sys/vfs/hammer2/hammer2_inode.c

   1 /*
   2  * Copyright (c) 2011-2013 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
   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  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35 #include <sys/cdefs.h>
  36 #include <sys/param.h>
  37 #include <sys/systm.h>
  38 #include <sys/types.h>
  39 #include <sys/lock.h>
  40 #include <sys/uuid.h>
  41
  42 #include "hammer2.h"
  43
  44 RB_GENERATE2(hammer2_inode_tree, hammer2_inode, rbnode, hammer2_inode_cmp,
  45              hammer2_tid_t, inum);
  46
  47 int
  48 hammer2_inode_cmp(hammer2_inode_t *ip1, hammer2_inode_t *ip2)
  49 {
  50         if (ip1->inum < ip2->inum)
  51                 return(-1);
  52         if (ip1->inum > ip2->inum)
  53                 return(1);
  54         return(0);
  55 }
  56
  57 /*
  58  * HAMMER2 inode locks
  59  *
  60  * HAMMER2 offers shared locks and exclusive locks on inodes.
  61  *
  62  * An inode's ip->chain pointer is resolved and stable while an inode is
  63  * locked, and can be cleaned out at any time (become NULL) when an inode
  64  * is not locked.
  65  *
  66  * The underlying chain is also locked and returned.
  67  *
  68  * NOTE: We don't combine the inode/chain lock because putting away an
  69  *       inode would otherwise confuse multiple lock holders of the inode.
  70  */
  71 hammer2_chain_t *
  72 hammer2_inode_lock_ex(hammer2_inode_t *ip)
  73 {
  74         hammer2_chain_t *chain;
  75
  76         hammer2_inode_ref(ip);
  77         ccms_thread_lock(&ip->topo_cst, CCMS_STATE_EXCLUSIVE);
  78
  79         /*
  80          * ip->chain fixup.  Certain duplications used to move inodes
  81          * into indirect blocks (for example) can cause ip->chain to
  82          * become stale.
  83          */
  84 again:
  85         chain = ip->chain;
  86         if (hammer2_chain_refactor_test(chain, 1)) {
  87                 spin_lock(&chain->core->cst.spin);
  88                 while (hammer2_chain_refactor_test(chain, 1))
  89                         chain = chain->next_parent;
  90                 if (ip->chain != chain) {
  91                         hammer2_chain_ref(chain);
  92                         spin_unlock(&chain->core->cst.spin);
  93                         hammer2_inode_repoint(ip, NULL, chain);
  94                         hammer2_chain_drop(chain);
  95                 } else {
  96                         spin_unlock(&chain->core->cst.spin);
  97                 }
  98         }
  99
 100         KKASSERT(chain != NULL);        /* for now */
 101         hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
 102
 103         /*
 104          * Resolve duplication races
 105          */
 106         if (hammer2_chain_refactor_test(chain, 1)) {
 107                 hammer2_chain_unlock(chain);
 108                 goto again;
 109         }
 110         return (chain);
 111 }
 112
 113 void
 114 hammer2_inode_unlock_ex(hammer2_inode_t *ip, hammer2_chain_t *chain)
 115 {
 116         /*
 117          * XXX this will catch parent directories too which we don't
 118          *     really want.
 119          */
 120         if (chain)
 121                 hammer2_chain_unlock(chain);
 122         ccms_thread_unlock(&ip->topo_cst);
 123         hammer2_inode_drop(ip);
 124 }
 125
 126 /*
 127  * NOTE: We don't combine the inode/chain lock because putting away an
 128  *       inode would otherwise confuse multiple lock holders of the inode.
 129  *
 130  *       Shared locks are especially sensitive to having too many shared
 131  *       lock counts (from the same thread) on certain paths which might
 132  *       need to upgrade them.  Only one count of a shared lock can be
 133  *       upgraded.
 134  */
 135 hammer2_chain_t *
 136 hammer2_inode_lock_sh(hammer2_inode_t *ip)
 137 {
 138         hammer2_chain_t *chain;
 139
 140         hammer2_inode_ref(ip);
 141 again:
 142         ccms_thread_lock(&ip->topo_cst, CCMS_STATE_SHARED);
 143
 144         chain = ip->chain;
 145         KKASSERT(chain != NULL);        /* for now */
 146         hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS |
 147                                   HAMMER2_RESOLVE_SHARED);
 148
 149         /*
 150          * Resolve duplication races
 151          */
 152         if (hammer2_chain_refactor_test(chain, 1)) {
 153                 hammer2_chain_unlock(chain);
 154                 ccms_thread_unlock(&ip->topo_cst);
 155                 chain = hammer2_inode_lock_ex(ip);
 156                 hammer2_inode_unlock_ex(ip, chain);
 157                 goto again;
 158         }
 159         return (chain);
 160 }
 161
 162 void
 163 hammer2_inode_unlock_sh(hammer2_inode_t *ip, hammer2_chain_t *chain)
 164 {
 165         if (chain)
 166                 hammer2_chain_unlock(chain);
 167         ccms_thread_unlock(&ip->topo_cst);
 168         hammer2_inode_drop(ip);
 169 }
 170
 171 ccms_state_t
 172 hammer2_inode_lock_temp_release(hammer2_inode_t *ip)
 173 {
 174         return(ccms_thread_lock_temp_release(&ip->topo_cst));
 175 }
 176
 177 void
 178 hammer2_inode_lock_temp_restore(hammer2_inode_t *ip, ccms_state_t ostate)
 179 {
 180         ccms_thread_lock_temp_restore(&ip->topo_cst, ostate);
 181 }
 182
 183 ccms_state_t
 184 hammer2_inode_lock_upgrade(hammer2_inode_t *ip)
 185 {
 186         return(ccms_thread_lock_upgrade(&ip->topo_cst));
 187 }
 188
 189 void
 190 hammer2_inode_lock_downgrade(hammer2_inode_t *ip, ccms_state_t ostate)
 191 {
 192         ccms_thread_lock_downgrade(&ip->topo_cst, ostate);
 193 }
 194
 195 /*
 196  * Lookup an inode by inode number
 197  */
 198 hammer2_inode_t *
 199 hammer2_inode_lookup(hammer2_pfsmount_t *pmp, hammer2_tid_t inum)
 200 {
 201         hammer2_inode_t *ip;
 202
 203         if (pmp) {
 204                 spin_lock(&pmp->inum_spin);
 205                 ip = RB_LOOKUP(hammer2_inode_tree, &pmp->inum_tree, inum);
 206                 if (ip)
 207                         hammer2_inode_ref(ip);
 208                 spin_unlock(&pmp->inum_spin);
 209         } else {
 210                 ip = NULL;
 211         }
 212         return(ip);
 213 }
 214
 215 /*
 216  * Adding a ref to an inode is only legal if the inode already has at least
 217  * one ref.
 218  */
 219 void
 220 hammer2_inode_ref(hammer2_inode_t *ip)
 221 {
 222         atomic_add_int(&ip->refs, 1);
 223 }
 224
 225 /*
 226  * Drop an inode reference, freeing the inode when the last reference goes
 227  * away.
