More kernel vfs docco.

Xref vfs_mount(9) from vfs_mount(9)

Submitted by: Chad David <davidc@acns.ab.ca>
PR: docs/32431

1 files changed, 75 insertions, 0 deletions

diff --git a/share/man/man9/vfs_mountedon.9 b/share/man/man9/vfs_mountedon.9
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+.\"
+.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer as
+.\"    the first lines of this file unmodified other than the possible
+.\"    addition of one or more copyright notices.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice(s), this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+.\" DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+.\" DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 21, 2001
+.Dt VFS_MOUNTEDON 9
+.Os
+.Sh NAME
+.Nm vfs_mountedon
+.Nd "check if the vnode belongs to a mounted filesystem"
+.Sh SYNOPSIS
+.In sys/param.h
+.In sys/vnode.h
+.Ft int
+.Fn vfs_mountedon "struct vnode *vp"
+.Sh DESCRIPTION
+.Fn vfs_mountedon
+inspects the mount structure in
+.Fa vp
+to determine if it points to a valid mount point.
+If the mount is valid the vnode is considered to be busy.
+.Pp
+A common use of
+.Fn vfs_mountedon
+it to call it on device vnodes to determine if they are already associated with
+a filesystem.
+This is done to prevent multiple mounts on the same device.
+.Sh RETURN VALUES
+.Dv EBUSY
+is returned if the vnode has a valid mount point; otherwise, 0 is returned.
+.Sh PSEUDOCODE
+.Bd -literal
+	int
+	ffs_mountfs(devvp, mp, td, malloctype)
+		register struct vnode *devvp;
+		struct mount *mp;
+		struct thread *td;
+		struct malloc_type *malloctype;
+	{
+		...
+
+		error = vfs_mountedon(devvp);
+		if (error)  
+			return (error);
+
+		...
+	}
+.Ed
+.Sh AUTHORS
+This man page was written by
+.An Chad David Aq davidc@acns.ab.ca .