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STATFS(2) BSD Programmer's Manual STATFS(2)
NAME
statfs - get file system statistics
SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>
int
statfs(const char *path, struct statfs *buf);
int
fstatfs(int fd, struct statfs *buf);
int
getfsstat(struct statfs *buf, long bufsize, int flags);
DESCRIPTION
Statfs() returns information about a mounted file system. Path is the
path name of any file within the mounted filesystem. Buf is a pointer to
a statfs structure defined as follows:
typedef quad_t fsid_t;
#define MFSNAMELEN 16 /* length of fs type name, including null */
#define MNAMELEN 90 /* length of buffer for returned name */
struct statfs {
short f_type; /* XXX: deprecated filesystem type. */
short f_oflags; /* old mount flags (compat use only) */
long f_bsize; /* fundamental file system block size */
long f_iosize; /* optimal transfer block size */
long f_blocks; /* total data blocks in file system */
long f_bfree; /* free blocks in fs */
long f_bavail; /* free blocks avail to non-superuser */
long f_files; /* total file nodes in file system */
long f_ffree; /* free file nodes in fs */
fsid_t f_fsid; /* file system id */
uid_t f_owner; /* user that mounted the filesystem */
long f_flags; /* copy of mount flags */
long f_syncwrites; /* count of sync writes since mount */
long f_asyncwrites; /* count of async writes since mount */
long f_spare[1]; /* spare for later */
char f_fstypename[MFSNAMELEN]; /* fs type name */
char f_mntonname[MNAMELEN]; /* directory on which mounted */
char f_mntfromname[MNAMELEN]; /* mounted filesystem */
};
The flags that may be returned include the input/output flags described
in mount(2), along with the following additional output flags:
MNT_EXPORTABLE The filesystem may be exported through NFS (see
exports(5)).
MNT_LOCAL The filesystem resides locally.
MNT_QUOTA The filesystem has quotas enabled on it (see quota(1)).
MNT_ROOTFS Identifies the root filesystem.
MNT_UNIONDIR The filesystem stack may contain a union filesystem (see
mount_union(8)).
MNT_SOFTDEP The filesystem has soft updates enabled on it (see
tunefs(8)).
The filesystem type can be determined from the f_fstypename field by com-
paring it against the following strings:
``adosfs'' AmigaDOS Filesystem
``andrewfs'' Andrew Filesystem
``cd9660'' ISO9660 (also known as CDROM) Filesystem
``fdesc'' File Descriptor Filesystem
``kernfs'' Kernel Information Filesystem
``lfs'' Log-based Filesystem
``loopback'' Loopback (Minimal) Filesystem Layer
``mfs'' Memory-based Filesystem
``msdos'' MSDOS Filesystem
``nfs'' Sun-compatible Network Filesystem
``portal'' Portal Filesystem
``procfs'' /proc Filesystem
``romfs'' ROM Filesystem
``ufs'' Fast Filesystem
``umap'' User/Group Identifer Remapping Filesystem
``union'' Union (translucent) Filesystem
Fields that are undefined for a particular file system are set to -1.
Fstatfs() returns the same information about the filesystem where the
file referenced by descriptor fd resides.
Getfsstat() returns information about all mounted filesystems. The buf
argument is a pointer to a bufsize element array of statfs structures.
One statfs structure for each mounted filesystem is stored into this ar-
ray, up to the size specified by bufsize. If buf is NULL, getfsstat() re-
turns the number of mounted filesystems and does nothing further.
Normally, flags should be specified as MNT_WAIT. If flags is set to
MNT_NOWAIT, getfsstat() will return the information it has available
without requesting an update from each filesystem. Thus, some of the in-
formation may be out of date, but getfsstat() will not block waiting for
information from a filesystem that is unable to respond.
RETURN VALUES
Upon successful completion, statfs() and fstatfs() return a value of 0.
Otherwise, -1 is returned and the global variable errno is set to indi-
cate the error.
Upon successful completion, getfsstat() returns the number of statfs
structures stored into buf, or if buf is NULL, the total number of mount-
ed filesystems. Otherwise, -1 is returned and the global variable errno
is set to indicate the error.
ERRORS
Statfs() fails if one or more of the following are true:
[ENOTDIR] A component of the path prefix of path is not a directory.
[EINVAL] Path contains a character with the high-order bit set.
[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] Buf or path points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to the
file system.
Fstatfs() fails if one or more of the following are true:
[EBADF] Fd is not a valid open file descriptor.
[EFAULT] Buf points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to the
file system.
Getfsstat() fails if one or more of the following are true:
[EFAULT] Buf points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to the
filesystem.
SEE ALSO
mount(2), pathconf(2), stat(2)
HISTORY
The statfs functions first appeared in 4.4BSD.
BSDI BSD/OS November 15, 1999 3