sys/vfs/hammer2/hammer2_chain.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 /*
  36  * This subsystem handles direct and indirect block searches, recursions,
  37  * creation, and deletion.  Chains of blockrefs are tracked and modifications
  38  * are flag for propagation... eventually all the way back to the volume
  39  * header.
  40  */
  41
  42 #include <sys/cdefs.h>
  43 #include <sys/cdefs.h>
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/types.h>
  47 #include <sys/lock.h>
  48 #include <sys/uuid.h>
  49
  50 #include "hammer2.h"
  51
  52 SPLAY_GENERATE(hammer2_chain_splay, hammer2_chain, snode, hammer2_chain_cmp);
  53
  54 static int hammer2_indirect_optimize;   /* XXX SYSCTL */
  55
  56 static hammer2_chain_t *hammer2_chain_create_indirect(
  57                         hammer2_mount_t *hmp, hammer2_chain_t *parent,
  58                         hammer2_key_t key, int keybits);
  59
  60 /*
  61  * Compare function for chain splay tree
  62  */
  63 int
  64 hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2)
  65 {
  66         return(chain2->index - chain1->index);
  67 }
  68
  69 /*
  70  * Allocate a new disconnected chain element representing the specified
  71  * bref.  The chain element is locked exclusively and refs is set to 1.
  72  *
  73  * This essentially allocates a system memory structure representing one
  74  * of the media structure types, including inodes.
  75  */
  76 hammer2_chain_t *
  77 hammer2_chain_alloc(hammer2_mount_t *hmp, hammer2_blockref_t *bref)
  78 {
  79         hammer2_chain_t *chain;
  80         hammer2_inode_t *ip;
  81         hammer2_indblock_t *np;
  82         hammer2_data_t *dp;
  83         u_int bytes = 1U << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
  84
  85         /*
  86          * Construct the appropriate system structure.
  87          */
  88         switch(bref->type) {
  89         case HAMMER2_BREF_TYPE_INODE:
  90                 ip = kmalloc(sizeof(*ip), hmp->minode, M_WAITOK | M_ZERO);
  91                 chain = &ip->chain;
  92                 chain->u.ip = ip;
  93                 lockinit(&chain->lk, "inode", 0, LK_CANRECURSE);
  94                 ip->hmp = hmp;
  95                 break;
  96         case HAMMER2_BREF_TYPE_INDIRECT:
  97                 if (bytes == HAMMER2_PBUFSIZE) {
  98                         np = kmalloc(sizeof(*np),
  99                                      hmp->mchain,
 100                                      M_WAITOK | M_ZERO);
 101                         np->is_embedded = 0;
 102                 } else {
 103                         np = kmalloc(offsetof(struct hammer2_indblock,
 104                                               buf[bytes]),
 105                                      hmp->mchain,
 106                                      M_WAITOK | M_ZERO);
 107                         np->is_embedded = 1;
 108                 }
 109                 chain = &np->chain;
 110                 chain->u.np = np;
 111                 lockinit(&chain->lk, "iblk", 0, LK_CANRECURSE);
 112                 break;
 113         case HAMMER2_BREF_TYPE_DATA:
 114                 dp = kmalloc(sizeof(*dp), hmp->mchain, M_WAITOK | M_ZERO);
 115                 chain = &dp->chain;
 116                 chain->u.dp = dp;
 117                 lockinit(&chain->lk, "dblk", 0, LK_CANRECURSE);
 118                 break;
 119         case HAMMER2_BREF_TYPE_VOLUME:
 120                 chain = NULL;
 121                 panic("hammer2_chain_alloc volume type illegal for op");
 122         default:
 123                 chain = NULL;
 124                 panic("hammer2_chain_alloc: unrecognized blockref type: %d",
 125                       bref->type);
 126         }
 127         chain->bref = *bref;
 128         chain->index = -1;      /* not yet assigned */
 129         chain->refs = 1;
 130         chain->bytes = bytes;
 131         lockmgr(&chain->lk, LK_EXCLUSIVE);
 132
 133         return (chain);
 134 }
 135
 136 /*
 137  * Free a disconnected chain element
 138  */
 139 void
 140 hammer2_chain_free(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 141 {
 142         void *mem;
 143
 144         KKASSERT(chain->bp == NULL);
 145         KKASSERT(chain->data == NULL);
 146         KKASSERT(chain->bref.type != HAMMER2_BREF_TYPE_INODE ||
 147                  chain->u.ip->vp == NULL);
 148
 149         if ((mem = chain->u.mem) != NULL) {
 150                 chain->u.mem = NULL;
 151                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
 152                         kfree(mem, hmp->minode);
 153                 else
 154                         kfree(mem, hmp->mchain);
 155         }
 156 }
 157
 158 /*
 159  * Add a reference to a chain element (for shared access).  The chain
 160  * element must already have at least 1 ref controlled by the caller.
 161  */
 162 void
 163 hammer2_chain_ref(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 164 {
 165         KKASSERT(chain->refs > 0);
 166         atomic_add_int(&chain->refs, 1);
 167 }
 168
 169 /*
 170  * Drop the callers reference to the chain element.  If the ref count
 171  * reaches zero the chain element and its related structure (typically an
 172  * inode or indirect block) will be freed and the parent will be
 173  * recursively dropped.
 174  *
 175  * Modified elements hold an additional reference so it should not be
 176  * possible for the count on a modified element to drop to 0.
 177  *
 178  * The chain element must NOT be locked by the caller.
 179  *
 180  * The parent might or might not be locked by the caller but if so it
 181  * will also be referenced so we shouldn't recurse upward.
 182  */
 183 void
 184 hammer2_chain_drop(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 185 {
 186         hammer2_chain_t *parent;
 187         u_int refs;
 188
 189         while (chain) {
 190                 refs = chain->refs;
 191                 cpu_ccfence();
 192                 KKASSERT(refs > 0);
 193                 if (refs == 1) {
 194                         KKASSERT(chain != &hmp->vchain);
 195                         parent = chain->parent;
 196                         if (parent)
 197                                 lockmgr(&parent->lk, LK_EXCLUSIVE);
 198                         if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 199                                 /*
 200                                  * Succeeded, recurse and drop parent
 201                                  */
 202                                 if (!(chain->flags & HAMMER2_CHAIN_DELETED)) {
 203                                         SPLAY_REMOVE(hammer2_chain_splay,
 204                                                      &parent->shead, chain);
 205                                         atomic_set_int(&chain->flags,
 206                                                        HAMMER2_CHAIN_DELETED);
 207                                         /* parent refs dropped via recursion */
 208                                 }
 209                                 chain->parent = NULL;
 210                                 if (parent)
 211                                         lockmgr(&parent->lk, LK_RELEASE);
 212                                 hammer2_chain_free(hmp, chain);
 213                                 chain = parent;
 214                                 /* recurse on parent */
 215                         } else {
 216                                 if (parent)
 217                                         lockmgr(&parent->lk, LK_RELEASE);
 218                                 /* retry the same chain */
 219                         }
 220                 } else {
 221                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1)) {
 222                                 /*
 223                                  * Succeeded, count did not reach zero so
 224                                  * cut out of the loop.
 225                                  */
 226                                 break;
 227                         }
 228                         /* retry the same chain */
 229                 }
 230         }
 231 }
 232
 233 /*
 234  * Lock a chain element, acquiring its data with I/O if necessary.
 235  *
 236  * Returns 0 on success or an error code if the data could not be acquired.
 237  * The chain element is locked either way.
 238  *
 239  * chain->data will be pointed either at the embedded data (e.g. for
 240  * inodes), in which case the buffer cache buffer is released, or will
 241  * point into the bp->b_data buffer with the bp left intact while locked.
 242  */
 243 int
 244 hammer2_chain_lock(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 245 {
 246         hammer2_blockref_t *bref;
 247         hammer2_off_t off_hi;
 248         size_t off_lo;
 249         int error;
 250         void *data;
 251
 252         /*
 253          * Lock the element.  Under certain conditions this might end up
 254          * being a recursive lock.
 255          */
 256         KKASSERT(chain->refs > 0);
 257         lockmgr(&chain->lk, LK_EXCLUSIVE);
 258
 259         /*
 260          * The volume header is a special case
 261          */
 262         if (chain->bref.type == HAMMER2_BREF_TYPE_VOLUME)
 263                 return(0);
 264
 265         /*
 266          * bp must be NULL, so if the data pointer is valid here it points
 267          * to embedded data and no I/O is necessary (whether modified or not).
 268          */
 269         KKASSERT(chain->bp == NULL);
 270         if (chain->data)
 271                 return (0);
 272
 273         /*
 274          * If data is NULL we must issue I/O.  Any error returns the error
 275          * code but leaves the chain locked.
 276          *
 277          * If the chain was modified a new bref will have already been
 278          * allocated and its related bp is probably still sitting in the
 279          * buffer cache.
 280          */
 281         bref = &chain->bref;
 282
 283         off_hi = bref->data_off & HAMMER2_OFF_MASK_HI;
 284         off_lo = (size_t)bref->data_off & HAMMER2_OFF_MASK_LO;
 285         KKASSERT(off_hi != 0);
 286         error = cluster_read(hmp->devvp,
 287                              hmp->voldata.volu_size, off_hi,
 288                              HAMMER2_PBUFSIZE,
 289                              HAMMER2_PBUFSIZE, HAMMER2_PBUFSIZE*8,
 290                              &chain->bp);
 291
 292         /*
 293          * Even though this can be synthesized from bref->data_off we
 294          * store it in the in-memory chain structure for convenience.
