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_ACLS: Access Control List (ACL) support enabled.
MNT_ASYNC: No file system I/O is done synchronously.
MNT_AUTOMOUNTED: The filesystem was auto-mounted, see autofs(4).
MNT_DEFEXPORTED: The file system is exported for both reading and writing to any Internet host.
MNT_GJOURNAL: Journaling with gjournal is enabled (see gjournal(8)).
MNT_EXKERB: The file system is exported with Kerberos uid mapping.
MNT_EXPORTANON: The file system maps all remote accesses to the anonymous user.
MNT_EXPORTED: The file system is exported for both reading and writing.
MNT_EXPUBLIC: The file system is exported publicly (WebNFS).
MNT_EXRDONLY: The file system is exported read-only.
MNT_IGNORE: The file system should not be listed, e.g. by df(1).
MNT_LOCAL: The file system resides locally.
MNT_MULTILABEL: Mandatory Access Control (MAC) support for individual objects (see mac(4)).
MNT_NAMEDATTR: The file system supports named attributes as described in named_attribute(7).
MNT_NFS4ACLS: ACLs in NFSv4 variant are supported.
MNT_NOATIME: Updating of file access times is disabled.
MNT_NOCLUSTERR: Read clustering is disabled.
MNT_NOCLUSTERW: Write clustering is disabled.
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_NOSYMFOLLOW: Symbolic links are not followed.
MNT_SOFTDEP: Soft updates being done (see ffs(4)).
MNT_SUIDDIR: Special handling of SUID bit on directories.
MNT_SUJ: Soft-updates with journaling being done.
MNT_SYNCHRONOUS: All I/O to the file system is done synchronously.
MNT_QUOTA: The file system has quotas enabled on it.
MNT_RDONLY: The file system is mounted read-only; Even the super-user may not write on it.
MNT_ROOTFS: Identifies the root file system.
MNT_UNION: Union with underlying file system.
MNT_UNTRUSTED: The file system was mounted with the untrusted option, which indicates media of unknown provenance or integrity. Currently honored by ffs(4).
MNT_USER: The file system has been mounted by a user.
MNT_VERIFIED: The file system is marked as verified, no fingerprint check on execve(2) is needed, see mac_veriexec(4).

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.

NOTES

The fields in the statfs structure have been defined to provide the parameters relevant for traditional UNIX file systems. For some other file systems, values that have similar, but not identical, semantics to those described above may be returned. An example is msdosfs, which in case of FAT12 or FAT16 file systems reports the number of available and of free root directory entries instead of inodes (where 1 to 21 such directory entries are required to store each file or directory name or disk label).

HISTORY

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