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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5281C2BA83 for ; Thu, 13 Feb 2020 15:23:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9F782469C for ; Thu, 13 Feb 2020 15:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581607427; bh=c37catCXQ/yGhz6D+YLiRTmWKuW5Gr2suXO/MLMWmkM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Uv9THyvtr0mxOBFepn7FThtX+C6nLF6k4/BaY8k5r3k2UZZ3g5WhBRN3sbSWOdf0Q nLYVQNrhR6LWPgxoWBUIsa5ztGjzWPIVlrfzwofPKPEBYj10gXtqU+UwxdKcJb4+bt uuQmPUIRwLfHx0w7IRxAiTGf54xkNF7I/sEccWBo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728475AbgBMPXr (ORCPT ); Thu, 13 Feb 2020 10:23:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:33146 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728222AbgBMPXC (ORCPT ); Thu, 13 Feb 2020 10:23:02 -0500 Received: from localhost (unknown [104.132.1.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E60902469A; Thu, 13 Feb 2020 15:23:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581607382; bh=c37catCXQ/yGhz6D+YLiRTmWKuW5Gr2suXO/MLMWmkM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1CcbJCivwBZw7flxuI4TL164MftH8vN7LosbyHDpuUfSggO1z7GHRij5BnfJC6KGM jq6LK67G9KM4iFSWGyDj4TXa2Iid9qtIm0O7qDiwkg6wyqpG7+HYd+/DjjQ6cZRZHp xgByFttSOeDWQm2kKhcqtXoIRR7WGn3Xr0IgiEa8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Benjamin Coddington , Anna Schumaker , Sasha Levin Subject: [PATCH 4.4 62/91] NFS: Directory page cache pages need to be locked when read Date: Thu, 13 Feb 2020 07:20:19 -0800 Message-Id: <20200213151846.058632156@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200213151821.384445454@linuxfoundation.org> References: <20200213151821.384445454@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Trond Myklebust [ Upstream commit 114de38225d9b300f027e2aec9afbb6e0def154b ] When a NFS directory page cache page is removed from the page cache, its contents are freed through a call to nfs_readdir_clear_array(). To prevent the removal of the page cache entry until after we've finished reading it, we must take the page lock. Fixes: 11de3b11e08c ("NFS: Fix a memory leak in nfs_readdir") Cc: stable@vger.kernel.org # v2.6.37+ Signed-off-by: Trond Myklebust Reviewed-by: Benjamin Coddington Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- fs/nfs/dir.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index e2927aeb092d0..2ac3d2527ad20 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -720,8 +720,6 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page) static void cache_page_release(nfs_readdir_descriptor_t *desc) { - if (!desc->page->mapping) - nfs_readdir_clear_array(desc->page); page_cache_release(desc->page); desc->page = NULL; } @@ -735,19 +733,28 @@ struct page *get_cache_page(nfs_readdir_descriptor_t *desc) /* * Returns 0 if desc->dir_cookie was found on page desc->page_index + * and locks the page to prevent removal from the page cache. */ static -int find_cache_page(nfs_readdir_descriptor_t *desc) +int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc) { int res; desc->page = get_cache_page(desc); if (IS_ERR(desc->page)) return PTR_ERR(desc->page); - - res = nfs_readdir_search_array(desc); + res = lock_page_killable(desc->page); if (res != 0) - cache_page_release(desc); + goto error; + res = -EAGAIN; + if (desc->page->mapping != NULL) { + res = nfs_readdir_search_array(desc); + if (res == 0) + return 0; + } + unlock_page(desc->page); +error: + cache_page_release(desc); return res; } @@ -762,7 +769,7 @@ int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) desc->last_cookie = 0; } do { - res = find_cache_page(desc); + res = find_and_lock_cache_page(desc); } while (res == -EAGAIN); return res; } @@ -807,7 +814,6 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc) nfs_readdir_release_array(desc->page); out: - cache_page_release(desc); dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (unsigned long long)*desc->dir_cookie, res); return res; @@ -853,13 +859,13 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc) status = nfs_do_filldir(desc); + out_release: + nfs_readdir_clear_array(desc->page); + cache_page_release(desc); out: dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); return status; - out_release: - cache_page_release(desc); - goto out; } /* The file offset position represents the dirent entry number. A @@ -925,6 +931,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) break; res = nfs_do_filldir(desc); + unlock_page(desc->page); + cache_page_release(desc); if (res < 0) break; } while (!desc->eof); -- 2.20.1