pnfs: recoalesce when ld write pagelist fails

For pnfs pagelist write failure, we need to pg_recoalesce and resend IO to
mds.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Jim Rees <rees@umich.edu>
Cc: stable@kernel.org [3.0]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 72813ed..106fd06 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1166,7 +1166,13 @@
 static void nfs_writeback_release_full(void *calldata)
 {
 	struct nfs_write_data	*data = calldata;
-	int status = data->task.tk_status;
+	int ret, status = data->task.tk_status;
+	struct nfs_pageio_descriptor pgio;
+
+	if (data->pnfs_error) {
+		nfs_pageio_init_write_mds(&pgio, data->inode, FLUSH_STABLE);
+		pgio.pg_recoalesce = 1;
+	}
 
 	/* Update attributes as result of writeback. */
 	while (!list_empty(&data->pages)) {
@@ -1182,6 +1188,11 @@
 			req->wb_bytes,
 			(long long)req_offset(req));
 
+		if (data->pnfs_error) {
+			dprintk(", pnfs error = %d\n", data->pnfs_error);
+			goto next;
+		}
+
 		if (status < 0) {
 			nfs_set_pageerror(page);
 			nfs_context_set_write_error(req->wb_context, status);
@@ -1201,7 +1212,19 @@
 	next:
 		nfs_clear_page_tag_locked(req);
 		nfs_end_page_writeback(page);
+		if (data->pnfs_error) {
+			lock_page(page);
+			nfs_pageio_cond_complete(&pgio, page->index);
+			ret = nfs_page_async_flush(&pgio, page, 0);
+			if (ret) {
+				nfs_set_pageerror(page);
+				dprintk("rewrite to MDS error = %d\n", ret);
+			}
+			unlock_page(page);
+		}
 	}
+	if (data->pnfs_error)
+		nfs_pageio_complete(&pgio);
 	nfs_writedata_release(calldata);
 }