 228  */
 229 void
 230 hammer2_inode_drop(hammer2_inode_t *ip)
 231 {
 232         hammer2_mount_t *hmp;
 233         hammer2_inode_t *pip;
 234         u_int refs;
 235
 236         while (ip) {
 237                 refs = ip->refs;
 238                 cpu_ccfence();
 239                 if (refs == 1) {
 240                         /*
 241                          * Transition to zero, must interlock with
 242                          * the inode inumber lookup tree (if applicable).
 243                          *
 244                          * NOTE: The super-root inode has no pmp.
 245                          */
 246                         if (ip->pmp)
 247                                 spin_lock(&ip->pmp->inum_spin);
 248
 249                         if (atomic_cmpset_int(&ip->refs, 1, 0)) {
 250                                 KKASSERT(ip->topo_cst.count == 0);
 251                                 if (ip->flags & HAMMER2_INODE_ONRBTREE) {
 252                                         atomic_clear_int(&ip->flags,
 253                                                      HAMMER2_INODE_ONRBTREE);
 254                                         RB_REMOVE(hammer2_inode_tree,
 255                                                   &ip->pmp->inum_tree,
 256                                                   ip);
 257                                 }
 258                                 if (ip->pmp)
 259                                         spin_unlock(&ip->pmp->inum_spin);
 260
 261                                 hmp = ip->hmp;
 262                                 ip->hmp = NULL;
 263                                 pip = ip->pip;
 264                                 ip->pip = NULL;
 265
 266                                 /*
 267                                  * Cleaning out ip->chain isn't entirely
 268                                  * trivial.
 269                                  */
 270                                 hammer2_inode_repoint(ip, NULL, NULL);
 271
 272                                 /*
 273                                  * We have to drop pip (if non-NULL) to
 274                                  * dispose of our implied reference from
 275                                  * ip->pip.  We can simply loop on it.
 276                                  */
 277                                 kfree(ip, hmp->minode);
 278                                 ip = pip;
 279                                 /* continue with pip (can be NULL) */
 280                         } else {
 281                                 if (ip->pmp)
 282                                         spin_unlock(&ip->pmp->inum_spin);
 283                         }
 284                 } else {
 285                         /*
 286                          * Non zero transition
 287                          */
 288                         if (atomic_cmpset_int(&ip->refs, refs, refs - 1))
 289                                 break;
 290                 }
 291         }
 292 }
 293
 294 /*
 295  * Get the vnode associated with the given inode, allocating the vnode if
 296  * necessary.  The vnode will be returned exclusively locked.
 297  *
 298  * The caller must lock the inode (shared or exclusive).
 299  *
 300  * Great care must be taken to avoid deadlocks and vnode acquisition/reclaim
 301  * races.
 302  */
 303 struct vnode *
 304 hammer2_igetv(hammer2_inode_t *ip, int *errorp)
 305 {
 306         hammer2_inode_data_t *ipdata;
 307         hammer2_pfsmount_t *pmp;
 308         struct vnode *vp;
 309         ccms_state_t ostate;
 310
 311         pmp = ip->pmp;
 312         KKASSERT(pmp != NULL);
 313         *errorp = 0;
 314         ipdata = &ip->chain->data->ipdata;
 315
 316         for (;;) {
 317                 /*
 318                  * Attempt to reuse an existing vnode assignment.  It is
 319                  * possible to race a reclaim so the vget() may fail.  The
 320                  * inode must be unlocked during the vget() to avoid a
 321                  * deadlock against a reclaim.
 322                  */
 323                 vp = ip->vp;
 324                 if (vp) {
 325                         /*
 326                          * Inode must be unlocked during the vget() to avoid
 327                          * possible deadlocks, but leave the ip ref intact.
 328                          *
 329                          * vnode is held to prevent destruction during the
 330                          * vget().  The vget() can still fail if we lost
 331                          * a reclaim race on the vnode.
 332                          */
 333                         vhold_interlocked(vp);
 334                         ostate = hammer2_inode_lock_temp_release(ip);
 335                         if (vget(vp, LK_EXCLUSIVE)) {
 336                                 vdrop(vp);
 337                                 hammer2_inode_lock_temp_restore(ip, ostate);
 338                                 continue;
 339                         }
 340                         hammer2_inode_lock_temp_restore(ip, ostate);
 341                         vdrop(vp);
 342                         /* vp still locked and ref from vget */
 343                         if (ip->vp != vp) {
 344                                 kprintf("hammer2: igetv race %p/%p\n",
 345                                         ip->vp, vp);
 346                                 vput(vp);
 347                                 continue;
 348                         }
 349                         *errorp = 0;
 350                         break;
 351                 }
 352
 353                 /*
 354                  * No vnode exists, allocate a new vnode.  Beware of
 355                  * allocation races.  This function will return an
 356                  * exclusively locked and referenced vnode.
 357                  */
 358                 *errorp = getnewvnode(VT_HAMMER2, pmp->mp, &vp, 0, 0);
 359                 if (*errorp) {
 360                         kprintf("hammer2: igetv getnewvnode failed %d\n",
 361                                 *errorp);
 362                         vp = NULL;
 363                         break;
 364                 }
 365
 366                 /*
 367                  * Lock the inode and check for an allocation race.
 368                  */
 369                 ostate = hammer2_inode_lock_upgrade(ip);
 370                 if (ip->vp != NULL) {
 371                         vp->v_type = VBAD;
 372                         vx_put(vp);
 373                         hammer2_inode_lock_downgrade(ip, ostate);
 374                         continue;
 375                 }
 376
 377                 switch (ipdata->type) {
 378                 case HAMMER2_OBJTYPE_DIRECTORY:
 379                         vp->v_type = VDIR;
 380                         break;
 381                 case HAMMER2_OBJTYPE_REGFILE:
 382                         vp->v_type = VREG;
 383                         vinitvmio(vp, ipdata->size,
 384                                   HAMMER2_LBUFSIZE,
 385                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 386                         break;
 387                 case HAMMER2_OBJTYPE_SOFTLINK:
 388                         /*
 389                          * XXX for now we are using the generic file_read
 390                          * and file_write code so we need a buffer cache
 391                          * association.
 392                          */
 393                         vp->v_type = VLNK;
 394                         vinitvmio(vp, ipdata->size,
 395                                   HAMMER2_LBUFSIZE,
 396                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 397                         break;
 398                 /* XXX FIFO */
 399                 default:
 400                         panic("hammer2: unhandled objtype %d", ipdata->type);
 401                         break;
 402                 }
 403
 404                 if (ip == pmp->iroot)
 405                         vsetflags(vp, VROOT);
 406
 407                 vp->v_data = ip;
 408                 ip->vp = vp;
 409                 hammer2_inode_ref(ip);          /* vp association */
 410                 hammer2_inode_lock_downgrade(ip, ostate);
 411                 break;
 412         }
 413
 414         /*
 415          * Return non-NULL vp and *errorp == 0, or NULL vp and *errorp != 0.
