Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752856AbcDNXde (ORCPT ); Thu, 14 Apr 2016 19:33:34 -0400 Received: from g2t4623.austin.hp.com ([15.73.212.78]:54425 "EHLO g2t4623.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752728AbcDNXdc (ORCPT ); Thu, 14 Apr 2016 19:33:32 -0400 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 3/5] fsnotify: Simplify inode iteration on umount Date: Thu, 14 Apr 2016 19:32:30 -0400 Message-Id: <1460676752-57010-4-git-send-email-Waiman.Long@hpe.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1460676752-57010-1-git-send-email-Waiman.Long@hpe.com> References: <1460676752-57010-1-git-send-email-Waiman.Long@hpe.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2670 Lines: 91 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); } -- 1.7.1