 295          */
 296         if (chain->bytes !=
 297             (1U << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX))) {
 298                 panic("hammer2_chain_lock: chain->bytes mismatch");
 299         }
 300
 301         if (error) {
 302                 kprintf("hammer2_chain_get: I/O error %016jx: %d\n",
 303                         (intmax_t)off_hi, error);
 304                 bqrelse(chain->bp);
 305                 chain->bp = NULL;
 306                 return (error);
 307         }
 308
 309         /*
 310          * Setup the data pointer, either pointing it to an embedded data
 311          * structure and copying the data from the buffer, or pointint it
 312          * into the buffer.
 313          *
 314          * The buffer is not retained when copying to an embedded data
 315          * structure in order to avoid potential deadlocks or recursions
 316          * on the same physical buffer.
 317          */
 318         switch (bref->type) {
 319         case HAMMER2_BREF_TYPE_VOLUME:
 320                 /*
 321                  * Copy data from bp to embedded buffer
 322                  */
 323                 KKASSERT(0);    /* not yet - have mount use this soon */
 324                 KKASSERT(off_hi == 0);
 325                 bcopy((char *)chain->bp->b_data + off_lo,
 326                       &hmp->voldata, HAMMER2_PBUFSIZE);
 327                 chain->data = (void *)&hmp->voldata;
 328                 bqrelse(chain->bp);
 329                 chain->bp = NULL;
 330                 break;
 331         case HAMMER2_BREF_TYPE_INODE:
 332                 /*
 333                  * Copy data from bp to embedded buffer.
 334                  */
 335                 bcopy((char *)chain->bp->b_data + off_lo,
 336                       &chain->u.ip->ip_data,
 337                       HAMMER2_INODE_BYTES);
 338                 chain->data = (void *)&chain->u.ip->ip_data;
 339                 bqrelse(chain->bp);
 340                 chain->bp = NULL;
 341                 break;
 342         case HAMMER2_BREF_TYPE_INDIRECT:
 343                 /*
 344                  * Indirect node data may or may not be embedded depending
 345                  * on how much there is.
 346                  */
 347                 if (chain->u.np->is_embedded) {
 348                         bcopy((char *)chain->bp->b_data + off_lo,
 349                               chain->u.np->buf,
 350                               chain->bytes);
 351                         chain->data = (void *)&chain->u.np->buf[0];
 352                         bqrelse(chain->bp);
 353                         chain->bp = NULL;
 354                         break;
 355                 }
 356                 /* fall through */
 357         default:
 358                 /*
 359                  * Leave bp intact
 360                  */
 361                 data = (char *)chain->bp->b_data + off_lo;
 362                 chain->data = data;
 363                 break;
 364         }
 365         return (0);
 366 }
 367
 368 /*
 369  * Resize the chain's physical storage allocation.  Chains can be resized
 370  * smaller without reallocating the storage.  Resizing larger will reallocate
 371  * the storage.
 372  */
 373 void
 374 hammer2_chain_resize(hammer2_mount_t *hmp, hammer2_chain_t *chain, int nradix)
 375 {
 376         hammer2_chain_t *parent;
 377         struct buf *nbp;
 378         size_t obytes;
 379         size_t nbytes;
 380         void *ndata;
 381         int error;
 382
 383         /*
 384          * Only data blocks can be resized for now
 385          */
 386         KKASSERT(chain != &hmp->vchain);
 387         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
 388                  chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT);
 389
 390         /*
 391          * Nothing to do if the element is already the proper size
 392          */
 393         obytes = chain->bytes;
 394         nbytes = 1 << nradix;
 395         if (obytes == nbytes)
 396                 return;
 397
 398         /*
 399          * A deleted inode may still be active but unreachable via sync
 400          * because it has been disconnected from the tree.  Do not allow
 401          * deleted inodes to be marked as being modified because this will
 402          * bump the refs and never get resolved by the sync, leaving the
 403          * inode structure allocated after umount.
 404          */
 405         if ((chain->flags & HAMMER2_CHAIN_DELETED) &&
 406             chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 407                 KKASSERT(chain->data != NULL);
 408                 return;
 409         }
 410
 411         /*
 412          * Set MODIFIED1 and add a chain ref to prevent destruction.  Both
 413          * modified flags share the same ref.
 414          */
 415         atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
 416         if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
 417                 hammer2_chain_ref(hmp, chain);
 418
 419         if (nbytes < obytes) {
 420                 /*
 421                  * If we are making it smaller we don't have to reallocate
 422                  * the block.
 423                  */
 424                 chain->bref.data_off &= ~ HAMMER2_OFF_MASK_RADIX;
 425                 chain->bref.data_off |= (nradix & HAMMER2_OFF_MASK_RADIX);
 426                 chain->bytes = nbytes;
 427         } else {
 428                 /*
 429                  * Otherwise we do
 430                  */
 431                 if (chain != &hmp->vchain) {
 432                         chain->bref.data_off =
 433                           hammer2_freemap_alloc(hmp, chain->bref.type, nbytes);
 434                         chain->bytes = nbytes;
 435                 }
 436                 /* XXX failed allocation */
 437
 438                 switch(chain->bref.type) {
 439                 case HAMMER2_BREF_TYPE_VOLUME:          /* embedded */
 440                 case HAMMER2_BREF_TYPE_INODE:           /* embedded */
 441                         /*
 442                          * data points to embedded structure, no copy needed
 443                          */
 444                         error = 0;
 445                         break;
 446                 case HAMMER2_BREF_TYPE_INDIRECT:
 447                         panic("hammer2_chain_resize: "
 448                               "cannot resize indirect block");
 449                         /* NOT REACHED */
 450                         break;
 451                 case HAMMER2_BREF_TYPE_DATA:
 452                         /*
 453                          * data (if not NULL) points into original bp or
 454                          * to embedded data.  Copy-on-write to new block.
 455                          */
 456                         KKASSERT(chain != &hmp->vchain);        /* safety */
 457                         if (nbytes == HAMMER2_PBUFSIZE) {
 458                                 nbp = getblk(hmp->devvp,
 459                                              chain->bref.data_off &
 460                                               HAMMER2_OFF_MASK_HI,
 461                                              HAMMER2_PBUFSIZE, 0, 0);
 462                                 vfs_bio_clrbuf(nbp);
 463                                 error = 0;
 464                         } else {
 465                                 error = bread(hmp->devvp,
 466                                              chain->bref.data_off &
 467                                               HAMMER2_OFF_MASK_HI,
 468                                              HAMMER2_PBUFSIZE, &nbp);
 469                                 KKASSERT(error == 0);/* XXX handle error */
 470                         }
 471
 472                         /*
 473                          * The new block may be smaller or larger than the
 474                          * old block, only copy what fits.
 475                          */
 476                         ndata = nbp->b_data + (chain->bref.data_off &
 477                                                HAMMER2_OFF_MASK_LO);
 478                         if (chain->data) {
 479                                 if (nbytes < obytes)
 480                                         bcopy(chain->data, ndata, nbytes);
 481                                 else
 482                                         bcopy(chain->data, ndata, obytes);
 483                                 KKASSERT(chain->bp != NULL);
 484                                 bqrelse(chain->bp);
 485                         }
 486                         chain->bp = nbp;
 487                         chain->data = ndata;
 488                         break;
 489                 default:
 490                         panic("hammer2_chain_modify: unknown bref type");
 491                         break;
 492
 493                 }
 494         }
 495
 496         /*
 497          * Recursively mark the parent chain elements so flushes can find
 498          * modified elements.
 499          *
 500          * NOTE: The flush code will modify a SUBMODIFIED-flagged chain
 501          *       during the flush recursion after clearing the parent's
 502          *       SUBMODIFIED bit.  We don't want to re-set the parent's
 503          *       SUBMODIFIED bit in this case!
 504          */
 505         if ((chain->flags & HAMMER2_CHAIN_SUBMODIFIED) == 0) {
 506                 parent = chain->parent;
 507                 while (parent &&
 508                        (parent->flags & HAMMER2_CHAIN_SUBMODIFIED) == 0) {
 509                         atomic_set_int(&parent->flags,
 510                                        HAMMER2_CHAIN_SUBMODIFIED);
 511                         parent = parent->parent;
 512                 }
 513         }
 514 }
 515
 516 /*
 517  * Convert a locked chain that was retrieved read-only to read-write.
 518  *
 519  * If not already marked modified a new physical block will be allocated
 520  * and assigned to the bref.
 521  *
 522  * allocated->modified (without calling hammer2_chain_lock()) results
 523  * in chain->data typically being NULL.  In this situation chain->data
 524  * is assigned and the target area is zero'd out.
 525  *
 526  * If the data is pointing into a bp it will be relocated to a new bp.
 527  * If the data is embedded we leave it alone for now.
 528  */
 529 void
 530 hammer2_chain_modify(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 531 {
 532         hammer2_chain_t *parent;
 533         struct buf *nbp;
 534         void *ndata;
 535         int error;
 536
 537         /*
 538          * Setting the DIRTYBP flag will cause the buffer to be dirtied or
 539          * written-out on unlock.  This bit is independent of the MODIFIED1
 540          * bit because the chain may still need meta-data adjustments done
 541          * by virtue of MODIFIED1 for its parent, and the buffer can be
 542          * flushed out (possibly multiple times) by the OS before that.
