Re: Oops: Quota race in 2.4.12?

Jan Kara (jack@suse.cz)
Tue, 30 Oct 2001 13:14:31 +0100


Hello,

> On Sunday October 28, sim@netnation.com wrote:
> > Some of our dual CPU web servers with 2.4.12 are Oopsing while running
> > quotacheck. They don't seem to die immediately, but oops many times and
> > eventually break. The old tools didn't warn about quotachecking on a
> > live file system, so some of our servers were set up to run quotacheck
> > nightly. The new tools still allow you to do it, but warn that it may
> > not be consistent. We didn't have any problems with 2.2 kernels.
>
> quotacheck cannot be reliable on a live system as it scans through the
> filesystem counting the usage for each user and then updates the
> quotas file. If usage changes between scanning a file and updating
> the quota record, you get an error. This is particularly a problem
> if quotacheck takes a long time, and on one of my servers (heavily
> loaded NFS server) quotacheck takes a *long* time if the server is
> live (it isn't exactly quick if it isn't live either).
>
> I wrote a little program which uses libext2fs to scan the block device
> for inodes and add up usage that way (as opposed to walking the
> filetree as I believe quotacheck does). It runs *much* faster
> (minutes instead of hours).
Note that quotacheck(8) uses e2fslib too if compiled properly...

Honza

>
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