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-rw-r--r--sys/fs/nullfs/null.h76
-rw-r--r--sys/fs/nullfs/null_subr.c301
-rw-r--r--sys/fs/nullfs/null_vfsops.c450
-rw-r--r--sys/fs/nullfs/null_vnops.c610
4 files changed, 1437 insertions, 0 deletions
diff --git a/sys/fs/nullfs/null.h b/sys/fs/nullfs/null.h
new file mode 100644
index 0000000..fcd179e
--- /dev/null
+++ b/sys/fs/nullfs/null.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 1992, 1993
+ * 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.h 8.3 (Berkeley) 8/20/94
+ *
+ * $FreeBSD$
+ */
+
+struct null_args {
+ char *target; /* Target of loopback */
+};
+
+struct null_mount {
+ struct mount *nullm_vfs;
+ struct vnode *nullm_rootvp; /* Reference to root null_node */
+};
+
+#ifdef KERNEL
+/*
+ * A cache of vnode references
+ */
+struct null_node {
+ LIST_ENTRY(null_node) null_hash; /* Hash list */
+ struct vnode *null_lowervp; /* VREFed once */
+ struct vnode *null_vnode; /* Back pointer */
+};
+
+extern int nullfs_init __P((struct vfsconf *vfsp));
+extern int null_node_create __P((struct mount *mp, struct vnode *target, struct vnode **vpp));
+
+#define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
+#define VTONULL(vp) ((struct null_node *)(vp)->v_data)
+#define NULLTOV(xp) ((xp)->null_vnode)
+#ifdef DIAGNOSTIC
+extern struct vnode *null_checkvp __P((struct vnode *vp, char *fil, int lno));
+#define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
+#else
+#define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
+#endif
+
+extern int null_bypass __P((struct vop_generic_args *ap));
+
+extern vop_t **null_vnodeop_p;
+#endif /* KERNEL */
diff --git a/sys/fs/nullfs/null_subr.c b/sys/fs/nullfs/null_subr.c
new file mode 100644
index 0000000..ad37a1e
--- /dev/null
+++ b/sys/fs/nullfs/null_subr.c
@@ -0,0 +1,301 @@
+/*
+ * Copyright (c) 1992, 1993
+ * 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_subr.c 8.7 (Berkeley) 5/14/95
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/vnode.h>
+#include <sys/mount.h>
+#include <sys/malloc.h>
+#include <miscfs/nullfs/null.h>
+
+#define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
+#define NNULLNODECACHE 16
+
+/*
+ * Null layer cache:
+ * Each cache entry holds a reference to the lower vnode
+ * along with a pointer to the alias vnode. When an
+ * entry is added the lower vnode is VREF'd. When the
+ * alias is removed the lower vnode is vrele'd.
+ */
+
+#define NULL_NHASH(vp) \
+ (&null_node_hashtbl[(((uintptr_t)vp)>>LOG2_SIZEVNODE) & null_node_hash])
+static LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
+static u_long null_node_hash;
+
+static int null_node_alloc __P((struct mount *mp, struct vnode *lowervp,
+ struct vnode **vpp));
+static struct vnode *
+ null_node_find __P((struct mount *mp, struct vnode *lowervp));
+
+/*
+ * Initialise cache headers
+ */
+int
+nullfs_init(vfsp)
+ struct vfsconf *vfsp;
+{
+
+#ifdef DEBUG
+ printf("nullfs_init\n"); /* printed during system boot */
+#endif
+ null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
+ return (0);
+}
+
+/*
+ * Return a VREF'ed alias for lower vnode if already exists, else 0.
+ */
+static struct vnode *
+null_node_find(mp, lowervp)
+ struct mount *mp;
+ struct vnode *lowervp;
+{
+ struct proc *p = curproc; /* XXX */
+ struct null_node_hashhead *hd;
+ struct null_node *a;
+ struct vnode *vp;
+
+ /*
+ * Find hash base, and then search the (two-way) linked
+ * list looking for a null_node structure which is referencing
+ * the lower vnode. If found, the increment the null_node
+ * reference count (but NOT the lower vnode's VREF counter).
+ */
+ hd = NULL_NHASH(lowervp);
+loop:
+ for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
+ if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
+ vp = NULLTOV(a);
+ /*
+ * We need vget for the VXLOCK
+ * stuff, but we don't want to lock
+ * the lower node.
+ */
+ if (vget(vp, 0, p)) {
+ printf ("null_node_find: vget failed.\n");
+ goto loop;
+ };
+ return (vp);
+ }
+ }
+
+ return NULLVP;
+}
+
+
+/*
+ * Make a new null_node node.
