From: Alexander Aring <aahringo@redhat.com>
To: Andreas Gruenbacher <agruenba@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 10:22:25 -0400 [thread overview]
Message-ID: <CAK-6q+i4YsSPX5i3zAUK5PX1XZ4JY_U=hhx-8N8mEeoOiRKw5g@mail.gmail.com> (raw)
In-Reply-To: <20240618160517.901589-12-agruenba@redhat.com>
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?
> -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?
- Alex
next prev parent reply other threads:[~2024-06-20 14:22 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 [this message]
2024-06-20 14:45 ` Andreas Gruenbacher
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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