nfs/flexfiles: Use the layout segment for reading unless it a IOMODE_RW and reading is disabled

Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -830,7 +830,8 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 	int ds_idx;
 
 	/* Use full layout for now */
-	if (!pgio->pg_lseg) {
+	if (!pgio->pg_lseg || ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
+		pnfs_put_lseg(pgio->pg_lseg);
 		pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 						   req->wb_context,
 						   0,
@@ -840,9 +841,9 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 		if (IS_ERR(pgio->pg_lseg)) {
 			pgio->pg_error = PTR_ERR(pgio->pg_lseg);
 			pgio->pg_lseg = NULL;
-			return;
 		}
 	}
+
 	/* If no lseg, fall back to read through mds */
 	if (pgio->pg_lseg == NULL)
 		goto out_mds;