57b4252e45
namei(9). Based on the submission by rdivacky, sponsored by Google Summer of Code 2007 Reviewed by: rwatson, rdivacky Tested by: pho
372 lines
8.7 KiB
C
372 lines
8.7 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/fcntl.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_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)) {
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VOP_UNLOCK(mp->mnt_vnodecovered, 0);
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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))
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vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
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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);
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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);
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if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
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MNT_ILOCK(mp);
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mp->mnt_flag |= MNT_LOCAL;
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MNT_IUNLOCK(mp);
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}
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MNT_ILOCK(mp);
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mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE;
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MNT_IUNLOCK(mp);
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mp->mnt_data = 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))
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panic("root vnode is locked.\n");
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#endif
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vn_lock(vp, flags | LK_RETRY);
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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_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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};
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VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);
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