Re: EXT2_UNRM_FL
Richard Gooch (rgooch@atnf.csiro.au)
Thu, 4 Mar 1999 11:20:53 +1100
Theodore Y. Ts'o writes:
> Date: Thu, 4 Mar 1999 10:46:59 +1100
> From: Richard Gooch <rgooch@atnf.csiro.au>
>
> I don't understand why you even want to poll. My approach was to clean
> up at safe-delete time: I just do a stat(2) to see if there is enough
> space left. If not, I start purging. And in your ~/.logout you can
> call the command to empty the wastebasket.
> If you want to get more fancy, set up a cron job or add something to
> the boot scripts to clean up.
>
> Someone deletes a large number of files on the system. Sometime
> later, some other user starts unpacking a kernel tree, and needs
> space. It would be nice for a daemon to notice that free space was
> getting critical, and for it to start really deleted files that were
> in the "trashcan" in order to make space. After all, when the user
> deleted the files, they're effectively stating that they don't want
> them anymore, and the undelete option is just as a saving throw. If
> they then logout for three months, if the space is needed for
> something more worthy, there should be a way for that space to be
> reclaimed automatically.
I understand most of that, but I'm still missing why the polling is
needed. Why not have the utility check for low space, purge the user's
files and if space is still too low, contact the daemon to purge other
users' files?
With polling you preemptively purge. I'm suggesting that you only
purge when you run out of space.
Hm. Wait a minute. Now I see what you're driving at. You're referring
to the case where space is needed when putting new files on the
FS. OK. Yeah, regular polling by the daemon could be used to see if
you run out of space. Yep. Let's first see if a polling daemon is
effective before hacking the kernel. The cost of polling should be
really cheap, so doing it once a second or more should be OK.
Regards,
Richard....
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