+ /* Process blocksize parameter if set. */
+ if (optargs_bitmask & GUESTFS_MKFS_OPTS_BLOCKSIZE_BITMASK) {
+ if (blocksize <= 0 || !is_power_of_2 (blocksize)) {
+ reply_with_error ("block size must be > 0 and a power of 2");
+ return -1;
+ }
+
+ if (STREQ (fstype, "vfat") ||
+ STREQ (fstype, "msdos")) {
+ /* For VFAT map the blocksize into a cluster size. However we
+ * have to determine the block device sector size in order to do
+ * this.
+ */
+ int sectorsize = do_blockdev_getss (device);
+ if (sectorsize == -1)
+ return -1;
+
+ int sectors_per_cluster = blocksize / sectorsize;
+ if (sectors_per_cluster < 1 || sectors_per_cluster > 128) {
+ reply_with_error ("unsupported cluster size for %s filesystem (requested cluster size = %d, sector size = %d, trying sectors per cluster = %d)",
+ fstype, blocksize, sectorsize, sectors_per_cluster);
+ return -1;
+ }
+
+ snprintf (blocksize_str, sizeof blocksize_str, "%d", sectors_per_cluster);
+ argv[i++] = "-s";
+ argv[i++] = blocksize_str;
+ }
+ else if (STREQ (fstype, "ntfs")) {
+ /* For NTFS map the blocksize into a cluster size. */
+ snprintf (blocksize_str, sizeof blocksize_str, "%d", blocksize);
+ argv[i++] = "-c";
+ argv[i++] = blocksize_str;
+ }
+ else {
+ /* For all other filesystem types, try the -b option. */
+ snprintf (blocksize_str, sizeof blocksize_str, "%d", blocksize);
+ argv[i++] = "-b";
+ argv[i++] = blocksize_str;
+ }
+ }
+
+ if (optargs_bitmask & GUESTFS_MKFS_OPTS_FEATURES_BITMASK) {
+ argv[i++] = "-O";
+ argv[i++] = features;
+ }