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oasis-root

Compiled tree of Oasis Linux based on own branch at <https://hacktivis.me/git/oasis/> git clone https://anongit.hacktivis.me/git/oasis-root.git

falloc.h (3643B)


  1. /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
  2. #ifndef _FALLOC_H_
  3. #define _FALLOC_H_
  4. #define FALLOC_FL_ALLOCATE_RANGE 0x00 /* allocate range */
  5. #define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */
  6. #define FALLOC_FL_PUNCH_HOLE 0x02 /* de-allocates range */
  7. #define FALLOC_FL_NO_HIDE_STALE 0x04 /* reserved codepoint */
  8. /*
  9. * FALLOC_FL_COLLAPSE_RANGE is used to remove a range of a file
  10. * without leaving a hole in the file. The contents of the file beyond
  11. * the range being removed is appended to the start offset of the range
  12. * being removed (i.e. the hole that was punched is "collapsed"),
  13. * resulting in a file layout that looks like the range that was
  14. * removed never existed. As such collapsing a range of a file changes
  15. * the size of the file, reducing it by the same length of the range
  16. * that has been removed by the operation.
  17. *
  18. * Different filesystems may implement different limitations on the
  19. * granularity of the operation. Most will limit operations to
  20. * filesystem block size boundaries, but this boundary may be larger or
  21. * smaller depending on the filesystem and/or the configuration of the
  22. * filesystem or file.
  23. *
  24. * Attempting to collapse a range that crosses the end of the file is
  25. * considered an illegal operation - just use ftruncate(2) if you need
  26. * to collapse a range that crosses EOF.
  27. */
  28. #define FALLOC_FL_COLLAPSE_RANGE 0x08
  29. /*
  30. * FALLOC_FL_ZERO_RANGE is used to convert a range of file to zeros preferably
  31. * without issuing data IO. Blocks should be preallocated for the regions that
  32. * span holes in the file, and the entire range is preferable converted to
  33. * unwritten extents - even though file system may choose to zero out the
  34. * extent or do whatever which will result in reading zeros from the range
  35. * while the range remains allocated for the file.
  36. *
  37. * This can be also used to preallocate blocks past EOF in the same way as
  38. * with fallocate. Flag FALLOC_FL_KEEP_SIZE should cause the inode
  39. * size to remain the same.
  40. */
  41. #define FALLOC_FL_ZERO_RANGE 0x10
  42. /*
  43. * FALLOC_FL_INSERT_RANGE is use to insert space within the file size without
  44. * overwriting any existing data. The contents of the file beyond offset are
  45. * shifted towards right by len bytes to create a hole. As such, this
  46. * operation will increase the size of the file by len bytes.
  47. *
  48. * Different filesystems may implement different limitations on the granularity
  49. * of the operation. Most will limit operations to filesystem block size
  50. * boundaries, but this boundary may be larger or smaller depending on
  51. * the filesystem and/or the configuration of the filesystem or file.
  52. *
  53. * Attempting to insert space using this flag at OR beyond the end of
  54. * the file is considered an illegal operation - just use ftruncate(2) or
  55. * fallocate(2) with mode 0 for such type of operations.
  56. */
  57. #define FALLOC_FL_INSERT_RANGE 0x20
  58. /*
  59. * FALLOC_FL_UNSHARE_RANGE is used to unshare shared blocks within the
  60. * file size without overwriting any existing data. The purpose of this
  61. * call is to preemptively reallocate any blocks that are subject to
  62. * copy-on-write.
  63. *
  64. * Different filesystems may implement different limitations on the
  65. * granularity of the operation. Most will limit operations to filesystem
  66. * block size boundaries, but this boundary may be larger or smaller
  67. * depending on the filesystem and/or the configuration of the filesystem
  68. * or file.
  69. *
  70. * This flag can only be used with allocate-mode fallocate, which is
  71. * to say that it cannot be used with the punch, zero, collapse, or
  72. * insert range modes.
  73. */
  74. #define FALLOC_FL_UNSHARE_RANGE 0x40
  75. #endif /* _FALLOC_H_ */