+ * Vp is the alias vnode, lofsvp is the lower vnode.
+ * Maintain a reference to (lowervp).
+ */
+static int
+null_node_alloc(mp, lowervp, vpp)
+ struct mount *mp;
+ struct vnode *lowervp;
+ struct vnode **vpp;
+{
+ struct null_node_hashhead *hd;
+ struct null_node *xp;
+ struct vnode *othervp, *vp;
+ int error;
+
+ /*
+ * Do the MALLOC before the getnewvnode since doing so afterward
+ * might cause a bogus v_data pointer to get dereferenced
+ * elsewhere if MALLOC should block.
+ */
+ MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
+
+ error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp);
+ if (error) {
+ FREE(xp, M_TEMP);
+ return (error);
+ }
+ vp = *vpp;
+
+ vp->v_type = lowervp->v_type;
+ xp->null_vnode = vp;
+ vp->v_data = xp;
+ xp->null_lowervp = lowervp;
+ /*
+ * Before we insert our new node onto the hash chains,
+ * check to see if someone else has beaten us to it.
+ * (We could have slept in MALLOC.)
+ */
+ othervp = null_node_find(mp, lowervp);
+ if (othervp) {
+ FREE(xp, M_TEMP);
+ vp->v_type = VBAD; /* node is discarded */
+ vp->v_usecount = 0; /* XXX */
+ *vpp = othervp;
+ return 0;
+ };
+ VREF(lowervp); /* Extra VREF will be vrele'd in null_node_create */
+ hd = NULL_NHASH(lowervp);
+ LIST_INSERT_HEAD(hd, xp, null_hash);
+ return 0;
+}
+
+
+/*
+ * Try to find an existing null_node vnode refering
+ * to it, otherwise make a new null_node vnode which
+ * contains a reference to the lower vnode.
+ */
+int
+null_node_create(mp, lowervp, newvpp)
+ struct mount *mp;
+ struct vnode *lowervp;
+ struct vnode **newvpp;
+{
+ struct vnode *aliasvp;
+
+ aliasvp = null_node_find(mp, lowervp);
+ if (aliasvp) {
+ /*
+ * null_node_find has taken another reference
+ * to the alias vnode.
+ */
+#ifdef DEBUG
+ vprint("null_node_create: exists", aliasvp);
+#endif
+ /* VREF(aliasvp); --- done in null_node_find */
+ } else {
+ int error;
+
+ /*
+ * Get new vnode.
+ */
+#ifdef DEBUG
+ printf("null_node_create: create new alias vnode\n");
+#endif
+
+ /*
+ * Make new vnode reference the null_node.
+ */
+ error = null_node_alloc(mp, lowervp, &aliasvp);
+ if (error)
+ return error;
+
+ /*
+ * aliasvp is already VREF'd by getnewvnode()
+ */
+ }
+
+ vrele(lowervp);
+
+#ifdef DIAGNOSTIC
+ if (lowervp->v_usecount < 1) {
+ /* Should never happen... */
+ vprint ("null_node_create: alias ", aliasvp);
+ vprint ("null_node_create: lower ", lowervp);
+ panic ("null_node_create: lower has 0 usecount.");
+ };
+#endif
+
+#ifdef DEBUG
+ vprint("null_node_create: alias", aliasvp);
+ vprint("null_node_create: lower", lowervp);
+#endif
+
+ *newvpp = aliasvp;
+ return (0);
+}
+
+#ifdef DIAGNOSTIC
+#include "opt_ddb.h"
+
+#ifdef DDB
+#define null_checkvp_barrier 1
+#else
+#define null_checkvp_barrier 0
+#endif
+
+struct vnode *
+null_checkvp(vp, fil, lno)
+ struct vnode *vp;
+ char *fil;
+ int lno;
+{
+ struct null_node *a = VTONULL(vp);
+#ifdef notyet
+ /*
+ * Can't do this check because vop_reclaim runs
+ * with a funny vop vector.
