From: Greg KH Subject: [patch 85/87] ext4: Use a fake block number for delayed new buffer_head Date: Tue, 09 Jun 2009 02:40:13 -0700 Message-ID: <20090609094112.328089030@blue.kroah.org> References: <20090609093848.204935043@blue.kroah.org> Cc: Justin Forbes , Zwane Mwaikambo , Theodore Ts'o , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, linux-ext4@vger.kernel.org, "Aneesh Kumar K.V" , Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@kernel.org Return-path: Received: from kroah.org ([198.145.64.141]:32919 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758608AbZFIKW0 (ORCPT ); Tue, 9 Jun 2009 06:22:26 -0400 Content-Disposition: inline; filename=ext4-use-a-fake-block-number-for-delayed-new-buffer_head.patch In-Reply-To: <20090609094451.GA26439@kroah.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 2.6.29-stable review patch. If anyone has any objections, please let us know. ------------------ From: Aneesh Kumar K.V (cherry picked from commit 33b9817e2ae097c7b8d256e3510ac6c54fc6d9d0) Use a very large unsigned number (~0xffff) as as the fake block number for the delayed new buffer. The VFS should never try to write out this number, but if it does, this will make it obvious. Signed-off-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2220,6 +2220,10 @@ static int ext4_da_get_block_prep(struct struct buffer_head *bh_result, int create) { int ret = 0; + sector_t invalid_block = ~((sector_t) 0xffff); + + if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es)) + invalid_block = ~0; BUG_ON(create == 0); BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize); @@ -2241,7 +2245,7 @@ static int ext4_da_get_block_prep(struct /* not enough space to reserve */ return ret; - map_bh(bh_result, inode->i_sb, 0); + map_bh(bh_result, inode->i_sb, invalid_block); set_buffer_new(bh_result); set_buffer_delay(bh_result); } else if (ret > 0) {