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 /*
  45  * Adding a ref to an inode is only legal if the inode already has at least
  46  * one ref.
  47  */
  48 void
  49 hammer2_inode_ref(hammer2_inode_t *ip)
  50 {
  51         atomic_add_int(&ip->refs, 1);
  52 }
  53
  54 /*
  55  * Drop an inode reference, freeing the inode when the last reference goes
  56  * away.
  57  */
  58 void
  59 hammer2_inode_drop(hammer2_inode_t *ip)
  60 {
  61         hammer2_mount_t *hmp;
  62         hammer2_inode_t *pip;
  63         hammer2_chain_t *chain;
  64         u_int refs;
  65
  66         for (;;) {
  67                 refs = ip->refs;
  68                 cpu_ccfence();
  69                 if (refs == 1) {
  70                         if (atomic_cmpset_int(&ip->refs, 1, 0)) {
  71                                 KKASSERT(ip->topo_cst.count == 0);
  72
  73                                 hmp = ip->hmp;
  74                                 ip->hmp = NULL;
  75                                 pip = ip->pip;
  76                                 ip->pip = NULL;
  77                                 chain = ip->chain;
  78                                 ip->chain = NULL;
  79                                 if (chain)
  80                                         hammer2_chain_drop(chain);
  81
  82                                 /*
  83                                  * We have to drop pip (if non-NULL) to
  84                                  * dispose of our implied reference from
  85                                  * ip->pip.  We can simply loop on it.
  86                                  */
  87                                 kfree(ip, hmp->minode);
  88                                 if (pip == NULL)
  89                                         break;
  90                                 ip = pip;
  91                                 /* continue */
  92                         }
  93                 } else {
  94                         if (atomic_cmpset_int(&ip->refs, refs, refs - 1))
  95                                 break;
  96                 }
  97         }
  98 }
  99
 100 /*
 101  * Get the vnode associated with the given inode, allocating the vnode if
 102  * necessary.  The vnode will be returned exclusively locked.
 103  *
 104  * The caller must lock the inode (shared or exclusive).
 105  *
 106  * Great care must be taken to avoid deadlocks and vnode acquisition/reclaim
 107  * races.
 108  */
 109 struct vnode *
 110 hammer2_igetv(hammer2_inode_t *ip, int *errorp)
 111 {
 112         hammer2_inode_data_t *ipdata;
 113         hammer2_pfsmount_t *pmp;
 114         struct vnode *vp;
 115         ccms_state_t ostate;
 116
 117         pmp = ip->pmp;
 118         KKASSERT(pmp != NULL);
 119         *errorp = 0;
 120         ipdata = &ip->chain->data->ipdata;
 121
 122         for (;;) {
 123                 /*
 124                  * Attempt to reuse an existing vnode assignment.  It is
 125                  * possible to race a reclaim so the vget() may fail.  The
 126                  * inode must be unlocked during the vget() to avoid a
 127                  * deadlock against a reclaim.
 128                  */
 129                 vp = ip->vp;
 130                 if (vp) {
 131                         /*
 132                          * Inode must be unlocked during the vget() to avoid
 133                          * possible deadlocks, but leave the ip ref intact.
 134                          *
 135                          * vnode is held to prevent destruction during the
 136                          * vget().  The vget() can still fail if we lost
 137                          * a reclaim race on the vnode.
 138                          */
 139                         vhold_interlocked(vp);
 140                         ostate = hammer2_inode_lock_temp_release(ip);
 141                         if (vget(vp, LK_EXCLUSIVE)) {
 142                                 vdrop(vp);
 143                                 hammer2_inode_lock_restore(ip, ostate);
 144                                 continue;
 145                         }
 146                         hammer2_inode_lock_restore(ip, ostate);
 147                         vdrop(vp);
 148                         /* vp still locked and ref from vget */
 149                         if (ip->vp != vp) {
 150                                 kprintf("hammer2: igetv race %p/%p\n",
 151                                         ip->vp, vp);
 152                                 vput(vp);
 153                                 continue;
 154                         }
 155                         *errorp = 0;
 156                         break;
 157                 }
 158
 159                 /*
 160                  * No vnode exists, allocate a new vnode.  Beware of
 161                  * allocation races.  This function will return an
 162                  * exclusively locked and referenced vnode.
 163                  */
 164                 *errorp = getnewvnode(VT_HAMMER2, pmp->mp, &vp, 0, 0);
 165                 if (*errorp) {
 166                         kprintf("hammer2: igetv getnewvnode failed %d\n",
 167                                 *errorp);
 168                         vp = NULL;
 169                         break;
 170                 }
 171
 172                 /*
 173                  * Lock the inode and check for an allocation race.
 174                  */
 175                 ostate = hammer2_inode_lock_upgrade(ip);
 176                 if (ip->vp != NULL) {
 177                         vp->v_type = VBAD;
 178                         vx_put(vp);
 179                         hammer2_inode_lock_restore(ip, ostate);
 180                         continue;
 181                 }
 182
 183                 switch (ipdata->type) {
 184                 case HAMMER2_OBJTYPE_DIRECTORY:
 185                         vp->v_type = VDIR;
 186                         break;
 187                 case HAMMER2_OBJTYPE_REGFILE:
 188                         vp->v_type = VREG;
 189                         vinitvmio(vp, ipdata->size,
 190                                   HAMMER2_LBUFSIZE,
 191                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 192                         break;
 193                 case HAMMER2_OBJTYPE_SOFTLINK:
 194                         /*
 195                          * XXX for now we are using the generic file_read
 196                          * and file_write code so we need a buffer cache
 197                          * association.
 198                          */
 199                         vp->v_type = VLNK;
 200                         vinitvmio(vp, ipdata->size,
 201                                   HAMMER2_LBUFSIZE,
 202                                   (int)ipdata->size & HAMMER2_LBUFMASK);
 203                         break;
 204                 /* XXX FIFO */
 205                 default:
 206                         panic("hammer2: unhandled objtype %d", ipdata->type);
 207                         break;
 208                 }
 209
 210                 if (ip == pmp->iroot)
 211                         vsetflags(vp, VROOT);
 212
 213                 vp->v_data = ip;
 214                 ip->vp = vp;
 215                 hammer2_inode_ref(ip);          /* vp association */
 216                 hammer2_inode_lock_restore(ip, ostate);
 217                 break;
 218         }
 219
 220         /*
 221          * Return non-NULL vp and *errorp == 0, or NULL vp and *errorp != 0.
