IABSD.fr/src/sys/nfs/nfs_node.c

Branch : - branch - master - tag -

• Show log

  Commit

• Author : visa
  Date : 2022-06-27 13:39:58
  Hash : 4620961b
  Message : Fix lock order reversal in nfs_inactive() Make the silly file removal happen after the vnode has been unlocked. This avoids a file-directory reversal in the vnode locking order. OK jca@

• sys/nfs/nfs_node.c

• /*	$OpenBSD: nfs_node.c,v 1.75 2022/06/27 13:39:58 visa Exp $	*/
  /*	$NetBSD: nfs_node.c,v 1.16 1996/02/18 11:53:42 fvdl Exp $	*/
  
  /*
   * Copyright (c) 1989, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software contributed to Berkeley by
   * Rick Macklem at The University of Guelph.
   *
   * 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. 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.
   *
   *	@(#)nfs_node.c	8.6 (Berkeley) 5/22/95
   */
  
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/timeout.h>
  #include <sys/mount.h>
  #include <sys/namei.h>
  #include <sys/vnode.h>
  #include <sys/lock.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/pool.h>
  #include <sys/rwlock.h>
  #include <sys/queue.h>
  
  #include <nfs/rpcv2.h>
  #include <nfs/nfsproto.h>
  #include <nfs/nfsnode.h>
  #include <nfs/nfsmount.h>
  #include <nfs/nfs_var.h>
  
  struct pool nfs_node_pool;
  extern int prtactive;
  
  /* XXX */
  extern const struct vops nfs_vops;
  
  /* filehandle to node lookup. */
  static __inline int
  nfsnode_cmp(const struct nfsnode *a, const struct nfsnode *b)
  {
  	if (a->n_fhsize != b->n_fhsize)
  		return (a->n_fhsize - b->n_fhsize);
  	return (memcmp(a->n_fhp, b->n_fhp, a->n_fhsize));
  }
  
  RBT_PROTOTYPE(nfs_nodetree, nfsnode, n_entry, nfsnode_cmp);
  RBT_GENERATE(nfs_nodetree, nfsnode, n_entry, nfsnode_cmp);
  
  void
  nfs_ninit(struct nfsmount *nmp)
  {
  	RBT_INIT(nfs_nodetree, &nmp->nm_ntree);
  }
  
  /*
   * Look up a vnode/nfsnode by file handle and store the pointer in *npp.
   * Callers must check for mount points!!
   * An error number is returned.
   */
  int
  nfs_nget(struct mount *mnt, nfsfh_t *fh, int fhsize, struct nfsnode **npp)
  {
  	struct nfsmount		*nmp;
  	struct nfsnode		*np, find, *np2;
  	struct vnode		*vp, *nvp;
  	int			 error;
  
  	nmp = VFSTONFS(mnt);
  
  loop:
  	find.n_fhp = fh;
  	find.n_fhsize = fhsize;
  	np = RBT_FIND(nfs_nodetree, &nmp->nm_ntree, &find);
  	if (np != NULL) {
  		vp = NFSTOV(np);
  		error = vget(vp, LK_EXCLUSIVE);
  		if (error)
  			goto loop;
  		*npp = np;
  		return (0);
  	}
  
  	/*
  	 * getnewvnode() could recycle a vnode, potentially formerly
  	 * owned by NFS. This will cause a VOP_RECLAIM() to happen,
  	 * which will cause recursive locking, so we unlock before
  	 * calling getnewvnode() lock again afterwards, but must check
  	 * to see if this nfsnode has been added while we did not hold
  	 * the lock.
  	 */
  	error = getnewvnode(VT_NFS, mnt, &nfs_vops, &nvp);
  	/* note that we don't have this vnode set up completely yet */
  	if (error) {
  		*npp = NULL;
  		return (error);
  	}
  	nvp->v_flag |= VLARVAL;
  	np = pool_get(&nfs_node_pool, PR_WAITOK | PR_ZERO);
  	/*
  	 * getnewvnode() and pool_get() can sleep, check for race.
  	 */
  	if (RBT_FIND(nfs_nodetree, &nmp->nm_ntree, &find) != NULL) {
  		pool_put(&nfs_node_pool, np);
  		vgone(nvp);
  		goto loop;
  	}
  
