nilfs2: another dat for garbage collection

/*

 * gcdat.c - NILFS shadow DAT inode for GC

 *

 * 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 Seiji Kihara <kihara@osrg.net>, Amagai Yoshiji <amagai@osrg.net>,

 *            and Ryusuke Konishi <ryusuke@osrg.net>.

 *

 */

#include <linux/buffer_head.h>

#include "nilfs.h"

#include "page.h"

#include "mdt.h"

int nilfs_init_gcdat_inode(struct the_nilfs *nilfs)

{

	struct inode *dat = nilfs->ns_dat, *gcdat = nilfs->ns_gc_dat;

	struct nilfs_inode_info *dii = NILFS_I(dat), *gii = NILFS_I(gcdat);

	int err;

	gcdat->i_state = 0;

	gcdat->i_blocks = dat->i_blocks;

	gii->i_flags = dii->i_flags;

	gii->i_state = dii->i_state | (1 << NILFS_I_GCDAT);

	gii->i_cno = 0;

	nilfs_bmap_init_gcdat(gii->i_bmap, dii->i_bmap);

	err = nilfs_copy_dirty_pages(gcdat->i_mapping, dat->i_mapping);

	if (unlikely(err))

		return err;

	return nilfs_copy_dirty_pages(&gii->i_btnode_cache,

				      &dii->i_btnode_cache);

}

void nilfs_commit_gcdat_inode(struct the_nilfs *nilfs)

{

	struct inode *dat = nilfs->ns_dat, *gcdat = nilfs->ns_gc_dat;

	struct nilfs_inode_info *dii = NILFS_I(dat), *gii = NILFS_I(gcdat);

	struct address_space *mapping = dat->i_mapping;

	struct address_space *gmapping = gcdat->i_mapping;

	down_write(&NILFS_MDT(dat)->mi_sem);

	dat->i_blocks = gcdat->i_blocks;

	dii->i_flags = gii->i_flags;

	dii->i_state = gii->i_state & ~(1 << NILFS_I_GCDAT);

	nilfs_bmap_commit_gcdat(gii->i_bmap, dii->i_bmap);

	nilfs_clear_dirty_pages(mapping);

	nilfs_copy_back_pages(mapping, gmapping);

	/* note: mdt dirty flags should be cleared by segctor. */

	nilfs_clear_dirty_pages(&dii->i_btnode_cache);

	nilfs_copy_back_pages(&dii->i_btnode_cache, &gii->i_btnode_cache);

	up_write(&NILFS_MDT(dat)->mi_sem);

}

void nilfs_clear_gcdat_inode(struct the_nilfs *nilfs)

{

	struct inode *gcdat = nilfs->ns_gc_dat;

	struct nilfs_inode_info *gii = NILFS_I(gcdat);

	gcdat->i_state = I_CLEAR;

	gii->i_flags = 0;

	truncate_inode_pages(gcdat->i_mapping, 0);

	truncate_inode_pages(&gii->i_btnode_cache, 0);

}