 222          */
 223         if (hammer2_debug & 0x0002) {
 224                 kprintf("igetv vp %p refs %d aux %d\n",
 225                         vp, vp->v_sysref.refcnt, vp->v_auxrefs);
 226         }
 227         return (vp);
 228 }
 229
 230 /*
 231  * The passed-in chain must be locked and the returned inode will also be
 232  * locked.  A ref is added to both the chain and the inode.
 233  *
 234  * The hammer2_inode structure regulates the interface between the high level
 235  * kernel VNOPS API and the filesystem backend (the chains).
 236  *
 237  * NOTE!     This routine allocates the hammer2_inode structure
 238  *           unconditionally, and thus there might be several which
 239  *           are associated with the same chain.  Particularly for hardlinks
 240  *           but this can also happen temporarily for normal files and
 241  *           directories.
 242  *
 243  * WARNING!  This routine sucks up the chain's lock (makes it part of the
 244  *           inode lock from the point of view of the inode lock API),
 245  *           so callers need to be careful.
 246  *
 247  * WARNING!  The mount code is allowed to pass dip == NULL for iroot and
 248  *           is allowed to pass pmp == NULL and dip == NULL for sroot.
 249  */
 250 hammer2_inode_t *
 251 hammer2_inode_get(hammer2_mount_t *hmp, hammer2_pfsmount_t *pmp,
 252                   hammer2_inode_t *dip, hammer2_chain_t *chain)
 253 {
 254         hammer2_inode_t *nip;
 255
 256         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
 257
 258         nip = kmalloc(sizeof(*nip), hmp->minode, M_WAITOK | M_ZERO);
 259
 260         nip->chain = chain;
 261         hammer2_chain_ref(chain);               /* nip->chain */
 262         nip->pip = dip;                         /* can be NULL */
 263         if (dip)
 264                 hammer2_inode_ref(dip); /* ref dip for nip->pip */
 265
 266         nip->pmp = pmp;
 267         nip->hmp = hmp;
 268
 269         /*
 270          * ref and lock on nip gives it state compatible to after a
 271          * hammer2_inode_lock_ex() call.
 272          */
 273         nip->refs = 1;
 274         ccms_cst_init(&nip->topo_cst, &nip->chain);
 275         ccms_thread_lock(&nip->topo_cst, CCMS_STATE_EXCLUSIVE);
 276         /* combination of thread lock and chain lock == inode lock */
 277
 278         return (nip);
 279 }
 280
 281 /*
 282  * Put away an inode, unlocking it and disconnecting it from its chain.
 283  *
 284  * The inode must be exclusively locked on call and non-recursed, with
 285  * at least 2 refs (one belonging to the exclusive lock, and one additional
 286  * ref belonging to the caller).
 287  *
 288  * Upon return the inode typically has one ref remaining which the caller
 289  * drops.
 290  */
 291 void
 292 hammer2_inode_put(hammer2_inode_t *ip)
 293 {
 294         hammer2_inode_t *pip;
 295         hammer2_chain_t *chain;
 296
 297         /*
 298          * Disconnect and unlock chain
 299          */
 300         KKASSERT(ip->refs >= 2);
 301         KKASSERT(ip->topo_cst.count == -1);     /* one excl lock allowed */
 302         if ((chain = ip->chain) != NULL) {
 303                 ip->chain = NULL;
 304                 hammer2_inode_unlock_ex(ip);
 305                 hammer2_chain_unlock(chain);    /* because ip->chain now NULL */
 306                 hammer2_chain_drop(chain);      /* from *_get() */
 307         }
 308
 309         /*
 310          * Disconnect pip
 311          */
 312         if ((pip = ip->pip) != NULL) {
 313                 ip->pip = NULL;
 314                 hammer2_inode_drop(pip);
 315         }
 316 }
 317
 318 /*
 319  * Create a new inode in the specified directory using the vattr to
 320  * figure out the type of inode.
 321  *
 322  * If no error occurs the new inode with its chain locked is returned in
 323  * *nipp, otherwise an error is returned and *nipp is set to NULL.
 324  *
 325  * If vap and/or cred are NULL the related fields are not set and the
 326  * inode type defaults to a directory.  This is used when creating PFSs
 327  * under the super-root, so the inode number is set to 1 in this case.
 328  *
 329  * dip is not locked on entry.
 330  */
 331 hammer2_inode_t *
 332 hammer2_inode_create(hammer2_trans_t *trans, hammer2_inode_t *dip,
 333                      struct vattr *vap, struct ucred *cred,
 334                      const uint8_t *name, size_t name_len,
 335                      int *errorp)
 336 {
 337         hammer2_inode_data_t *dipdata;
 338         hammer2_inode_data_t *nipdata;
 339         hammer2_mount_t *hmp;
 340         hammer2_chain_t *chain;
 341         hammer2_chain_t *parent;
 342         hammer2_inode_t *nip;
 343         hammer2_key_t lhc;
 344         int error;
 345         uid_t xuid;
 346         uuid_t dip_uid;
 347         uuid_t dip_gid;
 348         uint32_t dip_mode;
 349
 350         hmp = dip->hmp;
 351         lhc = hammer2_dirhash(name, name_len);
 352         *errorp = 0;
 353
 354         /*
 355          * Locate the inode or indirect block to create the new
 356          * entry in.  At the same time check for key collisions
 357          * and iterate until we don't get one.
