statvfs(3) — Linux manual page


statvfs(3)              Library Functions Manual              statvfs(3)

NAME         top

       statvfs, fstatvfs - get filesystem statistics

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <sys/statvfs.h>

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

DESCRIPTION         top

       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:

              Mandatory locking is permitted on the filesystem (see

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

              Disallow access to device special files on this

              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
              description of O_SYNC in open(2)).

       It is unspecified whether all members of the returned struct have
       meaningful values on all filesystems.

       fstatvfs() returns the same information about an open file
       referenced by descriptor fd.

RETURN VALUE         top

       On success, zero is returned.  On error, -1 is returned, and
       errno is set to indicate the error.

ERRORS         top

       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
              translating 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 directory.

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

ATTRIBUTES         top

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

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

VERSIONS         top

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

NOTES         top

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

       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.

STANDARDS         top


HISTORY         top


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

SEE ALSO         top


Linux man-pages 6.04           2023-03-30                     statvfs(3)

Pages that refer to this page: ioctl_xfs_fscounts(2)statfs(2)