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=unavailable 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 2F91CC2BA19 for ; Tue, 14 Apr 2020 15:26:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C59620656 for ; Tue, 14 Apr 2020 15:26:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439728AbgDNP0p (ORCPT ); Tue, 14 Apr 2020 11:26:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:52362 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729755AbgDNP0d (ORCPT ); Tue, 14 Apr 2020 11:26:33 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 61AF7AB8F; Tue, 14 Apr 2020 15:26:30 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 2631D1E125F; Tue, 14 Apr 2020 17:26:30 +0200 (CEST) Date: Tue, 14 Apr 2020 17:26:30 +0200 From: Jan Kara To: ira.weiny@intel.com Cc: linux-kernel@vger.kernel.org, "Darrick J. Wong" , Dan Williams , Dave Chinner , Christoph Hellwig , "Theodore Y. Ts'o" , Jan Kara , Jeff Moyer , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH V7 7/9] fs: Define I_DONTCACNE in VFS layer Message-ID: <20200414152630.GE28226@quack2.suse.cz> References: <20200413054046.1560106-1-ira.weiny@intel.com> <20200413054046.1560106-8-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200413054046.1560106-8-ira.weiny@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 12-04-20 22:40:44, ira.weiny@intel.com wrote: > From: Ira Weiny > > DAX effective mode changes (setting of S_DAX) require inode eviction. > > Define a flag which can be set to inform the VFS layer that inodes > should not be cached. This will expedite the eviction of those nodes > requiring reload. > > Signed-off-by: Ira Weiny This inode flag will have a limited impact because usually dentry will still hold inode reference. So until dentry is evicted, inode stays as well. So I think we'd need something like DCACHE_DONTCACHE flag as well to discard a dentry whenever dentry usecount hits zero (which will be generally on last file close). What do you think? And I'd note that checking for I_DONTCACHE flag in dput() isn't straightforward because of locking so that's why I suggest separate dentry flag. Honza > --- > include/linux/fs.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index a818ced22961..e2db71d150c3 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2151,6 +2151,8 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src, > * > * I_CREATING New object's inode in the middle of setting up. > * > + * I_DONTCACHE Do not cache the inode > + * > * Q: What is the difference between I_WILL_FREE and I_FREEING? > */ > #define I_DIRTY_SYNC (1 << 0) > @@ -2173,6 +2175,7 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src, > #define I_WB_SWITCH (1 << 13) > #define I_OVL_INUSE (1 << 14) > #define I_CREATING (1 << 15) > +#define I_DONTCACHE (1 << 16) > > #define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC) > #define I_DIRTY (I_DIRTY_INODE | I_DIRTY_PAGES) > @@ -3042,7 +3045,8 @@ extern int inode_needs_sync(struct inode *inode); > extern int generic_delete_inode(struct inode *inode); > static inline int generic_drop_inode(struct inode *inode) > { > - return !inode->i_nlink || inode_unhashed(inode); > + return !inode->i_nlink || inode_unhashed(inode) || > + (inode->i_state & I_DONTCACHE); > } > > extern struct inode *ilookup5_nowait(struct super_block *sb, > -- > 2.25.1 > -- Jan Kara SUSE Labs, CR