Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755206Ab2E1Dnt (ORCPT ); Sun, 27 May 2012 23:43:49 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52096 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753919Ab2E1D3d (ORCPT ); Sun, 27 May 2012 23:29:33 -0400 Message-Id: <20120528031214.326681665@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 28 May 2012 04:13:25 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Kazuya Mio , Al Viro Subject: [ 083/117] wake up s_wait_unfrozen when ->freeze_fs fails In-Reply-To: <20120528031202.829379252@decadent.org.uk> X-SA-Exim-Connect-IP: 192.168.4.185 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1609 Lines: 47 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kazuya Mio commit e1616300a20c80396109c1cf013ba9a36055a3da upstream. dd slept infinitely when fsfeeze failed because of EIO. To fix this problem, if ->freeze_fs fails, freeze_super() wakes up the tasks waiting for the filesystem to become unfrozen. When s_frozen isn't SB_UNFROZEN in __generic_file_aio_write(), the function sleeps until FITHAW ioctl wakes up s_wait_unfrozen. However, if ->freeze_fs fails, s_frozen is set to SB_UNFROZEN and then freeze_super() returns an error number. In this case, FITHAW ioctl returns EINVAL because s_frozen is already SB_UNFROZEN. There is no way to wake up s_wait_unfrozen, so __generic_file_aio_write() sleeps infinitely. Signed-off-by: Kazuya Mio Signed-off-by: Al Viro Signed-off-by: Ben Hutchings --- fs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/super.c b/fs/super.c index de41e1e..6015c02 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1186,6 +1186,8 @@ int freeze_super(struct super_block *sb) printk(KERN_ERR "VFS:Filesystem freeze failed\n"); sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); deactivate_locked_super(sb); return ret; } -- 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/