STATFS(2) | System Calls Manual | STATFS(2)

# NAME

`statfs`, `fstatfs` — get file system statistics

# SYNOPSIS

`#include <sys/types.h>`
`#include <sys/mount.h>`

int
`statfs`(const char *path, struct statfs *buf);

int
`fstatfs`(int fd, struct statfs *buf);

# DESCRIPTION

`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 as follows:

    typedef struct { int32_t val[2]; } fsid_t;

    #define MFSNAMELEN   16 /* length of fs type name, including nul */
    #define MNAMELEN     90	/* length of buffer for returned name */

    struct statfs {
        u_int32_t	f_flags;	/* copy of mount flags */
        u_int32_t	f_bsize;	/* file system block size */
        u_int32_t	f_iosize;	/* optimal transfer block size */

    				/* unit is f_bsize */
        u_int64_t	f_blocks;	/* total data blocks in file system */
        u_int64_t	f_bfree;	/* free blocks in fs */
        int64_t	f_bavail;	/* free blocks avail to non-superuser */

        u_int64_t	f_files;	/* total file nodes in file system */
        u_int64_t	f_ffree;	/* free file nodes in fs */
        int64_t	f_favail;	/* free file nodes avail to non-root */

        u_int64_t	f_syncwrites;	/* count of sync writes since mount */
        u_int64_t	f_syncreads;	/* count of sync reads since mount */
        u_int64_t	f_asyncwrites;	/* count of async writes since mount */
        u_int64_t	f_asyncreads;	/* count of async reads since mount */

        fsid_t	f_fsid;		/* file system id */
        u_int32_t	f_namemax;	/* maximum filename length */
        uid_t	f_owner;	/* user that mounted the file system */
        u_int64_t	f_ctime;	/* last mount [-u] time */

        char f_fstypename[MFSNAMELEN]; /* fs type name */
        char f_mntonname[MNAMELEN];    /* directory on which mounted */
        char f_mntfromname[MNAMELEN];  /* mounted file system */
        char f_mntfromspec[MNAMELEN];  /* special for mount request */
        union mount_info mount_info;   /* per-filesystem mount options */
    };

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

Note that f_fsid will be empty unless the user is the superuser.

# RETURN VALUES

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

# ERRORS

`statfs`() fails if one or more of the following are true:

[`ENOTDIR`]
  A component of the path prefix of path is not a directory.
[`ENAMETOOLONG`]
  A component of a pathname exceeded `NAME_MAX` characters, or an entire pathname (including the terminating NUL) exceeded `PATH_MAX` bytes.
[`ENOENT`]
  The file referred to by path does not exist.
[`EACCES`]
  Search permission is denied for a component of the path prefix of path.
[`ELOOP`]
  Too many symbolic links were encountered in translating path.
[`EFAULT`]
  buf or path points to an invalid address.
[`EIO`]
  An I/O error occurred while reading from or writing to the file system.

`fstatfs`() fails if one or more of the following are true:

[`EBADF`]
  fd is not a valid open file descriptor.
[`EFAULT`]
  buf points to an invalid address.
[`EIO`]
  An I/O error occurred while reading from or writing to the file system.

# SEE ALSO

df(1), getfsstat(2), mount(2), stat(2)

# HISTORY

The `statfs`() function first appeared in 4.3BSD-Reno.

July 30, 2022 | Debian