alistair23-linux/fs/gfs2/bmap.h
Steven Whitehouse b50f227bdd GFS2: Clean up journal extent mapping
This patch fixes a long standing issue in mapping the journal
extents. Most journals will consist of only a single extent,
and although the cache took account of that by merging extents,
it did not actually map large extents, but instead was doing a
block by block mapping. Since the journal was only being mapped
on mount, this was not normally noticeable.

With the updated code, it is now possible to use the same extent
mapping system during journal recovery (which will be added in a
later patch). This will allow checking of the integrity of the
journal before any reply of the journal content is attempted. For
this reason the code is moving to bmap.c, since it will be used
more widely in due course.

An exercise left for the reader is to compare the new function
gfs2_map_journal_extents() with gfs2_write_alloc_required()

Additionally, should there be a failure, the error reporting is
also updated to show more detail about what went wrong.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-03-03 13:50:12 +00:00

62 lines
2 KiB
C

/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#ifndef __BMAP_DOT_H__
#define __BMAP_DOT_H__
#include "inode.h"
struct inode;
struct gfs2_inode;
struct page;
/**
* gfs2_write_calc_reserv - calculate number of blocks needed to write to a file
* @ip: the file
* @len: the number of bytes to be written to the file
* @data_blocks: returns the number of data blocks required
* @ind_blocks: returns the number of indirect blocks required
*
*/
static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
unsigned int len,
unsigned int *data_blocks,
unsigned int *ind_blocks)
{
const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
unsigned int tmp;
BUG_ON(gfs2_is_dir(ip));
*data_blocks = (len >> sdp->sd_sb.sb_bsize_shift) + 3;
*ind_blocks = 3 * (sdp->sd_max_height - 1);
for (tmp = *data_blocks; tmp > sdp->sd_diptrs;) {
tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
*ind_blocks += tmp;
}
}
extern int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
extern int gfs2_block_map(struct inode *inode, sector_t lblock,
struct buffer_head *bh, int create);
extern int gfs2_extent_map(struct inode *inode, u64 lblock, int *new,
u64 *dblock, unsigned *extlen);
extern int gfs2_setattr_size(struct inode *inode, u64 size);
extern void gfs2_trim_blocks(struct inode *inode);
extern int gfs2_truncatei_resume(struct gfs2_inode *ip);
extern int gfs2_file_dealloc(struct gfs2_inode *ip);
extern int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
unsigned int len);
extern int gfs2_map_journal_extents(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd);
extern void gfs2_free_journal_extents(struct gfs2_jdesc *jd);
#endif /* __BMAP_DOT_H__ */