Re: [PATCH 4/6] libxfs: reused invalidated buffers leak state and data

Dave Chinner
2014-07-06T23:54:55Z

On Sat, Jul 05, 2014 at 02:48:07AM -0700, Christoph Hellwig wrote:
> On Sat, Jul 05, 2014 at 08:22:10AM +1000, Dave Chinner wrote:
> > I'm open to other ways of fixing this, but right now we've got to
> > fix xfs_repair because it's currently breaking filesystems worse
> > than before xfs_repair was run...
>
> Ok, so clearly mark this as difference from kernel code in a long
> comment explaining the situation similar to wrote you above.

Will do.

> It's
> pretty obvious that the buffer cache in userspace will eventually need
> a major overhaul sooner or later. I wonder how feasible porting the
> kernel one would be..

It's not so much the porting that's the issue - it's cleaning up all
the applications that use it that is the headache. And,
realistically, I don't think there's much of the kernel code that
can be used - we have to rewrite all the allocation, freeing,
locking and IO parts of it, so we'd pretty much be re-implementing
most of it, anyway....

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com