HBASE-28405 Fix failed procedure rollback when region was not closed …

…and is still in state merging (#5799)

Co-authored-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
(cherry picked from commit ba09913)

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/MergeTableRegionsProcedure.java

@@ -288,6 +288,7 @@ protected void rollbackState(final MasterProcedureEnv env, final MergeTableRegio
           postRollBackMergeRegions(env);
           break;
         case MERGE_TABLE_REGIONS_PREPARE:
+          rollbackPrepareMerge(env);
           break;
         default:
           throw new UnsupportedOperationException(this + " unhandled state=" + state);
@@ -513,6 +514,19 @@ private boolean isMergeable(final MasterProcedureEnv env, final RegionState rs)
     return response.hasMergeable() && response.getMergeable();
   }
 
+  /**
+   * Action for rollback a merge table after prepare merge
+   */
+  private void rollbackPrepareMerge(final MasterProcedureEnv env) throws IOException {
+    for (RegionInfo rinfo : regionsToMerge) {
+      RegionStateNode regionStateNode =
+        env.getAssignmentManager().getRegionStates().getRegionStateNode(rinfo);
+      if (regionStateNode.getState() == State.MERGING) {
+        regionStateNode.setState(State.OPEN);
+      }
+    }
+  }
+
   /**
    * Pre merge region action
    * @param env MasterProcedureEnv
@@ -633,8 +647,20 @@ private void cleanupMergedRegion(final MasterProcedureEnv env) throws IOExceptio
    * Rollback close regions
    **/
   private void rollbackCloseRegionsForMerge(MasterProcedureEnv env) throws IOException {
-    AssignmentManagerUtil.reopenRegionsForRollback(env, Arrays.asList(regionsToMerge),
-      getRegionReplication(env), getServerName(env));
+    // At this point we should check if region was actually closed. If it was not closed then we
+    // don't need to repoen the region and we can just change the regionNode state to OPEN.
+    // if it is alredy closed then we need to do a reopen of region
+    List<RegionInfo> toAssign = new ArrayList<>();
+    for (RegionInfo rinfo : regionsToMerge) {
+      RegionStateNode regionStateNode =
+        env.getAssignmentManager().getRegionStates().getRegionStateNode(rinfo);
+      if (regionStateNode.getState() != State.MERGING) {
+        // same as before HBASE-28405
+        toAssign.add(rinfo);
+      }
+    }
+    AssignmentManagerUtil.reopenRegionsForRollback(env, toAssign, getRegionReplication(env),
+      getServerName(env));
   }
 
   private TransitRegionStateProcedure[] createUnassignProcedures(MasterProcedureEnv env)

hbase-server/src/test/java/org/apache/hadoop/hbase/namespace/TestNamespaceAuditor.java

@@ -37,6 +37,7 @@
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.Coprocessor;
 import org.apache.hadoop.hbase.CoprocessorEnvironment;
+import org.apache.hadoop.hbase.DoNotRetryIOException;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.HColumnDescriptor;
@@ -52,7 +53,6 @@
 import org.apache.hadoop.hbase.client.CompactionState;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.ConnectionFactory;
-import org.apache.hadoop.hbase.client.DoNotRetryRegionException;
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.RegionLocator;
 import org.apache.hadoop.hbase.client.Table;
@@ -405,7 +405,7 @@ public boolean evaluate() throws Exception {
     try {
       ADMIN.split(tableTwo, Bytes.toBytes("6"));
       fail();
-    } catch (DoNotRetryRegionException e) {
+    } catch (DoNotRetryIOException e) {
       // Expected
     }
     Thread.sleep(2000);