Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030782AbWKOWtu (ORCPT ); Wed, 15 Nov 2006 17:49:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031012AbWKOWtu (ORCPT ); Wed, 15 Nov 2006 17:49:50 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:982 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S1030782AbWKOWtt (ORCPT ); Wed, 15 Nov 2006 17:49:49 -0500 Date: Wed, 15 Nov 2006 23:49:26 +0100 From: Pavel Machek To: "Rafael J. Wysocki" Cc: David Chinner , Alasdair G Kergon , Eric Sandeen , Andrew Morton , linux-kernel@vger.kernel.org, dm-devel@redhat.com, Srinivasa DS , Nigel Cunningham Subject: Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex Message-ID: <20061115224926.GA4302@elf.ucw.cz> References: <20061107183459.GG6993@agk.surrey.redhat.com> <200611152100.35054.rjw@sisk.pl> <20061115202348.GB3875@elf.ucw.cz> <200611152258.52160.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200611152258.52160.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6129 Lines: 164 Hi! > > > > There's one more thing, actually. If the on-disk data and metadata are > > > > changed _after_ the sync we do and _before_ we create the snapshot image, > > > > and the subsequent resume fails, > > > > > > Well, but this is equivalent to a power failure immediately after the sync, so > > > there _must_ be a way to recover the filesystem from that, no? > > > > Exactly. > > > > > I think I'll prepare a patch for freezing the work queues and we'll see what > > > to do next. > > > > Thanks! > > Okay, the patch follows. > > I've been running it for some time on my boxes and it doesn't seem to break > anything. However, I don't use XFS, so well ... Seems like a way to go, thanks! Pavel > Index: linux-2.6.19-rc5-mm2/include/linux/workqueue.h > =================================================================== > --- linux-2.6.19-rc5-mm2.orig/include/linux/workqueue.h 2006-09-20 05:42:06.000000000 +0200 > +++ linux-2.6.19-rc5-mm2/include/linux/workqueue.h 2006-11-15 21:58:40.000000000 +0100 > @@ -55,9 +55,11 @@ struct execute_work { > } while (0) > > extern struct workqueue_struct *__create_workqueue(const char *name, > - int singlethread); > -#define create_workqueue(name) __create_workqueue((name), 0) > -#define create_singlethread_workqueue(name) __create_workqueue((name), 1) > + int singlethread, > + int freezeable); > +#define create_workqueue(name) __create_workqueue((name), 0, 0) > +#define create_freezeable_workqueue(name) __create_workqueue((name), 0, 1) > +#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0) > > extern void destroy_workqueue(struct workqueue_struct *wq); > > Index: linux-2.6.19-rc5-mm2/kernel/workqueue.c > =================================================================== > --- linux-2.6.19-rc5-mm2.orig/kernel/workqueue.c 2006-11-15 21:32:13.000000000 +0100 > +++ linux-2.6.19-rc5-mm2/kernel/workqueue.c 2006-11-15 22:27:40.000000000 +0100 > @@ -31,6 +31,7 @@ > #include > #include > #include > +#include > > /* > * The per-CPU workqueue (if single thread, we always use the first > @@ -57,6 +58,8 @@ struct cpu_workqueue_struct { > struct task_struct *thread; > > int run_depth; /* Detect run_workqueue() recursion depth */ > + > + int freezeable; /* Freeze the thread during suspend */ > } ____cacheline_aligned; > > /* > @@ -251,7 +254,8 @@ static int worker_thread(void *__cwq) > struct k_sigaction sa; > sigset_t blocked; > > - current->flags |= PF_NOFREEZE; > + if (!cwq->freezeable) > + current->flags |= PF_NOFREEZE; > > set_user_nice(current, -5); > > @@ -274,6 +278,9 @@ static int worker_thread(void *__cwq) > > set_current_state(TASK_INTERRUPTIBLE); > while (!kthread_should_stop()) { > + if (cwq->freezeable) > + try_to_freeze(); > + > add_wait_queue(&cwq->more_work, &wait); > if (list_empty(&cwq->worklist)) > schedule(); > @@ -350,7 +357,7 @@ void fastcall flush_workqueue(struct wor > EXPORT_SYMBOL_GPL(flush_workqueue); > > static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, > - int cpu) > + int cpu, int freezeable) > { > struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); > struct task_struct *p; > @@ -360,6 +367,7 @@ static struct task_struct *create_workqu > cwq->thread = NULL; > cwq->insert_sequence = 0; > cwq->remove_sequence = 0; > + cwq->freezeable = freezeable; > INIT_LIST_HEAD(&cwq->worklist); > init_waitqueue_head(&cwq->more_work); > init_waitqueue_head(&cwq->work_done); > @@ -375,7 +383,7 @@ static struct task_struct *create_workqu > } > > struct workqueue_struct *__create_workqueue(const char *name, > - int singlethread) > + int singlethread, int freezeable) > { > int cpu, destroy = 0; > struct workqueue_struct *wq; > @@ -395,7 +403,7 @@ struct workqueue_struct *__create_workqu > mutex_lock(&workqueue_mutex); > if (singlethread) { > INIT_LIST_HEAD(&wq->list); > - p = create_workqueue_thread(wq, singlethread_cpu); > + p = create_workqueue_thread(wq, singlethread_cpu, freezeable); > if (!p) > destroy = 1; > else > @@ -403,7 +411,7 @@ struct workqueue_struct *__create_workqu > } else { > list_add(&wq->list, &workqueues); > for_each_online_cpu(cpu) { > - p = create_workqueue_thread(wq, cpu); > + p = create_workqueue_thread(wq, cpu, freezeable); > if (p) { > kthread_bind(p, cpu); > wake_up_process(p); > @@ -657,7 +665,7 @@ static int __devinit workqueue_cpu_callb > mutex_lock(&workqueue_mutex); > /* Create a new workqueue thread for it. */ > list_for_each_entry(wq, &workqueues, list) { > - if (!create_workqueue_thread(wq, hotcpu)) { > + if (!create_workqueue_thread(wq, hotcpu, 0)) { > printk("workqueue for %i failed\n", hotcpu); > return NOTIFY_BAD; > } > Index: linux-2.6.19-rc5-mm2/fs/xfs/linux-2.6/xfs_buf.c > =================================================================== > --- linux-2.6.19-rc5-mm2.orig/fs/xfs/linux-2.6/xfs_buf.c 2006-11-15 21:32:08.000000000 +0100 > +++ linux-2.6.19-rc5-mm2/fs/xfs/linux-2.6/xfs_buf.c 2006-11-15 22:12:43.000000000 +0100 > @@ -1826,11 +1826,11 @@ xfs_buf_init(void) > if (!xfs_buf_zone) > goto out_free_trace_buf; > > - xfslogd_workqueue = create_workqueue("xfslogd"); > + xfslogd_workqueue = create_freezeable_workqueue("xfslogd"); > if (!xfslogd_workqueue) > goto out_free_buf_zone; > > - xfsdatad_workqueue = create_workqueue("xfsdatad"); > + xfsdatad_workqueue = create_freezeable_workqueue("xfsdatad"); > if (!xfsdatad_workqueue) > goto out_destroy_xfslogd_workqueue; > -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/