David Howells | 607ca46 | 2012-10-13 10:46:48 +0100 | [diff] [blame] | 1 | #ifndef _UAPI_FALLOC_H_ |
| 2 | #define _UAPI_FALLOC_H_ |
| 3 | |
| 4 | #define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */ |
| 5 | #define FALLOC_FL_PUNCH_HOLE 0x02 /* de-allocates range */ |
| 6 | #define FALLOC_FL_NO_HIDE_STALE 0x04 /* reserved codepoint */ |
| 7 | |
Namjae Jeon | 00f5e61 | 2014-02-24 10:58:15 +1100 | [diff] [blame] | 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 |
David Howells | 607ca46 | 2012-10-13 10:46:48 +0100 | [diff] [blame] | 29 | |
Lukas Czerner | 409332b | 2014-03-13 19:07:42 +1100 | [diff] [blame] | 30 | /* |
| 31 | * FALLOC_FL_ZERO_RANGE is used to convert a range of file to zeros preferably |
| 32 | * without issuing data IO. Blocks should be preallocated for the regions that |
| 33 | * span holes in the file, and the entire range is preferable converted to |
| 34 | * unwritten extents - even though file system may choose to zero out the |
| 35 | * extent or do whatever which will result in reading zeros from the range |
| 36 | * while the range remains allocated for the file. |
| 37 | * |
| 38 | * This can be also used to preallocate blocks past EOF in the same way as |
| 39 | * with fallocate. Flag FALLOC_FL_KEEP_SIZE should cause the inode |
| 40 | * size to remain the same. |
| 41 | */ |
| 42 | #define FALLOC_FL_ZERO_RANGE 0x10 |
| 43 | |
Namjae Jeon | dd46c78 | 2015-03-25 15:07:05 +1100 | [diff] [blame] | 44 | /* |
| 45 | * FALLOC_FL_INSERT_RANGE is use to insert space within the file size without |
| 46 | * overwriting any existing data. The contents of the file beyond offset are |
| 47 | * shifted towards right by len bytes to create a hole. As such, this |
| 48 | * operation will increase the size of the file by len bytes. |
| 49 | * |
| 50 | * Different filesystems may implement different limitations on the granularity |
| 51 | * of the operation. Most will limit operations to filesystem block size |
| 52 | * boundaries, but this boundary may be larger or smaller depending on |
| 53 | * the filesystem and/or the configuration of the filesystem or file. |
| 54 | * |
| 55 | * Attempting to insert space using this flag at OR beyond the end of |
| 56 | * the file is considered an illegal operation - just use ftruncate(2) or |
| 57 | * fallocate(2) with mode 0 for such type of operations. |
| 58 | */ |
| 59 | #define FALLOC_FL_INSERT_RANGE 0x20 |
| 60 | |
Darrick J. Wong | 71be6b4 | 2016-10-03 09:11:14 -0700 | [diff] [blame] | 61 | /* |
| 62 | * FALLOC_FL_UNSHARE_RANGE is used to unshare shared blocks within the |
| 63 | * file size without overwriting any existing data. The purpose of this |
| 64 | * call is to preemptively reallocate any blocks that are subject to |
| 65 | * copy-on-write. |
| 66 | * |
| 67 | * Different filesystems may implement different limitations on the |
| 68 | * granularity of the operation. Most will limit operations to filesystem |
| 69 | * block size boundaries, but this boundary may be larger or smaller |
| 70 | * depending on the filesystem and/or the configuration of the filesystem |
| 71 | * or file. |
| 72 | * |
| 73 | * This flag can only be used with allocate-mode fallocate, which is |
| 74 | * to say that it cannot be used with the punch, zero, collapse, or |
| 75 | * insert range modes. |
| 76 | */ |
| 77 | #define FALLOC_FL_UNSHARE_RANGE 0x40 |
| 78 | |
David Howells | 607ca46 | 2012-10-13 10:46:48 +0100 | [diff] [blame] | 79 | #endif /* _UAPI_FALLOC_H_ */ |