 543          */
 544         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DIRTYBP);
 545
 546         /*
 547          * If the chain is already marked MODIFIED1 we can just return.
 548          */
 549         if (chain->flags & HAMMER2_CHAIN_MODIFIED1) {
 550                 KKASSERT(chain->data != NULL);
 551                 return;
 552         }
 553
 554         /*
 555          * A deleted inode may still be active but unreachable via sync
 556          * because it has been disconnected from the tree.  Do not allow
 557          * deleted inodes to be marked as being modified because this will
 558          * bump the refs and never get resolved by the sync, leaving the
 559          * inode structure allocated after umount.
 560          */
 561         if ((chain->flags & HAMMER2_CHAIN_DELETED) &&
 562             chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 563                 KKASSERT(chain->data != NULL);
 564                 return;
 565         }
 566
 567         /*
 568          * Set MODIFIED1 and add a chain ref to prevent destruction.  Both
 569          * modified flags share the same ref.
 570          */
 571         atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
 572         if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
 573                 hammer2_chain_ref(hmp, chain);
 574
 575         /*
 576          * We must allocate the copy-on-write block.
 577          *
 578          * If the data is embedded no other action is required.
 579          *
 580          * If the data is not embedded we acquire and clear the
 581          * new block.  If chain->data is not NULL we then do the
 582          * copy-on-write.  chain->data will then be repointed to the new
 583          * buffer and the old buffer will be released.
 584          *
 585          * For newly created elements with no prior allocation we go
 586          * through the copy-on-write steps except without the copying part.
 587          */
 588         if (chain != &hmp->vchain) {
 589                 if (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)
 590                         kprintf("Replace %d\n", chain->bytes);
 591                 chain->bref.data_off =
 592                     hammer2_freemap_alloc(hmp, chain->bref.type, chain->bytes);
 593                 /* XXX failed allocation */
 594         }
 595
 596         switch(chain->bref.type) {
 597         case HAMMER2_BREF_TYPE_VOLUME:          /* embedded */
 598         case HAMMER2_BREF_TYPE_INODE:           /* embedded */
 599                 /*
 600                  * Inode and Volume data already points to the embedded
 601                  * structure, no copy is needed
 602                  */
 603                 error = 0;
 604                 break;
 605         case HAMMER2_BREF_TYPE_INDIRECT:
 606                 /*
 607                  * If the indirect data is embedded we just leave it
 608                  * in its embedded space, otherwise fall-through to
 609                  * the bp-handling code.
 610                  *
 611                  * If this is a newly allocated block chain->data will
 612                  * be NULL, so make sure it is properly assigned.  In
 613                  * this case the embedded space has already been zero'd
 614                  * by the kmalloc().
 615                  */
 616                 if (chain->u.np->is_embedded) {
 617                         chain->data = (void *)&chain->u.np->buf[0];
 618                         error = 0;
 619                         break;
 620                 }
 621                 /* fallthrough */
 622         case HAMMER2_BREF_TYPE_DATA:
 623                 /*
 624                  * data (if not NULL) points into original bp or to embedded
 625                  * data, copy-on-write to the new block.
 626                  *
 627                  * data (if NULL) indicates that no prior copy exists, the
 628                  * storage must be zero'd.
 629                  */
 630                 KKASSERT(chain != &hmp->vchain);        /* safety */
 631                 if (chain->bytes == HAMMER2_PBUFSIZE) {
 632                         nbp = getblk(hmp->devvp,
 633                                      chain->bref.data_off & HAMMER2_OFF_MASK_HI,
 634                                      HAMMER2_PBUFSIZE, 0, 0);
 635                         /*
 636                          * XXX want to set B_CACHE but not bother to
 637                          * zero because it will be zero'd below?
 638                          */
 639                         vfs_bio_clrbuf(nbp);
 640                         error = 0;
 641                 } else {
 642                         error = bread(hmp->devvp,
 643                                      chain->bref.data_off & HAMMER2_OFF_MASK_HI,
 644                                      HAMMER2_PBUFSIZE, &nbp);
 645                         KKASSERT(error == 0);/* XXX handle error */
 646                 }
 647
 648                 /*
 649                  * Copy or zero-fill on write depending on whether
 650                  * chain->data exists or not.
 651                  */
 652                 ndata = nbp->b_data + (chain->bref.data_off &
 653                                        HAMMER2_OFF_MASK_LO);
 654                 if (chain->data) {
 655                         bcopy(chain->data, ndata, chain->bytes);
 656                         KKASSERT(chain->bp != NULL);
 657                         bqrelse(chain->bp);
 658                 } else {
 659                         bzero(ndata, chain->bytes);
 660                 }
 661                 chain->bp = nbp;
 662                 chain->data = ndata;
 663                 break;
 664         default:
 665                 panic("hammer2_chain_modify: unknown bref type");
 666                 break;
 667
 668         }
 669
 670         /*
 671          * Recursively mark the parent chain elements so flushes can find
 672          * modified elements.
 673          *
 674          * NOTE: The flush code will modify a SUBMODIFIED-flagged chain
 675          *       during the flush recursion after clearing the parent's
 676          *       SUBMODIFIED bit.  We don't want to re-set the parent's
 677          *       SUBMODIFIED bit in this case!
 678          */
 679         if ((chain->flags & HAMMER2_CHAIN_SUBMODIFIED) == 0) {
 680                 parent = chain->parent;
 681                 while (parent &&
 682                        (parent->flags & HAMMER2_CHAIN_SUBMODIFIED) == 0) {
 683                         atomic_set_int(&parent->flags,
 684                                        HAMMER2_CHAIN_SUBMODIFIED);
 685                         parent = parent->parent;
 686                 }
 687         }
 688 }
 689
 690 /*
 691  * Unlock a chain element without dropping its reference count.
 692  * (see hammer2_chain_put() to do both).
 693  *
 694  * Non-embedded data references (chain->bp != NULL) are returned to the
 695  * system and the data field is cleared in that case.  If modified the
 696  * dirty buffer is still returned to the system, can be flushed to disk by
 697  * the system at any time, and will be reconstituted/re-read as needed.
 698  */
 699 void
 700 hammer2_chain_unlock(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 701 {
 702         if (chain->bp) {
 703                 chain->data = NULL;
 704                 if (chain->flags & HAMMER2_CHAIN_DIRTYBP) {
 705                         if (chain->flags & HAMMER2_CHAIN_IOFLUSH) {
 706                                 atomic_clear_int(&chain->flags,
 707                                                  HAMMER2_CHAIN_IOFLUSH);
 708                                 chain->bp->b_flags |= B_RELBUF;
 709                                 bawrite(chain->bp);
 710                         } else {
 711                                 bdwrite(chain->bp);
 712                         }
 713                 } else {
 714                         if (chain->flags & HAMMER2_CHAIN_IOFLUSH) {
 715                                 atomic_clear_int(&chain->flags,
 716                                                  HAMMER2_CHAIN_IOFLUSH);
 717                                 chain->bp->b_flags |= B_RELBUF;
 718                                 brelse(chain->bp);
 719                         } else {
 720                                 /* bp might still be dirty */
 721                                 bqrelse(chain->bp);
 722                         }
 723                 }
 724                 chain->bp = NULL;
 725         }
 726         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DIRTYBP);
 727         lockmgr(&chain->lk, LK_RELEASE);
 728 }
 729
 730 /*
 731  * Locate an in-memory chain.  The parent must be locked.  The in-memory
 732  * chain is returned or NULL if no in-memory chain is present.
 733  *
 734  * NOTE: A chain on-media might exist for this index when NULL is returned.
 735  */
 736 hammer2_chain_t *
 737 hammer2_chain_find(hammer2_mount_t *hmp, hammer2_chain_t *parent, int index)
 738 {
 739         hammer2_chain_t dummy;
 740         hammer2_chain_t *chain;
 741
 742         dummy.index = index;
 743         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead, &dummy);
 744         return (chain);
 745 }
 746
 747 /*
 748  * Return a locked chain structure with all associated data acquired.
 749  *
 750  * Caller must lock the parent on call, the returned child will be locked.
 751  */
 752 hammer2_chain_t *
 753 hammer2_chain_get(hammer2_mount_t *hmp, hammer2_chain_t *parent,
 754                   int index, int flags)
 755 {
 756         hammer2_blockref_t *bref;
 757         hammer2_chain_t *chain;
 758         hammer2_chain_t dummy;
 759
 760         /*
 761          * First see if we have a (possibly modified) chain element cached
 762          * for this (parent, index).  Acquire the data if necessary.
 763          *
 764          * If chain->data is non-NULL the chain should already be marked
 765          * modified.
