sys/vfs/nfs/nfs_node.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Rick Macklem at The University of Guelph.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *      @(#)nfs_node.c  8.6 (Berkeley) 5/22/95
  33  * $FreeBSD: src/sys/nfs/nfs_node.c,v 1.36.2.3 2002/01/05 22:25:04 dillon Exp $
  34  */
  35
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/proc.h>
  40 #include <sys/mount.h>
  41 #include <sys/vnode.h>
  42 #include <sys/malloc.h>
  43 #include <sys/kernel.h>
  44 #include <sys/fnv_hash.h>
  45 #include <sys/objcache.h>
  46
  47 #include "rpcv2.h"
  48 #include "nfsproto.h"
  49 #include "nfs.h"
  50 #include "nfsmount.h"
  51 #include "nfsnode.h"
  52
  53 static struct lwkt_token nfsnhash_token =
  54                         LWKT_TOKEN_INITIALIZER(nfsnhash_token);
  55 static struct lock nfsnhash_lock;
  56 __read_mostly static LIST_HEAD(nfsnodehashhead, nfsnode) *nfsnodehashtbl;
  57 __read_mostly static u_long nfsnodehash;
  58
  59 #define TRUE    1
  60 #define FALSE   0
  61
  62 #define NFSNOHASH(fhsum)        (&nfsnodehashtbl[(fhsum) & nfsnodehash])
  63
  64 /*
  65  * Initialize hash links for nfsnodes
  66  * and build nfsnode free list.
  67  */
  68 void
  69 nfs_nhinit(void)
  70 {
  71         int hsize = vfs_inodehashsize();
  72
  73         nfsnodehashtbl = hashinit(hsize, M_NFS, &nfsnodehash);
  74         lockinit(&nfsnhash_lock, "nfsnht", 0, 0);
  75 }
  76
  77 void
  78 nfs_nhdestroy(void)
  79 {
  80         hashdestroy(nfsnodehashtbl, M_NFS, nfsnodehash);
  81 }
  82
  83 /*
  84  * Look up a vnode/nfsnode by file handle.
  85  * Callers must check for mount points!!
  86  * In all cases, a pointer to a
  87  * nfsnode structure is returned.
  88  */
  89
  90 int
  91 nfs_nget(struct mount *mntp, nfsfh_t *fhp, int fhsize, struct nfsnode **npp,
  92          struct vnode *notvp)
  93 {
  94         struct nfsnode *np, *np2;
  95         struct nfsnodehashhead *nhpp;
  96         struct vnode *vp;
  97         int error;
  98         int lkflags;
  99         struct nfsmount *nmp;
 100
 101         /*
 102          * Calculate nfs mount point and figure out whether the rslock should
 103          * be interruptable or not.
 104          */
 105         nmp = VFSTONFS(mntp);
 106         if (nmp->nm_flag & NFSMNT_INT)
 107                 lkflags = LK_PCATCH;
 108         else
 109                 lkflags = 0;
 110
 111         lwkt_gettoken(&nfsnhash_token);
 112
 113 retry:
 114         nhpp = NFSNOHASH(fnv_32_buf(fhp->fh_bytes, fhsize, FNV1_32_INIT));
 115 loop:
 116         LIST_FOREACH(np, nhpp, n_hash) {
 117                 if (mntp != NFSTOV(np)->v_mount || np->n_fhsize != fhsize ||
 118                     bcmp((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize)) {
 119                         continue;
 120                 }
 121                 vp = NFSTOV(np);
 122                 if (vp == notvp) {
 123                         kprintf("nfs warning: client-client collision "
 124                                 "during rename/link/softlink\n");
 125                         *npp = NULL;
 126                         lwkt_reltoken(&nfsnhash_token);
 127                         return (ESTALE);
 128                 }
 129                 if (vget(vp, LK_EXCLUSIVE))
 130                         goto loop;
 131                 LIST_FOREACH(np, nhpp, n_hash) {
 132                         if (mntp == NFSTOV(np)->v_mount &&
 133                             np->n_fhsize == fhsize &&
 134                             bcmp((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize) == 0
 135                         ) {
 136                                 break;
 137                         }
 138                 }
 139                 if (np == NULL || NFSTOV(np) != vp) {
 140                         vput(vp);
 141                         goto loop;
 142                 }
 143                 *npp = np;
 144                 lwkt_reltoken(&nfsnhash_token);
 145                 return(0);
 146         }
 147
 148         /*
 149          * Obtain a lock to prevent a race condition if the getnewvnode()
 150          * or MALLOC() below happens to block.
