Hi, On 10/4/06, Mark Williamson <mark.williamson@xxxxxxxxxxxx> wrote:
Hi there, I'm writing a custom filesystem that does not use a block device as it's backing store. I think it should be possible to arrange for a writepage to be called at some point after a commit_write - for instance by just dirtying the page and waiting for it to be flushed. I've tried various methods for dirtying the page, but my writepage() method never seems to get called. I can't see anything obvious that I'm missing, but most other filesystems end up calling into the block layer at some point, so they don't correspond very well to what I'm trying to do. Any suggestions or pointers would be greatly appreciated.
Well, given the information you provided it is anyone's guess, but four things came into my mind at the moment: 1) Check that you have a handler for the commit_write() address space operation. 2) Check that the handler marks the page as dirty by calling set_page_dirty(). Its variants like __set_page_dirty_buffers() and __set_page_dirty_nobuffers() may also be ok but since you are not block device based I don't think you should be using buffer_heads. Specifically SetPageDirty() is NOT enough because it does not mark the page dirty in the mapping tree (See documentation/filesystems/Locking for other details). 3) If you have your own set_page_dirty() address space operation, make sure it does the right thing by eventually calling __set_page_dirty_nobuffers() (assuming you don't use buffer heads). 4) Check that writepages() does not kick in earlier and does not do the job instead. HTH Martin Jambor - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