 766          */
 767         dummy.index = index;
 768         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead, &dummy);
 769         if (chain) {
 770                 hammer2_chain_ref(hmp, chain);
 771                 if ((flags & HAMMER2_LOOKUP_NOLOCK) == 0)
 772                         hammer2_chain_lock(hmp, chain);
 773                 return(chain);
 774         }
 775
 776         /*
 777          * Otherwise lookup the bref and issue I/O (switch on the parent)
 778          */
 779         switch(parent->bref.type) {
 780         case HAMMER2_BREF_TYPE_INODE:
 781                 KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
 782                 bref = &parent->data->ipdata.u.blockset.blockref[index];
 783                 break;
 784         case HAMMER2_BREF_TYPE_INDIRECT:
 785                 KKASSERT(index >= 0 &&
 786                          index < parent->bytes / sizeof(hammer2_blockref_t));
 787                 bref = &parent->data->npdata.blockref[index];
 788                 break;
 789         case HAMMER2_BREF_TYPE_VOLUME:
 790                 KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
 791                 bref = &hmp->voldata.sroot_blockset.blockref[index];
 792                 break;
 793         default:
 794                 bref = NULL;
 795                 panic("hammer2_chain_get: unrecognized blockref type: %d",
 796                       parent->bref.type);
 797         }
 798
 799         /*
 800          * Allocate a chain structure representing the existing media
 801          * entry.  Thus the chain is *not* INITIAL and certainly not
 802          * MODIFIED (yet).
 803          */
 804         chain = hammer2_chain_alloc(hmp, bref);
 805
 806         /*
 807          * Link the chain into its parent.  Caller is expected to hold an
 808          * exclusive lock on the parent.
 809          */
 810         chain->parent = parent;
 811         chain->index = index;
 812         if (SPLAY_INSERT(hammer2_chain_splay, &parent->shead, chain))
 813                 panic("hammer2_chain_link: collision");
 814         KKASSERT(parent->refs > 1);
 815         atomic_add_int(&parent->refs, 1);       /* for splay entry */
 816
 817         /*
 818          * Additional linkage for inodes.  Reuse the parent pointer to
 819          * find the parent directory.
 820          */
 821         if (bref->type == HAMMER2_BREF_TYPE_INODE) {
 822                 while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT)
 823                         parent = parent->parent;
 824                 if (parent->bref.type == HAMMER2_BREF_TYPE_INODE)
 825                         chain->u.ip->pip = parent->u.ip;
 826         }
 827
 828         /*
 829          * Our new chain structure has already been referenced and locked
 830          * but the lock code handles the I/O so call it to resolve the data.
 831          * Then release one of our two exclusive locks.
 832          *
 833          * If NOLOCK is set the release will release the one-and-only lock.
 834          */
 835         if ((flags & HAMMER2_LOOKUP_NOLOCK) == 0)
 836                 hammer2_chain_lock(hmp, chain);
 837         lockmgr(&chain->lk, LK_RELEASE);
 838
 839         return (chain);
 840 }
 841
 842 /*
 843  * Unlock and dereference a chain after use.  It is possible for this to
 844  * recurse up the chain.
 845  */
 846 void
 847 hammer2_chain_put(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 848 {
 849         hammer2_chain_unlock(hmp, chain);
 850         hammer2_chain_drop(hmp, chain);
 851 }
 852
 853 /*
 854  * Locate any key between key_beg and key_end inclusive.  (*parentp)
 855  * typically points to an inode but can also point to a related indirect
 856  * block and this function will recurse upwards and find the inode again.
 857  *
 858  * WARNING!  THIS DOES NOT RETURN KEYS IN LOGICAL KEY ORDER!  ANY KEY
 859  *           WITHIN THE RANGE CAN BE RETURNED.  HOWEVER, AN ITERATION
 860  *           WHICH PICKS UP WHERE WE LEFT OFF WILL CONTINUE THE SCAN.
 861  *
 862  * (*parentp) must be exclusively locked and referenced and can be an inode
 863  * or an existing indirect block within the inode.
 864  *
 865  * On return (*parentp) will be modified to point at the deepest parent chain
 866  * element encountered during the search, as a helper for an insertion or
 867  * deletion.   The new (*parentp) will be locked and referenced and the old
 868  * will be unlocked and dereferenced (no change if they are both the same).
 869  *
 870  * The matching chain will be returned exclusively locked and referenced.
 871  *
 872  * NULL is returned if no match was found, but (*parentp) will still
 873  * potentially be adjusted.
 874  *
 875  * This function will also recurse up the chain if the key is not within the
 876  * current parent's range.  (*parentp) can never be set to NULL.  An iteration
 877  * can simply allow (*parentp) to float inside the loop.
 878  */
 879 hammer2_chain_t *
 880 hammer2_chain_lookup(hammer2_mount_t *hmp, hammer2_chain_t **parentp,
 881                      hammer2_key_t key_beg, hammer2_key_t key_end,
 882                      int flags)
 883 {
 884         hammer2_chain_t *parent;
 885         hammer2_chain_t *chain;
 886         hammer2_chain_t *tmp;
 887         hammer2_blockref_t *base;
 888         hammer2_blockref_t *bref;
 889         hammer2_key_t scan_beg;
 890         hammer2_key_t scan_end;
 891         int count = 0;
 892         int i;
 893
 894         /*
 895          * Recurse (*parentp) upward if necessary until the parent completely
 896          * encloses the key range or we hit the inode.
 897          */
 898         parent = *parentp;
 899         while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
 900                 scan_beg = parent->bref.key;
 901                 scan_end = scan_beg +
 902                            ((hammer2_key_t)1 << parent->bref.keybits) - 1;
 903                 if (key_beg >= scan_beg && key_end <= scan_end)
 904                         break;
 905                 hammer2_chain_unlock(hmp, parent);
 906                 parent = parent->parent;
 907                 hammer2_chain_ref(hmp, parent);         /* ref new parent */
 908                 hammer2_chain_lock(hmp, parent);        /* lock new parent */
 909                 hammer2_chain_drop(hmp, *parentp);      /* drop old parent */
 910                 *parentp = parent;                      /* new parent */
 911         }
 912
 913 again:
 914         /*
 915          * Locate the blockref array.  Currently we do a fully associative
 916          * search through the array.
 917          */
 918         switch(parent->bref.type) {
 919         case HAMMER2_BREF_TYPE_INODE:
 920                 /*
 921                  * Special shortcut for embedded data returns the inode
 922                  * itself.  Callers must detect this condition and access
 923                  * the embedded data (the strategy code does this for us).
 924                  *
 925                  * This is only applicable to regular files and softlinks.
 926                  */
 927                 if (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
 928                         hammer2_chain_ref(hmp, parent);
 929                         if ((flags & HAMMER2_LOOKUP_NOLOCK) == 0)
 930                                 hammer2_chain_lock(hmp, parent);
 931                         return (parent);
 932                 }
 933                 base = &parent->data->ipdata.u.blockset.blockref[0];
 934                 count = HAMMER2_SET_COUNT;
 935                 break;
 936         case HAMMER2_BREF_TYPE_INDIRECT:
 937                 if (parent->data == NULL)
 938                         panic("parent->data is NULL");
 939                 base = &parent->data->npdata.blockref[0];
 940                 count = parent->bytes / sizeof(hammer2_blockref_t);
 941                 break;
 942         case HAMMER2_BREF_TYPE_VOLUME:
 943                 base = &hmp->voldata.sroot_blockset.blockref[0];
 944                 count = HAMMER2_SET_COUNT;
 945                 break;
 946         default:
 947                 panic("hammer2_chain_lookup: unrecognized blockref type: %d",
 948                       parent->bref.type);
 949                 base = NULL;    /* safety */
 950                 count = 0;      /* safety */
 951         }
 952
 953         /*
 954          * If the element and key overlap we use the element.
 955          */
 956         bref = NULL;
 957         for (i = 0; i < count; ++i) {
 958                 tmp = hammer2_chain_find(hmp, parent, i);
 959                 bref = (tmp) ? &tmp->bref : &base[i];
 960                 if (bref->type == 0)
 961                         continue;
 962                 scan_beg = bref->key;
 963                 scan_end = scan_beg + ((hammer2_key_t)1 << bref->keybits) - 1;
 964                 if (key_beg <= scan_end && key_end >= scan_beg)
 965                         break;
 966         }
 967         if (i == count) {
 968                 if (key_beg == key_end)
 969                         return (NULL);
 970                 return (hammer2_chain_next(hmp, parentp, NULL,
 971                                            key_beg, key_end, flags));
 972         }
 973
 974         /*
 975          * Acquire the new chain element.  If the chain element is an
 976          * indirect block we must search recursively.
 977          */
 978         chain = hammer2_chain_get(hmp, parent, i, flags);
 979         if (chain == NULL)
 980                 return (NULL);
 981
 982         /*
 983          * If the chain element is an indirect block it becomes the new
 984          * parent and we loop on it.  We must fixup the chain we loop on
 985          * if the caller passed flags to us that aren't sufficient for our
 986          * needs.
 987          */
 988         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
 989                 hammer2_chain_put(hmp, parent);
 990                 *parentp = parent = chain;
 991                 if (flags & HAMMER2_LOOKUP_NOLOCK)
 992                         hammer2_chain_lock(hmp, chain);
 993                 goto again;
 994         }
 995
 996         /*
 997          * All done, return chain
 998          */
 999         return (chain);
1000 }
1001
1002 /*
1003  * After having issued a lookup we can iterate all matching keys.
1004  *
1005  * If chain is non-NULL we continue the iteration from just after it's index.
1006  *
1007  * If chain is NULL we assume the parent was exhausted and continue the
1008  * iteration at the next parent.
