From patchwork Mon Jan 30 16:34:52 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Wilck X-Patchwork-Id: 138611 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 5CE00B6EFE for ; Tue, 31 Jan 2012 03:46:06 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753820Ab2A3QqE (ORCPT ); Mon, 30 Jan 2012 11:46:04 -0500 Received: from dgate20.ts.fujitsu.com ([80.70.172.51]:14623 "EHLO dgate20.ts.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753861Ab2A3QqD (ORCPT ); Mon, 30 Jan 2012 11:46:03 -0500 X-Greylist: delayed 575 seconds by postgrey-1.27 at vger.kernel.org; Mon, 30 Jan 2012 11:46:02 EST DomainKey-Signature: s=s1536a; d=ts.fujitsu.com; c=nofws; q=dns; h=X-SBRSScore:X-IronPort-AV:Received:X-IronPort-AV: Received:Received:From:To:Cc:Subject:Date:Message-Id: X-Mailer; b=ofiIviihc7P5r0fz/NpYmSL1kMgND/Sj61CT1wy/JpQ9JH7zrYYqXDpT D+USfU3CU8sTwhVjplEjq4Y/mkJgtfFVBRdhBCSM6lEgiwvh9xWk369Ss JpSBPpSRmmlCEaWVNBHilu4HnVLNtABCg/EU2CE3JTQmUkRJCHa2Erea/ tXKU/TFMt4Y9euCEDhrbGzFigJInPtQwvHPIdmaojZ4IjG/fxeNmxIxFr rcHX2eJarrfL+qMeNeo7vmGEM+bkQ; DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ts.fujitsu.com; i=martin.wilck@ts.fujitsu.com; q=dns/txt; s=s1536b; t=1327941963; x=1359477963; h=from:to:cc:subject:date:message-id; bh=DaNOUW6iV/POs/2tLyboS68M+iJfJihQHU0H6YEiPz8=; b=uiaItqoa0cVG/UTn+oyFPdZVrp6/ipl/05uPRTzYXFWFyyoaKWCQllrE 1evsEgYEQgYN1stF0jDMX5cJ7M8PpMbmVjTnUp8tuo6djTqCeFOCZm1Km UGnAaP4pUQttjb8QDckUkmlYsqLYlAPVdHnerN/ZAPDS1Uo/TAHhRXrhN hUwPCrG86Xj5YdjVzCHfhwvLux2hqh4cZ2KaYVl9fHzaTqAXXH/eFv/6w Zm4AAfS0034haZimBCMUh/Rd5GOWq; X-SBRSScore: None X-IronPort-AV: E=Sophos;i="4.71,592,1320620400"; d="scan'208";a="84862100" Received: from abgdgate30u.abg.fsc.net ([172.25.138.66]) by dgate20u.abg.fsc.net with ESMTP; 30 Jan 2012 17:36:27 +0100 X-IronPort-AV: E=Sophos;i="4.71,592,1320620400"; d="scan'208";a="127720431" Received: from unknown (HELO cooper.psw.pdbps.fsc.net) ([172.25.253.64]) by abgdgate30u.abg.fsc.net with ESMTP; 30 Jan 2012 17:36:26 +0100 Received: from cooper.psw.pdbps.fsc.net (cooper.psw.pdbps.fsc.net [127.0.0.1]) by cooper.psw.pdbps.fsc.net (8.14.5/8.14.4) with ESMTP id q0UGZ58t003939; Mon, 30 Jan 2012 17:35:05 +0100 From: Martin Wilck To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, adilger.kernel@dilger.ca, fmayhar@google.com, esandeen@redhat.com, Martin Wilck Subject: [PATCH] ext4: avoid deadlock on sync-mounted ext2 FS Date: Mon, 30 Jan 2012 17:34:52 +0100 Message-Id: <1327941292-3907-1-git-send-email-martin.wilck@ts.fujitsu.com> X-Mailer: git-send-email 1.7.7.5 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Processes hang forever on a sync-mounted ext2 file system that is mounted with the ext4 module (default in Fedora 16). I can reproduce this reliably by mounting an ext2 partition with "-o sync" and opening a new file an that partition with vim. vim will hang in "D" state forever. I am attaching a small patch here that solves this issue for me. In the sync mounted case, ext4_handle_dirty_metadata() may call sync_dirty_buffer(), which can't be called with buffer lock held. My knowledge of locking in ext4 is insufficient to judge if this patch is correct, but it may serve as starting point for others. Signed-off-by: Martin.Wilck@ts.fujitsu.com --- fs/ext4/xattr.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 93a00d8..eb771ea 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -487,8 +487,10 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode, ext4_free_blocks(handle, inode, bh, 0, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); + unlock_buffer(bh); } else { le32_add_cpu(&BHDR(bh)->h_refcount, -1); + unlock_buffer(bh); error = ext4_handle_dirty_metadata(handle, inode, bh); if (IS_SYNC(inode)) ext4_handle_sync(handle); @@ -498,7 +500,6 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode, if (ce) mb_cache_entry_release(ce); } - unlock_buffer(bh); out: ext4_std_error(inode->i_sb, error); return;