vfs_busy(9)

NAME

vfs_busy - marks a mount point as busy

SYNOPSIS

#include <sys/param.h>
#include <sys/mount.h>
int
vfs_busy(struct mount *mp, int flags, struct mtx *interlkp,
        struct thread *td);

DESCRIPTION

The vfs_busy() 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.

Its arguments are:

mp The mount point to busy.

flags Flags controlling how vfs_busy() should act.

LK_NOWAIT do not sleep if MNTK_UNMOUNT is

set.

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.

td The thread responsible for this call.

LOCKS

If interlkp is a valid pointer it must be locked on entry,

and it will
not be unlocked even in the case of an error.

RETURN VALUES

A 0 value is returned on success. If the mount point is be

ing unmounted
ENOENT will always be returned.

ERRORS

[ENOENT] The mount point is being unmounted (MN

TK_UNMOUNT is

set).

AUTHORS

This manual page was written by Chad David <davidc@ac

ns.ab.ca>.

BSD July 8, 2001

BSD