 358          */
 359 retry:
 360         hammer2_inode_lock_ex(dip);
 361         dipdata = &dip->chain->data->ipdata;
 362         dip_uid = dipdata->uid;
 363         dip_gid = dipdata->gid;
 364         dip_mode = dipdata->mode;
 365
 366         parent = hammer2_chain_lookup_init(dip->chain, 0);
 367         error = 0;
 368         while (error == 0) {
 369                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 370                 if (chain == NULL)
 371                         break;
 372                 if ((lhc & HAMMER2_DIRHASH_VISIBLE) == 0)
 373                         error = ENOSPC;
 374                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 375                         error = ENOSPC;
 376                 hammer2_chain_unlock(chain);
 377                 chain = NULL;
 378                 ++lhc;
 379         }
 380         if (error == 0) {
 381                 error = hammer2_chain_create(trans, parent, &chain,
 382                                              lhc, 0,
 383                                              HAMMER2_BREF_TYPE_INODE,
 384                                              HAMMER2_INODE_BYTES);
 385         }
 386
 387         /*
 388          * Cleanup and handle retries.
 389          */
 390         if (error == EAGAIN) {
 391                 hammer2_chain_ref(parent);
 392                 hammer2_chain_lookup_done(parent);
 393                 hammer2_inode_unlock_ex(dip);
 394                 hammer2_chain_wait(parent);
 395                 hammer2_chain_drop(parent);
 396                 goto retry;
 397         }
 398         hammer2_chain_lookup_done(parent);
 399         hammer2_inode_unlock_ex(dip);
 400
 401         if (error) {
 402                 KKASSERT(chain == NULL);
 403                 *errorp = error;
 404                 return (NULL);
 405         }
 406
 407         /*
 408          * Set up the new inode.
 409          *
 410          * NOTE: *_get() integrates chain's lock into the inode lock.
 411          *
 412          * NOTE: Only one new inode can currently be created per
 413          *       transaction.  If the need arises we can adjust
 414          *       hammer2_trans_init() to allow more.
 415          */
 416         nip = hammer2_inode_get(dip->hmp, dip->pmp, dip, chain);
 417         nipdata = &chain->data->ipdata;
 418
 419         if (vap) {
 420                 KKASSERT(trans->inodes_created == 0);
 421                 nipdata->type = hammer2_get_obj_type(vap->va_type);
 422                 nipdata->inum = trans->sync_tid;
 423                 ++trans->inodes_created;
 424         } else {
 425                 nipdata->type = HAMMER2_OBJTYPE_DIRECTORY;
 426                 nipdata->inum = 1;
 427         }
 428         nipdata->version = HAMMER2_INODE_VERSION_ONE;
 429         hammer2_update_time(&nipdata->ctime);
 430         nipdata->mtime = nipdata->ctime;
 431         if (vap)
 432                 nipdata->mode = vap->va_mode;
 433         nipdata->nlinks = 1;
 434         if (vap) {
 435                 if (dip) {
 436                         xuid = hammer2_to_unix_xid(&dip_uid);
 437                         xuid = vop_helper_create_uid(dip->pmp->mp,
 438                                                      dip_mode,
 439                                                      xuid,
 440                                                      cred,
 441                                                      &vap->va_mode);
 442                 } else {
 443                         xuid = 0;
 444                 }
 445                 if (vap->va_vaflags & VA_UID_UUID_VALID)
 446                         nipdata->uid = vap->va_uid_uuid;
 447                 else if (vap->va_uid != (uid_t)VNOVAL)
 448                         hammer2_guid_to_uuid(&nipdata->uid, vap->va_uid);
 449                 else
 450                         hammer2_guid_to_uuid(&nipdata->uid, xuid);
 451
 452                 if (vap->va_vaflags & VA_GID_UUID_VALID)
 453                         nipdata->gid = vap->va_gid_uuid;
 454                 else if (vap->va_gid != (gid_t)VNOVAL)
 455                         hammer2_guid_to_uuid(&nipdata->gid, vap->va_gid);
 456                 else if (dip)
 457                         nipdata->gid = dip_gid;
 458         }
 459
 460         /*
 461          * Regular files and softlinks allow a small amount of data to be
 462          * directly embedded in the inode.  This flag will be cleared if
 463          * the size is extended past the embedded limit.
 464          */
 465         if (nipdata->type == HAMMER2_OBJTYPE_REGFILE ||
 466             nipdata->type == HAMMER2_OBJTYPE_SOFTLINK) {
 467                 nipdata->op_flags |= HAMMER2_OPFLAG_DIRECTDATA;
 468         }
 469
 470         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 471         bcopy(name, nipdata->filename, name_len);
 472         nipdata->name_key = lhc;
 473         nipdata->name_len = name_len;
 474
 475         return (nip);
 476 }
 477
 478 /*
 479  * Create a duplicate of (ochain) in the specified target directory (dip).
 480  * ochain must represent an inode.  The new chain is returned locked and
 481  * referenced.
 482  */
 483 hammer2_chain_t *
 484 hammer2_inode_duplicate(hammer2_trans_t *trans, hammer2_chain_t *ochain,
 485                         hammer2_inode_t *dip, int *errorp)
 486 {
 487         hammer2_inode_data_t *nipdata;
 488         hammer2_mount_t *hmp;
 489         hammer2_chain_t *parent;
 490         hammer2_chain_t *chain;
 491         hammer2_key_t lhc;
 492
 493         *errorp = 0;
 494         hmp = dip->hmp;
 495         lhc = ochain->data->ipdata.inum;
 496         KKASSERT((lhc & HAMMER2_DIRHASH_VISIBLE) == 0);
 497
 498         /*
 499          * Locate the inode or indirect block to create the new
 500          * entry in.
 501          *
 502          * There should be no key collisions with invisible inode keys.
 503          */
 504 retry:
 505         parent = hammer2_chain_lookup_init(dip->chain, 0);
 506         chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 507         if (chain) {
 508                 hammer2_chain_unlock(chain);
 509                 chain = NULL;
 510                 *errorp = ENOSPC;
 511         }
 512
 513         /*
 514          * Create entry in common parent directory.
 515          */
 516         if (*errorp == 0) {
 517                 *errorp = hammer2_chain_create(trans, parent, &chain,
 518                                                lhc, 0,
 519                                                HAMMER2_BREF_TYPE_INODE,/* n/a */
 520                                                HAMMER2_INODE_BYTES);   /* n/a */
 521         }
 522
 523         /*
 524          * Cleanup and handle retries.
