From d76ee18a8551e33ad7dbd55cac38bc7b094f3abb Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@us.ibm.com>
Date: Fri, 27 May 2011 12:23:41 -0700
Subject: [PATCH] fs: block_page_mkwrite should wait for writeback to finish

For filesystems such as nilfs2 and xfs that use block_page_mkwrite, modify that
function to wait for pending writeback before allowing the page to become
writable.  This is needed to stabilize pages during writeback for those two
filesystems.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/buffer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/buffer.c b/fs/buffer.c
index 698c6b2cc462..49c9aada0374 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2382,6 +2382,7 @@ int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 		ret = -EAGAIN;
 		goto out_unlock;
 	}
+	wait_on_page_writeback(page);
 	return 0;
 out_unlock:
 	unlock_page(page);
-- 
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