sys/vfs/hammer2/hammer2_inode.c

   1 /*
   2  * Copyright (c) 2011-2012 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(hmp, 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(hmp, 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, disconnecting it from its chain.  The inode must be
 283  * exclusively locked.
 284  *
 285  * The inode will be unlocked by this function.  Note however that any related
 286  * chain returned by the hammer2_inode_lock_*() call will NOT be unlocked
 287  * by this function.  The related chain is dropped to undo the ref that
 288  * hammer2_inode_get() put on it.
 289  *
 290  * passed_chain is unlocked normally and does not have to be directly
 291  * associated with (ip).  This is simply so the API works the same as
 292  * the hammer2_inode_unlock_ex() API.  NULL is ok.
 293  */
 294 void
 295 hammer2_inode_put(hammer2_inode_t *ip, hammer2_chain_t *passed_chain)
 296 {
 297         hammer2_mount_t *hmp = ip->hmp;
 298         hammer2_inode_t *pip;
 299         hammer2_chain_t *chain;
 300
 301         /*
 302          * Disconnect chain
 303          */
 304         if ((chain = ip->chain) != NULL) {
 305                 ip->chain = NULL;
 306                 hammer2_chain_drop(hmp, chain);         /* from *_get() */
 307         }
 308         KKASSERT(ip->topo_cst.count == -1);     /* one excl lock allowed */
 309
 310         /*
 311          * Disconnect pip
 312          */
 313         if ((pip = ip->pip) != NULL) {
 314                 ip->pip = NULL;
 315                 hammer2_inode_drop(pip);
 316         }
 317
 318         /*
 319          * clean up the ip, we use an inode_unlock_ex-compatible API.
 320          */
 321         hammer2_inode_unlock_ex(ip, passed_chain);
 322 }
 323
 324 /*
 325  * Create a new inode in the specified directory using the vattr to
 326  * figure out the type of inode.
 327  *
 328  * If no error occurs the new inode with its chain locked is returned in
 329  * *nipp, otherwise an error is returned and *nipp is set to NULL.
 330  *
 331  * If vap and/or cred are NULL the related fields are not set and the
 332  * inode type defaults to a directory.  This is used when creating PFSs
 333  * under the super-root, so the inode number is set to 1 in this case.
 334  *
 335  * dip is not locked on entry.
 336  */
 337 int
 338 hammer2_inode_create(hammer2_inode_t *dip,
 339                      struct vattr *vap, struct ucred *cred,
 340                      const uint8_t *name, size_t name_len,
 341                      hammer2_inode_t **nipp, hammer2_chain_t **nchainp)
 342 {
 343         hammer2_inode_data_t *nipdata;
 344         hammer2_mount_t *hmp;
 345         hammer2_chain_t *chain;
 346         hammer2_chain_t *parent;
 347         hammer2_inode_t *nip;
 348         hammer2_key_t lhc;
 349         int error;
 350         uid_t xuid;
 351         uuid_t dip_uid;
 352         uuid_t dip_gid;
 353         uint32_t dip_mode;
 354
 355         hmp = dip->hmp;
 356         lhc = hammer2_dirhash(name, name_len);
 357
 358         /*
 359          * Locate the inode or indirect block to create the new
 360          * entry in.  At the same time check for key collisions
 361          * and iterate until we don't get one.
 362          */
 363 retry:
 364         parent = hammer2_inode_lock_ex(dip);
 365
 366         dip_uid = parent->data->ipdata.uid;
 367         dip_gid = parent->data->ipdata.gid;
 368         dip_mode = parent->data->ipdata.mode;
 369
 370         error = 0;
 371         while (error == 0) {
 372                 chain = hammer2_chain_lookup(hmp, &parent, lhc, lhc, 0);
 373                 if (chain == NULL)
 374                         break;
 375                 if ((lhc & HAMMER2_DIRHASH_VISIBLE) == 0)
 376                         error = ENOSPC;
 377                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 378                         error = ENOSPC;
 379                 hammer2_chain_unlock(hmp, chain);
 380                 chain = NULL;
 381                 ++lhc;
 382         }
 383         if (error == 0) {
 384                 chain = hammer2_chain_create(hmp, parent, NULL, lhc, 0,
 385                                              HAMMER2_BREF_TYPE_INODE,
 386                                              HAMMER2_INODE_BYTES,
 387                                              &error);
 388         }
 389
 390         hammer2_inode_unlock_ex(dip, parent);
 391
 392         /*
 393          * Handle the error case
 394          */
 395         if (error) {
 396                 KKASSERT(chain == NULL);
 397                 if (error == EAGAIN) {
 398                         hammer2_chain_wait(hmp, parent);
 399                         goto retry;
 400                 }
 401                 *nipp = NULL;
 402                 *nchainp = NULL;
 403                 return (error);
 404         }
 405
 406         /*
 407          * Set up the new inode.
 408          *
 409          * NOTE: *_get() integrates chain's lock into the inode lock.
