From: Allison Henderson Subject: Re: xfsprogs: Fix for xfstest 252 hang on ext4 Date: Mon, 23 May 2011 19:38:04 -0700 Message-ID: <4DDB1A0C.5030502@linux.vnet.ibm.com> References: <4DDAC4EF.1050702@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: xfs-oss , Ext4 Developers List To: Yongqiang Yang Return-path: Received: from e7.ny.us.ibm.com ([32.97.182.137]:48111 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752046Ab1EXCiR (ORCPT ); Mon, 23 May 2011 22:38:17 -0400 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by e7.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p4O2ErKa030515 for ; Mon, 23 May 2011 22:14:53 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p4O2cGEE115438 for ; Mon, 23 May 2011 22:38:16 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p4O2cGau010642 for ; Mon, 23 May 2011 22:38:16 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 5/23/2011 6:16 PM, Yongqiang Yang wrote: > On Tue, May 24, 2011 at 4:34 AM, Allison Henderson > wrote: >> Hi all, >> >> While trying to add more punch hole tests to xfstest, I found that test 252 hangs on ext4 due to a loop in xfsprogs that does not exit. XFS gets out of this loop because there is logic in the loop that looks for the last extent flag and breaks out. But it looks like ext4 does not return a last extent when the file has a hole at the end. I am not sure if this is the correct behavior or not, so I will copy the ext4 folks on this too. Below is a copy of the fix for xfsprogs: > > Hi there, > > What's blocksize of the tested ext4? For now, ext4 returns > LAST_EXTENT if the logical offset covered by the extent is greater > than file size, so if there is a hole at the end, no last extent is > returned. Thx! > > Yongqiang. Hi there, The block size I've been using is 4096. As long as that behavior is expected, I think the test will be ok with just the xfsprogs fix, though. Thx! Allison Henderson > >> >> diff --git a/io/fiemap.c b/io/fiemap.c >> index fa990cc..81fc92c 100644 >> --- a/io/fiemap.c >> +++ b/io/fiemap.c >> @@ -246,7 +246,7 @@ fiemap_f( >> flg_w, _("FLAGS")); >> } >> >> - while (!last&& ((cur_extent + 1) != max_extents)) { >> + while (!last&& (cur_extent<= max_extents)) { >> if (max_extents) >> num_extents = min(num_extents, >> max_extents - (cur_extent + 1)); >> >> >> It looks like the loop enters with last=0, cur_extents=0, and max_extents = 0, and on the first iteration cur_extents get set to 2, so we dont see ((cur_extent + 1) == max_extents for a very long time. I doubt the logic was meant to work that way, so this patch should fix it, but I wanted to make sure that the fiemap for ext4 is working as intended too. Feed back appreciated! Thx all! >> >> Allison Henderson >> -- >> 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 >> > > >