nilfs2: segment usage file

This adds a meta data file which stores the allocation state of segments.

[konishi.ryusuke@lab.ntt.co.jp: fix wrong counting of checkpoints and dirty segments]
Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
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/cpfile.c

@@ -357,7 +357,7 @@ int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
 		kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 		header = nilfs_cpfile_block_get_header(cpfile, header_bh,
 						       kaddr);
-		le64_add_cpu(&header->ch_ncheckpoints, -tnicps);
+		le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
 		nilfs_mdt_mark_buffer_dirty(header_bh);
 		nilfs_mdt_mark_dirty(cpfile);
 		kunmap_atomic(kaddr, KM_USER0);

fs/nilfs2/sufile.h

+/*
+ * sufile.h - NILFS segment usage file.
+ *
+ * Copyright (C) 2006-2008 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 Koji Sato <koji@osrg.net>.
+ */
+
+#ifndef _NILFS_SUFILE_H
+#define _NILFS_SUFILE_H
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/nilfs2_fs.h>
+#include "mdt.h"
+
+#define NILFS_SUFILE_GFP	NILFS_MDT_GFP
+
+static inline unsigned long nilfs_sufile_get_nsegments(struct inode *sufile)
+{
+	return NILFS_MDT(sufile)->mi_nilfs->ns_nsegments;
+}
+
+int nilfs_sufile_alloc(struct inode *, __u64 *);
+int nilfs_sufile_cancel_free(struct inode *, __u64);
+int nilfs_sufile_freev(struct inode *, __u64 *, size_t);
+int nilfs_sufile_free(struct inode *, __u64);
+int nilfs_sufile_get_segment_usage(struct inode *, __u64,
+				   struct nilfs_segment_usage **,
+				   struct buffer_head **);
+void nilfs_sufile_put_segment_usage(struct inode *, __u64,
+				    struct buffer_head *);
+int nilfs_sufile_get_stat(struct inode *, struct nilfs_sustat *);
+int nilfs_sufile_get_ncleansegs(struct inode *, unsigned long *);
+int nilfs_sufile_set_error(struct inode *, __u64);
+ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, struct nilfs_suinfo *,
+				size_t);
+
+
+#endif	/* _NILFS_SUFILE_H */