From: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
Subject: [RFC][STEP 1][PATCH v2 02/17] nilfs2: introduce xanode related declarations
This patch adds declaration of structures, macros and auxiliary
functions for xafile's xanodes.
Signed-off-by: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
CC: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
---
fs/nilfs2/xafile.h | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 139 insertions(+)
create mode 100644 fs/nilfs2/xafile.h
diff --git a/fs/nilfs2/xafile.h b/fs/nilfs2/xafile.h
new file mode 100644
index 0000000..28faa1f
--- /dev/null
+++ b/fs/nilfs2/xafile.h
@@ -0,0 +1,139 @@
+/*
+ * xafile.h - NILFS extended attributes file (xafile) declarations.
+ *
+ * Copyright (C) 2005-2013 Nippon Telegraph and Telephone Corporation.
+ * Copyright (C) 2013 Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Written by Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
+ */
+
+#ifndef _NILFS_XAFILE_H
+#define _NILFS_XAFILE_H
+
+#include <linux/xattr.h>
+
+/* Magic number of xafile node */
+#define NILFS_XANODE_MAGIC 0x5841 /* XA */
+
+/* Xanode types */
+#define NILFS_UNKNOWN_XANODE_TYPE 0
+/* Temporary, numbers from 1 till 6 are simply reserved */
+#define NILFS_XATTR_TREE_XANODE_TYPE 7
+#define NILFS_XANODE_TYPE_MASK 0x000F
+
+/* Xanode's flags */
+#define NILFS_XANODE_CRC32_FLAG 0x0010
+#define NILFS_INDEX_XANODE_FLAG 0x0020
+#define NILFS_XANODE_FLAG_MASK 0xFFF0
+
+/*
+ * struct nilfs_tree_xanode_header - header of dedicated xanode
+ * @magic: magic number for identification
+ * @flags: xanode's flags
+ * @height: node height in the tree
+ * @log_index_keys: log2(index keys max count)
+ * @entries: count of entries in xanode
+ * @checksum: CRC32 of node
+ * @index_keys: current count of index keys
+ * @parent_node: node ID of a parent node
+ */
+struct nilfs_tree_xanode_header {
+ __le16 magic;
+ __le16 flags;
+ u8 height;
+#define NILFS_XANODE_MIN_INDEX_KEYS 4
+ u8 log_index_keys;
+ __le16 entries;
+ __le32 checksum;
+ __le32 index_keys;
+ __le64 parent_node;
+} __packed;
+
+union nilfs_xanode_header {
+ struct {
+ __le16 magic;
+ __le16 flags;
+ } __packed base_hdr;
+ struct nilfs_tree_xanode_header tree_hdr;
+};
+
+/* Xanode related declarations */
+#define BH_DATA(bh) \
+ ((char *)(((struct buffer_head *)(bh))->b_data))
+#define BH_SIZE(bh) \
+ (((struct buffer_head *)(bh))->b_size)
+
+#define NILFS_XANODE_BEGIN(bh) \
+ BH_DATA(bh)
+#define NILFS_XANODE_END(bh) \
+ (BH_DATA(bh) + BH_SIZE(bh))
+#define NILFS_XANODE_HDR(hdr_ptr) \
+ ((union nilfs_xanode_header *)(hdr_ptr))
+
+/* TODO: [REWORK] Temporary xanode size is fixed by 4 KB */
+#define NILFS_XANODE_SIZE PAGE_CACHE_SIZE
+
+#define NILFS_XANODE_HDR_SIZE_MAX 32
+#define NILFS_XANODE_INDEX_KEY_SIZE_MAX 16
+#define NILFS_XANODE_LEAF_KEY_SIZE_MAX 32
+
+#define NILFS_XATTR_VALUE_LEN_MAX \
+ (NILFS_XANODE_SIZE - \
+ (NILFS_XANODE_HDR_SIZE_MAX + \
+ (NILFS_XANODE_MIN_INDEX_KEYS * NILFS_XANODE_INDEX_KEY_SIZE_MAX) + \
+ NILFS_XANODE_LEAF_KEY_SIZE_MAX + \
+ (XATTR_NAME_MAX + 1)))
+
+#define NILFS_XANODE_TYPE(hdr_ptr) \
+ (le16_to_cpu(NILFS_XANODE_HDR(hdr_ptr)->base_hdr.flags) & \
+ NILFS_XANODE_TYPE_MASK)
+#define NILFS_XANODE_FLAGS(hdr_ptr) \
+ (le16_to_cpu(NILFS_XANODE_HDR(hdr_ptr)->base_hdr.flags) & \
+ NILFS_XANODE_FLAG_MASK)
+#define NILFS_XANODE_SET_TYPE(type, hdr_ptr) \
+ (cpu_to_le16(NILFS_XANODE_FLAGS(hdr_ptr) | \
+ ((u16)type & NILFS_XANODE_TYPE_MASK)))
+#define NILFS_XANODE_SET_FLAGS(flags, hdr_ptr) \
+ (cpu_to_le16((u16)flags | NILFS_XANODE_TYPE(hdr_ptr)))
+
+static inline
+size_t NILFS_XANODE_HDR_SIZE(union nilfs_xanode_header *hdr_ptr)
+{
+ switch (NILFS_XANODE_TYPE(hdr_ptr)) {
+ case NILFS_XATTR_TREE_XANODE_TYPE:
+ return sizeof(struct nilfs_tree_xanode_header);
+ };
+ BUG();
+}
+
+#define NILFS_XANODE_ENTRIES(hdr_ptr) \
+ (NILFS_XANODE_TYPE(hdr_ptr) == NILFS_XATTR_TREE_XANODE_TYPE ? \
+ le16_to_cpu(NILFS_XANODE_HDR(hdr_ptr)->tree_hdr.entries) : \
+ 0)
+
+static inline
+void NILFS_XANODE_ADD_ENTRIES(__u16 val, union nilfs_xanode_header *hdr_ptr)
+{
+ switch (NILFS_XANODE_TYPE(hdr_ptr)) {
+ case NILFS_XATTR_TREE_XANODE_TYPE:
+ le16_add_cpu(&hdr_ptr->tree_hdr.entries, val);
+ return;
+ };
+ BUG();
+}
+
+#endif /* _NILFS_XAFILE_H */
--
1.7.9.5
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