From fda5e1e31d7aa96d87e8efdd2e41b11d52d6f6b1 Mon Sep 17 00:00:00 2001
From: Tiago Castro <tiagolobocastro@gmail.com>
Date: Tue, 12 Dec 2023 19:40:21 +0000
Subject: [PATCH] blobstore: export allocated cluster bitmap for a blob

Signed-off-by: Tiago Castro <tiagolobocastro@gmail.com>
---
 include/spdk/blob.h  | 12 ++++++++++++
 lib/blob/blobstore.c | 25 +++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/include/spdk/blob.h b/include/spdk/blob.h
index ef321131c31..e1b50b9b9f5 100644
--- a/include/spdk/blob.h
+++ b/include/spdk/blob.h
@@ -1180,6 +1180,18 @@ bool spdk_blob_is_degraded(const struct spdk_blob *blob);
  */
 void spdk_blob_reset_used_clusters_cache(struct spdk_blob *blob);
 
+/**
+ * Get the allocated cluster bitmap of the given blob.
+ * This functions takes the blob->bs->used_lock spinlock.
+ *
+ * \param blob The blob to retrieve allocated bitmap from.
+ *
+ * \return NULL if no memory available, otherwise returns a bitmap where each bit corresponds
+ * to a cluster. A set bit indicates the cluster is owned by the blob.
+ * Must be freed using spdk_bit_array_free.
+ */
+struct spdk_bit_array *spdk_blob_get_cluster_bitmap(struct spdk_blob *blob);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/blob/blobstore.c b/lib/blob/blobstore.c
index 46145de7bbc..df82026b82e 100644
--- a/lib/blob/blobstore.c
+++ b/lib/blob/blobstore.c
@@ -5985,6 +5985,31 @@ spdk_blob_reset_used_clusters_cache(struct spdk_blob *blob)
 		spdk_spin_unlock(&blob->bs->used_lock);
 	}
 }
+
+struct spdk_bit_array *
+spdk_blob_get_cluster_bitmap(struct spdk_blob *blob)
+{
+	struct spdk_bit_array *allocated_bitmap;
+	uint64_t i;
+
+	spdk_spin_lock(&blob->bs->used_lock);
+	allocated_bitmap = spdk_bit_array_create(blob->active.num_clusters);
+	if (allocated_bitmap == NULL) {
+		SPDK_ERRLOG("Failed to allocate bit array memory for blob #%ld", blob->id);
+		spdk_spin_unlock(&blob->bs->used_lock);
+		return NULL;
+	}
+
+	for (i = 0; i < blob->active.num_clusters; i++) {
+		if (blob->active.clusters[i]) {
+			spdk_bit_array_set(allocated_bitmap, i);
+		}
+	}
+
+	spdk_spin_unlock(&blob->bs->used_lock);
+	return allocated_bitmap;
+}
+
 /* START spdk_bs_create_blob */
 
 static void