fs/ntfs/runlist.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * runlist.h - Defines for runlist handling in NTFS Linux kernel driver.
   4  *             Part of the Linux-NTFS project.
   5  *
   6  * Copyright (c) 2001-2005 Anton Altaparmakov
   7  * Copyright (c) 2002 Richard Russon
   8  */
   9
  10 #ifndef _LINUX_NTFS_RUNLIST_H
  11 #define _LINUX_NTFS_RUNLIST_H
  12
  13 #include "types.h"
  14 #include "layout.h"
  15 #include "volume.h"
  16
  17 /**
  18  * runlist_element - in memory vcn to lcn mapping array element
  19  * @vcn:        starting vcn of the current array element
  20  * @lcn:        starting lcn of the current array element
  21  * @length:     length in clusters of the current array element
  22  *
  23  * The last vcn (in fact the last vcn + 1) is reached when length == 0.
  24  *
  25  * When lcn == -1 this means that the count vcns starting at vcn are not
  26  * physically allocated (i.e. this is a hole / data is sparse).
  27  */
  28 typedef struct {        /* In memory vcn to lcn mapping structure element. */
  29         VCN vcn;        /* vcn = Starting virtual cluster number. */
  30         LCN lcn;        /* lcn = Starting logical cluster number. */
  31         s64 length;     /* Run length in clusters. */
  32 } runlist_element;
  33
  34 /**
  35  * runlist - in memory vcn to lcn mapping array including a read/write lock
  36  * @rl:         pointer to an array of runlist elements
  37  * @lock:       read/write spinlock for serializing access to @rl
  38  *
  39  */
  40 typedef struct {
  41         runlist_element *rl;
  42         struct rw_semaphore lock;
  43 } runlist;
  44
  45 static inline void ntfs_init_runlist(runlist *rl)
  46 {
  47         rl->rl = NULL;
  48         init_rwsem(&rl->lock);
  49 }
  50
  51 typedef enum {
  52         LCN_HOLE                = -1,   /* Keep this as highest value or die! */
  53         LCN_RL_NOT_MAPPED       = -2,
  54         LCN_ENOENT              = -3,
  55         LCN_ENOMEM              = -4,
  56         LCN_EIO                 = -5,
  57 } LCN_SPECIAL_VALUES;
  58
  59 extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
  60                 runlist_element *srl);
  61
  62 extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
  63                 const ATTR_RECORD *attr, runlist_element *old_rl);
  64
  65 extern LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn);
  66
  67 #ifdef NTFS_RW
  68
  69 extern runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl,
  70                 const VCN vcn);
  71
  72 extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
  73                 const runlist_element *rl, const VCN first_vcn,
  74                 const VCN last_vcn);
  75
  76 extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
  77                 const int dst_len, const runlist_element *rl,
  78                 const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn);
  79
  80 extern int ntfs_rl_truncate_nolock(const ntfs_volume *vol,
  81                 runlist *const runlist, const s64 new_length);
  82
  83 int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
  84                 const VCN start, const s64 length);
  85
  86 #endif /* NTFS_RW */
  87
  88 #endif /* _LINUX_NTFS_RUNLIST_H */