STATFS(2) Linux Programmer's Manual STATFS(2)
NAME
statfs, fstatfs - get file system statistics
SYNOPSIS
#include<sys/vfs.h>
intstatfs(constchar*path,structstatfs*buf);
intfstatfs(int fd,structstatfs*buf);
DESCRIPTION
statfs returns information about a mounted file system. path is the
path name of any file within the mounted filesystem. buf is a pointer
to a statfs structure defined as follows:
struct statfs {
long f_type; /* type of filesystem (see below) */
long f_bsize; /* optimal transfer block size */
long f_blocks; /* total data blocks in file system */
long f_bfree; /* free blocks in fs */
long f_bavail; /* free blocks avail to non-superuser */
long f_files; /* total file nodes in file system */
long f_ffree; /* free file nodes in fs */
fsid_t f_fsid; /* file system id */
long f_namelen; /* maximum length of filenames */
long f_spare[6]; /* spare for later */
};
File system types:
linux/affs_fs.h:
AFFS_SUPER_MAGIC 0xADFF
linux/efs_fs.h:
EFS_SUPER_MAGIC 0x00414A53
linux/ext_fs.h:
EXT_SUPER_MAGIC 0x137D
linux/ext2_fs.h:
EXT2_OLD_SUPER_MAGIC 0xEF51
EXT2_SUPER_MAGIC 0xEF53
linux/hpfs_fs.h:
HPFS_SUPER_MAGIC 0xF995E849
linux/iso_fs.h:
ISOFS_SUPER_MAGIC 0x9660
linux/minix_fs.h:
MINIX_SUPER_MAGIC 0x137F /* orig. minix */
MINIX_SUPER_MAGIC2 0x138F /* 30 char minix */
MINIX2_SUPER_MAGIC 0x2468 /* minix V2 */
MINIX2_SUPER_MAGIC2 0x2478 /* minix V2, 30 char names */
linux/msdos_fs.h:
MSDOS_SUPER_MAGIC 0x4d44
linux/ncp_fs.h:
NCP_SUPER_MAGIC 0x564c
linux/nfs_fs.h:
NFS_SUPER_MAGIC 0x6969
linux/proc_fs.h:
PROC_SUPER_MAGIC 0x9fa0
linux/smb_fs.h:
SMB_SUPER_MAGIC 0x517B
linux/sysv_fs.h:
XENIX_SUPER_MAGIC 0x012FF7B4
SYSV4_SUPER_MAGIC 0x012FF7B5
SYSV2_SUPER_MAGIC 0x012FF7B6
COH_SUPER_MAGIC 0x012FF7B7
linux/ufs_fs.h:
UFS_MAGIC 0x00011954
linux/xfs_fs.h:
XFS_SUPER_MAGIC 0x58465342
linux/xia_fs.h:
_XIAFS_SUPER_MAGIC 0x012FD16D
Nobody knows what f_fsid is supposed to contain (but see below).
Fields that are undefined for a particular file system are set to 0.
fstatfs returns the same information about an open file referenced by
descriptor fd.
RETURNVALUE
On success, zero is returned. On error, -1 is returned, and errno is
set appropriately.
ERRORS
For statfs:
ENOTDIR
A component of the path prefix of path is not a directory.
ENAMETOOLONG
path is too long.
ENOENT The file referred to by path does not exist.
EACCES Search permission is denied for a component of the path prefix
of path.
ELOOP Too many symbolic links were encountered in translating path.
EFAULT Buf or path points to an invalid address.
EIO An I/O error occurred while reading from or writing to the file
system.
ENOMEM Insufficient kernel memory was available.
ENOSYS The filesystem path is on does not support statfs.
For fstatfs:
EBADF fd is not a valid open file descriptor.
EFAULT buf points to an invalid address.
EIO An I/O error occurred while reading from or writing to the file
system.
ENOSYS The filesystem fd is open on does not support statfs.
CONFORMINGTO
The Linux statfs was inspired by the 4.4BSD one (but they do not use
the same structure).
f_fsid
Solaris and POSIX 1003.1-2001 have a system call statvfs that returns a
structstatvfs (defined in <sys/statvfs.h>) containing an unsignedlong
f_fsid. Linux, SunOS, HPUX, 4.4BSD have a system call statfs that
returns a structstatfs (defined in <sys/vfs.h>) containing a fsid_t
f_fsid, where fsid_t is defined as struct{intval[2];}. The same
holds for FreeBSD, except that it uses the include file <sys/mount.h>.
The general idea is that f_fsid contains some random stuff such that
the pair (f_fsid,ino) uniquely determines a file. Some OSes use (a
variation on) the device number, or the device number combined with the
filesystem type. Several OSes restrict giving out the f_fsid field to
the superuser only (and zero it for nonprivileged users), because this
field is used in the filehandle of the filesystem when NFS-exported,
and giving it out is a security concern.
Under some OSes the fsid can be used as second parameter to the sysfs()
system call.
SEEALSO
stat(2)
Linux 2.0.30 1997-08-21 STATFS(2)
Take our 
