lvcreate throws error : device not cleared

["J. B" <bakshi12@gmail.com>]

Dear list,

I'm with debian wheezy with lvm2 2.02.95-4.

whenever I try to execute lvcreate it fails. Here is the output of such
a command

``````````````````
#lvcreate -v -n root -L 80G mygroup

    Setting logging type to disk
    Finding volume group "mygroup"
    Archiving volume group "mygroup" metadata (seqno 7).
    Creating logical volume root
    Creating volume group backup "/etc/lvm/backup/mygroup" (seqno 8).
    Found volume group "mygroup"
    activation/volume_list configuration setting not defined: Checking only host tags for mygroup/root
    Creating mygroup-root
    Loading mygroup-root table (254:1)
    Resuming mygroup-root (254:1)
    Clearing start of logical volume "root"
  /dev/mygroup/root: not found: device not cleared
  Aborting. Failed to wipe start of new LV.
    Found volume group "mygroup"
    Removing mygroup-root (254:1)
    Creating volume group backup "/etc/lvm/backup/mygroup" (seqno 9).
  semid 7340034: semop failed for cookie 0xd4ddd6c: incorrect semaphore state
  Failed to set a proper state for notification semaphore identified by cookie value 223206764 (0xd4ddd6c) to initialize waiting for incoming notifications.
`````````````````````````

Am I missing anything ?

Thanks