On Wed, Sep 09, 2009 at 09:37:29AM -0400, Chris Mason wrote: > On Wed, Sep 09, 2009 at 03:34:35PM +0200, Nick Piggin wrote: > > Which cases do set_page_dirty happen without page_mkwrite? For fsx-linux > > I hope there shouldn't be any... > > I've been assuming its the zap_pte_range part, but now I have enough > code around it to make stack traces.
OK, because AFAIK we're _supposed_ to be able to close all that up since the last round of page_mkwrite fixes here, so pte state will not be out of state with page state. Yes set_page_dirty still gets called there, for fses without page_mkwrite or which don't try hard to keep in sync. But if you return with the page locked from page_mkwrite, this set_page_diryt call should always find the page dirty (I hope). > > but one issue with btrfs's page_mkwrite > > is that it still unlocks the page before page_mkwrite returns so if it > > is anything like other filesystems, the page might get written out > > between the page_mkwrite and the page fault's subsequent set_page_dirty. > > > > So if that race is hitting, it might appear like set_page_dirty is > > being called without a page_mkwrite. > > Good point, I'll make sure. Though if it has exposed a bug, that's a good thing too; you still want to handle that case (for now) due to the get_uesr_pages problem. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
