root/fs/ntfs/runlist.h

INCLUDED FROM

DEFINITIONS

1. ntfs_init_runlist

/*
 * runlist.h - Defines for runlist handling in NTFS Linux kernel driver.
 *             Part of the Linux-NTFS project.
 *
 * Copyright (c) 2001-2005 Anton Altaparmakov
 * Copyright (c) 2002 Richard Russon
 *
 * This program/include file 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/include file 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 (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _LINUX_NTFS_RUNLIST_H
#define _LINUX_NTFS_RUNLIST_H

#include "types.h"
#include "layout.h"
#include "volume.h"

/**
 * runlist_element - in memory vcn to lcn mapping array element
 * @vcn:        starting vcn of the current array element
 * @lcn:        starting lcn of the current array element
 * @length:     length in clusters of the current array element
 *
 * The last vcn (in fact the last vcn + 1) is reached when length == 0.
 *
 * When lcn == -1 this means that the count vcns starting at vcn are not
 * physically allocated (i.e. this is a hole / data is sparse).
 */
typedef struct {        /* In memory vcn to lcn mapping structure element. */
        VCN vcn;        /* vcn = Starting virtual cluster number. */
        LCN lcn;        /* lcn = Starting logical cluster number. */
        s64 length;     /* Run length in clusters. */
} runlist_element;

/**
 * runlist - in memory vcn to lcn mapping array including a read/write lock
 * @rl:         pointer to an array of runlist elements
 * @lock:       read/write spinlock for serializing access to @rl
 *
 */
typedef struct {
        runlist_element *rl;
        struct rw_semaphore lock;
} runlist;

static inline void ntfs_init_runlist(runlist *rl)
{
        rl->rl = NULL;
        init_rwsem(&rl->lock);
}

typedef enum {
        LCN_HOLE                = -1,   /* Keep this as highest value or die! */
        LCN_RL_NOT_MAPPED       = -2,
        LCN_ENOENT              = -3,
        LCN_ENOMEM              = -4,
        LCN_EIO                 = -5,
} LCN_SPECIAL_VALUES;

extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
                runlist_element *srl);

extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
                const ATTR_RECORD *attr, runlist_element *old_rl);

extern LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn);

#ifdef NTFS_RW

extern runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl,
                const VCN vcn);

extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
                const runlist_element *rl, const VCN first_vcn,
                const VCN last_vcn);

extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
                const int dst_len, const runlist_element *rl,
                const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn);

extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol,
                runlist *const runlist, const s64 new_length);

int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
                const VCN start, const s64 length);

#endif /* NTFS_RW */

#endif /* _LINUX_NTFS_RUNLIST_H */