From patchwork Fri Feb 24 15:43:31 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 9590783 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 C92C4601AE for ; Fri, 24 Feb 2017 16:41:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 957B8287B3 for ; Fri, 24 Feb 2017 16:41:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8A0D3287BA; Fri, 24 Feb 2017 16:41:31 +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=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID 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 3F57A287B3 for ; Fri, 24 Feb 2017 16:41:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751301AbdBXQl3 (ORCPT ); Fri, 24 Feb 2017 11:41:29 -0500 Received: from merlin.infradead.org ([205.233.59.134]:58674 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751271AbdBXQlS (ORCPT ); Fri, 24 Feb 2017 11:41:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=LWQ4Tle7YM6sUPE16LUcaFIu5sFaPQGEBaOErLjwMlI=; b=sm3JRGbErE6zgRmEm84AxBhpVa eDIW9slr9L3Hj0DvTxZa78u1SrdCT8tz+PXMZuQpnqkAKjZF63PZ0byqfxIusQYPMeZJhztVPbLzE PnCpKAjC6G9UClkvHU4ifVCISC4pB/jPcHLkUEiE20Qk1awymn5YpaupH2LI3pTTVxBiv4UCdsQi6 3hDWQu435w00db5oHcs1+FTd654t3e9BWp5iW+gtyBuUTQqAD37/S0CuSSqyxG07w4GHUHe1F2Gjz nCUrj9dWIKVssVfkmJLZ0x1hHWGFEjXFQEkhSbfrAJCasWq03AbfjX8gjCxVnRz1gzAnuv+xM8RTs WPReseBg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=twins.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.87 #1 (Red Hat Linux)) id 1chItY-0004OH-Dr; Fri, 24 Feb 2017 16:39:00 +0000 Received: by twins.programming.kicks-ass.net (Postfix, from userid 0) id E24231254D6C9; Fri, 24 Feb 2017 17:39:03 +0100 (CET) Message-Id: <20170224162043.988779074@infradead.org> User-Agent: quilt/0.63-1 Date: Fri, 24 Feb 2017 16:43:31 +0100 From: Peter Zijlstra To: Al Viro , Linus Torvalds , Chris Mason Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, David Howells , elena.reshetova@intel.com, ishkamiel@gmail.com, dwindsor@gmail.com, gregkh@linuxfoundation.org, peterz@infradead.org Subject: [RFC][PATCH 02/10] fs: Avoid looking at i_count without i_lock held References: <20170224154329.478276481@infradead.org> MIME-Version: 1.0 Content-Disposition: inline; filename=peterz-fs-inode-2.patch 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 In general i_count will only stay 0 if we have i_lock held. I realize this is evict, so having MS_ACTIVE cleared might avoid the race against find_inode_fast() in other ways. Signed-off-by: Peter Zijlstra (Intel) --- fs/inode.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/inode.c +++ b/fs/inode.c @@ -604,10 +604,12 @@ void evict_inodes(struct super_block *sb again: spin_lock(&sb->s_inode_list_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { - if (atomic_read(&inode->i_count)) + spin_lock(&inode->i_lock); + if (atomic_read(&inode->i_count)) { + spin_unlock(&inode->i_lock); continue; + } - spin_lock(&inode->i_lock); if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { spin_unlock(&inode->i_lock); continue;