From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9881F28F3 for ; Mon, 30 Jan 2023 14:05:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2110C4339C; Mon, 30 Jan 2023 14:05:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675087529; bh=JiadrZOK1rKEMD3JOP8CbdUEDzY3eFYXUhac1tDo3ZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W5z55nW+t5RltS6tYvjX9y0aWBDJwhf1UwXdHTMnltA+DX6BGgCXexpEKDHQ4tD0K DCa0faZnPh1qOwnnnXKitXZ/d5UWYYa1uVOnXB5NjmOteUnSpPRaGNmAf4tAxIzejY w9C/MlFl4k6bhF8VCo5XbFri2oEcgOHkjrs/mCps= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ruben Vestergaard , Torkil Svensgaard , Shachar Kagan , Jeff Layton , Chuck Lever , Sasha Levin Subject: [PATCH 6.1 209/313] nfsd: dont free files unconditionally in __nfsd_file_cache_purge Date: Mon, 30 Jan 2023 14:50:44 +0100 Message-Id: <20230130134346.430994882@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134336.532886729@linuxfoundation.org> References: <20230130134336.532886729@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jeff Layton [ Upstream commit 4bdbba54e9b1c769da8ded9abd209d765715e1d6 ] 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 Tested-by: Shachar Kagan Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/filecache.c | 61 ++++++++++++++++++++++++++------------------- 1 file changed, 36 insertions(+), 25 deletions(-) diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index ea6fb0e6b165..142b3c928f76 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -638,6 +638,39 @@ static struct shrinker nfsd_file_shrinker = { .seeks = 1, }; +/** + * nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file + * @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. + */ +static void +nfsd_file_cond_queue(struct nfsd_file *nf, struct list_head *dispose) + __must_hold(RCU) +{ + 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 @@ -665,30 +698,11 @@ 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); - } + nfsd_file_cond_queue(nf, dispose); } while (1); rcu_read_unlock(); } @@ -905,11 +919,8 @@ __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) + nfsd_file_cond_queue(nf, &dispose); nf = rhashtable_walk_next(&iter); } -- 2.39.0