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man:statvfs

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 4.16 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 2017-09-15 STATVFS(3)

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