From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id E57E07F8D for ; Mon, 18 Mar 2013 12:35:06 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay1.corp.sgi.com (Postfix) with ESMTP id CAB9F8F8035 for ; Mon, 18 Mar 2013 10:35:06 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id aG7ilyQixTvxjylR for ; Mon, 18 Mar 2013 10:35:06 -0700 (PDT) Message-ID: <51475043.4010505@redhat.com> Date: Mon, 18 Mar 2013 12:34:59 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: possible dev branch regression - xfstest 285/1k References: <20130315222818.GA16100@wallace> <20130316150923.GA18589@gmail.com> <20130317030648.GA14225@thunk.org> <51473C8B.5070509@redhat.com> <20130318170927.GA5639@thunk.org> In-Reply-To: <20130318170927.GA5639@thunk.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Theodore Ts'o Cc: xfs-oss , linux-ext4@vger.kernel.org, Eric Whitney On 3/18/13 12:09 PM, Theodore Ts'o wrote: > On Mon, Mar 18, 2013 at 11:10:51AM -0500, Eric Sandeen wrote: >> The test could do this too, right? >> >> _need_to_be_root >> >> and: >> >> if [ "$FSTYP" == "ext4" ]; then >> ORIG_ZEROOUT_KB=`cat /sys/fs/ext4/$TEST_DEV/extent_max_zeroout_kb` >> echo 0 > /sys/fs/ext4/$TEST_DEV/extent_max_zeroout_kb >> fi >> >> and put it back to default in _cleanup: >> >> echo $ORIG_ZEROOUT_KB > /sys/fs/ext4/$TEST_DEV/extent_max_zeroout_kb >> >> That way we'd be testing seek hole correctness w/o being subject to >> the vagaries in allocator behavior. > > Yeah, the question is whether it would be more acceptable to put > ext4-specific hacks like this into the test, or to modify > src/seek_sanity_test.c so that it writes the test block-size block > using pwrite at offset blocksize*42 instead of offset blocksize*10. That seems like more of an obtuse hack, since it depends on current default behavior, right? Explicitly setting the zeroout to 0, with a comment as to why, should make it clear to the reader of the test I think. I'll have to look, xfs speculative preallocation fills in holes in some cases as well, I'm not certain how it behaves on this test. But we could put in a specific tuning for xfs as well if needed. If it becomes clear that every fs requires tuning to not opportunistically fill in holes, then maybe we should make it non-generic, and only support filesystems we've tested or tuned to work with the testcase. > I had assumed putting hacks which tweaked sysfs tunables into the > xfstest script itself would be frowned upon, but if that's considered > OK, that would be great. I don't see any real problem with it, myself. cc: xfs list to see if there are any objections... -Eric > > - Ted > _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs