mke2fs freezes with device-mapper device

Hi! mke2fs with simple block device (l4linux + atapi drv) work's correctly, but if i create encrypted device with cryptsetup, open it (there device mapper file created) and try to create file system (on dm-device) using mke2fs then system freezes(infinitely write to device). I found that problem in fsync call at unix_flush(io_channel channel) function (mke2fs_source/lib/ext2fs/unix_io.c). Help me to solve this problem) .run file attached initrd with cryptsetup - https://github.com/shomich/files/blob/master/initrd.gz