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Diffstat (limited to 'include/uapi/linux/falloc.h')
-rw-r--r-- | include/uapi/linux/falloc.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h new file mode 100644 index 000000000..51398fa57 --- /dev/null +++ b/include/uapi/linux/falloc.h @@ -0,0 +1,80 @@ +/* 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_ */ |