From: Lukas Czerner Subject: Re: [PATCH] ext4: avoid redundant cache finding if flags not cantian PUNCH_OUT Date: Mon, 27 Jun 2011 12:15:00 +0200 (CEST) Message-ID: References: <1309156420-4201-1-git-send-email-sanbai@taobao.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: linux-ext4@vger.kernel.org, Robin Dong To: Robin Dong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:11091 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757311Ab1F0KPJ (ORCPT ); Mon, 27 Jun 2011 06:15:09 -0400 In-Reply-To: <1309156420-4201-1-git-send-email-sanbai@taobao.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, 27 Jun 2011, Robin Dong wrote: > In old code, ext4 will find extent in cache first even flags does > not contian PUNCH_OUT, that may waste some time. > > Signed-off-by: Robin Dong > --- > fs/ext4/extents.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index eb63c7b..d583ec3 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3358,8 +3358,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, > trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); > > /* check in cache */ > - if (ext4_ext_in_cache(inode, map->m_lblk, &newex) && > - ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) { > + if (((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) && > + ext4_ext_in_cache(inode, map->m_lblk, &newex)) { Hi Robin, The patch is good thanks, but I think that this: if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) && ext4_ext_in_cache(inode, map->m_lblk, &newex)) { looks better. Thanks! -Lukas > if (!newex.ee_start_lo && !newex.ee_start_hi) { > if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { > /* >