btrfs send/receive does not preserve +C (nocow) attribute

btrfs send/receive does not preserve +C (nocow) attribute

[Jakub Klinkovský]

[-- Attachment #1: Type: text/plain, Size: 1002 bytes --]

I've been testing btrfs send/receive, and to my surprise, the +C (nocow)
attribute I have set on directory for virtual machines images is not preserved.
Is this expected? Having found no information about this issue, I'm asking here.

Info:
$ uname -a
Linux asusntb 3.15.8-1-ARCH #1 SMP PREEMPT Fri Aug 1 08:51:42 CEST 2014 x86_64 GNU/Linux
$ btrfs --version
Btrfs v3.14.2-dirty

Both source and target btrfs filesystems are mounted with the same mount
options:
  rw,nosuid,nodev,noatime,compress=lzo,space_cache,autodefrag,commit=60

$ lsattr ~/virtual_machines/
---------------C virtual_machines/archlinux-btrfs.raw
---------------C virtual_machines/archlinux.raw
---------------C virtual_machines/winxp.raw

$ lsattr /media/backup/virtual_machines/2014-08-06/
---------------- /media/backup/virtual_machines/2014-08-06/archlinux-btrfs.raw
---------------- /media/backup/virtual_machines/2014-08-06/archlinux.raw
---------------- /media/backup/virtual_machines/2014-08-06/winxp.raw

Regards,

--
jlk

[-- Attachment #2: Type: application/pgp-signature, Size: 819 bytes --]

Re: btrfs send/receive does not preserve +C (nocow) attribute

[Juan Orti Alcaine]

El Miércoles, 6 de agosto de 2014 17:56:52 Jakub Klinkovský escribió:
> I've been testing btrfs send/receive, and to my surprise, the +C (nocow)
> attribute I have set on directory for virtual machines images is not
> preserved. Is this expected? Having found no information about this issue,
> I'm asking here.
> 
> Info:
> $ uname -a
> Linux asusntb 3.15.8-1-ARCH #1 SMP PREEMPT Fri Aug 1 08:51:42 CEST 2014
> x86_64 GNU/Linux $ btrfs --version
> Btrfs v3.14.2-dirty
> 
> Both source and target btrfs filesystems are mounted with the same mount
> options:
>   rw,nosuid,nodev,noatime,compress=lzo,space_cache,autodefrag,commit=60
> 
> $ lsattr ~/virtual_machines/
> ---------------C virtual_machines/archlinux-btrfs.raw
> ---------------C virtual_machines/archlinux.raw
> ---------------C virtual_machines/winxp.raw
> 
> $ lsattr /media/backup/virtual_machines/2014-08-06/
> ----------------
> /media/backup/virtual_machines/2014-08-06/archlinux-btrfs.raw
> ---------------- /media/backup/virtual_machines/2014-08-06/archlinux.raw
> ---------------- /media/backup/virtual_machines/2014-08-06/winxp.raw
> 
> Regards,
> 
> --
> jlk

Nor do file capabilities get preserved:
https://bugzilla.kernel.org/show_bug.cgi?id=68891