Use writev in libfio_sec_osd

rw_blocking.cpp

@@ -50,3 +50,37 @@ int write_blocking(int fd, void *write_buf, size_t remaining)
     }
     return done;
 }
+
+int writev_blocking(int fd, iovec *iov, int iovcnt)
+{
+    int v = 0;
+    int done = 0;
+    while (v < iovcnt)
+    {
+        ssize_t r = writev(fd, iov, iovcnt);
+        if (r < 0)
+        {
+            if (errno != EAGAIN && errno != EPIPE)
+            {
+                perror("writev");
+                exit(1);
+            }
+            continue;
+        }
+        while (v < iovcnt)
+        {
+            if (iov[v].iov_len > r)
+            {
+                iov[v].iov_len -= r;
+                iov[v].iov_base += r;
+                break;
+            }
+            else
+            {
+                v++;
+            }
+        }
+        done += r;
+    }
+    return done;
+}