 525          */
 526         if (*errorp == EAGAIN) {
 527                 hammer2_chain_ref(parent);
 528                 hammer2_chain_lookup_done(parent);
 529                 hammer2_chain_wait(parent);
 530                 hammer2_chain_drop(parent);
 531                 goto retry;
 532         }
 533
 534         hammer2_chain_lookup_done(parent);
 535
 536         /*
 537          * Handle the error case
 538          */
 539         if (*errorp) {
 540                 KKASSERT(chain == NULL);
 541                 return (NULL);
 542         }
 543
 544         /*
 545          * XXX This is currently a horrible hack.  Well, if we wanted to
 546          *     duplicate a file, i.e. as in a snapshot, we definitely
 547          *     would have to flush it first.
 548          *
 549          *     For hardlink target generation we can theoretically move any
 550          *     active chain structures without flushing, but that gets really
 551          *     iffy for code which follows chain->parent and ip->pip links.
 552          *
 553          * XXX only works with files.  Duplicating a directory hierarchy
 554          *     requires a flush but doesn't deal with races post-flush.
 555          *     Well, it would work I guess, but you might catch some files
 556          *     mid-operation.
 557          *
 558          * We cannot leave ochain with any in-memory chains because (for a
 559          * hardlink), ochain will become a OBJTYPE_HARDLINK which is just a
 560          * pointer to the real hardlink's inum and can't have any sub-chains.
 561          * XXX might be 0-ref chains left.
 562          */
 563         hammer2_chain_flush(trans, ochain);
 564         /*KKASSERT(RB_EMPTY(&ochain.rbhead));*/
 565
 566         hammer2_chain_modify(trans, chain, 0);
 567         nipdata = &chain->data->ipdata;
 568         *nipdata = ochain->data->ipdata;
 569
 570         /*
 571          * Directory entries are inodes but this is a hidden hardlink
 572          * target.  The name isn't used but to ease debugging give it
 573          * a name after its inode number.
 574          */
 575         ksnprintf(nipdata->filename, sizeof(nipdata->filename),
 576                   "0x%016jx", (intmax_t)nipdata->inum);
 577         nipdata->name_len = strlen(nipdata->filename);
 578         nipdata->name_key = lhc;
 579
 580         return (chain);
 581 }
 582
 583 /*
 584  * Connect the target inode to the media topology at (dip, name, len).
 585  * This function creates a directory entry and replace (*chainp).
 586  *
 587  * If (*chainp) was marked DELETED then it represents a terminus inode
 588  * with no other nlinks, we can simply duplicate the chain (in-memory
 589  * chain structures cannot be moved within the in-memory topology, only
 590  * duplicated, but the duplicate uses the same bref).
 591  *
 592  * if (*chainp) is not marked DELETED then it represents a hardlink
 593  * terminus which still has a non-zero nlink count.  Instead of duplicating
 594  * it (which would be like a snapshot), we need to create a
 595  * OBJTYPE_HARDLINK directory entry which references (*chainp)'s inode
 596  * number and bump (*chainp)'s nlinks.  In this situation we return
 597  * the terminus as *chainp.
 598  *
 599  * (*chainp) is adjusted if necessary and returned locked.  If different,
 600  * the original (*chainp) is unlocked.  Note that the (*chainp) that is
 601  * returned is always the hardlink terminus (the actual inode), which
 602  * might reside in some parent directory.  It will not be the
 603  * OBJTYPE_HARDLINK pointer.
 604  *
 605  * WARNING!  This function will also replace ip->chain.  The related inode
 606  *           must be locked exclusively or would wind up racing other
 607  *           modifying operations on the same inode which then wind up
 608  *           modifying under the old chain instead of the new chain.
 609  */
 610 int
 611 hammer2_inode_connect(hammer2_trans_t *trans, hammer2_inode_t *dip,
 612                       hammer2_inode_t *ip, hammer2_chain_t **chainp,
 613                       const uint8_t *name, size_t name_len)
 614 {
 615         hammer2_inode_data_t *ipdata;
 616         hammer2_mount_t *hmp;
 617         hammer2_chain_t *nchain;
 618         hammer2_chain_t *parent;
 619         hammer2_chain_t *ochain;
 620         hammer2_key_t lhc;
 621         int error;
 622         int hlink;
 623
 624         hmp = dip->hmp;
 625
 626         ochain = *chainp;
 627
 628         /*
 629          * Since ochain is either disconnected from the topology or represents
 630          * a hardlink terminus which is always a parent of or equal to dip,
 631          * we should be able to safely lock dip->chain for our setup.
 632          */
 633         parent = hammer2_chain_lookup_init(dip->chain, 0);
 634
 635         lhc = hammer2_dirhash(name, name_len);
 636         hlink = ((ochain->flags & HAMMER2_CHAIN_DELETED) != 0);
 637         kprintf("reconnect hlink=%d name=%*.*s\n",
 638                 hlink, (int)name_len, (int)name_len, name);
 639
 640         /*
 641          * In fake mode flush oip so we can just snapshot it downbelow.
 642          * A flush is not otherwise needed as the new chain inherits
 643          * all active children of the old chain (they will share the same
 644          * chain_core).
 645          */
 646         if (hlink && hammer2_hardlink_enable < 0)
 647                 hammer2_chain_flush(trans, ochain);
 648
 649         /*
 650          * Locate the inode or indirect block to create the new
 651          * entry in.  At the same time check for key collisions
 652          * and iterate until we don't get one.
 653          */
 654         error = 0;
 655         while (error == 0) {
 656                 nchain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
 657                 if (nchain == NULL)
 658                         break;
 659                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 660                         error = ENOSPC;
 661                 hammer2_chain_unlock(nchain);
 662                 nchain = NULL;
 663                 ++lhc;
 664         }
 665
 666         /*
 667          * Passing a non-NULL chain to hammer2_chain_create() reconnects the
 668          * existing chain instead of creating a new one.  The chain's bref
 669          * will be properly updated.
 670          */
 671         if (error == 0) {
 672                 if (hlink) {
 673                         /*
 674                          * Hardlink pointer needed, create totally fresh
 675                          * directory entry.
