diff --git a/kmod/src/block.c b/kmod/src/block.c
index 18f3b37e..641d9c3d 100644
--- a/kmod/src/block.c
+++ b/kmod/src/block.c
@@ -67,6 +67,7 @@ enum {
 	BLOCK_BIT_PAGE_ALLOC,	/* page (possibly high order) allocation */
 	BLOCK_BIT_VIRT,		/* mapped virt allocation */
 	BLOCK_BIT_CRC_VALID,	/* crc has been verified */
+	BLOCK_BIT_VISITED,	/* used by callers to track blocks */
 };
 
 struct block_private {
@@ -128,6 +129,22 @@ bool scoutfs_block_valid_ref(struct super_block *sb,
 	       hdr->blkno == blkno;
 }
 
+bool scoutfs_block_tas_visited(struct super_block *sb,
+			       struct scoutfs_block *bl)
+{
+	struct block_private *bp = BLOCK_PRIVATE(bl);
+
+	return test_bit(BLOCK_BIT_VISITED, &bp->bits) != 0;
+}
+
+void scoutfs_block_clear_visited(struct super_block *sb,
+				 struct scoutfs_block *bl)
+{
+	struct block_private *bp = BLOCK_PRIVATE(bl);
+
+	clear_bit(BLOCK_BIT_VISITED, &bp->bits);
+}
+
 static struct block_private *block_alloc(struct super_block *sb, u64 blkno)
 {
 	struct block_private *bp;
diff --git a/kmod/src/block.h b/kmod/src/block.h
index dbb0d54c..abcdd440 100644
--- a/kmod/src/block.h
+++ b/kmod/src/block.h
@@ -17,6 +17,10 @@ bool scoutfs_block_valid_crc(struct scoutfs_block_header *hdr);
 bool scoutfs_block_valid_ref(struct super_block *sb,
 			     struct scoutfs_block_header *hdr,
 			     __le64 seq, __le64 blkno);
+bool scoutfs_block_tas_visited(struct super_block *sb,
+			       struct scoutfs_block *bl);
+void scoutfs_block_clear_visited(struct super_block *sb,
+				 struct scoutfs_block *bl);
 
 struct scoutfs_block *scoutfs_block_create(struct super_block *sb, u64 blkno);
 struct scoutfs_block *scoutfs_block_read(struct super_block *sb, u64 blkno);