From: "Aneesh Kumar K.V" Subject: [PATCH -V2] Fix sub-block zeroing for buffered writes into unwritten extents. Date: Tue, 28 Apr 2009 09:43:47 +0530 Message-ID: <1240892027-6481-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: linux-ext4@vger.kernel.org, "Aneesh Kumar K.V" To: cmm@us.ibm.com, tytso@mit.edu, sandeen@redhat.com Return-path: Received: from e23smtp03.au.ibm.com ([202.81.31.145]:57683 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751350AbZD1ENz (ORCPT ); Tue, 28 Apr 2009 00:13:55 -0400 Received: from d23relay02.au.ibm.com (d23relay02.au.ibm.com [202.81.31.244]) by e23smtp03.au.ibm.com (8.13.1/8.13.1) with ESMTP id n3S4C0Iq014981 for ; Tue, 28 Apr 2009 14:12:00 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay02.au.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n3S4DrQG1089784 for ; Tue, 28 Apr 2009 14:13:53 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n3S4DqxZ019826 for ; Tue, 28 Apr 2009 14:13:53 +1000 Sender: linux-ext4-owner@vger.kernel.org List-ID: We need to mark the buffer_head mapping prealloc space as new during write_begin. Otherwise we don't zero out the page cache content properly for a partial write. This will cause file corruption with preallocation. Signed-off-by: Aneesh Kumar K.V --- fs/ext4/inode.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c6bd6ce..8dfa97a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2323,6 +2323,14 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock, set_buffer_delay(bh_result); } else if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); + bh_result->b_bdev = inode->i_sb->s_bdev; + /* + * With sub-block writes into unwritten extents + * we also need to mark the buffer as new so that + * the unwritten parts of the buffer gets correctly zeroed. + */ + if (buffer_unwritten(bh_result)) + set_buffer_new(bh_result); ret = 0; } -- tg: (51bec03..) preallocate_corruption (depends on: ext4_lock_group_conversion)