From: Liu Bo Subject: [PATCH] E2fsprogs/filefrag: fix filefrag regression Date: Thu, 14 Jun 2012 16:44:46 +0800 Message-ID: <1339663486-5417-1-git-send-email-liubo2009@cn.fujitsu.com> To: Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:37455 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751485Ab2FNIhT (ORCPT ); Thu, 14 Jun 2012 04:37:19 -0400 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id q5E8bGUQ031950 for ; Thu, 14 Jun 2012 16:37:16 +0800 Sender: linux-ext4-owner@vger.kernel.org List-ID: filefrag has several bugs: 1. $ touch f1 $ filefrag f1 f1: 1 extent found ----> bug! $ filefrag -v f1 Filesystem type is: ef53 File size of f1 is 0 (0 blocks, blocksize 4096) f1: 0 extents found 2. $ truncate -s 1m f2 $ filefrag f2 f2: 1 extent found ----> bug! $ filefrag -v f2 Filesystem type is: ef53 File size of f2 is 1048576 (256 blocks, blocksize 4096) f2: 0 extents found 3. $ for i in `seq 11 -2 0`; do dd if=/dev/zero of=f4 bs=4k count=1 seek=$i conv=notrunc oflag=sync &>/dev/null; done $ ll f4 -rw-r--r-- 1 root root 49152 Jun 9 15:09 f4 $ filefrag f4 f4: 7 extents found $ filefrag -v f4 Filesystem type is: ef53 File size of f4 is 49152 (12 blocks, blocksize 4096) ext logical physical expected length flags 0 1 1109993 1 1 3 1109992 1109994 1 2 5 1109991 1109993 1 3 7 1109990 1109992 1 4 9 1109989 1109991 1 5 11 1108207 1109990 1 eof f4: 7 extents found --------------------------> but we only have 6 extents, bug! All of these bugs come from the fact that we've made a mistake on calculating total extents: o we set 1 as default for 'total extents', and this will report 1 extent found even when we don't get any extent from fiemap. o if our first extent does not start from 0(logical addr), total extents will be one more than what it should be. Signed-off-by: Liu Bo --- misc/filefrag.c | 25 ++++++++++--------------- 1 files changed, 10 insertions(+), 15 deletions(-) diff --git a/misc/filefrag.c b/misc/filefrag.c index 0583e91..af008fb 100644 --- a/misc/filefrag.c +++ b/misc/filefrag.c @@ -175,7 +175,7 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents) unsigned int i; static int fiemap_incompat_printed; int fiemap_header_printed = 0; - int tot_extents = 1, n = 0; + int tot_extents = 0, n = 0; int last = 0; int rc; @@ -201,25 +201,17 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents) return rc; } + /* If 0 extents are returned, then more ioctls are not needed */ + if (fiemap->fm_mapped_extents == 0) + break; + if (verbose && !fiemap_header_printed) { - /* - * No extents on first call? - * Skip header and show 0 extents. - */ - if (fiemap->fm_mapped_extents == 0) { - *num_extents = 0; - goto out; - } printf(" ext %*s %*s %*s length flags\n", logical_width, "logical", physical_width, "physical", physical_width, "expected"); fiemap_header_printed = 1; } - /* If 0 extents are returned, then more ioctls are not needed */ - if (fiemap->fm_mapped_extents == 0) - break;