 151          */
 152         if (lockmgr(&nfsnhash_lock, LK_EXCLUSIVE | LK_SLEEPFAIL))
 153                 goto loop;
 154
 155         /*
 156          * Allocate before getnewvnode since doing so afterward
 157          * might cause a bogus v_data pointer to get dereferenced
 158          * elsewhere if objcache should block.
 159          */
 160         np = kmalloc_obj(sizeof(struct nfsnode), nmp->nm_mnode,
 161                          M_WAITOK|M_ZERO);
 162
 163         error = getnewvnode(VT_NFS, mntp, &vp, 0, 0);
 164         if (error) {
 165                 lockmgr(&nfsnhash_lock, LK_RELEASE);
 166                 *npp = NULL;
 167                 kfree_obj(np, nmp->nm_mnode);
 168                 lwkt_reltoken(&nfsnhash_token);
 169                 return (error);
 170         }
 171
 172         /*
 173          * Initialize most of (np).
 174          */
 175         bzero(np, sizeof (*np));
 176         if (fhsize > NFS_SMALLFH) {
 177                 np->n_fhp = kmalloc(fhsize, M_NFSBIGFH, M_WAITOK);
 178         } else {
 179                 np->n_fhp = &np->n_fh;
 180         }
 181         bcopy((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize);
 182         np->n_fhsize = fhsize;
 183         lockinit(&np->n_rslock, "nfrslk", 0, lkflags);
 184
 185         /*
 186          * Validate that we did not race another nfs_nget() due to blocking
 187          * here and there.
 188          */
 189         for (np2 = nhpp->lh_first; np2 != NULL; np2 = np2->n_hash.le_next) {
 190                 if (mntp != NFSTOV(np2)->v_mount || np2->n_fhsize != fhsize ||
 191                     bcmp((caddr_t)fhp, (caddr_t)np2->n_fhp, fhsize)) {
 192                         continue;
 193                 }
 194                 vx_put(vp);
 195                 lockmgr(&nfsnhash_lock, LK_RELEASE);
 196
 197                 if (np->n_fhsize > NFS_SMALLFH)
 198                         kfree((caddr_t)np->n_fhp, M_NFSBIGFH);
 199                 np->n_fhp = NULL;
 200                 kfree_obj(np, nmp->nm_mnode);
 201                 goto retry;
 202         }
 203
 204         /*
 205          * Finish connecting up (np, vp) and insert the nfsnode in the
 206          * hash for its new file handle.
 207          *
 208          * nvp is locked & refd so effectively so is np.
 209          */
 210         np->n_vnode = vp;
 211         vp->v_data = np;
 212         LIST_INSERT_HEAD(nhpp, np, n_hash);
 213         *npp = np;
 214         lockmgr(&nfsnhash_lock, LK_RELEASE);
 215         lwkt_reltoken(&nfsnhash_token);
 216         vx_downgrade(vp);
 217
 218         return (0);
 219 }
 220
 221 /*
 222  * Nonblocking version of nfs_nget()
 223  */
 224 int
 225 nfs_nget_nonblock(struct mount *mntp, nfsfh_t *fhp, int fhsize,
 226                   struct nfsnode **npp, struct vnode *notvp)
 227 {
 228         struct nfsnode *np, *np2;
 229         struct nfsnodehashhead *nhpp;
 230         struct vnode *vp;
 231         int error;
 232         int lkflags;
 233         struct nfsmount *nmp;
 234
 235         /*
 236          * Calculate nfs mount point and figure out whether the rslock should
 237          * be interruptable or not.