 416          */
 417         if (hammer2_debug & 0x0002) {
 418                 kprintf("igetv vp %p refs %d aux %d\n",
 419                         vp, vp->v_sysref.refcnt, vp->v_auxrefs);
 420         }
 421         return (vp);
 422 }
 423
 424 /*
 425  * The passed-in chain must be locked and the returned inode will also be
 426  * locked.  This routine typically locates or allocates the inode, assigns
 427  * ip->chain (adding a ref to chain if necessary), and returns the inode.
 428  *
 429  * The hammer2_inode structure regulates the interface between the high level
 430  * kernel VNOPS API and the filesystem backend (the chains).
 431  *
 432  * WARNING!  This routine sucks up the chain's lock (makes it part of the
 433  *           inode lock from the point of view of the inode lock API),
 434  *           so callers need to be careful.
 435  *
 436  * WARNING!  The mount code is allowed to pass dip == NULL for iroot and
 437  *           is allowed to pass pmp == NULL and dip == NULL for sroot.
 438  */
 439 hammer2_inode_t *
 440 hammer2_inode_get(hammer2_mount_t *hmp, hammer2_pfsmount_t *pmp,
 441                   hammer2_inode_t *dip, hammer2_chain_t *chain)
 442 {
 443         hammer2_inode_t *nip;
 444
 445         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
 446
 447         /*
 448          * Interlocked lookup/ref of the inode.  This code is only needed
 449          * when looking up inodes with nlinks != 0 (TODO: optimize out
 450          * otherwise and test for duplicates).
 451          */
 452 again:
 453         for (;;) {
 454                 nip = hammer2_inode_lookup(pmp, chain->data->ipdata.inum);
 455                 if (nip == NULL)
 456                         break;
 457                 ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 458                 if ((nip->flags & HAMMER2_INODE_ONRBTREE) == 0) { /* race */
 459                         ccms_thread_unlock(&nip->topo_cst);
 460                         hammer2_inode_drop(nip);
 461                         continue;
 462                 }
 463                 if (nip->chain != chain)
 464                         hammer2_inode_repoint(nip, NULL, chain);
 465
 466                 /*
 467                  * Consolidated nip/nip->chain is locked (chain locked
 468                  * by caller).
 469                  */
 470                 return nip;
 471         }
 472
 473         /*
 474          * We couldn't find the inode number, create a new inode.
 475          */
 476         nip = kmalloc(sizeof(*nip), hmp->minode, M_WAITOK | M_ZERO);
 477         nip->inum = chain->data->ipdata.inum;
 478         hammer2_inode_repoint(nip, NULL, chain);
 479         nip->pip = dip;                         /* can be NULL */
 480         if (dip)
 481                 hammer2_inode_ref(dip); /* ref dip for nip->pip */
 482
 483         nip->pmp = pmp;
 484         nip->hmp = hmp;
 485
 486         /*
 487          * ref and lock on nip gives it state compatible to after a
 488          * hammer2_inode_lock_ex() call.
 489          */
 490         nip->refs = 1;
 491         ccms_cst_init(&nip->topo_cst, &nip->chain);
 492         ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 493         /* combination of thread lock and chain lock == inode lock */
 494
 495         /*
 496          * Attempt to add the inode.  If it fails we raced another inode
 497          * get.  Undo all the work and try again.
 498          */
 499         if (pmp) {
 500                 spin_lock(&pmp->inum_spin);
 501                 if (RB_INSERT(hammer2_inode_tree, &pmp->inum_tree, nip)) {
 502                         spin_unlock(&pmp->inum_spin);
 503                         ccms_thread_unlock(&nip->topo_cst);
 504                         hammer2_inode_drop(nip);
 505                         goto again;
 506                 }
 507                 atomic_set_int(&nip->flags, HAMMER2_INODE_ONRBTREE);
 508                 spin_unlock(&pmp->inum_spin);
 509         }
 510
 511         return (nip);
 512 }
 513
 514 /*
 515  * Create a new inode in the specified directory using the vattr to
 516  * figure out the type of inode.
 517  *
 518  * If no error occurs the new inode with its chain locked is returned in
 519  * *nipp, otherwise an error is returned and *nipp is set to NULL.
 520  *
 521  * If vap and/or cred are NULL the related fields are not set and the
 522  * inode type defaults to a directory.  This is used when creating PFSs
 523  * under the super-root, so the inode number is set to 1 in this case.
 524  *
 525  * dip is not locked on entry.
 526  */
 527 hammer2_inode_t *
 528 hammer2_inode_create(hammer2_trans_t *trans, hammer2_inode_t *dip,
 529                      struct vattr *vap, struct ucred *cred,
 530                      const uint8_t *name, size_t name_len,
 531                      hammer2_chain_t **chainp, int *errorp)
 532 {
 533         hammer2_inode_data_t *dipdata;
 534         hammer2_inode_data_t *nipdata;
 535         hammer2_mount_t *hmp;
 536         hammer2_chain_t *chain;
 537         hammer2_chain_t *parent;
 538         hammer2_inode_t *nip;
 539         hammer2_key_t lhc;
 540         int error;
 541         uid_t xuid;
 542         uuid_t dip_uid;
 543         uuid_t dip_gid;
 544         uint32_t dip_mode;
 545
 546         hmp = dip->hmp;
 547         lhc = hammer2_dirhash(name, name_len);
 548         *errorp = 0;
 549
 550         /*
 551          * Locate the inode or indirect block to create the new
 552          * entry in.  At the same time check for key collisions
 553          * and iterate until we don't get one.
 554          *
 555          * NOTE: hidden inodes do not have iterators.
 556          */
 557 retry:
 558         parent = hammer2_inode_lock_ex(dip);
 559         dipdata = &dip->chain->data->ipdata;
 560         dip_uid = dipdata->uid;
 561         dip_gid = dipdata->gid;
 562         dip_mode = dipdata->mode;
 563
 564         error = 0;
 565         while (error == 0) {
 566                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 567                 if (chain == NULL)
 568                         break;
 569                 if ((lhc & HAMMER2_DIRHASH_VISIBLE) == 0)
 570                         error = ENOSPC;
 571                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 572                         error = ENOSPC;
 573                 hammer2_chain_unlock(chain);
 574                 chain = NULL;
 575                 ++lhc;
 576         }
 577         if (error == 0) {
 578                 error = hammer2_chain_create(trans, &parent, &chain,
 579                                              lhc, 0,
 580                                              HAMMER2_BREF_TYPE_INODE,
 581                                              HAMMER2_INODE_BYTES);
 582         }
 583
 584         /*
 585          * Cleanup and handle retries.