 410          */
 411         nip = hammer2_inode_get(dip->hmp, dip->pmp, dip, chain);
 412         *nipp = nip;
 413         *nchainp = chain;
 414         nipdata = &chain->data->ipdata;
 415
 416         hammer2_voldata_lock(hmp);
 417         if (vap) {
 418                 nipdata->type = hammer2_get_obj_type(vap->va_type);
 419                 nipdata->inum = hmp->voldata.alloc_tid++;
 420                 /* XXX modify/lock */
 421         } else {
 422                 nipdata->type = HAMMER2_OBJTYPE_DIRECTORY;
 423                 nipdata->inum = 1;
 424         }
 425         hammer2_voldata_unlock(hmp);
 426         nipdata->version = HAMMER2_INODE_VERSION_ONE;
 427         hammer2_update_time(&nipdata->ctime);
 428         nipdata->mtime = nipdata->ctime;
 429         if (vap)
 430                 nipdata->mode = vap->va_mode;
 431         nipdata->nlinks = 1;
 432         if (vap) {
 433                 if (dip) {
 434                         xuid = hammer2_to_unix_xid(&dip_uid);
 435                         xuid = vop_helper_create_uid(dip->pmp->mp,
 436                                                      dip_mode,
 437                                                      xuid,
 438                                                      cred,
 439                                                      &vap->va_mode);
 440                 } else {
 441                         xuid = 0;
 442                 }
 443                 if (vap->va_vaflags & VA_UID_UUID_VALID)
 444                         nipdata->uid = vap->va_uid_uuid;
 445                 else if (vap->va_uid != (uid_t)VNOVAL)
 446                         hammer2_guid_to_uuid(&nipdata->uid, vap->va_uid);
 447                 else
 448                         hammer2_guid_to_uuid(&nipdata->uid, xuid);
 449
 450                 if (vap->va_vaflags & VA_GID_UUID_VALID)
 451                         nipdata->gid = vap->va_gid_uuid;
 452                 else if (vap->va_gid != (gid_t)VNOVAL)
 453                         hammer2_guid_to_uuid(&nipdata->gid, vap->va_gid);
 454                 else if (dip)
 455                         nipdata->gid = dip_gid;
 456         }
 457
 458         /*
 459          * Regular files and softlinks allow a small amount of data to be
 460          * directly embedded in the inode.  This flag will be cleared if
 461          * the size is extended past the embedded limit.
 462          */
 463         if (nipdata->type == HAMMER2_OBJTYPE_REGFILE ||
 464             nipdata->type == HAMMER2_OBJTYPE_SOFTLINK) {
 465                 nipdata->op_flags |= HAMMER2_OPFLAG_DIRECTDATA;
 466         }
 467
 468         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 469         bcopy(name, nipdata->filename, name_len);
 470         nipdata->name_key = lhc;
 471         nipdata->name_len = name_len;
 472
 473         return (0);
 474 }
 475
 476 /*
 477  * Create a duplicate of the inode (chain) in the specified target directory
 478  * (dip), return the duplicated chain in *nchainp (locked).  chain is locked
 479  * on call and remains locked on return.
 480  *
 481  * If name is NULL the inode is duplicated as a hidden directory entry.
 482  *
 483  * XXX name needs to be NULL for now.
 484  */
 485 int
 486 hammer2_inode_duplicate(hammer2_inode_t *dip,
 487                         hammer2_chain_t *ochain, hammer2_chain_t **nchainp)
 488 {
 489         hammer2_inode_data_t *nipdata;
 490         hammer2_mount_t *hmp;
 491         hammer2_chain_t *parent;
 492         hammer2_chain_t *chain;
 493         hammer2_key_t lhc;
 494         int error = 0;
 495
 496         hmp = dip->hmp;
 497         lhc = ochain->data->ipdata.inum;
 498         *nchainp = NULL;
 499         KKASSERT((lhc & HAMMER2_DIRHASH_VISIBLE) == 0);
 500
 501         /*
 502          * Locate the inode or indirect block to create the new
 503          * entry in.
 504          *
 505          * There should be no key collisions with invisible inode keys.
 506          */
 507 retry:
 508         parent = dip->chain;
 509         hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS);
 510         chain = hammer2_chain_lookup(hmp, &parent, lhc, lhc, 0);
 511         if (chain) {
 512                 hammer2_chain_unlock(hmp, chain);
 513                 chain = NULL;
 514                 error = ENOSPC;
 515         }
 516
 517         /*
 518          * Create entry in common parent directory.
 519          */
 520         if (error == 0) {
 521                 chain = hammer2_chain_create(hmp, parent, NULL, lhc, 0,
 522                                              HAMMER2_BREF_TYPE_INODE, /* n/a */
 523                                              HAMMER2_INODE_BYTES,     /* n/a */
 524                                              &error);
 525         }
 526
 527         /*
 528          * Clean up, but we need to retain a ref on parent so we can wait
 529          * on it for certain errors.
 530          */
 531         if (error == EAGAIN)
 532                 hammer2_chain_ref(hmp, parent);
 533         hammer2_chain_unlock(hmp, parent);
 534
 535         /*
 536          * Handle the error case
 537          */
 538         if (error) {
 539                 KKASSERT(chain == NULL);
 540                 if (error == EAGAIN) {
 541                         hammer2_chain_wait(hmp, parent);
 542                         hammer2_chain_drop(hmp, parent);
 543                         goto retry;
 544                 }
 545                 return (error);
 546         }
 547
 548         /*
 549          * XXX This is currently a horrible hack.  Well, if we wanted to
 550          *     duplicate a file, i.e. as in a snapshot, we definitely
 551          *     would have to flush it first.
