Description of problem:
I cannot snapshot neither directory nor whole volume using btrfsprogs in F11.
I have LUKS-encrypted partition, over it I have single partition btrfs:

/dev/dm-5 on /media/WDP-Crypt type btrfs (rw,nosuid,nodev,uhelper=devkit)


Version-Release number of selected component (if applicable):
btrfs-progs-0.18-4.fc11.x86_64
kernel-2.6.29.4-167.fc11.x86_64


[root@gilbertus ~]# btrfsctl -s back_2009-06-02_01 /media/WDP-Crypt/Backup/
ioctl:: Inappropriate ioctl for device
[root@gilbertus ~]# btrfsctl -s back_2009-06-02_01 /media/WDP-Crypt/
ioctl:: Inappropriate ioctl for device
[root@gilbertus ~]# btrfsctl -s back_2009-06-02_01 /dev/dm-5 
ioctl:: Inappropriate ioctl for device
  

After some stracing and debugging I found following two errors in btrfsctl.c:
1) snapshot name is treated as directory to be snapshotted
2) dirname() strips the parameter and leaves "." as dir to be snapshotted. This happens after following lines in btrfsctl.c:

 snap_location = strdup(fullpath);
 snap_location = dirname(snap_location);

(snap_location equals "." afterwards). Look into following strace snippet:

stat(".", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=20480, ...}) = 0
open(".", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
fcntl(3, F_GETFD)                       = 0x1 (flags FD_CLOEXEC)
stat("/media/WDP-Crypt/Backup/", {st_mode=S_IFDIR|0755, st_size=82, ...}) = 0
open("/media/WDP-Crypt/Backup/", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 4
ioctl(3, 0x50009401, 0x7ffff3e192e0)    = -1 ENOTTY (Inappropriate ioctl for device)


first "." is opened as fd3, then correct dir as fd4, and lastly *fd3* is snapshotted.