From: Peng Tao Subject: [PATCH-e2fsprogs-resend] filefrag: fix fm_start in filefrag_fiemap loop Date: Thu, 4 Jun 2009 09:18:40 +0800 Message-ID: <1244078320-13888-1-git-send-email-bergwolf@gmail.com> Cc: Theodore Tso , Andreas Dilger , Peng Tao To: linux-ext4@vger.kernel.org Return-path: Received: from mail-px0-f182.google.com ([209.85.216.182]:42107 "EHLO mail-px0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751512AbZFDBTL (ORCPT ); Wed, 3 Jun 2009 21:19:11 -0400 Received: by pxi12 with SMTP id 12so410442pxi.33 for ; Wed, 03 Jun 2009 18:19:12 -0700 (PDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: When used with -v and the targeted file has more than 144 extents(double of the length of fm_extents array provided by buf), filefrag_fiemap loops and calls fiemap ioctl() multiple times to calculate the actual number of extents in a file. Each call to fiemap ioctl() uses fm_start as the starting logical offset. The patch fixes fm_start in each loop( except for the first one) and makes the extent calculation correct for files with more that 144 extents. To produce the problem, first run filefrag -v on a highly fragmented file. Then change the buf size in filefrag_fiemap to make it large enough to have all the extent mapped in a single loop and run filefrag -v after recompiling. The former will produce a much smaller extent count because of the false fm_start used in the loop. And the two will produce different extent output since the 145th extent. Signed-off-by: Peng Tao --- misc/filefrag.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/misc/filefrag.c b/misc/filefrag.c index 6bea2cd..7786646 100644 --- a/misc/filefrag.c +++ b/misc/filefrag.c @@ -239,7 +239,7 @@ int filefrag_fiemap(int fd, int blk_shift, int *num_extents) n++; } - fiemap->fm_start += fm_ext[i-1].fe_logical + + fiemap->fm_start = fm_ext[i-1].fe_logical + fm_ext[i-1].fe_length; } while (last == 0); -- 1.6.2.GIT