 552          *
 553          *     For hardlink target generation we can theoretically move any
 554          *     active chain structures without flushing, but that gets really
 555          *     iffy for code which follows chain->parent and ip->pip links.
 556          *
 557          * XXX only works with files.  Duplicating a directory hierarchy
 558          *     requires a flush but doesn't deal with races post-flush.
 559          *     Well, it would work I guess, but you might catch some files
 560          *     mid-operation.
 561          *
 562          * We cannot leave ochain with any in-memory chains because (for a
 563          * hardlink), ochain will become a OBJTYPE_HARDLINK which is just a
 564          * pointer to the real hardlink's inum and can't have any sub-chains.
 565          * XXX might be 0-ref chains left.
 566          */
 567         hammer2_chain_flush(hmp, ochain, 0);
 568         /*KKASSERT(RB_EMPTY(&ochain.rbhead));*/
 569
 570         hammer2_chain_modify(hmp, chain, 0);
 571         nipdata = &chain->data->ipdata;
 572         *nipdata = ochain->data->ipdata;
 573
 574         /*
 575          * Directory entries are inodes but this is a hidden hardlink
 576          * target.  The name isn't used but to ease debugging give it
 577          * a name after its inode number.
 578          */
 579         ksnprintf(nipdata->filename, sizeof(nipdata->filename),
 580                   "0x%016jx", (intmax_t)nipdata->inum);
 581         nipdata->name_len = strlen(nipdata->filename);
 582         nipdata->name_key = lhc;
 583
 584         *nchainp = chain;
 585
 586         return (0);
 587 }
 588
 589 /*
 590  * Connect *chainp to the media topology represented by (dip, name, len).
 591  * A directory entry is created which points to *chainp.  *chainp is then
 592  * unlocked and set to NULL.
 593  *
 594  * If *chainp is not currently connected we simply connect it up.
 595  *
 596  * If *chainp is already connected we create a OBJTYPE_HARDLINK entry which
 597  * points to chain's inode number.  *chainp is expected to be the terminus of
 598  * the hardlink sitting as a hidden file in a common parent directory
 599  * in this situation.
 600  *
 601  * The caller always wants to reference the hardlink terminus, not the
 602  * hardlink pointer that we might be creating, so we do NOT replace
 603  * *chainp here, we simply unlock and NULL it out.
 604  */
 605 int
 606 hammer2_inode_connect(hammer2_inode_t *dip, hammer2_chain_t **chainp,
 607                       const uint8_t *name, size_t name_len)
 608 {
 609         hammer2_inode_data_t *ipdata;
 610         hammer2_mount_t *hmp;
 611         hammer2_chain_t *nchain;
 612         hammer2_chain_t *parent;
 613         hammer2_chain_t *ochain;
 614         hammer2_key_t lhc;
 615         int error;
 616         int hlink;
 617
 618         hmp = dip->hmp;
 619
 620         ochain = *chainp;
 621         *chainp = NULL;
 622
 623         /*
 624          * Since ochain is either disconnected from the topology or represents
 625          * a hardlink terminus which is always a parent of or equal to dip,
 626          * we should be able to safely lock dip->chain for our setup.
 627          */
 628 retry:
 629         parent = dip->chain;
 630         hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS);
 631
 632         lhc = hammer2_dirhash(name, name_len);
 633         hlink = (ochain->parent != NULL);
 634
 635         /*
 636          * In fake mode flush oip so we can just snapshot it downbelow.
 637          */
 638         if (hlink && hammer2_hardlink_enable < 0)
 639                 hammer2_chain_flush(hmp, ochain, 0);
 640
 641         /*
 642          * Locate the inode or indirect block to create the new
 643          * entry in.  At the same time check for key collisions
 644          * and iterate until we don't get one.
 645          */
 646         error = 0;
 647         while (error == 0) {
 648                 nchain = hammer2_chain_lookup(hmp, &parent, lhc, lhc, 0);
 649                 if (nchain == NULL)
 650                         break;
 651                 if ((lhc & HAMMER2_DIRHASH_LOMASK) == HAMMER2_DIRHASH_LOMASK)
 652                         error = ENOSPC;
 653                 hammer2_chain_unlock(hmp, nchain);
 654                 nchain = NULL;
 655                 ++lhc;
 656         }
 657
 658         /*
 659          * Passing a non-NULL chain to hammer2_chain_create() reconnects the
 660          * existing chain instead of creating a new one.  The chain's bref
 661          * will be properly updated.
 662          */
 663         if (error == 0) {
 664                 if (hlink) {
 665                         nchain = hammer2_chain_create(hmp, parent,
 666                                                      NULL, lhc, 0,
 667                                                      HAMMER2_BREF_TYPE_INODE,
 668                                                      HAMMER2_INODE_BYTES,
 669                                                      &error);
 670                 } else {
 671                         /*
 672                          * NOTE: reconnects oip->chain to the media
 673                          *       topology and returns its argument
 674                          *       (oip->chain).
