freebsd-skq/share/man/man9/vfs_getnewfsid.9
Alfred Perlstein ffc0b97fd0 More kernel vfs docco.
Xref vfs_mount(9) from vfs_mount(9)

Submitted by: Chad David <davidc@acns.ab.ca>
PR: docs/32431
2001-12-03 00:25:04 +00:00

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.\"
.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.\" $FreeBSD$
.\"
.Dd November 21, 2001
.Dt VFS_GETNEWFSID 9
.Os
.Sh NAME
.Nm vfs_getnewfsid
.Nd "allocate a new fsid"
.Sh SYNOPSIS
.In sys/param.h
.In sys/mount.h
.Ft void
.Fn vfs_getnewfsid "struct mount *mp"
.Sh DESCRIPTION
The
.Fn vfs_getnewfsid
function allocates a new filesystem identifier for the mount point given.
Filesystems typically call
.Fn vfs_getnewfsid
in their mount routine in order to acquire a unique id within the system
which can later be used to uniquely identify the filesystem via calls such as
.Fn vfs_getvfs .
.Pp
The actual fsid is made up of two 32 bit integers, that are stored in the statfs
structure of
.Fa mp .
The first integer is unique in the set of mounted filesystems, while the second holds
the filesystem type.
.Bd -literal
typedef struct fsid {
int32_t val[2];
} fsid_t;
.Ed
.Sh PSEUDOCODE
.Bd -literal
xxx_mount(struct mount *mp, char *path, caddr_t data, struct nameidata *ndp, struct thread *td)
{
...
vfs_getnewfsid(mp);
...
}
.Ed
.Sh SEE ALSO
.Xr vfs_getvfs 9
.Sh AUTHORS
This man page was written by
.An Chad David Aq davidc@acns.ab.ca .