FreeBSD/Linux Kernel Cross Reference
sys/nfs/nfs_node.c

     /*
      * 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. 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.
     *
     *      @(#)nfs_node.c  8.6 (Berkeley) 5/22/95
     * $FreeBSD$
     */
    
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/proc.h>
    #include <sys/mount.h>
    #include <sys/namei.h>
    #include <sys/vnode.h>
    #include <sys/malloc.h>
    #include <sys/fnv_hash.h>
    
    #include <vm/vm_zone.h>
    
    #include <nfs/rpcv2.h>
    #include <nfs/nfsproto.h>
    #include <nfs/nfs.h>
    #include <nfs/nfsnode.h>
    #include <nfs/nfsmount.h>
    
    static vm_zone_t nfsnode_zone;
    static LIST_HEAD(nfsnodehashhead, nfsnode) *nfsnodehashtbl;
    static u_long nfsnodehash;
    
    #define TRUE    1
    #define FALSE   0
    
    /*
     * Initialize hash links for nfsnodes
     * and build nfsnode free list.
     */
    void
    nfs_nhinit()
    {
            nfsnode_zone = zinit("NFSNODE", sizeof(struct nfsnode), 0, 0, 1);
            nfsnodehashtbl = hashinit(desiredvnodes, M_NFSHASH, &nfsnodehash);
    }
    
    /*
     * Look up a vnode/nfsnode by file handle.
     * Callers must check for mount points!!
     * In all cases, a pointer to a
     * nfsnode structure is returned.
     */
    static int nfs_node_hash_lock;
    
    int
    nfs_nget(mntp, fhp, fhsize, npp)
            struct mount *mntp;
            register nfsfh_t *fhp;
            int fhsize;
            struct nfsnode **npp;
    {
            struct proc *p = curproc;       /* XXX */
            struct nfsnode *np, *np2;
            struct nfsnodehashhead *nhpp;
            register struct vnode *vp;
            struct vnode *nvp;
            int error;
            int rsflags;
            struct nfsmount *nmp;
    
           /*
            * Calculate nfs mount point and figure out whether the rslock should
            * be interruptable or not.
            */
           nmp = VFSTONFS(mntp);
           if (nmp->nm_flag & NFSMNT_INT)
                   rsflags = PCATCH;
           else
                   rsflags = 0;
   
   retry:
           nhpp = NFSNOHASH(fnv_32_buf(fhp->fh_bytes, fhsize, FNV1_32_INIT));
   loop:
           for (np = nhpp->lh_first; np != 0; np = np->n_hash.le_next) {
                   if (mntp != NFSTOV(np)->v_mount || np->n_fhsize != fhsize ||
                       bcmp((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize))
                           continue;
                   vp = NFSTOV(np);
                   if (vget(vp, LK_EXCLUSIVE|LK_SLEEPFAIL, p))
                           goto loop;
                   *npp = np;
                   return(0);
           }
           /*
            * Obtain a lock to prevent a race condition if the getnewvnode()
            * or MALLOC() below happens to block.
            */
           if (nfs_node_hash_lock) {
                   while (nfs_node_hash_lock) {
                           nfs_node_hash_lock = -1;
                           tsleep(&nfs_node_hash_lock, PVM, "nfsngt", 0);
                   }
                   goto loop;
           }
           nfs_node_hash_lock = 1;
   
           /*
            * Allocate before getnewvnode since doing so afterward
            * might cause a bogus v_data pointer to get dereferenced
            * elsewhere if zalloc should block.
            */
           np = zalloc(nfsnode_zone);
                   