 676                          */
 677                         KKASSERT(nchain == NULL);
 678                         error = hammer2_chain_create(trans, parent, &nchain,
 679                                                      lhc, 0,
 680                                                      HAMMER2_BREF_TYPE_INODE,
 681                                                      HAMMER2_INODE_BYTES);
 682                 } else {
 683                         /*
 684                          * Original inode reconnected, duplicate as a
 685                          * new directory entry, leave unconnected and
 686                          * then call chain_create() to connect it.
 687                          */
 688                         nchain = ochain;
 689                         ochain = NULL;
 690                         hammer2_chain_duplicate(trans, NULL, -1, &nchain);
 691                         error = hammer2_chain_create(trans, parent, &nchain,
 692                                                      lhc, 0,
 693                                                      HAMMER2_BREF_TYPE_INODE,
 694                                                      HAMMER2_INODE_BYTES);
 695                 }
 696         }
 697
 698         /*
 699          * Unlock stuff.
 700          */
 701         KKASSERT(error != EAGAIN);
 702         hammer2_chain_lookup_done(parent);
 703         parent = NULL;
 704
 705         /*
 706          * ochain still active.
 707          *
 708          * Handle the error case
 709          */
 710         if (error) {
 711                 KKASSERT(nchain == NULL);
 712                 hammer2_chain_unlock(ochain);
 713                 return (error);
 714         }
 715
 716         /*
 717          * Directory entries are inodes so if the name has changed we have
 718          * to update the inode.
 719          *
 720          * When creating an OBJTYPE_HARDLINK entry remember to unlock the
 721          * chain, the caller will access the hardlink via the actual hardlink
 722          * target file and not the hardlink pointer entry, so we must still
 723          * return ochain.
 724          */
 725         if (hlink && hammer2_hardlink_enable >= 0) {
 726                 /*
 727                  * Create the HARDLINK pointer.  oip represents the hardlink
 728                  * target in this situation.
 729                  */
 730                 hammer2_chain_modify(trans, nchain, 0);
 731                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 732                 ipdata = &nchain->data->ipdata;
 733                 bcopy(name, ipdata->filename, name_len);
 734                 ipdata->name_key = lhc;
 735                 ipdata->name_len = name_len;
 736                 ipdata->target_type = ochain->data->ipdata.type;
 737                 ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
 738                 ipdata->inum = ochain->data->ipdata.inum;
 739                 ipdata->nlinks = 1;
 740                 kprintf("created hardlink %*.*s\n",
 741                         (int)name_len, (int)name_len, name);
 742                 hammer2_chain_unlock(nchain);
 743                 nchain = ochain;
 744                 ochain = NULL;
 745         } else if (hlink && hammer2_hardlink_enable < 0) {
 746                 /*
 747                  * Create a snapshot (hardlink fake mode for debugging).
 748                  * (ochain already flushed above so we can just copy the
 749                  * bref XXX).
 750                  *
 751                  * Since this is a snapshot we return nchain in the fake
 752                  * hardlink case.
 753                  */
 754                 hammer2_chain_modify(trans, nchain, 0);
 755                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 756                 ipdata = &nchain->data->ipdata;
 757                 *ipdata = ochain->data->ipdata;
 758                 bcopy(name, ipdata->filename, name_len);
 759                 ipdata->name_key = lhc;
 760                 ipdata->name_len = name_len;
 761                 kprintf("created fake hardlink %*.*s\n",
 762                         (int)name_len, (int)name_len, name);
 763         } else {
 764                 /*
 765                  * We are reconnecting a previously DELETED node in a new
 766                  * location.  nchain is a duplication of the deleted node.
 767                  *
 768                  * We must fixup the name stored in oip.
 769                  */
 770                 hammer2_chain_modify(trans, nchain, 0);
 771                 ipdata = &nchain->data->ipdata;
 772
 773                 if (ipdata->name_len != name_len ||
 774                     bcmp(ipdata->filename, name, name_len) != 0) {
 775                         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 776                         bcopy(name, ipdata->filename, name_len);
 777                         ipdata->name_key = lhc;
 778                         ipdata->name_len = name_len;
 779                 }
 780                 ipdata->nlinks = 1;
 781         }
 782         if (ochain)
 783                 hammer2_chain_unlock(ochain);
 784         *chainp = nchain;
 785
 786         /*
 787          * Replace ip->chain if necessary.  XXX inode sub-topology replacement.
 788          */
 789         if (ip->chain != nchain) {
 790                 hammer2_chain_ref(nchain);                      /* ip->chain */
 791                 if (ip->chain)
 792                         hammer2_chain_drop(ip->chain);          /* ip->chain */
 793                 ip->chain = nchain;
 794         }
 795
 796         return (0);
 797 }
 798
 799 /*
 800  * Unlink the file from the specified directory inode.  The directory inode
 801  * does not need to be locked.  The caller should pass a non-NULL (ip)
 802  * representing the object being removed only if the related vnode is
 803  * potentially inactive (not referenced in the caller's active path),
 804  * so we can vref/vrele it to trigger the VOP_INACTIVE path and properly
 805  * recycle it.
 806  *
 807  * isdir determines whether a directory/non-directory check should be made.
 808  * No check is made if isdir is set to -1.
 809  *
 810  * NOTE!  This function does not prevent the underlying file from still
 811  *        being used if it has other refs (such as from an inode, or if it's
 812  *        chain is manually held).  However, the caller is responsible for
 813  *        fixing up ip->chain if e.g. a rename occurs (see chain_duplicate()).
 814  */
 815 int
 816 hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip,
 817                     const uint8_t *name, size_t name_len, int isdir)
 818 {
 819         hammer2_inode_data_t *ipdata;
 820         hammer2_mount_t *hmp;
 821         hammer2_chain_t *parent;
 822         hammer2_chain_t *ochain;
 823         hammer2_chain_t *chain;
 824         hammer2_chain_t *dparent;
 825         hammer2_chain_t *dchain;
 826         hammer2_key_t lhc;
 827         int error;
 828         int parent_ref;
 829         uint8_t type;
 830
 831         parent_ref = 0;
 832         error = 0;
 833         ochain = NULL;
 834         hmp = dip->hmp;
 835         lhc = hammer2_dirhash(name, name_len);
 836
 837         /*
 838          * Search for the filename in the directory
 839          */
 840         hammer2_inode_lock_ex(dip);
 841
 842         parent = hammer2_chain_lookup_init(dip->chain, 0);
 843         chain = hammer2_chain_lookup(&parent,
 844                                      lhc, lhc + HAMMER2_DIRHASH_LOMASK,
 845                                      0);
 846         while (chain) {
 847                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
 848                     name_len == chain->data->ipdata.name_len &&
 849                     bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
 850                         break;
 851                 }
 852                 chain = hammer2_chain_next(&parent, chain,
 853                                            lhc, lhc + HAMMER2_DIRHASH_LOMASK,
 854                                            0);
 855         }
 856         hammer2_inode_unlock_ex(dip);   /* retain parent */
 857
 858         /*
 859          * Not found or wrong type (isdir < 0 disables the type check).