 675                          *
 676                          * No additional locks or refs are obtained on
 677                          * the returned chain so don't double-unlock!
 678                          */
 679                         nchain = hammer2_chain_create(hmp, parent,
 680                                                      ochain, lhc, 0,
 681                                                      HAMMER2_BREF_TYPE_INODE,
 682                                                      HAMMER2_INODE_BYTES,
 683                                                      &error);
 684                 }
 685         }
 686
 687         /*
 688          * Unlock stuff.  This is a bit messy, if we have an EAGAIN error
 689          * we need to wait for operations on parent to finish.
 690          */
 691         if (error == EAGAIN)
 692                 hammer2_chain_ref(hmp, parent);
 693         hammer2_chain_unlock(hmp, parent);
 694
 695         /*
 696          * ochain still active.
 697          *
 698          * Handle the error case
 699          */
 700         if (error) {
 701                 KKASSERT(nchain == NULL);
 702                 if (error == EAGAIN) {
 703                         hammer2_chain_wait(hmp, parent);
 704                         hammer2_chain_drop(hmp, parent);
 705                         goto retry;
 706                 }
 707                 hammer2_chain_unlock(hmp, ochain);
 708                 return (error);
 709         }
 710
 711         /*
 712          * Directory entries are inodes so if the name has changed we have
 713          * to update the inode.
 714          *
 715          * When creating an OBJTYPE_HARDLINK entry remember to unlock the
 716          * chain, the caller will access the hardlink via the actual hardlink
 717          * target file and not the hardlink pointer entry.
 718          */
 719         if (hlink && hammer2_hardlink_enable >= 0) {
 720                 /*
 721                  * Create the HARDLINK pointer.  oip represents the hardlink
 722                  * target in this situation.
 723                  *
 724                  * NOTE: *_get() integrates chain's lock into the inode lock.
 725                  */
 726                 hammer2_chain_modify(hmp, nchain, 0);
 727                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 728                 ipdata = &nchain->data->ipdata;
 729                 bcopy(name, ipdata->filename, name_len);
 730                 ipdata->name_key = lhc;
 731                 ipdata->name_len = name_len;
 732                 ipdata->target_type = ochain->data->ipdata.type;
 733                 ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
 734                 ipdata->inum = ochain->data->ipdata.inum;
 735                 ipdata->nlinks = 1;
 736                 kprintf("created hardlink %*.*s\n",
 737                         (int)name_len, (int)name_len, name);
 738                 hammer2_chain_unlock(hmp, nchain);
 739         } else if (hlink && hammer2_hardlink_enable < 0) {
 740                 /*
 741                  * Create a snapshot (hardlink fake mode for debugging).
 742                  *
 743                  * NOTE: *_get() integrates nchain's lock into the inode lock.
 744                  */
 745                 hammer2_chain_modify(hmp, nchain, 0);
 746                 KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 747                 ipdata = &nchain->data->ipdata;
 748                 *ipdata = ochain->data->ipdata;
 749                 bcopy(name, ipdata->filename, name_len);
 750                 ipdata->name_key = lhc;
 751                 ipdata->name_len = name_len;
 752                 kprintf("created fake hardlink %*.*s\n",
 753                         (int)name_len, (int)name_len, name);
 754                 hammer2_chain_unlock(hmp, nchain);
 755         } else {
 756                 /*
 757                  * Normally disconnected inode (e.g. during a rename) that
 758                  * was reconnected.  We must fixup the name stored in
 759                  * oip.
 760                  *
 761                  * We are using oip as chain, already locked by caller,
 762                  * do not unlock it.
 763                  */
 764                 hammer2_chain_modify(hmp, ochain, 0);
 765                 ipdata = &ochain->data->ipdata;
 766
 767                 if (ipdata->name_len != name_len ||
 768                     bcmp(ipdata->filename, name, name_len) != 0) {
 769                         KKASSERT(name_len < HAMMER2_INODE_MAXNAME);
 770                         bcopy(name, ipdata->filename, name_len);
 771                         ipdata->name_key = lhc;
 772                         ipdata->name_len = name_len;
 773                 }
 774                 ipdata->nlinks = 1;
 775         }
 776         hammer2_chain_unlock(hmp, ochain);
 777         return (0);
 778 }
 779
 780 /*
 781  * Unlink the file from the specified directory inode.  The directory inode
 782  * does not need to be locked.  The caller should pass a non-NULL (ip)
 783  * representing the object being removed only if the related vnode is
 784  * potentially inactive (not referenced in the caller's active path),
 785  * so we can vref/vrele it to trigger the VOP_INACTIVE path and properly
 786  * recycle it.
 787  *
 788  * isdir determines whether a directory/non-directory check should be made.
 789  * No check is made if isdir is set to -1.
 790  *
 791  * If retain_chain is non-NULL this function can fail with an EAGAIN if it
 792  * catches the object in the middle of a flush.
