lvm2 and initrd

I wonder if my initrd affects the system, because after running the initrd, the VFS is unable to detect any partition of my group volume. Although "vgscan" and "vgchange -a y" detect the group volume.

Here is what initrd is doing (and me) :

Found volume group "vglfs" using metadata type lvm2 6 logical volume(s) in volume group "vglfs" now active
sh: no job control in this shell
ls -l /dev/mapper/{control,vglfs-racine}

crw-------   1 0            0             10, 63 Sep 9 23:19 control
brw-------   1 0            0            254,  0 Sep 9 23:20 vglfs-racine

sh-2.05b# mount /dev/mapper/vglfs-racine /tmp/
found reiserfs format "3.6" with standard journal
Reiserfs journal params: device dm-0, size 8192, journal first block 18, max tra ns len 1024, max batch 908, max commit age 30, max trans age 30
reiserfs: checking transaction log (dm-0) for (dm-0)
Using r5 hash to sort names

sh-2.05b# exit
VFS: Cannot open root device "mapper/vglfs-racine" or unknown-block(0,0) Please append a correct "root=" boot option

Kernel panic: VFS: Unable to mount root fs on unknown-block(0,0)

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Anyone got an idea ?

Guillaume.