• 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:
  

  
  struct statfs {
     long    f_type;     /* type of file system (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
  

  EACCES

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

  EBADF

  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

  Too many symbolic links were encountered in translating path .

  ENAMETOOLONG

  path is too long.

  ENOENT

  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

  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> ) containing 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 OSes 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 3.19 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/.

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