STATVFS(5) BSD File Formats Manual STATVFS(5)NAMEstatvfs — file system statistics
SYNOPSIS
#include <sys/types.h>
#include <sys/statvfs.h>
DESCRIPTION
The <sys/statvfs.h> header defines the structures and functions that
return information about a mounted file system. The statvfs structure is
defined as follows:
typedef struct { int32_t val[2]; } fsid_t; /* file system id type */
#define VFS_NAMELEN 32 /* length of fs type name, including nul */
#define VFS_MNAMELEN 1024 /* length of buffer for returned name */
struct statvfs {
unsigned long f_flag; /* copy of mount exported flags */
unsigned long f_bsize; /* system block size */
unsigned long f_frsize; /* system fragment size */
unsigned long f_iosize; /* optimal file system block size */
fsblkcnt_t f_blocks; /* number of blocks in file system */
fsblkcnt_t f_bfree; /* free blocks avail in file system */
fsblkcnt_t f_bavail; /* free blocks avail to non-root */
fsblkcnt_t f_bresvd; /* blocks reserved for root */
fsfilcnt_t f_files; /* total file nodes in file system */
fsfilcnt_t f_ffree; /* free file nodes in file system */
fsfilcnt_t f_favail; /* free file nodes avail to non-root */
fsfilcnt_t f_fresvd; /* file nodes reserved for root */
uint64_t f_syncreads; /* count of sync reads since mount */
uint64_t f_syncwrites; /* count of sync writes since mount */
uint64_t f_asyncreads; /* count of async reads since mount */
uint64_t f_asyncwrites; /* count of async writes since mount */
unsigned long f_fsid; /* POSIX compliant file system id */
fsid_t f_fsidx; /* NetBSD compatible file system id */
unsigned long f_namemax;/* maximum filename length */
uid_t f_owner; /* user that mounted the file system */
uint32_t f_spare[4]; /* spare space */
char f_fstypename[VFS_NAMELEN]; /* fs type name */
char f_mntonname[VFS_MNAMELEN]; /* directory on which mounted */
char f_mntfromname[VFS_MNAMELEN]; /* mounted file system */
};
The f_flag argument can have the following bits set:
ST_RDONLY The filesystem is mounted read-only; Even the super-user
may not write on it.
ST_NOEXEC Files may not be executed from the filesystem.
ST_NOSUID Setuid and setgid bits on files are not honored when they
are executed.
ST_NODEV Special files in the filesystem may not be opened.
ST_UNION Union with underlying filesystem instead of obscuring it.
ST_SYNCHRONOUS All I/O to the filesystem is done synchronously.
ST_ASYNC No filesystem I/O is done synchronously.
ST_NOCOREDUMP Don't write core dumps to this file system.
ST_NOATIME Never update access times.
ST_SYMPERM Recognize symbolic link permission.
ST_NODEVMTIME Never update modification times for device files.
ST_LOG Use logging (journalling).
ST_LOCAL The filesystem resides locally.
ST_QUOTA The filesystem has quotas enabled on it.
ST_ROOTFS Identifies the root filesystem.
ST_EXRDONLY The filesystem is exported read-only.
ST_EXPORTED The filesystem is exported for both reading and writing.
ST_DEFEXPORTED The filesystem is exported for both reading and writing
to any Internet host.
ST_EXPORTANON The filesystem maps all remote accesses to the anonymous
user.
ST_EXKERB The filesystem is exported with Kerberos uid mapping.
ST_EXNORESPORT Don't enforce reserved ports (NFS).
ST_EXPUBLIC Public export (WebNFS).
Fields that are undefined for a particular file system are set to -1.
NOTES
f_flag The f_flag field is the same as the f_flags field in the 4.3BSD
statfs(2) system call.
f_fsid Is defined to be unsigned long by the X/Open standard. Unfor‐
tunately this is not enough space to store our fsid_t, so we
define an additional f_fsidx field.
f_bavail Could historically be negative (in the statfs(2) system call)
when the used space has exceeded the non-superuser free space.
In order to comply with the X/Open standard, we have to define
fsblkcnt_t as an unsigned type, so in all cases where f_bavail
would have been negative, we set it to 0. In addition we pro‐
vide f_bresvd which contains the amount of reserved blocks for
the superuser, so the old value of f_bavail can be easily com‐
puted as:
old_bavail = f_bfree - f_bresvd;
SEE ALSOstatvfs(2)HISTORY
The <sys/statvfs.h> header first appeared in NetBSD 3.0.
BSD April 10, 2009 BSD