 793  */
 794 int
 795 hammer2_unlink_file(hammer2_inode_t *dip,
 796                     const uint8_t *name, size_t name_len,
 797                     int isdir, hammer2_chain_t *retain_chain)
 798 {
 799         hammer2_inode_data_t *ipdata;
 800         hammer2_mount_t *hmp;
 801         hammer2_chain_t *parent;
 802         hammer2_chain_t *ochain;
 803         hammer2_chain_t *chain;
 804         hammer2_chain_t *dparent;
 805         hammer2_chain_t *dchain;
 806         hammer2_key_t lhc;
 807         int error;
 808         int parent_ref;
 809         uint8_t type;
 810
 811         parent_ref = 0;
 812         error = 0;
 813         ochain = NULL;
 814         hmp = dip->hmp;
 815         lhc = hammer2_dirhash(name, name_len);
 816
 817         /*
 818          * Search for the filename in the directory
 819          */
 820         parent = hammer2_inode_lock_ex(dip);
 821         chain = hammer2_chain_lookup(hmp, &parent,
 822                                      lhc, lhc + HAMMER2_DIRHASH_LOMASK,
 823                                      0);
 824         while (chain) {
 825                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
 826                     name_len == chain->data->ipdata.name_len &&
 827                     bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
 828                         break;
 829                 }
 830                 chain = hammer2_chain_next(hmp, &parent, chain,
 831                                            lhc, lhc + HAMMER2_DIRHASH_LOMASK,
 832                                            0);
 833         }
 834         hammer2_inode_unlock_ex(dip, NULL);     /* retain parent */
 835
 836         /*
 837          * Not found or wrong type (isdir < 0 disables the type check).
 838          * If a hardlink pointer, type checks use the hardlink target.
 839          */
 840         if (chain == NULL) {
 841                 error = ENOENT;
 842                 goto done;
 843         }
 844         if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK)
 845                 type = chain->data->ipdata.target_type;
 846
 847         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
 848                 error = ENOTDIR;
 849                 goto done;
 850         }
 851         if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
 852                 error = EISDIR;
 853                 goto done;
 854         }
 855
 856         /*
 857          * Hardlink must be resolved.  We can't hold parent locked while we
 858          * do this or we could deadlock.
 859          *
 860          * On success chain will be adjusted to point at the hardlink target
 861          * and ochain will point to the hardlink pointer in the original
 862          * directory.  Otherwise chain remains pointing to the original.
 863          */
 864         if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
 865                 KKASSERT(parent_ref == 0);
 866                 hammer2_chain_unlock(hmp, parent);
 867                 parent = NULL;
 868                 error = hammer2_hardlink_find(dip, &chain, &ochain);
 869         }
 870
 871         /*
 872          * If this is a directory the directory must be empty.  However, if
 873          * isdir < 0 we are doing a rename and the directory does not have
 874          * to be empty.
 875          *
 876          * NOTE: We check the full key range here which covers both visible
 877          *       and invisible entries.  Theoretically there should be no
 878          *       invisible (hardlink target) entries if there are no visible
 879          *       entries.
 880          */
 881         if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir >= 0) {
 882                 dparent = chain;
 883                 hammer2_chain_lock(hmp, dparent, HAMMER2_RESOLVE_ALWAYS);
 884                 dchain = hammer2_chain_lookup(hmp, &dparent,
 885                                               0, (hammer2_key_t)-1,
 886                                               HAMMER2_LOOKUP_NODATA);
 887                 if (dchain) {
 888                         hammer2_chain_unlock(hmp, dchain);
 889                         hammer2_chain_unlock(hmp, dparent);
 890                         error = ENOTEMPTY;
 891                         goto done;
 892                 }
 893                 hammer2_chain_unlock(hmp, dparent);
 894                 dparent = NULL;
 895                 /* dchain NULL */
 896         }
 897
 898         /*
 899          * Ok, we can now unlink the chain.  We always decrement nlinks even
 900          * if the entry can be deleted in case someone has the file open and
 901          * does an fstat().
 902          *
 903          * The chain itself will no longer be in the on-media topology but
 904          * can still be flushed to the media (e.g. if an open descriptor
 905          * remains).  When the last vnode/ip ref goes away the chain will
 906          * be marked unmodified, avoiding any further (now unnecesary) I/O.
 907          *
 908          * A non-NULL ochain indicates a hardlink.
 909          */
 910         if (ochain) {
 911                 /*
 912                  * Delete the original hardlink pointer.
 913                  *
 914                  * NOTE: parent from above is NULL when ochain != NULL
 915                  *       so we can reuse it.
