STATVFS(3)		   Linux Programmer's Manual		    STATVFS(3)



NAME
       statvfs, fstatvfs - get filesystem statistics

SYNOPSIS
       #include <sys/statvfs.h>

       int statvfs(const char *path, struct statvfs *buf);
       int fstatvfs(int fd, struct statvfs *buf);

DESCRIPTION
       The  function statvfs() returns information about a mounted filesystem.
       path is the pathname of any file within the mounted filesystem.	buf is
       a pointer to a statvfs structure defined approximately as follows:

	   struct statvfs {
	       unsigned long  f_bsize;	  /* Filesystem block size */
	       unsigned long  f_frsize;	  /* Fragment size */
	       fsblkcnt_t     f_blocks;	  /* Size of fs in f_frsize units */
	       fsblkcnt_t     f_bfree;	  /* Number of free blocks */
	       fsblkcnt_t     f_bavail;	  /* Number of free blocks for
					     unprivileged users */
	       fsfilcnt_t     f_files;	  /* Number of inodes */
	       fsfilcnt_t     f_ffree;	  /* Number of free inodes */
	       fsfilcnt_t     f_favail;	  /* Number of free inodes for
					     unprivileged users */
	       unsigned long  f_fsid;	  /* Filesystem ID */
	       unsigned long  f_flag;	  /* Mount flags */
	       unsigned long  f_namemax;  /* Maximum filename length */
	   };

       Here  the types fsblkcnt_t and fsfilcnt_t are defined in <sys/types.h>.
       Both used to be unsigned long.

       The field f_flag is a bit mask indicating  various  options  that  were
       employed	 when  mounting	 this filesystem.  It contains zero or more of
       the following flags:

       ST_MANDLOCK
	      Mandatory locking is permitted on the filesystem (see fcntl(2)).

       ST_NOATIME
	      Do not update access times; see mount(2).

       ST_NODEV
	      Disallow access to device special files on this filesystem.

       ST_NODIRATIME
	      Do not update directory access times; see mount(2).

       ST_NOEXEC
	      Execution of programs is disallowed on this filesystem.

       ST_NOSUID
	      The set-user-ID and set-group-ID bits are ignored by exec(3) for
	      executable files on this filesystem

       ST_RDONLY
	      This filesystem is mounted read-only.

       ST_RELATIME
	      Update atime relative to mtime/ctime; see mount(2).

       ST_SYNCHRONOUS
	      Writes  are  synched  to	the  filesystem	 immediately  (see the
	      description of O_SYNC in open(2)).

       It is unspecified whether all members of the returned struct have mean-
       ingful values on all filesystems.

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

       EBADF  (fstatvfs()) 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; see signal(7).

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

       ELOOP  (statvfs()) Too many symbolic links were encountered  in	trans-
	      lating path.

       ENAMETOOLONG
	      (statvfs()) path is too long.

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

       ENOMEM Insufficient kernel memory was available.

       ENOSYS The filesystem does not support this call.

       ENOTDIR
	      (statvfs())  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.

ATTRIBUTES
       For   an	  explanation	of   the  terms	 used  in  this	 section,  see
       attributes(7).

       +----------------------+---------------+---------+
       |Interface	      | Attribute     | Value	|
       +----------------------+---------------+---------+
       |statvfs(), fstatvfs() | Thread safety | MT-Safe |
       +----------------------+---------------+---------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

       Only the ST_NOSUID and ST_RDONLY flags of the f_flag field  are	speci-
       fied  in	 POSIX.1.   To	obtain definitions of the remaining flags, one
       must define _GNU_SOURCE.

NOTES
       The Linux kernel has system calls statfs(2) and fstatfs(2)  to  support
       this library call.

       In  glibc  versions  before  2.13,  statvfs() populated the bits of the
       f_flag field by scanning the mount options shown in /proc/mounts.  How-
       ever,  starting with Linux 2.6.36, the underlying statfs(2) system call
       provides the necessary information via the  f_flags  field,  and	 since
       glibc  version  2.13,  the statvfs() function will use information from
       that field rather than scanning /proc/mounts.

       The glibc implementations of

	  pathconf(path, _PC_REC_XFER_ALIGN);
	  pathconf(path, _PC_ALLOC_SIZE_MIN);
	  pathconf(path, _PC_REC_MIN_XFER_SIZE);

       respectively use the f_frsize, f_frsize, and f_bsize fields returned by
       a call to statvfs() with the argument path.

SEE ALSO
       statfs(2)

COLOPHON
       This  page  is  part of release 4.10 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest	  version     of     this    page,    can    be	   found    at
       https://www.kernel.org/doc/man-pages/.



Linux				  2016-03-15			    STATVFS(3)