Hi, On Thu, Oct 23, 2008 at 12:21:00PM +0200, Nick Piggin wrote: > On Thu, Oct 23, 2008 at 10:59:49AM +0100, steve@xxxxxxxxxxx wrote: > > > Btw, at least for the readpage case, a return of AOP_TRUNCATED_PAGE should > > > be checked for, which would indicate (along with !PageUptodate()) whether we > > > need to retry the read. page_mkwrite though, as you point out, is a > > > different story. > > > --Mark > > > > > Yes, and although I probably didn't make it clear I was thinking > > specifically of the page fault path there where both readpage and > > page_mkwrite hang out. > > > > Also, I've looked through all the current GFS2 code and it seems to > > be correct in relation to Miklos' point on PageUptodate() vs > > page->mapping == NULL so I don't think any changes are required there, > > but obviously that needs to be taken into account in filemap_fault wrt > > to retrying in the lock demotion case. In other words we should be > > testing for page->mapping == NULL rather than !PageUptodate() in that > > case, > > PageUptodate is OK for the filemap_fault check AFAIKS, because it does > a find_lock_page and runs the check under lock (so it can't be truncated > or invalidated), in order to prevent fault vs truncate / invalidate races. > Ah yes, I see now. Sorry, my fault (no pun intended!). Its the test after readpage that I was thinking of, for which I'd previously posted a patch under the subject "Potential fix to filemap_fault()" and you'd reponded with a more comprehensive patch, back in July, Steve. -- 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
