From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F90DC4707A for ; Sun, 23 May 2021 11:53:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A0DD61166 for ; Sun, 23 May 2021 11:53:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231752AbhEWLy1 (ORCPT ); Sun, 23 May 2021 07:54:27 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:32825 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231741AbhEWLy1 (ORCPT ); Sun, 23 May 2021 07:54:27 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=joseph.qi@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UZnHIaz_1621770777; Received: from B-D1K7ML85-0059.local(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0UZnHIaz_1621770777) by smtp.aliyun-inc.com(127.0.0.1); Sun, 23 May 2021 19:52:58 +0800 Subject: Re: [PATCH v2] ocfs2: fix data corruption by fallocate To: Junxiao Bi , ocfs2-devel@oss.oracle.com Cc: jack@suse.cz, linux-fsdevel@vger.kernel.org References: <20210521233612.75185-1-junxiao.bi@oracle.com> From: Joseph Qi Message-ID: <35a1d32b-b8d7-ea9b-d28c-6b4fd837605d@linux.alibaba.com> Date: Sun, 23 May 2021 19:52:57 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210521233612.75185-1-junxiao.bi@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi Junxiao, If change_size is true (!FALLOC_FL_KEEP_SIZE), it will update isize in __ocfs2_change_file_space(). Why do we have to zeroout first? Thanks, Joseph On 5/22/21 7:36 AM, Junxiao Bi wrote: > When fallocate punches holes out of inode size, if original isize is in > the middle of last cluster, then the part from isize to the end of the > cluster will be zeroed with buffer write, at that time isize is not > yet updated to match the new size, if writeback is kicked in, it will > invoke ocfs2_writepage()->block_write_full_page() where the pages out > of inode size will be dropped. That will cause file corruption. Fix > this by zero out eof blocks when extending the inode size. > > Running the following command with qemu-image 4.2.1 can get a corrupted > coverted image file easily. > > qemu-img convert -p -t none -T none -f qcow2 $qcow_image \ > -O qcow2 -o compat=1.1 $qcow_image.conv > > The usage of fallocate in qemu is like this, it first punches holes out of > inode size, then extend the inode size. > > fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 65536) = 0 > fallocate(11, 0, 2276196352, 65536) = 0 > > v1: https://www.spinics.net/lists/linux-fsdevel/msg193999.html > > Cc: > Cc: Jan Kara > Signed-off-by: Junxiao Bi > --- > > Changes in v2: > - suggested by Jan Kara, using sb_issue_zeroout to zero eof blocks in disk directly. > > fs/ocfs2/file.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 47 insertions(+), 2 deletions(-) > > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c > index f17c3d33fb18..17469fc7b20e 100644 > --- a/fs/ocfs2/file.c > +++ b/fs/ocfs2/file.c > @@ -1855,6 +1855,45 @@ int ocfs2_remove_inode_range(struct inode *inode, > return ret; > } > > +/* > + * zero out partial blocks of one cluster. > + * > + * start: file offset where zero starts, will be made upper block aligned. > + * len: it will be trimmed to the end of current cluster if "start + len" > + * is bigger than it. > + */ > +static int ocfs2_zeroout_partial_cluster(struct inode *inode, > + u64 start, u64 len) > +{ > + int ret; > + u64 start_block, end_block, nr_blocks; > + u64 p_block, offset; > + u32 cluster, p_cluster, nr_clusters; > + struct super_block *sb = inode->i_sb; > + u64 end = ocfs2_align_bytes_to_clusters(sb, start); > + > + if (start + len < end) > + end = start + len; > + > + start_block = ocfs2_blocks_for_bytes(sb, start); > + end_block = ocfs2_blocks_for_bytes(sb, end); > + nr_blocks = end_block - start_block; > + if (!nr_blocks) > + return 0; > + > + cluster = ocfs2_bytes_to_clusters(sb, start); > + ret = ocfs2_get_clusters(inode, cluster, &p_cluster, > + &nr_clusters, NULL); > + if (ret) > + return ret; > + if (!p_cluster) > + return 0; > + > + offset = start_block - ocfs2_clusters_to_blocks(sb, cluster); > + p_block = ocfs2_clusters_to_blocks(sb, p_cluster) + offset; > + return sb_issue_zeroout(sb, p_block, nr_blocks, GFP_NOFS); > +} > + > /* > * Parts of this function taken from xfs_change_file_space() > */ > @@ -1865,7 +1904,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode, > { > int ret; > s64 llen; > - loff_t size; > + loff_t size, orig_isize; > struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); > struct buffer_head *di_bh = NULL; > handle_t *handle; > @@ -1896,6 +1935,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode, > goto out_inode_unlock; > } > > + orig_isize = i_size_read(inode); > switch (sr->l_whence) { > case 0: /*SEEK_SET*/ > break; > @@ -1903,7 +1943,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode, > sr->l_start += f_pos; > break; > case 2: /*SEEK_END*/ > - sr->l_start += i_size_read(inode); > + sr->l_start += orig_isize; > break; > default: > ret = -EINVAL; > @@ -1957,6 +1997,11 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode, > default: > ret = -EINVAL; > } > + > + /* zeroout eof blocks in the cluster. */ > + if (!ret && change_size && orig_isize < size) > + ret = ocfs2_zeroout_partial_cluster(inode, orig_isize, > + size - orig_isize); > up_write(&OCFS2_I(inode)->ip_alloc_sem); > if (ret) { > mlog_errno(ret); >