tail head cat sleep
QR code linking to this page

Manual Pages  — STATFS


statfs – get file system statistics



Standard C Library (libc, -lc)


#include <sys/param.h>
#include <sys/mount.h>

statfs(const char *path, struct statfs *buf);

fstatfs(int fd, struct statfs *buf);


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        88              /* size of on/from name bufs */ #define STATFS_VERSION  0x20030518      /* 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_RDONLY The file system is mounted read-only; Even the super-user may not write on it.
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.
  All I/O to the file system is done synchronously.
MNT_ASYNC No file system I/O is done synchronously.
MNT_SOFTDEP Soft updates being done (see ffs(7)).
MNT_GJOURNAL Journaling with gjournal is enabled (see gjournal(8)).
MNT_SUIDDIR Special handling of SUID bit on directories.
MNT_UNION Union with underlying file system.
  Symbolic links are not followed.
MNT_NOCLUSTERR Read clustering is disabled.
MNT_NOCLUSTERW Write clustering is disabled.
MNT_MULTILABEL Mandatory Access Control (MAC) support for individual objects (see mac(4)).
MNT_ACLS Access Control List (ACL) support enabled.
MNT_LOCAL The file system resides locally.
MNT_QUOTA The file system has quotas enabled on it.
MNT_ROOTFS Identifies the root file system.
MNT_EXRDONLY The file system is exported read-only.
MNT_NOATIME Updating of file access times is disabled.
MNT_USER The file system has been mounted by a user.
MNT_EXPORTED The file system is exported for both reading and writing.
  The file system is exported for both reading and writing to any Internet host.
MNT_EXPORTANON The file system maps all remote accesses to the anonymous user.
MNT_EXKERB The file system is exported with Kerberos uid mapping.
MNT_EXPUBLIC The file system is exported publicly (WebNFS).

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.


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.


The statfs() system call fails if one or more of the following are true:
  A component of the path prefix of path is not a directory.
  The length of a component of path exceeds 255 characters, or the length of path exceeds 1023 characters.
  The file referred to by path does not exist.
  Search permission is denied for a component of the path prefix of path.
  Too many symbolic links were encountered in translating path.
  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.

The fstatfs() system call fails if one or more of the following are true:
  The fd argument is not a valid open file descriptor.
  The buf argument points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to the file system.




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

STATFS (2) November 1, 2006

tail head cat sleep
QR code linking to this page

Please direct any comments about this manual page service to Ben Bullock. Privacy policy.

Ken Thompson has an automobile which he helped design. Unlike most automobiles, it has neither speedometer, nor gas gauge, nor any of the other numerous idiot lights which plague the modern driver. Rather, if the driver makes a mistake, a giant “?” lights up in the center of the dashboard. “The experienced driver,” says Thompson, “will usually know what's wrong.”