1009  */
1010 hammer2_chain_t *
1011 hammer2_chain_next(hammer2_mount_t *hmp, hammer2_chain_t **parentp,
1012                    hammer2_chain_t *chain,
1013                    hammer2_key_t key_beg, hammer2_key_t key_end,
1014                    int flags)
1015 {
1016         hammer2_chain_t *parent;
1017         hammer2_chain_t *tmp;
1018         hammer2_blockref_t *base;
1019         hammer2_blockref_t *bref;
1020         hammer2_key_t scan_beg;
1021         hammer2_key_t scan_end;
1022         int i;
1023         int count;
1024
1025         parent = *parentp;
1026
1027 again:
1028         /*
1029          * Calculate the next index and recalculate the parent if necessary.
1030          */
1031         if (chain) {
1032                 /*
1033                  * Continue iteration within current parent.  If not NULL
1034                  * the passed-in chain may or may not be locked, based on
1035                  * the LOOKUP_NOLOCK flag (passed in as returned from lookup
1036                  * or a prior next).
1037                  */
1038                 i = chain->index + 1;
1039                 if (flags & HAMMER2_LOOKUP_NOLOCK)
1040                         hammer2_chain_drop(hmp, chain);
1041                 else
1042                         hammer2_chain_put(hmp, chain);
1043
1044                 /*
1045                  * Any scan where the lookup returned degenerate data embedded
1046                  * in the inode has an invalid index and must terminate.
1047                  */
1048                 if (chain == parent)
1049                         return(NULL);
1050                 chain = NULL;
1051         } else if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT) {
1052                 /*
1053                  * We reached the end of the iteration.
1054                  */
1055                 return (NULL);
1056         } else {
1057                 /*
1058                  * Continue iteration with next parent unless the current
1059                  * parent covers the range.
1060                  */
1061                 hammer2_chain_t *nparent;
1062
1063                 if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT)
1064                         return (NULL);
1065
1066                 scan_beg = parent->bref.key;
1067                 scan_end = scan_beg +
1068                             ((hammer2_key_t)1 << parent->bref.keybits) - 1;
1069                 if (key_beg >= scan_beg && key_end <= scan_end)
1070                         return (NULL);
1071
1072                 i = parent->index + 1;
1073                 nparent = parent->parent;
1074                 hammer2_chain_ref(hmp, nparent);        /* ref new parent */
1075                 hammer2_chain_unlock(hmp, parent);
1076                 hammer2_chain_lock(hmp, nparent);       /* lock new parent */
1077                 hammer2_chain_drop(hmp, parent);        /* drop old parent */
1078                 *parentp = parent = nparent;
1079         }
1080
1081 again2:
1082         /*
1083          * Locate the blockref array.  Currently we do a fully associative
1084          * search through the array.
1085          */
1086         switch(parent->bref.type) {
1087         case HAMMER2_BREF_TYPE_INODE:
1088                 base = &parent->data->ipdata.u.blockset.blockref[0];
1089                 count = HAMMER2_SET_COUNT;
1090                 break;
1091         case HAMMER2_BREF_TYPE_INDIRECT:
1092                 base = &parent->data->npdata.blockref[0];
1093                 count = parent->bytes / sizeof(hammer2_blockref_t);
1094                 break;
1095         case HAMMER2_BREF_TYPE_VOLUME:
1096                 base = &hmp->voldata.sroot_blockset.blockref[0];
1097                 count = HAMMER2_SET_COUNT;
1098                 break;
1099         default:
1100                 panic("hammer2_chain_next: unrecognized blockref type: %d",
1101                       parent->bref.type);
1102                 base = NULL;    /* safety */
1103                 count = 0;      /* safety */
1104                 break;
1105         }
1106         KKASSERT(i <= count);
1107
1108         /*
1109          * Look for the key.  If we are unable to find a match and an exact
1110          * match was requested we return NULL.  If a range was requested we
1111          * run hammer2_chain_next() to iterate.
1112          */
1113         bref = NULL;
1114         while (i < count) {
1115                 tmp = hammer2_chain_find(hmp, parent, i);
1116                 bref = (tmp) ? &tmp->bref : &base[i];
1117                 if (bref->type == 0) {
1118                         ++i;
1119                         continue;
1120                 }
1121                 scan_beg = bref->key;
1122                 scan_end = scan_beg + ((hammer2_key_t)1 << bref->keybits) - 1;
1123                 if (key_beg <= scan_end && key_end >= scan_beg)
1124                         break;
1125                 ++i;
1126         }
1127
1128         /*
1129          * If we couldn't find a match recurse up a parent to continue the
1130          * search.
1131          */
1132         if (i == count)
1133                 goto again;
1134
1135         /*
1136          * Acquire the new chain element.  If the chain element is an
1137          * indirect block we must search recursively.
1138          */
1139         chain = hammer2_chain_get(hmp, parent, i, flags);
1140         if (chain == NULL)
1141                 return (NULL);
1142
1143         /*
1144          * If the chain element is an indirect block it becomes the new
1145          * parent and we loop on it.  We may have to lock the chain when
1146          * cycling it in as the new parent as it will not be locked if the
1147          * caller passed NOLOCK.
1148          */
1149         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
1150                 hammer2_chain_put(hmp, parent);
1151                 *parentp = parent = chain;
1152                 if (flags & HAMMER2_LOOKUP_NOLOCK)
1153                         hammer2_chain_lock(hmp, chain);
1154                 i = 0;
1155                 goto again2;
1156         }
1157
1158         /*
1159          * All done, return chain
1160          */
1161         return (chain);
1162 }
1163
1164 /*
1165  * Create and return a new hammer2 system memory structure of the specified
1166  * key, type and size and insert it RELATIVE TO (PARENT).
1167  *
1168  * (parent) is typically either an inode or an indirect  block, acquired
1169  * acquired as a side effect of issuing a prior failed lookup.  parent
1170  * must be locked and held.  Do not pass the inode chain to this function
1171  * unless that is the chain returned by the failed lookup.
1172  *
1173  * Non-indirect types will automatically allocate indirect blocks as required
1174  * if the new item does not fit in the current (parent).
1175  *
1176  * Indirect types will move a portion of the existing blockref array in
1177  * (parent) into the new indirect type and then use one of the free slots
1178  * to emplace the new indirect type.
1179  *
1180  * A new locked, referenced chain element is returned of the specified type.
1181  * This element will also be marked as modified and contain a data area
1182  * ready for initialization.
1183  */
1184 hammer2_chain_t *
1185 hammer2_chain_create(hammer2_mount_t *hmp, hammer2_chain_t *parent,
1186                      hammer2_chain_t *chain,
1187                      hammer2_key_t key, int keybits, int type, size_t bytes)
1188 {
1189         hammer2_blockref_t dummy;
1190         hammer2_blockref_t *base;
1191         hammer2_blockref_t *bref;
1192         hammer2_chain_t dummy_chain;
1193         int unlock_parent = 0;
1194         int allocated = 0;
1195         int count;
1196         int i;
1197
1198         if (chain == NULL) {
1199                 /*
1200                  * First allocate media space and construct the dummy bref,
1201                  * then allocate the in-memory chain structure.
1202                  */
1203                 bzero(&dummy, sizeof(dummy));
1204                 dummy.type = type;
1205                 dummy.key = key;
1206                 dummy.keybits = keybits;
1207                 dummy.data_off = hammer2_bytes_to_radix(bytes);
1208                 chain = hammer2_chain_alloc(hmp, &dummy);
1209                 allocated = 1;
1210
1211                 /*
1212                  * We set the WAS_MODIFIED flag here so the chain gets
1213                  * marked as modified below.
1214                  */
1215                 chain->flags |= HAMMER2_CHAIN_INITIAL |
1216                                 HAMMER2_CHAIN_WAS_MODIFIED;
1217
1218                 /*
1219                  * Recalculate bytes to reflect the actual media block
1220                  * allocation.
1221                  */
1222                 bytes = (hammer2_off_t)1 <<
1223                         (int)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
1224                 chain->bytes = bytes;
1225
1226                 switch(type) {
1227                 case HAMMER2_BREF_TYPE_VOLUME:
1228                         panic("hammer2_chain_create: called with volume type");
1229                         break;
1230                 case HAMMER2_BREF_TYPE_INODE:
1231                         KKASSERT(bytes == HAMMER2_INODE_BYTES);
1232                         chain->data = (void *)&chain->u.ip->ip_data;
1233                         break;
1234                 case HAMMER2_BREF_TYPE_INDIRECT:
1235                         /*
1236                          * May or may not be embedded (chain->data may or
1237                          * may not be NULL)
1238                          */
1239                         if (chain->u.np->is_embedded) {
1240                                 chain->data = (void *)&chain->u.np->buf[0];
1241                         } else {
1242                                 KKASSERT(chain->data == NULL);
1243                         }
1244                         break;
1245                 default:
1246                         /* leave chain->data NULL */
1247                         KKASSERT(chain->data == NULL);
1248                         break;
1249                 }
1250         } else {
1251                 /*
1252                  * Potentially update the chain's key/keybits, but it will
1253                  * only be marked modified if WAS_MODIFIED is set (if it
1254                  * was modified at the time of its removal during a rename).
