diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4af7c91..d368a64 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -83,6 +83,7 @@
 	u16 available_compr_algs;
 	u16 lz4_max_distance;
 	u32 checksum;
+	u32 blocksize;
 	u16 extra_devices;
 	union {
 		u16 devt_slotoff;		/* used for mkfs */
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 4cca322..df01d2e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -99,7 +99,13 @@
 
 	sbi.build_time = le64_to_cpu(dsb->build_time);
 	sbi.build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
+	sbi.blocksize = 1 << blkszbits;
 
 	memcpy(&sbi.uuid, dsb->uuid, sizeof(dsb->uuid));
 	return erofs_init_devices(&sbi, dsb);
 }
+
+int erofs_get_blocksize(const char *filename)
+{
+	return sbi.blocksize;
+}
diff --git a/fs/fs.c b/fs/fs.c
index 2b847d8..23cfb1f 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -375,7 +375,7 @@
 		.readdir = erofs_readdir,
 		.ls = fs_ls_generic,
 		.read = erofs_read,
-		.get_blocksize = fs_get_blocksize_unsupported,
+		.get_blocksize = erofs_get_blocksize,
 		.size = erofs_size,
 		.close = erofs_close,
 		.closedir = erofs_closedir,
diff --git a/include/erofs.h b/include/erofs.h
index 1fbe82b..18bd680 100644
--- a/include/erofs.h
+++ b/include/erofs.h
@@ -10,6 +10,7 @@
 		struct disk_partition *fs_partition);
 int erofs_read(const char *filename, void *buf, loff_t offset,
 	       loff_t len, loff_t *actread);
+int erofs_get_blocksize(const char *filename);
 int erofs_size(const char *filename, loff_t *size);
 int erofs_exists(const char *filename);
 void erofs_close(void);