From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Fasheh Date: Tue Nov 20 15:00:54 2007 Subject: [Ocfs2-devel] [PATCH 1/2] Initalize bitmap_cpg of ocfs2_super to be the maximum,take 1 In-Reply-To: <20071116084110.GA3893@tma-pc1.cn.oracle.com> References: <20071116082736.GA3732@tma-pc1.cn.oracle.com> <20071116084110.GA3893@tma-pc1.cn.oracle.com> Message-ID: <20071120225859.GG28607@ca-server1.us.oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com On Fri, Nov 16, 2007 at 04:41:10PM +0800, tao.ma wrote: > This value is initialized from global_bitmap->id2.i_chain.cl_cpg. If there > is only 1 group, it will be equal to the total clusters in the volume. So > as for online resize, it should change for all the nodes in the cluster. > It isn't easy and there is no corresponding lock for it. Yeah, there's little point in having it that way. We probably want to update mkfs.ocfs2 to write out the correct value. > bitmap_cpg is only used in 2 areas: > 1. Check whether the suballoc is too large for us to allocate from the global > bitmap, so it is little used. And now the suballoc size is 2048, it rarely > meet this situation and the check is almost useless. > 2. Calculate which group a cluster belongs to. We use it during truncate to > figure out which cluster group an extent belongs too. But we should be OK > if we increase it though as the cluster group calculated shouldn't change > and we only ever have a small bitmap_cpg on file systems with a single > cluster group. Did you test a very large extend on a very small (less than 1 cluster group) file system? --Mark -- Mark Fasheh Senior Software Developer, Oracle mark.fasheh@oracle.com