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 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 /* 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 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 61 #endif /* _UAPI_FALLOC_H_ */ 62
