Kernel 3.7 + slower snapshot then usual

[Sylvain Alain <d2racing911@gmail.com>]

Hi guys, I noticed that now my snapshot take a long time to process :

sylvain@gentootux ~ $ df -h
Sys. de fichiers Taille Utilisé Dispo Uti% Monté sur
rootfs             112G    4,0G  103G   4% /
/dev/sda4          112G    4,0G  103G   4% /
tmpfs              7,9G    596K  7,9G   1% /run
udev                10M       0   10M   0% /dev
none               7,9G       0  7,9G   0% /dev/shm
cgroup_root         10M       0   10M   0% /sys/fs/cgroup
tmpfs               12G       0   12G   0% /var/tmp/portage
/dev/sdb2          224G     52G  173G  23% /mnt/win_c
/dev/sdc2          912G    412G  500G  46% /mnt/win_d

sylvain@gentootux ~ $ su -
Mot de passe :

gentootux ~ # mount /dev/sda4 -o
noatime,ssd,discard,compress=lzo,noacl,space_cache,subvolid=0
/mnt/disklayout/

gentootux ~ # cd /mnt/disklayout/

gentootux disklayout # ls
@backup  @racine

gentootux disklayout # time btrfs subvolume delete @backup
Delete subvolume '/mnt/disklayout/@backup'

real 0m0.020s
user 0m0.001s
sys 0m0.002s
gentootux disklayout # ls
@racine

gentootux disklayout # time btrfs subvolume snapshot @racine @backup
Create a snapshot of '@racine' in './@backup'

real 6m9.122s
user 0m0.000s
sys 0m0.523s

more then 6 minutes to snapshot 4 gigs of data, that's twice slower
then kernel 3.6.

Is there any log or something that I look after ?

sylvain@gentootux ~ $ sudo dmesg | grep -i btrfs
[    0.371528] Btrfs loaded
[    0.784593] btrfs: disk space caching is enabled
[    0.788680] Btrfs detected SSD devices, enabling SSD mode
[    0.789757] VFS: Mounted root (btrfs filesystem) readonly on device 0:12.
[    4.881241] btrfs: use ssd allocation scheme
[    4.881244] btrfs: use lzo compression
[    4.881245] btrfs: disk space caching is enabled
[  496.982616] btrfs: unlinked 14 orphans

Thanks !


--
Salut
alp
Sylvain