NFS: Don't call generic_error_remove_page() while holding locks

The NFS read code can trigger writeback while holding the page lock.
If an error then triggers a call to nfs_write_error_remove_page(),
we can deadlock.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/write.c

@@ -584,9 +584,8 @@ nfs_lock_and_join_requests(struct page *page)
 
 static void nfs_write_error_remove_page(struct nfs_page *req)
 {
+	SetPageError(req->wb_page);
 	nfs_end_page_writeback(req);
-	generic_error_remove_page(page_file_mapping(req->wb_page),
-				  req->wb_page);
 	nfs_release_request(req);
 }