nilfs2: meta data file

This adds the meta data file, which serves common buffer functions to the
DAT, sufile, cpfile, ifile, and so forth.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nilfs2/mdt.h

+/*
+ * mdt.h - NILFS meta data file prototype and definitions
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * 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 Ryusuke Konishi <ryusuke@osrg.net>
+ */
+
+#ifndef _NILFS_MDT_H
+#define _NILFS_MDT_H
+
+#include <linux/buffer_head.h>
+#include <linux/blockgroup_lock.h>
+#include "nilfs.h"
+#include "page.h"
+
+/**
+ * struct nilfs_mdt_info - on-memory private data of meta data files
+ * @mi_nilfs: back pointer to the_nilfs struct
+ * @mi_sem: reader/writer semaphore for meta data operations
+ * @mi_bgl: per-blockgroup locking
+ * @mi_entry_size: size of an entry
+ * @mi_first_entry_offset: offset to the first entry
+ * @mi_entries_per_block: number of entries in a block
+ * @mi_blocks_per_group: number of blocks in a group
+ * @mi_blocks_per_desc_block: number of blocks per descriptor block
+ */
+struct nilfs_mdt_info {
+	struct the_nilfs       *mi_nilfs;
+	struct rw_semaphore	mi_sem;
+	struct blockgroup_lock *mi_bgl;
+	unsigned		mi_entry_size;
+	unsigned		mi_first_entry_offset;
+	unsigned long		mi_entries_per_block;
+	unsigned long		mi_blocks_per_group;
+	unsigned long		mi_blocks_per_desc_block;
+};
+
+static inline struct nilfs_mdt_info *NILFS_MDT(const struct inode *inode)
+{
+	return inode->i_private;
+}
+
+static inline struct the_nilfs *NILFS_I_NILFS(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	return sb ? NILFS_SB(sb)->s_nilfs : NILFS_MDT(inode)->mi_nilfs;
+}
+
+/* Default GFP flags using highmem */
+#define NILFS_MDT_GFP      (__GFP_WAIT | __GFP_IO | __GFP_HIGHMEM)
+
+int nilfs_mdt_get_block(struct inode *, unsigned long, int,
+			void (*init_block)(struct inode *,
+					   struct buffer_head *, void *),
+			struct buffer_head **);
+int nilfs_mdt_delete_block(struct inode *, unsigned long);
+int nilfs_mdt_forget_block(struct inode *, unsigned long);
+int nilfs_mdt_mark_block_dirty(struct inode *, unsigned long);
+int nilfs_mdt_fetch_dirty(struct inode *);
+
+struct inode *nilfs_mdt_new(struct the_nilfs *, struct super_block *, ino_t,
+			    gfp_t);
+struct inode *nilfs_mdt_new_common(struct the_nilfs *, struct super_block *,
+				   ino_t, gfp_t);
+void nilfs_mdt_destroy(struct inode *);
+void nilfs_mdt_clear(struct inode *);
+void nilfs_mdt_set_entry_size(struct inode *, unsigned, unsigned);
+void nilfs_mdt_set_shadow(struct inode *, struct inode *);
+
+
+#define nilfs_mdt_mark_buffer_dirty(bh)	nilfs_mark_buffer_dirty(bh)
+
+static inline void nilfs_mdt_mark_dirty(struct inode *inode)
+{
+	if (!test_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state))
+		set_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state);
+}
+
+static inline void nilfs_mdt_clear_dirty(struct inode *inode)
+{
+	clear_bit(NILFS_I_DIRTY, &NILFS_I(inode)->i_state);
+}
+
+static inline __u64 nilfs_mdt_cno(struct inode *inode)
+{
+	return NILFS_MDT(inode)->mi_nilfs->ns_cno;
+}
+
+#define nilfs_mdt_bgl_lock(inode, bg) \
+	(&NILFS_MDT(inode)->mi_bgl->locks[(bg) & (NR_BG_LOCKS-1)].lock)
+
+
+static inline int
+nilfs_mdt_read_inode_direct(struct inode *inode, struct buffer_head *bh,
+			    unsigned n)
+{
+	return nilfs_read_inode_common(
+		inode, (struct nilfs_inode *)(bh->b_data + n));
+}
+
+static inline void
+nilfs_mdt_write_inode_direct(struct inode *inode, struct buffer_head *bh,
+			     unsigned n)
+{
+	nilfs_write_inode_common(
+		inode, (struct nilfs_inode *)(bh->b_data + n), 1);
+}
+
+#endif /* _NILFS_MDT_H */