From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: dcache shrink list corruption? Date: Sat, 3 May 2014 19:21:11 +0100 Message-ID: <20140503182110.GN18016@ZenIV.linux.org.uk> References: <20140429232013.GM18016@ZenIV.linux.org.uk> <20140430023142.GN18016@ZenIV.linux.org.uk> <20140430091515.GB3113@tucsk.piliscsaba.szeredi.hu> <20140502055127.GH18016@ZenIV.linux.org.uk> <20140502210813.GB32527@tucsk.piliscsaba.szeredi.hu> <20140502224022.GJ18016@ZenIV.linux.org.uk> <20140503042604.GM18016@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Miklos Szeredi , Dave Chinner , Linux Kernel Mailing List , linux-fsdevel To: Linus Torvalds Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:36757 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752193AbaECSVN (ORCPT ); Sat, 3 May 2014 14:21:13 -0400 Content-Disposition: inline In-Reply-To: <20140503042604.GM18016@ZenIV.linux.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Sat, May 03, 2014 at 05:26:04AM +0100, Al Viro wrote: > See vfs.git#dentry_kill-3; warning - this is completely untested and I would > really like comments on spinning case there (i.e. the one where select_collect() > finds some stuff already on some other shrink list and nothing with zero > refcount that wouldn't be there). In that case (and it's basically "somebody > else is evicting stuff in our subtree and they'd already picked everything > we want evicted") I just let the loop in check_submounts_and_drop() repeat > (we do have cond_resched() there). Any better suggestions would be welcome... Hmm... As the matter of fact, the whole shrink_dcache_for_umount() could be made a lot saner. What we need is to reuse shrink_dcache_parent() and follow it with d_walk() that would just go through whatever remains and complain about the leaves of that. For anon roots we'll obviously need to wrap that into dget and d_drop/dput. I'm testing that right now; everything seems to be working so far and if it survives, I'll push that sucker out. Total since the beginning of the whole series: fs/dcache.c | 310 ++++++++++++++++++++++++++++++++--------------------------------------------------------- include/linux/dcache.h | 2 + 2 files changed, 112 insertions(+), 200 deletions(-) Anyway, I'm off to finish with acct.c races, then it's time for Eric's lazy umount on unlink series; this work is getting unpleasantly close to the areas he's touching, so I'd better get it on top of this stuff and into -next...