+ */
+ if (vp->v_op != null_vnodeop_p) {
+ printf ("null_checkvp: on non-null-node\n");
+ while (null_checkvp_barrier) /*WAIT*/ ;
+ panic("null_checkvp");
+ };
+#endif
+ if (a->null_lowervp == NULLVP) {
+ /* Should never happen */
+ int i; u_long *p;
+ printf("vp = %p, ZERO ptr\n", (void *)vp);
+ for (p = (u_long *) a, i = 0; i < 8; i++)
+ printf(" %lx", p[i]);
+ printf("\n");
+ /* wait for debugger */
+ while (null_checkvp_barrier) /*WAIT*/ ;
+ panic("null_checkvp");
+ }
+ if (a->null_lowervp->v_usecount < 1) {
+ int i; u_long *p;
+ printf("vp = %p, unref'ed lowervp\n", (void *)vp);
+ for (p = (u_long *) a, i = 0; i < 8; i++)
+ printf(" %lx", p[i]);
+ printf("\n");
+ /* wait for debugger */
+ while (null_checkvp_barrier) /*WAIT*/ ;
+ panic ("null with unref'ed lowervp");
+ };
+#ifdef notyet
+ printf("null %x/%d -> %x/%d [%s, %d]\n",
+ NULLTOV(a), NULLTOV(a)->v_usecount,
+ a->null_lowervp, a->null_lowervp->v_usecount,
+ fil, lno);
+#endif
+ return a->null_lowervp;
+}
+#endif
diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c
new file mode 100644
index 0000000..cbeadc3
--- /dev/null
+++ b/sys/fs/nullfs/null_vfsops.c
@@ -0,0 +1,450 @@
+/*
+ * 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 8.2 (Berkeley) 1/21/94
+ *
+ * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
+ * $FreeBSD$
+ */
+
+/*
+ * Null Layer
+ * (See null_vnops.c for a description of what this does.)
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/proc.h>
+#include <sys/malloc.h>
+#include <sys/vnode.h>
+#include <sys/mount.h>
+#include <sys/namei.h>
+#include <miscfs/nullfs/null.h>
+#include <vm/vm_zone.h>
+
+static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
+
+static int nullfs_fhtovp __P((struct mount *mp, struct fid *fidp,
+ struct vnode **vpp));
+static int nullfs_checkexp __P((struct mount *mp, struct sockaddr *nam,
+ int *extflagsp, struct ucred **credanonp));
+static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data,
+ struct nameidata *ndp, struct proc *p));
+static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid,
+ caddr_t arg, struct proc *p));
+static int nullfs_root __P((struct mount *mp, struct vnode **vpp));
+static int nullfs_start __P((struct mount *mp, int flags, struct proc *p));
+static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp,
+ struct proc *p));
+static int nullfs_sync __P((struct mount *mp, int waitfor,
+ struct ucred *cred, struct proc *p));
+static int nullfs_unmount __P((struct mount *mp, int mntflags,
+ struct proc *p));
+static int nullfs_vget __P((struct mount *mp, ino_t ino,
+ struct vnode **vpp));
+static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp));
+
+/*
+ * Mount null layer
+ */
+static 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;
+ int isvnunlocked = 0;
+
+#ifdef DEBUG
+ printf("nullfs_mount(mp = %p)\n", (void *)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
+ */
+ error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
+ if (error)
+ return (error);
+
+ /*
+ * Unlock lower node to avoid deadlock.
+ * (XXX) VOP_ISLOCKED is needed?
+ */
+ if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) &&
+ VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
+ VOP_UNLOCK(mp->mnt_vnodecovered, 0, p);
+ isvnunlocked = 1;
+ }
+ /*
+ * Find lower node
+ */
+ NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
+ UIO_USERSPACE, args.target, p);
+ error = namei(ndp);
+ /*
+ * Re-lock vnode.
+ */
+ if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
+ vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p);
+
+ if (error)
+ return (error);
+ NDFREE(ndp, NDF_ONLY_PNBUF);
+
+ /*
+ * Sanity check on lower vnode
+ */
+ lowerrootvp = ndp->ni_vp;
+
+ vrele(ndp->ni_dvp);
+ ndp->ni_dvp = NULLVP;
+
+ /*
+ * Check multi null mount to avoid `lock against myself' panic.
+ */
+ if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
+#ifdef DEBUG
+ printf("nullfs_mount: multi null mount?\n");
+#endif
+ return (EDEADLK);
+ }
+
+ xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
+ M_NULLFSMNT, 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_NULLFSMNT); /* 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);
+ (void)nullfs_statfs(mp, &mp->mnt_stat, p);
+#ifdef DEBUG
+ 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.
