vfs: pagecache usage optimization for pagesize!=blocksize

[safe/jmp/linux-2.6] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 5de7633..42bbc69 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1023,8 +1023,17 @@ find_page:
                                        ra, filp, page,
                                        index, last_index - index);
                }
-               if (!PageUptodate(page))
-                       goto page_not_up_to_date;
+               if (!PageUptodate(page)) {
+                       if (inode->i_blkbits == PAGE_CACHE_SHIFT ||
+                                       !mapping->a_ops->is_partially_uptodate)
+                               goto page_not_up_to_date;
+                       if (TestSetPageLocked(page))
+                               goto page_not_up_to_date;
+                       if (!mapping->a_ops->is_partially_uptodate(page,
+                                                               desc, offset))
+                               goto page_not_up_to_date_locked;
+                       unlock_page(page);
+               }
 page_ok:
                /*
                 * i_size must be checked after we know the page is Uptodate.
@@ -1094,6 +1103,7 @@ page_not_up_to_date:
                if (lock_page_killable(page))
                        goto readpage_eio;
 
+page_not_up_to_date_locked:
                /* Did it get truncated before we got the lock? */
                if (!page->mapping) {
                        unlock_page(page);