1255                  */
1256                 chain->bref.key = key;
1257                 chain->bref.keybits = keybits;
1258         }
1259
1260 again:
1261         /*
1262          * Locate a free blockref in the parent's array
1263          */
1264         switch(parent->bref.type) {
1265         case HAMMER2_BREF_TYPE_INODE:
1266                 KKASSERT(parent->data != NULL);
1267                 base = &parent->data->ipdata.u.blockset.blockref[0];
1268                 count = HAMMER2_SET_COUNT;
1269                 break;
1270         case HAMMER2_BREF_TYPE_INDIRECT:
1271                 KKASSERT(parent->data != NULL);
1272                 base = &parent->data->npdata.blockref[0];
1273                 count = parent->bytes / sizeof(hammer2_blockref_t);
1274                 break;
1275         case HAMMER2_BREF_TYPE_VOLUME:
1276                 KKASSERT(parent->data != NULL);
1277                 base = &hmp->voldata.sroot_blockset.blockref[0];
1278                 count = HAMMER2_SET_COUNT;
1279                 break;
1280         default:
1281                 panic("hammer2_chain_create: unrecognized blockref type: %d",
1282                       parent->bref.type);
1283                 count = 0;
1284                 break;
1285         }
1286
1287         /*
1288          * Scan for an unallocated bref, also skipping any slots occupied
1289          * by in-memory chain elements that may not yet have been updated
1290          * in the parent's bref array.
1291          */
1292         bzero(&dummy_chain, sizeof(dummy_chain));
1293         bref = NULL;
1294         for (i = 0; i < count; ++i) {
1295                 bref = &base[i];
1296                 dummy_chain.index = i;
1297                 if (bref->type == 0 &&
1298                     SPLAY_FIND(hammer2_chain_splay,
1299                                &parent->shead, &dummy_chain) == NULL) {
1300                         break;
1301                 }
1302         }
1303
1304         /*
1305          * If no free blockref count be found we must create an indirect
1306          * block and move a number of blockrefs into it.  With the parent
1307          * locked we can safely lock each child in order to move it without
1308          * causing a deadlock.
1309          *
1310          * This may return the new indirect block or the old parent depending
1311          * on where the key falls.
1312          */
1313         if (i == count) {
1314                 hammer2_chain_t *nparent;
1315
1316                 nparent = hammer2_chain_create_indirect(hmp, parent,
1317                                                         key, keybits);
1318                 if (nparent == NULL) {
1319                         if (allocated)
1320                                 hammer2_chain_free(hmp, chain);
1321                         chain = NULL;
1322                         goto done;
1323                 }
1324                 if (parent != nparent) {
1325                         if (unlock_parent)
1326                                 hammer2_chain_put(hmp, parent);
1327                         parent = nparent;
1328                         unlock_parent = 1;
1329                 }
1330                 goto again;
1331         }
1332
1333         /*
1334          * Link the chain into its parent.
1335          */
1336         if (chain->parent != NULL)
1337                 panic("hammer2: hammer2_chain_create: chain already connected");
1338         KKASSERT(chain->parent == NULL);
1339         chain->parent = parent;
1340         chain->index = i;
1341         if (SPLAY_INSERT(hammer2_chain_splay, &parent->shead, chain))
1342                 panic("hammer2_chain_link: collision");
1343         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DELETED);
1344         KKASSERT(parent->refs > 1);
1345         atomic_add_int(&parent->refs, 1);
1346
1347         /*
1348          * Additional linkage for inodes.  Reuse the parent pointer to
1349          * find the parent directory.
1350          */
1351         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1352                 hammer2_chain_t *scan = parent;
1353                 while (scan->bref.type == HAMMER2_BREF_TYPE_INDIRECT)
1354                         scan = scan->parent;
1355                 if (scan->bref.type == HAMMER2_BREF_TYPE_INODE)
1356                         chain->u.ip->pip = scan->u.ip;
1357         }
1358
1359         /*
1360          * Mark the newly created or previously disconnected chain element
1361          * as modified and fully resolve the chain->data pointer.  The
1362          * WAS_MODIFIED bit will be set in both cases.
1363          *
1364          * Chain elements with embedded data will not issue I/O at this time.
1365          * A new block will be allocated for the buffer but not instantiated.
1366          *
1367          * Chain elements which do not use embedded data will allocate
1368          * the new block AND instantiate its buffer cache buffer, pointing
1369          * the data at the bp.
1370          */
1371         if (chain->flags & HAMMER2_CHAIN_WAS_MODIFIED) {
1372                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_WAS_MODIFIED);
1373                 hammer2_chain_modify(hmp, chain);
1374         }
1375
1376 done:
1377         if (unlock_parent)
1378                 hammer2_chain_put(hmp, parent);
1379         return (chain);
1380 }
1381
1382 /*
1383  * Create an indirect block that covers one or more of the elements in the
1384  * current parent.  Either returns the existing parent with no locking or
1385  * ref changes or returns the new indirect block locked and referenced,
1386  * depending on what the specified key falls into.
1387  *
1388  * The key/keybits for the indirect mode only needs to follow three rules:
1389  *
1390  * (1) That all elements underneath it fit within its key space and
1391  *
1392  * (2) That all elements outside it are outside its key space.
1393  *
1394  * (3) When creating the new indirect block any elements in the current
1395  *     parent that fit within the new indirect block's keyspace must be
1396  *     moved into the new indirect block.
1397  *
1398  * (4) The keyspace chosen for the inserted indirect block CAN cover a wider
1399  *     keyspace the the current parent, but lookup/iteration rules will
1400  *     ensure (and must ensure) that rule (2) for all parents leading up
1401  *     to the nearest inode or the root volume header is adhered to.  This
1402  *     is accomplished by always recursing through matching keyspaces in
1403  *     the hammer2_chain_lookup() and hammer2_chain_next() API.
1404  *
1405  * The current implementation calculates the current worst-case keyspace by
1406  * iterating the current parent and then divides it into two halves, choosing
1407  * whichever half has the most elements (not necessarily the half containing
1408  * the requested key).
1409  *
1410  * We can also opt to use the half with the least number of elements.  This
1411  * causes lower-numbered keys (aka logical file offsets) to recurse through
1412  * fewer indirect blocks and higher-numbered keys to recurse through more.
1413  * This also has the risk of not moving enough elements to the new indirect
1414  * block and being forced to create several indirect blocks before the element
1415  * can be inserted.
1416  */
1417 static
1418 hammer2_chain_t *
1419 hammer2_chain_create_indirect(hammer2_mount_t *hmp, hammer2_chain_t *parent,
1420                               hammer2_key_t create_key, int create_bits)
1421 {
1422         hammer2_blockref_t *base;
1423         hammer2_blockref_t *bref;
1424         hammer2_chain_t *chain;
1425         hammer2_chain_t *ichain;
1426         hammer2_chain_t dummy;
1427         hammer2_key_t key = create_key;
1428         int keybits = create_bits;
1429         int locount = 0;
1430         int hicount = 0;
1431         int count;
1432         int nbytes;
1433         int i;
1434
1435         /*
1436          * Mark the parent modified so our base[] pointer remains valid
1437          * while we move entries.
1438          */
1439         hammer2_chain_modify(hmp, parent);
1440
1441         /*
1442          * Locate a free blockref in the parent's array
1443          */
1444         switch(parent->bref.type) {
1445         case HAMMER2_BREF_TYPE_INODE:
1446                 base = &parent->data->ipdata.u.blockset.blockref[0];
1447                 count = HAMMER2_SET_COUNT;
1448                 break;
1449         case HAMMER2_BREF_TYPE_INDIRECT:
1450                 base = &parent->data->npdata.blockref[0];
1451                 count = parent->bytes / sizeof(hammer2_blockref_t);
1452                 break;
1453         case HAMMER2_BREF_TYPE_VOLUME:
1454                 base = &hmp->voldata.sroot_blockset.blockref[0];
1455                 count = HAMMER2_SET_COUNT;
1456                 break;
1457         default:
1458                 panic("hammer2_chain_create_indirect: "
1459                       "unrecognized blockref type: %d",
1460                       parent->bref.type);
1461                 count = 0;
1462                 break;
1463         }
1464
1465         /*
1466          * Scan for an unallocated bref, also skipping any slots occupied
1467          * by in-memory chain elements that may not yet have been updated
1468          * in the parent's bref array.
1469          */
1470         bzero(&dummy, sizeof(dummy));
1471         for (i = 0; i < count; ++i) {
1472                 int nkeybits;
1473
1474                 bref = &base[i];
1475                 if (bref->type == 0) {
1476                         dummy.index = i;
1477                         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead,
1478                                            &dummy);
1479                         if (chain == NULL)
1480                                 continue;
1481                         bref = &chain->bref;
1482                 }
1483
1484                 /*
1485                  * Expand our calculated key range (key, keybits) to fit
1486                  * the scanned key.  nkeybits represents the full range
1487                  * that we will later cut in half (two halves @ nkeybits - 1).
1488                  */
1489                 nkeybits = keybits;
1490                 if (nkeybits < bref->keybits)
1491                         nkeybits = bref->keybits;
1492                 while ((~(((hammer2_key_t)1 << nkeybits) - 1) &
1493                         (key ^ bref->key)) != 0) {
1494                         ++nkeybits;
1495                 }
1496
1497                 /*
1498                  * If the new key range is larger we have to determine
1499                  * which side of the new key range the existing keys fall
1500                  * under by checking the high bit, then collapsing the
1501                  * locount into the hicount or vise-versa.
1502                  */
1503                 if (keybits != nkeybits) {
1504                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
1505                                 hicount += locount;
1506                                 locount = 0;
1507                         } else {
1508                                 locount += hicount;
1509                                 hicount = 0;
1510                         }
1511                         keybits = nkeybits;
1512                 }
1513
1514                 /*
1515                  * The newly scanned key will be in the lower half or the
1516                  * higher half of the (new) key range.
