GIT: unionfs2-2.6.27.y: Unionfs: mmap fixes to unionfs_writepage

[Erez Zadok]

commit 28c8ddaf6825ef7d0cc2243bb9de78b6099270bb
Author: Erez_Zadok <ezk at cs.sunysb.edu>
Date:   Tue Jul 31 19:25:55 2007 -0400

    Unionfs: mmap fixes to unionfs_writepage
    
    Don't call unlock_page on lower_page unless lower ->writepage failed.
    
    Signed-off-by: Erez Zadok <ezk at cs.sunysb.edu>

diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
index 145ba5b..8b04a46 100644
--- a/fs/unionfs/mmap.c
+++ b/fs/unionfs/mmap.c
@@ -110,8 +110,9 @@ static int unionfs_writepage(struct page *page, struct writeback_control *wbc)
 	err = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
 	wbc->for_writepages = saved_for_writepages; /* restore value */
 
-	/* b/c find_lock_page locked it */
-	unlock_page(lower_page);
+	/* b/c find_lock_page locked it and ->writepage unlocks on success */
+	if (err)
+		unlock_page(lower_page);
 	/* b/c grab_cache_page increased refcnt */
 	page_cache_release(lower_page);