From patchwork Fri Jul 15 17:39:41 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 9232357 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1F05B60868 for ; Fri, 15 Jul 2016 17:40:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F318C27B16 for ; Fri, 15 Jul 2016 17:40:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E7A4E27C39; Fri, 15 Jul 2016 17:40:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8CC6927B16 for ; Fri, 15 Jul 2016 17:40:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751990AbcGORkD (ORCPT ); Fri, 15 Jul 2016 13:40:03 -0400 Received: from g2t1383g.austin.hpe.com ([15.233.16.89]:30553 "EHLO g2t1383g.austin.hpe.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751656AbcGORj7 (ORCPT ); Fri, 15 Jul 2016 13:39:59 -0400 Received: from g4t3425.houston.hpe.com (g4t3425.houston.hpe.com [15.241.140.78]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by g2t1383g.austin.hpe.com (Postfix) with ESMTPS id 20690FD5 for ; Fri, 15 Jul 2016 17:39:59 +0000 (UTC) Received: from g9t2301.houston.hpecorp.net (g9t2301.houston.hpecorp.net [16.220.97.129]) by g4t3425.houston.hpe.com (Postfix) with ESMTP id 3FFFA50; Fri, 15 Jul 2016 17:39:56 +0000 (UTC) Received: from RHEL65.localdomain (unknown [16.214.216.216]) by g9t2301.houston.hpecorp.net (Postfix) with ESMTP id AEF854C; Fri, 15 Jul 2016 17:39:54 +0000 (UTC) From: Waiman Long To: Alexander Viro , Jan Kara , Jeff Layton , "J. Bruce Fields" , Tejun Heo , Christoph Lameter Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Andi Kleen , Dave Chinner , Boqun Feng , Scott J Norton , Douglas Hatch , Jan Kara , Waiman Long Subject: [PATCH v3 2/4] fsnotify: Simplify inode iteration on umount Date: Fri, 15 Jul 2016 13:39:41 -0400 Message-Id: <1468604383-40362-3-git-send-email-Waiman.Long@hpe.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1468604383-40362-1-git-send-email-Waiman.Long@hpe.com> References: <1468604383-40362-1-git-send-email-Waiman.Long@hpe.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jan Kara fsnotify_unmount_inodes() played complex tricks to pin next inode in the sb->s_inodes list when iterating over all inodes. If we switch to keeping current inode pinned somewhat longer, we can make the code much simpler and standard. Signed-off-by: Jan Kara Signed-off-by: Waiman Long --- fs/notify/inode_mark.c | 45 +++++++++------------------------------------ 1 files changed, 9 insertions(+), 36 deletions(-) diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 741077d..a364524 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -150,12 +150,10 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, */ void fsnotify_unmount_inodes(struct super_block *sb) { - struct inode *inode, *next_i, *need_iput = NULL; + struct inode *inode, *iput_inode = NULL; spin_lock(&sb->s_inode_list_lock); - list_for_each_entry_safe(inode, next_i, &sb->s_inodes, i_sb_list) { - struct inode *need_iput_tmp; - + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { /* * We cannot __iget() an inode in state I_FREEING, * I_WILL_FREE, or I_NEW which is fine because by that point @@ -178,49 +176,24 @@ void fsnotify_unmount_inodes(struct super_block *sb) continue; } - need_iput_tmp = need_iput; - need_iput = NULL; - - /* In case fsnotify_inode_delete() drops a reference. */ - if (inode != need_iput_tmp) - __iget(inode); - else - need_iput_tmp = NULL; + __iget(inode); spin_unlock(&inode->i_lock); - - /* In case the dropping of a reference would nuke next_i. */ - while (&next_i->i_sb_list != &sb->s_inodes) { - spin_lock(&next_i->i_lock); - if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) && - atomic_read(&next_i->i_count)) { - __iget(next_i); - need_iput = next_i; - spin_unlock(&next_i->i_lock); - break; - } - spin_unlock(&next_i->i_lock); - next_i = list_next_entry(next_i, i_sb_list); - } - - /* - * We can safely drop s_inode_list_lock here because either - * we actually hold references on both inode and next_i or - * end of list. Also no new inodes will be added since the - * umount has begun. - */ spin_unlock(&sb->s_inode_list_lock); - if (need_iput_tmp) - iput(need_iput_tmp); + if (iput_inode) + iput(iput_inode); /* for each watch, send FS_UNMOUNT and then remove it */ fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); fsnotify_inode_delete(inode); - iput(inode); + iput_inode = inode; spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); + + if (iput_inode) + iput(iput_inode); }