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