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- #ifndef _FALLOC_H_
- #define _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
- #endif /* _FALLOC_H_ */
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