 238          */
 239         nmp = VFSTONFS(mntp);
 240         if (nmp->nm_flag & NFSMNT_INT)
 241                 lkflags = LK_PCATCH;
 242         else
 243                 lkflags = 0;
 244         vp = NULL;
 245         *npp = NULL;
 246
 247         lwkt_gettoken(&nfsnhash_token);
 248
 249 retry:
 250         nhpp = NFSNOHASH(fnv_32_buf(fhp->fh_bytes, fhsize, FNV1_32_INIT));
 251 loop:
 252         LIST_FOREACH(np, nhpp, n_hash) {
 253                 if (mntp != NFSTOV(np)->v_mount || np->n_fhsize != fhsize ||
 254                     bcmp((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize)) {
 255                         continue;
 256                 }
 257                 if (vp == NULL) {
 258                         vp = NFSTOV(np);
 259                         if (vp == notvp) {
 260                                 kprintf("nfs warning: client-client collision "
 261                                         "during rename/link/softlink\n");
 262                                 error = ESTALE;
 263                                 goto fail;
 264                         }
 265                         if (vget(vp, LK_EXCLUSIVE | LK_NOWAIT)) {
 266                                 error = EWOULDBLOCK;
 267                                 goto fail;
 268                         }
 269                         goto loop;
 270                 }
 271                 if (NFSTOV(np) != vp) {
 272                         vput(vp);
 273                         goto loop;
 274                 }
 275                 *npp = np;
 276                 lwkt_reltoken(&nfsnhash_token);
 277                 return(0);
 278         }
 279
 280         /*
 281          * Not found.  If we raced and had acquired a vp we have to release
 282          * it here.
 283          */
 284         if (vp) {
 285                 vput(vp);
 286                 vp = NULL;
 287         }
 288
 289         /*
 290          * Obtain a lock to prevent a race condition if the getnewvnode()
 291          * or MALLOC() below happens to block.
 292          */
 293         if (lockmgr(&nfsnhash_lock, LK_EXCLUSIVE | LK_SLEEPFAIL))
 294                 goto loop;
 295
 296         /*
 297          * Entry not found, allocate a new entry.
 298          *
 299          * Allocate before getnewvnode since doing so afterward
 300          * might cause a bogus v_data pointer to get dereferenced
 301          * elsewhere if objcache should block.
 302          */
 303         np = kmalloc_obj(sizeof(struct nfsnode), nmp->nm_mnode,
 304                          M_WAITOK|M_ZERO);
 305
 306         error = getnewvnode(VT_NFS, mntp, &vp, 0, 0);
 307         if (error) {
 308                 lockmgr(&nfsnhash_lock, LK_RELEASE);
 309                 kfree_obj(np, nmp->nm_mnode);
 310                 lwkt_reltoken(&nfsnhash_token);
 311                 return (error);
 312         }
 313
 314         /*
 315          * Initialize most of (np).
 316          */
 317         bzero(np, sizeof (*np));
 318         if (fhsize > NFS_SMALLFH) {
 319                 np->n_fhp = kmalloc(fhsize, M_NFSBIGFH, M_WAITOK);
 320         } else {
 321                 np->n_fhp = &np->n_fh;
 322         }
 323         bcopy((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize);
 324         np->n_fhsize = fhsize;
 325         lockinit(&np->n_rslock, "nfrslk", 0, lkflags);
 326
 327         /*
 328          * Validate that we did not race another nfs_nget() due to blocking
 329          * here and there.
 330          */
 331         for (np2 = nhpp->lh_first; np2 != NULL; np2 = np2->n_hash.le_next) {
 332                 if (mntp != NFSTOV(np2)->v_mount || np2->n_fhsize != fhsize ||
 333                     bcmp((caddr_t)fhp, (caddr_t)np2->n_fhp, fhsize)) {
 334                         continue;
 335                 }
 336                 vx_put(vp);
 337                 lockmgr(&nfsnhash_lock, LK_RELEASE);
 338
 339                 if (np->n_fhsize > NFS_SMALLFH)
 340                         kfree((caddr_t)np->n_fhp, M_NFSBIGFH);
 341                 np->n_fhp = NULL;
 342                 kfree_obj(np, nmp->nm_mnode);
 343
 344                 /*
 345                  * vp state is retained on retry/loop so we must NULL it
 346                  * out here or fireworks may ensue.
 347                  */
 348                 vp = NULL;
 349                 goto retry;
 350         }
 351
 352         /*
 353          * Finish connecting up (np, vp) and insert the nfsnode in the
 354          * hash for its new file handle.
 355          *
 356          * nvp is locked & refd so effectively so is np.
 357          */
 358         np->n_vnode = vp;
 359         vp->v_data = np;
 360         LIST_INSERT_HEAD(nhpp, np, n_hash);
 361
 362         /*
 363          * nvp is locked & refd so effectively so is np.
 364          */
 365         *npp = np;
 366         error = 0;
 367         lockmgr(&nfsnhash_lock, LK_RELEASE);
 368         vx_downgrade(vp);
 369 fail:
 370         lwkt_reltoken(&nfsnhash_token);
 371         return (error);
 372 }
 373
 374 /*
 375  * nfs_inactive(struct vnode *a_vp)
 376  *
 377  * NOTE: the passed vnode is locked but not referenced.  On return the
 378  * vnode must be unlocked and not referenced.
