Re: Can't cp --reflink files on a Ext4-converted FS w/o checksums

[Roman Mamedov <rm@romanrm.net>]

On Wed, 26 Nov 2014 15:18:26 -0800
Robert White <rwhite@pobox.com> wrote:

> So you _could_ reflink the file but you'd have to do it to another file 
> with no data checksums -- which basically means a NOCOW file, or 
> mounting with nodatasum while you do the reflink, but now you have more 
> problem files.

Bingo!!! A cp --reflink to a destination that's been made chattr +C prior to
that, works perfectly.

My goal was to convert regular top-level directories into subvolumes (for
further snapshotting). With that trick, I've been able to do that now w/o
issues.

$ mv Music Music.orig
$ sudo btrfs sub create Music
Create subvolume './Music'
$ sudo chattr +C Music
$ sudo cp -a --reflink Music.orig/* Music/
$ 

Finished with no rewriting necessary. After that I recursively-removed the +C
attribute from all newly reflinked files, and cp --reflink as well as
snapshotting of those works fine.

Thanks for the idea. :)

-- 
With respect,
Roman