linux/fs/nilfs2/sb.h
Ryusuke Konishi f11459ad7d nilfs2: do not allocate multiple super block instances for a device
This stops allocating multiple super block instances for a device.

All snapshots and a current mode mount (i.e. latest tree) will be
controlled with nilfs_root objects that are kept within an sb
instance.

nilfs_get_sb() is rewritten so that it always has a root object for
the latest tree and snapshots make additional root objects.

The root dentry of the latest tree is binded to sb->s_root even if it
isn't attached on a directory.  Root dentries of snapshots or the
latest tree are binded to mnt->mnt_root on which they are mounted.

With this patch, nilfs_find_sbinfo() function, nilfs->ns_supers list,
and nilfs->ns_current back pointer, are deleted.  In addition,
init_nilfs() and load_nilfs() are simplified since they will be called
once for a device, not repeatedly called for mount points.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:36 +09:00

93 lines
2.5 KiB
C

/*
* sb.h - NILFS on-memory super block structure.
*
* 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_SB
#define _NILFS_SB
#include <linux/types.h>
#include <linux/fs.h>
/*
* Mount options
*/
struct nilfs_mount_options {
unsigned long mount_opt;
__u64 snapshot_cno;
};
struct the_nilfs;
struct nilfs_sc_info;
/*
* NILFS super-block data in memory
*/
struct nilfs_sb_info {
/* Mount options */
unsigned long s_mount_opt;
uid_t s_resuid;
gid_t s_resgid;
unsigned long s_interval; /* construction interval */
unsigned long s_watermark; /* threshold of data amount
for the segment construction */
/* Fundamental members */
struct super_block *s_super; /* reverse pointer to super_block */
struct the_nilfs *s_nilfs;
/* Segment constructor */
struct list_head s_dirty_files; /* dirty files list */
struct nilfs_sc_info *s_sc_info; /* segment constructor info */
spinlock_t s_inode_lock; /* Lock for the nilfs inode.
It covers s_dirty_files list */
/* Inode allocator */
spinlock_t s_next_gen_lock;
u32 s_next_generation;
};
static inline struct nilfs_sb_info *NILFS_SB(struct super_block *sb)
{
return sb->s_fs_info;
}
static inline struct nilfs_sc_info *NILFS_SC(struct nilfs_sb_info *sbi)
{
return sbi->s_sc_info;
}
/*
* Bit operations for the mount option
*/
#define nilfs_clear_opt(sbi, opt) \
do { (sbi)->s_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
#define nilfs_set_opt(sbi, opt) \
do { (sbi)->s_mount_opt |= NILFS_MOUNT_##opt; } while (0)
#define nilfs_test_opt(sbi, opt) ((sbi)->s_mount_opt & NILFS_MOUNT_##opt)
#define nilfs_write_opt(sbi, mask, opt) \
do { (sbi)->s_mount_opt = \
(((sbi)->s_mount_opt & ~NILFS_MOUNT_##mask) | \
NILFS_MOUNT_##opt); \
} while (0)
#endif /* _NILFS_SB */