| 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 | |
| 30 | #endif /* _UAPI_FALLOC_H_ */ |