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 <[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 | 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); +} + static const struct vm_operations_struct xfs_file_vm_direct_ops = { .fault = xfs_filemap_fault, .huge_fault = xfs_filemap_huge_fault, @@ -1175,6 +1202,7 @@ static const struct vm_operations_struct xfs_file_vm_direct_ops = { .open = xfs_filemap_direct_open, .close = xfs_filemap_direct_close, + .lease_direct = xfs_filemap_direct_lease, }; static const struct vm_operations_struct xfs_file_vm_ops = { _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
