1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef _UAPI_FALLOC_H_ 3 #define _UAPI_FALLOC_H_ 4 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 /* 10 * FALLOC_FL_COLLAPSE_RANGE is used to remove a range of a file 11 * without leaving a hole in the file. The contents of the file beyond 12 * the range being removed is appended to the start offset of the range 13 * being removed (i.e. the hole that was punched is "collapsed"), 14 * resulting in a file layout that looks like the range that was 15 * removed never existed. As such collapsing a range of a file changes 16 * the size of the file, reducing it by the same length of the range 17 * that has been removed by the operation. 18 * 19 * Different filesystems may implement different limitations on the 20 * granularity of the operation. Most will limit operations to 21 * filesystem block size boundaries, but this boundary may be larger or 22 * smaller depending on the filesystem and/or the configuration of the 23 * filesystem or file. 24 * 25 * Attempting to collapse a range that crosses the end of the file is 26 * considered an illegal operation - just use ftruncate(2) if you need 27 * to collapse a range that crosses EOF. 28 */ 29 #define FALLOC_FL_COLLAPSE_RANGE 0x08 30 31 /* 32 * FALLOC_FL_ZERO_RANGE is used to convert a range of file to zeros preferably 33 * without issuing data IO. Blocks should be preallocated for the regions that 34 * span holes in the file, and the entire range is preferable converted to 35 * unwritten extents - even though file system may choose to zero out the 36 * extent or do whatever which will result in reading zeros from the range 37 * while the range remains allocated for the file. 38 * 39 * This can be also used to preallocate blocks past EOF in the same way as 40 * with fallocate. Flag FALLOC_FL_KEEP_SIZE should cause the inode 41 * size to remain the same. 42 */ 43 #define FALLOC_FL_ZERO_RANGE 0x10 44 45 /* 46 * FALLOC_FL_INSERT_RANGE is use to insert space within the file size without 47 * overwriting any existing data. The contents of the file beyond offset are 48 * shifted towards right by len bytes to create a hole. As such, this 49 * operation will increase the size of the file by len bytes. 50 * 51 * Different filesystems may implement different limitations on the granularity 52 * of the operation. Most will limit operations to filesystem block size 53 * boundaries, but this boundary may be larger or smaller depending on 54 * the filesystem and/or the configuration of the filesystem or file. 55 * 56 * Attempting to insert space using this flag at OR beyond the end of 57 * the file is considered an illegal operation - just use ftruncate(2) or 58 * fallocate(2) with mode 0 for such type of operations. 59 */ 60 #define FALLOC_FL_INSERT_RANGE 0x20 61 62 /* 63 * FALLOC_FL_UNSHARE_RANGE is used to unshare shared blocks within the 64 * file size without overwriting any existing data. The purpose of this 65 * call is to preemptively reallocate any blocks that are subject to 66 * copy-on-write. 67 * 68 * Different filesystems may implement different limitations on the 69 * granularity of the operation. Most will limit operations to filesystem 70 * block size boundaries, but this boundary may be larger or smaller 71 * depending on the filesystem and/or the configuration of the filesystem 72 * or file. 73 * 74 * This flag can only be used with allocate-mode fallocate, which is 75 * to say that it cannot be used with the punch, zero, collapse, or 76 * insert range modes. 77 */ 78 #define FALLOC_FL_UNSHARE_RANGE 0x40 79 80 #endif /* _UAPI_FALLOC_H_ */ 81