NAME

statfs —

get file system statistics

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/param.h>
#include <sys/mount.h>

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

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

DESCRIPTION

The statfs() system call returns information about a mounted file system. The path argument is the path name of any file within the mounted file system. The buf argument is a pointer to a statfs structure defined as follows:

typedef struct fsid { int32_t val[2]; } fsid_t; /* file system id type */

/*
 * filesystem statistics
 */

#define	MFSNAMELEN	16		/* length of type name including null */
#define	MNAMELEN	1024		/* size of on/from name bufs */
#define	STATFS_VERSION	0x20140518	/* current version number */

struct statfs {
uint32_t f_version;		/* structure version number */
uint32_t f_type;		/* type of filesystem */
uint64_t f_flags;		/* copy of mount exported flags */
uint64_t f_bsize;		/* filesystem fragment size */
uint64_t f_iosize;		/* optimal transfer block size */
uint64_t f_blocks;		/* total data blocks in filesystem */
uint64_t f_bfree;		/* free blocks in filesystem */
int64_t	 f_bavail;		/* free blocks avail to non-superuser */
uint64_t f_files;		/* total file nodes in filesystem */
int64_t	 f_ffree;		/* free nodes avail to non-superuser */
uint64_t f_syncwrites;		/* count of sync writes since mount */
uint64_t f_asyncwrites;		/* count of async writes since mount */
uint64_t f_syncreads;		/* count of sync reads since mount */
uint64_t f_asyncreads;		/* count of async reads since mount */
uint64_t f_spare[10];		/* unused spare */
uint32_t f_namemax;		/* maximum filename length */
uid_t	  f_owner;		/* user that mounted the filesystem */
fsid_t	  f_fsid;		/* filesystem id */
char	  f_charspare[80];	    /* spare string space */
char	  f_fstypename[MFSNAMELEN]; /* filesystem type name */
char	  f_mntfromname[MNAMELEN];  /* mounted filesystem */
char	  f_mntonname[MNAMELEN];    /* directory on which mounted */
};

The flags that may be returned include:

MNT_RDONLY: The file system is mounted read-only; Even the super-user may not write on it.
MNT_NOEXEC: Files may not be executed from the file system.
MNT_NOSUID: Setuid and setgid bits on files are not honored when they are executed.
MNT_SYNCHRONOUS: All I/O to the file system is done synchronously.
MNT_ASYNC: No file system I/O is done synchronously.
MNT_SOFTDEP: Soft updates being done (see ffs(7)).
MNT_GJOURNAL: Journaling with gjournal is enabled (see gjournal(8)).
MNT_SUIDDIR: Special handling of SUID bit on directories.
MNT_UNION: Union with underlying file system.
MNT_NOSYMFOLLOW: Symbolic links are not followed.
MNT_NOCLUSTERR: Read clustering is disabled.
MNT_NOCLUSTERW: Write clustering is disabled.
MNT_MULTILABEL: Mandatory Access Control (MAC) support for individual objects (see mac(4)).
MNT_ACLS: Access Control List (ACL) support enabled.
MNT_LOCAL: The file system resides locally.
MNT_QUOTA: The file system has quotas enabled on it.
MNT_ROOTFS: Identifies the root file system.
MNT_EXRDONLY: The file system is exported read-only.
MNT_NOATIME: Updating of file access times is disabled.
MNT_USER: The file system has been mounted by a user.
MNT_EXPORTED: The file system is exported for both reading and writing.
MNT_DEFEXPORTED: The file system is exported for both reading and writing to any Internet host.
MNT_EXPORTANON: The file system maps all remote accesses to the anonymous user.
MNT_EXKERB: The file system is exported with Kerberos uid mapping.
MNT_EXPUBLIC: The file system is exported publicly (WebNFS).

Fields that are undefined for a particular file system are set to -1. The fstatfs() system call returns the same information about an open file referenced by descriptor fd.

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

The statfs() system call fails if one or more of the following are true:

[ENOTDIR]: A component of the path prefix of path is not a directory.
[ENAMETOOLONG]: The length of a component of path exceeds 255 characters, or the length of path exceeds 1023 characters.
[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]: The buf or path argument points to an invalid address.
[EIO]: An I/O error occurred while reading from or writing to the file system.
[EINTEGRITY]: Corrupted data was detected while reading from the file system.

The fstatfs() system call fails if one or more of the following are true:

[EBADF]: The fd argument is not a valid open file descriptor.
[EFAULT]: The buf argument points to an invalid address.
[EIO]: An I/O error occurred while reading from or writing to the file system.
[EINTEGRITY]: Corrupted data was detected while reading from the file system.

HISTORY

The statfs() system call first appeared in 4.4BSD.