From mboxrd@z Thu Jan 1 00:00:00 1970 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 BF816C67871 for ; Mon, 16 Jan 2023 17:16:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234497AbjAPRQP (ORCPT ); Mon, 16 Jan 2023 12:16:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234375AbjAPRPa (ORCPT ); Mon, 16 Jan 2023 12:15:30 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83EFB2BF15 for ; Mon, 16 Jan 2023 08:56:32 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3C446B81091 for ; Mon, 16 Jan 2023 16:56:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89989C433D2; Mon, 16 Jan 2023 16:56:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673888189; bh=NYJGUI48HmVEox1bjKoxb7G7llrjMujfRYggdsXKVng=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PuGONg2XpMe7/QxeMubymoylvAeH79T+6p1O23XmMm8pxQxBu0d6T3LfylshGBgWf Ta7wCo0QWhYMzIM8QWaY0EAEpRSyOfNRAjy0i+YwGgqgMa74nah3SWx6oN0VslkjfZ wybVZBFGOykQHkQ+Lv4nksKZUl8xK5pj86zzHq94= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jan Kara , Theodore Tso , Sasha Levin Subject: [PATCH 4.19 435/521] mbcache: dont reclaim used entries Date: Mon, 16 Jan 2023 16:51:37 +0100 Message-Id: <20230116154906.599829443@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154847.246743274@linuxfoundation.org> References: <20230116154847.246743274@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Kara [ Upstream commit 58318914186c157477b978b1739dfe2f1b9dc0fe ] Do not reclaim entries that are currently used by somebody from a shrinker. Firstly, these entries are likely useful. Secondly, we will need to keep such entries to protect pending increment of xattr block refcount. CC: stable@vger.kernel.org Fixes: 82939d7999df ("ext4: convert to mbcache2") Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220712105436.32204-1-jack@suse.cz Signed-off-by: Theodore Ts'o Stable-dep-of: a44e84a9b776 ("ext4: fix deadlock due to mbcache entry corruption") Signed-off-by: Sasha Levin --- fs/mbcache.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/mbcache.c b/fs/mbcache.c index 081ccf0caee3..12203e5a91e7 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -287,7 +287,7 @@ static unsigned long mb_cache_shrink(struct mb_cache *cache, while (nr_to_scan-- && !list_empty(&cache->c_list)) { entry = list_first_entry(&cache->c_list, struct mb_cache_entry, e_list); - if (entry->e_referenced) { + if (entry->e_referenced || atomic_read(&entry->e_refcnt) > 2) { entry->e_referenced = 0; list_move_tail(&entry->e_list, &cache->c_list); continue; @@ -301,6 +301,14 @@ static unsigned long mb_cache_shrink(struct mb_cache *cache, spin_unlock(&cache->c_list_lock); head = mb_cache_entry_head(cache, entry->e_key); hlist_bl_lock(head); + /* Now a reliable check if the entry didn't get used... */ + if (atomic_read(&entry->e_refcnt) > 2) { + hlist_bl_unlock(head); + spin_lock(&cache->c_list_lock); + list_add_tail(&entry->e_list, &cache->c_list); + cache->c_entry_count++; + continue; + } if (!hlist_bl_unhashed(&entry->e_hash_list)) { hlist_bl_del_init(&entry->e_hash_list); atomic_dec(&entry->e_refcnt); -- 2.35.1