STATFS(2) FreeBSD System Calls Manual STATFS(2)
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).
SEE ALSO
fhstatfs(2), getfsstat(2), named_attribute(7)
HISTORY
The statfs() system call first appeared in 4.4BSD.
FreeBSD 15.1-STABLE-HBSD July 20, 2025 STATFS(2)