+ */
+static 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
+ */
+static 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 DEBUG
+ printf("nullfs_unmount(mp = %p)\n", (void *)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);
+ error = vflush(mp, nullm_rootvp, flags);
+ if (error)
+ return (error);
+
+#ifdef DEBUG
+ 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_NULLFSMNT); /* XXX */
+ mp->mnt_data = 0;
+ return 0;
+}
+
+static int
+nullfs_root(mp, vpp)
+ struct mount *mp;
+ struct vnode **vpp;
+{
+ struct proc *p = curproc; /* XXX */
+ struct vnode *vp;
+
+#ifdef DEBUG
+ printf("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
+ (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
+ (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
+#endif
+
+ /*
+ * Return locked reference to root.
+ */
+ vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
+ VREF(vp);
+ if (VOP_ISLOCKED(vp, NULL)) {
+ /*
+ * XXX
+ * Should we check type of node?
+ */
+#ifdef DEBUG
+ printf("nullfs_root: multi null mount?\n");
+#endif
+ vrele(vp);
+ return (EDEADLK);
+ } else
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
+ *vpp = vp;
+ return 0;
+}
+
+static 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);
+}
+
+static int
+nullfs_statfs(mp, sbp, p)
+ struct mount *mp;
+ struct statfs *sbp;
+ struct proc *p;
+{
+ int error;
+ struct statfs mstat;
+
+#ifdef DEBUG
+ printf("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
+ (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
+ (void *)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);
+}
+
+static 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);
+}
+
+static int
+nullfs_vget(mp, ino, vpp)
+ struct mount *mp;
+ ino_t ino;
+ struct vnode **vpp;
+{
+
+ return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
+}
+
+static int
+nullfs_fhtovp(mp, fidp, vpp)
+ struct mount *mp;
+ struct fid *fidp;
+ struct vnode **vpp;
+{
+
+ return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
+}
+
+static int
+nullfs_checkexp(mp, nam, extflagsp, credanonp)
+ struct mount *mp;
+ struct sockaddr *nam;
+ int *extflagsp;
+ struct ucred **credanonp;
+{
+
+ return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
+ extflagsp, credanonp);
+}
+
+static int
+nullfs_vptofh(vp, fhp)
+ struct vnode *vp;
+ struct fid *fhp;
+{
+ return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
+}
+
+static int
+nullfs_extattrctl(mp, cmd, attrname, arg, p)
+ struct mount *mp;
+ int cmd;
+ char *attrname;
+ caddr_t arg;
+ struct proc *p;
+{
+ return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
+ arg, p);
+}
+
+
+static struct vfsops null_vfsops = {
+ nullfs_mount,
+ nullfs_start,
+ nullfs_unmount,
+ nullfs_root,
+ nullfs_quotactl,
+ nullfs_statfs,
+ nullfs_sync,
+ nullfs_vget,
+ nullfs_fhtovp,
+ nullfs_checkexp,
+ nullfs_vptofh,
+ nullfs_init,
+ vfs_stduninit,
+ nullfs_extattrctl,
+};
+
+VFS_SET(null_vfsops, null, VFCF_LOOPBACK);
diff --git a/sys/fs/nullfs/null_vnops.c b/sys/fs/nullfs/null_vnops.c
new file mode 100644
index 0000000..9600f3c
--- /dev/null
+++ b/sys/fs/nullfs/null_vnops.c
@@ -0,0 +1,610 @@
+/*
+ * Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * John Heidemann of the UCLA Ficus project.
+ *
+ * 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_vnops.c 8.6 (Berkeley) 5/27/95
+ *
+ * Ancestors:
+ * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92
+ * $FreeBSD$
+ * ...and...
+ * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Null Layer
+ *
+ * (See mount_null(8) for more information.)
+ *
+ * The null layer duplicates a portion of the file system
+ * name space under a new name. In this respect, it is
+ * similar to the loopback file system. It differs from
+ * the loopback fs in two respects: it is implemented using
+ * a stackable layers techniques, and its "null-node"s stack above
+ * all lower-layer vnodes, not just over directory vnodes.
+ *
+ * The null layer has two purposes. First, it serves as a demonstration
+ * of layering by proving a layer which does nothing. (It actually
+ * does everything the loopback file system does, which is slightly
+ * more than nothing.) Second, the null layer can serve as a prototype
+ * layer. Since it provides all necessary layer framework,
+ * new file system layers can be created very easily be starting
+ * with a null layer.
+ *
+ * The remainder of this man page examines the null layer as a basis
+ * for constructing new layers.
+ *
+ *
+ * INSTANTIATING NEW NULL LAYERS
+ *
+ * New null layers are created with mount_null(8).
