Veritas™ File System 5.0.1 Programmer's Reference Guide

Setting fixed extent size

The following is an example code snippet for setting the fixed extent size of the

MY_PREFERRED_EXTSIZE attribute on a new file, MY_FILE, assuming

MY_PREFFERED_EXTSIZE is multiple of the file system block size:

#include <sys/fs/vx_ioctl.h>

struct vx_ext myext;

fd = open(MY_FILE, O_CREAT, 0644);

myext.ext_size = MY_PREFERRED_EXTSIZE;

myext.reserve = 0;

myext.flags = 0;

error = ioctl(fd, VX_SETEXT, &myext);

The following is an example code snippet for preallocating MY_FILESIZE_IN_BYTES

bytes of space on the new file, MY_FILE, assuming that the target file system block

size is THIS_FS_BLOCKSIZE:

#include <sys/fs/vx_ioctl.h>

struct vx_ext myext;

fd = open(MY_FILE, O_CREAT, 0644);

myext.ext_size =0;

myext.reserve = (MY_FILESIZE_IN_BYTES + THIS_FS_BLOCKSIZE)

/THIS_FS_BLOCKSIZE;

myext.flags = VX_CHGSIZE;

error = ioctl(fd, VX_SETEXT, &myext);

Veritas File System I/O

Extents