features/changelog: Barrier in changelog during snapshot.

        Changelog barriers unlink, rename, rmdir fops on barrier 'on'
        notification from glusterfsd mgmt layer and unbarriers the
        same on barrier 'off' notification during snapshot.

        Please see the following link for more details.
        http://www.gluster.org/community/documentation/index.php/Changelog_Design_changes_for_snapshot

Signed-off-by: Kotresh H R <khiremat@redhat.com>

Change-Id: Iea9c62fafc86242f9404e03679b1941aa9c88c9a
Signed-off-by: Kotresh H R <khiremat@redhat.com>
Reviewed-on: http://review.gluster.org/7415
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Reviewed-by: Varun Shastry <vshastry@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/xlators/features/changelog/src/changelog-barrier.c b/xlators/features/changelog/src/changelog-barrier.c
new file mode 100644
index 00000000000..c20eed85b1c
--- /dev/null
+++ b/xlators/features/changelog/src/changelog-barrier.c
@@ -0,0 +1,70 @@
+/*
+     Copyright (c) 2014 Red Hat, Inc. <http://www.redhat.com>
+     This file is part of GlusterFS.
+
+     This file is licensed to you under your choice of the GNU Lesser
+     General Public License, version 3 or any later version (LGPLv3 or
+     later), or the GNU General Public License, version 2 (GPLv2), in all
+     cases as published by the Free Software Foundation.
+*/
+
+#include "changelog-helpers.h"
+#include "call-stub.h"
+
+/* Enqueue a stub*/
+void
+__chlog_barrier_enqueue (xlator_t *this, call_stub_t *stub)
+{
+        changelog_priv_t *priv    = NULL;
+
+        priv = this->private;
+        GF_ASSERT (priv);
+
+        list_add_tail (&stub->list, &priv->queue);
+        priv->queue_size++;
+
+        return;
+}
+
+/* Dequeue a stub */
+call_stub_t *
+__chlog_barrier_dequeue (xlator_t *this, struct list_head *queue)
+{
+        call_stub_t      *stub            = NULL;
+        changelog_priv_t *priv            = NULL;
+
+        priv = this->private;
+        GF_ASSERT (priv);
+
+        if (list_empty (queue))
+                goto out;
+
+        stub = list_entry (queue->next, call_stub_t, list);
+        list_del_init (&stub->list);
+
+out:
+        return stub;
+}
+
+/* Dequeue all the stubs and call corresponding resume functions */
+void
+chlog_barrier_dequeue_all (xlator_t *this, struct list_head *queue)
+{
+        call_stub_t            *stub    = NULL;
+
+        while ((stub = __chlog_barrier_dequeue (this, queue)))
+                call_resume (stub);
+
+        return;
+}
+
+/* Disable changelog barrier enable flag */
+void
+__chlog_barrier_disable (xlator_t *this, struct list_head *queue)
+{
+        changelog_priv_t  *priv   = this->private;
+
+        list_splice_init (&priv->queue, queue);
+        priv->queue_size = 0;
+        priv->barrier_enabled = _gf_false;
+}