--- name: "fstatfs" section: "2" platform: "freebsd" package: "base" version: "16.0-CURRENT-20261027-61c70dc16a79" release: "FreeBSD 16.0-CURRENT (2026-10-27)" platforms: ["linux", "freebsd", "macos"] url: "https://new.carta.tech/fstatfs" --- # fstatfs(2) get file system statistics ## NAME **statfs** – get file system statistics ## LIBRARY Standard C Library (libc, -lc) ## SYNOPSIS **#include \** **#include \** *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)](/autofs/4.md). - 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)](/gjournal/8.md)). - 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)](/df/1.md). - MNT\_LOCAL The file system resides locally. - MNT\_MULTILABEL Mandatory Access Control (MAC) support for individual objects (see [mac(4)](/mac/4.md)). - MNT\_NAMEDATTR The file system supports named attributes as described in [named\_attribute(7)](/named_attribute/7.md). - 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)](/ffs/4.md)). - 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)](/ffs/4.md). - 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)](/execve/2.md) 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 The **statfs()** function returns the value 0 if successful; 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)](/fhstatfs/2.md), [getfsstat(2)](/getfsstat/2.md), [named\_attribute(7)](/named_attribute/7.md) ## HISTORY The **statfs**() system call first appeared in 4.4BSD.