  	vp = nvp;
  #ifdef VFSLCKDEBUG
  	vp->v_flag |= VLOCKSWORK;
  #endif
  	rrw_init_flags(&np->n_lock, "nfsnode", RWL_DUPOK | RWL_IS_VNODE);
  	vp->v_data = np;
  	/* we now have an nfsnode on this vnode */
  	vp->v_flag &= ~VLARVAL;
  	np->n_vnode = vp;
  	rw_init(&np->n_commitlock, "nfs_commitlk");
  	np->n_fhp = &np->n_fh;
  	bcopy(fh, np->n_fhp, fhsize);
  	np->n_fhsize = fhsize;
  	/* lock the nfsnode, then put it on the rbtree */
  	VOP_LOCK(vp, LK_EXCLUSIVE);
  	np2 = RBT_INSERT(nfs_nodetree, &nmp->nm_ntree, np);
  	KASSERT(np2 == NULL);
  	np->n_accstamp = -1;
  	*npp = np;
  
  	return (0);
  }
  
  int
  nfs_inactive(void *v)
  {
  	struct vop_inactive_args	*ap = v;
  	struct nfsnode			*np;
  	struct sillyrename		*sp;
  
  #ifdef DIAGNOSTIC
  	if (prtactive && ap->a_vp->v_usecount != 0)
  		vprint("nfs_inactive: pushing active", ap->a_vp);
  #endif
  	if (ap->a_vp->v_flag & VLARVAL)
  		/*
  		 * vnode was incompletely set up, just return
  		 * as we are throwing it away.
  		 */
  		return(0);
  #ifdef DIAGNOSTIC
  	if (ap->a_vp->v_data == NULL)
  		panic("NULL v_data (no nfsnode set up?) in vnode %p",
  		    ap->a_vp);
  #endif
  	np = VTONFS(ap->a_vp);
  	if (ap->a_vp->v_type != VDIR) {
  		sp = np->n_sillyrename;
  		np->n_sillyrename = NULL;
  	} else
  		sp = NULL;
  	if (sp != NULL)
  		nfs_vinvalbuf(ap->a_vp, 0, sp->s_cred, curproc);
  	np->n_flag &= (NMODIFIED | NFLUSHINPROG | NFLUSHWANT);
  
  	VOP_UNLOCK(ap->a_vp);
  
  	if (sp != NULL) {
  		/*
  		 * Remove the silly file that was rename'd earlier
  		 */
  		vn_lock(sp->s_dvp, LK_EXCLUSIVE | LK_RETRY);
  		nfs_removeit(sp);
  		crfree(sp->s_cred);
  		vput(sp->s_dvp);
  		free(sp, M_NFSREQ, sizeof(*sp));
  	}
  
  	return (0);
  }
  
  /*
   * Reclaim an nfsnode so that it can be used for other purposes.
   */
  int
  nfs_reclaim(void *v)
  {
  	struct vop_reclaim_args	*ap = v;
  	struct vnode		*vp = ap->a_vp;
  	struct nfsmount		*nmp;
  	struct nfsnode		*np = VTONFS(vp);
  
  #ifdef DIAGNOSTIC
  	if (prtactive && vp->v_usecount != 0)
  		vprint("nfs_reclaim: pushing active", vp);
  #endif
  	if (ap->a_vp->v_flag & VLARVAL)
  		/*
  		 * vnode was incompletely set up, just return
  		 * as we are throwing it away.
  		 */
  		return(0);
  #ifdef DIAGNOSTIC
  	if (ap->a_vp->v_data == NULL)
  		panic("NULL v_data (no nfsnode set up?) in vnode %p",
  		    ap->a_vp);
  #endif
  	nmp = VFSTONFS(vp->v_mount);
  	RBT_REMOVE(nfs_nodetree, &nmp->nm_ntree, np);
  
  	if (np->n_rcred)
  		crfree(np->n_rcred);
  	if (np->n_wcred)
  		crfree(np->n_wcred);
  
  	cache_purge(vp);
  	pool_put(&nfs_node_pool, vp->v_data);
  	vp->v_data = NULL;
  
  	return (0);
  }