 860          * If a hardlink pointer, type checks use the hardlink target.
 861          */
 862         if (chain == NULL) {
 863                 error = ENOENT;
 864                 goto done;
 865         }
 866         if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK)
 867                 type = chain->data->ipdata.target_type;
 868
 869         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
 870                 error = ENOTDIR;
 871                 goto done;
 872         }
 873         if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
 874                 error = EISDIR;
 875                 goto done;
 876         }
 877
 878         /*
 879          * Hardlink must be resolved.  We can't hold parent locked while we
 880          * do this or we could deadlock.
 881          *
 882          * On success chain will be adjusted to point at the hardlink target
 883          * and ochain will point to the hardlink pointer in the original
 884          * directory.  Otherwise chain remains pointing to the original.
 885          */
 886         if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
 887                 KKASSERT(parent_ref == 0);
 888                 hammer2_chain_unlock(parent);
 889                 parent = NULL;
 890                 error = hammer2_hardlink_find(dip, &chain, &ochain);
 891         }
 892
 893         /*
 894          * If this is a directory the directory must be empty.  However, if
 895          * isdir < 0 we are doing a rename and the directory does not have
 896          * to be empty.
 897          *
 898          * NOTE: We check the full key range here which covers both visible
 899          *       and invisible entries.  Theoretically there should be no
 900          *       invisible (hardlink target) entries if there are no visible
 901          *       entries.
 902          */
 903         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir >= 0) {
 904                 dparent = hammer2_chain_lookup_init(chain, 0);
 905                 dchain = hammer2_chain_lookup(&dparent,
 906                                               0, (hammer2_key_t)-1,
 907                                               HAMMER2_LOOKUP_NODATA);
 908                 if (dchain) {
 909                         hammer2_chain_unlock(dchain);
 910                         hammer2_chain_lookup_done(dparent);
 911                         error = ENOTEMPTY;
 912                         goto done;
 913                 }
 914                 hammer2_chain_lookup_done(dparent);
 915                 dparent = NULL;
 916                 /* dchain NULL */
 917         }
 918
 919         /*
 920          * Ok, we can now unlink the chain.  We always decrement nlinks even
 921          * if the entry can be deleted in case someone has the file open and
 922          * does an fstat().
 923          *
 924          * The chain itself will no longer be in the on-media topology but
 925          * can still be flushed to the media (e.g. if an open descriptor
 926          * remains).  When the last vnode/ip ref goes away the chain will
 927          * be marked unmodified, avoiding any further (now unnecesary) I/O.
 928          *
 929          * A non-NULL ochain indicates a hardlink.
 930          */
 931         if (ochain) {
 932                 /*
 933                  * Delete the original hardlink pointer.
 934                  *
 935                  * NOTE: parent from above is NULL when ochain != NULL
 936                  *       so we can reuse it.
 937                  */
 938                 hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
 939                 parent_ref = 1;
 940                 for (;;) {
 941                         parent = ochain->parent;
 942                         hammer2_chain_ref(parent);
 943                         hammer2_chain_unlock(ochain);
 944                         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 945                         hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
 946                         if (ochain->parent == parent)
 947                                 break;
 948                         hammer2_chain_unlock(parent);
 949                         hammer2_chain_drop(parent);
 950                 }
 951
 952                 hammer2_chain_delete(trans, parent, ochain);
 953                 hammer2_chain_unlock(ochain);
 954                 hammer2_chain_unlock(parent);
 955                 hammer2_chain_drop(parent);
 956                 parent = NULL;
 957
 958                 /*
 959                  * Then decrement nlinks on hardlink target, deleting
 960                  * the target when nlinks drops to 0.
 961                  */
 962                 if (chain->data->ipdata.nlinks == 1) {
 963                         dparent = chain->parent;
 964                         hammer2_chain_ref(chain);
 965                         hammer2_chain_unlock(chain);
 966                         hammer2_chain_lock(dparent, HAMMER2_RESOLVE_ALWAYS);
 967                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
 968                         hammer2_chain_drop(chain);
 969                         hammer2_chain_modify(trans, chain, 0);
 970                         --chain->data->ipdata.nlinks;
 971                         hammer2_chain_delete(trans, dparent, chain);
 972                         hammer2_chain_unlock(dparent);
 973                 } else {
 974                         hammer2_chain_modify(trans, chain, 0);
 975                         --chain->data->ipdata.nlinks;
 976                 }
 977         } else {
 978                 /*
 979                  * Otherwise this was not a hardlink and we can just
 980                  * remove the entry and decrement nlinks.
 981                  *
 982                  * NOTE: *_get() integrates chain's lock into the inode lock.
 983                  */
 984                 ipdata = &chain->data->ipdata;
 985                 hammer2_chain_modify(trans, chain, 0);
 986                 --ipdata->nlinks;
 987                 hammer2_chain_delete(trans, parent, chain);
 988         }
 989
 990         error = 0;
 991 done:
 992         if (chain)
 993                 hammer2_chain_unlock(chain);
 994         if (parent) {
 995                 hammer2_chain_lookup_done(parent);
 996                 if (parent_ref)
 997                         hammer2_chain_drop(parent);
 998         }
 999         if (ochain)
1000                 hammer2_chain_drop(ochain);
1001
1002         return error;
1003 }
1004
1005 /*
1006  * Calculate the allocation size for the file fragment straddling EOF
1007  */
1008 int
1009 hammer2_inode_calc_alloc(hammer2_key_t filesize)
1010 {
1011         int frag = (int)filesize & HAMMER2_PBUFMASK;
1012         int radix;
1013
1014         if (frag == 0)
1015                 return(0);
1016         for (radix = HAMMER2_MINALLOCRADIX; frag > (1 << radix); ++radix)
1017                 ;
1018         return (radix);
1019 }
1020
1021 /*
1022  * Given an unlocked ip consolidate for hardlink creation, adding (nlinks)
1023  * to the file's link count and potentially relocating the file to a
1024  * directory common to ip->pip and tdip.