 916                  */
 917                 hammer2_chain_lock(hmp, ochain, HAMMER2_RESOLVE_ALWAYS);
 918                 parent_ref = 1;
 919                 for (;;) {
 920                         parent = ochain->parent;
 921                         hammer2_chain_ref(hmp, parent);
 922                         hammer2_chain_unlock(hmp, ochain);
 923                         hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS);
 924                         hammer2_chain_lock(hmp, ochain, HAMMER2_RESOLVE_ALWAYS);
 925                         if (ochain->parent == parent)
 926                                 break;
 927                         hammer2_chain_unlock(hmp, parent);
 928                         hammer2_chain_drop(hmp, parent);
 929                 }
 930
 931                 if (ochain == retain_chain && ochain->flushing) {
 932                         hammer2_chain_unlock(hmp, ochain);
 933                         error = EAGAIN;
 934                         goto done;
 935                 }
 936                 hammer2_chain_delete(hmp, parent, ochain,
 937                                      (ochain == retain_chain));
 938                 hammer2_chain_unlock(hmp, ochain);
 939                 hammer2_chain_unlock(hmp, parent);
 940                 hammer2_chain_drop(hmp, parent);
 941                 parent = NULL;
 942
 943                 /*
 944                  * Then decrement nlinks on hardlink target, deleting
 945                  * the target when nlinks drops to 0.
 946                  */
 947                 if (chain->data->ipdata.nlinks == 1) {
 948                         dparent = chain->parent;
 949                         hammer2_chain_ref(hmp, chain);
 950                         hammer2_chain_unlock(hmp, chain);
 951                         hammer2_chain_lock(hmp, dparent,
 952                                            HAMMER2_RESOLVE_ALWAYS);
 953                         hammer2_chain_lock(hmp, chain,
 954                                            HAMMER2_RESOLVE_ALWAYS);
 955                         hammer2_chain_drop(hmp, chain);
 956                         hammer2_chain_modify(hmp, chain, 0);
 957                         --chain->data->ipdata.nlinks;
 958                         hammer2_chain_delete(hmp, dparent, chain, 0);
 959                         hammer2_chain_unlock(hmp, dparent);
 960                 } else {
 961                         hammer2_chain_modify(hmp, chain, 0);
 962                         --chain->data->ipdata.nlinks;
 963                 }
 964         } else {
 965                 /*
 966                  * Otherwise this was not a hardlink and we can just
 967                  * remove the entry and decrement nlinks.
 968                  *
 969                  * NOTE: *_get() integrates chain's lock into the inode lock.
 970                  */
 971                 ipdata = &chain->data->ipdata;
 972                 if (chain == retain_chain && chain->flushing) {
 973                         error = EAGAIN;
 974                         goto done;
 975                 }
 976                 hammer2_chain_modify(hmp, chain, 0);
 977                 --ipdata->nlinks;
 978                 hammer2_chain_delete(hmp, parent, chain,
 979                                      (retain_chain == chain));
 980         }
 981
 982         error = 0;
 983 done:
 984         if (chain)
 985                 hammer2_chain_unlock(hmp, chain);
 986         if (parent) {
 987                 hammer2_chain_unlock(hmp, parent);
 988                 if (parent_ref)
 989                         hammer2_chain_drop(hmp, parent);
 990         }
 991         if (ochain)
 992                 hammer2_chain_drop(hmp, ochain);
 993
 994         return error;
 995 }
 996
 997 /*
 998  * Calculate the allocation size for the file fragment straddling EOF
 999  */
1000 int
1001 hammer2_inode_calc_alloc(hammer2_key_t filesize)
1002 {
1003         int frag = (int)filesize & HAMMER2_PBUFMASK;
1004         int radix;
1005
1006         if (frag == 0)
1007                 return(0);
1008         for (radix = HAMMER2_MINALLOCRADIX; frag > (1 << radix); ++radix)
1009                 ;
1010         return (radix);
1011 }
1012
1013 /*
1014  * Given an unlocked ip consolidate for hardlink creation, adding (nlinks)
1015  * to the file's link count and potentially relocating the file to a
1016  * directory common to ip->pip and tdip.
1017  *
1018  * If the file has to be relocated ip->chain will also be adjusted.
1019  */
1020 int
1021 hammer2_hardlink_consolidate(hammer2_inode_t *ip, hammer2_chain_t **chainp,
1022                              hammer2_inode_t *tdip, int nlinks)
1023 {
1024         hammer2_inode_data_t *ipdata;
1025         hammer2_mount_t *hmp;
1026         hammer2_inode_t *fdip;
1027         hammer2_inode_t *cdip;
1028         hammer2_chain_t *chain;
1029         hammer2_chain_t *nchain;
1030         hammer2_chain_t *parent;
1031         int error;
1032
1033         hmp = tdip->hmp;
1034         *chainp = NULL;
1035         chain = hammer2_inode_lock_ex(ip);
1036
1037         if (nlinks == 0 &&                      /* no hardlink needed */
1038             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE)) {
1039                 hammer2_inode_unlock_ex(ip, NULL);
1040                 *chainp = chain;
1041                 return (0);
1042         }
1043         if (hammer2_hardlink_enable < 0) {      /* fake hardlinks */
1044                 hammer2_inode_unlock_ex(ip, NULL);
1045                 *chainp = chain;
1046                 return (0);
1047         }
1048         if (hammer2_hardlink_enable == 0) {     /* disallow hardlinks */
1049                 hammer2_inode_unlock_ex(ip, chain);
1050                 return (ENOTSUP);
1051         }
1052
1053         /*
1054          * cdip will be returned with a ref, but not locked.
