On Sun, Apr 22, 2018 at 08:06:30AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Quotacheck only runs during mount, which means that there are no other
> processes in the system that could be doing chown or chproj. Therefore
> there's no potential for racing to attach dquots to the inode so we can
> drop all the ILOCK and race detection bits from quotacheck.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/xfs_qm.c | 28 ++++++++++++----------------
> 1 file changed, 12 insertions(+), 16 deletions(-)
>
>
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index 385d315..123ea5f 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -1065,16 +1065,17 @@ xfs_qm_dqiterate(
> STATIC int
> xfs_qm_quotacheck_dqadjust(
> struct xfs_inode *ip,
> - xfs_dqid_t id,
> uint type,
> xfs_qcnt_t nblks,
> xfs_qcnt_t rtblks)
> {
> struct xfs_mount *mp = ip->i_mount;
> struct xfs_dquot *dqp;
> + xfs_dqid_t id;
> int error;
>
> - error = xfs_qm_dqget_inode(mp, ip, type, XFS_QMOPT_DQALLOC, &dqp);
> + id = xfs_qm_id_for_quotatype(ip, type);
> + error = xfs_qm_dqget(mp, id, type, XFS_QMOPT_DQALLOC, &dqp);
> if (error) {
> /*
> * Shouldn't be able to turn off quotas here.
> @@ -1147,13 +1148,10 @@ xfs_qm_dqusage_adjust(
> }
>
> /*
> - * We don't _need_ to take the ilock EXCL. However, the xfs_qm_dqget
> - * interface expects the inode to be exclusively locked because that's
> - * the case in all other instances. It's OK that we do this because
> - * quotacheck is done only at mount time.
> + * We don't _need_ to take the ilock EXCL here because quotacheck runs
> + * at mount time and therefore nobody will be racing chown/chproj.
> */
> - error = xfs_iget(mp, NULL, ino, XFS_IGET_DONTCACHE, XFS_ILOCK_EXCL,
> - &ip);
> + error = xfs_iget(mp, NULL, ino, XFS_IGET_DONTCACHE, 0, &ip);
> if (error) {
> *res = BULKSTAT_RV_NOTHING;
> return error;
> @@ -1188,33 +1186,31 @@ xfs_qm_dqusage_adjust(
> * and quotaoffs don't race. (Quotachecks happen at mount time only).
> */
> if (XFS_IS_UQUOTA_ON(mp)) {
> - error = xfs_qm_quotacheck_dqadjust(ip, ip->i_d.di_uid,
> - XFS_DQ_USER, nblks, rtblks);
> + error = xfs_qm_quotacheck_dqadjust(ip, XFS_DQ_USER, nblks,
> + rtblks);
> if (error)
> goto error0;
> }
>
> if (XFS_IS_GQUOTA_ON(mp)) {
> - error = xfs_qm_quotacheck_dqadjust(ip, ip->i_d.di_gid,
> - XFS_DQ_GROUP, nblks, rtblks);
> + error = xfs_qm_quotacheck_dqadjust(ip, XFS_DQ_GROUP, nblks,
> + rtblks);
> if (error)
> goto error0;
> }
>
> if (XFS_IS_PQUOTA_ON(mp)) {
> - error = xfs_qm_quotacheck_dqadjust(ip, xfs_get_projid(ip),
> - XFS_DQ_PROJ, nblks, rtblks);
> + error = xfs_qm_quotacheck_dqadjust(ip, XFS_DQ_PROJ, nblks,
> + rtblks);
> if (error)
> goto error0;
> }
>
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> IRELE(ip);
> *res = BULKSTAT_RV_DIDONE;
> return 0;
>
> error0:
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> IRELE(ip);
> *res = BULKSTAT_RV_GIVEUP;
> return error;
>
> --
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