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_pfsmount_t *pmp;
 234         hammer2_inode_t *pip;
 235         u_int refs;
 236
 237         while (ip) {
 238                 refs = ip->refs;
 239                 cpu_ccfence();
 240                 if (refs == 1) {
 241                         /*
 242                          * Transition to zero, must interlock with
 243                          * the inode inumber lookup tree (if applicable).
 244                          *
 245                          * NOTE: The super-root inode has no pmp.
 246                          */
 247                         pmp = ip->pmp;
 248                         if (pmp)
 249                                 spin_lock(&pmp->inum_spin);
 250
 251                         if (atomic_cmpset_int(&ip->refs, 1, 0)) {
 252                                 KKASSERT(ip->topo_cst.count == 0);
 253                                 if (ip->flags & HAMMER2_INODE_ONRBTREE) {
 254                                         atomic_clear_int(&ip->flags,
 255                                                      HAMMER2_INODE_ONRBTREE);
 256                                         RB_REMOVE(hammer2_inode_tree,
 257                                                   &pmp->inum_tree, ip);
 258                                 }
 259                                 if (pmp)
 260                                         spin_unlock(&pmp->inum_spin);
 261
 262                                 hmp = ip->hmp;
 263                                 ip->hmp = NULL;
 264                                 pip = ip->pip;
 265                                 ip->pip = NULL;
 266                                 ip->pmp = NULL;
 267
 268                                 /*
 269                                  * Cleaning out ip->chain isn't entirely
 270                                  * trivial.
 271                                  */
 272                                 hammer2_inode_repoint(ip, NULL, NULL);
 273
 274                                 /*
 275                                  * We have to drop pip (if non-NULL) to
 276                                  * dispose of our implied reference from
 277                                  * ip->pip.  We can simply loop on it.
 278                                  */
 279                                 if (pmp) {
 280                                         KKASSERT((ip->flags &
 281                                                   HAMMER2_INODE_SROOT) == 0);
 282                                         kfree(ip, pmp->minode);
 283                                 } else {
 284                                         KKASSERT(ip->flags &
 285                                                  HAMMER2_INODE_SROOT);
 286                                         kfree(ip, hmp->mchain);
 287                                 }
 288                                 ip = pip;
 289                                 /* continue with pip (can be NULL) */
 290                         } else {
 291                                 if (pmp)
 292                                         spin_unlock(&ip->pmp->inum_spin);
 293                         }
 294                 } else {
 295                         /*
 296                          * Non zero transition
 297                          */
 298                         if (atomic_cmpset_int(&ip->refs, refs, refs - 1))
 299                                 break;
 300                 }
 301         }
 302 }
 303
 304 /*
 305  * Get the vnode associated with the given inode, allocating the vnode if
 306  * necessary.  The vnode will be returned exclusively locked.
 307  *
 308  * The caller must lock the inode (shared or exclusive).
 309  *
 310  * Great care must be taken to avoid deadlocks and vnode acquisition/reclaim
 311  * races.
 312  */
 313 struct vnode *
 314 hammer2_igetv(hammer2_inode_t *ip, int *errorp)
 315 {
 316         hammer2_inode_data_t *ipdata;
 317         hammer2_pfsmount_t *pmp;
 318         struct vnode *vp;
 319         ccms_state_t ostate;
 320
 321         pmp = ip->pmp;
 322         KKASSERT(pmp != NULL);
 323         *errorp = 0;
 324         ipdata = &ip->chain->data->ipdata;
 325
 326         for (;;) {
 327                 /*
 328                  * Attempt to reuse an existing vnode assignment.  It is
 329                  * possible to race a reclaim so the vget() may fail.  The
 330                  * inode must be unlocked during the vget() to avoid a
 331                  * deadlock against a reclaim.
 332                  */
 333                 vp = ip->vp;
 334                 if (vp) {
 335                         /*
 336                          * Inode must be unlocked during the vget() to avoid
 337                          * possible deadlocks, but leave the ip ref intact.
 338                          *
 339                          * vnode is held to prevent destruction during the
 340                          * vget().  The vget() can still fail if we lost
 341                          * a reclaim race on the vnode.
 342                          */
 343                         vhold_interlocked(vp);
 344                         ostate = hammer2_inode_lock_temp_release(ip);
 345                         if (vget(vp, LK_EXCLUSIVE)) {
 346                                 vdrop(vp);
 347                                 hammer2_inode_lock_temp_restore(ip, ostate);
 348                                 continue;
 349                         }
 350                         hammer2_inode_lock_temp_restore(ip, ostate);
 351                         vdrop(vp);
 352                         /* vp still locked and ref from vget */
 353                         if (ip->vp != vp) {
 354                                 kprintf("hammer2: igetv race %p/%p\n",
 355                                         ip->vp, vp);
 356                                 vput(vp);
 357                                 continue;
 358                         }
 359                         *errorp = 0;
 360                         break;
 361                 }
 362
 363                 /*
 364                  * No vnode exists, allocate a new vnode.  Beware of
 365                  * allocation races.  This function will return an
 366                  * exclusively locked and referenced vnode.
 367                  */
 368                 *errorp = getnewvnode(VT_HAMMER2, pmp->mp, &vp, 0, 0);
 369                 if (*errorp) {
 370                         kprintf("hammer2: igetv getnewvnode failed %d\n",
 371                                 *errorp);
 372                         vp = NULL;
 373                         break;
 374                 }
 375
 376                 /*
 377                  * Lock the inode and check for an allocation race.