+ * Mount_null(8) takes two arguments, the pathname
+ * of the lower vfs (target-pn) and the pathname where the null
+ * layer will appear in the namespace (alias-pn). After
+ * the null layer is put into place, the contents
+ * of target-pn subtree will be aliased under alias-pn.
+ *
+ *
+ * OPERATION OF A NULL LAYER
+ *
+ * The null layer is the minimum file system layer,
+ * simply bypassing all possible operations to the lower layer
+ * for processing there. The majority of its activity centers
+ * on the bypass routine, through which nearly all vnode operations
+ * pass.
+ *
+ * The bypass routine accepts arbitrary vnode operations for
+ * handling by the lower layer. It begins by examing vnode
+ * operation arguments and replacing any null-nodes by their
+ * lower-layer equivlants. It then invokes the operation
+ * on the lower layer. Finally, it replaces the null-nodes
+ * in the arguments and, if a vnode is return by the operation,
+ * stacks a null-node on top of the returned vnode.
+ *
+ * Although bypass handles most operations, vop_getattr, vop_lock,
+ * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not
+ * bypassed. Vop_getattr must change the fsid being returned.
+ * Vop_lock and vop_unlock must handle any locking for the
+ * current vnode as well as pass the lock request down.
+ * Vop_inactive and vop_reclaim are not bypassed so that
+ * they can handle freeing null-layer specific data. Vop_print
+ * is not bypassed to avoid excessive debugging information.
+ * Also, certain vnode operations change the locking state within
+ * the operation (create, mknod, remove, link, rename, mkdir, rmdir,
+ * and symlink). Ideally these operations should not change the
+ * lock state, but should be changed to let the caller of the
+ * function unlock them. Otherwise all intermediate vnode layers
+ * (such as union, umapfs, etc) must catch these functions to do
+ * the necessary locking at their layer.
+ *
+ *
+ * INSTANTIATING VNODE STACKS
+ *
+ * Mounting associates the null layer with a lower layer,
+ * effect stacking two VFSes. Vnode stacks are instead
+ * created on demand as files are accessed.
+ *
+ * The initial mount creates a single vnode stack for the
+ * root of the new null layer. All other vnode stacks
+ * are created as a result of vnode operations on
+ * this or other null vnode stacks.
+ *
+ * New vnode stacks come into existance as a result of
+ * an operation which returns a vnode.
+ * The bypass routine stacks a null-node above the new
+ * vnode before returning it to the caller.
+ *
+ * For example, imagine mounting a null layer with
+ * "mount_null /usr/include /dev/layer/null".
+ * Changing directory to /dev/layer/null will assign
+ * the root null-node (which was created when the null layer was mounted).
+ * Now consider opening "sys". A vop_lookup would be
+ * done on the root null-node. This operation would bypass through
+ * to the lower layer which would return a vnode representing
+ * the UFS "sys". Null_bypass then builds a null-node
+ * aliasing the UFS "sys" and returns this to the caller.
+ * Later operations on the null-node "sys" will repeat this
+ * process when constructing other vnode stacks.
+ *
+ *
+ * CREATING OTHER FILE SYSTEM LAYERS
+ *
+ * One of the easiest ways to construct new file system layers is to make
+ * a copy of the null layer, rename all files and variables, and
+ * then begin modifing the copy. Sed can be used to easily rename
+ * all variables.
+ *
+ * The umap layer is an example of a layer descended from the
+ * null layer.
+ *
+ *
+ * INVOKING OPERATIONS ON LOWER LAYERS
+ *
+ * There are two techniques to invoke operations on a lower layer
+ * when the operation cannot be completely bypassed. Each method
+ * is appropriate in different situations. In both cases,
+ * it is the responsibility of the aliasing layer to make
+ * the operation arguments "correct" for the lower layer
+ * by mapping an vnode arguments to the lower layer.
+ *
+ * The first approach is to call the aliasing layer's bypass routine.
+ * This method is most suitable when you wish to invoke the operation
+ * currently being handled on the lower layer. It has the advantage
+ * that the bypass routine already must do argument mapping.
+ * An example of this is null_getattrs in the null layer.
+ *
+ * A second approach is to directly invoke vnode operations on
+ * the lower layer with the VOP_OPERATIONNAME interface.
+ * The advantage of this method is that it is easy to invoke
+ * arbitrary operations on the lower layer. The disadvantage
+ * is that vnode arguments must be manualy mapped.
