Handling of flag(ZVOL_OP_FLAG_READ_METADATA) for reading metadata for…

… read command (openzfs#64)


Signed-off-by: mayank <[email protected]>

cmd/zrepl/data_conn.c

@@ -200,18 +200,22 @@ uzfs_zvol_worker(void *arg)
 	int		rc = 0;
 	int 		write = 0;
 	boolean_t	rebuild_cmd_req;
+	boolean_t	read_metadata;
 
 	zio_cmd = (zvol_io_cmd_t *)arg;
 	hdr = &zio_cmd->hdr;
 	zinfo = zio_cmd->zv;
 	zvol_state = zinfo->zv;
 	rebuild_cmd_req = hdr->flags & ZVOL_OP_FLAG_REBUILD;
+	read_metadata = hdr->flags & ZVOL_OP_FLAG_READ_METADATA;
 
 	/*
 	 * If zvol hasn't passed rebuild phase or if read
-	 * is meant for rebuild then we need the metadata
+	 * is meant for rebuild or if target has asked for metadata
+	 * then we need the metadata
 	 */
-	if (!rebuild_cmd_req && ZVOL_IS_REBUILDED(zvol_state)) {
+	if ((!rebuild_cmd_req && ZVOL_IS_REBUILDED(zvol_state)) &&
+	    !read_metadata) {
 		metadata_desc = NULL;
 		zio_cmd->metadata_desc = NULL;
 	} else {
@@ -361,7 +365,11 @@ uzfs_zvol_rebuild_dw_replica(void *arg)
 		hdr.opcode = ZVOL_OPCODE_REBUILD_STEP;
 		hdr.checkpointed_io_seq = checkpointed_ionum;
 		hdr.offset = offset;
-		hdr.len = ZVOL_REBUILD_STEP_SIZE;
+		if ((offset + ZVOL_REBUILD_STEP_SIZE) >
+		    ZVOL_VOLUME_SIZE(zvol_state))
+			hdr.len = ZVOL_VOLUME_SIZE(zvol_state) - offset;
+		else
+			hdr.len = ZVOL_REBUILD_STEP_SIZE;
 		rc = uzfs_zvol_socket_write(sfd, (char *)&hdr, sizeof (hdr));
 		if (rc != 0) {
 			LOG_ERRNO("Socket write failed");

cmd/zrepl/zrepl.c

@@ -378,8 +378,8 @@ uzfs_zvol_rebuild_scanner(void *arg)
 			    uzfs_zvol_rebuild_scanner_callback,
 			    rebuild_req_offset, rebuild_req_len, &warg);
 			if (rc != 0) {
-				LOG_ERR("Rebuild scanning failed on zvol %s",
-				    zinfo->name);
+				LOG_ERR("Rebuild scanning failed on zvol %s "
+				    "err(%d)", zinfo->name, rc);
 			}
 			bzero(&hdr, sizeof (hdr));
 			hdr.status = ZVOL_OP_STATUS_OK;

include/zrepl_prot.h

@@ -50,7 +50,8 @@ extern "C" {
 #define	MAX_IP_LEN	64
 #define	TARGET_PORT	6060
 
-#define	ZVOL_OP_FLAG_REBUILD 0x01
+#define	ZVOL_OP_FLAG_REBUILD		0x01
+#define	ZVOL_OP_FLAG_READ_METADATA	0x02
 
 enum zvol_op_code {
 	// Used to obtain info about a zvol on mgmt connection

tests/cbtest/gtest/.gitignore

@@ -1,2 +1,3 @@
 /test_uzfs
 /test_zrepl_prot
+/test_zfs

tests/cbtest/gtest/test_zrepl_prot.cc

@@ -198,7 +198,7 @@ static void write_data(int data_fd, int &ioseq, void *buf, size_t offset,
  * left to the caller.
  */
 static void read_data_start(int data_fd, int &ioseq, size_t offset, int len,
-    zvol_io_hdr_t *hdr_inp, bool rebuild_flag=false) {
+    zvol_io_hdr_t *hdr_inp, int flags = 0) {
 	zvol_io_hdr_t hdr_out;
 	int rc;
 
@@ -208,7 +208,7 @@ static void read_data_start(int data_fd, int &ioseq, size_t offset, int len,
 	hdr_out.io_seq = ++ioseq;
 	hdr_out.offset = offset;
 	hdr_out.len = len;
-	hdr_out.flags = (rebuild_flag) ? ZVOL_OP_FLAG_REBUILD : 0;
+	hdr_out.flags = flags;
 
 	rc = write(data_fd, &hdr_out, sizeof (hdr_out));
 	ASSERT_EQ(rc, sizeof (hdr_out));
@@ -974,8 +974,8 @@ TEST_F(ZreplDataTest, WriteInvalidLength) {
 }
 
