Manual Pages  — STATFS

statfs – get file system statistics

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES ERRORS SEE ALSO HISTORY

Standard C Library (libc, -lc)

#include <sys/param.h>

#include <sys/mount.h>

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

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

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.

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.

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.

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