1517                  */
1518                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
1519                         ++hicount;
1520                 else
1521                         ++locount;
1522         }
1523
1524         /*
1525          * Adjust keybits to represent half of the full range calculated
1526          * above.
1527          */
1528         --keybits;
1529
1530         /*
1531          * Select whichever half contains the most elements.  Theoretically
1532          * we can select either side as long as it contains at least one
1533          * element (in order to ensure that a free slot is present to hold
1534          * the indirect block).
1535          */
1536         key &= ~(((hammer2_key_t)1 << keybits) - 1);
1537         if (hammer2_indirect_optimize) {
1538                 /*
1539                  * Insert node for least number of keys, this will arrange
1540                  * the first few blocks of a large file or the first few
1541                  * inodes in a directory with fewer indirect blocks when
1542                  * created linearly.
1543                  */
1544                 if (hicount < locount && hicount != 0)
1545                         key |= (hammer2_key_t)1 << keybits;
1546                 else
1547                         key &= ~(hammer2_key_t)1 << keybits;
1548         } else {
1549                 /*
1550                  * Insert node for most number of keys, best for heavily
1551                  * fragmented files.
1552                  */
1553                 if (hicount > locount)
1554                         key |= (hammer2_key_t)1 << keybits;
1555                 else
1556                         key &= ~(hammer2_key_t)1 << keybits;
1557         }
1558
1559         /*
1560          * How big should our new indirect block be?  It has to be at least
1561          * as large as its parent.
1562          */
1563         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE)
1564                 nbytes = HAMMER2_IND_BYTES_MIN;
1565         else
1566                 nbytes = HAMMER2_IND_BYTES_MAX;
1567         if (nbytes < count * sizeof(hammer2_blockref_t))
1568                 nbytes = count * sizeof(hammer2_blockref_t);
1569
1570         /*
1571          * Ok, create our new indirect block
1572          */
1573         dummy.bref.type = HAMMER2_BREF_TYPE_INDIRECT;
1574         dummy.bref.key = key;
1575         dummy.bref.keybits = keybits;
1576         dummy.bref.data_off = hammer2_bytes_to_radix(nbytes);
1577         ichain = hammer2_chain_alloc(hmp, &dummy.bref);
1578         ichain->flags |= HAMMER2_CHAIN_INITIAL;
1579
1580         /*
1581          * Iterate the original parent and move the matching brefs into
1582          * the new indirect block.
1583          */
1584         for (i = 0; i < count; ++i) {
1585                 /*
1586                  * For keying purposes access the bref from the media or
1587                  * from our in-memory cache.  In cases where the in-memory
1588                  * cache overrides the media the keyrefs will be the same
1589                  * anyway so we can avoid checking the cache when the media
1590                  * has a key.
1591                  */
1592                 bref = &base[i];
1593                 if (bref->type == 0) {
1594                         dummy.index = i;
1595                         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead,
1596                                            &dummy);
1597                         if (chain == NULL) {
1598                                 /*
1599                                  * Select index indirect block is placed in
1600                                  */
1601                                 if (ichain->index < 0)
1602                                         ichain->index = i;
1603                                 continue;
1604                         }
1605                         bref = &chain->bref;
1606                 }
1607
1608                 /*
1609                  * Skip keys not in the chosen half (low or high), only bit
1610                  * (keybits - 1) needs to be compared but for safety we
1611                  * will compare all msb bits plus that bit again.
1612                  */
1613                 if ((~(((hammer2_key_t)1 << keybits) - 1) &
1614                     (key ^ bref->key)) != 0) {
1615                         continue;
1616                 }
1617
1618                 /*
1619                  * This element is being moved, its slot is available
1620                  * for our indirect block.
1621                  */
1622                 if (ichain->index < 0)
1623                         ichain->index = i;
1624
1625                 /*
1626                  * Load the new indirect block by acquiring or allocating
1627                  * the related chain entries, then simply move it to the
1628                  * new parent (ichain).
1629                  *
1630                  * Flagging the new chain entry MOVED will cause a flush
1631                  * to synchronize its block into the new indirect block.
1632                  * The chain is unlocked after being moved but needs to
1633                  * retain a reference for the MOVED state
1634                  *
1635                  * We must still set SUBMODIFIED in the parent but we do
1636                  * that after the loop.
1637                  *
1638                  * XXX we really need a lock here but we don't need the
1639                  *     data.  NODATA feature needed.
1640                  */
1641                 chain = hammer2_chain_get(hmp, parent, i,
1642                                           HAMMER2_LOOKUP_NOLOCK);
1643                 SPLAY_REMOVE(hammer2_chain_splay, &parent->shead, chain);
1644                 if (SPLAY_INSERT(hammer2_chain_splay, &ichain->shead, chain))
1645                         panic("hammer2_chain_create_indirect: collision");
1646                 chain->parent = ichain;
1647                 bzero(&base[i], sizeof(base[i]));
1648                 atomic_add_int(&parent->refs, -1);
1649                 atomic_add_int(&ichain->refs, 1);
1650                 if (chain->flags & HAMMER2_CHAIN_MOVED) {
1651                         /* We don't need the ref from the chain_get */
1652                         hammer2_chain_drop(hmp, chain);
1653                 } else {
1654                         /* MOVED bit inherits the ref from the chain_get */
1655                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_MOVED);
1656                 }
1657                 KKASSERT(parent->refs > 0);
1658                 chain = NULL;
1659         }
1660
1661         /*
1662          * Insert the new indirect block into the parent now that we've
1663          * cleared out some entries in the parent.  We calculated a good
1664          * insertion index in the loop above (ichain->index).
1665          */
1666         KKASSERT(ichain->index >= 0);
1667         if (SPLAY_INSERT(hammer2_chain_splay, &parent->shead, ichain))
1668                 panic("hammer2_chain_create_indirect: ichain insertion");
1669         ichain->parent = parent;
1670         atomic_add_int(&parent->refs, 1);
1671
1672         /*
1673          * Mark the new indirect block modified after insertion, which
1674          * will propagate up through parent all the way to the root and
1675          * also allocate the physical block in ichain for our caller,
1676          * and assign ichain->data to a pre-zero'd space (because there
1677          * is not prior data to copy into it).
1678          *
1679          * We have to set SUBMODIFIED in ichain's flags manually so the
1680          * flusher knows it has to recurse through it to get to all of
1681          * our moved blocks.
1682          */
1683         hammer2_chain_modify(hmp, ichain);
1684         atomic_set_int(&ichain->flags, HAMMER2_CHAIN_SUBMODIFIED);
1685
1686         /*
1687          * Figure out what to return.
1688          */
1689         if (create_bits >= keybits) {
1690                 /*
1691                  * Key being created is way outside the key range,
1692                  * return the original parent.
1693                  */
1694                 hammer2_chain_put(hmp, ichain);
1695         } else if (~(((hammer2_key_t)1 << keybits) - 1) &
1696                    (create_key ^ key)) {
1697                 /*
1698                  * Key being created is outside the key range,
1699                  * return the original parent.
1700                  */
1701                 hammer2_chain_put(hmp, ichain);
1702         } else {
1703                 /*
1704                  * Otherwise its in the range, return the new parent.
1705                  */
1706                 parent = ichain;
1707         }
1708
1709         return(parent);
1710 }
1711
1712 /*
1713  * Physically delete the specified chain element.  Note that inodes with
1714  * open descriptors should not be deleted (as with other filesystems) until
1715  * the last open descriptor is closed.
1716  *
1717  * This routine will remove the chain element from its parent and potentially
1718  * also recurse upward and delete indirect blocks which become empty as a
1719  * side effect.
1720  *
1721  * The caller must pass a pointer to the chain's parent, also locked and
1722  * referenced.  (*parentp) will be modified in a manner similar to a lookup
1723  * or iteration when indirect blocks are also deleted as a side effect.
1724  */
1725 void
1726 hammer2_chain_delete(hammer2_mount_t *hmp, hammer2_chain_t *parent,
1727                      hammer2_chain_t *chain)
1728 {
1729         hammer2_blockref_t *base;
1730         int count;
1731
1732         if (chain->parent != parent)
1733                 panic("hammer2_chain_delete: parent mismatch");
1734
1735         /*
1736          * Mark the parent modified so our base[] pointer remains valid
1737          * while we move entries.
1738          *
1739          * Calculate the blockref reference in the parent
1740          */
1741         hammer2_chain_modify(hmp, parent);
1742
1743         switch(parent->bref.type) {
1744         case HAMMER2_BREF_TYPE_INODE:
1745                 base = &parent->data->ipdata.u.blockset.blockref[0];
1746                 count = HAMMER2_SET_COUNT;
1747                 break;
1748         case HAMMER2_BREF_TYPE_INDIRECT:
1749                 base = &parent->data->npdata.blockref[0];
1750                 count = parent->bytes / sizeof(hammer2_blockref_t);
1751                 break;
1752         case HAMMER2_BREF_TYPE_VOLUME:
1753                 base = &hmp->voldata.sroot_blockset.blockref[0];
1754                 count = HAMMER2_SET_COUNT;
1755                 break;
1756         default:
1757                 panic("hammer2_chain_delete: unrecognized blockref type: %d",
1758                       parent->bref.type);
1759                 count = 0;
1760                 break;
1761         }
1762
1763         /*
1764          * Disconnect the bref in the parent, remove the chain, and
1765          * disconnect in-memory fields from the parent.
