xref: /freebsd/share/man/man9/vfs_getnewfsid.9 (revision fa9896e082a1046ff4fbc75fcba4d18d1f2efc19)
1ffc0b97fSAlfred Perlstein.\"
2ffc0b97fSAlfred Perlstein.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
3ffc0b97fSAlfred Perlstein.\"
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6ffc0b97fSAlfred Perlstein.\" are met:
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10ffc0b97fSAlfred Perlstein.\"    addition of one or more copyright notices.
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27ffc0b97fSAlfred Perlstein.Dd November 21, 2001
28ffc0b97fSAlfred Perlstein.Dt VFS_GETNEWFSID 9
29ffc0b97fSAlfred Perlstein.Os
30ffc0b97fSAlfred Perlstein.Sh NAME
31ffc0b97fSAlfred Perlstein.Nm vfs_getnewfsid
321f620c2eSRuslan Ermilov.Nd "allocate a new file system identifier"
33ffc0b97fSAlfred Perlstein.Sh SYNOPSIS
34ffc0b97fSAlfred Perlstein.In sys/param.h
35ffc0b97fSAlfred Perlstein.In sys/mount.h
36ffc0b97fSAlfred Perlstein.Ft void
37ffc0b97fSAlfred Perlstein.Fn vfs_getnewfsid "struct mount *mp"
38ffc0b97fSAlfred Perlstein.Sh DESCRIPTION
39ffc0b97fSAlfred PerlsteinThe
40ffc0b97fSAlfred Perlstein.Fn vfs_getnewfsid
41ffc0b97fSAlfred Perlsteinfunction allocates a new file system identifier for the mount point given.
42ffc0b97fSAlfred PerlsteinFile systems typically call
43ffc0b97fSAlfred Perlstein.Fn vfs_getnewfsid
441f620c2eSRuslan Ermilovin their mount routine in order to acquire a unique ID within the system
45ffc0b97fSAlfred Perlsteinwhich can later be used to uniquely identify the file system via calls such as
461f620c2eSRuslan Ermilov.Xr vfs_getvfs 9 .
47ffc0b97fSAlfred Perlstein.Pp
481f620c2eSRuslan ErmilovThe actual
491f620c2eSRuslan Ermilov.Vt fsid
501f620c2eSRuslan Ermilovis made up of two 32 bit integers, that are stored in the
511f620c2eSRuslan Ermilov.Vt statfs
52ffc0b97fSAlfred Perlsteinstructure of
53ffc0b97fSAlfred Perlstein.Fa mp .
541f620c2eSRuslan ErmilovThe first integer is unique in the set of mounted file systems,
551f620c2eSRuslan Ermilovwhile the second holds the file system type.
56ffc0b97fSAlfred Perlstein.Bd -literal
57ffc0b97fSAlfred Perlsteintypedef	struct fsid {
58ffc0b97fSAlfred Perlstein	int32_t val[2];
59ffc0b97fSAlfred Perlstein} fsid_t;
60ffc0b97fSAlfred Perlstein.Ed
61ffc0b97fSAlfred Perlstein.Sh PSEUDOCODE
62ffc0b97fSAlfred Perlstein.Bd -literal
631f620c2eSRuslan Ermilovxxx_mount(struct mount *mp, char *path, caddr_t data,
641f620c2eSRuslan Ermilov	struct nameidata *ndp, struct thread *td)
65ffc0b97fSAlfred Perlstein{
66ffc0b97fSAlfred Perlstein	...
67ffc0b97fSAlfred Perlstein	vfs_getnewfsid(mp);
68ffc0b97fSAlfred Perlstein	...
69ffc0b97fSAlfred Perlstein}
70ffc0b97fSAlfred Perlstein.Ed
71ffc0b97fSAlfred Perlstein.Sh SEE ALSO
72ffc0b97fSAlfred Perlstein.Xr vfs_getvfs 9
73ffc0b97fSAlfred Perlstein.Sh AUTHORS
7409356c84SHiten PandyaThis manual page was written by
75*8a7314fcSBaptiste Daroussin.An Chad David Aq Mt davidc@acns.ab.ca .
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