--- mkdosfs/mkdosfs.c.orig 2005-03-12 17:12:16.000000000 +0100 +++ mkdosfs/mkdosfs.c.orig 2005-11-14 15:47:26.000000000 +0100 @@ -769,18 +769,19 @@ size_fat = 32; } if (size_fat == 32) { - /* For FAT32, try to do the same as M$'s format command: - * fs size < 256M: 0.5k clusters - * fs size < 8G: 4k clusters - * fs size < 16G: 8k clusters - * fs size >= 16G: 16k clusters + /* For FAT32, try to do the same as M$'s format command + * (see http://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf p. 20): + * fs size <= 260M: 0.5k clusters + * fs size <= 8G: 4k clusters + * fs size <= 16G: 8k clusters + * fs size > 16G: 16k clusters */ unsigned long sz_mb = (blocks+(1<<(20-BLOCK_SIZE_BITS))-1) >> (20-BLOCK_SIZE_BITS); - bs.cluster_size = sz_mb >= 16*1024 ? 32 : - sz_mb >= 8*1024 ? 16 : - sz_mb >= 256 ? 8 : - 1; + bs.cluster_size = sz_mb > 16*1024 ? 32 : + sz_mb > 8*1024 ? 16 : + sz_mb > 260 ? 8 : + 1; } else { /* FAT12 and FAT16: start at 4 sectors per cluster */ @@ -1036,6 +1037,8 @@ break; case 32: + if (clust32 < MIN_CLUST_32) + fprintf(stderr, "WARNING: Not enough clusters for a 32 bit FAT!\n"); cluster_count = clust32; fat_length = fatlength32; bs.fat_length = CT_LE_W(0);