 378                  */
 379                 ostate = hammer2_inode_lock_upgrade(ip);
 380                 if (ip->vp != NULL) {
 381                         vp->v_type = VBAD;
 382                         vx_put(vp);
 383                         hammer2_inode_lock_downgrade(ip, ostate);
 384                         continue;
 385                 }
 386
 387                 switch (ipdata->type) {
 388                 case HAMMER2_OBJTYPE_DIRECTORY:
 389                         vp->v_type = VDIR;
 390                         break;
 391                 case HAMMER2_OBJTYPE_REGFILE:
 392                         vp->v_type = VREG;
 393                         vinitvmio(vp, ipdata->size,
 394                                   HAMMER2_LBUFSIZE,
 395                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 396                         break;
 397                 case HAMMER2_OBJTYPE_SOFTLINK:
 398                         /*
 399                          * XXX for now we are using the generic file_read
 400                          * and file_write code so we need a buffer cache
 401                          * association.
 402                          */
 403                         vp->v_type = VLNK;
 404                         vinitvmio(vp, ipdata->size,
 405                                   HAMMER2_LBUFSIZE,
 406                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 407                         break;
 408                 /* XXX FIFO */
 409                 default:
 410                         panic("hammer2: unhandled objtype %d", ipdata->type);
 411                         break;
 412                 }
 413
 414                 if (ip == pmp->iroot)
 415                         vsetflags(vp, VROOT);
 416
 417                 vp->v_data = ip;
 418                 ip->vp = vp;
 419                 hammer2_inode_ref(ip);          /* vp association */
 420                 hammer2_inode_lock_downgrade(ip, ostate);
 421                 break;
 422         }
 423
 424         /*
 425          * Return non-NULL vp and *errorp == 0, or NULL vp and *errorp != 0.
 426          */
 427         if (hammer2_debug & 0x0002) {
 428                 kprintf("igetv vp %p refs %d aux %d\n",
 429                         vp, vp->v_sysref.refcnt, vp->v_auxrefs);
 430         }
 431         return (vp);
 432 }
 433
 434 /*
 435  * The passed-in chain must be locked and the returned inode will also be
 436  * locked.  This routine typically locates or allocates the inode, assigns
 437  * ip->chain (adding a ref to chain if necessary), and returns the inode.
 438  *
 439  * The hammer2_inode structure regulates the interface between the high level
 440  * kernel VNOPS API and the filesystem backend (the chains).
 441  *
 442  * WARNING!  This routine sucks up the chain's lock (makes it part of the
 443  *           inode lock from the point of view of the inode lock API),
 444  *           so callers need to be careful.
 445  *
 446  * WARNING!  The mount code is allowed to pass dip == NULL for iroot and
 447  *           is allowed to pass pmp == NULL and dip == NULL for sroot.
 448  */
 449 hammer2_inode_t *
 450 hammer2_inode_get(hammer2_mount_t *hmp, hammer2_pfsmount_t *pmp,
 451                   hammer2_inode_t *dip, hammer2_chain_t *chain)
 452 {
 453         hammer2_inode_t *nip;
 454
 455         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
 456
 457         /*
 458          * Interlocked lookup/ref of the inode.  This code is only needed
 459          * when looking up inodes with nlinks != 0 (TODO: optimize out
 460          * otherwise and test for duplicates).
 461          */
 462 again:
 463         for (;;) {
 464                 nip = hammer2_inode_lookup(pmp, chain->data->ipdata.inum);
 465                 if (nip == NULL)
 466                         break;
 467                 ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 468                 if ((nip->flags & HAMMER2_INODE_ONRBTREE) == 0) { /* race */
 469                         ccms_thread_unlock(&nip->topo_cst);
 470                         hammer2_inode_drop(nip);
 471                         continue;
 472                 }
 473                 if (nip->chain != chain)
 474                         hammer2_inode_repoint(nip, NULL, chain);
 475
 476                 /*
 477                  * Consolidated nip/nip->chain is locked (chain locked
 478                  * by caller).
 479                  */
 480                 return nip;
 481         }
 482
 483         /*
 484          * We couldn't find the inode number, create a new inode.
 485          */
 486         if (pmp) {
 487                 nip = kmalloc(sizeof(*nip), pmp->minode, M_WAITOK | M_ZERO);
 488         } else {
 489                 nip = kmalloc(sizeof(*nip), hmp->mchain, M_WAITOK | M_ZERO);
 490                 nip->flags = HAMMER2_INODE_SROOT;
 491         }
 492         nip->inum = chain->data->ipdata.inum;
 493         hammer2_inode_repoint(nip, NULL, chain);
 494         nip->pip = dip;                         /* can be NULL */
 495         if (dip)
 496                 hammer2_inode_ref(dip); /* ref dip for nip->pip */
 497
 498         nip->pmp = pmp;
 499         nip->hmp = hmp;
 500
 501         /*
 502          * ref and lock on nip gives it state compatible to after a
 503          * hammer2_inode_lock_ex() call.
 504          */
 505         nip->refs = 1;
 506         ccms_cst_init(&nip->topo_cst, &nip->chain);
 507         ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 508         /* combination of thread lock and chain lock == inode lock */
 509
 510         /*
 511          * Attempt to add the inode.  If it fails we raced another inode
 512          * get.  Undo all the work and try again.
