linux/fs/ntfs/runlist.h
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   1/*
   2 * runlist.h - Defines for runlist handling in NTFS Linux kernel driver.
   3 *             Part of the Linux-NTFS project.
   4 *
   5 * Copyright (c) 2001-2005 Anton Altaparmakov
   6 * Copyright (c) 2002 Richard Russon
   7 *
   8 * This program/include file is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as published
  10 * by the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program/include file is distributed in the hope that it will be
  14 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program (in the main directory of the Linux-NTFS
  20 * distribution in the file COPYING); if not, write to the Free Software
  21 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22 */
  23
  24#ifndef _LINUX_NTFS_RUNLIST_H
  25#define _LINUX_NTFS_RUNLIST_H
  26
  27#include "types.h"
  28#include "layout.h"
  29#include "volume.h"
  30
  31/**
  32 * runlist_element - in memory vcn to lcn mapping array element
  33 * @vcn:        starting vcn of the current array element
  34 * @lcn:        starting lcn of the current array element
  35 * @length:     length in clusters of the current array element
  36 *
  37 * The last vcn (in fact the last vcn + 1) is reached when length == 0.
  38 *
  39 * When lcn == -1 this means that the count vcns starting at vcn are not
  40 * physically allocated (i.e. this is a hole / data is sparse).
  41 */
  42typedef struct {        /* In memory vcn to lcn mapping structure element. */
  43        VCN vcn;        /* vcn = Starting virtual cluster number. */
  44        LCN lcn;        /* lcn = Starting logical cluster number. */
  45        s64 length;     /* Run length in clusters. */
  46} runlist_element;
  47
  48/**
  49 * runlist - in memory vcn to lcn mapping array including a read/write lock
  50 * @rl:         pointer to an array of runlist elements
  51 * @lock:       read/write spinlock for serializing access to @rl
  52 *
  53 */
  54typedef struct {
  55        runlist_element *rl;
  56        struct rw_semaphore lock;
  57} runlist;
  58
  59static inline void ntfs_init_runlist(runlist *rl)
  60{
  61        rl->rl = NULL;
  62        init_rwsem(&rl->lock);
  63}
  64
  65typedef enum {
  66        LCN_HOLE                = -1,   /* Keep this as highest value or die! */
  67        LCN_RL_NOT_MAPPED       = -2,
  68        LCN_ENOENT              = -3,
  69        LCN_ENOMEM              = -4,
  70        LCN_EIO                 = -5,
  71} LCN_SPECIAL_VALUES;
  72
  73extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
  74                runlist_element *srl);
  75
  76extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
  77                const ATTR_RECORD *attr, runlist_element *old_rl);
  78
  79extern LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn);
  80
  81#ifdef NTFS_RW
  82
  83extern runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl,
  84                const VCN vcn);
  85
  86extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
  87                const runlist_element *rl, const VCN first_vcn,
  88                const VCN last_vcn);
  89
  90extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
  91                const int dst_len, const runlist_element *rl,
  92                const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn);
  93
  94extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol,
  95                runlist *const runlist, const s64 new_length);
  96
  97int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
  98                const VCN start, const s64 length);
  99
 100#endif /* NTFS_RW */
 101
 102#endif /* _LINUX_NTFS_RUNLIST_H */
 103
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