05c0f5c1e2
will allow the NFS server to call vfs_stdcheckexp() on the exported nullfs filesystem, not the underlying filesystem being nullfs mounted. If the lower filesystem was not NFS exported, then the NFS exported null filesystem would not work. Pointed out by: scottl PR: kern/87906 MFC after: 1 week
383 lines
9.0 KiB
C
383 lines
9.0 KiB
C
/*-
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* Copyright (c) 1992, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software donated to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
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*
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* @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
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* $FreeBSD$
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*/
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/*
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* Null Layer
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* (See null_vnops.c for a description of what this does.)
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kdb.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <fs/nullfs/null.h>
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static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure");
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static vfs_fhtovp_t nullfs_fhtovp;
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static vfs_mount_t nullfs_mount;
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static vfs_quotactl_t nullfs_quotactl;
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static vfs_root_t nullfs_root;
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static vfs_sync_t nullfs_sync;
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static vfs_statfs_t nullfs_statfs;
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static vfs_unmount_t nullfs_unmount;
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static vfs_vget_t nullfs_vget;
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static vfs_vptofh_t nullfs_vptofh;
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static vfs_extattrctl_t nullfs_extattrctl;
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/*
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* Mount null layer
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*/
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static int
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nullfs_mount(struct mount *mp, struct thread *td)
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{
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int error = 0;
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struct vnode *lowerrootvp, *vp;
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struct vnode *nullm_rootvp;
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struct null_mount *xmp;
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char *target;
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int isvnunlocked = 0, len;
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struct nameidata nd, *ndp = &nd;
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NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
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if (mp->mnt_flag & MNT_ROOTFS)
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return (EOPNOTSUPP);
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/*
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* Update is a no-op
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*/
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if (mp->mnt_flag & MNT_UPDATE) {
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/*
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* Only support update mounts for NFS export.
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*/
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if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
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return (0);
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else
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return (EOPNOTSUPP);
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}
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/*
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* Get argument
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*/
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error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
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if (error || target[len - 1] != '\0')
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return (EINVAL);
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/*
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* Unlock lower node to avoid deadlock.
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* (XXX) VOP_ISLOCKED is needed?
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*/
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if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
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VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
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VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
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isvnunlocked = 1;
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}
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/*
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* Find lower node
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*/
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NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF,
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UIO_SYSSPACE, target, td);
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error = namei(ndp);
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/*
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* Re-lock vnode.
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*/
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if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
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vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
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if (error)
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return (error);
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NDFREE(ndp, NDF_ONLY_PNBUF);
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/*
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* Sanity check on lower vnode
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*/
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lowerrootvp = ndp->ni_vp;
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/*
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* Check multi null mount to avoid `lock against myself' panic.
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*/
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if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
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NULLFSDEBUG("nullfs_mount: multi null mount?\n");
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vput(lowerrootvp);
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return (EDEADLK);
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}
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xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
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M_NULLFSMNT, M_WAITOK); /* XXX */
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/*
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* Save reference to underlying FS
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*/
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xmp->nullm_vfs = lowerrootvp->v_mount;
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/*
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* Save reference. Each mount also holds
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* a reference on the root vnode.
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*/
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error = null_nodeget(mp, lowerrootvp, &vp);
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/*
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* Make sure the node alias worked
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*/
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if (error) {
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VOP_UNLOCK(vp, 0, td);
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vrele(lowerrootvp);
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free(xmp, M_NULLFSMNT); /* XXX */
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return (error);
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}
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/*
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* Keep a held reference to the root vnode.
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* It is vrele'd in nullfs_unmount.
