NFS: Don't recoalesce on error in nfs_pageio_complete_mirror()

commit 8127d82705998568b52ac724e28e00941538083d upstream.

If the I/O completion failed with a fatal error, then we should just
exit nfs_pageio_complete_mirror() rather than try to recoalesce.

Fixes: a7d42ddb3099 ("nfs: add mirroring support to pgio layer")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index e34af0f..fad4d51 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1200,7 +1200,7 @@
 		desc->pg_mirror_idx = mirror_idx;
 	for (;;) {
 		nfs_pageio_doio(desc);
-		if (!mirror->pg_recoalesce)
+		if (desc->pg_error < 0 || !mirror->pg_recoalesce)
 			break;
 		if (!nfs_do_recoalesce(desc))
 			break;