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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B72A3C4360F for ; Wed, 3 Apr 2019 18:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 764D9205C9 for ; Wed, 3 Apr 2019 18:34:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726155AbfDCSeP (ORCPT ); Wed, 3 Apr 2019 14:34:15 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:34960 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726099AbfDCSeP (ORCPT ); Wed, 3 Apr 2019 14:34:15 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux)) id 1hBkiC-0005rO-7L; Wed, 03 Apr 2019 18:34:12 +0000 Date: Wed, 3 Apr 2019 19:34:12 +0100 From: Al Viro 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, linux-api@vger.kernel.org, linux-crypto@vger.kernel.org, keyrings@vger.kernel.org, Paul Crowley , Satya Tangirala Subject: Re: [PATCH v4 07/17] fs/dcache.c: add shrink_dcache_inode() Message-ID: <20190403183411.GV2217@ZenIV.linux.org.uk> References: <20190402154600.32432-1-ebiggers@kernel.org> <20190402154600.32432-8-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190402154600.32432-8-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Tue, Apr 02, 2019 at 08:45:50AM -0700, Eric Biggers wrote: > From: Eric Biggers > > When a filesystem encryption key is removed, we need all files which had > been "unlocked" (had ->i_crypt_info set up) with it to appear "locked" > again. This is most easily done by evicting the inodes. This can > currently be done using 'echo 2 > /proc/sys/vm/drop_caches'; however, > that is overkill and not usable by non-root users. > > To evict just the needed inodes we also need the ability to evict those > inodes' dentries, since an inode is pinned by its dentries. Therefore, > add a function shrink_dcache_inode() which iterates through an inode's > dentries and evicts any unused ones as well as any unused descendants > (since there may be negative dentries pinning the inode's dentries). Huh? > + * Evict all unused aliases of the specified inode from the dcache. This is > + * intended to be used when trying to evict a specific inode, since inodes are > + * pinned by their dentries. We also have to descend to ->d_subdirs for each > + * alias, since aliases may be pinned by negative child dentries. > + */ > +void shrink_dcache_inode(struct inode *inode) > +{ > + for (;;) { > + struct select_data data; > + struct dentry *dentry; > + > + INIT_LIST_HEAD(&data.dispose); > + data.start = NULL; > + data.found = 0; > + > + spin_lock(&inode->i_lock); > + hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) > + d_walk(dentry, &data, select_collect); > + spin_unlock(&inode->i_lock); > + > + if (!data.found) > + break; > + > + shrink_dentry_list(&data.dispose); > + cond_resched(); This is... odd. What's wrong with if (S_ISDIR(inode->i_mode)) { dentry = d_find_any_alias(inode); if (dentry) { shrink_dcache_parent(dentry); dput(dentry); } } d_prune_aliases(inode); instead of that thing?