 513          */
 514         if (pmp) {
 515                 spin_lock(&pmp->inum_spin);
 516                 if (RB_INSERT(hammer2_inode_tree, &pmp->inum_tree, nip)) {
 517                         spin_unlock(&pmp->inum_spin);
 518                         ccms_thread_unlock(&nip->topo_cst);
 519                         hammer2_inode_drop(nip);
 520                         goto again;
 521                 }
 522                 atomic_set_int(&nip->flags, HAMMER2_INODE_ONRBTREE);
 523                 spin_unlock(&pmp->inum_spin);
 524         }
 525
 526         return (nip);
 527 }
 528
 529 /*
 530  * Create a new inode in the specified directory using the vattr to
 531  * figure out the type of inode.
 532  *
 533  * If no error occurs the new inode with its chain locked is returned in
 534  * *nipp, otherwise an error is returned and *nipp is set to NULL.
 535  *
 536  * If vap and/or cred are NULL the related fields are not set and the
 537  * inode type defaults to a directory.  This is used when creating PFSs
 538  * under the super-root, so the inode number is set to 1 in this case.
 539  *
 540  * dip is not locked on entry.
 541  */
 542 hammer2_inode_t *
 543 hammer2_inode_create(hammer2_trans_t *trans, hammer2_inode_t *dip,
 544                      struct vattr *vap, struct ucred *cred,
 545                      const uint8_t *name, size_t name_len,
 546                      hammer2_chain_t **chainp, int *errorp)
 547 {
 548         hammer2_inode_data_t *dipdata;
 549         hammer2_inode_data_t *nipdata;
 550         hammer2_mount_t *hmp;
 551         hammer2_chain_t *chain;
 552         hammer2_chain_t *parent;
 553         hammer2_inode_t *nip;
 554         hammer2_key_t lhc;
 555         int error;
 556         uid_t xuid;
 557         uuid_t dip_uid;
 558         uuid_t dip_gid;
 559         uint32_t dip_mode;
 560
 561         hmp = dip->hmp;
 562         lhc = hammer2_dirhash(name, name_len);
 563         *errorp = 0;
 564
 565         /*
 566          * Locate the inode or indirect block to create the new
 567          * entry in.  At the same time check for key collisions
 568          * and iterate until we don't get one.
 569          *
 570          * NOTE: hidden inodes do not have iterators.
 571          */
 572 retry:
 573         parent = hammer2_inode_lock_ex(dip);
 574         dipdata = &dip->chain->data->ipdata;
 575         dip_uid = dipdata->uid;
 576         dip_gid = dipdata->gid;
 577         dip_mode = dipdata->mode;
 578
 579         error = 0;
 580         while (error == 0) {
 581                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 582                 if (chain == NULL)
 583                         break;
 584                 if ((lhc & HAMMER2_DIRHASH_VISIBLE) == 0)
 585                         error = ENOSPC;
 586                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 587                         error = ENOSPC;
 588                 hammer2_chain_unlock(chain);
 589                 chain = NULL;
 590                 ++lhc;
 591         }
 592         if (error == 0) {
 593                 error = hammer2_chain_create(trans, &parent, &chain,
 594                                              lhc, 0,
 595                                              HAMMER2_BREF_TYPE_INODE,
 596                                              HAMMER2_INODE_BYTES);
 597         }
 598
 599         /*
 600          * Cleanup and handle retries.
 601          */
 602         if (error == EAGAIN) {
 603                 hammer2_chain_ref(parent);
 604                 hammer2_inode_unlock_ex(dip, parent);
 605                 hammer2_chain_wait(parent);
 606                 hammer2_chain_drop(parent);
 607                 goto retry;
 608         }
 609         hammer2_inode_unlock_ex(dip, parent);
 610
 611         if (error) {
 612                 KKASSERT(chain == NULL);
 613                 *errorp = error;
 614                 return (NULL);
 615         }
 616
 617         /*
 618          * Set up the new inode.
 619          *
 620          * NOTE: *_get() integrates chain's lock into the inode lock.
 621          *
 622          * NOTE: Only one new inode can currently be created per
 623          *       transaction.  If the need arises we can adjust
 624          *       hammer2_trans_init() to allow more.
 625          */
 626         chain->data->ipdata.inum = trans->sync_tid;
 627         nip = hammer2_inode_get(dip->hmp, dip->pmp, dip, chain);
 628         nipdata = &chain->data->ipdata;
 629
 630         if (vap) {
 631                 KKASSERT(trans->inodes_created == 0);
 632                 nipdata->type = hammer2_get_obj_type(vap->va_type);
 633                 nipdata->inum = trans->sync_tid;
 634                 ++trans->inodes_created;
 635         } else {
 636                 nipdata->type = HAMMER2_OBJTYPE_DIRECTORY;
 637                 nipdata->inum = 1;
 638         }
 639         nipdata->version = HAMMER2_INODE_VERSION_ONE;
 640         hammer2_update_time(&nipdata->ctime);
 641         nipdata->mtime = nipdata->ctime;
 642         if (vap)
 643                 nipdata->mode = vap->va_mode;
 644         nipdata->nlinks = 1;
 645         if (vap) {
 646                 if (dip) {
 647                         xuid = hammer2_to_unix_xid(&dip_uid);
 648                         xuid = vop_helper_create_uid(dip->pmp->mp,
 649                                                      dip_mode,
 650                                                      xuid,
 651                                                      cred,
 652                                                      &vap->va_mode);
 653                 } else {
 654                         xuid = 0;
 655                 }
 656                 if (vap->va_vaflags & VA_UID_UUID_VALID)
 657                         nipdata->uid = vap->va_uid_uuid;
 658                 else if (vap->va_uid != (uid_t)VNOVAL)
 659                         hammer2_guid_to_uuid(&nipdata->uid, vap->va_uid);
 660                 else
 661                         hammer2_guid_to_uuid(&nipdata->uid, xuid);
 662
 663                 if (vap->va_vaflags & VA_GID_UUID_VALID)
 664                         nipdata->gid = vap->va_gid_uuid;
 665                 else if (vap->va_gid != (gid_t)VNOVAL)
 666                         hammer2_guid_to_uuid(&nipdata->gid, vap->va_gid);
 667                 else if (dip)
 668                         nipdata->gid = dip_gid;
 669         }
 670
 671         /*
 672          * Regular files and softlinks allow a small amount of data to be
 673          * directly embedded in the inode.  This flag will be cleared if
 674          * the size is extended past the embedded limit.
