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 75F41C677F1 for ; Mon, 16 Jan 2023 16:46:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233727AbjAPQqD (ORCPT ); Mon, 16 Jan 2023 11:46:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233615AbjAPQpd (ORCPT ); Mon, 16 Jan 2023 11:45:33 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E5C8298DD for ; Mon, 16 Jan 2023 08:33:04 -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 dfw.source.kernel.org (Postfix) with ESMTPS id A63AA61077 for ; Mon, 16 Jan 2023 16:33:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB4CEC433D2; Mon, 16 Jan 2023 16:33:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673886783; bh=K3Z/voQ6voqtb0S8pqAhrrojJQY4E6tYR2H3+PP6jXg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q/RaP5IcCx6EQuZ0QdGRzZ7tiprGlsZxAQpH5qziOyiQWYmWRj2uIoB/O0UAAnx/t NmAgA8bMK+43xu69C20a9RxHSXvzATCX5nAUWKuGrwRipeUrvAS4Htl1XMCIO9eVqU VN7DtOSgjGAsooRXEZaOPP5lQX++PiGF2Bn2ICSQ= 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 5.4 561/658] mbcache: dont reclaim used entries Date: Mon, 16 Jan 2023 16:50:49 +0100 Message-Id: <20230116154935.162723413@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@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 97c54d3a2227..cfc28129fb6f 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -288,7 +288,7 @@ 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; @@ -302,6 +302,14 @@ 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