lcnalloc.h 5.7 KB

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  1. /*
  2. * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation. Part of the
  3. * Linux-NTFS project.
  4. *
  5. * Copyright (c) 2004-2005 Anton Altaparmakov
  6. *
  7. * This program/include file is free software; you can redistribute it and/or
  8. * modify it under the terms of the GNU General Public License as published
  9. * by the Free Software Foundation; either version 2 of the License, or
  10. * (at your option) any later version.
  11. *
  12. * This program/include file is distributed in the hope that it will be
  13. * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  14. * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15. * GNU General Public License for more details.
  16. *
  17. * You should have received a copy of the GNU General Public License
  18. * along with this program (in the main directory of the Linux-NTFS
  19. * distribution in the file COPYING); if not, write to the Free Software
  20. * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21. */
  22. #ifndef _LINUX_NTFS_LCNALLOC_H
  23. #define _LINUX_NTFS_LCNALLOC_H
  24. #ifdef NTFS_RW
  25. #include <linux/fs.h>
  26. #include "attrib.h"
  27. #include "types.h"
  28. #include "inode.h"
  29. #include "runlist.h"
  30. #include "volume.h"
  31. typedef enum {
  32. FIRST_ZONE = 0, /* For sanity checking. */
  33. MFT_ZONE = 0, /* Allocate from $MFT zone. */
  34. DATA_ZONE = 1, /* Allocate from $DATA zone. */
  35. LAST_ZONE = 1, /* For sanity checking. */
  36. } NTFS_CLUSTER_ALLOCATION_ZONES;
  37. extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
  38. const VCN start_vcn, const s64 count, const LCN start_lcn,
  39. const NTFS_CLUSTER_ALLOCATION_ZONES zone,
  40. const bool is_extension);
  41. extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
  42. s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);
  43. /**
  44. * ntfs_cluster_free - free clusters on an ntfs volume
  45. * @ni: ntfs inode whose runlist describes the clusters to free
  46. * @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
  47. * @count: number of clusters to free or -1 for all clusters
  48. * @ctx: active attribute search context if present or NULL if not
  49. *
  50. * Free @count clusters starting at the cluster @start_vcn in the runlist
  51. * described by the ntfs inode @ni.
  52. *
  53. * If @count is -1, all clusters from @start_vcn to the end of the runlist are
  54. * deallocated. Thus, to completely free all clusters in a runlist, use
  55. * @start_vcn = 0 and @count = -1.
  56. *
  57. * If @ctx is specified, it is an active search context of @ni and its base mft
  58. * record. This is needed when ntfs_cluster_free() encounters unmapped runlist
  59. * fragments and allows their mapping. If you do not have the mft record
  60. * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
  61. * the necessary mapping and unmapping.
  62. *
  63. * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
  64. * before returning. Thus, @ctx will be left pointing to the same attribute on
  65. * return as on entry. However, the actual pointers in @ctx may point to
  66. * different memory locations on return, so you must remember to reset any
  67. * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
  68. * you will probably want to do:
  69. * m = ctx->mrec;
  70. * a = ctx->attr;
  71. * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
  72. * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
  73. *
  74. * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
  75. * from the runlist or mark sparse the freed runs later.
  76. *
  77. * Return the number of deallocated clusters (not counting sparse ones) on
  78. * success and -errno on error.
  79. *
  80. * WARNING: If @ctx is supplied, regardless of whether success or failure is
  81. * returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
  82. * is no longer valid, i.e. you need to either call
  83. * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
  84. * In that case PTR_ERR(@ctx->mrec) will give you the error code for
  85. * why the mapping of the old inode failed.
  86. *
  87. * Locking: - The runlist described by @ni must be locked for writing on entry
  88. * and is locked on return. Note the runlist may be modified when
  89. * needed runlist fragments need to be mapped.
  90. * - The volume lcn bitmap must be unlocked on entry and is unlocked
  91. * on return.
  92. * - This function takes the volume lcn bitmap lock for writing and
  93. * modifies the bitmap contents.
  94. * - If @ctx is NULL, the base mft record of @ni must not be mapped on
  95. * entry and it will be left unmapped on return.
  96. * - If @ctx is not NULL, the base mft record must be mapped on entry
  97. * and it will be left mapped on return.
  98. */
  99. static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
  100. s64 count, ntfs_attr_search_ctx *ctx)
  101. {
  102. return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);
  103. }
  104. extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
  105. const runlist_element *rl);
  106. /**
  107. * ntfs_cluster_free_from_rl - free clusters from runlist
  108. * @vol: mounted ntfs volume on which to free the clusters
  109. * @rl: runlist describing the clusters to free
  110. *
  111. * Free all the clusters described by the runlist @rl on the volume @vol. In
  112. * the case of an error being returned, at least some of the clusters were not
  113. * freed.
  114. *
  115. * Return 0 on success and -errno on error.
  116. *
  117. * Locking: - This function takes the volume lcn bitmap lock for writing and
  118. * modifies the bitmap contents.
  119. * - The caller must have locked the runlist @rl for reading or
  120. * writing.
  121. */
  122. static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
  123. const runlist_element *rl)
  124. {
  125. int ret;
  126. down_write(&vol->lcnbmp_lock);
  127. ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
  128. up_write(&vol->lcnbmp_lock);
  129. return ret;
  130. }
  131. #endif /* NTFS_RW */
  132. #endif /* defined _LINUX_NTFS_LCNALLOC_H */