Re: State of nocow file attribute

[Liu Bo <bo.li.liu@oracle.com>]

On 08/15/2012 06:12 PM, Lluís Batlle i Rossell wrote:
> Hello,
> 
> some time ago we discussed on #btrfs that the nocow attribute for files wasn't
> working (around 3.3 or 3.4 kernels). That was evident by files fragmenting even
> with the attribute set.
> 
> Chris mentioned to find a fix quickly for that, and posted some lines of change
> into irc. But recently someone mentioned that 3.6-rc looks like still not
> respecting nocow for files.
> 
> Is there really a fix upstream for that? Do nocow attribute on files work for
> anyone already?
> 

Hi Lluís,

Dave had post a patch to fix it but only enabling NOCOW with zero sized file.

FYI, the patch is http://article.gmane.org/gmane.comp.file-systems.btrfs/17351

With the patch, you don't need to mount with nodatacow any more :)

And why it is only for only zero sized file:
http://permalink.gmane.org/gmane.comp.file-systems.btrfs/18046

thanks,
liubo

> Regards,
> Lluís.
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