F #6029: Prevent backup removal VM is in BACKUP

Some backup drivers may not allow delete (forget) operations while an
active backup is being performed. This commits fails the
one.image.delete API call in that case.

A new configuration attribute to describe the related driver behavior has been
added CONCURRENT_FORGET for DS_MAD_CONF.

include/Datastore.h

@@ -240,11 +240,16 @@ public:
     };
 
     /**
-     * Returns true if the DS_MAD_CONF has PERSISTENT_ONLY = "YES" flag
-     * @return true if persistent only
+     * @return true if the DS_MAD_CONF has PERSISTENT_ONLY = "YES" flag
      */
     bool is_persistent_only() const;
 
+    /**
+     * (only relevant for backup datastores)
+     * @return true if the DS_MAD_CONF has CONCURRENT_FORGET = "YES" flag
+     */
+    bool is_concurrent_forget() const;
+
     /**
      * Enable or disable the DS. Only for System DS.
      * @param enable true to enable

src/datastore/Datastore.cc

@@ -1110,35 +1110,55 @@ bool Datastore::get_avail_mb(long long &avail) const
 /* ------------------------------------------------------------------------ */
 /* ------------------------------------------------------------------------ */
 
-bool Datastore::is_persistent_only() const
+template <typename T>
+static T ds_conf_value(const string& mad, const string& name, const T& defval)
 {
-    int rc;
-    bool persistent_only = false;
-
     const VectorAttribute* vatt;
 
-    rc = Nebula::instance().get_ds_conf_attribute(ds_mad, vatt);
+    int rc = Nebula::instance().get_ds_conf_attribute(mad, vatt);
 
     if ( rc != 0 )
     {
         // No DS_MAD_CONF is available for this DS_MAD.
-        // Assuming this DS is not PERSISTENT_ONLY
-        return false;
+        return defval;
     }
 
-    vatt->vector_value("PERSISTENT_ONLY", persistent_only);
+    T value;
 
-    return persistent_only;
-};
+    rc = vatt->vector_value(name, value);
 
-/* ------------------------------------------------------------------------ */
-/* ------------------------------------------------------------------------ */
+    if ( rc != 0 )
+    {
+        // Attribute missing in DS_MAD_CONF
+        return defval;
+    }
+
+    return value;
+}
+
+/* -------------------------------------------------------------------------- */
+
+bool Datastore::is_persistent_only() const
+{
+    return ds_conf_value(ds_mad, "PERSISTENT_ONLY", false);
+}
+
+bool Datastore::is_concurrent_forget() const
+{
+    return ds_conf_value(ds_mad, "CONCURRENT_FORGET", false);
+}
+
+/* -------------------------------------------------------------------------- */
+/* -------------------------------------------------------------------------- */
 
 int Datastore::get_tm_mad_targets(const string &tm_mad, string& ln_target,
         string& clone_target, string& disk_type) const
 {
-    if (!tm_mad.empty())
+    if (tm_mad.empty())
     {
+        return 0;
+    }
+
     string tm_mad_t = one_util::trim(tm_mad);
     one_util::toupper(tm_mad_t);
 
@@ -1162,7 +1182,6 @@ int Datastore::get_tm_mad_targets(const string &tm_mad, string& ln_target,
     {
         return -1;
     }
-    }
 
     return 0;
 }

src/image/ImageManagerActions.cc

@@ -462,6 +462,8 @@ int ImageManager::delete_image(int iid, string& error_str)
     int cloning_id = -1;
     int vm_saving_id = -1;
 
+    bool cforget;
+
     ostringstream oss;
 
     if (auto img = ipool->get_ro(iid))
@@ -479,6 +481,8 @@ int ImageManager::delete_image(int iid, string& error_str)
         ds->decrypt();
 
         ds->to_xml(ds_data);
+
+        cforget = ds->is_concurrent_forget();
     }
     else
     {
@@ -494,6 +498,34 @@ int ImageManager::delete_image(int iid, string& error_str)
         return -1;
     }
 
+    // Check associted VM state for backups. Note VM can no longer exist
+    // Fai if VM is in BACKUP and INCREMENT mode or FULL with no CONCURRENT_FORGET
+    if ( img->get_type() == Image::BACKUP )
+    {
+        auto ids   = img->get_running_ids();
+        auto first = ids.cbegin();
+
+        if (first != ids.cend())
+        {
+            VirtualMachinePool* vmpool = Nebula::instance().get_vmpool();
+
+            if (auto vm = vmpool->get_ro(*first))
+            {
+                auto lstate = vm->get_lcm_state();
+                auto bmode  = vm->backups().mode();
+
+                if ((lstate == VirtualMachine::BACKUP ||
+                        lstate == VirtualMachine::BACKUP_POWEROFF) &&
+                        (bmode == Backups::INCREMENT || !cforget))
+                {
+                    error_str = "Active backup on the associated VM. Wait till "
+                        "it finish to delete the backup Image";
+                    return -1;
+                }
+            }
+        }
+    }
+
     switch (img->get_state())
     {
         case Image::READY: