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

Dan Williams
2019-05-07T15:37:14Z

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?

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