Unionfs: writepage updates

Don't set/reset the PageUptodate flag on our page.  Call flush_dcache_page
on the lower page after copy_highpage, and set it uptodate.  Call
set_page_dirty right before clear_page_dirty_for_io.

CC: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
index 4b00b98eee96ab56e17c1bf56c85e1b076fbce83..468dc61b9cb10ec8261414a1227c22044cc48d75 100644 (file)
--- a/fs/unionfs/mmap.c
+++ b/fs/unionfs/mmap.c
@@ -28,6 +28,7 @@ static int unionfs_writepage(struct page *page, struct writeback_control *wbc)
        struct address_space *lower_mapping; /* lower inode mapping */
        gfp_t mask;
 
+       BUG_ON(!PageUptodate(page));
        inode = page->mapping->host;
        lower_inode = unionfs_lower_inode(inode);
        lower_mapping = lower_inode->i_mapping;
@@ -53,6 +54,8 @@ static int unionfs_writepage(struct page *page, struct writeback_control *wbc)
 
        /* copy page data from our upper page to the lower page */
        copy_highpage(lower_page, page);
+       flush_dcache_page(lower_page);
+       SetPageUptodate(lower_page);
 
        /*
         * Call lower writepage (expects locked page).  However, if we are
@@ -68,12 +71,11 @@ static int unionfs_writepage(struct page *page, struct writeback_control *wbc)
                goto out_release;
        }
        BUG_ON(!lower_mapping->a_ops->writepage);
+       set_page_dirty(lower_page);
        clear_page_dirty_for_io(lower_page); /* emulate VFS behavior */
        err = lower_mapping->a_ops->writepage(lower_page, wbc);
-       if (err < 0) {
-               ClearPageUptodate(page);
+       if (err < 0)
                goto out_release;
-       }
 
        /*
         * Lower file systems such as ramfs and tmpfs, may return
@@ -97,7 +99,7 @@ static int unionfs_writepage(struct page *page, struct writeback_control *wbc)
        }
 
        /* all is well */
-       SetPageUptodate(page);
+
        /* lower mtimes have changed: update ours */
        unionfs_copy_attr_times(inode);