freebsd-dev/sys/fs/devfs/devfs_vfsops.c
Poul-Henning Kamp 93bcdfe270 Add refcounts to the "global" DEVFS inode slots, this allows us
to recycle inodes after a destroy_dev() but not until all mounts
have picked up the change.

Add support for an overflow table for DEVFS inodes.  The static
table defaults to 1024 inodes, if that fills, an overflow table
of 32k inodes is allocated.  Both numbers can be changed at
compile time, the size of the overflow table also with the
sysctl vfs.devfs.noverflow.

Use atomic instructions to barrier between make_dev()/destroy_dev()
and the mounts.

Add lockmgr() locking of directories for operations accessing or
modifying the directory TAILQs.

Various nitpicking here and there.
2000-09-06 11:26:43 +00:00

213 lines
5.2 KiB
C

/*
* Copyright (c) 1992, 1993, 1995
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2000
* Poul-Henning Kamp. All rights reserved.
*
* This code is derived from software donated to Berkeley by
* Jan-Simon Pendry.
*
* 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, this list of conditions and the following disclaimer.
* 2. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*
* @(#)kernfs_vfsops.c 8.10 (Berkeley) 5/14/95
* From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
*
* $FreeBSD$
*/
#include "opt_devfs.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <fs/devfs/devfs.h>
MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
static int devfs_mount __P((struct mount *mp, char *path, caddr_t data,
struct nameidata *ndp, struct proc *p));
static int devfs_unmount __P((struct mount *mp, int mntflags,
struct proc *p));
static int devfs_root __P((struct mount *mp, struct vnode **vpp));
static int devfs_statfs __P((struct mount *mp, struct statfs *sbp,
struct proc *p));
/*
* Mount the filesystem
*/
static int
devfs_mount(mp, path, data, ndp, p)
struct mount *mp;
char *path;
caddr_t data;
struct nameidata *ndp;
struct proc *p;
{
int error;
u_int size;
struct devfs_mount *fmp;
struct vnode *rvp;
error = 0;
/*
* XXX: flag changes.
*/
if (mp->mnt_flag & MNT_UPDATE)
return (EOPNOTSUPP);
MALLOC(fmp, struct devfs_mount *, sizeof(struct devfs_mount),
M_DEVFS, M_WAITOK);
bzero(fmp, sizeof(*fmp));
lockinit(&fmp->dm_lock, PVFS, "devfs", 0, LK_NOPAUSE);
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_data = (qaddr_t) fmp;
vfs_getnewfsid(mp);
fmp->dm_inode = DEVFSINOMOUNT;
fmp->dm_rootdir = devfs_vmkdir("(root)", 6, NULL);
fmp->dm_rootdir->de_inode = 2;
fmp->dm_basedir = fmp->dm_rootdir;
error = devfs_root(mp, &rvp);
if (error) {
FREE(fmp, M_DEVFS);
return (error);
}
VOP_UNLOCK(rvp, 0, p);
if (path != NULL) {
(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
} else {
strcpy(mp->mnt_stat.f_mntonname, "/");
size = 1;
}
bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
bcopy("devfs", mp->mnt_stat.f_mntfromname, sizeof("devfs"));
(void)devfs_statfs(mp, &mp->mnt_stat, p);
return (0);
}
static int
devfs_unmount(mp, mntflags, p)
struct mount *mp;
int mntflags;
struct proc *p;
{
int error;
int flags = 0;
struct vnode *rootvp;
struct devfs_mount *fmp;
error = devfs_root(mp, &rootvp);
if (error)
return (error);
fmp = VFSTODEVFS(mp);
if (mntflags & MNT_FORCE)
flags |= FORCECLOSE;
if (rootvp->v_usecount > 1)
return (EBUSY);
devfs_purge(fmp->dm_rootdir);
error = vflush(mp, rootvp, flags);
if (error)
return (error);
vput(rootvp);
vrele(rootvp);
vgone(rootvp);
mp->mnt_data = 0;
free(fmp, M_DEVFS);
return 0;
}
/* Return locked reference to root. */
static int
devfs_root(mp, vpp)
struct mount *mp;
struct vnode **vpp;
{
int error;
struct proc *p;
struct vnode *vp;
struct devfs_mount *dmp;
p = curproc; /* XXX */
dmp = VFSTODEVFS(mp);
error = devfs_allocv(dmp->dm_rootdir, mp, &vp, p);
if (error)
return (error);
vp->v_flag |= VROOT;
*vpp = vp;
return (0);
}
static int
devfs_statfs(mp, sbp, p)
struct mount *mp;
struct statfs *sbp;
struct proc *p;
{
sbp->f_flags = 0;
sbp->f_bsize = DEV_BSIZE;
sbp->f_iosize = DEV_BSIZE;
sbp->f_blocks = 2; /* 1K to keep df happy */
sbp->f_bfree = 0;
sbp->f_bavail = 0;
sbp->f_files = 0;
sbp->f_ffree = 0;
if (sbp != &mp->mnt_stat) {
sbp->f_type = mp->mnt_vfc->vfc_typenum;
bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
}
return (0);
}
static struct vfsops devfs_vfsops = {
devfs_mount,
vfs_stdstart,
devfs_unmount,
devfs_root,
vfs_stdquotactl,
devfs_statfs,
vfs_stdsync,
vfs_stdvget,
vfs_stdfhtovp,
vfs_stdcheckexp,
vfs_stdvptofh,
vfs_stdinit,
vfs_stduninit,
vfs_stdextattrctl,
};
VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC);