kernel-ark/fs/nilfs2/sufile.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

142 lines
4.6 KiB
C

/*
* 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_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 *);
ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, void *, unsigned,
size_t);
int nilfs_sufile_updatev(struct inode *, __u64 *, size_t, int, size_t *,
void (*dofunc)(struct inode *, __u64,
struct buffer_head *,
struct buffer_head *));
int nilfs_sufile_update(struct inode *, __u64, int,
void (*dofunc)(struct inode *, __u64,
struct buffer_head *,
struct buffer_head *));
void nilfs_sufile_do_scrap(struct inode *, __u64, struct buffer_head *,
struct buffer_head *);
void nilfs_sufile_do_free(struct inode *, __u64, struct buffer_head *,
struct buffer_head *);
void nilfs_sufile_do_cancel_free(struct inode *, __u64, struct buffer_head *,
struct buffer_head *);
void nilfs_sufile_do_set_error(struct inode *, __u64, struct buffer_head *,
struct buffer_head *);
/**
* nilfs_sufile_scrap - make a segment garbage
* @sufile: inode of segment usage file
* @segnum: segment number to be freed
*/
static inline int nilfs_sufile_scrap(struct inode *sufile, __u64 segnum)
{
return nilfs_sufile_update(sufile, segnum, 1, nilfs_sufile_do_scrap);
}
/**
* nilfs_sufile_free - free segment
* @sufile: inode of segment usage file
* @segnum: segment number to be freed
*/
static inline int nilfs_sufile_free(struct inode *sufile, __u64 segnum)
{
return nilfs_sufile_update(sufile, segnum, 0, nilfs_sufile_do_free);
}
/**
* nilfs_sufile_freev - free segments
* @sufile: inode of segment usage file
* @segnumv: array of segment numbers
* @nsegs: size of @segnumv array
* @ndone: place to store the number of freed segments
*/
static inline int nilfs_sufile_freev(struct inode *sufile, __u64 *segnumv,
size_t nsegs, size_t *ndone)
{
return nilfs_sufile_updatev(sufile, segnumv, nsegs, 0, ndone,
nilfs_sufile_do_free);
}
/**
* nilfs_sufile_cancel_freev - reallocate freeing segments
* @sufile: inode of segment usage file
* @segnumv: array of segment numbers
* @nsegs: size of @segnumv array
* @ndone: place to store the number of cancelled segments
*
* Return Value: On success, 0 is returned. On error, a negative error codes
* is returned.
*/
static inline int nilfs_sufile_cancel_freev(struct inode *sufile,
__u64 *segnumv, size_t nsegs,
size_t *ndone)
{
return nilfs_sufile_updatev(sufile, segnumv, nsegs, 0, ndone,
nilfs_sufile_do_cancel_free);
}
/**
* nilfs_sufile_set_error - mark a segment as erroneous
* @sufile: inode of segment usage file
* @segnum: segment number
*
* Description: nilfs_sufile_set_error() marks the segment specified by
* @segnum as erroneous. The error segment will never be used again.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-EINVAL - Invalid segment usage number.
*/
static inline int nilfs_sufile_set_error(struct inode *sufile, __u64 segnum)
{
return nilfs_sufile_update(sufile, segnum, 0,
nilfs_sufile_do_set_error);
}
#endif /* _NILFS_SUFILE_H */