 586          */
 587         if (error == EAGAIN) {
 588                 hammer2_chain_ref(parent);
 589                 hammer2_inode_unlock_ex(dip, parent);
 590                 hammer2_chain_wait(parent);
 591                 hammer2_chain_drop(parent);
 592                 goto retry;
 593         }
 594         hammer2_inode_unlock_ex(dip, parent);
 595
 596         if (error) {
 597                 KKASSERT(chain == NULL);
 598                 *errorp = error;
 599                 return (NULL);
 600         }
 601
 602         /*
 603          * Set up the new inode.
 604          *
 605          * NOTE: *_get() integrates chain's lock into the inode lock.
 606          *
 607          * NOTE: Only one new inode can currently be created per
 608          *       transaction.  If the need arises we can adjust
 609          *       hammer2_trans_init() to allow more.
 610          */
 611         chain->data->ipdata.inum = trans->sync_tid;
 612         nip = hammer2_inode_get(dip->hmp, dip->pmp, dip, chain);
 613         nipdata = &chain->data->ipdata;
 614
 615         if (vap) {
 616                 KKASSERT(trans->inodes_created == 0);
 617                 nipdata->type = hammer2_get_obj_type(vap->va_type);
 618                 nipdata->inum = trans->sync_tid;
 619                 ++trans->inodes_created;
 620         } else {
 621                 nipdata->type = HAMMER2_OBJTYPE_DIRECTORY;
 622                 nipdata->inum = 1;
 623         }
 624         nipdata->version = HAMMER2_INODE_VERSION_ONE;
 625         hammer2_update_time(&nipdata->ctime);
 626         nipdata->mtime = nipdata->ctime;
 627         if (vap)
 628                 nipdata->mode = vap->va_mode;
 629         nipdata->nlinks = 1;
 630         if (vap) {
 631                 if (dip) {
 632                         xuid = hammer2_to_unix_xid(&dip_uid);
 633                         xuid = vop_helper_create_uid(dip->pmp->mp,
 634                                                      dip_mode,
 635                                                      xuid,
 636                                                      cred,
 637                                                      &vap->va_mode);
 638                 } else {
 639                         xuid = 0;
 640                 }
 641                 if (vap->va_vaflags & VA_UID_UUID_VALID)
 642                         nipdata->uid = vap->va_uid_uuid;
 643                 else if (vap->va_uid != (uid_t)VNOVAL)
 644                         hammer2_guid_to_uuid(&nipdata->uid, vap->va_uid);
 645                 else
 646                         hammer2_guid_to_uuid(&nipdata->uid, xuid);
 647
 648                 if (vap->va_vaflags & VA_GID_UUID_VALID)
 649                         nipdata->gid = vap->va_gid_uuid;
 650                 else if (vap->va_gid != (gid_t)VNOVAL)
 651                         hammer2_guid_to_uuid(&nipdata->gid, vap->va_gid);
 652                 else if (dip)
 653                         nipdata->gid = dip_gid;
 654         }
 655
 656         /*
 657          * Regular files and softlinks allow a small amount of data to be
 658          * directly embedded in the inode.  This flag will be cleared if
 659          * the size is extended past the embedded limit.
 660          */
 661         if (nipdata->type == HAMMER2_OBJTYPE_REGFILE ||
 662             nipdata->type == HAMMER2_OBJTYPE_SOFTLINK) {
 663                 nipdata->op_flags |= HAMMER2_OPFLAG_DIRECTDATA;
 664         }
 665
 666         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 667         bcopy(name, nipdata->filename, name_len);
 668         nipdata->name_key = lhc;
 669         nipdata->name_len = name_len;
 670         *chainp = chain;
 671
 672         return (nip);
 673 }
 674
 675 /*
 676  * chain may have been moved around by the create.
 677  */
 678 static
 679 void
 680 hammer2_chain_refactor(hammer2_chain_t **chainp)
 681 {
 682         hammer2_chain_t *chain = *chainp;
 683         hammer2_chain_core_t *core;
 684
 685         core = chain->core;
 686         spin_lock(&core->cst.spin);
 687         while (hammer2_chain_refactor_test(chain, 1)) {
 688                 chain = chain->next_parent;
 689                 while (hammer2_chain_refactor_test(chain, 1))
 690                         chain = chain->next_parent;
 691                 hammer2_chain_ref(chain);
 692                 spin_unlock(&core->cst.spin);
 693
 694                 hammer2_chain_unlock(*chainp);
 695                 hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS |
 696                                           HAMMER2_RESOLVE_NOREF); /* eat ref */
 697                 *chainp = chain;
 698                 spin_lock(&core->cst.spin);
 699         }
 700         spin_unlock(&core->cst.spin);
 701 }
 702
 703 /*
 704  * ochain represents the target file inode.  We need to move it to the
 705  * specified common parent directory (dip) and rename it to a special
 706  * invisible "0xINODENUMBER" filename.
 707  *
 708  * We use chain_duplicate and duplicate ochain at the new location,
 709  * renaming it appropriately.  We create a temporary chain and
 710  * then delete it to placemark where the duplicate will go.  Both of
 711  * these use the inode number for (lhc) (the key), generating the
 712  * invisible filename.
 713  */
 714 static
 715 hammer2_chain_t *
 716 hammer2_hardlink_shiftup(hammer2_trans_t *trans, hammer2_chain_t **ochainp,
 717                         hammer2_inode_t *dip, int *errorp)
 718 {
 719         hammer2_inode_data_t *nipdata;
 720         hammer2_mount_t *hmp;
 721         hammer2_chain_t *parent;
 722         hammer2_chain_t *ochain;
 723         hammer2_chain_t *nchain;
 724         hammer2_chain_t *tmp;
 725         hammer2_key_t lhc;
 726         hammer2_blockref_t bref;
 727
 728         ochain = *ochainp;
 729         *errorp = 0;
 730         hmp = dip->hmp;
 731         lhc = ochain->data->ipdata.inum;
 732         KKASSERT((lhc & HAMMER2_DIRHASH_VISIBLE) == 0);
 733
 734         /*
 735          * Locate the inode or indirect block to create the new
 736          * entry in.  lhc represents the inode number so there is
 737          * no collision iteration.
 738          *
 739          * There should be no key collisions with invisible inode keys.
 740          */
 741 retry:
 742         parent = hammer2_chain_lookup_init(dip->chain, 0);
 743         nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 744         if (nchain) {
 745                 kprintf("X3 chain %p parent %p dip %p dip->chain %p\n",
 746                         nchain, parent, dip, dip->chain);
 747                 hammer2_chain_unlock(nchain);
 748                 nchain = NULL;
 749                 *errorp = ENOSPC;
 750 #if 1
 751                 Debugger("X3");
 752 #endif
 753         }
 754
 755         /*
 756          * Create entry in common parent directory using the seek position
 757          * calculated above.
 758          */
 759         if (*errorp == 0) {
 760                 KKASSERT(nchain == NULL);
 761                 *errorp = hammer2_chain_create(trans, &parent, &nchain,
 762                                                lhc, 0,
 763                                                HAMMER2_BREF_TYPE_INODE,/* n/a */
 764                                                HAMMER2_INODE_BYTES);   /* n/a */
 765                 hammer2_chain_refactor(&ochain);
 766                 *ochainp = ochain;
 767         }
 768
 769         /*
 770          * Cleanup and handle retries.