+ *
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+#include <sys/vnode.h>
+#include <sys/mount.h>
+#include <sys/namei.h>
+#include <sys/malloc.h>
+#include <sys/buf.h>
+#include <miscfs/nullfs/null.h>
+
+static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */
+SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW,
+ &null_bug_bypass, 0, "");
+
+static int null_access __P((struct vop_access_args *ap));
+static int null_getattr __P((struct vop_getattr_args *ap));
+static int null_inactive __P((struct vop_inactive_args *ap));
+static int null_lock __P((struct vop_lock_args *ap));
+static int null_lookup __P((struct vop_lookup_args *ap));
+static int null_print __P((struct vop_print_args *ap));
+static int null_reclaim __P((struct vop_reclaim_args *ap));
+static int null_setattr __P((struct vop_setattr_args *ap));
+static int null_unlock __P((struct vop_unlock_args *ap));
+
+/*
+ * This is the 10-Apr-92 bypass routine.
+ * This version has been optimized for speed, throwing away some
+ * safety checks. It should still always work, but it's not as
+ * robust to programmer errors.
+ *
+ * In general, we map all vnodes going down and unmap them on the way back.
+ * As an exception to this, vnodes can be marked "unmapped" by setting
+ * the Nth bit in operation's vdesc_flags.
+ *
+ * Also, some BSD vnode operations have the side effect of vrele'ing
+ * their arguments. With stacking, the reference counts are held
+ * by the upper node, not the lower one, so we must handle these
+ * side-effects here. This is not of concern in Sun-derived systems
+ * since there are no such side-effects.
+ *
+ * This makes the following assumptions:
+ * - only one returned vpp
+ * - no INOUT vpp's (Sun's vop_open has one of these)
+ * - the vnode operation vector of the first vnode should be used
+ * to determine what implementation of the op should be invoked
+ * - all mapped vnodes are of our vnode-type (NEEDSWORK:
+ * problems on rmdir'ing mount points and renaming?)
+ */
+int
+null_bypass(ap)
+ struct vop_generic_args /* {
+ struct vnodeop_desc *a_desc;
+ <other random data follows, presumably>
+ } */ *ap;
+{
+ register struct vnode **this_vp_p;
+ int error;
+ struct vnode *old_vps[VDESC_MAX_VPS];
+ struct vnode **vps_p[VDESC_MAX_VPS];
+ struct vnode ***vppp;
+ struct vnodeop_desc *descp = ap->a_desc;
+ int reles, i;
+
+ if (null_bug_bypass)
+ printf ("null_bypass: %s\n", descp->vdesc_name);
+
+#ifdef DIAGNOSTIC
+ /*
+ * We require at least one vp.
+ */
+ if (descp->vdesc_vp_offsets == NULL ||
+ descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
+ panic ("null_bypass: no vp's in map");
+#endif
+
+ /*
+ * Map the vnodes going in.
+ * Later, we'll invoke the operation based on
+ * the first mapped vnode's operation vector.
+ */
+ reles = descp->vdesc_flags;
+ for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
+ if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
+ break; /* bail out at end of list */
+ vps_p[i] = this_vp_p =
+ VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
+ /*
+ * We're not guaranteed that any but the first vnode
+ * are of our type. Check for and don't map any
+ * that aren't. (We must always map first vp or vclean fails.)
+ */
+ if (i && (*this_vp_p == NULLVP ||
+ (*this_vp_p)->v_op != null_vnodeop_p)) {
+ old_vps[i] = NULLVP;
+ } else {
+ old_vps[i] = *this_vp_p;
+ *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p);
+ /*
+ * XXX - Several operations have the side effect
+ * of vrele'ing their vp's. We must account for
+ * that. (This should go away in the future.)
+ */
+ if (reles & 1)
+ VREF(*this_vp_p);
+ }
+
+ }
+
+ /*
+ * Call the operation on the lower layer
+ * with the modified argument structure.
+ */
+ error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap);
+
+ /*
+ * Maintain the illusion of call-by-value
+ * by restoring vnodes in the argument structure
+ * to their original value.
+ */
+ reles = descp->vdesc_flags;
+ for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
+ if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
+ break; /* bail out at end of list */
+ if (old_vps[i]) {
+ *(vps_p[i]) = old_vps[i];
+ if (reles & 1)
+ vrele(*(vps_p[i]));
+ }
+ }
+
+ /*
+ * Map the possible out-going vpp
+ * (Assumes that the lower layer always returns
+ * a VREF'ed vpp unless it gets an error.)
+ */
+ if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
+ !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
+ !error) {
+ /*
+ * XXX - even though some ops have vpp returned vp's,
+ * several ops actually vrele this before returning.
+ * We must avoid these ops.
