dm vdo: add geometry block initialization to encodings.c

Add vdo_initialize_volume_geometry() to populate the geometry block,
computing the space required for the two main regions on disk.

Add uds_compute_index_size() to calculate the space required for the
UDS indexer from the UDS configuration.

Signed-off-by: Bruce Johnston <bjohnsto@redhat.com>
Reviewed-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Author: bjohnsto

drivers/md/dm-vdo/encodings.c

@@ -12,6 +12,7 @@
 #include "permassert.h"
 
 #include "constants.h"
+#include "indexer.h"
 #include "status-codes.h"
 #include "types.h"
 
@@ -1486,3 +1487,71 @@ int vdo_decode_super_block(u8 *buffer)
 
 	return ((checksum != saved_checksum) ? VDO_CHECKSUM_MISMATCH : VDO_SUCCESS);
 }
+
+/**
+ * vdo_compute_index_blocks() - Compute the number of blocks that the indexer will use.
+ * @config: The index config from which the blocks are calculated.
+ * @index_blocks_ptr: The number of blocks the index will use.
+ *
+ * Return: VDO_SUCCESS or an error code.
+ */
+static int vdo_compute_index_blocks(const struct index_config *config,
+				    block_count_t *index_blocks_ptr)
+{
+	int result;
+	u64 index_bytes;
+	struct uds_parameters uds_parameters = {
+		.memory_size = config->mem,
+		.sparse = config->sparse,
+	};
+
+	result = uds_compute_index_size(&uds_parameters, &index_bytes);
+	if (result != UDS_SUCCESS)
+		return vdo_log_error_strerror(result, "error computing index size");
+
+	*index_blocks_ptr = index_bytes / VDO_BLOCK_SIZE;
+	return VDO_SUCCESS;
+}
+
+/**
+ * vdo_initialize_volume_geometry() - Initialize the volume geometry so it can be written out.
+ * @nonce: The nonce to use to identify the vdo.
+ * @uuid: The uuid to use to identify the vdo.
+ * @index_config: The config used for structure initialization.
+ * @geometry: The volume geometry to initialize.
+ *
+ * Return: VDO_SUCCESS or an error code.
+ */
+int vdo_initialize_volume_geometry(nonce_t nonce, uuid_t *uuid,
+				   const struct index_config *index_config,
+				   struct volume_geometry *geometry)
+{
+	int result;
+	block_count_t index_blocks = 0;
+
+	result = vdo_compute_index_blocks(index_config, &index_blocks);
+	if (result != VDO_SUCCESS)
+		return result;
+
+	*geometry = (struct volume_geometry) {
+		/* This is for backwards compatibility. */
+		.unused = 0,
+		.nonce = nonce,
+		.bio_offset = 0,
+		.regions = {
+			[VDO_INDEX_REGION] = {
+				.id = VDO_INDEX_REGION,
+				.start_block = 1,
+			},
+			[VDO_DATA_REGION] = {
+				.id = VDO_DATA_REGION,
+				.start_block = 1 + index_blocks,
+			}
+		}
+	};
+
+	memcpy(&(geometry->uuid), uuid, sizeof(uuid_t));
+	memcpy(&geometry->index_config, index_config, sizeof(struct index_config));
+
+	return VDO_SUCCESS;
+}

drivers/md/dm-vdo/encodings.h

@@ -803,6 +803,10 @@ vdo_get_index_region_size(struct volume_geometry geometry)
 		vdo_get_index_region_start(geometry);
 }
 
+int vdo_initialize_volume_geometry(nonce_t nonce, uuid_t *uuid,
+				   const struct index_config *index_config,
+				   struct volume_geometry *geometry);
+
 int __must_check vdo_parse_geometry_block(unsigned char *block,
 					  struct volume_geometry *geometry);
 

drivers/md/dm-vdo/indexer/index-layout.c

@@ -249,6 +249,32 @@ static int __must_check compute_sizes(const struct uds_configuration *config,
 	return UDS_SUCCESS;
 }
 
+int uds_compute_index_size(const struct uds_parameters *parameters, u64 *index_size)
+{
+	int result;
+	struct uds_configuration *index_config;
+	struct save_layout_sizes sizes;
+
+	if (index_size == NULL) {
+		vdo_log_error("Missing output size pointer");
+		return -EINVAL;
+	}
+
+	result = uds_make_configuration(parameters, &index_config);
+	if (result != UDS_SUCCESS) {
+		vdo_log_error_strerror(result, "cannot compute index size");
+		return result;
+	}
+
+	result = compute_sizes(index_config, &sizes);
+	uds_free_configuration(index_config);
+	if (result != UDS_SUCCESS)
+		return result;
+
+	*index_size = sizes.total_size;
+	return UDS_SUCCESS;
+}
+
 /* Create unique data using the current time and a pseudorandom number. */
 static void create_unique_nonce_data(u8 *buffer)
 {

drivers/md/dm-vdo/indexer/indexer.h

@@ -282,6 +282,10 @@ struct uds_request {
 		     );
 };
 
+/* Compute the number of bytes needed to store an index. */
+int __must_check uds_compute_index_size(const struct uds_parameters *parameters,
+					u64 *index_size);
+
 /* A session is required for most index operations. */
 int __must_check uds_create_index_session(struct uds_index_session **session);