 675          */
 676         if (nipdata->type == HAMMER2_OBJTYPE_REGFILE ||
 677             nipdata->type == HAMMER2_OBJTYPE_SOFTLINK) {
 678                 nipdata->op_flags |= HAMMER2_OPFLAG_DIRECTDATA;
 679         }
 680
 681         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 682         bcopy(name, nipdata->filename, name_len);
 683         nipdata->name_key = lhc;
 684         nipdata->name_len = name_len;
 685         *chainp = chain;
 686
 687         return (nip);
 688 }
 689
 690 /*
 691  * chain may have been moved around by the create.
 692  */
 693 static
 694 void
 695 hammer2_chain_refactor(hammer2_chain_t **chainp)
 696 {
 697         hammer2_chain_t *chain = *chainp;
 698         hammer2_chain_core_t *core;
 699
 700         core = chain->core;
 701         spin_lock(&core->cst.spin);
 702         while (hammer2_chain_refactor_test(chain, 1)) {
 703                 chain = chain->next_parent;
 704                 while (hammer2_chain_refactor_test(chain, 1))
 705                         chain = chain->next_parent;
 706                 hammer2_chain_ref(chain);
 707                 spin_unlock(&core->cst.spin);
 708
 709                 hammer2_chain_unlock(*chainp);
 710                 hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS |
 711                                           HAMMER2_RESOLVE_NOREF); /* eat ref */
 712                 *chainp = chain;
 713                 spin_lock(&core->cst.spin);
 714         }
 715         spin_unlock(&core->cst.spin);
 716 }
 717
 718 /*
 719  * ochain represents the target file inode.  We need to move it to the
 720  * specified common parent directory (dip) and rename it to a special
 721  * invisible "0xINODENUMBER" filename.
 722  *
 723  * We use chain_duplicate and duplicate ochain at the new location,
 724  * renaming it appropriately.  We create a temporary chain and
 725  * then delete it to placemark where the duplicate will go.  Both of
 726  * these use the inode number for (lhc) (the key), generating the
 727  * invisible filename.
 728  */
 729 static
 730 hammer2_chain_t *
 731 hammer2_hardlink_shiftup(hammer2_trans_t *trans, hammer2_chain_t **ochainp,
 732                         hammer2_inode_t *dip, int *errorp)
 733 {
 734         hammer2_inode_data_t *nipdata;
 735         hammer2_mount_t *hmp;
 736         hammer2_chain_t *parent;
 737         hammer2_chain_t *ochain;
 738         hammer2_chain_t *nchain;
 739         hammer2_chain_t *tmp;
 740         hammer2_key_t lhc;
 741         hammer2_blockref_t bref;
 742
 743         ochain = *ochainp;
 744         *errorp = 0;
 745         hmp = dip->hmp;
 746         lhc = ochain->data->ipdata.inum;
 747         KKASSERT((lhc & HAMMER2_DIRHASH_VISIBLE) == 0);
 748
 749         /*
 750          * Locate the inode or indirect block to create the new
 751          * entry in.  lhc represents the inode number so there is
 752          * no collision iteration.
 753          *
 754          * There should be no key collisions with invisible inode keys.
 755          */
 756 retry:
 757         parent = hammer2_chain_lookup_init(dip->chain, 0);
 758         nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 759         if (nchain) {
 760                 kprintf("X3 chain %p parent %p dip %p dip->chain %p\n",
 761                         nchain, parent, dip, dip->chain);
 762                 hammer2_chain_unlock(nchain);
 763                 nchain = NULL;
 764                 *errorp = ENOSPC;
 765 #if 1
 766                 Debugger("X3");
 767 #endif
 768         }
 769
 770         /*
 771          * Create entry in common parent directory using the seek position
 772          * calculated above.
 773          */
 774         if (*errorp == 0) {
 775                 KKASSERT(nchain == NULL);
 776                 *errorp = hammer2_chain_create(trans, &parent, &nchain,
 777                                                lhc, 0,
 778                                                HAMMER2_BREF_TYPE_INODE,/* n/a */
 779                                                HAMMER2_INODE_BYTES);   /* n/a */
 780                 hammer2_chain_refactor(&ochain);
 781                 *ochainp = ochain;
 782         }
 783
 784         /*
 785          * Cleanup and handle retries.
