linux/fs/nilfs2/dat.h
Ryusuke Konishi 003ff182fd nilfs2: allow future expansion of metadata read out via get info ioctl
Nilfs has some ioctl commands to read out metadata from meta data
files:

 - NILFS_IOCTL_GET_CPINFO for checkpoint file,
 - NILFS_IOCTL_GET_SUINFO for segment usage file, and
 - NILFS_IOCTL_GET_VINFO for Disk Address Transalation (DAT) file,
   respectively.

Every routine on these metadata files is implemented so that it allows
future expansion of on-disk format.  But, the above ioctl commands do
not support expansion even though nilfs_argv structure can handle
arbitrary size for data exchanged via ioctl.

This allows future expansion of the following structures which give
basic format of the "get information" ioctls:

 - struct nilfs_cpinfo
 - struct nilfs_suinfo
 - struct nilfs_vinfo

So, this introduces forward compatility of such ioctl commands.

In this patch, a sanity check in nilfs_ioctl_get_info() function is
changed to accept larger data structure [1], and metadata read
routines are rewritten so that they become compatible for larger
structures; the routines will just ignore the remaining fields which
the current version of nilfs doesn't know.

[1] The ioctl function already has another upper limit (PAGE_SIZE
    against a structure, which appears in nilfs_ioctl_wrap_copy
    function), and this will not cause security problem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-06-10 23:41:11 +09:00

53 lines
2.0 KiB
C

/*
* dat.h - NILFS disk address translation.
*
* 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_DAT_H
#define _NILFS_DAT_H
#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#define NILFS_DAT_GFP NILFS_MDT_GFP
struct nilfs_palloc_req;
int nilfs_dat_translate(struct inode *, __u64, sector_t *);
int nilfs_dat_prepare_alloc(struct inode *, struct nilfs_palloc_req *);
void nilfs_dat_commit_alloc(struct inode *, struct nilfs_palloc_req *);
void nilfs_dat_abort_alloc(struct inode *, struct nilfs_palloc_req *);
int nilfs_dat_prepare_start(struct inode *, struct nilfs_palloc_req *);
void nilfs_dat_commit_start(struct inode *, struct nilfs_palloc_req *,
sector_t);
void nilfs_dat_abort_start(struct inode *, struct nilfs_palloc_req *);
int nilfs_dat_prepare_end(struct inode *, struct nilfs_palloc_req *);
void nilfs_dat_commit_end(struct inode *, struct nilfs_palloc_req *, int);
void nilfs_dat_abort_end(struct inode *, struct nilfs_palloc_req *);
int nilfs_dat_mark_dirty(struct inode *, __u64);
int nilfs_dat_freev(struct inode *, __u64 *, size_t);
int nilfs_dat_move(struct inode *, __u64, sector_t);
ssize_t nilfs_dat_get_vinfo(struct inode *, void *, unsigned, size_t);
#endif /* _NILFS_DAT_H */