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 DF6FDC25B50 for ; Fri, 20 Jan 2023 19:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229941AbjATTwU (ORCPT ); Fri, 20 Jan 2023 14:52:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229645AbjATTwT (ORCPT ); Fri, 20 Jan 2023 14:52:19 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 543E8BB96; Fri, 20 Jan 2023 11:52:18 -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 E006D6206D; Fri, 20 Jan 2023 19:52:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A029CC433EF; Fri, 20 Jan 2023 19:52:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674244337; bh=6jPk4/xopHMScMSF0b0LFfVr32gVbdEpBA+awgkZELo=; h=From:To:Cc:Subject:Date:From; b=jMBjJPTKclEPTTQKAp4VCZr3bgTnKC4OuMDd0uIzEIiB82PH2+ossDtRZRHOGTmVr L0+/iouxOH07R9zP7rBrptUhD82E0Yqn1EwrKjjcrmqWk3lIw+HQzvtQiUBPwNuleN icBgcQRsggoh0eqket2S67OQcpA672u0mEwOzr69Xc2vSv6zA+U7+cMPzG7kN78ALy dgzVEALHVFz34A1VdkHWuR71/SnXGu5Pn9wily6zYwh7v5PtX2MwqdJ+M7hNFghX2S 7hqunNs9hEV/rKaU33c6sPAGcpSKreZkDx2alyMN34/2urwFOavcqXaT23d8jpYzda BXJ7WXFUl+MUQ== From: Jeff Layton To: Chuck Lever Cc: Ruben Vestergaard , Torkil Svensgaard , Shachar Kagan , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] nfsd: don't free files unconditionally in __nfsd_file_cache_purge Date: Fri, 20 Jan 2023 14:52:14 -0500 Message-Id: <20230120195215.42243-1-jlayton@kernel.org> X-Mailer: git-send-email 2.39.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org nfsd_file_cache_purge is called when the server is shutting down, in which case, tearing things down is generally fine, but it also gets called when the exports cache is flushed. Instead of walking the cache and freeing everything unconditionally, handle it the same as when we have a notification of conflicting access. Fixes: ac3a2585f018 ("nfsd: rework refcounting in filecache") Reported-by: Ruben Vestergaard Reported-by: Torkil Svensgaard Reported-by: Shachar Kagan Signed-off-by: Jeff Layton --- fs/nfsd/filecache.c | 61 +++++++++++++++++++++++++++------------------ 1 file changed, 37 insertions(+), 24 deletions(-) v2: use the same method to purge entries from the cache as we do when there is a notification of conflicting access. diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index 58ac93e7e680..397ae212b98d 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -661,6 +661,40 @@ static struct shrinker nfsd_file_shrinker = { .seeks = 1, }; +/** + * maybe_queue_nfsd_file - try to unhash and queue a nfsd_file to be freed + * @nf: nfsd_file to attempt to queue + * @dispose: private list to queue successfully-put objects + * + * Unhash an nfsd_file, try to get a reference to it, and then put that + * reference. If it's the last reference, queue it to the dispose list. + * + * The caller MUST hold the rcu_read_lock() ! + */ +static void +maybe_queue_nfsd_file(struct nfsd_file *nf, struct list_head *dispose) +{ + int decrement = 1; + + /* If we raced with someone else unhashing, ignore it */ + if (!nfsd_file_unhash(nf)) + return; + + /* If we can't get a reference, ignore it */ + if (!nfsd_file_get(nf)) + return; + + /* Extra decrement if we remove from the LRU */ + if (nfsd_file_lru_remove(nf)) + ++decrement; + + /* If refcount goes to 0, then put on the dispose list */ + if (refcount_sub_and_test(decrement, &nf->nf_ref)) { + list_add(&nf->nf_lru, dispose); + trace_nfsd_file_closing(nf); + } +} + /** * nfsd_file_queue_for_close: try to close out any open nfsd_files for an inode * @inode: inode on which to close out nfsd_files @@ -688,30 +722,12 @@ nfsd_file_queue_for_close(struct inode *inode, struct list_head *dispose) rcu_read_lock(); do { - int decrement = 1; - nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key, nfsd_file_rhash_params); if (!nf) break; - /* If we raced with someone else unhashing, ignore it */ - if (!nfsd_file_unhash(nf)) - continue; - - /* If we can't get a reference, ignore it */ - if (!nfsd_file_get(nf)) - continue; - - /* Extra decrement if we remove from the LRU */ - if (nfsd_file_lru_remove(nf)) - ++decrement; - - /* If refcount goes to 0, then put on the dispose list */ - if (refcount_sub_and_test(decrement, &nf->nf_ref)) { - list_add(&nf->nf_lru, dispose); - trace_nfsd_file_closing(nf); - } + maybe_queue_nfsd_file(nf, dispose); } while (1); rcu_read_unlock(); } @@ -928,11 +944,8 @@ __nfsd_file_cache_purge(struct net *net) nf = rhashtable_walk_next(&iter); while (!IS_ERR_OR_NULL(nf)) { - if (!net || nf->nf_net == net) { - nfsd_file_unhash(nf); - nfsd_file_lru_remove(nf); - list_add(&nf->nf_lru, &dispose); - } + if (!net || nf->nf_net == net) + maybe_queue_nfsd_file(nf, &dispose); nf = rhashtable_walk_next(&iter); } -- 2.39.0