Merge pull request #6962 from liewegas/wip-buffer-lastp

buffer: fix internal iterator invalidation on rebuild, get_contiguous Reviewed-by: Samuel Just <sjust@redhat.com>
ceph · Dec 31, 2015 · d5b9767 · d5b9767
2 parents b5a2a76 + b88561a
commit d5b9767
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diff --git a/src/common/buffer.cc b/src/common/buffer.cc
@@ -1402,6 +1402,7 @@ static simple_spinlock_t buffer_debug_lock = SIMPLE_SPINLOCK_INITIALIZER;
     if (nb.length())
       _buffers.push_back(nb);
     invalidate_crc();
+    last_p = begin();
   }
 
   void buffer::list::rebuild_aligned(unsigned align)
@@ -1449,6 +1450,7 @@ static simple_spinlock_t buffer_debug_lock = SIMPLE_SPINLOCK_INITIALIZER;
       }
       _buffers.insert(p, unaligned._buffers.front());
     }
+    last_p = begin();
   }
 
   void buffer::list::rebuild_page_aligned()
@@ -1693,6 +1695,8 @@ static simple_spinlock_t buffer_debug_lock = SIMPLE_SPINLOCK_INITIALIZER;
       return tmp.c_str() + off;
     }
 
+    last_p = begin();  // we modified _buffers
+
     return curbuf->c_str() + off;
   }
 

diff --git a/src/test/bufferlist.cc b/src/test/bufferlist.cc
@@ -876,6 +876,17 @@ TEST(BufferListIterator, constructors) {
   }
 }
 
+TEST(BufferListIterator, empty_create_append_copy) {
+  bufferlist bl, bl2, bl3, out;
+  bl2.append("bar");
+  bl.swap(bl2);
+  bl2.append("xxx");
+  bl.append(bl2);
+  bl.rebuild();
+  bl.copy(0, 6, out);
+  ASSERT_TRUE(out.contents_equal(bl));
+}
+
 TEST(BufferListIterator, operator_equal) {
   bufferlist bl;
   bl.append("ABC", 3);