fs: jffs2: add initial support for reading jffs2

Import the jffs2 filesystem code from Linux v5.5-rc1 and convert it
to work with barebox.

Writing is *not* supported.

Testing was done with a n25q256a-compatible QuadSPI chip on a
SoCFPGA-based Socrates board.

Testing was done with a combination of:
	user@somelinuxhost: mkfs.jffs2 --eraseblock=4 -d fs/jffs2/ -o jffs2.img
	root@target:~ flash_erase -j /dev/mtd5 0 0
	root@target:~ dd if=jffs2.img of=/dev/mtd5
	barebox@EBV SOCrates:/ mount /dev/mtd0.data
	(...)
	mounted /dev/mtd0.data on /mnt/mtd0.data

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 42 insertions, 0 deletions

diff --git a/fs/jffs2/acl.h b/fs/jffs2/acl.h
new file mode 100644
index 0000000000..12d0271bdd
--- /dev/null
+++ b/fs/jffs2/acl.h
@@ -0,0 +1,42 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2006  NEC Corporation
+ *
+ * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+struct jffs2_acl_entry {
+	jint16_t	e_tag;
+	jint16_t	e_perm;
+	jint32_t	e_id;
+};
+
+struct jffs2_acl_entry_short {
+	jint16_t	e_tag;
+	jint16_t	e_perm;
+};
+
+struct jffs2_acl_header {
+	jint32_t	a_version;
+	struct jffs2_acl_entry	a_entries[];
+};
+
+#ifdef CONFIG_JFFS2_FS_POSIX_ACL
+
+struct posix_acl *jffs2_get_acl(struct inode *inode, int type);
+int jffs2_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+extern int jffs2_init_acl_pre(struct inode *, struct inode *, umode_t *);
+extern int jffs2_init_acl_post(struct inode *);
+
+#else
+
+#define jffs2_get_acl				(NULL)
+#define jffs2_set_acl				(NULL)
+#define jffs2_init_acl_pre(dir_i,inode,mode)	(0)
+#define jffs2_init_acl_post(inode)		(0)
+
+#endif	/* CONFIG_JFFS2_FS_POSIX_ACL */