1025  *
1026  * If the file has to be relocated ip->chain will also be adjusted.
1027  */
1028 int
1029 hammer2_hardlink_consolidate(hammer2_trans_t *trans, hammer2_inode_t *ip,
1030                              hammer2_chain_t **chainp,
1031                              hammer2_inode_t *tdip, int nlinks)
1032 {
1033         hammer2_inode_data_t *ipdata;
1034         hammer2_mount_t *hmp;
1035         hammer2_inode_t *fdip;
1036         hammer2_inode_t *cdip;
1037         hammer2_chain_t *chain;
1038         hammer2_chain_t *nchain;
1039         hammer2_chain_t *parent;
1040         int error;
1041
1042         /*
1043          * Extra lock on chain so it can be returned locked.
1044          */
1045         hmp = tdip->hmp;
1046         hammer2_inode_lock_ex(ip);
1047
1048         chain = ip->chain;
1049         error = hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
1050         KKASSERT(error == 0);
1051
1052         if (nlinks == 0 &&                      /* no hardlink needed */
1053             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE)) {
1054                 hammer2_inode_unlock_ex(ip);
1055                 *chainp = chain;
1056                 return (0);
1057         }
1058         if (hammer2_hardlink_enable < 0) {      /* fake hardlinks */
1059                 hammer2_inode_unlock_ex(ip);
1060                 *chainp = chain;
1061                 return (0);
1062         }
1063
1064         if (hammer2_hardlink_enable == 0) {     /* disallow hardlinks */
1065                 hammer2_inode_unlock_ex(ip);
1066                 hammer2_chain_unlock(chain);
1067                 *chainp = NULL;
1068                 return (ENOTSUP);
1069         }
1070
1071         /*
1072          * cdip will be returned with a ref, but not locked.
1073          */
1074         fdip = ip->pip;
1075         cdip = hammer2_inode_common_parent(fdip, tdip);
1076
1077         /*
1078          * If no change in the hardlink's target directory is required and
1079          * this is already a hardlink target, all we need to do is adjust
1080          * the link count.
1081          */
1082         if (cdip == fdip &&
1083             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) == 0) {
1084                 if (nlinks) {
1085                         hammer2_chain_modify(trans, chain, 0);
1086                         chain->data->ipdata.nlinks += nlinks;
1087                 }
1088                 *chainp = chain;
1089                 error = 0;
1090                 goto done;
1091         }
1092
1093         /*
1094          * We either have to move an existing hardlink target or we have
1095          * to create a fresh hardlink target.
1096          *
1097          * Hardlink targets are hidden inodes in a parent directory common
1098          * to all directory entries referencing the hardlink.
1099          */
1100         nchain = hammer2_inode_duplicate(trans, chain, cdip, &error);
1101         if (error == 0) {
1102                 /*
1103                  * Bump nlinks on duplicated hidden inode.
1104                  */
1105                 hammer2_chain_modify(trans, nchain, 0);
1106                 nchain->data->ipdata.nlinks += nlinks;
1107
1108                 /*
1109                  * If the old chain is not a hardlink target then replace
1110                  * it with a OBJTYPE_HARDLINK pointer.
1111                  *
1112                  * If the old chain IS a hardlink target then delete it.
1113                  */
1114                 if (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) {
1115                         hammer2_chain_modify(trans, chain, 0);
1116                         ipdata = &chain->data->ipdata;
1117                         ipdata->target_type = ipdata->type;
1118                         ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
1119                         ipdata->uflags = 0;
1120                         ipdata->rmajor = 0;
1121                         ipdata->rminor = 0;
1122                         ipdata->ctime = 0;
1123                         ipdata->mtime = 0;
1124                         ipdata->atime = 0;
1125                         ipdata->btime = 0;
1126                         bzero(&ipdata->uid, sizeof(ipdata->uid));
1127                         bzero(&ipdata->gid, sizeof(ipdata->gid));
1128                         ipdata->op_flags = HAMMER2_OPFLAG_DIRECTDATA;
1129                         ipdata->cap_flags = 0;
1130                         ipdata->mode = 0;
1131                         ipdata->size = 0;
1132                         ipdata->nlinks = 1;
1133                         ipdata->iparent = 0;    /* XXX */
1134                         ipdata->pfs_type = 0;
1135                         ipdata->pfs_inum = 0;
1136                         bzero(&ipdata->pfs_clid, sizeof(ipdata->pfs_clid));
1137                         bzero(&ipdata->pfs_fsid, sizeof(ipdata->pfs_fsid));
1138                         ipdata->data_quota = 0;
1139                         ipdata->data_count = 0;
1140                         ipdata->inode_quota = 0;
1141                         ipdata->inode_count = 0;
1142                         ipdata->attr_tid = 0;
1143                         ipdata->dirent_tid = 0;
1144                         bzero(&ipdata->u, sizeof(ipdata->u));
1145                         /* XXX transaction ids */
1146                 } else {
1147                         kprintf("DELETE INVISIBLE\n");
1148                         for (;;) {
1149                                 parent = chain->parent;
1150                                 hammer2_chain_ref(parent);
1151                                 hammer2_chain_ref(chain);
1152                                 hammer2_chain_unlock(chain);
1153                                 hammer2_chain_lock(parent,
1154                                                    HAMMER2_RESOLVE_ALWAYS);
1155                                 hammer2_chain_lock(chain,
1156                                                    HAMMER2_RESOLVE_ALWAYS);
1157                                 hammer2_chain_drop(chain);
1158                                 if (chain->parent == parent)
1159                                         break;
1160                                 hammer2_chain_unlock(parent);
1161                                 hammer2_chain_drop(parent);
1162                         }
1163                         hammer2_chain_delete(trans, parent, chain);
1164                         hammer2_chain_unlock(parent);
1165                         hammer2_chain_drop(parent);
1166                 }
1167
1168                 /*
1169                  * Replace ip->chain with nchain (ip is still locked).