 786          */
 787         if (*errorp == EAGAIN) {
 788                 hammer2_chain_ref(parent);
 789                 hammer2_chain_lookup_done(parent);
 790                 hammer2_chain_wait(parent);
 791                 hammer2_chain_drop(parent);
 792                 goto retry;
 793         }
 794
 795         /*
 796          * Handle the error case
 797          */
 798         if (*errorp) {
 799                 KKASSERT(nchain == NULL);
 800                 hammer2_chain_lookup_done(parent);
 801                 return (NULL);
 802         }
 803
 804         /*
 805          * Use chain as a placeholder for (lhc), delete it and replace
 806          * it with our duplication.
 807          *
 808          * Gain a second lock on ochain for the duplication function to
 809          * unlock, maintain the caller's original lock across the call.
 810          *
 811          * This is a bit messy.
 812          */
 813         hammer2_chain_delete(trans, nchain);
 814         hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
 815         tmp = ochain;
 816         bref = tmp->bref;
 817         bref.key = lhc;                 /* invisible dir entry key */
 818         bref.keybits = 0;
 819         hammer2_chain_duplicate(trans, parent, nchain->index, &tmp, &bref);
 820         hammer2_chain_lookup_done(parent);
 821         hammer2_chain_unlock(nchain);   /* no longer needed */
 822
 823         /*
 824          * Now set chain to our duplicate and modify it appropriately.
 825          *
 826          * Directory entries are inodes but this is a hidden hardlink
 827          * target.  The name isn't used but to ease debugging give it
 828          * a name after its inode number.
 829          */
 830         nchain = tmp;
 831         tmp = NULL;     /* safety */
 832
 833         hammer2_chain_modify(trans, &nchain, HAMMER2_MODIFY_ASSERTNOCOPY);
 834         nipdata = &nchain->data->ipdata;
 835         ksnprintf(nipdata->filename, sizeof(nipdata->filename),
 836                   "0x%016jx", (intmax_t)nipdata->inum);
 837         nipdata->name_len = strlen(nipdata->filename);
 838         nipdata->name_key = lhc;
 839
 840         return (nchain);
 841 }
 842
 843 /*
 844  * Connect the target inode represented by (*chainp) to the media topology
 845  * at (dip, name, len).
 846  *
 847  * If hlink is TRUE this function creates an OBJTYPE_HARDLINK directory
 848  * entry instead of connecting (*chainp).
 849  *
 850  * If hlink is FALSE this function uses chain_duplicate() to make a copy
 851  * if (*chainp) in the directory entry.  (*chainp) is likely to be deleted
 852  * by the caller in this case (e.g. rename).
 853  */
 854 int
 855 hammer2_inode_connect(hammer2_trans_t *trans, int hlink,
 856                       hammer2_inode_t *dip, hammer2_chain_t **chainp,
 857                       const uint8_t *name, size_t name_len)
 858 {
 859         hammer2_inode_data_t *ipdata;
 860         hammer2_mount_t *hmp;
 861         hammer2_chain_t *nchain;
 862         hammer2_chain_t *parent;
 863         hammer2_chain_t *ochain;
 864         hammer2_key_t lhc;
 865         int error;
 866
 867         hmp = dip->hmp;
 868
 869         ochain = *chainp;
 870
 871         /*
 872          * Since ochain is either disconnected from the topology or represents
 873          * a hardlink terminus which is always a parent of or equal to dip,
 874          * we should be able to safely lock dip->chain for our setup.
 875          */
 876         parent = hammer2_chain_lookup_init(dip->chain, 0);
 877
 878         lhc = hammer2_dirhash(name, name_len);
 879
 880         /*
 881          * Locate the inode or indirect block to create the new
 882          * entry in.  At the same time check for key collisions
 883          * and iterate until we don't get one.
 884          */
 885         error = 0;
 886         while (error == 0) {
 887                 nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 888                 if (nchain == NULL)
 889                         break;
 890                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 891                         error = ENOSPC;
 892                 hammer2_chain_unlock(nchain);
 893                 nchain = NULL;
 894                 ++lhc;
 895         }
 896
 897         if (error == 0) {
 898                 if (hlink) {
 899                         /*
 900                          * Hardlink pointer needed, create totally fresh
 901                          * directory entry.
 902                          */
 903                         KKASSERT(nchain == NULL);
 904                         error = hammer2_chain_create(trans, &parent, &nchain,
 905                                                      lhc, 0,
 906                                                      HAMMER2_BREF_TYPE_INODE,
 907                                                      HAMMER2_INODE_BYTES);
 908                         hammer2_chain_refactor(&ochain);
 909                 } else {
 910                         /*
 911                          * Reconnect the original chain and rename.  Use
 912                          * chain_duplicate().  The caller will likely delete
 913                          * or has already deleted the original chain in
 914                          * this case.
 915                          *
 916                          * NOTE: chain_duplicate() generates a new chain
 917                          *       with CHAIN_DELETED cleared (ochain typically
 918                          *       has it set from the file unlink).
 919                          */
 920                         nchain = ochain;
 921                         ochain = NULL;
 922                         hammer2_chain_duplicate(trans, NULL, -1, &nchain, NULL);
 923                         error = hammer2_chain_create(trans, &parent, &nchain,
 924                                                      lhc, 0,
 925                                                      HAMMER2_BREF_TYPE_INODE,
 926                                                      HAMMER2_INODE_BYTES);
 927                 }
 928         }
 929
 930         /*
 931          * Unlock stuff.
