gluster: GlusterFS Volume Snapshot Feature

This is the initial patch for the Snapshot feature. Current patch
includes following features:
* Snapshot create
* Snapshot delete
* Snapshot restore
* Snapshot list
* Snapshot info
* Snapshot status
* Snapshot config

Change-Id: I2f46920c0d61c515f6a60e0f8b46fff886d9f6a9
BUG: 1061685
Signed-off-by: shishir gowda <sgowda@redhat.com>
Signed-off-by: Sachin Pandit <spandit@redhat.com>
Signed-off-by: Vijaikumar M <vmallika@redhat.com>
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>
Signed-off-by: Rajesh Joseph <rjoseph@redhat.com>
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/7128
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/libglusterfs/src/list.h b/libglusterfs/src/list.h
index 794586e35f6..04b4047129f 100644
--- a/libglusterfs/src/list.h
+++ b/libglusterfs/src/list.h
@@ -45,19 +45,29 @@ list_add_tail (struct list_head *new, struct list_head *head)
 }
 
 
+/* This function will insert the element to the list in a order.
+   Order will be based on the compare function provided as a input.
+   If element to be inserted in ascending order compare should return:
+    0: if both the arguments are equal
+   >0: if first argument is greater than second argument
+   <0: if first argument is less than second argument */
 static inline void
 list_add_order (struct list_head *new, struct list_head *head,
                 int (*compare)(struct list_head *, struct list_head *))
 {
-        struct list_head *pos = head->next;
+        struct list_head *pos = head->prev;
 
         while ( pos != head ) {
-                if (compare(new, pos) <= 0)
+                if (compare(new, pos) >= 0)
                         break;
-                pos = pos->next;
+
+                /* Iterate the list in the reverse order. This will have
+                   better efficiency if the elements are inserted in the
+                   ascending order */
+                pos = pos->prev;
         }
 
-        list_add_tail(new, pos);
+        list_add (new, pos);
 }
 
 static inline void