Re: [Qemu-devel] [PATCH v4 5/5] xfs: disable map_sync for async flush

[Pankaj Gupta]

> 
> On Thu, Apr 04, 2019 at 02:12:30AM -0400, Pankaj Gupta wrote:
> > > All this ad hoc IS_DAX conditional logic is getting pretty nasty.
> > > 
> > > xfs_file_mmap(
> > > ....
> > > {
> > >   struct inode    *inode = file_inode(filp);
> > > 
> > >   if (vma->vm_flags & VM_SYNC) {
> > >           if (!IS_DAX(inode))
> > >                   return -EOPNOTSUPP;
> > >           if (!dax_synchronous(xfs_find_daxdev_for_inode(inode))
> > >                   return -EOPNOTSUPP;
> > >   }
> > > 
> > >   file_accessed(filp);
> > >   vma->vm_ops = &xfs_file_vm_ops;
> > >   if (IS_DAX(inode))
> > >           vma->vm_flags |= VM_HUGEPAGE;
> > >   return 0;
> > > }
> > 
> > Sure, this is better.
> 
> > > Even better, factor out all the "MAP_SYNC supported" checks into a
> > > helper so that the filesystem code just doesn't have to care about
> > > the details of checking for DAX+MAP_SYNC support....
> > 
> > o.k. Will add one common helper function for both ext4 & xfs filesystems.
> 
> Note this pending patch for Goldwyn Rodrigues' patchset for btrfs:
> 
> https://lore.kernel.org/linux-btrfs/address@hidden/
> 
> We might want to coordinate.

Sure. Good to know.

Thanks for the pointer. Will have a look.

Best regards,
Pankaj 

> 
> 
> Meow!
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