Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751734AbdIEMx4 (ORCPT ); Tue, 5 Sep 2017 08:53:56 -0400 Received: from mail-wr0-f196.google.com ([209.85.128.196]:35687 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082AbdIEMxy (ORCPT ); Tue, 5 Sep 2017 08:53:54 -0400 X-Google-Smtp-Source: ADKCNb5juNZKy8wgjFiDxUO2gMidqe4QlyfCovWuaJ2qjj+dl5lJP7nbbvJcEQ1LL94w5K9nYf2Kug== Date: Tue, 5 Sep 2017 14:53:49 +0200 From: Miklos Szeredi To: linux-fsdevel@vger.kernel.org Cc: Al Viro , linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org, Miklos Szeredi Subject: Re: [PATCH 2/3] ovl: fix relatime for directories Message-ID: <20170905125349.GC29201@veci.piliscsaba.szeredi.hu> References: <1504597596-17994-1-git-send-email-mszeredi@redhat.com> <1504597596-17994-3-git-send-email-mszeredi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1504597596-17994-3-git-send-email-mszeredi@redhat.com> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2497 Lines: 84 On Tue, Sep 5, 2017 at 10:55 AM, Amir Goldstein wrote: [...] > Alternatively, update_ovl_inode_times() could use D_REAL_UPPER > and then we explicitly say that we don't care about lower mtime/ctime > modifications. Right, you convinced me that this is the right way to go. Updated patch below (and pushed to overlayfs-next). Thanks, Miklos --- From: Miklos Szeredi Subject: ovl: fix relatime for directories Need to treat non-regular overlayfs files the same as regular files when checking for an atime update. Add a d_real() flag to make it return the upper dentry for all file types. Reported-by: "zhangyi (F)" Signed-off-by: Miklos Szeredi --- fs/inode.c | 21 +++++++++++++++++---- fs/overlayfs/super.c | 3 +++ include/linux/dcache.h | 3 +++ 3 files changed, 23 insertions(+), 4 deletions(-) --- a/fs/inode.c +++ b/fs/inode.c @@ -1569,11 +1569,24 @@ EXPORT_SYMBOL(bmap); static void update_ovl_inode_times(struct dentry *dentry, struct inode *inode, bool rcu) { - if (!rcu) { - struct inode *realinode = d_real_inode(dentry); + struct dentry *upperdentry; - if (unlikely(inode != realinode) && - (!timespec_equal(&inode->i_mtime, &realinode->i_mtime) || + /* + * Nothing to do if in rcu or if non-overlayfs + */ + if (rcu || likely(!(dentry->d_flags & DCACHE_OP_REAL))) + return; + + upperdentry = d_real(dentry, NULL, 0, D_REAL_UPPER); + + /* + * If file is on lower then we can't update atime, so no worries about + * stale mtime/ctime. + */ + if (upperdentry) { + struct inode *realinode = d_inode(upperdentry); + + if ((!timespec_equal(&inode->i_mtime, &realinode->i_mtime) || !timespec_equal(&inode->i_ctime, &realinode->i_ctime))) { inode->i_mtime = realinode->i_mtime; inode->i_ctime = realinode->i_ctime; --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -75,6 +75,9 @@ static struct dentry *ovl_d_real(struct struct dentry *real; int err; + if (flags & D_REAL_UPPER) + return ovl_dentry_upper(dentry); + if (!d_is_reg(dentry)) { if (!inode || inode == d_inode(dentry)) return dentry; --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -562,6 +562,9 @@ static inline struct dentry *d_backing_d return upper; } +/* d_real() flags */ +#define D_REAL_UPPER 0x2 /* return upper dentry or NULL if non-upper */ + /** * d_real - Return the real dentry * @dentry: the dentry to query