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.\"	@(#)statfs.2	8.5 (Berkeley) 5/24/95
.\"
.Dd March 29, 2023
.Dt STATFS 2
.Os
.Sh NAME
.Nm statfs
.Nd get file system statistics
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/param.h
.In sys/mount.h
.Ft int
.Fn statfs "const char *path" "struct statfs *buf"
.Ft int
.Fn fstatfs "int fd" "struct statfs *buf"
.Sh DESCRIPTION
The
.Fn statfs
system call
returns information about a mounted file system.
The
.Fa path
argument
is the path name of any file within the mounted file system.
The
.Fa buf
argument
is a pointer to a
.Vt statfs
structure defined as follows:
.Bd -literal
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 */
};
.Ed
.Pp
The flags that may be returned include:
.Bl -tag -width MNT_SYNCHRONOUS
.It Dv MNT_RDONLY
The file system is mounted read-only;
Even the super-user may not write on it.
.It Dv MNT_NOEXEC
Files may not be executed from the file system.
.It Dv MNT_NOSUID
Setuid and setgid bits on files are not honored when they are executed.
.It Dv MNT_SYNCHRONOUS
All I/O to the file system is done synchronously.
.It Dv MNT_ASYNC
No file system I/O is done synchronously.
.It Dv MNT_SOFTDEP
Soft updates being done (see
.Xr ffs 7 ) .
.It Dv MNT_GJOURNAL
Journaling with gjournal is enabled (see
.Xr gjournal 8 ) .
.It Dv MNT_SUIDDIR
Special handling of SUID bit on directories.
.It Dv MNT_UNION
Union with underlying file system.
.It Dv MNT_NOSYMFOLLOW
Symbolic links are not followed.
.It Dv MNT_NOCLUSTERR
Read clustering is disabled.
.It Dv MNT_NOCLUSTERW
Write clustering is disabled.
.\".It Dv MNT_JAILDEVFS
.\"XXX
.It Dv MNT_MULTILABEL
Mandatory Access Control (MAC) support for individual objects
(see
.Xr mac 4 ) .
.It Dv MNT_ACLS
Access Control List (ACL) support enabled.
.It Dv MNT_LOCAL
The file system resides locally.
.It Dv MNT_QUOTA
The file system has quotas enabled on it.
.It Dv MNT_ROOTFS
Identifies the root file system.
.It Dv MNT_EXRDONLY
The file system is exported read-only.
.It Dv MNT_NOATIME
Updating of file access times is disabled.
.It Dv MNT_USER
The file system has been mounted by a user.
.\".It Dv MNT_IGNORE
.\"XXX
.It Dv MNT_EXPORTED
The file system is exported for both reading and writing.
.It Dv MNT_DEFEXPORTED
The file system is exported for both reading and writing to any Internet host.
.It Dv MNT_EXPORTANON
The file system maps all remote accesses to the anonymous user.
.It Dv MNT_EXKERB
The file system is exported with Kerberos uid mapping.
.It Dv MNT_EXPUBLIC
The file system is exported publicly (WebNFS).
.El
.Pp
Fields that are undefined for a particular file system are set to -1.
The
.Fn fstatfs
system call
returns the same information about an open file referenced by descriptor
.Fa fd .
.Sh RETURN VALUES
.Rv -std
.Sh ERRORS
The
.Fn statfs
system call
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix of
.Fa path
is not a directory.
.It Bq Er ENAMETOOLONG
The length of a component of
.Fa path
exceeds 255 characters,
or the length of
.Fa path
exceeds 1023 characters.
.It Bq Er ENOENT
The file referred to by
.Fa path
does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix of
.Fa path .
.It Bq Er ELOOP
Too many symbolic links were encountered in translating
.Fa path .
.It Bq Er EFAULT
The
.Fa buf
or
.Fa path
argument
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er EINTEGRITY
Corrupted data was detected while reading from the file system.
.El
.Pp
The
.Fn fstatfs
system call
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa fd
argument
is not a valid open file descriptor.
.It Bq Er EFAULT
The
.Fa buf
argument
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er EINTEGRITY
Corrupted data was detected while reading from the file system.
.El
.Sh NOTES
The fields in the
.Vt statfs
structure have been defined to provide the parameters relevant for
traditional
.Tm 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 FAT13 file systems
reports the number of available and of free root directory entries
instead of inodes
.Po
where 1 to 21 such directory entries are required to store
each file or directory name or disk label
.Pc .
.Sh SEE ALSO
.Xr fhstatfs 2 ,
.Xr getfsstat 2
.Sh HISTORY
The
.Fn statfs
system call first appeared in
.Bx 4.4 .