1055          */
1056         fdip = ip->pip;
1057         cdip = hammer2_inode_common_parent(hmp, fdip, tdip);
1058
1059         /*
1060          * If no change in the hardlink's target directory is required and
1061          * this is already a hardlink target, all we need to do is adjust
1062          * the link count.
1063          */
1064         if (cdip == fdip &&
1065             (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) == 0) {
1066                 if (nlinks) {
1067                         hammer2_chain_modify(hmp, chain, 0);
1068                         chain->data->ipdata.nlinks += nlinks;
1069                 }
1070                 *chainp = chain;
1071                 error = 0;
1072                 goto done;
1073         }
1074
1075         /*
1076          * We either have to move an existing hardlink target or we have
1077          * to create a fresh hardlink target.
1078          *
1079          * Hardlink targets are hidden inodes in a parent directory common
1080          * to all directory entries referencing the hardlink.
1081          */
1082         error = hammer2_inode_duplicate(cdip, chain, &nchain);
1083         if (error == 0) {
1084                 /*
1085                  * Bump nlinks on duplicated hidden inode.
1086                  */
1087                 hammer2_chain_modify(hmp, nchain, 0);
1088                 nchain->data->ipdata.nlinks += nlinks;
1089
1090                 /*
1091                  * If the old chain is not a hardlink target then replace
1092                  * it with a OBJTYPE_HARDLINK pointer.
1093                  *
1094                  * If the old chain IS a hardlink target then delete it.
1095                  */
1096                 if (chain->data->ipdata.name_key & HAMMER2_DIRHASH_VISIBLE) {
1097                         hammer2_chain_modify(hmp, chain, 0);
1098                         ipdata = &chain->data->ipdata;
1099                         ipdata->target_type = ipdata->type;
1100                         ipdata->type = HAMMER2_OBJTYPE_HARDLINK;
1101                         ipdata->uflags = 0;
1102                         ipdata->rmajor = 0;
1103                         ipdata->rminor = 0;
1104                         ipdata->ctime = 0;
1105                         ipdata->mtime = 0;
1106                         ipdata->atime = 0;
1107                         ipdata->btime = 0;
1108                         bzero(&ipdata->uid, sizeof(ipdata->uid));
1109                         bzero(&ipdata->gid, sizeof(ipdata->gid));
1110                         ipdata->op_flags = HAMMER2_OPFLAG_DIRECTDATA;
1111                         ipdata->cap_flags = 0;
1112                         ipdata->mode = 0;
1113                         ipdata->size = 0;
1114                         ipdata->nlinks = 1;
1115                         ipdata->iparent = 0;    /* XXX */
1116                         ipdata->pfs_type = 0;
1117                         ipdata->pfs_inum = 0;
1118                         bzero(&ipdata->pfs_clid, sizeof(ipdata->pfs_clid));
1119                         bzero(&ipdata->pfs_fsid, sizeof(ipdata->pfs_fsid));
1120                         ipdata->data_quota = 0;
1121                         ipdata->data_count = 0;
1122                         ipdata->inode_quota = 0;
1123                         ipdata->inode_count = 0;
1124                         ipdata->attr_tid = 0;
1125                         ipdata->dirent_tid = 0;
1126                         bzero(&ipdata->u, sizeof(ipdata->u));
1127                         /* XXX transaction ids */
1128                 } else {
1129                         kprintf("DELETE INVISIBLE\n");
1130                         for (;;) {
1131                                 parent = chain->parent;
1132                                 hammer2_chain_ref(hmp, parent);
1133                                 hammer2_chain_ref(hmp, chain);
1134                                 hammer2_chain_unlock(hmp, chain);
1135                                 hammer2_chain_lock(hmp, parent,
1136                                                    HAMMER2_RESOLVE_ALWAYS);
1137                                 hammer2_chain_lock(hmp, chain,
1138                                                    HAMMER2_RESOLVE_ALWAYS);
1139                                 hammer2_chain_drop(hmp, chain);
1140                                 if (chain->parent == parent)
1141                                         break;
1142                                 hammer2_chain_unlock(hmp, parent);
1143                                 hammer2_chain_drop(hmp, parent);
1144                         }
1145                         hammer2_chain_delete(hmp, parent, chain, 0);
1146                         hammer2_chain_unlock(hmp, parent);
1147                         hammer2_chain_drop(hmp, parent);
1148                 }
1149
1150                 /*
1151                  * Replace ip->chain with nchain (ip is still locked).
1152                  */
1153                 hammer2_chain_ref(hmp, nchain);                 /* ip->chain */
1154                 if (ip->chain)
1155                         hammer2_chain_drop(hmp, ip->chain);     /* ip->chain */
1156                 ip->chain = nchain;
1157
1158                 hammer2_chain_unlock(hmp, chain);
1159                 *chainp = nchain;
1160         } else {
1161                 hammer2_chain_unlock(hmp, chain);
1162         }
1163
1164         /*
1165          * Cleanup, chain/nchain already dealt with.
