xref: /netbsd-src/share/man/man5/statvfs.5 (revision 6f8dc1509fa98d2f403ca646d8d47b18bead7044)

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.Dd September 22, 2019
.Dt STATVFS 5
.Os
.Sh NAME
.Nm statvfs
.Nd file system statistics
.Sh SYNOPSIS
.In sys/types.h
.In sys/statvfs.h
.Sh DESCRIPTION
The
.In sys/statvfs.h
header defines the structures and functions that
return information about a mounted file system.
The
.Nm statvfs
structure is defined as follows:
.Bd -literal
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 */

    /* The following are in units of f_frsize */
    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 */

    uint64_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 */
    char f_mntfromlabel[_VFS_MNAMELEN];	/* disk label name if avail */
};
.Ed
.Pp
The
.Fa f_flag
argument can have the following bits set:
.Bl -tag -width ST_SYNCHRONOUS
.It Dv ST_RDONLY
The filesystem is mounted read-only;
Even the super-user may not write on it.
.It Dv ST_NOEXEC
Files may not be executed from the filesystem.
.It Dv ST_NOSUID
Setuid and setgid bits on files are not honored when they are executed.
.It Dv ST_NODEV
Special files in the filesystem may not be opened.
.It Dv ST_UNION
Union with underlying filesystem instead of obscuring it.
.It Dv ST_SYNCHRONOUS
All I/O to the filesystem is done synchronously.
.It Dv ST_ASYNC
No filesystem I/O is done synchronously.
.It Dv ST_NOCOREDUMP
Don't write core dumps to this file system.
.It Dv ST_NOATIME
Never update access times.
.It Dv ST_SYMPERM
Recognize symbolic link permission.
.It Dv ST_NODEVMTIME
Never update modification times for device files.
.It Dv ST_LOG
Use logging (journaling).
.It Dv ST_LOCAL
The filesystem resides locally.
.It Dv ST_QUOTA
The filesystem has quotas enabled on it.
.It Dv ST_ROOTFS
Identifies the root filesystem.
.It Dv ST_EXRDONLY
The filesystem is exported read-only.
.It Dv ST_EXPORTED
The filesystem is exported for both reading and writing.
.It Dv ST_DEFEXPORTED
The filesystem is exported for both reading and writing to any Internet host.
.It Dv ST_EXPORTANON
The filesystem maps all remote accesses to the anonymous user.
.It Dv ST_EXKERB
The filesystem is exported with Kerberos uid mapping.
.It Dv ST_EXNORESPORT
Don't enforce reserved ports (NFS).
.It Dv ST_EXPUBLIC
Public export (WebNFS).
.El
.Pp
Fields that are undefined for a particular file system are set to \-1.
.Sh NOTES
.Bl -tag -width f_bavail
.It f_flag
The
.Fa f_flag
field is the same as the
.Fa f_flags
field in the
.Bx 4.3
.Ic statfs
system call.
.It f_fsid
Is defined to be
.Ft unsigned long
by the X/Open standard.
Unfortunately this is not enough space to store our
.Ft fsid_t ,
so we define an additional
.Fa f_fsidx
field.
.It f_bavail
Could historically be negative (in the
.Ic statfs
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
.Ft fsblkcnt_t
as an unsigned type, so in all cases where
.Fa f_bavail
would have been negative, we set it to 0.
In addition we provide
.Fa f_bresvd
which contains the amount of reserved blocks for the superuser, so
the old value of
.Fa f_bavail
can be easily computed as:
.Bd -literal
	old_bavail = f_bfree - f_bresvd;
.Ed
.El
.Sh SEE ALSO
.Xr statvfs 2
.Sh HISTORY
The
.In sys/statvfs.h
header first appeared in
.Nx 3.0 .