blobstore: export allocated cluster bitmap for a blob

Signed-off-by: Tiago Castro <[email protected]>

include/spdk/bit_array.h

@@ -16,10 +16,14 @@
 extern "C" {
 #endif
 
+typedef uint64_t spdk_bit_array_word;
 /**
  * Variable-length bit array.
  */
-struct spdk_bit_array;
+struct spdk_bit_array {
+	uint32_t bit_count;
+	spdk_bit_array_word words[];
+};
 
 /**
  * Return the number of bits that a bit array is currently sized to hold.

include/spdk/blob.h

@@ -35,6 +35,7 @@
 
 #include "spdk/stdinc.h"
 #include "spdk/assert.h"
+#include "spdk/bit_array.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -1180,6 +1181,30 @@ bool spdk_blob_is_degraded(const struct spdk_blob *blob);
  */
 void spdk_blob_reset_used_clusters_cache(struct spdk_blob *blob);
 
+/**
+ * Blob get cluster bitmap completion callback.
+ *
+ * \param cb_arg Callback argument.
+ * \param bserrno 0 if it completed successfully, or negative errno if it failed.
+ * \param bitmap NULL if no memory available, otherwise a bitmap where each bit corresponds
+ * to a cluster. A set bit indicates the cluster is owned by the blob.
+ */
+typedef void (*spdk_blob_cluster_bitmap_complete)(void *cb_arg, int bserrno,
+		struct spdk_bit_array *bitmap);
+
+/**
+ * Get the allocated cluster bitmap of the given blob.
+ *
+ * \param blob Blob to retrieve allocated bitmap from.
+ * \param cb_fn Called when the operation is complete.
+ * \param cb_arg Custom cb_arg passed to function cb_fn.
+ *
+ * \return 0 if callback was called, or negative errno otherwise.
+ */
+int
+spdk_blob_get_cluster_bitmap(struct spdk_blob *blob, spdk_blob_cluster_bitmap_complete cb_fn,
+			     void *cb_arg);
+
 #ifdef __cplusplus
 }
 #endif

lib/blob/blobstore.c

@@ -11,7 +11,6 @@
 #include "spdk/env.h"
 #include "spdk/queue.h"
 #include "spdk/thread.h"
-#include "spdk/bit_array.h"
 #include "spdk/bit_pool.h"
 #include "spdk/likely.h"
 #include "spdk/util.h"
@@ -5985,6 +5984,37 @@ spdk_blob_reset_used_clusters_cache(struct spdk_blob *blob)
 		spdk_spin_unlock(&blob->bs->used_lock);
 	}
 }
+
+int
+spdk_blob_get_cluster_bitmap(struct spdk_blob *blob, spdk_blob_cluster_bitmap_complete cb_fn,
+			     void *cb_arg)
+{
+	struct spdk_bit_array *allocated_bitmap;
+	uint64_t i;
+
+	/* Only snapshots are supported at the moment. */
+	if (!blob->data_ro || !blob->md_ro) {
+		return -EPERM;
+	}
+
+	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);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < blob->active.num_clusters; i++) {
+		if (blob->active.clusters[i]) {
+			spdk_bit_array_set(allocated_bitmap, i);
+		}
+	}
+
+	cb_fn(cb_arg, 0, allocated_bitmap);
+	spdk_bit_array_free(&allocated_bitmap);
+
+	return 0;
+}
+
 /* START spdk_bs_create_blob */
 
 static void

lib/util/bit_array.c

@@ -12,7 +12,6 @@
 #include "spdk/likely.h"
 #include "spdk/util.h"
 
-typedef uint64_t spdk_bit_array_word;
 #define SPDK_BIT_ARRAY_WORD_TZCNT(x)	(__builtin_ctzll(x))
 #define SPDK_BIT_ARRAY_WORD_POPCNT(x)	(__builtin_popcountll(x))
 #define SPDK_BIT_ARRAY_WORD_C(x)	((spdk_bit_array_word)(x))
@@ -21,11 +20,6 @@ typedef uint64_t spdk_bit_array_word;
 #define SPDK_BIT_ARRAY_WORD_INDEX_SHIFT	spdk_u32log2(SPDK_BIT_ARRAY_WORD_BITS)
 #define SPDK_BIT_ARRAY_WORD_INDEX_MASK	((1u << SPDK_BIT_ARRAY_WORD_INDEX_SHIFT) - 1)
 
-struct spdk_bit_array {
-	uint32_t bit_count;
-	spdk_bit_array_word words[];
-};
-
 struct spdk_bit_array *
 spdk_bit_array_create(uint32_t num_bits)
 {
@@ -335,6 +329,28 @@ spdk_bit_array_clear_mask(struct spdk_bit_array *ba)
 	}
 }
 
+void
+spdk_bit_array_print(struct spdk_bit_array *ba)
+{
+	uint32_t i;
+	uint32_t num_bits = spdk_bit_array_capacity(ba);
+
+	printf("bit_count: %d\n", ba->bit_count);
+	printf("num_bits: %d\n", num_bits);
+	printf("num_bits: %d\n", num_bits % CHAR_BIT);
+
+	printf("SPDK_BIT_ARRAY_WORD_BYTES: %ld\n", SPDK_BIT_ARRAY_WORD_BYTES);
+	printf("SPDK_BIT_ARRAY_WORD_BITS: %ld\n", SPDK_BIT_ARRAY_WORD_BITS);
+	printf("SPDK_BIT_ARRAY_WORD_INDEX_SHIFT: %d\n", SPDK_BIT_ARRAY_WORD_INDEX_SHIFT);
+	printf("SPDK_BIT_ARRAY_WORD_INDEX_MASK: %d\n", SPDK_BIT_ARRAY_WORD_INDEX_MASK);
+
+	for (i = 0; i < num_bits; i++) {
+		if (spdk_bit_array_get(ba, i)) {
+			printf("i: %d, set: 1\n", i);
+		}
+	}
+}
+
 struct spdk_bit_pool {
 	struct spdk_bit_array	*array;
 	uint32_t		lowest_free_bit;