A 'lease_direct' lease requires that the vma have a valid MAP_DIRECT
mapping established. For xfs we use the generic_map_direct_lease()
handler for ->lease_direct(). It establishes a new lease and then checks
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 <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: "Darrick J. Wong" <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: "J. Bruce Fields" <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
---
 fs/xfs/xfs_file.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 4bee027c9366..bc512a9a8df5 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1157,6 +1157,7 @@ static const struct vm_operations_struct 
xfs_file_vm_direct_ops = {
 
        .open           = generic_map_direct_open,
        .close          = generic_map_direct_close,
+       .lease_direct   = generic_map_direct_lease,
 };
 
 static const struct vm_operations_struct xfs_file_vm_ops = {
@@ -1209,8 +1210,8 @@ xfs_file_mmap_direct(
        vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
 
        /*
-        * generic_map_direct_{open,close} expect ->vm_private_data is
-        * set to the result of map_direct_register
+        * generic_map_direct_{open,close,lease} expect
+        * ->vm_private_data is set to the result of map_direct_register
         */
        vma->vm_private_data = mds;
        return 0;

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