 932          */
 933         KKASSERT(error != EAGAIN);
 934         hammer2_chain_lookup_done(parent);
 935         parent = NULL;
 936
 937         /*
 938          * nchain should be NULL on error, leave ochain (== *chainp) alone.
 939          */
 940         if (error) {
 941                 KKASSERT(nchain == NULL);
 942                 return (error);
 943         }
 944
 945         /*
 946          * Directory entries are inodes so if the name has changed we have
 947          * to update the inode.
 948          *
 949          * When creating an OBJTYPE_HARDLINK entry remember to unlock the
 950          * chain, the caller will access the hardlink via the actual hardlink
 951          * target file and not the hardlink pointer entry, so we must still
 952          * return ochain.
 953          */
 954         if (hlink && hammer2_hardlink_enable >= 0) {
 955                 /*
 956                  * Create the HARDLINK pointer.  oip represents the hardlink
 957                  * target in this situation.
 958                  *
 959                  * We will return ochain (the hardlink target).
 960                  */
 961                 hammer2_chain_modify(trans, &nchain,
 962                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 963                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 964                 ipdata = &nchain->data->ipdata;
 965                 bcopy(name, ipdata->filename, name_len);
 966                 ipdata->name_key = lhc;
 967                 ipdata->name_len = name_len;
 968                 ipdata->target_type = ochain->data->ipdata.type;
 969                 ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
 970                 ipdata->inum = ochain->data->ipdata.inum;
 971                 ipdata->nlinks = 1;
 972                 hammer2_chain_unlock(nchain);
 973                 nchain = ochain;
 974                 ochain = NULL;
 975         } else if (hlink && hammer2_hardlink_enable < 0) {
 976                 /*
 977                  * Create a snapshot (hardlink fake mode for debugging).
 978                  * (ochain already flushed above so we can just copy the
 979                  * bref XXX).
 980                  *
 981                  * Since this is a snapshot we return nchain in the fake
 982                  * hardlink case.
 983                  */
 984                 hammer2_chain_modify(trans, &nchain,
 985                                      HAMMER2_MODIFY_ASSERTNOCOPY);
 986                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 987                 ipdata = &nchain->data->ipdata;
 988                 *ipdata = ochain->data->ipdata;
 989                 bcopy(name, ipdata->filename, name_len);
 990                 ipdata->name_key = lhc;
 991                 ipdata->name_len = name_len;
 992                 kprintf("created fake hardlink %*.*s\n",
 993                         (int)name_len, (int)name_len, name);
 994         } else {
 995                 /*
 996                  * nchain is a duplicate of ochain at the new location.
 997                  * We must fixup the name stored in oip.  The bref key
 998                  * has already been set up.
 999                  */
1000                 hammer2_chain_modify(trans, &nchain,
1001                                      HAMMER2_MODIFY_ASSERTNOCOPY);
1002                 ipdata = &nchain->data->ipdata;
1003
1004                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
1005                 bcopy(name, ipdata->filename, name_len);
1006                 ipdata->name_key = lhc;
1007                 ipdata->name_len = name_len;
1008                 ipdata->nlinks = 1;
1009         }
1010
1011         /*
1012          * We are replacing ochain with nchain, unlock ochain.  In the
1013          * case where ochain is left unchanged the code above sets
1014          * nchain to ochain and ochain to NULL, resulting in a NOP here.
1015          */
1016         if (ochain)
1017                 hammer2_chain_unlock(ochain);
1018         *chainp = nchain;
1019
1020         return (0);
1021 }
1022
1023 /*
1024  * Repoint ip->chain to nchain.  Caller must hold the inode exclusively
1025  * locked.
1026  *
1027  * ip->chain is set to nchain.  The prior chain in ip->chain is dropped
1028  * and nchain is ref'd.
1029  */
1030 void
1031 hammer2_inode_repoint(hammer2_inode_t *ip, hammer2_inode_t *pip,
1032                       hammer2_chain_t *nchain)
1033 {
1034         hammer2_chain_t *ochain;
1035         hammer2_inode_t *opip;
1036
1037         /*
1038          * Repoint ip->chain if requested.
1039          */
1040         ochain = ip->chain;
1041         ip->chain = nchain;
1042         if (nchain)
1043                 hammer2_chain_ref(nchain);
1044         if (ochain)
1045                 hammer2_chain_drop(ochain);
1046
1047         /*
1048          * Repoint ip->pip if requested (non-NULL pip).
1049          */
1050         if (pip && ip->pip != pip) {
1051                 opip = ip->pip;
1052                 hammer2_inode_ref(pip);
1053                 ip->pip = pip;
1054                 if (opip)
1055                         hammer2_inode_drop(opip);
1056         }
1057 }
1058
1059 /*
1060  * Unlink the file from the specified directory inode.  The directory inode
1061  * does not need to be locked.
1062  *
1063  * isdir determines whether a directory/non-directory check should be made.
1064  * No check is made if isdir is set to -1.
1065  *
1066  * NOTE!  This function does not prevent the underlying file from still
1067  *        being used if it has other refs (such as from an inode, or if it's
1068  *        chain is manually held).  However, the caller is responsible for
1069  *        fixing up ip->chain if e.g. a rename occurs (see chain_duplicate()).