 771          */
 772         if (*errorp == EAGAIN) {
 773                 hammer2_chain_ref(parent);
 774                 hammer2_chain_lookup_done(parent);
 775                 hammer2_chain_wait(parent);
 776                 hammer2_chain_drop(parent);
 777                 goto retry;
 778         }
 779
 780         /*
 781          * Handle the error case
 782          */
 783         if (*errorp) {
 784                 KKASSERT(nchain == NULL);
 785                 hammer2_chain_lookup_done(parent);
 786                 return (NULL);
 787         }
 788
 789         /*
 790          * Use chain as a placeholder for (lhc), delete it and replace
 791          * it with our duplication.
 792          *
 793          * Gain a second lock on ochain for the duplication function to
 794          * unlock, maintain the caller's original lock across the call.
 795          *
 796          * This is a bit messy.
 797          */
 798         hammer2_chain_delete(trans, nchain);
 799         hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
 800         tmp = ochain;
 801         bref = tmp->bref;
 802         bref.key = lhc;                 /* invisible dir entry key */
 803         bref.keybits = 0;
 804         hammer2_chain_duplicate(trans, parent, nchain->index, &tmp, &bref);
 805         hammer2_chain_lookup_done(parent);
 806         hammer2_chain_unlock(nchain);   /* no longer needed */
 807
 808         /*
 809          * Now set chain to our duplicate and modify it appropriately.
 810          *
 811          * Directory entries are inodes but this is a hidden hardlink
 812          * target.  The name isn't used but to ease debugging give it
 813          * a name after its inode number.
 814          */
 815         nchain = tmp;
 816         tmp = NULL;     /* safety */
 817
 818         hammer2_chain_modify(trans, &nchain, HAMMER2_MODIFY_ASSERTNOCOPY);
 819         nipdata = &nchain->data->ipdata;
 820         ksnprintf(nipdata->filename, sizeof(nipdata->filename),
 821                   "0x%016jx", (intmax_t)nipdata->inum);
 822         nipdata->name_len = strlen(nipdata->filename);
 823         nipdata->name_key = lhc;
 824
 825         return (nchain);
 826 }
 827
 828 /*
 829  * Connect the target inode represented by (*chainp) to the media topology
 830  * at (dip, name, len).
 831  *
 832  * If hlink is TRUE this function creates an OBJTYPE_HARDLINK directory
 833  * entry instead of connecting (*chainp).
 834  *
 835  * If hlink is FALSE this function uses chain_duplicate() to make a copy
 836  * if (*chainp) in the directory entry.  (*chainp) is likely to be deleted
 837  * by the caller in this case (e.g. rename).
 838  */
 839 int
 840 hammer2_inode_connect(hammer2_trans_t *trans, int hlink,
 841                       hammer2_inode_t *dip, hammer2_chain_t **chainp,
 842                       const uint8_t *name, size_t name_len)
 843 {
 844         hammer2_inode_data_t *ipdata;
 845         hammer2_mount_t *hmp;
 846         hammer2_chain_t *nchain;
 847         hammer2_chain_t *parent;
 848         hammer2_chain_t *ochain;
 849         hammer2_key_t lhc;
 850         int error;
 851
 852         hmp = dip->hmp;
 853
 854         ochain = *chainp;
 855
 856         /*
 857          * Since ochain is either disconnected from the topology or represents
 858          * a hardlink terminus which is always a parent of or equal to dip,
 859          * we should be able to safely lock dip->chain for our setup.
 860          */
 861         parent = hammer2_chain_lookup_init(dip->chain, 0);
 862
 863         lhc = hammer2_dirhash(name, name_len);
 864
 865         /*
 866          * Locate the inode or indirect block to create the new
 867          * entry in.  At the same time check for key collisions
 868          * and iterate until we don't get one.
 869          */
 870         error = 0;
 871         while (error == 0) {
 872                 nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 873                 if (nchain == NULL)
 874                         break;
 875                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 876                         error = ENOSPC;
 877                 hammer2_chain_unlock(nchain);
 878                 nchain = NULL;
 879                 ++lhc;
 880         }
 881
 882         if (error == 0) {
 883                 if (hlink) {
 884                         /*
 885                          * Hardlink pointer needed, create totally fresh
 886                          * directory entry.
 887                          */
 888                         KKASSERT(nchain == NULL);
 889                         error = hammer2_chain_create(trans, &parent, &nchain,
 890                                                      lhc, 0,
 891                                                      HAMMER2_BREF_TYPE_INODE,
 892                                                      HAMMER2_INODE_BYTES);
 893                         hammer2_chain_refactor(&ochain);
 894                 } else {
 895                         /*
 896                          * Reconnect the original chain and rename.  Use
 897                          * chain_duplicate().  The caller will likely delete
 898                          * or has already deleted the original chain in
 899                          * this case.
 900                          *
 901                          * NOTE: chain_duplicate() generates a new chain
 902                          *       with CHAIN_DELETED cleared (ochain typically
 903                          *       has it set from the file unlink).
 904                          */
 905                         nchain = ochain;
 906                         ochain = NULL;
 907                         hammer2_chain_duplicate(trans, NULL, -1, &nchain, NULL);
 908                         error = hammer2_chain_create(trans, &parent, &nchain,
 909                                                      lhc, 0,
 910                                                      HAMMER2_BREF_TYPE_INODE,
 911                                                      HAMMER2_INODE_BYTES);
 912                 }
 913         }
 914
 915         /*
 916          * Unlock stuff.
 917          */
 918         KKASSERT(error != EAGAIN);
 919         hammer2_chain_lookup_done(parent);
 920         parent = NULL;
 921
 922         /*
 923          * nchain should be NULL on error, leave ochain (== *chainp) alone.
 924          */
 925         if (error) {
 926                 KKASSERT(nchain == NULL);
 927                 return (error);
 928         }
 929
 930         /*
 931          * Directory entries are inodes so if the name has changed we have
 932          * to update the inode.
 933          *
 934          * When creating an OBJTYPE_HARDLINK entry remember to unlock the
 935          * chain, the caller will access the hardlink via the actual hardlink
 936          * target file and not the hardlink pointer entry, so we must still
 937          * return ochain.
 938          */
 939         if (hlink && hammer2_hardlink_enable >= 0) {
 940                 /*
 941                  * Create the HARDLINK pointer.  oip represents the hardlink
 942                  * target in this situation.
 943                  *
 944                  * We will return ochain (the hardlink target).
 945                  */
 946                 hammer2_chain_modify(trans, &nchain,
 947                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 948                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 949                 ipdata = &nchain->data->ipdata;
 950                 bcopy(name, ipdata->filename, name_len);
 951                 ipdata->name_key = lhc;
 952                 ipdata->name_len = name_len;
 953                 ipdata->target_type = ochain->data->ipdata.type;
 954                 ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
 955                 ipdata->inum = ochain->data->ipdata.inum;
 956                 ipdata->nlinks = 1;
 957                 hammer2_chain_unlock(nchain);
 958                 nchain = ochain;
 959                 ochain = NULL;
 960         } else if (hlink && hammer2_hardlink_enable < 0) {
 961                 /*
 962                  * Create a snapshot (hardlink fake mode for debugging).
