From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f49.google.com ([74.125.83.49]:34892 "EHLO mail-pg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932356AbcKWEr2 (ORCPT ); Tue, 22 Nov 2016 23:47:28 -0500 Received: by mail-pg0-f49.google.com with SMTP id p66so1350780pga.2 for ; Tue, 22 Nov 2016 20:47:27 -0800 (PST) Date: Tue, 22 Nov 2016 20:47:26 -0800 From: Omar Sandoval To: Anand Jain Cc: Christoph Hellwig , linux-btrfs@vger.kernel.org Subject: Re: [PATCH 6/9] btrfs: calculate end of bio offset properly Message-ID: <20161123044726.GA27107@mew> References: <1479300736-9724-1-git-send-email-hch@lst.de> <1479300736-9724-7-git-send-email-hch@lst.de> <20161118200438.GF19038@vader.DHCP.thefacebook.com> <20161122094240.GA15407@lst.de> <20161122185842.GA17735@vader.DHCP.thefacebook.com> <20161123042156.GB29697@mew> <9e59123a-7450-b7a8-bce3-e9affa7a8cd8@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <9e59123a-7450-b7a8-bce3-e9affa7a8cd8@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Wed, Nov 23, 2016 at 12:32:26PM +0800, Anand Jain wrote: > > > On 11/23/16 12:21, Omar Sandoval wrote: > > On Wed, Nov 23, 2016 at 12:21:41PM +0800, Anand Jain wrote: > > > > > > > > > > > Can anyone help me on how to get test coverage for the compression > > > > > code? > > > > > > > > I'm not surprised xfstests missed this one since it's just readahead. > > > > You might be able to get better coverage with > > > > > > > > export MOUNT_OPTS="-o compress-force" > > > > > > And where the data is /dev/urandom the btrfs compression will > > > bail out, so xfstest cases which uses /dev/urandom won't test > > > the compression code. > > > > Isn't that just with "-o compress"? That's why I recommended "-o > > compress-force". > > Nope. compress-force doesn't enforce compress even if the data > isn't compressible. I am not sure if its a bug, but its been > like that. > > The difference between compress and compress-force is that > compress-force will never give up and compress will give up > compress by setting nocompress flag if the first extent is > not compressible. > > Thanks, Anand Huh, you're right. The wording in man 5 btrfs could use some clarification. -- Omar