78 lines
2.6 KiB
Groff
78 lines
2.6 KiB
Groff
.\"
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.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 21, 2001
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.Dt VFS_GETNEWFSID 9
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.Os
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.Sh NAME
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.Nm vfs_getnewfsid
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.Nd "allocate a new file system identifier"
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/mount.h
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.Ft void
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.Fn vfs_getnewfsid "struct mount *mp"
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.Sh DESCRIPTION
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The
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.Fn vfs_getnewfsid
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function allocates a new file system identifier for the mount point given.
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File systems typically call
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.Fn vfs_getnewfsid
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in their mount routine in order to acquire a unique ID within the system
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which can later be used to uniquely identify the file system via calls such as
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.Xr vfs_getvfs 9 .
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.Pp
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The actual
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.Vt fsid
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is made up of two 32 bit integers, that are stored in the
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.Vt statfs
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structure of
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.Fa mp .
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The first integer is unique in the set of mounted file systems,
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while the second holds the file system type.
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.Bd -literal
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typedef struct fsid {
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int32_t val[2];
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} fsid_t;
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.Ed
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.Sh PSEUDOCODE
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.Bd -literal
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xxx_mount(struct mount *mp, char *path, caddr_t data,
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struct nameidata *ndp, struct thread *td)
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{
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...
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vfs_getnewfsid(mp);
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...
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}
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.Ed
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.Sh SEE ALSO
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.Xr vfs_getvfs 9
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.Sh AUTHORS
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This manual page was written by
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.An Chad David Aq davidc@acns.ab.ca .
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