           error = getnewvnode(VT_NFS, mntp, nfsv2_vnodeop_p, &nvp);
           if (error) {
                   if (nfs_node_hash_lock < 0)
                           wakeup(&nfs_node_hash_lock);
                   nfs_node_hash_lock = 0;
                   *npp = 0;
                   zfree(nfsnode_zone, np);
                   return (error);
           }
           vp = nvp;
           bzero((caddr_t)np, sizeof *np);
           vp->v_data = np;
           np->n_vnode = vp;
           /*
            * Insert the nfsnode in the hash queue for its new file handle
            */
           for (np2 = nhpp->lh_first; np2 != 0; np2 = np2->n_hash.le_next) {
                   if (mntp != NFSTOV(np2)->v_mount || np2->n_fhsize != fhsize ||
                       bcmp((caddr_t)fhp, (caddr_t)np2->n_fhp, fhsize))
                           continue;
                   vrele(vp);
                   if (nfs_node_hash_lock < 0)
                           wakeup(&nfs_node_hash_lock);
                   nfs_node_hash_lock = 0;
                   zfree(nfsnode_zone, np);
                   goto retry;
           }
           LIST_INSERT_HEAD(nhpp, np, n_hash);
           if (fhsize > NFS_SMALLFH) {
                   MALLOC(np->n_fhp, nfsfh_t *, fhsize, M_NFSBIGFH, M_WAITOK);
           } else
                   np->n_fhp = &np->n_fh;
           bcopy((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize);
           np->n_fhsize = fhsize;
           lockinit(&np->n_rslock, PVFS | rsflags, "nfrslk", 0, LK_NOPAUSE);
           lockinit(&np->n_lock, PVFS, "nfsnlk", 0, LK_NOPAUSE);
           *npp = np;
   
           if (nfs_node_hash_lock < 0)
                   wakeup(&nfs_node_hash_lock);
           nfs_node_hash_lock = 0;
   
           /*
            * Lock the new nfsnode.
            */
           vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
   
           return (0);
   }
   
   int
   nfs_inactive(ap)
           struct vop_inactive_args /* {
                   struct vnode *a_vp;
                   struct proc *a_p;
           } */ *ap;
   {
           register struct nfsnode *np;
           register struct sillyrename *sp;
           struct proc *p = curproc;       /* XXX */
   
           np = VTONFS(ap->a_vp);
           if (prtactive && ap->a_vp->v_usecount != 0)
                   vprint("nfs_inactive: pushing active", ap->a_vp);
           if (ap->a_vp->v_type != VDIR) {
                   sp = np->n_sillyrename;
                   np->n_sillyrename = (struct sillyrename *)0;
           } else
                   sp = (struct sillyrename *)0;
           if (sp) {
                   /*
                    * We need a reference to keep the vnode from being
                    * recycled by getnewvnode while we do the I/O
                    * associated with discarding the buffers unless we
                    * are being forcibly unmounted in which case we already
                    * have our own reference.
                    */
                   if (ap->a_vp->v_usecount > 0)
                           (void) nfs_vinvalbuf(ap->a_vp, 0, sp->s_cred, p, 1);
                   else if (vget(ap->a_vp, 0, p))
                           panic("nfs_inactive: lost vnode");
                   else {
                           (void) nfs_vinvalbuf(ap->a_vp, 0, sp->s_cred, p, 1);
                           vrele(ap->a_vp);
                   }
                   /*
                    * Remove the silly file that was rename'd earlier
                    */
                   nfs_removeit(sp);
                   crfree(sp->s_cred);
                   vrele(sp->s_dvp);
                   FREE((caddr_t)sp, M_NFSREQ);
           }
           np->n_flag &= (NMODIFIED | NFLUSHINPROG | NFLUSHWANT | NQNFSEVICTED |
                   NQNFSNONCACHE | NQNFSWRITE);
           VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
           return (0);
   }
   
   /*
    * Reclaim an nfsnode so that it can be used for other purposes.
    */
   int
   nfs_reclaim(ap)
           struct vop_reclaim_args /* {
                   struct vnode *a_vp;
           } */ *ap;
   {
           register struct vnode *vp = ap->a_vp;
           register struct nfsnode *np = VTONFS(vp);
           register struct nfsmount *nmp = VFSTONFS(vp->v_mount);
           register struct nfsdmap *dp, *dp2;
   
           if (prtactive && vp->v_usecount != 0)
                   vprint("nfs_reclaim: pushing active", vp);
   
           if (np->n_hash.le_prev != NULL)
                   LIST_REMOVE(np, n_hash);
   
