From: Theodore Ts'o Subject: Re: [PATCH] ext4: use percpu counter for extent cache count Date: Sat, 2 Mar 2013 10:26:44 -0500 Message-ID: <20130302152644.GA22941@thunk.org> References: <20130227185625.GA224@x4> <20130227191923.GA1121@redhat.com> <20130227192907.GB14253@thunk.org> <20130227201217.GD14253@thunk.org> <20130301033005.GA7081@redhat.com> <20130301040039.GA4452@thunk.org> <20130301050029.GB4452@thunk.org> <5130DA71.4040808@redhat.com> <20130301180035.GB17920@thunk.org> <5130ED3A.30003@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Jones , "gnehzuil.liu" , Zheng Liu , "linux-ext4@vger.kernel.org" To: Eric Sandeen Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:50928 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835Ab3CBP0v (ORCPT ); Sat, 2 Mar 2013 10:26:51 -0500 Content-Disposition: inline In-Reply-To: <5130ED3A.30003@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Mar 01, 2013 at 12:02:34PM -0600, Eric Sandeen wrote: > > I was mostly keying off what quota felt was best, I guess. > I'm not wedded to either approach, it was just a thought. > So you can take it or leave it. :) I'll take it, but for the record, there's a reason why I label patches with "I haven't tested this yet" disclaimers. For future reference, calling percpu_counter_init() and percpu_counter_destroy() is not optional --- without them, in your original patch, the kernel will crash them the first time an ext4 file system mount is attempted. No worries though, no harm done --- but it's better if people don't rely on me to catch bugs before they go into the tree. :-) - Ted diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 373d46c..1ae5860 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -783,6 +783,7 @@ static void ext4_put_super(struct super_block *sb) percpu_counter_destroy(&sbi->s_freeinodes_counter); percpu_counter_destroy(&sbi->s_dirs_counter); percpu_counter_destroy(&sbi->s_dirtyclusters_counter); + percpu_counter_destroy(&sbi->s_extent_cache_cnt); brelse(sbi->s_sbh); #ifdef CONFIG_QUOTA for (i = 0; i < MAXQUOTAS; i++) @@ -3688,6 +3689,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) if (!err) { err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0); } + if (!err) { + err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0); + } if (err) { ext4_msg(sb, KERN_ERR, "insufficient memory"); goto failed_mount3; @@ -3993,6 +3997,7 @@ failed_mount3: percpu_counter_destroy(&sbi->s_freeinodes_counter); percpu_counter_destroy(&sbi->s_dirs_counter); percpu_counter_destroy(&sbi->s_dirtyclusters_counter); + percpu_counter_destroy(&sbi->s_extent_cache_cnt); if (sbi->s_mmp_tsk) kthread_stop(sbi->s_mmp_tsk); failed_mount2: