1 files changed, 21 insertions, 1 deletions

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 37a34c2c622a..77720f89c879 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -108,6 +108,7 @@ struct connection {
 #define CF_INIT_PENDING 4
 #define CF_IS_OTHERCON 5
 #define CF_CLOSE 6
+#define CF_APP_LIMITED 7
         struct list_head writequeue;  /* List of outgoing writequeue_entries */
         spinlock_t writequeue_lock;
         int (*rx_action) (struct connection *); /* What to do when active */
@@ -295,7 +296,17 @@ static void lowcomms_write_space(struct sock *sk)
 {
         struct connection *con = sock2con(sk);
 
-        if (con && !test_and_set_bit(CF_WRITE_PENDING, &con->flags))
+        if (!con)
+                return;
+
+        clear_bit(SOCK_NOSPACE, &con->sock->flags);
+
+        if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
+                con->sock->sk->sk_write_pending--;
+                clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags);
+        }
+
+        if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
                 queue_work(send_workqueue, &con->swork);
 }
 
@@ -1319,6 +1330,15 @@ static void send_to_sock(struct connection *con)
                         ret = kernel_sendpage(con->sock, e->page, offset, len,
                                               msg_flags);
                         if (ret == -EAGAIN || ret == 0) {
+                                if (ret == -EAGAIN &&
+                                    test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) &&
+                                    !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
+                                        /* Notify TCP that we're limited by the
+                                         * application window size.
+                                         */
+                                        set_bit(SOCK_NOSPACE, &con->sock->flags);
+                                        con->sock->sk->sk_write_pending++;
+                                }
                                 cond_resched();
                                 goto out;
                         }