1 files changed, 85 insertions, 0 deletions
diff --git a/tools/blktap/drivers/block-qcow2.c b/tools/blktap/drivers/block-qcow2.c
index 8bdd33ea37..744022697c 100644
--- a/tools/blktap/drivers/block-qcow2.c
+++ b/tools/blktap/drivers/block-qcow2.c
@@ -1980,6 +1980,91 @@ static int qcow_validate_parent(struct disk_driver *child,
 	return 0;
 }
 
+int qcow2_create(const char *filename, uint64_t total_size,
+                      const char *backing_file, int flags)
+{
+    int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
+    QCowHeader header;
+    uint64_t tmp, offset;
+    QCowCreateState s1, *s = &s1;
+
+    memset(s, 0, sizeof(*s));
+
+    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+    if (fd < 0)
+        return -1;
+    memset(&header, 0, sizeof(header));
+    header.magic = cpu_to_be32(QCOW_MAGIC);
+    header.version = cpu_to_be32(QCOW_VERSION);
+    header.size = cpu_to_be64(total_size * 512);
+    header_size = sizeof(header);
+    backing_filename_len = 0;
+    if (backing_file) {
+        header.backing_file_offset = cpu_to_be64(header_size);
+        backing_filename_len = strlen(backing_file);
+        header.backing_file_size = cpu_to_be32(backing_filename_len);
+        header_size += backing_filename_len;
+    }
+    s->cluster_bits = 12;  /* 4 KB clusters */
+    s->cluster_size = 1 << s->cluster_bits;
+    header.cluster_bits = cpu_to_be32(s->cluster_bits);
+    header_size = (header_size + 7) & ~7;
+    if (flags & BLOCK_FLAG_ENCRYPT) {
+        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
+    } else {
+        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
+    }
+    l2_bits = s->cluster_bits - 3;
+    shift = s->cluster_bits + l2_bits;
+    l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
+    offset = align_offset(header_size, s->cluster_size);
+    s->l1_table_offset = offset;
+    header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
+    header.l1_size = cpu_to_be32(l1_size);
+    offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
+
+    s->refcount_table = qemu_mallocz(s->cluster_size);
+    s->refcount_block = qemu_mallocz(s->cluster_size);
+
+    s->refcount_table_offset = offset;
+    header.refcount_table_offset = cpu_to_be64(offset);
+    header.refcount_table_clusters = cpu_to_be32(1);
+    offset += s->cluster_size;
+
+    s->refcount_table[0] = cpu_to_be64(offset);
+    s->refcount_block_offset = offset;
+    offset += s->cluster_size;
+
+    /* update refcounts */
+    create_refcount_update(s, 0, header_size);
+    create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t));
+    create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
+    create_refcount_update(s, s->refcount_block_offset, s->cluster_size);
+
+    /* write all the data */
+    write(fd, &header, sizeof(header));
+    if (backing_file) {
+        write(fd, backing_file, backing_filename_len);
+    }
+    lseek(fd, s->l1_table_offset, SEEK_SET);
+    tmp = 0;
+    for(i = 0;i < l1_size; i++) {
+        write(fd, &tmp, sizeof(tmp));
+    }
+    lseek(fd, s->refcount_table_offset, SEEK_SET);
+    write(fd, s->refcount_table, s->cluster_size);
+
+    lseek(fd, s->refcount_block_offset, SEEK_SET);
+    write(fd, s->refcount_block, s->cluster_size);
+
+    qemu_free(s->refcount_table);
+    qemu_free(s->refcount_block);
+    close(fd);
+    return 0;
+}
+
+
+
 struct tap_disk tapdisk_qcow2 = {
 	"qcow2",
 	sizeof(BDRVQcowState),