From nobody Mon Feb 9 08:29:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4429EB64D7 for ; Fri, 30 Jun 2023 11:11:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232816AbjF3LLA (ORCPT ); Fri, 30 Jun 2023 07:11:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232361AbjF3LKv (ORCPT ); Fri, 30 Jun 2023 07:10:51 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 693D8198E; Fri, 30 Jun 2023 04:10:50 -0700 (PDT) Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Qst050Q3SzqV8f; Fri, 30 Jun 2023 19:10:29 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Fri, 30 Jun 2023 19:10:48 +0800 From: Baokun Li To: CC: , , , , , , , Subject: [PATCH v3 5/5] quota: simplify drop_dquot_ref() Date: Fri, 30 Jun 2023 19:08:22 +0800 Message-ID: <20230630110822.3881712-6-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230630110822.3881712-1-libaokun1@huawei.com> References: <20230630110822.3881712-1-libaokun1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpeml500021.china.huawei.com (7.185.36.21) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" As Honza said, remove_inode_dquot_ref() currently does not release the last dquot reference but instead adds the dquot to tofree_head list. This is because dqput() can sleep while dropping of the last dquot reference (writing back the dquot and calling ->release_dquot()) and that must not happen under dq_list_lock. Now that dqput() queues the final dquot cleanup into a workqueue, remove_inode_dquot_ref() can call dqput() unconditionally and we can significantly simplify it. Here we open code the simplified code of remove_inode_dquot_ref() into remove_dquot_ref() and remove the function put_dquot_list() which is no longer used. Signed-off-by: Baokun Li --- V2->V3: Added changelog provided by Jan Kara (thanks Jan). Merge the patch that removed put_dquot_list() to the current patch. Open code Simplified remove_inode_dquot_ref() code to remove_dquot_ref(). fs/quota/dquot.c | 70 +++++++----------------------------------------- 1 file changed, 9 insertions(+), 61 deletions(-) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index c7afe433d991..e8232242dd34 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -1072,59 +1072,7 @@ static int add_dquot_ref(struct super_block *sb, int= type) return err; } =20 -/* - * Remove references to dquots from inode and add dquot to list for freeing - * if we have the last reference to dquot - */ -static void remove_inode_dquot_ref(struct inode *inode, int type, - struct list_head *tofree_head) -{ - struct dquot **dquots =3D i_dquot(inode); - struct dquot *dquot =3D dquots[type]; - - if (!dquot) - return; - - dquots[type] =3D NULL; - if (list_empty(&dquot->dq_free)) { - /* - * The inode still has reference to dquot so it can't be in the - * free list - */ - spin_lock(&dq_list_lock); - list_add(&dquot->dq_free, tofree_head); - spin_unlock(&dq_list_lock); - } else { - /* - * Dquot is already in a list to put so we won't drop the last - * reference here. - */ - dqput(dquot); - } -} - -/* - * Free list of dquots - * Dquots are removed from inodes and no new references can be got so we a= re - * the only ones holding reference - */ -static void put_dquot_list(struct list_head *tofree_head) -{ - struct list_head *act_head; - struct dquot *dquot; - - act_head =3D tofree_head->next; - while (act_head !=3D tofree_head) { - dquot =3D list_entry(act_head, struct dquot, dq_free); - act_head =3D act_head->next; - /* Remove dquot from the list so we won't have problems... */ - list_del_init(&dquot->dq_free); - dqput(dquot); - } -} - -static void remove_dquot_ref(struct super_block *sb, int type, - struct list_head *tofree_head) +static void remove_dquot_ref(struct super_block *sb, int type) { struct inode *inode; #ifdef CONFIG_QUOTA_DEBUG @@ -1141,11 +1089,16 @@ static void remove_dquot_ref(struct super_block *sb= , int type, */ spin_lock(&dq_data_lock); if (!IS_NOQUOTA(inode)) { + struct dquot **dquots =3D i_dquot(inode); + struct dquot *dquot =3D dquots[type]; + #ifdef CONFIG_QUOTA_DEBUG if (unlikely(inode_get_rsv_space(inode) > 0)) reserved =3D 1; #endif - remove_inode_dquot_ref(inode, type, tofree_head); + dquots[type] =3D NULL; + if (dquot) + dqput(dquot); } spin_unlock(&dq_data_lock); } @@ -1162,13 +1115,8 @@ static void remove_dquot_ref(struct super_block *sb,= int type, /* Gather all references from inodes and drop them */ static void drop_dquot_ref(struct super_block *sb, int type) { - LIST_HEAD(tofree_head); - - if (sb->dq_op) { - remove_dquot_ref(sb, type, &tofree_head); - synchronize_srcu(&dquot_srcu); - put_dquot_list(&tofree_head); - } + if (sb->dq_op) + remove_dquot_ref(sb, type); } =20 static inline --=20 2.31.1