+xfs_filemap_pmd_fault(
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ pmd_t *pmd,
+ unsigned int flags)
+{
+ struct inode *inode = file_inode(vma->vm_file);
+ struct xfs_inode *ip = XFS_I(inode);
+ int ret;
+
+ if (!IS_DAX(inode))
+ return VM_FAULT_FALLBACK;
+
+ trace_xfs_filemap_pmd_fault(ip);
+
+ if (flags & FAULT_FLAG_WRITE) {
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ }
+
+ xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+ ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_dax_fault,
+ NULL);
+ xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+
+ if (flags & FAULT_FLAG_WRITE)
+ sb_end_pagefault(inode->i_sb);
+
+ return ret;
+}
+
+/*
+ * pfn_mkwrite was originally inteneded to ensure we capture time stamp
+ * updates on write faults. In reality, it's need to serialise against
+ * truncate similar to page_mkwrite. Hence we open-code dax_pfn_mkwrite()
+ * here and cycle the XFS_MMAPLOCK_SHARED to ensure we serialise the fault
+ * barrier in place.
+ */
+static int
+xfs_filemap_pfn_mkwrite(