bmap.h

Go to the documentation of this file.

/*
 * bmap.h - NILFS block mapping.
 *
 * 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 <[email protected]>.
 */

#ifndef _NILFS_BMAP_H
#define _NILFS_BMAP_H

#include <linux/types.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/nilfs2_fs.h>
#include "alloc.h"
#include "dat.h"

#define NILFS_BMAP_INVALID_PTR  0

#define nilfs_bmap_keydiff_abs(diff)    ((diff) < 0 ? -(diff) : (diff))


struct nilfs_bmap;

union nilfs_bmap_ptr_req {
    __u64 bpr_ptr;
    struct nilfs_palloc_req bpr_req;
};

struct nilfs_bmap_stats {
    unsigned int bs_nblocks;
};

struct nilfs_bmap_operations {
    int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);
    int (*bop_lookup_contig)(const struct nilfs_bmap *, __u64, __u64 *,
                 unsigned);
    int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
    int (*bop_delete)(struct nilfs_bmap *, __u64);
    void (*bop_clear)(struct nilfs_bmap *);

    int (*bop_propagate)(struct nilfs_bmap *, struct buffer_head *);
    void (*bop_lookup_dirty_buffers)(struct nilfs_bmap *,
                     struct list_head *);

    int (*bop_assign)(struct nilfs_bmap *,
              struct buffer_head **,
              sector_t,
              union nilfs_binfo *);
    int (*bop_mark)(struct nilfs_bmap *, __u64, int);

    /* The following functions are internal use only. */
    int (*bop_last_key)(const struct nilfs_bmap *, __u64 *);
    int (*bop_check_insert)(const struct nilfs_bmap *, __u64);
    int (*bop_check_delete)(struct nilfs_bmap *, __u64);
    int (*bop_gather_data)(struct nilfs_bmap *, __u64 *, __u64 *, int);
};


#define NILFS_BMAP_SIZE     (NILFS_INODE_BMAP_SIZE * sizeof(__le64))
#define NILFS_BMAP_KEY_BIT  (sizeof(unsigned long) * 8 /* CHAR_BIT */)
#define NILFS_BMAP_NEW_PTR_INIT \
    (1UL << (sizeof(unsigned long) * 8 /* CHAR_BIT */ - 1))

static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
{
    return !!(ptr & NILFS_BMAP_NEW_PTR_INIT);
}


struct nilfs_bmap {
    union {
        __u8 u_flags;
        __le64 u_data[NILFS_BMAP_SIZE / sizeof(__le64)];
    } b_u;
    struct rw_semaphore b_sem;
    struct inode *b_inode;
    const struct nilfs_bmap_operations *b_ops;
    __u64 b_last_allocated_key;
    __u64 b_last_allocated_ptr;
    int b_ptr_type;
    int b_state;
    __u16 b_nchildren_per_block;
};

/* pointer type */
#define NILFS_BMAP_PTR_P    0   /* physical block number (i.e. LBN) */
#define NILFS_BMAP_PTR_VS   1   /* virtual block number (single
                       version) */
#define NILFS_BMAP_PTR_VM   2   /* virtual block number (has multiple
                       versions) */
#define NILFS_BMAP_PTR_U    (-1)    /* never perform pointer operations */

#define NILFS_BMAP_USE_VBN(bmap)    ((bmap)->b_ptr_type > 0)

/* state */
#define NILFS_BMAP_DIRTY    0x00000001

struct nilfs_bmap_store {
    __le64 data[NILFS_BMAP_SIZE / sizeof(__le64)];
    __u64 last_allocated_key;
    __u64 last_allocated_ptr;
    int state;
};

int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
int nilfs_bmap_last_key(struct nilfs_bmap *, unsigned long *);
int nilfs_bmap_truncate(struct nilfs_bmap *, unsigned long);
void nilfs_bmap_clear(struct nilfs_bmap *);
int nilfs_bmap_propagate(struct nilfs_bmap *, struct buffer_head *);
void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *, struct list_head *);
int nilfs_bmap_assign(struct nilfs_bmap *, struct buffer_head **,
              unsigned long, union nilfs_binfo *);
int nilfs_bmap_lookup_at_level(struct nilfs_bmap *, __u64, int, __u64 *);
int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);

void nilfs_bmap_init_gc(struct nilfs_bmap *);

void nilfs_bmap_save(const struct nilfs_bmap *, struct nilfs_bmap_store *);
void nilfs_bmap_restore(struct nilfs_bmap *, const struct nilfs_bmap_store *);

static inline int nilfs_bmap_lookup(struct nilfs_bmap *bmap, __u64 key,
                    __u64 *ptr)
{
    return nilfs_bmap_lookup_at_level(bmap, key, 1, ptr);
}

/*
 * Internal use only
 */
struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);

static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,
                           union nilfs_bmap_ptr_req *req,
                           struct inode *dat)
{
    if (dat)
        return nilfs_dat_prepare_alloc(dat, &req->bpr_req);
    /* ignore target ptr */
    req->bpr_ptr = bmap->b_last_allocated_ptr++;
    return 0;
}

static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,
                           union nilfs_bmap_ptr_req *req,
                           struct inode *dat)
{
    if (dat)
        nilfs_dat_commit_alloc(dat, &req->bpr_req);
}

static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,
                          union nilfs_bmap_ptr_req *req,
                          struct inode *dat)
{
    if (dat)
        nilfs_dat_abort_alloc(dat, &req->bpr_req);
    else
        bmap->b_last_allocated_ptr--;
}

static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,
                         union nilfs_bmap_ptr_req *req,
                         struct inode *dat)
{
    return dat ? nilfs_dat_prepare_end(dat, &req->bpr_req) : 0;
}

static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,
                         union nilfs_bmap_ptr_req *req,
                         struct inode *dat)
{
    if (dat)
        nilfs_dat_commit_end(dat, &req->bpr_req,
                     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
}

static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,
                        union nilfs_bmap_ptr_req *req,
                        struct inode *dat)
{
    if (dat)
        nilfs_dat_abort_end(dat, &req->bpr_req);
}

static inline void nilfs_bmap_set_target_v(struct nilfs_bmap *bmap, __u64 key,
                       __u64 ptr)
{
    bmap->b_last_allocated_key = key;
    bmap->b_last_allocated_ptr = ptr;
}

__u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
                  const struct buffer_head *);

__u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
__u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);


/* Assume that bmap semaphore is locked. */
static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
{
    return !!(bmap->b_state & NILFS_BMAP_DIRTY);
}

/* Assume that bmap semaphore is locked. */
static inline void nilfs_bmap_set_dirty(struct nilfs_bmap *bmap)
{
    bmap->b_state |= NILFS_BMAP_DIRTY;
}

/* Assume that bmap semaphore is locked. */
static inline void nilfs_bmap_clear_dirty(struct nilfs_bmap *bmap)
{
    bmap->b_state &= ~NILFS_BMAP_DIRTY;
}


#define NILFS_BMAP_LARGE    0x1

#define NILFS_BMAP_SMALL_LOW    NILFS_DIRECT_KEY_MIN
#define NILFS_BMAP_SMALL_HIGH   NILFS_DIRECT_KEY_MAX
#define NILFS_BMAP_LARGE_LOW    NILFS_BTREE_ROOT_NCHILDREN_MAX
#define NILFS_BMAP_LARGE_HIGH   NILFS_BTREE_KEY_MAX

#endif  /* _NILFS_BMAP_H */