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,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 BEA6BC35245 for ; Fri, 24 Jan 2020 11:41:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 955C320678 for ; Fri, 24 Jan 2020 11:41:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579866094; bh=LQB4Zhi24o8/X+v34Z1NZFwGXcTPiXecARvgH7JrTaQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uB0rYrYhuOQpIwJ+BVxJ1wXCIqd+84cCovZbtanSnNUSijo5X8tYpD17F3BL1as4X blwIfSxe9ZpzMYHkBTM06PBOohK1QodmwBeWulRKo+rSTkT6PvWFzClIfHRvKgWjTN hI6sgsIWi5vf4zV6WnzAsL3WC54qQkm3DY/akSqk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390603AbgAXLSM (ORCPT ); Fri, 24 Jan 2020 06:18:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:55182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729351AbgAXLSL (ORCPT ); Fri, 24 Jan 2020 06:18:11 -0500 Received: from localhost (ip-213-127-102-57.ip.prioritytelecom.net [213.127.102.57]) (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 6247020708; Fri, 24 Jan 2020 11:18:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579864690; bh=LQB4Zhi24o8/X+v34Z1NZFwGXcTPiXecARvgH7JrTaQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J5LuMGnZ9wb1s1y8tfZ8QRA/7NhAWq9qlhR+AyrmZZKAX+WflVRoEGv8/xyqea0fG WahHP4mHh7U580NSNiVik6AnwaMUEBkvpk6WuYY8g19h8JegktyH+x/fnsEq2PStua Rxmdxkuqbd0NVSWLCFD8QM09n10IDha3UOG2CweU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jonathan Billings , David Howells , Sasha Levin Subject: [PATCH 4.19 325/639] afs: Fix AFS file locking to allow fine grained locks Date: Fri, 24 Jan 2020 10:28:15 +0100 Message-Id: <20200124093127.839498079@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124093047.008739095@linuxfoundation.org> References: <20200124093047.008739095@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Howells [ Upstream commit 68ce801ffd82e72d5005ab5458e8b9e59f24d9cc ] Fix AFS file locking to allow fine grained locks as some applications, such as firefox, won't work if they can't take such locks on certain state files - thereby preventing the use of kAFS to distribute a home directory. Note that this cannot be made completely functional as the protocol only has provision for whole-file locks, so there exists the possibility of a process deadlocking itself by getting a partial read-lock on a file first and then trying to get a non-overlapping write-lock - but we got the server's read lock with the first lock, so we're now stuck. OpenAFS solves this by just granting any partial-range lock directly without consulting the server - and hoping there's no remote collision. I want to implement that in a separate patch and it requires a bit more thought. Fixes: 8d6c554126b8 ("AFS: implement file locking") Reported-by: Jonathan Billings Signed-off-by: David Howells Signed-off-by: Sasha Levin --- fs/afs/flock.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/fs/afs/flock.c b/fs/afs/flock.c index 1bb300ef362b0..dffbb456629c9 100644 --- a/fs/afs/flock.c +++ b/fs/afs/flock.c @@ -432,10 +432,6 @@ static int afs_do_setlk(struct file *file, struct file_lock *fl) _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); - /* only whole-file locks are supported */ - if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) - return -EINVAL; - fl->fl_ops = &afs_lock_ops; INIT_LIST_HEAD(&fl->fl_u.afs.link); fl->fl_u.afs.state = AFS_LOCK_PENDING; @@ -587,10 +583,6 @@ static int afs_do_unlk(struct file *file, struct file_lock *fl) /* Flush all pending writes before doing anything with locks. */ vfs_fsync(file, 0); - /* only whole-file unlocks are supported */ - if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) - return -EINVAL; - ret = posix_lock_file(file, fl, NULL); _leave(" = %d [%u]", ret, vnode->lock_state); return ret; @@ -618,12 +610,15 @@ static int afs_do_getlk(struct file *file, struct file_lock *fl) goto error; lock_count = READ_ONCE(vnode->status.lock_count); - if (lock_count > 0) - fl->fl_type = F_RDLCK; - else - fl->fl_type = F_WRLCK; - fl->fl_start = 0; - fl->fl_end = OFFSET_MAX; + if (lock_count != 0) { + if (lock_count > 0) + fl->fl_type = F_RDLCK; + else + fl->fl_type = F_WRLCK; + fl->fl_start = 0; + fl->fl_end = OFFSET_MAX; + fl->fl_pid = 0; + } } ret = 0; -- 2.20.1