fs: dlm: check for pending users filling buffers

Currently we don't care if the DLM application stack is filling buffers
(not committed yet) while we transmit some already committed buffers.
By checking on active writequeue users before dequeue a writequeue entry
we know there is coming more data and do nothing. We wait until the send
worker will be triggered again if the writequeue entry users hit zero.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index f7fc1ac76ce83a5f250852f70783df2e724df5d1..6d500ebc614533551f0f609342bb890761741fea 100644 (file)
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -201,7 +201,10 @@ static struct writequeue_entry *con_next_wq(struct connection *con)
 
        e = list_first_entry(&con->writequeue, struct writequeue_entry,
                             list);
-       if (e->len == 0)
+       /* if len is zero nothing is to send, if there are users filling
+        * buffers we wait until the users are done so we can send more.
+        */
+       if (e->users || e->len == 0)
                return NULL;
 
        return e;