From e7155b3d595317f193d2493f1ae627ef5fb9f7c3 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Thu, 29 Sep 2016 10:21:32 -0400
Subject: [PATCH] buffer: make iterator copy to ptr handle len==0

Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/common/buffer.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/common/buffer.cc b/src/common/buffer.cc
index 74a84a3b8cf7..91b240fad737 100644
--- a/src/common/buffer.cc
+++ b/src/common/buffer.cc
@@ -1163,6 +1163,9 @@ static simple_spinlock_t buffer_debug_lock = SIMPLE_SPINLOCK_INITIALIZER;
   template<bool is_const>
   void buffer::list::iterator_impl<is_const>::copy_deep(unsigned len, ptr &dest)
   {
+    if (!len) {
+      return;
+    }
     if (p == ls->end())
       throw end_of_buffer();
     assert(p->length() > 0);
@@ -1173,6 +1176,9 @@ static simple_spinlock_t buffer_debug_lock = SIMPLE_SPINLOCK_INITIALIZER;
   void buffer::list::iterator_impl<is_const>::copy_shallow(unsigned len,
 							   ptr &dest)
   {
+    if (!len) {
+      return;
+    }
     if (p == ls->end())
       throw end_of_buffer();
     assert(p->length() > 0);
-- 
2.47.3