1766          */
1767         KKASSERT(chain->index >= 0 && chain->index < count);
1768         base += chain->index;
1769         bzero(base, sizeof(*base));
1770
1771         SPLAY_REMOVE(hammer2_chain_splay, &parent->shead, chain);
1772         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
1773         atomic_add_int(&parent->refs, -1);      /* for splay entry */
1774         chain->index = -1;
1775
1776         chain->parent = NULL;
1777         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
1778                 chain->u.ip->pip = NULL;
1779
1780         /*
1781          * Nobody references the underlying object any more so we can
1782          * clear any pending modification(s) on it.  This can theoretically
1783          * recurse downward but even just clearing the bit on this item
1784          * will effectively recurse if someone is doing a rm -rf and greatly
1785          * reduce the I/O required.
1786          *
1787          * The MODIFIED1 bit is cleared but we have to remember the old state
1788          * in case this deletion is related to a rename.  The ref on the
1789          * chain is shared by both modified flags.
1790          */
1791         if (chain->flags & HAMMER2_CHAIN_MODIFIED1) {
1792                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
1793                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_WAS_MODIFIED);
1794                 if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
1795                         hammer2_chain_drop(hmp, chain);
1796         }
1797 }
1798
1799 /*
1800  * Recursively flush the specified chain.  The chain is locked and
1801  * referenced by the caller and will remain so on return.
1802  *
1803  * This cannot be called with the volume header's vchain (yet).
1804  *
1805  * PASS1 - clear the MODIFIED1 bit (and set the MODIFIED2 bit XXX)
1806  *
1807  */
1808 static void
1809 hammer2_chain_flush_pass1(hammer2_mount_t *hmp, hammer2_chain_t *chain)
1810 {
1811         /*
1812          * Flush any children of this chain entry.
1813          */
1814         if (chain->flags & HAMMER2_CHAIN_SUBMODIFIED) {
1815                 hammer2_blockref_t *base;
1816                 hammer2_chain_t *scan;
1817                 hammer2_chain_t *next;
1818                 int count;
1819                 int submodified = 0;
1820
1821                 /*
1822                  * Modifications to the children will propagate up, forcing
1823                  * us to become modified and copy-on-write too.
1824                  *
1825                  * Clear SUBMODIFIED now, races during the flush will re-set
1826                  * it.
1827                  */
1828                 hammer2_chain_modify(hmp, chain);
1829                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_SUBMODIFIED);
1830
1831                 /*
1832                  * The blockref in the parent's array must be repointed at
1833                  * the new block allocated by the child after its flush.
1834                  *
1835                  * Calculate the base of the array.
1836                  */
1837                 switch(chain->bref.type) {
1838                 case HAMMER2_BREF_TYPE_INODE:
1839                         KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
1840                         base = &chain->data->ipdata.u.blockset.blockref[0];
1841                         count = HAMMER2_SET_COUNT;
1842                         break;
1843                 case HAMMER2_BREF_TYPE_INDIRECT:
1844                         base = &chain->data->npdata.blockref[0];
1845                         count = chain->bytes / sizeof(hammer2_blockref_t);
1846                         break;
1847                 case HAMMER2_BREF_TYPE_VOLUME:
1848                         KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
1849                         base = &hmp->voldata.sroot_blockset.blockref[0];
1850                         count = HAMMER2_SET_COUNT;
1851                         break;
1852                 default:
1853                         base = NULL;
1854                         panic("hammer2_chain_get: unrecognized blockref type: %d",
1855                               chain->bref.type);
1856                 }
1857
1858                 /*
1859                  * Flush the children and update the blockrefs in the parent.
1860                  * Be careful of ripouts during the loop.
1861                  */
1862                 next = SPLAY_MIN(hammer2_chain_splay, &chain->shead);
1863                 while ((scan = next) != NULL) {
1864                         next = SPLAY_NEXT(hammer2_chain_splay, &chain->shead,
1865                                           scan);
1866                         if (scan->flags & (HAMMER2_CHAIN_SUBMODIFIED |
1867                                            HAMMER2_CHAIN_MODIFIED1 |
1868                                            HAMMER2_CHAIN_MOVED)) {
1869                                 hammer2_chain_ref(hmp, scan);
1870                                 hammer2_chain_lock(hmp, scan);
1871                                 hammer2_chain_flush_pass1(hmp, scan);
1872                                 if (scan->flags & (HAMMER2_CHAIN_SUBMODIFIED |
1873                                                    HAMMER2_CHAIN_MODIFIED1)) {
1874                                         submodified = 1;
1875                                 } else {
1876                                         KKASSERT(scan->index < count);
1877                                         base[scan->index] = scan->bref;
1878                                         if (scan->flags & HAMMER2_CHAIN_MOVED) {
1879                                                 atomic_clear_int(&scan->flags,
1880                                                          HAMMER2_CHAIN_MOVED);
1881                                                 hammer2_chain_drop(hmp, scan);
1882                                         }
1883                                 }
1884                                 hammer2_chain_put(hmp, scan);
1885                         }
1886                 }
1887                 if (submodified) {
1888                         atomic_set_int(&chain->flags,
1889                                        HAMMER2_CHAIN_SUBMODIFIED);
1890                 }
1891         }
1892
1893         /*
1894          * Flush this chain entry only if it is marked modified.
1895          */
1896         if ((chain->flags & HAMMER2_CHAIN_MODIFIED1) == 0)
1897                 return;
1898
1899         /*
1900          * Clear MODIFIED1 and set HAMMER2_CHAIN_MOVED.  The MODIFIED{1,2}
1901          * bits own a single parent ref and the MOVED bit owns its own
1902          * parent ref.
1903          */
1904         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
1905         if (chain->flags & HAMMER2_CHAIN_MOVED) {
1906                 if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
1907                         hammer2_chain_drop(hmp, chain);
1908         } else {
1909                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MOVED);
1910                 if (chain->flags & HAMMER2_CHAIN_MODIFIED2)
1911                         hammer2_chain_ref(hmp, chain);
1912         }
1913
1914         /*
1915          * If this is part of a recursive flush we can go ahead and write
1916          * out the buffer cache buffer and pass a new bref back up the chain.
1917          *
1918          * This will never be a volume header.
1919          */
1920         if (chain != &hmp->vchain) {
1921                 hammer2_blockref_t *bref;
1922                 hammer2_off_t off_hi;
1923                 struct buf *bp;
1924                 size_t off_lo;
1925                 size_t bytes;
1926                 int error;
1927
1928                 KKASSERT(chain->data != NULL);
1929                 bref = &chain->bref;
1930
1931                 off_hi = bref->data_off & HAMMER2_OFF_MASK_HI;
1932                 off_lo = (size_t)bref->data_off & HAMMER2_OFF_MASK_LO;
1933                 bytes = 1 << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
1934                 KKASSERT(off_hi != 0);  /* not the root volume header */
1935
1936                 if (chain->bp == NULL) {
1937                         /*
1938                          * The data is embedded, we have to acquire the
1939                          * buffer cache buffer and copy the data into it.
1940                          */
1941                         bp = NULL;
1942                         error = bread(hmp->devvp, off_hi,
1943                                       HAMMER2_PBUFSIZE, &bp);
1944                         KKASSERT(error == 0); /* XXX */
1945
1946                         /*
1947                          * Copy the data to the buffer, mark the buffer
1948                          * dirty, and convert the chain to unmodified.
1949                          */
1950                         bcopy(chain->data, (char *)bp->b_data + off_lo, bytes);
1951                         bdwrite(bp);
1952                         bp = NULL;
1953
1954                         chain->bref.check.iscsi32.value =
1955                                         hammer2_icrc32(chain->data, bytes);
1956                 }
1957         }
1958         {
1959                 hammer2_blockref_t *bref;
1960
1961                 bref = &chain->bref;
1962
1963                 switch(bref->type) {
1964                 case HAMMER2_BREF_TYPE_VOLUME:
1965                         KKASSERT(chain->data != NULL);
1966                         KKASSERT(chain->bp == NULL);
1967
1968                         hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT1]=
1969                                 hammer2_icrc32(
1970                                         (char *)&hmp->voldata +
1971                                          HAMMER2_VOLUME_ICRC1_OFF,
1972                                         HAMMER2_VOLUME_ICRC1_SIZE);
1973                         hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT0]=
1974                                 hammer2_icrc32(
1975                                         (char *)&hmp->voldata +
1976                                          HAMMER2_VOLUME_ICRC0_OFF,
1977                                         HAMMER2_VOLUME_ICRC0_SIZE);
1978                         hmp->voldata.icrc_volheader =
1979                                 hammer2_icrc32(
1980                                         (char *)&hmp->voldata +
1981                                          HAMMER2_VOLUME_ICRCVH_OFF,
1982                                         HAMMER2_VOLUME_ICRCVH_SIZE);
1983                         break;
1984                 }
1985         }
1986 }
1987
1988 #if 0
1989 /*
1990  * PASS2 - not yet implemented (should be called only with the root chain?)
1991  */
1992 static void
1993 hammer2_chain_flush_pass2(hammer2_mount_t *hmp, hammer2_chain_t *chain)
1994 {
1995 }
1996 #endif
1997
1998 void
1999 hammer2_chain_flush(hammer2_mount_t *hmp, hammer2_chain_t *chain)
2000 {
2001         hammer2_chain_flush_pass1(hmp, chain);
2002 }