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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 A18A8C2D0EF for ; Thu, 16 Apr 2020 04:55:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84A1920767 for ; Thu, 16 Apr 2020 04:55:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404328AbgDPEzO (ORCPT ); Thu, 16 Apr 2020 00:55:14 -0400 Received: from mga05.intel.com ([192.55.52.43]:5444 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392050AbgDPEzN (ORCPT ); Thu, 16 Apr 2020 00:55:13 -0400 IronPort-SDR: Xe/Yh5tA/rdPb13tcbu9p8/t4nh7R4q7k0FoQOwsYA1ikqg3bOLxe9OgxLCLzQ1ViFPjoobkq9 8doApZkQwBqA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2020 21:55:12 -0700 IronPort-SDR: pZtd7vRp+1wAfFFUc4dYQhNxwL7ML1BPxtXVmt14bXI9MjzxEXGDgb6vWxttxE6aJuQpPdluMT MpBvmjg1273Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,388,1580803200"; d="scan'208";a="257087980" Received: from iweiny-desk2.sc.intel.com ([10.3.52.147]) by orsmga006.jf.intel.com with ESMTP; 15 Apr 2020 21:55:11 -0700 Date: Wed, 15 Apr 2020 21:55:11 -0700 From: Ira Weiny To: Jan Kara Cc: linux-kernel@vger.kernel.org, "Darrick J. Wong" , Dan Williams , Dave Chinner , Christoph Hellwig , "Theodore Y. Ts'o" , Jeff Moyer , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH V8 09/11] fs: Introduce DCACHE_DONTCACHE Message-ID: <20200416045511.GI2309605@iweiny-DESK2.sc.intel.com> References: <20200415064523.2244712-1-ira.weiny@intel.com> <20200415064523.2244712-10-ira.weiny@intel.com> <20200415090153.GF501@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200415090153.GF501@quack2.suse.cz> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Apr 15, 2020 at 11:01:53AM +0200, Jan Kara wrote: > On Tue 14-04-20 23:45:21, ira.weiny@intel.com wrote: > > From: Ira Weiny > > > > DCACHE_DONTCACHE indicates a dentry should not be cached on final > > dput(). > > > > Also add a helper function which will flag I_DONTCACHE as well ad > > DCACHE_DONTCACHE on all dentries point to a specified inode. > > I think this sentence needs more work :). Like: Also add a helper function > which will mark the inode with I_DONTCACHE flag and also mark all dentries > pointing to a specified inode as DCACHE_DONTCACHE. > > > > > Signed-off-by: Ira Weiny > > > > --- > > Changes from V7: > > new patch > > --- > > fs/dcache.c | 4 ++++ > > fs/inode.c | 15 +++++++++++++++ > > include/linux/dcache.h | 2 ++ > > include/linux/fs.h | 1 + > > 4 files changed, 22 insertions(+) > > ... > > > diff --git a/fs/inode.c b/fs/inode.c > > index 93d9252a00ab..b8b1917a324e 100644 > > --- a/fs/inode.c > > +++ b/fs/inode.c > > @@ -1526,6 +1526,21 @@ int generic_delete_inode(struct inode *inode) > > } > > EXPORT_SYMBOL(generic_delete_inode); > > > > +void flag_inode_dontcache(struct inode *inode) > > mark_inode_dontcache? That works. > > > +{ > > + struct dentry *dent; > > This is really nitpicking but dentry variables are usually called 'de' or > 'dentry' :) Easy change. done. > > > + > > + rcu_read_lock(); > > I don't think this list is safe to traverse under RCU. E.g. > dentry_unlink_inode() does hlist_del_init(&dentry->d_u.d_alias). Usually, > we traverse this list under inode->i_lock protection AFAICS. Ah... not sure where I got that. I thought I found this locked with rcu somewhere but I obviously got confused. And I did not even use the rcu version of the list iterator... :-( I'll clean it up, thanks for the review, Ira > > Honza > > > + hlist_for_each_entry(dent, &inode->i_dentry, d_u.d_alias) { > > + spin_lock(&dent->d_lock); > > + dent->d_flags |= DCACHE_DONTCACHE; > > + spin_unlock(&dent->d_lock); > > + } > > + rcu_read_unlock(); > > + inode->i_state |= I_DONTCACHE; > > +} > > +EXPORT_SYMBOL(flag_inode_dontcache); > > + > > /* > > * Called when we're dropping the last reference > > * to an inode. > -- > Jan Kara > SUSE Labs, CR