Just for reference attached are two patches that implement support for
Q_GETNEXTQUOTA and Q_XGETNEXTQUOTA in quota-tools. I have used it for
testing XFS and VFS infrastructure for these new quotactls.
Honza
On Fri 22-01-16 12:25:29, Eric Sandeen wrote:
> This adds a new quotactl, Q_GETNEXTQUOTA.
>
> Q_GETNEXTQUOTA is exactly like Q_GETQUOTA, except that it will
> return quota information for the id equal to or greater than
> the id requested. In other words, if the specified id has
> no quota, the command will return quota information for the
> next higher id which does have a quota set. If no higher id
> has an active quota, -ESRCH is returned.
>
> So if you ask for id X, you can get back quota for id X,
> id X+N, or -ESRCH if no higher id has a quota.
>
> This allows filesystems to do efficient iteration in kernelspace,
> much like extN filesystems do in userspace when asked to report
> all active quotas.
>
> Today, filesystems such as XFS require getpwent()-style iterations,
> and for systems which have i.e. LDAP backends, this can be very
> slow, or even impossible if iteration is not allowed in the
> configuration.
>
> Patches 1 and 4 are just small fixups that turned up along the way;
> 2 and 3 add the actual quota plumbing, and the rest are xfs-specific
> to allow xfs to support this new interface.
>
> For non-xfs quota, this does require a new structure which is
> able to pass back the discovered ID along with the quota info.
> For xfs-quota, the id is already present in the structure.
>
> V3:
> * Remove 32-bit compat stuff (i686/x86_64 at least works w/o it...)
> * Require CAP_SYS_ADMIN for these calls
> * Pass back found ID in &qid passed to ->get_nextdqblk, rather
> than modifying struct qc_dqblk
> * Munge that found ID back through user-namespace conversions
> before returning it in the user structure.
>
> Thanks,
> -Eric
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
0001-Scan-dquots-using-Q_GETNEXTQUOTA.patch
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0002-Add-support-for-scanning-using-Q_XGETNEXTQUOTA.patch
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