 963                  * (ochain already flushed above so we can just copy the
 964                  * bref XXX).
 965                  *
 966                  * Since this is a snapshot we return nchain in the fake
 967                  * hardlink case.
 968                  */
 969                 hammer2_chain_modify(trans, &nchain,
 970                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 971                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 972                 ipdata = &nchain->data->ipdata;
 973                 *ipdata = ochain->data->ipdata;
 974                 bcopy(name, ipdata->filename, name_len);
 975                 ipdata->name_key = lhc;
 976                 ipdata->name_len = name_len;
 977                 kprintf("created fake hardlink %*.*s\n",
 978                         (int)name_len, (int)name_len, name);
 979         } else {
 980                 /*
 981                  * nchain is a duplicate of ochain at the new location.
 982                  * We must fixup the name stored in oip.  The bref key
 983                  * has already been set up.
 984                  */
 985                 hammer2_chain_modify(trans, &nchain,
 986                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 987                 ipdata = &nchain->data->ipdata;
 988
 989                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 990                 bcopy(name, ipdata->filename, name_len);
 991                 ipdata->name_key = lhc;
 992                 ipdata->name_len = name_len;
 993                 ipdata->nlinks = 1;
 994         }
 995
 996         /*
 997          * We are replacing ochain with nchain, unlock ochain.  In the
 998          * case where ochain is left unchanged the code above sets
 999          * nchain to ochain and ochain to NULL, resulting in a NOP here.
1000          */
1001         if (ochain)
1002                 hammer2_chain_unlock(ochain);
1003         *chainp = nchain;
1004
1005         return (0);
1006 }
1007
1008 /*
1009  * Repoint ip->chain to nchain.  Caller must hold the inode exclusively
1010  * locked.
1011  *
1012  * ip->chain is set to nchain.  The prior chain in ip->chain is dropped
1013  * and nchain is ref'd.
1014  */
1015 void
1016 hammer2_inode_repoint(hammer2_inode_t *ip, hammer2_inode_t *pip,
1017                       hammer2_chain_t *nchain)
1018 {
1019         hammer2_chain_t *ochain;
1020         hammer2_inode_t *opip;
1021
1022         /*
1023          * Repoint ip->chain if requested.
1024          */
1025         ochain = ip->chain;
1026         ip->chain = nchain;
1027         if (nchain)
1028                 hammer2_chain_ref(nchain);
1029         if (ochain)
1030                 hammer2_chain_drop(ochain);
1031
1032         /*
1033          * Repoint ip->pip if requested (non-NULL pip).
1034          */
1035         if (pip && ip->pip != pip) {
1036                 opip = ip->pip;
1037                 hammer2_inode_ref(pip);
1038                 ip->pip = pip;
1039                 if (opip)
1040                         hammer2_inode_drop(opip);
1041         }
1042 }
1043
1044 /*
1045  * Unlink the file from the specified directory inode.  The directory inode
1046  * does not need to be locked.
1047  *
1048  * isdir determines whether a directory/non-directory check should be made.
1049  * No check is made if isdir is set to -1.
1050  *
1051  * NOTE!  This function does not prevent the underlying file from still
1052  *        being used if it has other refs (such as from an inode, or if it's
1053  *        chain is manually held).  However, the caller is responsible for
1054  *        fixing up ip->chain if e.g. a rename occurs (see chain_duplicate()).
1055  */
1056 int
1057 hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip,
1058                     const uint8_t *name, size_t name_len,
1059                     int isdir, int *hlinkp)
1060 {
1061         hammer2_inode_data_t *ipdata;
1062         hammer2_mount_t *hmp;
1063         hammer2_chain_t *parent;
1064         hammer2_chain_t *ochain;
1065         hammer2_chain_t *chain;
1066         hammer2_chain_t *dparent;
1067         hammer2_chain_t *dchain;
1068         hammer2_key_t lhc;
1069         int error;
1070         uint8_t type;
1071
1072         error = 0;
1073         ochain = NULL;
1074         hmp = dip->hmp;
1075         lhc = hammer2_dirhash(name, name_len);
1076
1077         /*
1078          * Search for the filename in the directory
1079          */
1080         if (hlinkp)
1081                 *hlinkp = 0;
1082         parent = hammer2_inode_lock_ex(dip);
1083         chain = hammer2_chain_lookup(&parent,
1084                                      lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1085                                      0);
1086         while (chain) {
1087                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1088                     name_len == chain->data->ipdata.name_len &&
1089                     bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
1090                         break;
1091                 }
1092                 chain = hammer2_chain_next(&parent, chain,
1093                                            lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1094                                            0);
1095         }
1096         hammer2_inode_unlock_ex(dip, NULL);     /* retain parent */
1097
1098         /*
1099          * Not found or wrong type (isdir < 0 disables the type check).
1100          * If a hardlink pointer, type checks use the hardlink target.
1101          */
1102         if (chain == NULL) {
1103                 error = ENOENT;
1104                 goto done;
1105         }
1106         if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) {
1107                 if (hlinkp)
1108                         *hlinkp = 1;
1109                 type = chain->data->ipdata.target_type;
1110         }
1111
1112         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
1113                 error = ENOTDIR;
1114                 goto done;
1115         }
1116         if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) {
1117                 error = EISDIR;
1118                 goto done;
1119         }
1120
1121         /*
1122          * Hardlink must be resolved.  We can't hold parent locked while we
1123          * do this or we could deadlock.
1124          *
1125          * On success chain will be adjusted to point at the hardlink target
1126          * and ochain will point to the hardlink pointer in the original
1127          * directory.  Otherwise chain remains pointing to the original.
1128          */
1129         if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
1130                 hammer2_chain_unlock(parent);
1131                 parent = NULL;
1132                 error = hammer2_hardlink_find(dip, &chain, &ochain);
1133         }
1134
1135         /*
1136          * If this is a directory the directory must be empty.  However, if
1137          * isdir < 0 we are doing a rename and the directory does not have
1138          * to be empty, and if isdir > 1 we are deleting a PFS/snapshot
1139          * and the directory does not have to be empty.
1140          *
1141          * NOTE: We check the full key range here which covers both visible
1142          *       and invisible entries.  Theoretically there should be no
1143          *       invisible (hardlink target) entries if there are no visible
1144          *       entries.
