Messages in this thread | | | Subject | Re: 2.4.0-test10-pre3:Oops in mm/filemap.c:filemap_write_pa | From | Trond Myklebust <> | Date | 20 Oct 2000 03:28:03 +0200 |
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>>>>> " " == Linus Torvalds <torvalds@transmeta.com> writes:
> 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.
<snip> > 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);
The problem here is that NFS pages have 3 rather than 2 states: 1) mmapped & correct. 2) mmapped & incorrect. (but possibly dirty) 3) Unmapped
For case 1), we clearly want to have the page in inode->i_mapping. For cases 2) & 3) we don't.
However for case 2) we still have a weak association to the inode itself, and we want to be able to reference inode metadata etc. Would it make sense then to remove these pages from i_mapping, but to hang them onto a new struct address_space (call it i_unmapped for want of a better name)?
That would allow you to keep a consistent state for the page, while still allowing you to 'invalidate' it (by removing it from the i_mapping) and hence maintain a consistent cache.
invalidate_inode_pages() would then reduce to
remove_page_from_inode_queue(page); remove_page_from_hash_queue(page); if (page_count(page)) add_page_to_inode_unmapped(page);
Cheers, Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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