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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 C2090C282DA for ; Wed, 17 Apr 2019 16:56:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 992372173C for ; Wed, 17 Apr 2019 16:56:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732738AbfDQQ4b (ORCPT ); Wed, 17 Apr 2019 12:56:31 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:50587 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731454AbfDQQ4b (ORCPT ); Wed, 17 Apr 2019 12:56:31 -0400 Received: from callcc.thunk.org (guestnat-104-133-0-109.corp.google.com [104.133.0.109] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x3HGtvvX009766 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Apr 2019 12:55:57 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id DA50D420497; Wed, 17 Apr 2019 12:55:56 -0400 (EDT) Date: Wed, 17 Apr 2019 12:55:56 -0400 From: "Theodore Ts'o" To: Eric Biggers Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, Al Viro Subject: Re: [PATCH v2 2/2] fscrypt: cache decrypted symlink target in ->i_link Message-ID: <20190417165556.GI4686@mit.edu> References: <20190410202115.64501-1-ebiggers@kernel.org> <20190410202115.64501-3-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190410202115.64501-3-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Apr 10, 2019 at 01:21:15PM -0700, Eric Biggers wrote: > From: Eric Biggers > > Path lookups that traverse encrypted symlink(s) are very slow because > each encrypted symlink needs to be decrypted each time it's followed. > This also involves dropping out of rcu-walk mode. > > Make encrypted symlinks faster by caching the decrypted symlink target > in ->i_link. The first call to fscrypt_get_symlink() sets it. Then, > the existing VFS path lookup code uses the non-NULL ->i_link to take the > fast path where ->get_link() isn't called, and lookups in rcu-walk mode > remain in rcu-walk mode. > > Also set ->i_link immediately when a new encrypted symlink is created. > > To safely free the symlink target after an RCU grace period has elapsed, > introduce a new function fscrypt_free_inode(), and make the relevant > filesystems call it just before actually freeing the inode. > > Cc: Al Viro > Signed-off-by: Eric Biggers Looks good, applied. - Ted