[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>

1 files changed, 120 insertions, 0 deletions

diff --git a/fs/jffs2/xattr.h b/fs/jffs2/xattr.h
new file mode 100644
index 000000000000..d157ad641ed4
--- /dev/null
+++ b/fs/jffs2/xattr.h
@@ -0,0 +1,120 @@
+/*-------------------------------------------------------------------------*
+ *  File: fs/jffs2/xattr.c
+ *  XATTR support on JFFS2 FileSystem
+ *
+ *  Implemented by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *  Copyright (C) 2006 NEC Corporation
+ *
+ *  For licensing information, see the file 'LICENCE' in the jffs2 directory.
+ *-------------------------------------------------------------------------*/
+
+#ifndef _JFFS2_FS_XATTR_H_
+#define _JFFS2_FS_XATTR_H_
+
+#include <linux/xattr.h>
+
+#define JFFS2_XFLAGS_HOT	(0x01)	/* This datum is HOT */
+#define JFFS2_XFLAGS_BIND	(0x02)	/* This datum is not reclaimed */
+
+struct jffs2_xattr_datum
+{
+	void *always_null;
+	u8 class;
+	u8 flags;
+	u16 xprefix;			/* see JFFS2_XATTR_PREFIX_* */
+
+	struct jffs2_raw_node_ref *node;
+	struct list_head xindex;	/* chained from c->xattrindex[n] */
+	uint32_t refcnt;		/* # of xattr_ref refers this */
+	uint32_t xid;
+	uint32_t version;
+
+	uint32_t data_crc;
+	uint32_t hashkey;
+	char *xname;		/* XATTR name without prefix */
+	uint32_t name_len;	/* length of xname */
+	char *xvalue;		/* XATTR value */
+	uint32_t value_len;	/* length of xvalue */
+};
+
+struct jffs2_inode_cache;	/* forward refence */
+struct jffs2_xattr_ref
+{
+	void *always_null;
+	u8 class;
+	u8 flags;		/* Currently unused */
+	u16 unused;
+
+	struct jffs2_raw_node_ref *node;
+	union {
+		struct jffs2_inode_cache *ic;	/* reference to jffs2_inode_cache */
+		uint32_t ino;			/* only used in scanning/building  */
+	};
+	union {
+		struct jffs2_xattr_datum *xd;	/* reference to jffs2_xattr_datum */
+		uint32_t xid;			/* only used in sccanning/building */
+	};
+	struct list_head ilist;			/* chained from ic->ilist */
+};
+
+#ifdef CONFIG_JFFS2_FS_XATTR
+
+extern void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c);
+extern void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c);
+extern void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c);
+
+extern struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
+                                                  uint32_t xid, uint32_t version);
+
+extern void jffs2_xattr_delete_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic);
+extern void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic);
+
+extern int jffs2_garbage_collect_xattr(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic);
+extern int jffs2_verify_xattr(struct jffs2_sb_info *c);
+
+extern int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
+			     char *buffer, size_t size);
+extern int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
+			     const char *buffer, size_t size, int flags);
+
+extern struct xattr_handler *jffs2_xattr_handlers[];
+extern struct xattr_handler jffs2_user_xattr_handler;
+extern struct xattr_handler jffs2_trusted_xattr_handler;
+
+extern ssize_t jffs2_listxattr(struct dentry *, char *, size_t);
+#define jffs2_getxattr		generic_getxattr
+#define jffs2_setxattr		generic_setxattr
+#define jffs2_removexattr	generic_removexattr
+
+/*---- Any inline initialize functions ----*/
+#define init_xattr_inode_cache(x) INIT_LIST_HEAD(&((x)->ilist))
+
+#else
+
+#define jffs2_init_xattr_subsystem(c)
+#define jffs2_build_xattr_subsystem(c)
+#define jffs2_clear_xattr_subsystem(c)
+
+#define jffs2_xattr_delete_inode(c, ic)
+#define jffs2_xattr_free_inode(c, ic)
+#define jffs2_garbage_collect_xattr(c, ic)	(1)
+#define jffs2_verify_xattr(c)			(1)
+
+#define jffs2_xattr_handlers	NULL
+#define jffs2_listxattr		NULL
+#define jffs2_getxattr		NULL
+#define jffs2_setxattr		NULL
+#define jffs2_removexattr	NULL
+
+#define init_xattr_inode_cache(x)
+
+#endif /* CONFIG_JFFS2_FS_XATTR */
+
+#ifdef CONFIG_JFFS2_FS_SECURITY
+extern int jffs2_init_security(struct inode *inode, struct inode *dir);
+extern struct xattr_handler jffs2_security_xattr_handler;
+#else
+#define jffs2_init_security(inode,dir)	(0)
+#endif /* CONFIG_JFFS2_FS_SECURITY */
+
+#endif /* _JFFS2_FS_XATTR_H_ */