bdev/lvol: add UUID to lvols

In addition to the lvolstore uuid, add a per-lvol uuid for bdev
identification.

The lvol uuid is stored as an xattr for each lvol blob; if an lvol blob
without a uuid xattr is encountered, the lvol bdev will not report a
uuid for now (it will be set to all zeroes, which will be treated as
no uuid available by the generic bdev layer).

Change-Id: If00221383a12d62234fc085d56e257dd48053103
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/402973
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

include/spdk_internal/lvolstore.h

@@ -98,6 +98,8 @@ struct spdk_lvol {
 	spdk_blob_id			blob_id;
 	char				*unique_id;
 	char				name[SPDK_LVOL_NAME_MAX];
+	struct spdk_uuid		uuid;
+	char				uuid_str[SPDK_UUID_STRING_LEN];
 	bool				close_only;
 	bool				thin_provision;
 	struct spdk_bdev		*bdev;

lib/bdev/lvol/vbdev_lvol.c

@@ -749,6 +749,7 @@ _create_lvol_disk(struct spdk_lvol *lvol)
 	total_size = lvol->num_clusters * spdk_bs_get_cluster_size(lvol->lvol_store->blobstore);
 	assert((total_size % bdev->blocklen) == 0);
 	bdev->blockcnt = total_size / bdev->blocklen;
+	bdev->uuid = lvol->uuid;
 
 	bdev->ctxt = lvol;
 	bdev->fn_table = &vbdev_lvol_fn_table;

lib/lvol/lvol.c

@@ -36,6 +36,7 @@
 #include "spdk/string.h"
 #include "spdk/io_channel.h"
 #include "spdk/blob_bdev.h"
+#include "spdk/util.h"
 
 /* Default blob channel opts for lvol */
 #define SPDK_LVOL_BLOB_OPTS_CHANNEL_OPS 512
@@ -213,11 +214,19 @@ _spdk_load_next_lvol(void *cb_arg, struct spdk_blob *blob, int lvolerrno)
 
 	strncpy(lvol->name, attr, SPDK_LVOL_NAME_MAX);
 
+	rc = spdk_blob_get_xattr_value(blob, "uuid", (const void **)&attr, &value_len);
+	if (rc != 0 || value_len != SPDK_UUID_STRING_LEN || attr[SPDK_UUID_STRING_LEN - 1] != '\0' ||
+	    spdk_uuid_parse(&lvol->uuid, attr) != 0) {
+		SPDK_INFOLOG(SPDK_LOG_LVOL, "Missing or corrupt lvol uuid\n");
+		memset(&lvol->uuid, 0, sizeof(lvol->uuid));
+	}
+	spdk_uuid_fmt_lower(lvol->uuid_str, sizeof(lvol->uuid_str), &lvol->uuid);
+
 	TAILQ_INSERT_TAIL(&lvs->lvols, lvol, link);
 
 	lvs->lvol_count++;
 
-	SPDK_INFOLOG(SPDK_LOG_LVOL, "added lvol %s\n", lvol->unique_id);
+	SPDK_INFOLOG(SPDK_LOG_LVOL, "added lvol %s (%s)\n", lvol->unique_id, lvol->uuid_str);
 
 	spdk_bs_iter_next(bs, blob, _spdk_load_next_lvol, req);
 
@@ -904,6 +913,9 @@ spdk_lvol_get_xattr_value(void *xattr_ctx, const char *name,
 	if (!strcmp(LVOL_NAME, name)) {
 		*value = lvol->name;
 		*value_len = SPDK_LVOL_NAME_MAX;
+	} else if (!strcmp("uuid", name)) {
+		*value = lvol->uuid_str;
+		*value_len = sizeof(lvol->uuid_str);
 	}
 }
 
@@ -916,7 +928,7 @@ spdk_lvol_create(struct spdk_lvol_store *lvs, const char *name, uint64_t sz,
 	struct spdk_lvol *lvol, *tmp;
 	struct spdk_blob_opts opts;
 	uint64_t num_clusters;
-	char *xattr_name = LVOL_NAME;
+	char *xattr_names[] = {LVOL_NAME, "uuid"};
 
 	if (lvs == NULL) {
 		SPDK_ERRLOG("lvol store does not exist\n");
@@ -963,13 +975,15 @@ spdk_lvol_create(struct spdk_lvol_store *lvs, const char *name, uint64_t sz,
 	lvol->close_only = false;
 	lvol->thin_provision = thin_provision;
 	strncpy(lvol->name, name, SPDK_LVS_NAME_MAX);
+	spdk_uuid_generate(&lvol->uuid);
+	spdk_uuid_fmt_lower(lvol->uuid_str, sizeof(lvol->uuid_str), &lvol->uuid);
 	req->lvol = lvol;
 
 	spdk_blob_opts_init(&opts);
 	opts.thin_provision = thin_provision;
 	opts.num_clusters = num_clusters;
-	opts.xattrs.count = 1;
+	opts.xattrs.count = SPDK_COUNTOF(xattr_names);
-	opts.xattrs.names = &xattr_name;
+	opts.xattrs.names = xattr_names;
 	opts.xattrs.ctx = lvol;
 	opts.xattrs.get_value = spdk_lvol_get_xattr_value;