1070  */
1071 int
1072 hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip,
1073                     const uint8_t *name, size_t name_len,
1074                     int isdir, int *hlinkp)
1075 {
1076         hammer2_inode_data_t *ipdata;
1077         hammer2_mount_t *hmp;
1078         hammer2_chain_t *parent;
1079         hammer2_chain_t *ochain;
1080         hammer2_chain_t *chain;
1081         hammer2_chain_t *dparent;
1082         hammer2_chain_t *dchain;
1083         hammer2_key_t lhc;
1084         int error;
1085         uint8_t type;
1086
1087         error = 0;
1088         ochain = NULL;
1089         hmp = dip->hmp;
1090         lhc = hammer2_dirhash(name, name_len);
1091
1092         /*
1093          * Search for the filename in the directory
1094          */
1095         if (hlinkp)
1096                 *hlinkp = 0;
1097         parent = hammer2_inode_lock_ex(dip);
1098         chain = hammer2_chain_lookup(&parent,
1099                                      lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1100                                      0);
1101         while (chain) {
1102                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1103                     name_len == chain->data->ipdata.name_len &&
1104                     bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
1105                         break;
1106                 }
1107                 chain = hammer2_chain_next(&parent, chain,
1108                                            lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1109                                            0);
1110         }
1111         hammer2_inode_unlock_ex(dip, NULL);     /* retain parent */
1112
1113         /*
1114          * Not found or wrong type (isdir < 0 disables the type check).
1115          * If a hardlink pointer, type checks use the hardlink target.
1116          */
1117         if (chain == NULL) {
1118                 error = ENOENT;
1119                 goto done;
1120         }
1121         if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) {
1122                 if (hlinkp)
1123                         *hlinkp = 1;
1124                 type = chain->data->ipdata.target_type;
1125         }
1126
1127         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
1128                 error = ENOTDIR;
1129                 goto done;
1130         }
1131         if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) {
1132                 error = EISDIR;
1133                 goto done;
1134         }
1135
1136         /*
1137          * Hardlink must be resolved.  We can't hold parent locked while we
1138          * do this or we could deadlock.
1139          *
1140          * On success chain will be adjusted to point at the hardlink target
1141          * and ochain will point to the hardlink pointer in the original
1142          * directory.  Otherwise chain remains pointing to the original.
1143          */
1144         if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
1145                 hammer2_chain_unlock(parent);
1146                 parent = NULL;
1147                 error = hammer2_hardlink_find(dip, &chain, &ochain);
1148         }
1149
1150         /*
1151          * If this is a directory the directory must be empty.  However, if
1152          * isdir < 0 we are doing a rename and the directory does not have
1153          * to be empty, and if isdir > 1 we are deleting a PFS/snapshot
1154          * and the directory does not have to be empty.
1155          *
1156          * NOTE: We check the full key range here which covers both visible
1157          *       and invisible entries.  Theoretically there should be no
1158          *       invisible (hardlink target) entries if there are no visible
1159          *       entries.
1160          */
1161         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
1162                 dparent = hammer2_chain_lookup_init(chain, 0);
1163                 dchain = hammer2_chain_lookup(&dparent,
1164                                               0, (hammer2_key_t)-1,
1165                                               HAMMER2_LOOKUP_NODATA);
1166                 if (dchain) {
1167                         hammer2_chain_unlock(dchain);
1168                         hammer2_chain_lookup_done(dparent);
1169                         error = ENOTEMPTY;
1170                         goto done;
1171                 }
1172                 hammer2_chain_lookup_done(dparent);
1173                 dparent = NULL;
1174                 /* dchain NULL */
1175         }
1176
1177         /*
1178          * Ok, we can now unlink the chain.  We always decrement nlinks even
1179          * if the entry can be deleted in case someone has the file open and
1180          * does an fstat().
1181          *
1182          * The chain itself will no longer be in the on-media topology but
1183          * can still be flushed to the media (e.g. if an open descriptor
1184          * remains).  When the last vnode/ip ref goes away the chain will
1185          * be marked unmodified, avoiding any further (now unnecesary) I/O.
1186          *
1187          * A non-NULL ochain indicates a hardlink.
1188          */
1189         if (ochain) {
1190                 /*
1191                  * Delete the original hardlink pointer.
1192                  *
1193                  * NOTE: parent from above is NULL when ochain != NULL
1194                  *       so we can reuse it.
1195                  */
1196                 hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
1197                 hammer2_chain_delete(trans, ochain);
1198                 hammer2_chain_unlock(ochain);
1199
1200                 /*
1201                  * Then decrement nlinks on hardlink target, deleting
1202                  * the target when nlinks drops to 0.
1203                  */
1204                 hammer2_chain_modify(trans, &chain, 0);
1205                 --chain->data->ipdata.nlinks;
1206                 if (chain->data->ipdata.nlinks == 0)
1207                         hammer2_chain_delete(trans, chain);
1208         } else {
1209                 /*
1210                  * Otherwise this was not a hardlink and we can just
1211                  * remove the entry and decrement nlinks.
1212                  *
1213                  * NOTE: *_get() integrates chain's lock into the inode lock.
1214                  */
1215                 hammer2_chain_modify(trans, &chain, 0);
1216                 ipdata = &chain->data->ipdata;
1217                 --ipdata->nlinks;
1218                 hammer2_chain_delete(trans, chain);
1219         }
1220
1221         error = 0;
1222 done:
1223         if (chain)
1224                 hammer2_chain_unlock(chain);
1225         if (parent)
1226                 hammer2_chain_lookup_done(parent);
1227         if (ochain)
1228                 hammer2_chain_drop(ochain);
1229
1230         return error;
1231 }
1232
1233 /*
1234  * Given an exclusively locked inode we consolidate its chain for hardlink
1235  * creation, adding (nlinks) to the file's link count and potentially
1236  * relocating the inode to a directory common to ip->pip and tdip.
