From: Jan Kara Subject: [PATCH 3/7] ext2: Avoid DAX zeroing to corrupt data Date: Wed, 11 May 2016 11:58:49 +0200 Message-ID: <1462960733-29634-4-git-send-email-jack@suse.cz> References: <1462960733-29634-1-git-send-email-jack@suse.cz> Cc: Ted Tso , linux-ext4@vger.kernel.org, Vishal Verma , Ross Zwisler , Dan Williams , linux-fsdevel@vger.kernel.org, Jan Kara To: linux-nvdimm@lists.01.org Return-path: In-Reply-To: <1462960733-29634-1-git-send-email-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Currently ext2 zeroes any data blocks allocated for DAX inode however it still returns them as BH_New. Thus DAX code zeroes them again in dax_insert_mapping() which can possibly overwrite the data that has been already stored to those blocks by a racing dax_io(). Avoid marking pre-zeroed buffers as new. Reviewed-by: Ross Zwisler Signed-off-by: Jan Kara --- fs/ext2/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 6bd58e6ff038..1f07b758b968 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -745,11 +745,11 @@ static int ext2_get_blocks(struct inode *inode, mutex_unlock(&ei->truncate_mutex); goto cleanup; } - } + } else + set_buffer_new(bh_result); ext2_splice_branch(inode, iblock, partial, indirect_blks, count); mutex_unlock(&ei->truncate_mutex); - set_buffer_new(bh_result); got_it: map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key)); if (count > blocks_to_boundary) -- 2.6.6