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@xxxxxxxxxx> --- fs/xfs/xfs_file.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index e474250..eae4aa4 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1190,6 +1190,14 @@ xfs_file_mmap( if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC)) return -EOPNOTSUPP; + /* We don't support synchronous mappings with guest direct access + * and virtio based host page cache mechanism. + */ + if (IS_DAX(file_inode(filp)) && virtio_pmem_host_cache_enabled( + xfs_find_daxdev_for_inode(file_inode(filp))) && + (vma->vm_flags & VM_SYNC)) + return -EOPNOTSUPP; + file_accessed(filp); vma->vm_ops = &xfs_file_vm_ops; if (IS_DAX(file_inode(filp))) -- 2.9.3
