usr/src/sys/miscfs/nullfs/null_vfsops.c

/*
 * Copyright (c) 1992, 1993, 1995
 *      The Regents of the University of California.  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. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 *
 *      @(#)null_vfsops.c       8.7 (Berkeley) 5/14/95
 *
 * @(#)lofs_vfsops.c    1.2 (Berkeley) 6/18/92
 * $Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp jsp $
 */

/*
 * Null Layer
 * (See null_vnops.c for a description of what this does.)
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <miscfs/nullfs/null.h>

/*
 * Mount null layer
 */
int
nullfs_mount(mp, path, data, ndp, p)
        struct mount *mp;
        char *path;
        caddr_t data;
        struct nameidata *ndp;
        struct proc *p;
{
        int error = 0;
        struct null_args args;
        struct vnode *lowerrootvp, *vp;
        struct vnode *nullm_rootvp;
        struct null_mount *xmp;
        u_int size;

#ifdef NULLFS_DIAGNOSTIC
        printf("nullfs_mount(mp = %x)\n", mp);
#endif

        /*
         * Update is a no-op
         */
        if (mp->mnt_flag & MNT_UPDATE) {
                return (EOPNOTSUPP);
                /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
        }

        /*
         * Get argument
         */
        if (error = copyin(data, (caddr_t)&args, sizeof(struct null_args)))
                return (error);

        /*
         * Find lower node
         */
        NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
                UIO_USERSPACE, args.target, p);
        if (error = namei(ndp))
                return (error);

        /*
         * Sanity check on lower vnode
         */
        lowerrootvp = ndp->ni_vp;

        vrele(ndp->ni_dvp);
        ndp->ni_dvp = NULL;

        xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
                                M_UFSMNT, M_WAITOK);    /* XXX */

        /*
         * Save reference to underlying FS
         */
        xmp->nullm_vfs = lowerrootvp->v_mount;

        /*
         * Save reference.  Each mount also holds
         * a reference on the root vnode.
         */
        error = null_node_create(mp, lowerrootvp, &vp);
        /*
         * Unlock the node (either the lower or the alias)
         */
        VOP_UNLOCK(vp, 0, p);
        /*
         * Make sure the node alias worked
         */
        if (error) {
                vrele(lowerrootvp);
                free(xmp, M_UFSMNT);    /* XXX */
                return (error);
        }

        /*
         * Keep a held reference to the root vnode.
         * It is vrele'd in nullfs_unmount.
         */
        nullm_rootvp = vp;
        nullm_rootvp->v_flag |= VROOT;
        xmp->nullm_rootvp = nullm_rootvp;
        if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
                mp->mnt_flag |= MNT_LOCAL;
        mp->mnt_data = (qaddr_t) xmp;
        vfs_getnewfsid(mp);

        (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
        bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
        (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
            &size);
        bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
#ifdef NULLFS_DIAGNOSTIC
        printf("nullfs_mount: lower %s, alias at %s\n",
                mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
#endif
        return (0);
}

/*
 * VFS start.  Nothing needed here - the start routine
 * on the underlying filesystem will have been called
 * when that filesystem was mounted.
 */
int
nullfs_start(mp, flags, p)
        struct mount *mp;
        int flags;
        struct proc *p;
{
        return (0);
        /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
}

/*
 * Free reference to null layer
 */
int
nullfs_unmount(mp, mntflags, p)
        struct mount *mp;
        int mntflags;
        struct proc *p;
{
        struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
        int error;
        int flags = 0;

#ifdef NULLFS_DIAGNOSTIC
        printf("nullfs_unmount(mp = %x)\n", mp);
#endif

        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;

        /*
         * Clear out buffer cache.  I don't think we
         * ever get anything cached at this level at the
         * moment, but who knows...
         */
#if 0
        mntflushbuf(mp, 0);
        if (mntinvalbuf(mp, 1))
                return (EBUSY);
#endif
        if (nullm_rootvp->v_usecount > 1)
                return (EBUSY);
        if (error = vflush(mp, nullm_rootvp, flags))
                return (error);

#ifdef NULLFS_DIAGNOSTIC
        vprint("alias root of lower", nullm_rootvp);
#endif
        /*
         * Release reference on underlying root vnode
         */
        vrele(nullm_rootvp);
        /*
         * And blow it away for future re-use
         */
        vgone(nullm_rootvp);
        /*
         * Finally, throw away the null_mount structure
         */
        free(mp->mnt_data, M_UFSMNT);   /* XXX */
        mp->mnt_data = 0;
        return 0;
}

int
nullfs_root(mp, vpp)
        struct mount *mp;
        struct vnode **vpp;
{
        struct proc *p = curproc;       /* XXX */
        struct vnode *vp;

#ifdef NULLFS_DIAGNOSTIC
        printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp,
                        MOUNTTONULLMOUNT(mp)->nullm_rootvp,
                        NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
                        );
#endif

        /*
         * Return locked reference to root.
         */
        vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
        VREF(vp);
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
        *vpp = vp;
        return 0;
}

int
nullfs_quotactl(mp, cmd, uid, arg, p)
        struct mount *mp;
        int cmd;
        uid_t uid;
        caddr_t arg;
        struct proc *p;
{
        return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
}

int
nullfs_statfs(mp, sbp, p)
        struct mount *mp;
        struct statfs *sbp;
        struct proc *p;
{
        int error;
        struct statfs mstat;

#ifdef NULLFS_DIAGNOSTIC
        printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp,
                        MOUNTTONULLMOUNT(mp)->nullm_rootvp,
                        NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
                        );
#endif

        bzero(&mstat, sizeof(mstat));

        error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p);
        if (error)
                return (error);

        /* now copy across the "interesting" information and fake the rest */
        sbp->f_type = mstat.f_type;
        sbp->f_flags = mstat.f_flags;
        sbp->f_bsize = mstat.f_bsize;
        sbp->f_iosize = mstat.f_iosize;
        sbp->f_blocks = mstat.f_blocks;
        sbp->f_bfree = mstat.f_bfree;
        sbp->f_bavail = mstat.f_bavail;
        sbp->f_files = mstat.f_files;
        sbp->f_ffree = mstat.f_ffree;
        if (sbp != &mp->mnt_stat) {
                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);
}

int
nullfs_sync(mp, waitfor, cred, p)
        struct mount *mp;
        int waitfor;
        struct ucred *cred;
        struct proc *p;
{
        /*
         * XXX - Assumes no data cached at null layer.
         */
        return (0);
}

int
nullfs_vget(mp, ino, vpp)
        struct mount *mp;
        ino_t ino;
        struct vnode **vpp;
{

        return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
}

int
nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
        struct mount *mp;
        struct fid *fidp;
        struct mbuf *nam;
        struct vnode **vpp;
        int *exflagsp;
        struct ucred**credanonp;
{

        return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp);
}

int
nullfs_vptofh(vp, fhp)
        struct vnode *vp;
        struct fid *fhp;
{
        return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
}

int nullfs_init __P((struct vfsconf *));

#define nullfs_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \
            size_t, struct proc *)))eopnotsupp)

struct vfsops null_vfsops = {
        nullfs_mount,
        nullfs_start,
        nullfs_unmount,
        nullfs_root,
        nullfs_quotactl,
        nullfs_statfs,
        nullfs_sync,
        nullfs_vget,
        nullfs_fhtovp,
        nullfs_vptofh,
        nullfs_init,
        nullfs_sysctl,
};