lvol: add spdk_lvol_is_degraded

This is mostly a wrapper around spdk_blob_is_degraded(), but it also
performs a NULL check on lvol->blob. Since an lvol without a blob cannot
perform IO, this condition returns true.

The two callers of spdk_blob_is_degraded() in vbdev_lvol.c have been
updated to use spdk_lvol_is_degraded().

Change-Id: I11dc682a26d971c8854aeab280c8199fced358c3
Signed-off-by: Mike Gerdts <mgerdts@nvidia.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/17896
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

include/spdk/lvol.h

@@ -373,6 +373,14 @@ void spdk_lvol_inflate(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void
  */
 void spdk_lvol_decouple_parent(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void *cb_arg);
 
+/**
+ * Determine if an lvol is degraded. A degraded lvol cannot perform IO.
+ *
+ * \param lvol Handle to lvol
+ * \return true if the lvol has no open blob or the lvol's blob is degraded, else false.
+ */
+bool spdk_lvol_is_degraded(const struct spdk_lvol *lvol);
+
 #ifdef __cplusplus
 }
 #endif

lib/lvol/lvol.c

@@ -2197,3 +2197,14 @@ spdk_lvol_get_by_names(const char *lvs_name, const char *lvol_name)
 	pthread_mutex_unlock(&g_lvol_stores_mutex);
 	return NULL;
 }
+
+bool
+spdk_lvol_is_degraded(const struct spdk_lvol *lvol)
+{
+	struct spdk_blob *blob = lvol->blob;
+
+	if (blob == NULL) {
+		return true;
+	}
+	return spdk_blob_is_degraded(blob);
+}

lib/lvol/spdk_lvol.map

@@ -25,6 +25,7 @@
 	spdk_lvol_iter_immediate_clones;
 	spdk_lvol_get_by_uuid;
 	spdk_lvol_get_by_names;
+	spdk_lvol_is_degraded;
 
 	# internal functions
 	spdk_lvol_resize;

module/bdev/lvol/vbdev_lvol.c

@@ -653,7 +653,7 @@ _vbdev_lvol_destroy(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void *c
 	ctx->cb_fn = cb_fn;
 	ctx->cb_arg = cb_arg;
 
-	if (spdk_blob_is_degraded(lvol->blob)) {
+	if (spdk_lvol_is_degraded(lvol)) {
 		spdk_lvol_close(lvol, _vbdev_lvol_destroy_cb, ctx);
 		return;
 	}
@@ -1111,7 +1111,7 @@ _create_lvol_disk(struct spdk_lvol *lvol, bool destroy)
 	unsigned char *alias;
 	int rc;
 
-	if (spdk_blob_is_degraded(lvol->blob)) {
+	if (spdk_lvol_is_degraded(lvol)) {
 		SPDK_NOTICELOG("lvol %s: blob is degraded: deferring bdev creation\n",
 			       lvol->unique_id);
 		return 0;

test/unit/lib/bdev/vbdev_lvol.c/vbdev_lvol_ut.c

@@ -49,8 +49,8 @@ DEFINE_STUB(spdk_lvol_iter_immediate_clones, int,
 DEFINE_STUB(spdk_lvs_esnap_missing_add, int,
 	    (struct spdk_lvol_store *lvs, struct spdk_lvol *lvol, const void *esnap_id,
 	     uint32_t id_len), -ENOTSUP);
-DEFINE_STUB(spdk_blob_is_degraded, bool, (const struct spdk_blob *blob), false);
 DEFINE_STUB(spdk_blob_get_esnap_bs_dev, struct spdk_bs_dev *, (const struct spdk_blob *blob), NULL);
+DEFINE_STUB(spdk_lvol_is_degraded, bool, (const struct spdk_lvol *lvol), false);
 
 struct spdk_blob {
 	uint64_t	id;
@@ -1836,7 +1836,7 @@ ut_esnap_dev_create(void)
 
 	/* Bdev not found */
 	g_base_bdev = NULL;
-	MOCK_SET(spdk_blob_is_degraded, true);
+	MOCK_SET(spdk_lvol_is_degraded, true);
 	rc = vbdev_lvol_esnap_dev_create(&lvs, &lvol, &blob, uuid_str, sizeof(uuid_str), &bs_dev);
 	CU_ASSERT(rc == 0);
 	SPDK_CU_ASSERT_FATAL(bs_dev != NULL);
@@ -1847,7 +1847,7 @@ ut_esnap_dev_create(void)
 	/* TODO: This suggests we need a way to wait for a claim to be available. */
 	g_base_bdev = &bdev;
 	lvol_already_opened = true;
-	MOCK_SET(spdk_blob_is_degraded, true);
+	MOCK_SET(spdk_lvol_is_degraded, true);
 	rc = vbdev_lvol_esnap_dev_create(&lvs, &lvol, &blob, uuid_str, sizeof(uuid_str), &bs_dev);
 	CU_ASSERT(rc == 0);
 	SPDK_CU_ASSERT_FATAL(bs_dev != NULL);
@@ -1856,7 +1856,7 @@ ut_esnap_dev_create(void)
 
 	/* Happy path */
 	lvol_already_opened = false;
-	MOCK_SET(spdk_blob_is_degraded, false);
+	MOCK_SET(spdk_lvol_is_degraded, false);
 	rc = vbdev_lvol_esnap_dev_create(&lvs, &lvol, &blob, uuid_str, sizeof(uuid_str), &bs_dev);
 	CU_ASSERT(rc == 0);
 	SPDK_CU_ASSERT_FATAL(bs_dev != NULL);
@@ -1866,7 +1866,7 @@ ut_esnap_dev_create(void)
 	g_base_bdev = NULL;
 	lvol_already_opened = false;
 	free(unterminated);
-	MOCK_CLEAR(spdk_blob_is_degraded);
+	MOCK_CLEAR(spdk_lvol_is_degraded);
 }
 
 static void

test/unit/lib/lvol/lvol.c/lvol_ut.c

@@ -35,6 +35,7 @@ DEFINE_STUB(spdk_bdev_create_bs_dev_ro, int,
 	    (const char *bdev_name, spdk_bdev_event_cb_t event_cb, void *event_ctx,
 	     struct spdk_bs_dev **bs_dev), -ENOTSUP);
 DEFINE_STUB(spdk_blob_is_esnap_clone, bool, (const struct spdk_blob *blob), false);
+DEFINE_STUB(spdk_blob_is_degraded, bool, (const struct spdk_blob *blob), false);
 
 const char *uuid = "828d9766-ae50-11e7-bd8d-001e67edf350";