           /*
            * For nqnfs, take it off the timer queue as required.
            */
           if ((nmp->nm_flag & NFSMNT_NQNFS) && np->n_timer.cqe_next != 0) {
                   CIRCLEQ_REMOVE(&nmp->nm_timerhead, np, n_timer);
           }
   
           /*
            * Free up any directory cookie structures and
            * large file handle structures that might be associated with
            * this nfs node.
            */
           if (vp->v_type == VDIR) {
                   dp = np->n_cookies.lh_first;
                   while (dp) {
                           dp2 = dp;
                           dp = dp->ndm_list.le_next;
                           FREE((caddr_t)dp2, M_NFSDIROFF);
                   }
           }
           if (np->n_fhsize > NFS_SMALLFH) {
                   FREE((caddr_t)np->n_fhp, M_NFSBIGFH);
           }
   
           cache_purge(vp);
           zfree(nfsnode_zone, vp->v_data);
           vp->v_data = (void *)0;
           return (0);
   }
   
   #if 0
   /*
    * Lock an nfsnode
    */
   int
   nfs_lock(ap)
           struct vop_lock_args /* {
                   struct vnode *a_vp;
           } */ *ap;
   {
           register struct vnode *vp = ap->a_vp;
   
           /*
            * Ugh, another place where interruptible mounts will get hung.
            * If you make this sleep interruptible, then you have to fix all
            * the VOP_LOCK() calls to expect interruptibility.
            */
           while (vp->v_flag & VXLOCK) {
                   vp->v_flag |= VXWANT;
                   (void) tsleep((caddr_t)vp, PINOD, "nfslck", 0);
           }
           if (vp->v_tag == VT_NON)
                   return (ENOENT);
   
   #if 0
           /*
            * Only lock regular files.  If a server crashed while we were
            * holding a directory lock, we could easily end up sleeping
            * until the server rebooted while holding a lock on the root.
            * Locks are only needed for protecting critical sections in
            * VMIO at the moment.
            * New vnodes will have type VNON but they should be locked
            * since they may become VREG.  This is checked in loadattrcache
            * and unwanted locks are released there.
            */
           if (vp->v_type == VREG || vp->v_type == VNON) {
                   while (np->n_flag & NLOCKED) {
                           np->n_flag |= NWANTED;
                           (void) tsleep((caddr_t) np, PINOD, "nfslck2", 0);
                           /*
                            * If the vnode has transmuted into a VDIR while we
                            * were asleep, then skip the lock.
                            */
                           if (vp->v_type != VREG && vp->v_type != VNON)
                                   return (0);
                   }
                   np->n_flag |= NLOCKED;
           }
   #endif
   
           return (0);
   }
   
   /*
    * Unlock an nfsnode
    */
   int
   nfs_unlock(ap)
           struct vop_unlock_args /* {
                   struct vnode *a_vp;
           } */ *ap;
   {
   #if 0
           struct vnode* vp = ap->a_vp;
           struct nfsnode* np = VTONFS(vp);
   
           if (vp->v_type == VREG || vp->v_type == VNON) {
                   if (!(np->n_flag & NLOCKED))
                           panic("nfs_unlock: nfsnode not locked");
                   np->n_flag &= ~NLOCKED;
                   if (np->n_flag & NWANTED) {
                           np->n_flag &= ~NWANTED;
                           wakeup((caddr_t) np);
                   }
           }
   #endif
   
           return (0);
   }
   
   /*
    * Check for a locked nfsnode
    */
   int
   nfs_islocked(ap)
           struct vop_islocked_args /* {
                   struct vnode *a_vp;
                   struct proc *a_p;
           } */ *ap;
   {
           return VTONFS(ap->a_vp)->n_flag & NLOCKED ? 1 : 0;
   }
   #endif
   

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