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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 39885C48BDF for ; Tue, 15 Jun 2021 16:44:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 139246191A for ; Tue, 15 Jun 2021 16:44:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229493AbhFOQqa (ORCPT ); Tue, 15 Jun 2021 12:46:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229528AbhFOQq2 (ORCPT ); Tue, 15 Jun 2021 12:46:28 -0400 Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45A21C061574; Tue, 15 Jun 2021 09:44:23 -0700 (PDT) Received: by mail-qk1-x72c.google.com with SMTP id c5so5463547qka.4; Tue, 15 Jun 2021 09:44:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=y2R5nivCzpISn1Pts0wo4OZf5lGwIGE9nnTlbS7Biqw=; b=fKdDh0a8DQG4/NJxLk9kKndAbGAXAgRHHj0yH/texVnfmH2oj6ZY1YkqSULhubarC1 ii9LZmOmJX5dm6Fk1wzpXKUfHaQaAt1kYSvfPrggjggRt/b/rr6OnNNjD+5LXLmCrq4l 2vj3lFs4jwt+Vvs+oH7zEUsLl/GRYEOFM9oa8wK2xngcJVujK2R6wEJj99PvQxVxrXMM YnfFi7RIN2TFLIFudr1WHM84wgjvzZfRB/re4OMQPw5HJrTmQCPqeqAxjRGgx+KWyNti eFqd+kxmvsKDfHWLayhOaqpbt/i40h1d6xxYYk7GouMA6fZsDhBuML5zMlHIs7+4qiVJ mEnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=y2R5nivCzpISn1Pts0wo4OZf5lGwIGE9nnTlbS7Biqw=; b=fW09Jj5yq22X75Dvk+8fxbHZzY7KfgWla+w5AGU/Wg6D9Y4vUMZk2OgjXm/EALpD8f Hfu5OvU/3DVSK/akmBVsQiTCm4Kz1fVgKQtPGTwQxdU+nA/mzilB2IwCOUIxpaGKY0ws o+jRVXBY1kYGfh9ux296HF6NOhJtd4zLmTujBG0ZpzvO2UZaXXQiDbGjFzPKI/A5pEjA mM6/4hd1yI77Y7TG+s56OHuCZhLpI6XFktdSEfoho166l8MzOQtpIdao4xtGOy+7KbNH VRck5IvyZH0jJRQVXv5PSoLw+/qNq9GVDOwxr75KyVmTp276c0lxwoRVk++9zjmhgdQh /lEQ== X-Gm-Message-State: AOAM533uKqfYo0S37egO9ThreWRrcf/wmgRg7lY6nB9FKdmh5KsQPoqU 66oSVzvxjdh7MkaQ+62nokmAcCQbApJtVg== X-Google-Smtp-Source: ABdhPJx0SgEC5s3jQaBVO2he4SBEY+lb8UnyhLl/cxqxHjPE5ms6d9BM+SlETXWWMhXdbIEI0KvPzQ== X-Received: by 2002:ae9:c112:: with SMTP id z18mr531126qki.41.1623775461919; Tue, 15 Jun 2021 09:44:21 -0700 (PDT) Received: from nyarly.redhat.com ([179.233.244.167]) by smtp.gmail.com with ESMTPSA id b189sm12667327qkc.91.2021.06.15.09.44.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Jun 2021 09:44:21 -0700 (PDT) From: Thiago Rafael Becker To: linux-cifs@vger.kernel.org Cc: Steve French , LKML , Thiago Rafael Becker Subject: [PATCH] cifs: retry lookup and readdir when EAGAIN is returned. Date: Tue, 15 Jun 2021 13:42:56 -0300 Message-Id: <20210615164256.173715-1-trbecker@gmail.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org According to the investigation performed by Jacob Shivers at Red Hat, cifs_lookup and cifs_readdir leak EAGAIN when the user session is deleted on the server. Fix this issue by implementing a retry with limits, as is implemented in cifs_revalidate_dentry_attr. Reproducer based on the work by Jacob Shivers: ~~~ $ cat readdir-cifs-test.sh #!/bin/bash # Install and configure powershell and sshd on the windows # server as descibed in # https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_overview # This script uses expect(1) USER=dude SERVER=192.168.0.2 RPATH=root PASS='password' function debug_funcs { for line in $@ ; do echo "func $line +p" > /sys/kernel/debug/dynamic_debug/control done } function setup { echo 1 > /proc/fs/cifs/cifsFYI debug_funcs wait_for_compound_request \ smb2_query_dir_first cifs_readdir \ compound_send_recv cifs_reconnect_tcon \ generic_ip_connect cifs_reconnect \ smb2_reconnect_server smb2_reconnect \ cifs_readv_from_socket cifs_readv_receive tcpdump -i eth0 -w cifs.pcap host 192.168.2.182 & sleep 5 dmesg -C } function test_call { if [[ $1 == 1 ]] ; then tracer="strace -tt -f -s 4096 -o trace-$(date -Iseconds).txt" fi # Change the command here to anything apropriate $tracer ls $2 > /dev/null res=$? if [[ $1 == 1 ]] ; then if [[ $res == 0 ]] ; then 1>&2 echo success else 1>&2 echo "failure ($res)" fi fi } mountpoint /mnt > /dev/null || mount -t cifs -o username=$USER,pass=$PASS //$SERVER/$RPATH /mnt test_call 0 /mnt/ /usr/bin/expect << EOF set timeout 60 spawn ssh $USER@$SERVER expect "yes/no" { send "yes\r" expect "*?assword" { send "$PASS\r" } } "*?assword" { send "$PASS\r" } expect ">" { send "powershell close-smbsession -force\r" } expect ">" { send "exit\r" } expect eof EOF sysctl -w vm.drop_caches=2 > /dev/null sysctl -w vm.drop_caches=2 > /dev/null setup test_call 1 /mnt/ ~~~ Signed-off-by: Thiago Rafael Becker --- fs/cifs/dir.c | 4 ++++ fs/cifs/smb2ops.c | 5 +++++ 2 files changed, 9 insertions(+) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 6bcd3e8f7cda..7c641f9a3dac 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -630,6 +630,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, struct inode *newInode = NULL; const char *full_path; void *page; + int retry_count = 0; xid = get_xid(); @@ -673,6 +674,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, d_inode(direntry)); +again: if (pTcon->posix_extensions) rc = smb311_posix_get_inode_info(&newInode, full_path, parent_dir_inode->i_sb, xid); else if (pTcon->unix_ext) { @@ -687,6 +689,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, /* since paths are not looked up by component - the parent directories are presumed to be good here */ renew_parental_timestamps(direntry); + } else if (rc == -EAGAIN && retry_count++ < 10) { + goto again; } else if (rc == -ENOENT) { cifs_set_time(direntry, jiffies); newInode = NULL; diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 21ef51d338e0..d241e6af8fe4 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -2325,6 +2325,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon, struct smb2_query_directory_rsp *qd_rsp = NULL; struct smb2_create_rsp *op_rsp = NULL; struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses); + int retry_count = 0; utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); if (!utf16_path) @@ -2372,10 +2373,14 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon, smb2_set_related(&rqst[1]); +again: rc = compound_send_recv(xid, tcon->ses, server, flags, 2, rqst, resp_buftype, rsp_iov); + if (rc == -EAGAIN && retry_count++ < 10) + goto again; + /* If the open failed there is nothing to do */ op_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base; if (op_rsp == NULL || op_rsp->sync_hdr.Status != STATUS_SUCCESS) { -- 2.31.1