Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752774AbZLIPmJ (ORCPT ); Wed, 9 Dec 2009 10:42:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750989AbZLIPmI (ORCPT ); Wed, 9 Dec 2009 10:42:08 -0500 Received: from mail-yx0-f187.google.com ([209.85.210.187]:57149 "EHLO mail-yx0-f187.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751015AbZLIPmH convert rfc822-to-8bit (ORCPT ); Wed, 9 Dec 2009 10:42:07 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=YBnXpU10MxHYcdqt/+98HbARqVQK603JWn4drStAV5EiXHe+OyTl5flI+UX65YvvXP pq3OT1yqGZAYyOn/K2CNUFhSVIZ+K14QFEld/25k3RjME0lhH1XnXgFK5pFO/g0Itt6j 0g907G8KHTjlfIfNVeyOfQBxvhBxHWUeIK8pE= MIME-Version: 1.0 In-Reply-To: <1259781409-31318-1-git-send-email-jack@suse.cz> References: <1259781409-31318-1-git-send-email-jack@suse.cz> Date: Wed, 9 Dec 2009 17:42:12 +0200 Message-ID: Subject: Re: [PATCH 1/3] ext3: Fix data / filesystem corruption when write fails to copy data From: saeed bishara To: Jan Kara Cc: LKML , Andrew Morton , linux-ext4@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3877 Lines: 96 Hi, I came a cross data corruption bug when using ext3, this patch fixed it. the bug exists in 2.6.31 and 32. saeed On Wed, Dec 2, 2009 at 9:16 PM, Jan Kara wrote: > When ext3_write_begin fails after allocating some blocks or > generic_perform_write fails to copy data to write, we truncate blocks already > instantiated beyond i_size. Although these blocks were never inside i_size, we > have to truncate pagecache of these blocks so that corresponding buffers get > unmapped. Otherwise subsequent __block_prepare_write (called because we are > retrying the write) will find the buffers mapped, not call ->get_block, and > thus the page will be backed by already freed blocks leading to filesystem and > data corruption. > > CC: linux-ext4@vger.kernel.org > Reported-by: James Y Knight > Signed-off-by: Jan Kara > --- >  fs/ext3/inode.c |   18 ++++++++++++++---- >  1 files changed, 14 insertions(+), 4 deletions(-) > > I will take care of merging this patch. I'm just sending it for completeness... > > diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c > index 354ed3b..f9d6937 100644 > --- a/fs/ext3/inode.c > +++ b/fs/ext3/inode.c > @@ -1151,6 +1151,16 @@ static int do_journal_get_write_access(handle_t *handle, >        return ext3_journal_get_write_access(handle, bh); >  } > > +/* > + * Truncate blocks that were not used by write. We have to truncate the > + * pagecache as well so that corresponding buffers get properly unmapped. > + */ > +static void ext3_truncate_failed_write(struct inode *inode) > +{ > +       truncate_inode_pages(inode->i_mapping, inode->i_size); > +       ext3_truncate(inode); > +} > + >  static int ext3_write_begin(struct file *file, struct address_space *mapping, >                                loff_t pos, unsigned len, unsigned flags, >                                struct page **pagep, void **fsdata) > @@ -1209,7 +1219,7 @@ write_begin_failed: >                unlock_page(page); >                page_cache_release(page); >                if (pos + len > inode->i_size) > -                       ext3_truncate(inode); > +                       ext3_truncate_failed_write(inode); >        } >        if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries)) >                goto retry; > @@ -1304,7 +1314,7 @@ static int ext3_ordered_write_end(struct file *file, >        page_cache_release(page); > >        if (pos + len > inode->i_size) > -               ext3_truncate(inode); > +               ext3_truncate_failed_write(inode); >        return ret ? ret : copied; >  } > > @@ -1330,7 +1340,7 @@ static int ext3_writeback_write_end(struct file *file, >        page_cache_release(page); > >        if (pos + len > inode->i_size) > -               ext3_truncate(inode); > +               ext3_truncate_failed_write(inode); >        return ret ? ret : copied; >  } > > @@ -1383,7 +1393,7 @@ static int ext3_journalled_write_end(struct file *file, >        page_cache_release(page); > >        if (pos + len > inode->i_size) > -               ext3_truncate(inode); > +               ext3_truncate_failed_write(inode); >        return ret ? ret : copied; >  } > > -- > 1.6.4.2 > > -- > 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/ > -- 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/