do_mkfs_b (const char *fstype, int blocksize, const char *device)
{
const char *extra[2];
- char blocksize_s[32];
+ char n[32];
if (blocksize <= 0 || !is_power_of_2 (blocksize)) {
reply_with_error ("block size must be > 0 and a power of 2");
return -1;
}
- snprintf (blocksize_s, sizeof blocksize_s, "%d", blocksize);
-
- extra[0] = "-b";
- extra[1] = blocksize_s;
+ 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 (n, sizeof n, "%d", sectors_per_cluster);
+ extra[0] = "-s";
+ extra[1] = n;
+ }
+ else if (STREQ (fstype, "ntfs")) {
+ /* For NTFS map the blocksize into a cluster size. */
+ snprintf (n, sizeof n, "%d", blocksize);
+ extra[0] = "-c";
+ extra[1] = n;
+ }
+ else {
+ /* For all other filesystem types, try the -b option. */
+ snprintf (n, sizeof n, "%d", blocksize);
+ extra[0] = "-b";
+ extra[1] = n;
+ }
return mkfs (fstype, device, extra, 2);
}