NFS: Fix writepage(s) error handling to not report errors twice

If writepage()/writepages() saw an error, but handled it without
reporting it, we should not be re-reporting that error on exit.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/write.c

@@ -621,12 +621,12 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 	WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 
 	/* If there is a fatal error that covers this write, just exit */
-	ret = 0;
 	mapping = page_file_mapping(page);
-	if (test_bit(AS_ENOSPC, &mapping->flags) ||
-	    test_bit(AS_EIO, &mapping->flags))
+	ret = pgio->pg_error;
+	if (nfs_error_is_fatal_on_server(ret))
 		goto out_launder;
 
+	ret = 0;
 	if (!nfs_pageio_add_request(pgio, req)) {
 		ret = pgio->pg_error;
 		/*
@@ -638,6 +638,7 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 		} else
 			ret = -EAGAIN;
 		nfs_redirty_request(req);
+		pgio->pg_error = 0;
 	} else
 		nfs_add_stats(page_file_mapping(page)->host,
 				NFSIOS_WRITEPAGES, 1);
@@ -657,7 +658,7 @@ static int nfs_do_writepage(struct page *page, struct writeback_control *wbc,
 	ret = nfs_page_async_flush(pgio, page);
 	if (ret == -EAGAIN) {
 		redirty_page_for_writepage(wbc, page);
-		ret = 0;
+		ret = AOP_WRITEPAGE_ACTIVATE;
 	}
 	return ret;
 }
@@ -676,10 +677,11 @@ static int nfs_writepage_locked(struct page *page,
 	nfs_pageio_init_write(&pgio, inode, 0,
 				false, &nfs_async_write_completion_ops);
 	err = nfs_do_writepage(page, wbc, &pgio);
+	pgio.pg_error = 0;
 	nfs_pageio_complete(&pgio);
 	if (err < 0)
 		return err;
-	if (pgio.pg_error < 0)
+	if (nfs_error_is_fatal(pgio.pg_error))
 		return pgio.pg_error;
 	return 0;
 }
@@ -689,7 +691,8 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc)
 	int ret;
 
 	ret = nfs_writepage_locked(page, wbc);
-	unlock_page(page);
+	if (ret != AOP_WRITEPAGE_ACTIVATE)
+		unlock_page(page);
 	return ret;
 }
 
@@ -698,7 +701,8 @@ static int nfs_writepages_callback(struct page *page, struct writeback_control *
 	int ret;
 
 	ret = nfs_do_writepage(page, wbc, data);
-	unlock_page(page);
+	if (ret != AOP_WRITEPAGE_ACTIVATE)
+		unlock_page(page);
 	return ret;
 }
 
@@ -724,13 +728,14 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 				&nfs_async_write_completion_ops);
 	pgio.pg_io_completion = ioc;
 	err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
+	pgio.pg_error = 0;
 	nfs_pageio_complete(&pgio);
 	nfs_io_completion_put(ioc);
 
 	if (err < 0)
 		goto out_err;
 	err = pgio.pg_error;
-	if (err < 0)
+	if (nfs_error_is_fatal(err))
 		goto out_err;
 	return 0;
 out_err: