freebsd-nq/share/man/man9/vfs_busy.9
Alfred Perlstein 8981fef84c Document kernel API for vfs_busy(), vfs_mount(), vfs_unbusy(), and
vinvalbuf().

Submitted by: Chad David <davidc@acns.ab.ca>
2001-07-09 06:47:10 +00:00

81 lines
2.8 KiB
Groff

.\"
.\" 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 July 8, 2001
.Dt VFS_BUSY 9
.Os
.Sh NAME
.Nm vfs_busy
.Nd "Marks a mount point as busy."
.Sh SYNOPSIS
.Ft int
.Fo vfs_busy
.Fa "struct mount *mp"
.Fa "int flags"
.Fa "struct mtx *interlkp"
.Fa "struct proc *p"
.Fc
.Sh DESCRIPTION
The
.Nm
function marks a mount point as busy. The purpose of this
function is to synchronize access to a mount point. It also
delays unmounting by sleeping on mp if the MNTK_UNMOUNT flag
is set in mp->mnt_kern_flag and the LK_NOWAIT flag is NOT set.
.Pp
Its arguments are:
.Bl -tag -width interlkp
.It Ar mp
The mount point to busy.
.It Ar flags
Flags controlling the operation of
.Nm
.
.Pp
LK_NOWAIT - do not sleep if MNTK_UNMOUNT is set.
.It Ar interlkp
The interlock mutex for mp->mount_lock. If there is any chance
the mount point is being unmounted and LK_NOWAIT is not set then
interlock must be valid locked mutex.
.It Ar p
The process responsible for this call.
.El
.Sh LOCKS
If interlkp is a valid pointer it must be locked on entry,
and it will not be unlocked even on error.
.Sh RETURN VALUES
A 0 value is returned on success. If the mount point is being
unmounted ENOENT will always be returned.
.Sh ERRORS
.Bl -tag
.It Bq ENOENT
The mount point is being unmounted (MNTK_UNMOUNT is set).
.El
.Sh AUTHORS
This man page was written by Chad David.