On Wed, 2009-04-29 at 22:04 +0200, Jan Kara wrote: > > What we don't want to do is have a call to write() over existing blocks > > in the file add new things to the data=ordered list. I don't see how we > > can avoid that without datanew. > Yes, what I suggest would do exactly that: > In ordered_writepage() in the beginning we do: > page_bufs = page_buffers(page); > if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE, > NULL, buffer_unmapped)) { > return block_write_full_page(page, NULL, wbc); > } > So we only get to starting a transaction and file some buffers if some buffer > in the page is unmapped. Write() maps / allocates all buffers in write_begin() > so they are never added to ordered lists in writepage(). Right, writepage doesn't really need datanew. > We rely on write_end > to do it. So the only case where not all buffers in the page are mapped is > when we have to allocate in writepage() (mmaped write) or the two cases I > describe above. But I still think write_end does need datanew. That's where 99% of the ordered buffers are going to come from when we overwrite the contents of an existing file. -chris -- 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