HDFS-9057. allow/disallow snapshots via webhdfs (Contributed by Brahma Reddy Battula)

(cherry picked from commit 6d2332ae37)
(cherry picked from commit 4b21b47f56)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -1227,6 +1227,12 @@ public class WebHdfsFileSystem extends FileSystem
     new FsPathRunner(op, p, new AclPermissionParam(aclSpec)).run();
   }
 
+  public void allowSnapshot(final Path p) throws IOException {
+    statistics.incrementWriteOps(1);
+    final HttpOpParam.Op op = PutOpParam.Op.ALLOWSNAPSHOT;
+    new FsPathRunner(op, p).run();
+  }
+
   @Override
   public Path createSnapshot(final Path path, final String snapshotName)
       throws IOException {
@@ -1242,6 +1248,12 @@ public class WebHdfsFileSystem extends FileSystem
     }.run();
   }
 
+  public void disallowSnapshot(final Path p) throws IOException {
+    statistics.incrementWriteOps(1);
+    final HttpOpParam.Op op = PutOpParam.Op.DISALLOWSNAPSHOT;
+    new FsPathRunner(op, p).run();
+  }
+
   @Override
   public void deleteSnapshot(final Path path, final String snapshotName)
       throws IOException {

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/web/resources/PutOpParam.java

@@ -46,6 +46,8 @@ public class PutOpParam extends HttpOpParam<PutOpParam.Op> {
     SETXATTR(false, HttpURLConnection.HTTP_OK),
     REMOVEXATTR(false, HttpURLConnection.HTTP_OK),
 
+    ALLOWSNAPSHOT(false, HttpURLConnection.HTTP_OK),
+    DISALLOWSNAPSHOT(false, HttpURLConnection.HTTP_OK),
     CREATESNAPSHOT(false, HttpURLConnection.HTTP_OK),
     RENAMESNAPSHOT(false, HttpURLConnection.HTTP_OK),
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/web/resources/NamenodeWebHdfsMethods.java

@@ -633,6 +633,10 @@ public class NamenodeWebHdfsMethods {
       np.removeXAttr(fullpath, XAttrHelper.buildXAttr(xattrName.getXAttrName()));
       return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
     }
+    case ALLOWSNAPSHOT: {
+      np.allowSnapshot(fullpath);
+      return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
+    }
     case CREATESNAPSHOT: {
       String snapshotPath = np.createSnapshot(fullpath, snapshotName.getValue());
       final String js = JsonUtil.toJsonString(
@@ -644,6 +648,10 @@ public class NamenodeWebHdfsMethods {
           snapshotName.getValue());
       return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
     }
+    case DISALLOWSNAPSHOT: {
+      np.disallowSnapshot(fullpath);
+      return Response.ok().type(MediaType.APPLICATION_OCTET_STREAM).build();
+    }
     default:
       throw new UnsupportedOperationException(op + " is not supported");
     }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/web/TestWebHDFS.java

@@ -61,6 +61,7 @@ import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.TestDFSClientRetries;
 import org.apache.hadoop.hdfs.TestFileCreation;
 import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys;
+import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotTestHelper;
 import org.apache.hadoop.hdfs.server.namenode.web.resources.NamenodeWebHdfsMethods;
@@ -375,6 +376,60 @@ public class TestWebHDFS {
         false));
   }
 
+  /**
+   * Test allow and disallow snapshot through WebHdfs. Verifying webhdfs with
+   * Distributed filesystem methods.
+   */
+  @Test
+  public void testWebHdfsAllowandDisallowSnapshots() throws Exception {
+    MiniDFSCluster cluster = null;
+    final Configuration conf = WebHdfsTestUtil.createConf();
+    try {
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0).build();
+      cluster.waitActive();
+      final DistributedFileSystem dfs = cluster.getFileSystem();
+      final WebHdfsFileSystem webHdfs = WebHdfsTestUtil
+          .getWebHdfsFileSystem(conf, WebHdfsConstants.WEBHDFS_SCHEME);
+
+      final Path bar = new Path("/bar");
+      dfs.mkdirs(bar);
+
+      // allow snapshots on /bar using webhdfs
+      webHdfs.allowSnapshot(bar);
+      webHdfs.createSnapshot(bar, "s1");
+      final Path s1path = SnapshotTestHelper.getSnapshotRoot(bar, "s1");
+      Assert.assertTrue(webHdfs.exists(s1path));
+      SnapshottableDirectoryStatus[] snapshottableDirs =
+          dfs.getSnapshottableDirListing();
+      assertEquals(1, snapshottableDirs.length);
+      assertEquals(bar, snapshottableDirs[0].getFullPath());
+      dfs.deleteSnapshot(bar, "s1");
+      dfs.disallowSnapshot(bar);
+      snapshottableDirs = dfs.getSnapshottableDirListing();
+      assertNull(snapshottableDirs);
+
+      // disallow snapshots on /bar using webhdfs
+      dfs.allowSnapshot(bar);
+      snapshottableDirs = dfs.getSnapshottableDirListing();
+      assertEquals(1, snapshottableDirs.length);
+      assertEquals(bar, snapshottableDirs[0].getFullPath());
+      webHdfs.disallowSnapshot(bar);
+      snapshottableDirs = dfs.getSnapshottableDirListing();
+      assertNull(snapshottableDirs);
+      try {
+        webHdfs.createSnapshot(bar);
+        fail("Cannot create snapshot on a non-snapshottable directory");
+      } catch (Exception e) {
+        GenericTestUtils.assertExceptionContains(
+            "Directory is not a snapshottable directory", e);
+      }
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
+
   /**
    * Test snapshot creation through WebHdfs
    */