[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion

- When xdatum is removed, a new xdatum with 'delete marker' is
  written. (version==0xffffffff means 'delete marker')
- When xref is removed, a new xref with 'delete marker' is written.
  (odd-numbered xseqno means 'delete marker')

- delete_xattr_(datum/xref)_delay() are new deletion functions
  are added. We can only use them if we can detect the target
  obsolete xdatum/xref as a orphan or errir one.
  (e.g when inode deletion, or detecting crc error)

[1/3] jffs2-xattr-v6-01-delete_marker.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/fs/jffs2/malloc.c b/fs/jffs2/malloc.c
index 4889d07..8310c95 100644
--- a/fs/jffs2/malloc.c
+++ b/fs/jffs2/malloc.c
@@ -291,6 +291,7 @@
 
 	memset(xd, 0, sizeof(struct jffs2_xattr_datum));
 	xd->class = RAWNODE_CLASS_XATTR_DATUM;
+	xd->node = (void *)xd;
 	INIT_LIST_HEAD(&xd->xindex);
 	return xd;
 }
@@ -309,6 +310,7 @@
 
 	memset(ref, 0, sizeof(struct jffs2_xattr_ref));
 	ref->class = RAWNODE_CLASS_XATTR_REF;
+	ref->node = (void *)ref;
 	return ref;
 }