[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

fs/jffs2/nodelist.h

@@ -20,6 +20,8 @@
 #include <linux/jffs2.h>
 #include "jffs2_fs_sb.h"
 #include "jffs2_fs_i.h"
+#include "xattr.h"
+#include "acl.h"
 #include "summary.h"
 
 #ifdef __ECOS
@@ -107,11 +109,16 @@ struct jffs2_inode_cache {
 		temporary lists of dirents, and later must be set to
 		NULL to mark the end of the raw_node_ref->next_in_ino
 		chain. */
+	u8 class;	/* It's used for identification */
+	u8 flags;
+	uint16_t state;
 	struct jffs2_inode_cache *next;
 	struct jffs2_raw_node_ref *nodes;
 	uint32_t ino;
 	int nlink;
-	int state;
+#ifdef CONFIG_JFFS2_FS_XATTR
+	struct list_head ilist;
+#endif
 };
 
 /* Inode states for 'state' above. We need the 'GC' state to prevent
@@ -125,6 +132,12 @@ struct jffs2_inode_cache {
 #define INO_STATE_READING	5	/* In read_inode() */
 #define INO_STATE_CLEARING	6	/* In clear_inode() */
 
+#define INO_FLAGS_XATTR_CHECKED	0x01	/* has no duplicate xattr_ref */
+
+#define RAWNODE_CLASS_INODE_CACHE	0
+#define RAWNODE_CLASS_XATTR_DATUM	1
+#define RAWNODE_CLASS_XATTR_REF		2
+
 #define INOCACHE_HASHSIZE 128
 
 /*
@@ -374,6 +387,12 @@ struct jffs2_node_frag *jffs2_alloc_node_frag(void);
 void jffs2_free_node_frag(struct jffs2_node_frag *);
 struct jffs2_inode_cache *jffs2_alloc_inode_cache(void);
 void jffs2_free_inode_cache(struct jffs2_inode_cache *);
+#ifdef CONFIG_JFFS2_FS_XATTR
+struct jffs2_xattr_datum *jffs2_alloc_xattr_datum(void);
+void jffs2_free_xattr_datum(struct jffs2_xattr_datum *);
+struct jffs2_xattr_ref *jffs2_alloc_xattr_ref(void);
+void jffs2_free_xattr_ref(struct jffs2_xattr_ref *);
+#endif
 
 /* gc.c */
 int jffs2_garbage_collect_pass(struct jffs2_sb_info *c);