librbd: avoid canceling object map / header updates

During a resize, reduce the possibility that the object map and the header will get out-of-sync during a resize operation that is canceled. Signed-off-by: Jason Dillaman <[email protected]>
amincheloh · Mar 10, 2015 · 7f246b8 · 7f246b8
1 parent 85737ab
commit 7f246b8
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Showing 3 changed files with 22 additions and 1 deletion.
diff --git a/src/librbd/AsyncRequest.h b/src/librbd/AsyncRequest.h
@@ -19,7 +19,7 @@ class AsyncRequest
   virtual ~AsyncRequest();
 
   void complete(int r) {
-    if (m_canceled) {
+    if (m_canceled && safely_cancel(r)) {
       m_on_finish->complete(-ERESTART);
       delete this;
     } else if (should_complete(r)) {
@@ -44,6 +44,9 @@ class AsyncRequest
   librados::AioCompletion *create_callback_completion();
   Context *create_callback_context();
 
+  virtual bool safely_cancel(int r) {
+    return true;
+  }
   virtual bool should_complete(int r) = 0;
 
 private:

diff --git a/src/librbd/AsyncResizeRequest.cc b/src/librbd/AsyncResizeRequest.cc
@@ -46,6 +46,23 @@ AsyncResizeRequest::~AsyncResizeRequest() {
   }
 }
 
+bool AsyncResizeRequest::safely_cancel(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 5) << this << " safely_cancel: " << " r=" << r << dendl;
+
+  // avoid interrupting the object map / header updates
+  switch (m_state) {
+  case STATE_GROW_OBJECT_MAP:
+  case STATE_UPDATE_HEADER:
+  case STATE_SHRINK_OBJECT_MAP:
+    ldout(cct, 5) << "delaying cancel request" << dendl;
+    return false;
+  default:
+    break;
+  }
+  return true;
+}
+
 bool AsyncResizeRequest::should_complete(int r) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 5) << this << " should_complete: " << " r=" << r << dendl;

diff --git a/src/librbd/AsyncResizeRequest.h b/src/librbd/AsyncResizeRequest.h
@@ -83,6 +83,7 @@ class AsyncResizeRequest : public AsyncRequest
 
   xlist<AsyncResizeRequest *>::item m_xlist_item;
 
+  virtual bool safely_cancel(int r);
   virtual bool should_complete(int r);
 
   void send_flush();