1170                  */
1171                 hammer2_chain_ref(nchain);              /* ip->chain */
1172                 if (ip->chain)
1173                         hammer2_chain_drop(ip->chain);  /* ip->chain */
1174                 ip->chain = nchain;
1175
1176                 hammer2_chain_unlock(chain);
1177                 *chainp = nchain;
1178         } else {
1179                 hammer2_chain_unlock(chain);
1180                 *chainp = NULL;
1181         }
1182
1183         /*
1184          * Cleanup, chain/nchain already dealt with.
1185          */
1186 done:
1187         hammer2_inode_unlock_ex(ip);
1188         hammer2_inode_drop(cdip);
1189
1190         return (error);
1191 }
1192
1193 /*
1194  * If (*ochainp) is non-NULL it points to the forward OBJTYPE_HARDLINK
1195  * inode while (*chainp) points to the resolved (hidden hardlink
1196  * target) inode.  In this situation when nlinks is 1 we wish to
1197  * deconsolidate the hardlink, moving it back to the directory that now
1198  * represents the only remaining link.
1199  */
1200 int
1201 hammer2_hardlink_deconsolidate(hammer2_trans_t *trans,
1202                                hammer2_inode_t *dip,
1203                                hammer2_chain_t **chainp,
1204                                hammer2_chain_t **ochainp)
1205 {
1206         if (*ochainp == NULL)
1207                 return (0);
1208         /* XXX */
1209         return (0);
1210 }
1211
1212 /*
1213  * The caller presents a locked *chainp pointing to a HAMMER2_BREF_TYPE_INODE
1214  * with an obj_type of HAMMER2_OBJTYPE_HARDLINK.  This routine will gobble
1215  * the *chainp and return a new locked *chainp representing the file target
1216  * (the original *chainp will be unlocked).
1217  *
1218  * When a match is found the chain representing the original HARDLINK
1219  * will be returned in *ochainp with a ref, but not locked.
1220  *
1221  * When no match is found *chainp is set to NULL and EIO is returned.
1222  * (*ochainp) will still be set to the original chain with a ref but not
1223  * locked.
1224  */
1225 int
1226 hammer2_hardlink_find(hammer2_inode_t *dip, hammer2_chain_t **chainp,
1227                       hammer2_chain_t **ochainp)
1228 {
1229         hammer2_chain_t *chain = *chainp;
1230         hammer2_chain_t *parent;
1231         hammer2_inode_t *ip;
1232         hammer2_inode_t *pip;
1233         hammer2_key_t lhc;
1234
1235         pip = dip;
1236         hammer2_inode_ref(pip);         /* for loop */
1237         hammer2_chain_ref(chain);       /* for (*ochainp) */
1238
1239         *ochainp = chain;
1240
1241         /*
1242          * Locate the hardlink.  pip is referenced and not locked,
1243          * ipp.
1244          *
1245          * chain is reused.
1246          */
1247         lhc = chain->data->ipdata.inum;
1248         hammer2_chain_unlock(chain);
1249         chain = NULL;
1250
1251         while ((ip = pip) != NULL) {
1252                 hammer2_inode_lock_ex(ip);
1253                 parent = hammer2_chain_lookup_init(ip->chain, 0);
1254                 hammer2_inode_drop(ip);                 /* loop */
1255                 KKASSERT(parent->bref.type == HAMMER2_BREF_TYPE_INODE);
1256                 chain = hammer2_chain_lookup(&parent, lhc, lhc, 0);
1257                 hammer2_chain_lookup_done(parent);
1258                 if (chain)
1259                         break;
1260                 pip = ip->pip;          /* safe, ip held locked */
1261                 if (pip)
1262                         hammer2_inode_ref(pip);         /* loop */
1263                 hammer2_inode_unlock_ex(ip);
1264         }
1265
1266         /*
1267          * chain is locked, ip is locked.  Unlock ip, return the locked
1268          * chain.  *ipp is already set w/a ref count and not locked.
1269          *
1270          * (parent is already unlocked).
1271          */
1272         if (ip)
1273                 hammer2_inode_unlock_ex(ip);
1274         *chainp = chain;
1275         if (chain) {
1276                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
1277                 /* already locked */
1278                 return (0);
1279         } else {
1280                 return (EIO);
1281         }
1282 }
1283
1284 /*
1285  * Find the directory common to both fdip and tdip, hold and return
1286  * its inode.
1287  */
1288 hammer2_inode_t *
1289 hammer2_inode_common_parent(hammer2_inode_t *fdip, hammer2_inode_t *tdip)
1290 {
1291         hammer2_inode_t *scan1;
1292         hammer2_inode_t *scan2;
1293
1294         /*
1295          * We used to have a depth field but it complicated matters too
1296          * much for directory renames.  So now its ugly.  Check for
1297          * simple cases before giving up and doing it the expensive way.
1298          *
1299          * XXX need a bottom-up topology stability lock
1300          */
1301         if (fdip == tdip || fdip == tdip->pip) {
1302                 hammer2_inode_ref(fdip);
1303                 return(fdip);
1304         }
1305         if (fdip->pip == tdip) {
1306                 hammer2_inode_ref(tdip);
1307                 return(tdip);
1308         }
1309
1310         /*
1311          * XXX not MPSAFE
1312          */
1313         for (scan1 = fdip; scan1->pmp == fdip->pmp; scan1 = scan1->pip) {
1314                 scan2 = tdip;
1315                 while (scan2->pmp == tdip->pmp) {
1316                         if (scan1 == scan2) {
1317                                 hammer2_inode_ref(scan1);
1318                                 return(scan1);
1319                         }
1320                         scan2 = scan2->pip;
1321                 }
1322         }
1323         panic("hammer2_inode_common_parent: no common parent %p %p\n",
1324               fdip, tdip);
1325         /* NOT REACHED */
1326         return(NULL);
1327 }