Re: [RFC] The reflink(2) system call v2.

[Joel Becker <Joel.Becker@oracle.com>]

On Mon, May 11, 2009 at 06:49:01PM -0400, jim owens wrote:
> Joel Becker wrote:
>> On Thu, May 07, 2009 at 10:59:04PM -0400, jim owens wrote:
>>> - fix the
>>> +	if (S_ISDIR(inode->i_mode))
>>> +		return -EPERM;
>>>
>>>   to be an ISREG check unless you have an argument for
>>>   special files and symlinks being COWed.
>>
>> 	Jim, if you have a real problem this prevents, I'm all ears.
>> And if others concur that restricting it to regular files is the right
>> way to go, I can be convinced.
>
> My only problem was my past experience on non-Linux systems
> where once we said it works for multiple file types, we had
> to support that forever across all filesystems.  We could add
> support for more types but not eliminate supported ones.

	Someone else pointed out that a naive user might reflink a block
device file and expect the device contents to be copied-on-write.
Obviously wrong if you understand filesystems, but let's just prevent
that misunderstanding.  S_ISREG() it is.

Joel

-- 

"All alone at the end of the evening
 When the bright lights have faded to blue.
 I was thinking about a woman who had loved me
 And I never knew"

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127