Re: [PATCH 04/27] kill filp_open()

Bryn M. Reeves
2008-01-16T17:14:46Z

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Dave Hansen wrote:
> On Wed, 2008-01-16 at 00:52 -0800, Andrew Morton wrote:
>> On Thu, 01 Nov 2007 16:08:31 -0700 Dave Hansen <haveblue@us.ibm.com> wrote:
>>> Replace all callers with open_namei() directly, and move the
>>> nameidata stack allocation into open_namei().
>> ftp://ftp.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-loop.patch
>> is using filp_open() and hence doesn't work very well.
>>
>> A shall revert dm-loop.patch and run away.
>
> This one's pretty easy, thank goodness. Just replace filp_open() with
> open_namei():
>
> /filp_open(/open_namei(AT_FDCWD, /
>
> BTW, why do we need this on top of the existing loopback driver? Can
> they really share no code?

The current dm-loop patch was really written to demonstrate the value of
block-mapping as an alternative to doing file backed I/O via the pagecache.

Personally, I would like to see a single "loopback block devices" driver
in the kernel with loop.c and dm-loop as alternate interfaces to it.

There seems to be some demand for this, e.g.:

http://bugzilla.kernel.org/show_bug.cgi?id=5333

And numerous similar posts to dm-devel (although I think obsoleting may
be going a bit far to start with!).

Regards,
Bryn.
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