1237  *
1238  * Replaces (*chainp) if consolidation occurred, unlocking the old chain
1239  * and returning a new locked chain.
1240  *
1241  * NOTE!  This function will also replace ip->chain.
1242  */
1243 int
1244 hammer2_hardlink_consolidate(hammer2_trans_t *trans, hammer2_inode_t *ip,
1245                              hammer2_chain_t **chainp,
1246                              hammer2_inode_t *tdip, int nlinks)
1247 {
1248         hammer2_inode_data_t *ipdata;
1249         hammer2_mount_t *hmp;
1250         hammer2_inode_t *fdip;
1251         hammer2_inode_t *cdip;
1252         hammer2_chain_t *chain;
1253         hammer2_chain_t *nchain;
1254         int error;
1255
1256         hmp = tdip->hmp;
1257
1258         chain = *chainp;
1259         if (nlinks == 0 &&                      /* no hardlink needed */
1260             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE)) {
1261                 return (0);
1262         }
1263         if (hammer2_hardlink_enable < 0) {      /* fake hardlinks */
1264                 return (0);
1265         }
1266
1267         if (hammer2_hardlink_enable == 0) {     /* disallow hardlinks */
1268                 hammer2_chain_unlock(chain);
1269                 *chainp = NULL;
1270                 return (ENOTSUP);
1271         }
1272
1273         /*
1274          * cdip will be returned with a ref, but not locked.
1275          */
1276         fdip = ip->pip;
1277         cdip = hammer2_inode_common_parent(fdip, tdip);
1278
1279         /*
1280          * If no change in the hardlink's target directory is required and
1281          * this is already a hardlink target, all we need to do is adjust
1282          * the link count.
1283          *
1284          * XXX The common parent is a big wiggly due to duplication from
1285          *     renames.  Compare the core (RBTREE) pointer instead of the
1286          *     ip's.
1287          */
1288         if (cdip == fdip &&
1289             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) == 0) {
1290                 if (nlinks) {
1291                         hammer2_chain_modify(trans, &chain, 0);
1292                         chain->data->ipdata.nlinks += nlinks;
1293                 }
1294                 error = 0;
1295                 goto done;
1296         }
1297
1298         /*
1299          * We either have to move an existing hardlink target or we have
1300          * to create a fresh hardlink target.
1301          *
1302          * Hardlink targets are hidden inodes in a parent directory common
1303          * to all directory entries referencing the hardlink.
1304          */
1305         nchain = hammer2_hardlink_shiftup(trans, &chain, cdip, &error);
1306
1307         if (error == 0) {
1308                 /*
1309                  * Bump nlinks on duplicated hidden inode, repoint
1310                  * ip->chain.
1311                  */
1312                 hammer2_chain_modify(trans, &nchain, 0);
1313                 nchain->data->ipdata.nlinks += nlinks;
1314                 hammer2_inode_repoint(ip, cdip, nchain);
1315
1316                 /*
1317                  * If the old chain is not a hardlink target then replace
1318                  * it with a OBJTYPE_HARDLINK pointer.
1319                  *
1320                  * If the old chain IS a hardlink target then delete it.
1321                  */
1322                 if (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) {
1323                         /*
1324                          * Replace original non-hardlink that's been dup'd
1325                          * with a special hardlink directory entry.  We must
1326                          * set the DIRECTDATA flag to prevent sub-chains
1327                          * from trying to synchronize to the inode if the
1328                          * file is extended afterwords.
1329                          */
1330                         hammer2_chain_modify(trans, &chain, 0);
1331                         hammer2_chain_delete_duplicate(trans, &chain,
1332                                                        HAMMER2_DELDUP_RECORE);
1333                         ipdata = &chain->data->ipdata;
1334                         ipdata->target_type = ipdata->type;
1335                         ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
1336                         ipdata->uflags = 0;
1337                         ipdata->rmajor = 0;
1338                         ipdata->rminor = 0;
1339                         ipdata->ctime = 0;
1340                         ipdata->mtime = 0;
1341                         ipdata->atime = 0;
1342                         ipdata->btime = 0;
1343                         bzero(&ipdata->uid, sizeof(ipdata->uid));
1344                         bzero(&ipdata->gid, sizeof(ipdata->gid));
1345                         ipdata->op_flags = HAMMER2_OPFLAG_DIRECTDATA;
1346                         ipdata->cap_flags = 0;
1347                         ipdata->mode = 0;
1348                         ipdata->size = 0;
1349                         ipdata->nlinks = 1;
1350                         ipdata->iparent = 0;    /* XXX */
1351                         ipdata->pfs_type = 0;
1352                         ipdata->pfs_inum = 0;
1353                         bzero(&ipdata->pfs_clid, sizeof(ipdata->pfs_clid));
1354                         bzero(&ipdata->pfs_fsid, sizeof(ipdata->pfs_fsid));
1355                         ipdata->data_quota = 0;
1356                         ipdata->data_count = 0;
1357                         ipdata->inode_quota = 0;
1358                         ipdata->inode_count = 0;
1359                         ipdata->attr_tid = 0;
1360                         ipdata->dirent_tid = 0;
1361                         bzero(&ipdata->u, sizeof(ipdata->u));
1362                         /* XXX transaction ids */
1363                 } else {
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 }