fs/ntfs/runlist.h

   1 /*
   2  * runlist.h - Defines for runlist handling in NTFS Linux kernel driver.
   3  *             Part of the Linux-NTFS project.
   4  *
   5  * Copyright (c) 2001-2004 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  */
  42 typedef 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  */
  54 typedef struct {
  55         runlist_element *rl;
  56         struct rw_semaphore lock;
  57 } runlist;
  58
  59 static inline void ntfs_init_runlist(runlist *rl)
  60 {
  61         rl->rl = NULL;
  62         init_rwsem(&rl->lock);
  63 }
  64
  65 typedef enum {
  66         LCN_HOLE                = -1,   /* Keep this as highest value or die! */
  67         LCN_RL_NOT_MAPPED       = -2,
  68         LCN_ENOENT              = -3,
  69 } LCN_SPECIAL_VALUES;
  70
  71 extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
  72                 runlist_element *srl);
  73
  74 extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
  75                 const ATTR_RECORD *attr, runlist_element *old_rl);
  76
  77 extern LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn);
  78
  79 extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
  80                 const runlist_element *rl, const VCN start_vcn);
  81
  82 extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
  83                 const int dst_len, const runlist_element *rl,
  84                 const VCN start_vcn, VCN *const stop_vcn);
  85
  86 extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol,
  87                 runlist *const runlist, const s64 new_length);
  88
  89 #endif /* _LINUX_NTFS_RUNLIST_H */