at it last week, it appears to have changed since I first used it as > a template. I need to investigate this further. > OK. > Finally, I've made no provision for how to mount more than one file system > for the same guest. This is a feature that virtio provides for in the > front-end code (as do I), but I am unclear about how this works in the > back-end or at the user level. This is what I suspect will be different in > xen, and I'd like some input on what it should look like. I think this comes down to how your design the xenstore protocol to represent different mount points. > >The code freeze for next release is going to be end of March next year. > >As software engineer often overestimates the progress he or she can > >make, I would say we shall aim for getting something working as soon as > >possible. Get the design straight and something clean by the end of this > >year would be good. > Sounds good to me. I'm happy to keep working on this. I just didn't want > to find myself in a position where I needed to pass this on to someone else, > but I didn't give that person enough time to finish what I'd done. Depending on the situation, I can take over the code. You've done enough for this project and we don't really want you to work on it for free -- we don't have provision for more funding at the moment. If we end up taking over the project, we will still attribute the initial implementation to you. Wei. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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