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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

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