1145          */
1146         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
1147                 dparent = hammer2_chain_lookup_init(chain, 0);
1148                 dchain = hammer2_chain_lookup(&dparent,
1149                                               0, (hammer2_key_t)-1,
1150                                               HAMMER2_LOOKUP_NODATA);
1151                 if (dchain) {
1152                         hammer2_chain_unlock(dchain);
1153                         hammer2_chain_lookup_done(dparent);
1154                         error = ENOTEMPTY;
1155                         goto done;
1156                 }
1157                 hammer2_chain_lookup_done(dparent);
1158                 dparent = NULL;
1159                 /* dchain NULL */
1160         }
1161
1162         /*
1163          * Ok, we can now unlink the chain.  We always decrement nlinks even
1164          * if the entry can be deleted in case someone has the file open and
1165          * does an fstat().
1166          *
1167          * The chain itself will no longer be in the on-media topology but
1168          * can still be flushed to the media (e.g. if an open descriptor
1169          * remains).  When the last vnode/ip ref goes away the chain will
1170          * be marked unmodified, avoiding any further (now unnecesary) I/O.
1171          *
1172          * A non-NULL ochain indicates a hardlink.
1173          */
1174         if (ochain) {
1175                 /*
1176                  * Delete the original hardlink pointer.
1177                  *
1178                  * NOTE: parent from above is NULL when ochain != NULL
1179                  *       so we can reuse it.
1180                  */
1181                 hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
1182                 hammer2_chain_delete(trans, ochain);
1183                 hammer2_chain_unlock(ochain);
1184
1185                 /*
1186                  * Then decrement nlinks on hardlink target, deleting
1187                  * the target when nlinks drops to 0.
1188                  */
1189                 hammer2_chain_modify(trans, &chain, 0);
1190                 --chain->data->ipdata.nlinks;
1191                 if (chain->data->ipdata.nlinks == 0)
1192                         hammer2_chain_delete(trans, chain);
1193         } else {
1194                 /*
1195                  * Otherwise this was not a hardlink and we can just
1196                  * remove the entry and decrement nlinks.
1197                  *
1198                  * NOTE: *_get() integrates chain's lock into the inode lock.
1199                  */
1200                 hammer2_chain_modify(trans, &chain, 0);
1201                 ipdata = &chain->data->ipdata;
1202                 --ipdata->nlinks;
1203                 hammer2_chain_delete(trans, chain);
1204         }
1205
1206         error = 0;
1207 done:
1208         if (chain)
1209                 hammer2_chain_unlock(chain);
1210         if (parent)
1211                 hammer2_chain_lookup_done(parent);
1212         if (ochain)
1213                 hammer2_chain_drop(ochain);
1214
1215         return error;
1216 }
1217
1218 /*
1219  * Calculate the allocation size for the file fragment straddling EOF
1220  */
1221 int
1222 hammer2_inode_calc_alloc(hammer2_key_t filesize)
1223 {
1224         int frag = (int)filesize & HAMMER2_PBUFMASK;
1225         int radix;
1226
1227         if (frag == 0)
1228                 return(0);
1229         for (radix = HAMMER2_MINALLOCRADIX; frag > (1 << radix); ++radix)
1230                 ;
1231         return (radix);
1232 }
1233
1234 /*
1235  * Given an exclusively locked inode we consolidate its chain for hardlink
1236  * creation, adding (nlinks) to the file's link count and potentially
1237  * relocating the inode to a directory common to ip->pip and tdip.
1238  *
1239  * Replaces (*chainp) if consolidation occurred, unlocking the old chain
1240  * and returning a new locked chain.
1241  *
1242  * NOTE!  This function will also replace ip->chain.
1243  */
1244 int
1245 hammer2_hardlink_consolidate(hammer2_trans_t *trans, hammer2_inode_t *ip,
1246                              hammer2_chain_t **chainp,
1247                              hammer2_inode_t *tdip, int nlinks)
1248 {
1249         hammer2_inode_data_t *ipdata;
1250         hammer2_mount_t *hmp;
1251         hammer2_inode_t *fdip;
1252         hammer2_inode_t *cdip;
1253         hammer2_chain_t *chain;
1254         hammer2_chain_t *nchain;
1255         int error;
1256
1257         hmp = tdip->hmp;
1258
1259         chain = *chainp;
1260         if (nlinks == 0 &&                      /* no hardlink needed */
1261             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE)) {
1262                 return (0);
1263         }
1264         if (hammer2_hardlink_enable < 0) {      /* fake hardlinks */
1265                 return (0);
1266         }
1267
1268         if (hammer2_hardlink_enable == 0) {     /* disallow hardlinks */
1269                 hammer2_chain_unlock(chain);
1270                 *chainp = NULL;
1271                 return (ENOTSUP);
1272         }
1273
1274         /*
1275          * cdip will be returned with a ref, but not locked.
1276          */
1277         fdip = ip->pip;
1278         cdip = hammer2_inode_common_parent(fdip, tdip);
1279
1280         /*
1281          * If no change in the hardlink's target directory is required and
1282          * this is already a hardlink target, all we need to do is adjust
1283          * the link count.
1284          *
1285          * XXX The common parent is a big wiggly due to duplication from
1286          *     renames.  Compare the core (RBTREE) pointer instead of the
1287          *     ip's.
1288          */
1289         if (cdip == fdip &&
1290             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) == 0) {
1291                 if (nlinks) {
1292                         hammer2_chain_modify(trans, &chain, 0);
1293                         chain->data->ipdata.nlinks += nlinks;
1294                 }
1295                 error = 0;
1296                 goto done;
1297         }
1298
1299         /*
1300          * We either have to move an existing hardlink target or we have
1301          * to create a fresh hardlink target.
1302          *
1303          * Hardlink targets are hidden inodes in a parent directory common
1304          * to all directory entries referencing the hardlink.
1305          */
1306         nchain = hammer2_hardlink_shiftup(trans, &chain, cdip, &error);
1307
1308         if (error == 0) {
1309                 /*
1310                  * Bump nlinks on duplicated hidden inode, repoint
1311                  * ip->chain.
1312                  */
1313                 hammer2_chain_modify(trans, &nchain, 0);
1314                 nchain->data->ipdata.nlinks += nlinks;
1315                 hammer2_inode_repoint(ip, cdip, nchain);
1316
1317                 /*
1318                  * If the old chain is not a hardlink target then replace
1319                  * it with a OBJTYPE_HARDLINK pointer.
1320                  *
1321                  * If the old chain IS a hardlink target then delete it.
1322                  */
1323                 if (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) {
1324                         /*
1325                          * Replace original non-hardlink that's been dup'd
1326                          * with a special hardlink directory entry.  We must
1327                          * set the DIRECTDATA flag to prevent sub-chains
1328                          * from trying to synchronize to the inode if the
1329                          * file is extended afterwords.
