In article <[EMAIL PROTECTED]>,
Trond Myklebust  <[EMAIL PROTECTED]> wrote:
>>>>>> " " == Petr Vandrovec <[EMAIL PROTECTED]> writes:
>
>     > You do not have to use NFS - look for my postings with
>     > 'page->mapping == NULL' in archive. Your code uses shared mmap,
>     > 'page->isn't
>     > it? Probably shared by couple of processes.
>
>It's probably particularly nasty under NFS because of
>invalidate_inode_pages().

Btw, that "invalidate_inode_pages()" thing is just wrong - we can't just
remove pages that are mapped etc, because that would result in no end of
fun aliasing problems etc.

I don't see why invalidate_inode_pages() would be called for this
sequence, though, which is why I'd be more likely to blame the truncate
case, but I think you're right about invalidate_inode_pages() being a
problem none-the-less.

How about adding a test in invalidate_inode_pages() like

                /* We cannot invalidate a locked page */
                if (TryLockPage(page))
                        continue;

+               /* We cannot invalidate a page that is in use */
+               if (page_count(page) != 1) {
+                       UnlockPage(page);
+                       continue;
+               }
+
                __lru_cache_del(page);
                __remove_inode_page(page);

Because otherwise we might end up invalidating pages that might have
pending write-back etc (although I think the NFS logic tries to avoid
invalidating when there's pending activity).

                Linus
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