HBASE-25206 Data loss can happen if a cloned table loses original split region(delete table) (#2569)

Signed-off-by: Duo Zhang <zhangduo@apache.org>

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

@@ -362,6 +362,18 @@ public class RegionStates {
       regionNode -> !regionNode.isInState(State.SPLIT) && !regionNode.getRegionInfo().isSplit());
   }
 
+  /**
+   * Get the regions for deleting a table.
+   * <p/>
+   * Here we need to return all the regions irrespective of the states in order to archive them
+   * all. This is because if we don't archive OFFLINE/SPLIT regions and if a snapshot or a cloned
+   * table references to the regions, we will lose the data of the regions.
+   */
+  public List<RegionInfo> getRegionsOfTableForDeleting(TableName table) {
+    return getTableRegionStateNodes(table).stream().map(RegionStateNode::getRegionInfo)
+      .collect(Collectors.toList());
+  }
+
   /**
    * @return Return the regions of the table and filter them.
    */

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

@@ -348,6 +348,7 @@ public class TransitRegionStateProcedure
               LOG.error(
                 "Cannot assign replica region {} because its primary region {} does not exist.",
                 regionNode.getRegionInfo(), defaultRI);
+              regionNode.unsetProcedure(this);
               return Flow.NO_MORE_STATE;
             }
           }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DeleteTableProcedure.java

@@ -99,7 +99,8 @@ public class DeleteTableProcedure
 
           // TODO: Move out... in the acquireLock()
           LOG.debug("Waiting for RIT for {}", this);
-          regions = env.getAssignmentManager().getRegionStates().getRegionsOfTable(getTableName());
+          regions = env.getAssignmentManager().getRegionStates()
+            .getRegionsOfTableForDeleting(getTableName());
           assert regions != null && !regions.isEmpty() : "unexpected 0 regions";
           ProcedureSyncWait.waitRegionInTransition(env, regions);
 

hbase-server/src/test/java/org/apache/hadoop/hbase/client/CloneSnapshotFromClientAfterSplittingRegionTestBase.java

@@ -80,4 +80,40 @@ public class CloneSnapshotFromClientAfterSplittingRegionTestBase
       admin.catalogJanitorSwitch(true);
     }
   }
+
+  @Test
+  public void testCloneSnapshotBeforeSplittingRegionAndDroppingTable()
+    throws IOException, InterruptedException {
+    // Turn off the CatalogJanitor
+    admin.catalogJanitorSwitch(false);
+
+    try {
+      // Take a snapshot
+      admin.snapshot(snapshotName2, tableName);
+
+      // Clone the snapshot to another table
+      TableName clonedTableName =
+        TableName.valueOf(getValidMethodName() + "-" + System.currentTimeMillis());
+      admin.cloneSnapshot(snapshotName2, clonedTableName);
+      SnapshotTestingUtils.waitForTableToBeOnline(TEST_UTIL, clonedTableName);
+
+      // Split the first region of the original table
+      List<RegionInfo> regionInfos = admin.getRegions(tableName);
+      RegionReplicaUtil.removeNonDefaultRegions(regionInfos);
+      splitRegion(regionInfos.get(0));
+
+      // Drop the original table
+      admin.disableTable(tableName);
+      admin.deleteTable(tableName);
+
+      // Disable and enable the cloned table. This should be successful
+      admin.disableTable(clonedTableName);
+      admin.enableTable(clonedTableName);
+      SnapshotTestingUtils.waitForTableToBeOnline(TEST_UTIL, clonedTableName);
+
+      verifyRowCount(TEST_UTIL, clonedTableName, snapshot1Rows);
+    } finally {
+      admin.catalogJanitorSwitch(true);
+    }
+  }
 }