Re: [Qemu-devel] [PATCH v7 6/6] xfs: disable map_sync for async flush

Pankaj Gupta
2019-05-08T05:49:08Z

>
> On Tue, May 07, 2019 at 08:37:01AM -0700, Dan Williams wrote:
> > On Thu, Apr 25, 2019 at 10:03 PM Pankaj Gupta <pagupta@redhat.com> 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 | 9 ++++++---
> > > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > Darrick, does this look ok to take through the nvdimm tree?
>
> <urk> forgot about this, sorry. :/
>
> > >
> > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > > index a7ceae90110e..f17652cca5ff 100644
> > > --- a/fs/xfs/xfs_file.c
> > > +++ b/fs/xfs/xfs_file.c
> > > @@ -1203,11 +1203,14 @@ xfs_file_mmap(
> > > struct file *filp,
> > > struct vm_area_struct *vma)
> > > {
> > > + struct dax_device *dax_dev;
> > > +
> > > + dax_dev = xfs_find_daxdev_for_inode(file_inode(filp));
> > > /*
> > > - * We don't support synchronous mappings for non-DAX files. At
> > > least
> > > - * until someone comes with a sensible use case.
> > > + * We don't support synchronous mappings for non-DAX files and
> > > + * for DAX files if underneath dax_device is not synchronous.
> > > */
> > > - if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
> > > + if (!daxdev_mapping_supported(vma, dax_dev))
> > > return -EOPNOTSUPP;
>
> LGTM, and I'm fine with it going through nvdimm. Nothing in
> xfs-5.2-merge touches that function so it should be clean.
>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

Thank you for the review.

Pankaj

>
> --D
>
> > >
> > > file_accessed(filp);
> > > --
> > > 2.20.1
> > >
>
>