xref: /netbsd-src/share/man/man5/statvfs.5 (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
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30.\"	@(#)statfs.2	8.5 (Berkeley) 5/24/95
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32.Dd April 10, 2009
33.Dt STATVFS 5
34.Os
35.Sh NAME
36.Nm statvfs
37.Nd file system statistics
38.Sh SYNOPSIS
39.In sys/types.h
40.In sys/statvfs.h
41.Sh DESCRIPTION
42The
43.In sys/statvfs.h
44header defines the structures and functions that
45return information about a mounted file system.
46The
47.Nm statvfs
48structure is defined as follows:
49.Bd -literal
50typedef struct { int32_t val[2]; } fsid_t;	/* file system id type */
51
52#define VFS_NAMELEN  32 	/* length of fs type name, including nul */
53#define VFS_MNAMELEN 1024	/* length of buffer for returned name */
54
55struct statvfs {
56	unsigned long	f_flag;	  /* copy of mount exported flags */
57	unsigned long	f_bsize;  /* system block size */
58	unsigned long	f_frsize; /* system fragment size */
59	unsigned long	f_iosize; /* optimal file system block size */
60
61	fsblkcnt_t	f_blocks; /* number of blocks in file system */
62	fsblkcnt_t	f_bfree;  /* free blocks avail in file system */
63	fsblkcnt_t	f_bavail; /* free blocks avail to non-root */
64	fsblkcnt_t	f_bresvd; /* blocks reserved for root */
65
66	fsfilcnt_t	f_files;  /* total file nodes in file system */
67	fsfilcnt_t	f_ffree;  /* free file nodes in file system */
68	fsfilcnt_t	f_favail; /* free file nodes avail to non-root */
69	fsfilcnt_t	f_fresvd; /* file nodes reserved for root */
70
71	uint64_t  f_syncreads;	  /* count of sync reads since mount */
72	uint64_t  f_syncwrites;	  /* count of sync writes since mount */
73
74	uint64_t  f_asyncreads;	  /* count of async reads since mount */
75	uint64_t  f_asyncwrites;  /* count of async writes since mount */
76
77	unsigned long	f_fsid;   /* POSIX compliant file system id */
78	fsid_t          f_fsidx;  /* NetBSD compatible file system id */
79
80	unsigned long	f_namemax;/* maximum filename length */
81	uid_t		f_owner; /* user that mounted the file system */
82
83	uint32_t	f_spare[4]; /* spare space */
84
85	char	f_fstypename[VFS_NAMELEN]; /* fs type name */
86	char	f_mntonname[VFS_MNAMELEN]; /* directory on which mounted */
87	char	f_mntfromname[VFS_MNAMELEN]; /* mounted file system */
88};
89.Ed
90.Pp
91The
92.Fa f_flag
93argument can have the following bits set:
94.Bl -tag -width ST_SYNCHRONOUS
95.It Dv ST_RDONLY
96The filesystem is mounted read-only;
97Even the super-user may not write on it.
98.It Dv ST_NOEXEC
99Files may not be executed from the filesystem.
100.It Dv ST_NOSUID
101Setuid and setgid bits on files are not honored when they are executed.
102.It Dv ST_NODEV
103Special files in the filesystem may not be opened.
104.It Dv ST_UNION
105Union with underlying filesystem instead of obscuring it.
106.It Dv ST_SYNCHRONOUS
107All I/O to the filesystem is done synchronously.
108.It Dv ST_ASYNC
109No filesystem I/O is done synchronously.
110.It Dv ST_NOCOREDUMP
111Don't write core dumps to this file system.
112.It Dv ST_NOATIME
113Never update access times.
114.It Dv ST_SYMPERM
115Recognize symbolic link permission.
116.It Dv ST_NODEVMTIME
117Never update modification times for device files.
118.It Dv ST_LOG
119Use logging (journalling).
120.It Dv ST_LOCAL
121The filesystem resides locally.
122.It Dv ST_QUOTA
123The filesystem has quotas enabled on it.
124.It Dv ST_ROOTFS
125Identifies the root filesystem.
126.It Dv ST_EXRDONLY
127The filesystem is exported read-only.
128.It Dv ST_EXPORTED
129The filesystem is exported for both reading and writing.
130.It Dv ST_DEFEXPORTED
131The filesystem is exported for both reading and writing to any Internet host.
132.It Dv ST_EXPORTANON
133The filesystem maps all remote accesses to the anonymous user.
134.It Dv ST_EXKERB
135The filesystem is exported with Kerberos uid mapping.
136.It Dv ST_EXNORESPORT
137Don't enforce reserved ports (NFS).
138.It Dv ST_EXPUBLIC
139Public export (WebNFS).
140.El
141.Pp
142Fields that are undefined for a particular file system are set to \-1.
143.Sh NOTES
144.Bl -tag -width f_bavail
145.It f_flag
146The
147.Fa f_flag
148field is the same as the
149.Fa f_flags
150field in the
151.Bx 4.3
152.Xr statfs 2
153system call.
154.It f_fsid
155Is defined to be
156.Ft unsigned long
157by the X/Open standard.
158Unfortunately this is not enough space to store our
159.Ft fsid_t ,
160so we define an additional
161.Fa f_fsidx
162field.
163.It f_bavail
164Could historically be negative (in the
165.Xr statfs 2
166system call) when the used space has exceeded
167the non-superuser free space.
168In order to comply with the X/Open standard, we have to define
169.Ft fsblkcnt_t
170as an unsigned type, so in all cases where
171.Fa f_bavail
172would have been negative, we set it to 0.
173In addition we provide
174.Fa f_bresvd
175which contains the amount of reserved blocks for the superuser, so
176the old value of
177.Fa f_bavail
178can be easily computed as:
179.Bd -literal
180	old_bavail = f_bfree - f_bresvd;
181.Ed
182.El
183.Sh SEE ALSO
184.Xr statvfs 2
185.Sh HISTORY
186The
187.In sys/statvfs.h
188header first appeared in
189.Nx 3.0 .
190