Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751438AbbHARJs (ORCPT ); Sat, 1 Aug 2015 13:09:48 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47229 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751292AbbHARJq (ORCPT ); Sat, 1 Aug 2015 13:09:46 -0400 Date: Sat, 1 Aug 2015 18:09:36 +0100 From: Al Viro To: Linus Torvalds Cc: Dominique Martinet , Hugh Dickins , "J. Bruce Fields" , Dominique Martinet , Linux Kernel Mailing List , linux-fsdevel , David Howells Subject: Re: v4.2-rc dcache regression, probably 75a6f82a0d10 Message-ID: <20150801170936.GX17109@ZenIV.linux.org.uk> References: <20150731205036.GA3752@nautica> <20150801072603.GV17109@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1696 Lines: 39 On Sat, Aug 01, 2015 at 09:09:24AM -0700, Linus Torvalds wrote: > On Sat, Aug 1, 2015 at 12:26 AM, Al Viro wrote: > > > > Actually, the shit had hit the fan earlier. Look: in > > commit b18825a7c8e37a7cf6abb97a12a6ad71af160de7 > > Author: David Howells > > Date: Thu Sep 12 19:22:53 2013 +0100 > > > > VFS: Put a small type field into struct dentry::d_flags > > > > we have this: > > > > - if (!can_lookup(nd->inode)) { > > + if (!d_is_directory(nd->path.dentry)) { > > Ahh. That's subtle, yes. Inodes are stable in ways that dentries > aren't. And the reason why Dominique bisected it to 4bf46a272647 would > seem to be that while dentries aren't really stable, the dentry flags > generally don't change. But dentry_iput() changed to actually clear > the type when clearing the inode, so that probably added a few cases > where it went from "stable in practice" to be more easily triggered. > > Your patch looks obviously correct, with the slight worry that there > might be other cases of this. > > > there. AFAICS, other places of that sort are not a problem anymore. > > Al, do you plan a pull request? It would be good to get this into rc5 > (tomorrow) regardless of whether there might be other issues lurking > too. Will do later today. -stable branches will be interesting, though ;-/ Al, still digging through the loads of fun stuff in l-k mailbox... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/