+ * (This should go away when these ops are regularized.)
+ */
+ if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
+ goto out;
+ vppp = VOPARG_OFFSETTO(struct vnode***,
+ descp->vdesc_vpp_offset,ap);
+ if (*vppp)
+ error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
+ }
+
+ out:
+ return (error);
+}
+
+/*
+ * We have to carry on the locking protocol on the null layer vnodes
+ * as we progress through the tree. We also have to enforce read-only
+ * if this layer is mounted read-only.
+ */
+static int
+null_lookup(ap)
+ struct vop_lookup_args /* {
+ struct vnode * a_dvp;
+ struct vnode ** a_vpp;
+ struct componentname * a_cnp;
+ } */ *ap;
+{
+ struct componentname *cnp = ap->a_cnp;
+ struct proc *p = cnp->cn_proc;
+ int flags = cnp->cn_flags;
+ struct vop_lock_args lockargs;
+ struct vop_unlock_args unlockargs;
+ struct vnode *dvp, *vp;
+ int error;
+
+ if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
+ (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
+ return (EROFS);
+ error = null_bypass((struct vop_generic_args *)ap);
+ if (error == EJUSTRETURN && (flags & ISLASTCN) &&
+ (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
+ (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
+ error = EROFS;
+ /*
+ * We must do the same locking and unlocking at this layer as
+ * is done in the layers below us. We could figure this out
+ * based on the error return and the LASTCN, LOCKPARENT, and
+ * LOCKLEAF flags. However, it is more expidient to just find
+ * out the state of the lower level vnodes and set ours to the
+ * same state.
+ */
+ dvp = ap->a_dvp;
+ vp = *ap->a_vpp;
+ if (dvp == vp)
+ return (error);
+ if (!VOP_ISLOCKED(dvp, NULL)) {
+ unlockargs.a_vp = dvp;
+ unlockargs.a_flags = 0;
+ unlockargs.a_p = p;
+ vop_nounlock(&unlockargs);
+ }
+ if (vp != NULLVP && VOP_ISLOCKED(vp, NULL)) {
+ lockargs.a_vp = vp;
+ lockargs.a_flags = LK_SHARED;
+ lockargs.a_p = p;
+ vop_nolock(&lockargs);
+ }
+ return (error);
+}
+
+/*
+ * Setattr call. Disallow write attempts if the layer is mounted read-only.
+ */
+int
+null_setattr(ap)
+ struct vop_setattr_args /* {
+ struct vnodeop_desc *a_desc;
+ struct vnode *a_vp;
+ struct vattr *a_vap;
+ struct ucred *a_cred;
+ struct proc *a_p;
+ } */ *ap;
+{
+ struct vnode *vp = ap->a_vp;
+ struct vattr *vap = ap->a_vap;
+
+ if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
+ vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
+ vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
+ (vp->v_mount->mnt_flag & MNT_RDONLY))
+ return (EROFS);
+ if (vap->va_size != VNOVAL) {
+ switch (vp->v_type) {
+ case VDIR:
+ return (EISDIR);
+ case VCHR:
+ case VBLK:
+ case VSOCK:
+ case VFIFO:
+ if (vap->va_flags != VNOVAL)
+ return (EOPNOTSUPP);
+ return (0);
+ case VREG:
+ case VLNK:
+ default:
+ /*
+ * Disallow write attempts if the filesystem is
+ * mounted read-only.
+ */
+ if (vp->v_mount->mnt_flag & MNT_RDONLY)
+ return (EROFS);
+ }
+ }
+ return (null_bypass((struct vop_generic_args *)ap));
+}
+
+/*
+ * We handle getattr only to change the fsid.
+ */
+static int
+null_getattr(ap)
+ struct vop_getattr_args /* {
+ struct vnode *a_vp;
+ struct vattr *a_vap;
+ struct ucred *a_cred;
+ struct proc *a_p;
+ } */ *ap;
+{
+ int error;
+
+ if ((error = null_bypass((struct vop_generic_args *)ap)) != 0)
+ return (error);
+ return (0);
+}
+
+static int
+null_access(ap)
+ struct vop_access_args /* {
+ struct vnode *a_vp;
+ int a_mode;
+ struct ucred *a_cred;
+ struct proc *a_p;
+ } */ *ap;
+{
+ struct vnode *vp = ap->a_vp;
+ mode_t mode = ap->a_mode;
+
+ /*
+ * Disallow write attempts on read-only layers;
+ * unless the file is a socket, fifo, or a block or
+ * character device resident on the file system.