1166          */
1167 done:
1168         hammer2_inode_unlock_ex(ip, NULL);
1169         hammer2_inode_drop(cdip);
1170
1171         return (error);
1172 }
1173
1174 /*
1175  * If (*ochainp) is non-NULL it points to the forward OBJTYPE_HARDLINK
1176  * inode while (*chainp) points to the resolved (hidden hardlink
1177  * target) inode.  In this situation when nlinks is 1 we wish to
1178  * deconsolidate the hardlink, moving it back to the directory that now
1179  * represents the only remaining link.
1180  */
1181 int
1182 hammer2_hardlink_deconsolidate(hammer2_inode_t *dip,
1183                                hammer2_chain_t **chainp,
1184                                hammer2_chain_t **ochainp)
1185 {
1186         if (*ochainp == NULL)
1187                 return (0);
1188         /* XXX */
1189         return (0);
1190 }
1191
1192 /*
1193  * The caller presents a locked *chainp pointing to a HAMMER2_BREF_TYPE_INODE
1194  * with an obj_type of HAMMER2_OBJTYPE_HARDLINK.  This routine will gobble
1195  * the *chainp and return a new locked *chainp representing the file target
1196  * (the original *chainp will be unlocked).
1197  *
1198  * When a match is found the chain representing the original HARDLINK
1199  * will be returned in *ochainp with a ref, but not locked.
1200  *
1201  * When no match is found *chainp is set to NULL and EIO is returned.
1202  * (*ochainp) will still be set to the original chain with a ref but not
1203  * locked.
1204  */
1205 int
1206 hammer2_hardlink_find(hammer2_inode_t *dip, hammer2_chain_t **chainp,
1207                       hammer2_chain_t **ochainp)
1208 {
1209         hammer2_mount_t *hmp = dip->hmp;
1210         hammer2_chain_t *chain = *chainp;
1211         hammer2_chain_t *parent;
1212         hammer2_inode_t *ip;
1213         hammer2_inode_t *pip;
1214         hammer2_key_t lhc;
1215
1216         pip = dip;
1217         hammer2_inode_ref(pip);         /* for loop */
1218         hammer2_chain_ref(hmp, chain);  /* for (*ochainp) */
1219
1220         *ochainp = chain;
1221
1222         /*
1223          * Locate the hardlink.  pip is referenced and not locked,
1224          * ipp.
1225          *
1226          * chain is reused.
1227          */
1228         lhc = chain->data->ipdata.inum;
1229         hammer2_chain_unlock(hmp, chain);
1230         chain = NULL;
1231
1232         while ((ip = pip) != NULL) {
1233                 parent = hammer2_inode_lock_ex(ip);
1234                 hammer2_inode_drop(ip);                 /* loop */
1235                 KKASSERT(parent->bref.type == HAMMER2_BREF_TYPE_INODE);
1236                 chain = hammer2_chain_lookup(hmp, &parent, lhc, lhc, 0);
1237                 hammer2_chain_unlock(hmp, parent);
1238                 if (chain)
1239                         break;
1240                 pip = ip->pip;          /* safe, ip held locked */
1241                 if (pip)
1242                         hammer2_inode_ref(pip);         /* loop */
1243                 hammer2_inode_unlock_ex(ip, NULL);
1244         }
1245
1246         /*
1247          * chain is locked, ip is locked.  Unlock ip, return the locked
1248          * chain.  *ipp is already set w/a ref count and not locked.
1249          *
1250          * (parent is already unlocked).
1251          */
1252         hammer2_inode_unlock_ex(ip, NULL);
1253         *chainp = chain;
1254         if (chain) {
1255                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_INODE);
1256                 /* already locked */
1257                 return (0);
1258         } else {
1259                 return (EIO);
1260         }
1261 }
1262
1263 /*
1264  * Find the directory common to both fdip and tdip, hold and return
1265  * its inode.
1266  */
1267 hammer2_inode_t *
1268 hammer2_inode_common_parent(hammer2_mount_t *hmp,
1269                             hammer2_inode_t *fdip, hammer2_inode_t *tdip)
1270 {
1271         hammer2_inode_t *scan1;
1272         hammer2_inode_t *scan2;
1273
1274         /*
1275          * We used to have a depth field but it complicated matters too
1276          * much for directory renames.  So now its ugly.  Check for
1277          * simple cases before giving up and doing it the expensive way.
1278          *
1279          * XXX need a bottom-up topology stability lock
1280          */
1281         if (fdip == tdip || fdip == tdip->pip) {
1282                 hammer2_inode_ref(fdip);
1283                 return(fdip);
1284         }
1285         if (fdip->pip == tdip) {
1286                 hammer2_inode_ref(tdip);
1287                 return(tdip);
1288         }
1289
1290         /*
1291          * XXX not MPSAFE
1292          */
1293         for (scan1 = fdip; scan1->pmp == fdip->pmp; scan1 = scan1->pip) {
1294                 scan2 = tdip;
1295                 while (scan2->pmp == tdip->pmp) {
1296                         if (scan1 == scan2) {
1297                                 hammer2_inode_ref(scan1);
1298                                 return(scan1);
1299                         }
1300                         scan2 = scan2->pip;
1301                 }
1302         }
1303         panic("hammer2_inode_common_parent: no common parent %p %p\n",
1304               fdip, tdip);
1305         /* NOT REACHED */
1306         return(NULL);
1307 }