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*/
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nullm_rootvp = vp;
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nullm_rootvp->v_vflag |= VV_ROOT;
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xmp->nullm_rootvp = nullm_rootvp;
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/*
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* Unlock the node (either the lower or the alias)
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*/
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VOP_UNLOCK(vp, 0, td);
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if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
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mp->mnt_flag |= MNT_LOCAL;
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mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE;
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mp->mnt_data = (qaddr_t) xmp;
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vfs_getnewfsid(mp);
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vfs_mountedfrom(mp, target);
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NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
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mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
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return (0);
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}
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/*
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* Free reference to null layer
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*/
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static int
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nullfs_unmount(mp, mntflags, td)
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struct mount *mp;
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int mntflags;
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struct thread *td;
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{
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void *mntdata;
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int error;
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int flags = 0;
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NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
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if (mntflags & MNT_FORCE)
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flags |= FORCECLOSE;
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/* There is 1 extra root vnode reference (nullm_rootvp). */
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error = vflush(mp, 1, flags, td);
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if (error)
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return (error);
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/*
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* Finally, throw away the null_mount structure
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*/
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mntdata = mp->mnt_data;
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mp->mnt_data = 0;
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free(mntdata, M_NULLFSMNT);
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return 0;
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}
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static int
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nullfs_root(mp, flags, vpp, td)
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struct mount *mp;
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int flags;
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struct vnode **vpp;
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struct thread *td;
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{
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struct vnode *vp;
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NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
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(void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
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(void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
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/*
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* Return locked reference to root.
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*/
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vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
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VREF(vp);
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#ifdef NULLFS_DEBUG
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if (VOP_ISLOCKED(vp, NULL)) {
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kdb_enter("root vnode is locked.\n");
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vrele(vp);
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return (EDEADLK);
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}
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#endif
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vn_lock(vp, flags | LK_RETRY, td);
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*vpp = vp;
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return 0;
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}
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static int
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nullfs_quotactl(mp, cmd, uid, arg, td)
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struct mount *mp;
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int cmd;
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uid_t uid;
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void *arg;
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struct thread *td;
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{
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return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
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}
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static int
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nullfs_statfs(mp, sbp, td)
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struct mount *mp;
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struct statfs *sbp;
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struct thread *td;
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{
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int error;
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struct statfs mstat;
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NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
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(void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
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(void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
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bzero(&mstat, sizeof(mstat));
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error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
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if (error)
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return (error);
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/* now copy across the "interesting" information and fake the rest */
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sbp->f_type = mstat.f_type;
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sbp->f_flags = mstat.f_flags;
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sbp->f_bsize = mstat.f_bsize;
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sbp->f_iosize = mstat.f_iosize;
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sbp->f_blocks = mstat.f_blocks;
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sbp->f_bfree = mstat.f_bfree;
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sbp->f_bavail = mstat.f_bavail;
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sbp->f_files = mstat.f_files;
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sbp->f_ffree = mstat.f_ffree;
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return (0);
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}
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static int
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nullfs_sync(mp, waitfor, td)
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struct mount *mp;
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int waitfor;
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struct thread *td;
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{
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/*
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* XXX - Assumes no data cached at null layer.
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*/
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return (0);
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}
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static int
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nullfs_vget(mp, ino, flags, vpp)
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struct mount *mp;
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ino_t ino;
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int flags;
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struct vnode **vpp;
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{
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int error;
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error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
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if (error)
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return (error);
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return (null_nodeget(mp, *vpp, vpp));
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}
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static int
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nullfs_fhtovp(mp, fidp, vpp)
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struct mount *mp;
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struct fid *fidp;
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struct vnode **vpp;
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{
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int error;
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error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
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if (error)
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return (error);
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return (null_nodeget(mp, *vpp, vpp));
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}
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static int
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nullfs_vptofh(vp, fhp)
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struct vnode *vp;
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struct fid *fhp;
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{
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struct vnode *lvp;
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lvp = NULLVPTOLOWERVP(vp);
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return VFS_VPTOFH(lvp, fhp);
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}
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static int
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nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td)
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struct mount *mp;
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int cmd;
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struct vnode *filename_vp;
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int namespace;
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const char *attrname;
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struct thread *td;
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{
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return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
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namespace, attrname, td);
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}
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static struct vfsops null_vfsops = {
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.vfs_extattrctl = nullfs_extattrctl,
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.vfs_fhtovp = nullfs_fhtovp,
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.vfs_init = nullfs_init,
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.vfs_mount = nullfs_mount,
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.vfs_quotactl = nullfs_quotactl,
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.vfs_root = nullfs_root,
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.vfs_statfs = nullfs_statfs,
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.vfs_sync = nullfs_sync,
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.vfs_uninit = nullfs_uninit,
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.vfs_unmount = nullfs_unmount,
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.vfs_vget = nullfs_vget,
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.vfs_vptofh = nullfs_vptofh,
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};
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VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);
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