From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: [PATCH 0/5] btrfs: Add lzo compression support Date: Tue, 26 Oct 2010 10:34:30 +0800 Message-ID: <4CC63E36.8050105@cn.fujitsu.com> References: <4CC52D9A.3030709@cn.fujitsu.com> <20101026021341.GW18818@think> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: Chris Mason , linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <20101026021341.GW18818@think> List-ID: Chris Mason wrote: > On Mon, Oct 25, 2010 at 03:11:22PM +0800, Li Zefan wrote: >> Lzo is a much faster compression algorithm than gzib, so would allow >> more users to enable transparent compression, and some users can >> choose from compression ratio and compression speed. > > This is also much smaller than I expected, really nice. It looks like > older kernels won't properly deal (nicely give EIO) with lzo compressed > files? > > We can add compatbits to deal with that if it is the case. > I forgot compatibility issue with older kernels.. Though I didn't test older kernels, I don't think they can deal with lzo compressed files properly, at least not for inlined extents, in which case I think btrfs will just show compressed data to the users. So yes, an incompat flag is needed.