fs: block_page_mkwrite should wait for writeback to finish

Darrick J. Wong · Al Viro · commit d76ee18a8551 · 2011-05-28T01:03:21.000-04:00
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 &lt;djwong@us.ibm.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
diff --git 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);

Original file line number	Diff line number	Diff line change
`@@ -2382,6 +2382,7 @@ int __block_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf,`
`2382`	`2382`	`ret = -EAGAIN;`
`2383`	`2383`	`goto out_unlock;`
`2384`	`2384`	`}`
	`2385`	`+ wait_on_page_writeback(page);`
`2385`	`2386`	`return 0;`
`2386`	`2387`	`out_unlock:`
`2387`	`2388`	`unlock_page(page);`