Index: sys/fs/msdosfs/msdosfs_vfsops.c
===================================================================
--- sys/fs/msdosfs/msdosfs_vfsops.c
+++ sys/fs/msdosfs/msdosfs_vfsops.c
@@ -577,7 +577,6 @@
 		goto error_exit;
 	}
 
-	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
 	if ((off_t)pmp->pm_HugeSectors * pmp->pm_BytesPerSec <
 	    pmp->pm_HugeSectors /* overflow */ ||
 	    (off_t)pmp->pm_HugeSectors * pmp->pm_BytesPerSec >
@@ -586,6 +585,7 @@
 		goto error_exit;
 	}
 
+	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec;	/* XXX not used? */
 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
 	SecPerClust         *= pmp->pm_BlkPerSec;