cifs: add fiemap support

Useful for improved copy performance as well as for
applications which query allocated ranges of sparse
files.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsglob.h

@@ -493,6 +493,9 @@ struct smb_version_operations {
 			 char *full_path,
 			 umode_t mode,
 			 dev_t device_number);
+	/* version specific fiemap implementation */
+	int (*fiemap)(struct cifs_tcon *tcon, struct cifsFileInfo *,
+		      struct fiemap_extent_info *, u64, u64);
 };
 
 struct smb_version_values {