1330                          */
1331                         hammer2_chain_modify(trans, &chain, 0);
1332                         ipdata = &chain->data->ipdata;
1333                         ipdata->target_type = ipdata->type;
1334                         ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
1335                         ipdata->uflags = 0;
1336                         ipdata->rmajor = 0;
1337                         ipdata->rminor = 0;
1338                         ipdata->ctime = 0;
1339                         ipdata->mtime = 0;
1340                         ipdata->atime = 0;
1341                         ipdata->btime = 0;
1342                         bzero(&ipdata->uid, sizeof(ipdata->uid));
1343                         bzero(&ipdata->gid, sizeof(ipdata->gid));
1344                         ipdata->op_flags = HAMMER2_OPFLAG_DIRECTDATA;
1345                         ipdata->cap_flags = 0;
1346                         ipdata->mode = 0;
1347                         ipdata->size = 0;
1348                         ipdata->nlinks = 1;
1349                         ipdata->iparent = 0;    /* XXX */
1350                         ipdata->pfs_type = 0;
1351                         ipdata->pfs_inum = 0;
1352                         bzero(&ipdata->pfs_clid, sizeof(ipdata->pfs_clid));
1353                         bzero(&ipdata->pfs_fsid, sizeof(ipdata->pfs_fsid));
1354                         ipdata->data_quota = 0;
1355                         ipdata->data_count = 0;
1356                         ipdata->inode_quota = 0;
1357                         ipdata->inode_count = 0;
1358                         ipdata->attr_tid = 0;
1359                         ipdata->dirent_tid = 0;
1360                         bzero(&ipdata->u, sizeof(ipdata->u));
1361                         /* XXX transaction ids */
1362                 } else {
1363                         kprintf("DELETE INVISIBLE %p\n", chain);
1364                         hammer2_chain_delete(trans, chain);
1365                 }
1366
1367                 /*
1368                  * Return the new chain.
1369                  */
1370                 hammer2_chain_unlock(chain);
1371                 chain = nchain;
1372         } else {
1373                 /*
1374                  * Return an error
1375                  */
1376                 hammer2_chain_unlock(chain);
1377                 chain = NULL;
1378         }
1379
1380         /*
1381          * Cleanup, chain/nchain already dealt with.
1382          */
1383 done:
1384         *chainp = chain;
1385         hammer2_inode_drop(cdip);
1386
1387         return (error);
1388 }
1389
1390 /*
1391  * If (*ochainp) is non-NULL it points to the forward OBJTYPE_HARDLINK
1392  * inode while (*chainp) points to the resolved (hidden hardlink
1393  * target) inode.  In this situation when nlinks is 1 we wish to
1394  * deconsolidate the hardlink, moving it back to the directory that now
1395  * represents the only remaining link.
1396  */
1397 int
1398 hammer2_hardlink_deconsolidate(hammer2_trans_t *trans,
1399                                hammer2_inode_t *dip,
1400                                hammer2_chain_t **chainp,
1401                                hammer2_chain_t **ochainp)
1402 {
1403         if (*ochainp == NULL)
1404                 return (0);
1405         /* XXX */
1406         return (0);
1407 }
1408
1409 /*
1410  * The caller presents a locked *chainp pointing to a HAMMER2_BREF_TYPE_INODE
1411  * with an obj_type of HAMMER2_OBJTYPE_HARDLINK.  This routine will gobble
1412  * the *chainp and return a new locked *chainp representing the file target
1413  * (the original *chainp will be unlocked).
1414  *
1415  * When a match is found the chain representing the original HARDLINK
1416  * will be returned in *ochainp with a ref, but not locked.
1417  *
1418  * When no match is found *chainp is set to NULL and EIO is returned.
1419  * (*ochainp) will still be set to the original chain with a ref but not
1420  * locked.
1421  */
1422 int
1423 hammer2_hardlink_find(hammer2_inode_t *dip, hammer2_chain_t **chainp,
1424                       hammer2_chain_t **ochainp)
1425 {
1426         hammer2_chain_t *chain = *chainp;
1427         hammer2_chain_t *parent;
1428         hammer2_inode_t *ip;
1429         hammer2_inode_t *pip;
1430         hammer2_key_t lhc;
1431
1432         pip = dip;
1433         hammer2_inode_ref(pip);         /* for loop */
1434         hammer2_chain_ref(chain);       /* for (*ochainp) */
1435         *ochainp = chain;
1436
1437         /*
1438          * Locate the hardlink.  pip is referenced and not locked,
1439          * ipp.
1440          *
1441          * chain is reused.
1442          */
1443         lhc = chain->data->ipdata.inum;
1444         hammer2_chain_unlock(chain);
1445         chain = NULL;
1446
1447         while ((ip = pip) != NULL) {
1448                 parent = hammer2_inode_lock_ex(ip);
1449                 hammer2_inode_drop(ip);                 /* loop */
1450                 KKASSERT(parent->bref.type == HAMMER2_BREF_TYPE_INODE);
1451                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
1452                 hammer2_chain_lookup_done(parent);      /* discard parent */
1453                 if (chain)
1454                         break;
1455                 pip = ip->pip;          /* safe, ip held locked */
1456                 if (pip)
1457                         hammer2_inode_ref(pip);         /* loop */
1458                 hammer2_inode_unlock_ex(ip, NULL);
1459         }
1460
1461         /*
1462          * chain is locked, ip is locked.  Unlock ip, return the locked
1463          * chain.  *ipp is already set w/a ref count and not locked.
1464          *
1465          * (parent is already unlocked).
1466          */
1467         if (ip)
1468                 hammer2_inode_unlock_ex(ip, NULL);
1469         *chainp = chain;
1470         if (chain) {
1471                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
1472                 /* already locked */
1473                 return (0);
1474         } else {
1475                 return (EIO);
1476         }
1477 }
1478
1479 /*
1480  * Find the directory common to both fdip and tdip, hold and return
1481  * its inode.
1482  */
1483 hammer2_inode_t *
1484 hammer2_inode_common_parent(hammer2_inode_t *fdip, hammer2_inode_t *tdip)
1485 {
1486         hammer2_inode_t *scan1;
1487         hammer2_inode_t *scan2;
1488
1489         /*
1490          * We used to have a depth field but it complicated matters too
1491          * much for directory renames.  So now its ugly.  Check for
1492          * simple cases before giving up and doing it the expensive way.
1493          *
1494          * XXX need a bottom-up topology stability lock
1495          */
1496         if (fdip == tdip || fdip == tdip->pip) {
1497                 hammer2_inode_ref(fdip);
1498                 return(fdip);
1499         }
1500         if (fdip->pip == tdip) {
1501                 hammer2_inode_ref(tdip);
1502                 return(tdip);
1503         }
1504
1505         /*
1506          * XXX not MPSAFE
1507          */
1508         for (scan1 = fdip; scan1->pmp == fdip->pmp; scan1 = scan1->pip) {
1509                 scan2 = tdip;
1510                 while (scan2->pmp == tdip->pmp) {
1511                         if (scan1 == scan2) {
1512                                 hammer2_inode_ref(scan1);
1513                                 return(scan1);
1514                         }
1515                         scan2 = scan2->pip;
1516                         if (scan2 == NULL)
1517                                 break;
1518                 }
1519         }
1520         panic("hammer2_inode_common_parent: no common parent %p %p\n",
1521               fdip, tdip);
1522         /* NOT REACHED */
1523         return(NULL);
1524 }