[First installation problem with LUKS+LVM+BTRFS]

ok you`ve right but now after the correct installation with only luks and lvm I`ve the following error 

 

   device-mapper: reload ioctl failed:No such file or directory 
Failed to setup dm-crypt key mapping for device /dev/sda2
Check that kernel supports twofish-xts-plain cipher 

I checked the kernel config and appears correct, the output of lsmod is the following

 

 Module                  Size  Used by
dm_crypt               20642  1 
twofish_generic        16486  0 
twofish_avx_x86_64     45424  2 
twofish_x86_64_3way    25488  1 twofish_avx_x86_64
twofish_x86_64         12570  2 twofish_avx_x86_64,twofish_x86_64_3way
twofish_common         20723  4 twofish_generic,twofish_avx_x86_64,twofish_x86_64_3way,twofish_x86_64
ccm                    16515  1 
arc4                   12390  2 
ath9k                 111518  0 
ath9k_common           12926  1 ath9k
ath9k_hw              374655  2 ath9k_common,ath9k
ath3k                  12437  0 
ath                    22071  3 ath9k_common,ath9k,ath9k_hw
btusb                  24725  0 
mac80211              421465  1 ath9k
bluetooth             258391  3 ath3k,btusb
x86_pkg_temp_thermal    12390  0 
hid_multitouch         12437  0 
coretemp               12390  0 
iTCO_wdt               12390  0 
crct10dif_pclmul       12479  0 
crc32_pclmul           12483  0 
cfg80211              320349  3 ath,ath9k,mac80211
crc32c_intel           16568  0 
iTCO_vendor_support    12938  1 iTCO_wdt
6lowpan_iphc           16649  1 bluetooth
ghash_clmulni_intel    12523  0 
microcode              41719  0 
joydev                 16535  0 
serio_raw              12439  0 
lpc_ich                20629  0 
mei_me                 12576  0 
mfd_core               12807  1 lpc_ich
mei                    58244  1 mei_me
i2c_i801               16533  0 
ideapad_laptop         16575  0 
shpchp                 29571  0 
sparse_keymap          13019  1 ideapad_laptop
rfkill                 18094  4 cfg80211,ideapad_laptop,bluetooth
raid10                 37123  0 
raid456                57671  0 
async_raid6_recov      12621  1 raid456
async_pq               12640  2 raid456,async_raid6_recov
async_xor              12573  3 async_pq,raid456,async_raid6_recov
async_memcpy           12464  2 raid456,async_raid6_recov
async_tx               12840  5 async_pq,raid456,async_xor,async_memcpy,async_raid6_recov
raid1                  28900  0 
raid0                  16515  0 
multipath              12390  0 
linear                 12390  0 
usb_storage            52365  1 
nouveau               793903  1 
ttm                    66567  1 nouveau
i915                  586099  2 
mxm_wmi                12672  1 nouveau
drm_kms_helper         37632  2 i915,nouveau
drm                   216971  6 ttm,i915,drm_kms_helper,nouveau
i2c_algo_bit           12633  2 i915,nouveau
i2c_core               28590  6 drm,i915,i2c_i801,drm_kms_helper,i2c_algo_bit,nouveau
r8169                  49390  0 
mii                    13085  1 r8169
wmi                    13114  2 mxm_wmi,nouveau
video                  16832  2 i915,nouveau
 

How can I solve this problem

[First installation problem with LUKS+LVM+BTRFS]

This is my first installation with funtoo. I have used a combination of luks and lvm that is I encrypted the partition /dev/sda2. After I've created three volume root, home and portage and formatted with btrfs. The mount point are respectively: /mnt/funtoo, /mnt/funtoo/home,/mnt/funtoo/usr/portage. The sda1 is vfat efi partition where I installed the grub2 . The kernel is debian-sources. The boot.conf is the following

"Funtoo Linux General" { 
kernel kernel[-v] 
initrd initramfs[-v] 
params += crypt_root=/dev/sda2 dolvm real_root=/dev/mapper/vg-root rootfstype=btrfs
} 

The boot-boot-update don't has errors. My question is the following during the boot I have this error:

No volume groups found. Block device /dev/mapper/vg-root is not a valid root device. Could not find the root block device in .

Where I wrong ?