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 pathname of any file within the
       mounted file system.  buf is a pointer to a statfs structure defined approximately as follows:

           #if __WORDSIZE == 32          /* System word size */
           # define __UWORD_TYPE         unsigned int
           #else /* __WORDSIZE == 64 */
           # define __SWORD_TYPE         long int
           #endif

           struct statfs {
               __SWORD_TYPE f_type;    /* type of file system (see below) */
               __SWORD_TYPE f_bsize;   /* optimal transfer block size */
               fsblkcnt_t   f_blocks;  /* total data blocks in file system */
               fsblkcnt_t   f_bfree;   /* free blocks in fs */
               fsblkcnt_t   f_bavail;  /* free blocks available to
                                          unprivileged user */
               fsfilcnt_t   f_files;   /* total file nodes in file system */
               fsfilcnt_t   f_ffree;   /* free file nodes in fs */
               fsid_t       f_fsid;    /* file system id */
               __SWORD_TYPE f_namelen; /* maximum length of filenames */
               __SWORD_TYPE f_frsize;  /* fragment size (since Linux 2.6) */
               __SWORD_TYPE f_spare[5];
           };

           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
              EXT4_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
       EACCES (statfs()) Search permission is denied for a component of the path prefix of path.  (See also path_resolution(7).)

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

       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.

       ELOOP  (statfs()) Too many symbolic links were encountered in translating path.

       ENAMETOOLONG
              (statfs()) path is too long.

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

       ENOMEM Insufficient kernel memory was available.

       ENOSYS The file system does not support this call.

       ENOTDIR
              (statfs()) A component of the path prefix of path is not a directory.

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

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

NOTES
       The kernel has system calls statfs(), fstatfs(), statfs64(), and 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 statfs() and fstatfs() and tells us to use statvfs(2) and fstatvfs(2) instead.

   The f_fsid field
       Solaris, Irix and POSIX have a system call statvfs(2) that returns a struct statvfs (defined in <sys/statvfs.h>) contain-
       ing  an  unsigned  long  f_fsid.   Linux,  SunOS,  HP-UX, 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 operating systems use (a variation on) the device number, or the device number combined with the  file-system  type.
       Several  OSes  restrict  giving  out the f_fsid field to the superuser only (and zero it for unprivileged users), because
       this field is used in the filehandle of the file system when NFS-exported, and giving it out is a security concern.

       Under some OSes the fsid can be used as second argument to the sysfs() system call.

SEE ALSO
       stat(2), statvfs(2), path_resolution(7)

COLOPHON
       This page is part of release 3.25 of the Linux man-pages project.  A description of the project,  and  information  about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2010-06-13                                                  STATFS(2)