 379  */
 380 int
 381 nfs_inactive(struct vop_inactive_args *ap)
 382 {
 383         struct nfsmount *nmp = VFSTONFS(ap->a_vp->v_mount);
 384         struct nfsnode *np;
 385         struct sillyrename *sp;
 386
 387         lwkt_gettoken(&nmp->nm_token);
 388
 389         np = VTONFS(ap->a_vp);
 390         if (prtactive && VREFCNT(ap->a_vp) > 1)
 391                 vprint("nfs_inactive: pushing active", ap->a_vp);
 392         if (ap->a_vp->v_type != VDIR) {
 393                 sp = np->n_sillyrename;
 394                 np->n_sillyrename = NULL;
 395         } else {
 396                 sp = NULL;
 397         }
 398         if (sp) {
 399                 /*
 400                  * We need a reference to keep the vnode from being
 401                  * recycled by getnewvnode while we do the I/O
 402                  * associated with discarding the buffers.  The vnode
 403                  * is already locked.
 404                  */
 405                 nfs_vinvalbuf(ap->a_vp, 0, 1);
 406
 407                 /*
 408                  * Remove the silly file that was rename'd earlier
 409                  */
 410                 nfs_removeit(sp);
 411                 crfree(sp->s_cred);
 412                 vrele(sp->s_dvp);
 413                 kfree((caddr_t)sp, M_NFSREQ);
 414         }
 415
 416         np->n_flag &= ~(NWRITEERR | NACC | NUPD | NCHG | NLOCKED | NWANTED);
 417         if (np->n_flag & NREMOVED)
 418                 vrecycle(ap->a_vp);
 419         lwkt_reltoken(&nmp->nm_token);
 420
 421         return (0);
 422 }
 423
 424 /*
 425  * Reclaim an nfsnode so that it can be used for other purposes.
 426  *
 427  * There should be no direct references to the related nfs node
 428  * since nobody is holding the vnode any more, other than hash
 429  * lookups which are interlocked against nfsnhash_token and vget().
 430  *
 431  * nfs_reclaim(struct vnode *a_vp)
 432  */
 433 int
 434 nfs_reclaim(struct vop_reclaim_args *ap)
 435 {
 436         struct vnode *vp = ap->a_vp;
 437         struct nfsnode *np = VTONFS(vp);
 438         struct nfsdmap *dp, *dp2;
 439         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
 440
 441         if (prtactive && VREFCNT(vp) > 1)
 442                 vprint("nfs_reclaim: pushing active", vp);
 443
 444
 445         /*
 446          * Remove from hash table and remove the cross links.
 447          *
 448          * NOTE: Other NFS code may look up a np and vget() the
 449          *       related vnode, then will check np->n_vnode.
 450          *       We must clear np->n_vnode here to ensure that all
 451          *       possible races are dealt with.
 452          */
 453         lwkt_gettoken(&nfsnhash_token);
 454         KKASSERT(np->n_vnode == vp);
 455         if (np->n_hash.le_prev != NULL)
 456                 LIST_REMOVE(np, n_hash);
 457         np->n_vnode = NULL;
 458         vp->v_data = NULL;
 459         lwkt_reltoken(&nfsnhash_token);
 460
 461         /*
 462          * Free up any directory cookie structures and
 463          * large file handle structures that might be associated with
 464          * this nfs node.
 465          */
 466         if (vp->v_type == VDIR) {
 467                 dp = np->n_cookies.lh_first;
 468                 while (dp) {
 469                         dp2 = dp;
 470                         dp = dp->ndm_list.le_next;
 471                         kfree((caddr_t)dp2, M_NFSDIROFF);
 472                 }
 473         }
 474         if (np->n_fhsize > NFS_SMALLFH) {
 475                 kfree((caddr_t)np->n_fhp, M_NFSBIGFH);
 476         }
 477         if (np->n_rucred) {
 478                 crfree(np->n_rucred);
 479                 np->n_rucred = NULL;
 480         }
 481         if (np->n_wucred) {
 482                 crfree(np->n_wucred);
 483                 np->n_wucred = NULL;
 484         }
 485         kfree_obj(np, nmp->nm_mnode);
 486
 487         return (0);
 488 }
 489