statfs.h File

AIX Version 4 Files Reference

statfs.h File

Purpose

Describes the structure of the statistics returned by the statfs, fstatfs, or ustat subroutine.

Description

The statfs and fstatfs subroutines return information on a mounted (virtual) file system in the form of a statfs structure. The /usr/include/sys/statfs.h file describes the statfs structure, which contains the following fields:

f_version

Version number of the statfs structure. This value is currently 0.

f_length

Length of the buffer that contains the returned information. This value is currently 0.

f_type

Type of information returned. This value is currently 0.

f_bsize

Optimal block size of the file system.

f_blocks

Total number of blocks in the system.

f_bfree

Number of free blocks in the file system. The size of a free block is given in the f_bsize field.

f_bavail

Number of free blocks available to a nonroot user.

f_files

Total number of file nodes in the file system.

f_ffree

Number of free file nodes in the file system.

f_fsid

File system ID.

f_vfstype

Type of this virtual file system. Possible values are:

MNT_JFS	AIX Version 3 Journaled File System (JFS)
MNT_NFS	SUN network file system
MNT_CDROM	CD-ROM file system.

f_fsize

Fundamental block size of the file system.

f_fname

File system name. The value returned by this field depends on the type of file system:

JFS	Value returned is copied from the `s_fname` field of the superblock (see the filsys.h file format). You can set this value at the time the file system is created by using the mkfs command with the -l flag. This field gives the preferred mount point for the file system. Note: The `s_fname` field in the superblock is only 6 bytes wide. Longer names are truncated to fit.
CD-ROM	The field is filled with null bytes because the `f_fname` field is not implemented.
NFS	The field is filled with null bytes because the `f_fname` field is not implemented.

f_fpack

File system pack name. The value returned by this field depends on the file system type:

JFS	The value returned is copied from the `s_fpack` field of the superblock (see the filsys.h file format). You can set this value at the time the file system is created using the mkfs command with the -v flag. Note: The `s_fpack` field in the superblock is only 6 bytes wide. Longer pack names are truncated to fit.
CD-ROM	The value is copied from the volume identifier field in the primary volume descriptor.
NFS	The field is filled with null bytes because the `f_fname` field is not implemented.

f_name_max

Maximum length of a component name for this file system.

Note: Fields that are not defined for a particular file system are set to a value of -1.

The ustat system returns information on a mounted file system in the form of a ustat structure. The ustat structure, which is defined in the /usr/include/ustat.h file, contains the following fields:

`f_tfree`	Total number of free blocks in the file system. The size of a free block is given in by the UBSIZE constant. See the param.h file for a description of UBSIZE.
`f_inode`	Number of free i-nodes in the file system.
`f_fname`	File system name.
`f_fpack`	File system pack name.

Implementation Specifics

This file is part of Base Operating System (BOS) Runtime.

Files

statfs.h	Path to the statfs.h file.
ustat.h	Path to the ustat.h file.

Related Information

The filsys.h file format, param.h file, vmount.h file.

The statfs, fstatfs, or ustat subroutine.

The Header Files Overview defines header files, describes how they are used, and lists several of the documented header files.