 /*
- * Metadata ionum should be returned only when zvol is degraded (rebuild
- * not finished) or when explicitly requested by ZVOL_OP_FLAG_REBUILD flag.
+ * Metadata ionum should be returned when zvol is degraded (rebuild
+ * not finished) or when requested by ZVOL_OP_FLAG_REBUILD flag.
  */
 TEST_F(ZreplDataTest, RebuildFlag) {
 	zvol_io_hdr_t hdr_in, hdr_out;
@@ -1000,7 +1000,7 @@ TEST_F(ZreplDataTest, RebuildFlag) {
 	get_zvol_status(m_zvol_name1, m_ioseq1, m_control_fd1, ZVOL_STATUS_HEALTHY, ZVOL_REBUILDING_DONE);
 
 	/* read the block without rebuild flag */
-	read_data_start(m_data_fd1, m_ioseq1, 0, sizeof (buf), &hdr_in, false);
+	read_data_start(m_data_fd1, m_ioseq1, 0, sizeof (buf), &hdr_in, 0);
 	ASSERT_EQ(hdr_in.status, ZVOL_OP_STATUS_OK);
 	ASSERT_EQ(hdr_in.len, sizeof (read_hdr) + sizeof (buf));
 	rc = read(m_data_fd1, &read_hdr, sizeof (read_hdr));
@@ -1013,7 +1013,50 @@ TEST_F(ZreplDataTest, RebuildFlag) {
 	ASSERT_EQ(rc, sizeof (buf));
 
 	/* read the block with rebuild flag */
-	read_data_start(m_data_fd1, m_ioseq1, 0, sizeof (buf), &hdr_in, true);
+	read_data_start(m_data_fd1, m_ioseq1, 0, sizeof (buf), &hdr_in, ZVOL_OP_FLAG_REBUILD);
+	ASSERT_EQ(hdr_in.status, ZVOL_OP_STATUS_OK);
+	ASSERT_EQ(hdr_in.len, sizeof (read_hdr) + sizeof (buf));
+	rc = read(m_data_fd1, &read_hdr, sizeof (read_hdr));
+	ASSERT_ERRNO("read", rc >= 0);
+	ASSERT_EQ(rc, sizeof (read_hdr));
+	ASSERT_EQ(read_hdr.io_num, 654);
+	ASSERT_EQ(read_hdr.len, sizeof (buf));
+	rc = read(m_data_fd1, buf, sizeof (buf));
+	ASSERT_ERRNO("read", rc >= 0);
+	ASSERT_EQ(rc, sizeof (buf));
+}
+
+/*
+ * Metadata ionum should be returned when requested by
+ * ZVOL_OP_FLAG_READ_METADATA flag.
+ */
+TEST_F(ZreplDataTest, ReadMetaDataFlag) {
+	zvol_io_hdr_t hdr_in, hdr_out;
+	struct zvol_io_rw_hdr read_hdr;
+	struct zvol_io_rw_hdr write_hdr;
+	struct zrepl_status_ack status;
+	struct mgmt_ack mgmt_ack;
+	char buf[4096];
+	int rc;
+
+	/* write a data block with known ionum */
+	write_data_and_verify_resp(m_data_fd1, m_ioseq1, 0, 654);
+
+	/* read the block without ZVOL_OP_FLAG_READ_METADATA flag */
+	read_data_start(m_data_fd1, m_ioseq1, 0, sizeof (buf), &hdr_in, 0);
+	ASSERT_EQ(hdr_in.status, ZVOL_OP_STATUS_OK);
+	ASSERT_EQ(hdr_in.len, sizeof (read_hdr) + sizeof (buf));
+	rc = read(m_data_fd1, &read_hdr, sizeof (read_hdr));
+	ASSERT_ERRNO("read", rc >= 0);
+	ASSERT_EQ(rc, sizeof (read_hdr));
+	ASSERT_EQ(read_hdr.io_num, 0);
+	ASSERT_EQ(read_hdr.len, sizeof (buf));
+	rc = read(m_data_fd1, buf, sizeof (buf));
+	ASSERT_ERRNO("read", rc >= 0);
+	ASSERT_EQ(rc, sizeof (buf));
+
+	/* read the block with ZVOL_OP_FLAG_READ_METADATA flag */
+	read_data_start(m_data_fd1, m_ioseq1, 0, sizeof (buf), &hdr_in, ZVOL_OP_FLAG_READ_METADATA);
 	ASSERT_EQ(hdr_in.status, ZVOL_OP_STATUS_OK);
 	ASSERT_EQ(hdr_in.len, sizeof (read_hdr) + sizeof (buf));
 	rc = read(m_data_fd1, &read_hdr, sizeof (read_hdr));