Re: [Qemu-devel] [PATCH v6 6/6] xfs: disable map_sync for async flush

Pankaj Gupta
2019-04-24T05:10:32Z

>
> On Wed, Apr 24, 2019 at 08:02:17AM +1000, Dave Chinner wrote:
> > On Tue, Apr 23, 2019 at 01:36:12PM +0530, Pankaj Gupta wrote:
> > > Dont support 'MAP_SYNC' with non-DAX files and DAX files
> > > with asynchronous dax_device. Virtio pmem provides
> > > asynchronous host page cache flush mechanism. We don't
> > > support 'MAP_SYNC' with virtio pmem and xfs.
> > >
> > > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> > > ---
> > > fs/xfs/xfs_file.c | 10 ++++++----
> > > 1 file changed, 6 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > > index 1f2e2845eb76..0e59be018511 100644
> > > --- a/fs/xfs/xfs_file.c
> > > +++ b/fs/xfs/xfs_file.c
> > > @@ -1196,11 +1196,13 @@ xfs_file_mmap(
> > > struct file *filp,
> > > struct vm_area_struct *vma)
> > > {
> > > - /*
> > > - * We don't support synchronous mappings for non-DAX files. At least
> > > - * until someone comes with a sensible use case.
> > > + struct dax_device *dax_dev = xfs_find_daxdev_for_inode
> > > + (file_inode(filp));
>
> tab separation here ^^^ ^^^^ and cut
> down the indent
> while you're at
> it, please:
>
> struct dax_device *dax_dev;
>
> dax_dev = xfs_find_daxdev_for_inode(file_inode(filp));
> if (!dax_is_frobbed(dax))
> return -EMEWANTCOOKIE;

Done.

Thanks,
Pankaj

>
> --D
>
> > > +
> > > + /* We don't support synchronous mappings for non-DAX files and
> > > + * for DAX files if underneath dax_device is not synchronous.
> > > */
> >
> > /*
> > * This is the correct multi-line comment format. Please
> > * update the patch to maintain the existing comment format.
> > */
> >
> > Cheers,
> >
> > Dave.
> > --
> > Dave Chinner
> > david@fromorbit.com
>
>