xref: /freebsd/share/man/man9/vfs_getnewfsid.9 (revision ffc0b97fd087519392b19a9d43056d7099b831eb)
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2.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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27.\" $FreeBSD$
28.\"
29.Dd November 21, 2001
30.Dt VFS_GETNEWFSID 9
31.Os
32.Sh NAME
33.Nm vfs_getnewfsid
34.Nd "allocate a new fsid"
35.Sh SYNOPSIS
36.In sys/param.h
37.In sys/mount.h
38.Ft void
39.Fn vfs_getnewfsid "struct mount *mp"
40.Sh DESCRIPTION
41The
42.Fn vfs_getnewfsid
43function allocates a new filesystem identifier for the mount point given.
44Filesystems typically call
45.Fn vfs_getnewfsid
46in their mount routine in order to acquire a unique id within the system
47which can later be used to uniquely identify the filesystem via calls such as
48.Fn vfs_getvfs .
49.Pp
50The actual fsid is made up of two 32 bit integers, that are stored in the statfs
51structure of
52.Fa mp .
53The first integer is unique in the set of mounted filesystems, while the second holds
54the filesystem type.
55.Bd -literal
56	typedef	struct fsid {
57		int32_t val[2];
58	} fsid_t;
59.Ed
60.Sh PSEUDOCODE
61.Bd -literal
62	xxx_mount(struct mount *mp, char *path, caddr_t data, struct nameidata *ndp, struct thread *td)
63	{
64		...
65		vfs_getnewfsid(mp);
66		...
67	}
68.Ed
69.Sh SEE ALSO
70.Xr vfs_getvfs 9
71.Sh AUTHORS
72This man page was written by
73.An Chad David Aq davidc@acns.ab.ca .
74