From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934025AbXKOHM2 (ORCPT ); Thu, 15 Nov 2007 02:12:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932926AbXKOGxW (ORCPT ); Thu, 15 Nov 2007 01:53:22 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:33541 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765378AbXKOGxU (ORCPT ); Thu, 15 Nov 2007 01:53:20 -0500 Date: Wed, 14 Nov 2007 22:52:37 -0800 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Mark Fasheh Subject: [patch 2/3] ocfs2: fix write() performance regression Message-ID: <20071115065237.GC20690@kroah.com> References: <20071115065014.785638308@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="ocfs2-fix-write-performance-regression.patch" In-Reply-To: <20071115065220.GA20690@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -stable review patch. If anyone has any objections, please let us know. ------------------ From: Mark Fasheh patch 4e9563fd55ff4479f2b118d0757d121dd0cfc39c in mainline. ocfs2: fix write() performance regression On file systems which don't support sparse files, Ocfs2_map_page_blocks() was reading blocks on appending writes. This caused write performance to suffer dramatically. Fix this by detecting an appending write on a nonsparse fs and skipping the read. Signed-off-by: Mark Fasheh Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/aops.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -661,6 +661,27 @@ static void ocfs2_clear_page_regions(str } /* + * Nonsparse file systems fully allocate before we get to the write + * code. This prevents ocfs2_write() from tagging the write as an + * allocating one, which means ocfs2_map_page_blocks() might try to + * read-in the blocks at the tail of our file. Avoid reading them by + * testing i_size against each block offset. + */ +static int ocfs2_should_read_blk(struct inode *inode, struct page *page, + unsigned int block_start) +{ + u64 offset = page_offset(page) + block_start; + + if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) + return 1; + + if (i_size_read(inode) > offset) + return 1; + + return 0; +} + +/* * Some of this taken from block_prepare_write(). We already have our * mapping by now though, and the entire write will be allocating or * it won't, so not much need to use BH_New. @@ -713,6 +734,7 @@ int ocfs2_map_page_blocks(struct page *p set_buffer_uptodate(bh); } else if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_new(bh) && + ocfs2_should_read_blk(inode, page, block_start) && (block_start < from || block_end > to)) { ll_rw_block(READ, 1, &bh); *wait_bh++=bh; --