Messages in this thread |  | | From | Neil Brown <> | Date | Tue, 30 Oct 2001 10:23:23 +1100 (EST) | Subject | Re: RFC - tree quotas for Linux (2.4.12, ext2) |
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On Monday October 29, jack@suse.cz wrote: > > > > I accept that it does look like a bit of a hack. > > But I think it is simple, understandable, and predictable. > > And I think that (for me) the value of tree quotas is more than enough > > to offset that cost. > I just don't like the idea that when you do lookup you can suddenly get > Disk quota exceeded... I'd concern this behaviour a bit nonintuitive. I agree > that if root makes lookup of every file after moving directories then this > doesn't happen but still I don't like the design :). >
You cannot get "Disk quota exceeded" on a lookup. If treequota_check finds a discrepancy it fixes it with "notify_change" with ia_valid set to ATTR_FORCE | ATTR_TID. I changed quota_transfer to take ATTR_FORCE to mean "just do it, even if it exceeds quota, and don't give an error". Given that ATTR_FORCE is not actually used at all in the current kernel, I felt fairly free to interpret it how I wanted.
So the only non-intuitive thing that can happen is that you find your usage mysteriously changes. However this can only happen after administrator intervention, and with uid quotas administrator intervention (e.g. chown -R) can equally cause mysterious changes of usage.
However I'm not particularly trying to convince anyone to use or approve of tree-quotas. I was after comments to make sure that I hadn't missed something in thinking through the issues. I thank you and others for your comments. The fact that I am comfortable with my answers (though you may not be) encourages me that I haven't missed anything.
I will be using treequotas locally next year and will keep the patches on my web-page up-to-date. I have heard from at least one person who thinks they might be useful, so there are probably a few dozen who might find it useful. In 6-12 months, if my experience is all positive, I might try suggesting that they get included in a "standard" kernel (assuming that 2.5 has openned by then:-).
Thanks again, NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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