+ */
+ if (mode & VWRITE) {
+ switch (vp->v_type) {
+ case VDIR:
+ case VLNK:
+ case VREG:
+ if (vp->v_mount->mnt_flag & MNT_RDONLY)
+ return (EROFS);
+ break;
+ default:
+ break;
+ }
+ }
+ return (null_bypass((struct vop_generic_args *)ap));
+}
+
+/*
+ * We need to process our own vnode lock and then clear the
+ * interlock flag as it applies only to our vnode, not the
+ * vnodes below us on the stack.
+ */
+static int
+null_lock(ap)
+ struct vop_lock_args /* {
+ struct vnode *a_vp;
+ int a_flags;
+ struct proc *a_p;
+ } */ *ap;
+{
+
+ vop_nolock(ap);
+ if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN)
+ return (0);
+ ap->a_flags &= ~LK_INTERLOCK;
+ return (null_bypass((struct vop_generic_args *)ap));
+}
+
+/*
+ * We need to process our own vnode unlock and then clear the
+ * interlock flag as it applies only to our vnode, not the
+ * vnodes below us on the stack.
+ */
+static int
+null_unlock(ap)
+ struct vop_unlock_args /* {
+ struct vnode *a_vp;
+ int a_flags;
+ struct proc *a_p;
+ } */ *ap;
+{
+ vop_nounlock(ap);
+ ap->a_flags &= ~LK_INTERLOCK;
+ return (null_bypass((struct vop_generic_args *)ap));
+}
+
+static int
+null_inactive(ap)
+ struct vop_inactive_args /* {
+ struct vnode *a_vp;
+ struct proc *a_p;
+ } */ *ap;
+{
+ struct vnode *vp = ap->a_vp;
+ struct null_node *xp = VTONULL(vp);
+ struct vnode *lowervp = xp->null_lowervp;
+ /*
+ * Do nothing (and _don't_ bypass).
+ * Wait to vrele lowervp until reclaim,
+ * so that until then our null_node is in the
+ * cache and reusable.
+ * We still have to tell the lower layer the vnode
+ * is now inactive though.
+ *
+ * NEEDSWORK: Someday, consider inactive'ing
+ * the lowervp and then trying to reactivate it
+ * with capabilities (v_id)
+ * like they do in the name lookup cache code.
+ * That's too much work for now.
+ */
+ VOP_INACTIVE(lowervp, ap->a_p);
+ VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
+ return (0);
+}
+
+static int
+null_reclaim(ap)
+ struct vop_reclaim_args /* {
+ struct vnode *a_vp;
+ struct proc *a_p;
+ } */ *ap;
+{
+ struct vnode *vp = ap->a_vp;
+ struct null_node *xp = VTONULL(vp);
+ struct vnode *lowervp = xp->null_lowervp;
+
+ /*
+ * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p,
+ * so we can't call VOPs on ourself.
+ */
+ /* After this assignment, this node will not be re-used. */
+ xp->null_lowervp = NULLVP;
+ LIST_REMOVE(xp, null_hash);
+ FREE(vp->v_data, M_TEMP);
+ vp->v_data = NULL;
+ vrele (lowervp);
+ return (0);
+}
+
+static int
+null_print(ap)
+ struct vop_print_args /* {
+ struct vnode *a_vp;
+ } */ *ap;
+{
+ register struct vnode *vp = ap->a_vp;
+ printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp));
+ return (0);
+}
+
+/*
+ * Global vfs data structures
+ */
+vop_t **null_vnodeop_p;
+static struct vnodeopv_entry_desc null_vnodeop_entries[] = {
+ { &vop_default_desc, (vop_t *) null_bypass },
+ { &vop_access_desc, (vop_t *) null_access },
+ { &vop_getattr_desc, (vop_t *) null_getattr },
+ { &vop_inactive_desc, (vop_t *) null_inactive },
+ { &vop_lock_desc, (vop_t *) null_lock },
+ { &vop_lookup_desc, (vop_t *) null_lookup },
+ { &vop_print_desc, (vop_t *) null_print },
+ { &vop_reclaim_desc, (vop_t *) null_reclaim },
+ { &vop_setattr_desc, (vop_t *) null_setattr },
+ { &vop_unlock_desc, (vop_t *) null_unlock },
+ { NULL, NULL }
+};
+static struct vnodeopv_desc null_vnodeop_opv_desc =
+ { &null_vnodeop_p, null_vnodeop_entries };
+
+VNODEOP_SET(null_vnodeop_opv_desc);
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