Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754336AbZCKSNt (ORCPT ); Wed, 11 Mar 2009 14:13:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753500AbZCKSNk (ORCPT ); Wed, 11 Mar 2009 14:13:40 -0400 Received: from mail.parknet.ad.jp ([210.171.162.6]:53259 "EHLO mail.officemail.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753488AbZCKSNj (ORCPT ); Wed, 11 Mar 2009 14:13:39 -0400 From: OGAWA Hirofumi To: Linus Torvalds Cc: Laurent GUERBY , linux-kernel Subject: Re: [2.6.29-rc5][BUG] swapon on vfat file gets stuck on inode lock References: <1236779832.11347.2082.camel@localhost> <87ocw80z6s.fsf@devron.myhome.or.jp> Date: Thu, 12 Mar 2009 03:13:34 +0900 In-Reply-To: <87ocw80z6s.fsf@devron.myhome.or.jp> (OGAWA Hirofumi's message of "Thu, 12 Mar 2009 02:03:23 +0900") Message-ID: <874oy0orld.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.91 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Anti-Virus: Kaspersky Anti-Virus for MailServers 5.5.10/RELEASE, bases: 24052007 #308098, status: clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1836 Lines: 52 OGAWA Hirofumi writes: > I'm sure that path touch the metadata without locking (so, reused entry > can not be for that inode anymore). However, I guess the result doesn't > become any fs corruption, so and other fs is ignoring the possibly wrong > result of bmap(). > > I'm thinking to use this patch instead of removing. Ok. Simple stress test was done. BTW, since fat caches the metadata on that path, fat would be sensitive to race more than other fs. Anyway, if you are ok, please apply. Otherwise, I'm going to prepare for this patch to next merge window. Thanks. > [PATCH] Fix _fat_bmap() locking > > On swapon() path, it has already i_mutex. So, this uses i_alloc_sem > instead of it. > > Signed-off-by: OGAWA Hirofumi > --- > > fs/fat/inode.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff -puN fs/fat/inode.c~fat_bmap-locking-fix fs/fat/inode.c > --- linux-2.6/fs/fat/inode.c~fat_bmap-locking-fix 2009-03-12 00:47:15.000000000 +0900 > +++ linux-2.6-hirofumi/fs/fat/inode.c 2009-03-12 00:47:42.000000000 +0900 > @@ -202,9 +202,9 @@ static sector_t _fat_bmap(struct address > sector_t blocknr; > > /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ > - mutex_lock(&mapping->host->i_mutex); > + down_read(&mapping->host->i_alloc_sem); > blocknr = generic_block_bmap(mapping, block, fat_get_block); > - mutex_unlock(&mapping->host->i_mutex); > + up_read(&mapping->host->i_alloc_sem); > > return blocknr; > } > _ -- OGAWA Hirofumi -- 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/