fstatfs

STATFS(2)		  Linux Programmer’s Manual		    STATFS(2)



NAME
       statfs, fstatfs - get file system statistics

SYNOPSIS
       #include <sys/vfs.h>    /* or <sys/statfs.h> */

       int statfs(const char *path, struct statfs *buf);
       int fstatfs(int fd, struct statfs *buf);

DESCRIPTION
       The  function  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 approximately 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 */
	      };

	      File system types:

		 ADFS_SUPER_MAGIC      0xadf5
		 AFFS_SUPER_MAGIC      0xADFF
		 BEFS_SUPER_MAGIC      0x42465331
		 BFS_MAGIC	       0x1BADFACE
		 CIFS_MAGIC_NUMBER     0xFF534D42
		 CODA_SUPER_MAGIC      0x73757245
		 COH_SUPER_MAGIC       0x012FF7B7
		 CRAMFS_MAGIC	       0x28cd3d45
		 DEVFS_SUPER_MAGIC     0x1373
		 EFS_SUPER_MAGIC       0x00414A53
		 EXT_SUPER_MAGIC       0x137D
		 EXT2_OLD_SUPER_MAGIC  0xEF51
		 EXT2_SUPER_MAGIC      0xEF53
		 EXT3_SUPER_MAGIC      0xEF53
		 HFS_SUPER_MAGIC       0x4244
		 HPFS_SUPER_MAGIC      0xF995E849
		 HUGETLBFS_MAGIC       0x958458f6
		 ISOFS_SUPER_MAGIC     0x9660
		 JFFS2_SUPER_MAGIC     0x72b6
		 JFS_SUPER_MAGIC       0x3153464a
		 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 */
		 MSDOS_SUPER_MAGIC     0x4d44
		 NCP_SUPER_MAGIC       0x564c
		 NFS_SUPER_MAGIC       0x6969
		 NTFS_SB_MAGIC	       0x5346544e
		 OPENPROM_SUPER_MAGIC  0x9fa1
		 PROC_SUPER_MAGIC      0x9fa0
		 QNX4_SUPER_MAGIC      0x002f
		 REISERFS_SUPER_MAGIC  0x52654973
		 ROMFS_MAGIC	       0x7275
		 SMB_SUPER_MAGIC       0x517B
		 SYSV2_SUPER_MAGIC     0x012FF7B6
		 SYSV4_SUPER_MAGIC     0x012FF7B5
		 TMPFS_MAGIC	       0x01021994
		 UDF_SUPER_MAGIC       0x15013346
		 UFS_MAGIC	       0x00011954
		 USBDEVICE_SUPER_MAGIC 0x9fa2
		 VXFS_SUPER_MAGIC      0xa501FCF5
		 XENIX_SUPER_MAGIC     0x012FF7B4
		 XFS_SUPER_MAGIC       0x58465342
		 _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.

RETURN VALUE
       On  success, zero is returned.  On error, -1 is returned, and errno is
       set appropriately.

ERRORS
       EBADF  (fstatfs) fd is not a valid open file descriptor.

       EACCES (statfs) Search permission is denied for	a  component  of  the
	      path prefix of path.

       ELOOP  (statfs)	Too many symbolic links were encountered in translat-
	      ing path.

       ENAMETOOLONG
	      (statfs) path is too long.

       ENOENT (statfs) The file referred to by path does not exist.

       ENOTDIR
	      (statfs) A component of the path prefix of path is not a direc-
	      tory.

       EFAULT buf or path points to an invalid address.

       EINTR  This call was interrupted by a signal.

       EIO    An I/O error occurred while reading from the file system.

       ENOMEM Insufficient kernel memory was available.

       ENOSYS The file system does not support this call.

       EOVERFLOW
	      Some  values  were  too large to be represented in the returned
	      struct.


CONFORMING TO
       The Linux statfs was inspired by the 4.4BSD one (but they do  not  use
       the same structure).

NOTES ON f_fsid
       Solaris,	 Irix  and POSIX have a system call statvfs(2) that returns a
       struct statvfs (defined in  <sys/statvfs.h>)  containing	 an  unsigned
       long  f_fsid.   Linux,  SunOS,  HPUX, 4.4BSD have a system call statfs
       that returns a struct statfs (defined  in  <sys/vfs.h>)	containing  a
       fsid_t f_fsid, where fsid_t is defined as struct { int val[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.

NOTES
       The kernel has system calls statfs, fstatfs,  statfs64,	fstatfs64  to
       support this library call.

       Some   systems	only   have  <sys/vfs.h>,  other  systems  also	 have
       <sys/statfs.h>, where the former includes  the  latter.	So  it	seems
       including the former is the best choice.

       LSB  has	 deprecated the library calls [f]statfs() and tells us to use
       [f]statvfs() instead.

SEE ALSO
       stat(2), statvfs(2)



Linux 2.6.0			  2003-08-22			    STATFS(2)