f2fs: add xattr and acl functionalities

This implements xattr and acl functionalities.

- F2FS uses a node page to contain use extended attributes.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 145 insertions, 0 deletions

diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h
new file mode 100644
index 000000000000..29b0a08e1e14
--- /dev/null
+++ b/fs/f2fs/xattr.h
@@ -0,0 +1,145 @@
+/**
+ * fs/f2fs/xattr.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/xattr.h
+ *
+ * On-disk format of extended attributes for the ext2 filesystem.
+ *
+ * (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __F2FS_XATTR_H__
+#define __F2FS_XATTR_H__
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define F2FS_XATTR_MAGIC                0xF2F52011
+
+/* Maximum number of references to one attribute block */
+#define F2FS_XATTR_REFCOUNT_MAX         1024
+
+/* Name indexes */
+#define F2FS_SYSTEM_ADVISE_PREFIX               "system.advise"
+#define F2FS_XATTR_INDEX_USER                   1
+#define F2FS_XATTR_INDEX_POSIX_ACL_ACCESS       2
+#define F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT      3
+#define F2FS_XATTR_INDEX_TRUSTED                4
+#define F2FS_XATTR_INDEX_LUSTRE                 5
+#define F2FS_XATTR_INDEX_SECURITY               6
+#define F2FS_XATTR_INDEX_ADVISE                 7
+
+struct f2fs_xattr_header {
+        __le32  h_magic;        /* magic number for identification */
+        __le32  h_refcount;     /* reference count */
+        __u32   h_reserved[4];  /* zero right now */
+};
+
+struct f2fs_xattr_entry {
+        __u8    e_name_index;
+        __u8    e_name_len;
+        __le16  e_value_size;   /* size of attribute value */
+        char    e_name[0];      /* attribute name */
+};
+
+#define XATTR_HDR(ptr)          ((struct f2fs_xattr_header *)(ptr))
+#define XATTR_ENTRY(ptr)        ((struct f2fs_xattr_entry *)(ptr))
+#define XATTR_FIRST_ENTRY(ptr)  (XATTR_ENTRY(XATTR_HDR(ptr)+1))
+#define XATTR_ROUND             (3)
+
+#define XATTR_ALIGN(size)       ((size + XATTR_ROUND) & ~XATTR_ROUND)
+
+#define ENTRY_SIZE(entry) (XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + \
+                        entry->e_name_len + le16_to_cpu(entry->e_value_size)))
+
+#define XATTR_NEXT_ENTRY(entry) ((struct f2fs_xattr_entry *)((char *)(entry) +\
+                        ENTRY_SIZE(entry)))
+
+#define IS_XATTR_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define list_for_each_xattr(entry, addr) \
+                for (entry = XATTR_FIRST_ENTRY(addr);\
+                                !IS_XATTR_LAST_ENTRY(entry);\
+                                entry = XATTR_NEXT_ENTRY(entry))
+
+
+#define MIN_OFFSET      XATTR_ALIGN(PAGE_SIZE - \
+                        sizeof(struct node_footer) - \
+                        sizeof(__u32))
+
+#define MAX_VALUE_LEN   (MIN_OFFSET - sizeof(struct f2fs_xattr_header) - \
+                        sizeof(struct f2fs_xattr_entry))
+
+/**
+ * On-disk structure of f2fs_xattr
+ * We use only 1 block for xattr.
+ *
+ * +--------------------+
+ * | f2fs_xattr_header  |
+ * |                    |
+ * +--------------------+
+ * | f2fs_xattr_entry   |
+ * | .e_name_index = 1  |
+ * | .e_name_len = 3    |
+ * | .e_value_size = 14 |
+ * | .e_name = "foo"    |
+ * | "value_of_xattr"   |<- value_offs = e_name + e_name_len
+ * +--------------------+
+ * | f2fs_xattr_entry   |
+ * | .e_name_index = 4  |
+ * | .e_name = "bar"    |
+ * +--------------------+
+ * |                    |
+ * |        Free        |
+ * |                    |
+ * +--------------------+<- MIN_OFFSET
+ * |   node_footer      |
+ * | (nid, ino, offset) |
+ * +--------------------+
+ *
+ **/
+
+#ifdef CONFIG_F2FS_FS_XATTR
+extern const struct xattr_handler f2fs_xattr_user_handler;
+extern const struct xattr_handler f2fs_xattr_trusted_handler;
+extern const struct xattr_handler f2fs_xattr_acl_access_handler;
+extern const struct xattr_handler f2fs_xattr_acl_default_handler;
+extern const struct xattr_handler f2fs_xattr_advise_handler;
+
+extern const struct xattr_handler *f2fs_xattr_handlers[];
+
+extern int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
+                const void *value, size_t value_len);
+extern int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
+                void *buffer, size_t buffer_size);
+extern ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
+                size_t buffer_size);
+
+#else
+
+#define f2fs_xattr_handlers     NULL
+static inline int f2fs_setxattr(struct inode *inode, int name_index,
+        const char *name, const void *value, size_t value_len)
+{
+        return -EOPNOTSUPP;
+}
+static inline int f2fs_getxattr(struct inode *inode, int name_index,
+                const char *name, void *buffer, size_t buffer_size)
+{
+        return -EOPNOTSUPP;
+}
+static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
+                size_t buffer_size)
+{
+        return -EOPNOTSUPP;
+}
+#endif
+
+#endif /* __F2FS_XATTR_H__ */