81 lines
3.5 KiB
C
81 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
|
#ifndef _UAPI_FALLOC_H_
|
|
#define _UAPI_FALLOC_H_
|
|
|
|
#define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */
|
|
#define FALLOC_FL_PUNCH_HOLE 0x02 /* de-allocates range */
|
|
#define FALLOC_FL_NO_HIDE_STALE 0x04 /* reserved codepoint */
|
|
|
|
/*
|
|
* FALLOC_FL_COLLAPSE_RANGE is used to remove a range of a file
|
|
* without leaving a hole in the file. The contents of the file beyond
|
|
* the range being removed is appended to the start offset of the range
|
|
* being removed (i.e. the hole that was punched is "collapsed"),
|
|
* resulting in a file layout that looks like the range that was
|
|
* removed never existed. As such collapsing a range of a file changes
|
|
* the size of the file, reducing it by the same length of the range
|
|
* that has been removed by the operation.
|
|
*
|
|
* Different filesystems may implement different limitations on the
|
|
* granularity of the operation. Most will limit operations to
|
|
* filesystem block size boundaries, but this boundary may be larger or
|
|
* smaller depending on the filesystem and/or the configuration of the
|
|
* filesystem or file.
|
|
*
|
|
* Attempting to collapse a range that crosses the end of the file is
|
|
* considered an illegal operation - just use ftruncate(2) if you need
|
|
* to collapse a range that crosses EOF.
|
|
*/
|
|
#define FALLOC_FL_COLLAPSE_RANGE 0x08
|
|
|
|
/*
|
|
* FALLOC_FL_ZERO_RANGE is used to convert a range of file to zeros preferably
|
|
* without issuing data IO. Blocks should be preallocated for the regions that
|
|
* span holes in the file, and the entire range is preferable converted to
|
|
* unwritten extents - even though file system may choose to zero out the
|
|
* extent or do whatever which will result in reading zeros from the range
|
|
* while the range remains allocated for the file.
|
|
*
|
|
* This can be also used to preallocate blocks past EOF in the same way as
|
|
* with fallocate. Flag FALLOC_FL_KEEP_SIZE should cause the inode
|
|
* size to remain the same.
|
|
*/
|
|
#define FALLOC_FL_ZERO_RANGE 0x10
|
|
|
|
/*
|
|
* FALLOC_FL_INSERT_RANGE is use to insert space within the file size without
|
|
* overwriting any existing data. The contents of the file beyond offset are
|
|
* shifted towards right by len bytes to create a hole. As such, this
|
|
* operation will increase the size of the file by len bytes.
|
|
*
|
|
* Different filesystems may implement different limitations on the granularity
|
|
* of the operation. Most will limit operations to filesystem block size
|
|
* boundaries, but this boundary may be larger or smaller depending on
|
|
* the filesystem and/or the configuration of the filesystem or file.
|
|
*
|
|
* Attempting to insert space using this flag at OR beyond the end of
|
|
* the file is considered an illegal operation - just use ftruncate(2) or
|
|
* fallocate(2) with mode 0 for such type of operations.
|
|
*/
|
|
#define FALLOC_FL_INSERT_RANGE 0x20
|
|
|
|
/*
|
|
* FALLOC_FL_UNSHARE_RANGE is used to unshare shared blocks within the
|
|
* file size without overwriting any existing data. The purpose of this
|
|
* call is to preemptively reallocate any blocks that are subject to
|
|
* copy-on-write.
|
|
*
|
|
* Different filesystems may implement different limitations on the
|
|
* granularity of the operation. Most will limit operations to filesystem
|
|
* block size boundaries, but this boundary may be larger or smaller
|
|
* depending on the filesystem and/or the configuration of the filesystem
|
|
* or file.
|
|
*
|
|
* This flag can only be used with allocate-mode fallocate, which is
|
|
* to say that it cannot be used with the punch, zero, collapse, or
|
|
* insert range modes.
|
|
*/
|
|
#define FALLOC_FL_UNSHARE_RANGE 0x40
|
|
|
|
#endif /* _UAPI_FALLOC_H_ */
|