From: Mingming Subject: Re: [PATCH 2/2]Fix return value of splitting extents for dio write over fallocate Date: Wed, 07 Oct 2009 11:50:29 -0700 Message-ID: <1254941429.18662.8.camel@mingming-laptop> References: <1254936214.18662.7.camel@mingming-laptop> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: ext4 development , Curt Wohlgemuth To: tytso@mit.edu Return-path: Received: from e31.co.us.ibm.com ([32.97.110.149]:34619 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753470AbZJGSvZ (ORCPT ); Wed, 7 Oct 2009 14:51:25 -0400 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by e31.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id n97IiMuc024445 for ; Wed, 7 Oct 2009 12:44:22 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n97IoVu0163150 for ; Wed, 7 Oct 2009 12:50:40 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n97IoU1f019421 for ; Wed, 7 Oct 2009 12:50:30 -0600 In-Reply-To: <1254936214.18662.7.camel@mingming-laptop> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, 2009-10-07 at 10:23 -0700, Mingming wrote: > ext4: Fix return value of splitting extents for dio write over fallocate Please pick up this patch instead, after fixing compile warning. ext4: Fix return value of splitting extents for dio write over fallocate To prepare direct IO write, we need to split the unwritten extents before submit the IO. In case of no split needs at all, ext4_split_unwritten_extents() was incorrectly returns 0 instead of the size of uninitalized extents. This bug caused wrong return value sent back to VFS code when it gets called from async IO path, leads to falling back to buffered IO. Signed-off-by: Mingming Cao --- fs/ext4/extents.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) Index: linux-2.6.31-rc4/fs/ext4/extents.c =================================================================== --- linux-2.6.31-rc4.orig/fs/ext4/extents.c +++ linux-2.6.31-rc4/fs/ext4/extents.c @@ -2788,6 +2788,8 @@ fix_extent_len: * into three uninitialized extent(at most). After IO complete, the part * being filled will be convert to initialized by the end_io callback function * via ext4_convert_unwritten_extents(). + * + * Returns the size of unitialized extent to be writen, on success. */ static int ext4_split_unwritten_extents(handle_t *handle, struct inode *inode, @@ -2805,7 +2807,6 @@ static int ext4_split_unwritten_extents( unsigned int allocated, ee_len, depth; ext4_fsblk_t newblock; int err = 0; - int ret = 0; unsigned int newdepth; ext_debug("ext4_split_unwritten_extents: inode %lu," @@ -2829,7 +2830,7 @@ static int ext4_split_unwritten_extents( * uninitialized extent */ if (allocated <= max_blocks) - return ret; + return allocated; err = ext4_ext_get_access(handle, inode, path + depth); if (err)