libtcmu: add support for write protect

Signed-off-by: liulanzheng <lanzheng.liulz@alibaba-inc.com>

libtcmu.c

@@ -1021,6 +1021,16 @@ bool tcmu_dev_get_unmap_enabled(struct tcmu_device *dev)
 	return dev->unmap_enabled;
 }
 
+void tcmu_dev_set_write_protect_enabled(struct tcmu_device *dev, bool enabled)
+{
+	dev->write_protect_enabled = enabled;
+}
+
+bool tcmu_dev_get_write_protect_enabled(struct tcmu_device *dev)
+{
+	return dev->write_protect_enabled;
+}
+
 int tcmu_dev_get_fd(struct tcmu_device *dev)
 {
 	return dev->fd;
@@ -1060,7 +1070,7 @@ tcmu_dev_get_memory_info(struct tcmu_device *dev, void **base,
 			/* get length of map from file */
 			ssize_t size;
 			char *size_name;
-			
+
 			if (asprintf(&size_name, sizefmt, dev->dev_name) == -1) {
 				tcmu_err("cannot construct device map size filename\n");
 				goto err_free;

libtcmu_common.h

@@ -138,6 +138,8 @@ void tcmu_dev_set_solid_state_media(struct tcmu_device *dev, bool solid_state);
 bool tcmu_dev_get_solid_state_media(struct tcmu_device *dev);
 void tcmu_dev_set_unmap_enabled(struct tcmu_device *dev, bool enabled);
 bool tcmu_dev_get_unmap_enabled(struct tcmu_device *dev);
+void tcmu_dev_set_write_protect_enabled(struct tcmu_device *dev, bool enabled);
+bool tcmu_dev_get_write_protect_enabled(struct tcmu_device *dev);
 struct tcmulib_handler *tcmu_dev_get_handler(struct tcmu_device *dev);
 void tcmu_dev_flush_ring(struct tcmu_device *dev);
 bool tcmu_dev_oooc_supported(struct tcmu_device* dev);

libtcmu_priv.h

@@ -55,6 +55,7 @@ struct tcmu_device {
 	unsigned int write_cache_enabled:1;
 	unsigned int solid_state_media:1;
 	unsigned int unmap_enabled:1;
+	unsigned int write_protect_enabled:1;
 
 	char dev_name[16]; /* e.g. "uio14" */
 	char tcm_hba_name[16]; /* e.g. "user_8" */

scsi.c

@@ -800,6 +800,14 @@ int tcmu_emulate_mode_sense(
 		orig_buf[0] = used_len - 1;
 	}
 
+	if (tcmu_dev_get_write_protect_enabled(dev)) {
+		if (sense_ten) {
+			orig_buf[3] |= 0x80;
+		} else {
+			orig_buf[2] |= 0x80;
+		}
+	}
+
 	tcmu_memcpy_into_iovec(iovec, iov_cnt, orig_buf, alloc_len);
 	free(orig_buf);
 	return TCMU_STS_OK;