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

       statvfs, fstatvfs - get filesystem statistics

       #include <sys/statvfs.h>

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

       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 em-
       ployed  when mounting this filesystem.  It contains zero or more of the
       following flags:

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

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

              Disallow access to device special files on this filesystem.

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

              Execution of programs is disallowed on this filesystem.

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

              This filesystem is mounted read-only.

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

              Writes  are  synched  to the filesystem immediately (see the de-
              scription 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.

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

       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.

              (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.

              (statvfs())  A component of the path prefix of path is not a di-

              Some values were too large to be  represented  in  the  returned

       For  an  explanation  of  the  terms  used  in  this  section,  see at-

       |Interface             | Attribute     | Value   |
       |statvfs(), fstatvfs() | Thread safety | MT-Safe |
       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.

       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.


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       description of the project, information about reporting bugs,  and  the
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Linux                             2017-09-15                        STATVFS(3)
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