On Fri, Oct 06, 2017 at 03:36:06PM -0700, Dan Williams wrote:
> A 'lease_direct' lease requires that the vma have a valid MAP_DIRECT
> mapping established. For xfs we establish a new lease and then check if
> the MAP_DIRECT mapping has been broken. We want to be sure that the
> process will receive notification that the MAP_DIRECT mapping is being
> torn down so it knows why other code paths are throwing failures.
>
> For example in the RDMA/ibverbs case we want ibv_reg_mr() to fail if the
> MAP_DIRECT mapping is invalid or in the process of being invalidated.
>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Dave Chinner <david@xxxxxxxxxxxxx>
> Cc: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> Cc: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
> Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
> fs/xfs/xfs_file.c | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index e35518600e28..823b65f17429 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1166,6 +1166,33 @@ xfs_filemap_direct_close(
> put_map_direct_vma(vma->vm_private_data);
> }
>
> +static struct lease_direct *
> +xfs_filemap_direct_lease(
> + struct vm_area_struct *vma,
> + void (*break_fn)(void *),
> + void *owner)
> +{
> + struct lease_direct *ld;
> +
> + ld = map_direct_lease(vma, break_fn, owner);
> +
> + if (IS_ERR(ld))
> + return ld;
> +
> + /*
> + * We now have an established lease while the base MAP_DIRECT
> + * lease was not broken. So, we know that the "lease holder" will
> + * receive a SIGIO notification when the lease is broken and
> + * take any necessary cleanup actions.
> + */
> + if (!is_map_direct_broken(vma->vm_private_data))
> + return ld;
> +
> + map_direct_lease_destroy(ld);
> +
> + return ERR_PTR(-ENXIO);
What's any of this got to do with XFS? Shouldn't it be in generic
code, and called generic_filemap_direct_lease()?
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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