On Tue, 2008-04-15 at 18:14 +0200, Jan Kara wrote: > Hi, > > I've ported my patch inversing locking ordering of page_lock and > transaction start to ext4 (on top of ext4 patch queue). Everything except > delayed allocation is converted (the patch is below for interested > readers). The question is how to proceed with delayed allocation. Its > current implementation in VFS is designed to work well with the old > ordering (page lock first, then start a transaction). We could bend it to > work with the new locking ordering but I really see no point since ext4 is > the only user. I think the plan is port the changes to ext2/3/JFS and support delayed allocation on those filesystems. > Also XFS has AFAIK ordering first start transaction, then > lock pages so if we should ever merge delayed alloc implementations the new > ordering would make it easier. > So what do people think here? Do you agree with reimplementing current > mpage_da_... functions? It worth a try, but I could not see how to bend delayed allocation to work the new ordering:( With delayed allocation Ext4 gets into writepage() directly with page locked, but we need to start transaction to do block allocation...:( I guess this reserve locking ordering allows support writepages() for ext3/4? What other the benefits? Regards, Mingming -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
