From: Andreas Gruenbacher <agruenba@redhat.com>
To: Alexander Aring <aahringo@redhat.com>
Cc: gfs2@lists.linux.dev
Subject: Re: [PATCH 11/13] gfs2: Get rid of some unnecessary quota locking
Date: Thu, 20 Jun 2024 16:45:44 +0200 [thread overview]
Message-ID: <CAHc6FU4uYipHx6frNK2uCRuWjouKsTbr_6N=cJ52PPa+A3i-wg@mail.gmail.com> (raw)
In-Reply-To: <CAK-6q+i4YsSPX5i3zAUK5PX1XZ4JY_U=hhx-8N8mEeoOiRKw5g@mail.gmail.com>
On Thu, Jun 20, 2024 at 4:24 PM Alexander Aring <aahringo@redhat.com> wrote:
> Hi,
>
> On Tue, Jun 18, 2024 at 12:13 PM Andreas Gruenbacher
> <agruenba@redhat.com> wrote:
> >
> > With the locking the previous patch has introduced for each struct
> > gfs2_quota_data object, sd_quota_mutex has become largely irrelevant.
> > By waiting on the buffer head instead of waiting on the mutex in
> > get_bh(), it becomes completely irrelevant and can be removed.
> >
> ...
> > error = -EIO;
> > if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_QC))
> > - goto fail_brelse;
> > -
> > - qd->qd_bh = bh;
> > - qd->qd_bh_qc = (struct gfs2_quota_change *)
> > - (bh->b_data + sizeof(struct gfs2_meta_header) +
> > - offset * sizeof(struct gfs2_quota_change));
> > -
> > - mutex_unlock(&sdp->sd_quota_mutex);
> > + goto out;
> >
> > - return 0;
> > + spin_lock(&qd->qd_lockref.lock);
> > + if (qd->qd_bh == NULL) {
> > + qd->qd_bh = bh;
> > + qd->qd_bh_qc = (struct gfs2_quota_change *)
> > + (bh->b_data + sizeof(struct gfs2_meta_header) +
> > + offset * sizeof(struct gfs2_quota_change));
> > + bh = NULL;
>
> here you set bh to NULL.
>
> > + }
> > + qd->qd_bh_count++;
> > + spin_unlock(&qd->qd_lockref.lock);
> > + error = 0;
> >
> > -fail_brelse:
> > +out:
> > brelse(bh);
>
> It might be called with bh == NULL?
Yes, brelse() can handle that.
> > -fail:
> > - qd->qd_bh_count--;
> > - mutex_unlock(&sdp->sd_quota_mutex);
> > return error;
> > }
> >
> > static void bh_put(struct gfs2_quota_data *qd)
> > {
> > struct gfs2_sbd *sdp = qd->qd_sbd;
> > + struct buffer_head *bh = NULL;
> >
> > - mutex_lock(&sdp->sd_quota_mutex);
> > + spin_lock(&qd->qd_lockref.lock);
> > gfs2_assert(sdp, qd->qd_bh_count);
> > if (!--qd->qd_bh_count) {
> > - brelse(qd->qd_bh);
> > + bh = qd->qd_bh;
> > qd->qd_bh = NULL;
> > qd->qd_bh_qc = NULL;
> > }
> > - mutex_unlock(&sdp->sd_quota_mutex);
> > + spin_unlock(&qd->qd_lockref.lock);
> > +
> > + if (bh)
> > + brelse(bh);
>
> Here you care about that bh is != NULL.
>
> is breise() now NULL proofed?
Yes, always has been. I'll remove that unnecessary NULL check.
Thanks,
Andreas
next prev parent reply other threads:[~2024-06-20 14:46 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-18 16:05 [PATCH 00/13] gfs2: quota changes Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 01/13] gfs2: Minor gfs2_quota_init error path cleanup Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 02/13] gfs2: Check quota consistency on mount Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 03/13] gfs2: Revert "introduce qd_bh_get_or_undo" Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 04/13] gfs2: qd_check_sync cleanups Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 05/13] gfs2: Revert "ignore negated quota changes" Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 06/13] gfs2: Revert "Add quota_change type" Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 07/13] gfs2: Fix and clean up function do_qc Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 08/13] gfs2: quota need_sync cleanup Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 09/13] gfs2: Fold qd_fish into gfs2_quota_sync Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 10/13] gfs2: Add some missing quota locking Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 11/13] gfs2: Get rid of some unnecessary " Andreas Gruenbacher
2024-06-20 14:22 ` Alexander Aring
2024-06-20 14:45 ` Andreas Gruenbacher [this message]
2024-06-18 16:05 ` [PATCH 12/13] gfs2: Be more careful with the quota sync generation Andreas Gruenbacher
2024-06-18 16:05 ` [PATCH 13/13] gfs2: Revert "check for no eligible quota changes" Andreas Gruenbacher
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