From: =?ISO-8859-15?Q?Luk=E1=A8_Czerner?= Subject: Re: [PATCH 08/31] libext2fs: Fix off-by-one error in file truncation Date: Mon, 7 Oct 2013 16:02:05 +0200 (CEST) Message-ID: References: <20131001012642.28415.89353.stgit@birch.djwong.org> <20131001012734.28415.45404.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: tytso@mit.edu, linux-ext4@vger.kernel.org To: "Darrick J. Wong" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32523 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755234Ab3JGOCM (ORCPT ); Mon, 7 Oct 2013 10:02:12 -0400 In-Reply-To: <20131001012734.28415.45404.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, 30 Sep 2013, Darrick J. Wong wrote: > Date: Mon, 30 Sep 2013 18:27:34 -0700 > From: Darrick J. Wong > To: tytso@mit.edu, darrick.wong@oracle.com > Cc: linux-ext4@vger.kernel.org > Subject: [PATCH 08/31] libext2fs: Fix off-by-one error in file truncation > > When told to truncate a file, ext2fs_file_set_size2 should start with the first > block past the end of the file. The current calculation jumps one more block > ahead, with the result that it fails to hack off the last block. Adding > blocksize-1 and dividing is sufficient to find the last block. Looks good. Reviewed-by: Lukas Czerner > > Signed-off-by: Darrick J. Wong > --- > lib/ext2fs/fileio.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > > diff --git a/lib/ext2fs/fileio.c b/lib/ext2fs/fileio.c > index ae5cbf1..d875630 100644 > --- a/lib/ext2fs/fileio.c > +++ b/lib/ext2fs/fileio.c > @@ -384,10 +384,10 @@ errcode_t ext2fs_file_set_size2(ext2_file_t file, ext2_off64_t size) > EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE); > > truncate_block = ((size + file->fs->blocksize - 1) >> > - EXT2_BLOCK_SIZE_BITS(file->fs->super)) + 1; > + EXT2_BLOCK_SIZE_BITS(file->fs->super)); > old_size = EXT2_I_SIZE(&file->inode); > old_truncate = ((old_size + file->fs->blocksize - 1) >> > - EXT2_BLOCK_SIZE_BITS(file->fs->super)) + 1; > + EXT2_BLOCK_SIZE_BITS(file->fs->super)); > > /* If we're writing a large file, set the large_file flag */ > if (LINUX_S_ISREG(file->inode.i_mode) && > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >