sys/vfs/hammer2/hammer2_chain.c

   1 /*
   2  * Copyright (c) 2011-2018 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  * and 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 implements most of the core support functions for
  37  * the hammer2_chain structure.
  38  *
  39  * Chains are the in-memory version on media objects (volume header, inodes,
  40  * indirect blocks, data blocks, etc).  Chains represent a portion of the
  41  * HAMMER2 topology.
  42  *
  43  * Chains are no-longer delete-duplicated.  Instead, the original in-memory
  44  * chain will be moved along with its block reference (e.g. for things like
  45  * renames, hardlink operations, modifications, etc), and will be indexed
  46  * on a secondary list for flush handling instead of propagating a flag
  47  * upward to the root.
  48  *
  49  * Concurrent front-end operations can still run against backend flushes
  50  * as long as they do not cross the current flush boundary.  An operation
  51  * running above the current flush (in areas not yet flushed) can become
  52  * part of the current flush while ano peration running below the current
  53  * flush can become part of the next flush.
  54  */
  55 #include <sys/cdefs.h>
  56 #include <sys/param.h>
  57 #include <sys/systm.h>
  58 #include <sys/types.h>
  59 #include <sys/lock.h>
  60 #include <sys/kern_syscall.h>
  61 #include <sys/uuid.h>
  62
  63 #include <crypto/sha2/sha2.h>
  64
  65 #include "hammer2.h"
  66
  67 static hammer2_chain_t *hammer2_chain_create_indirect(
  68                 hammer2_chain_t *parent,
  69                 hammer2_key_t key, int keybits,
  70                 hammer2_tid_t mtid, int for_type, int *errorp);
  71 static hammer2_io_t *hammer2_chain_drop_data(hammer2_chain_t *chain);
  72 static hammer2_chain_t *hammer2_combined_find(
  73                 hammer2_chain_t *parent,
  74                 hammer2_blockref_t *base, int count,
  75                 hammer2_key_t *key_nextp,
  76                 hammer2_key_t key_beg, hammer2_key_t key_end,
  77                 hammer2_blockref_t **bresp);
  78
  79 static struct krate krate_h2me = { .freq = 1 };
  80
  81 /*
  82  * Basic RBTree for chains (core->rbtree and core->dbtree).  Chains cannot
  83  * overlap in the RB trees.  Deleted chains are moved from rbtree to either
  84  * dbtree or to dbq.
  85  *
  86  * Chains in delete-duplicate sequences can always iterate through core_entry
  87  * to locate the live version of the chain.
  88  */
  89 RB_GENERATE(hammer2_chain_tree, hammer2_chain, rbnode, hammer2_chain_cmp);
  90
  91 int
  92 hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2)
  93 {
  94         hammer2_key_t c1_beg;
  95         hammer2_key_t c1_end;
  96         hammer2_key_t c2_beg;
  97         hammer2_key_t c2_end;
  98
  99         /*
 100          * Compare chains.  Overlaps are not supposed to happen and catch
 101          * any software issues early we count overlaps as a match.
 102          */
 103         c1_beg = chain1->bref.key;
 104         c1_end = c1_beg + ((hammer2_key_t)1 << chain1->bref.keybits) - 1;
 105         c2_beg = chain2->bref.key;
 106         c2_end = c2_beg + ((hammer2_key_t)1 << chain2->bref.keybits) - 1;
 107
 108         if (c1_end < c2_beg)    /* fully to the left */
 109                 return(-1);
 110         if (c1_beg > c2_end)    /* fully to the right */
 111                 return(1);
 112         return(0);              /* overlap (must not cross edge boundary) */
 113 }
 114
 115 /*
 116  * Assert that a chain has no media data associated with it.
 117  */
 118 static __inline void
 119 hammer2_chain_assert_no_data(hammer2_chain_t *chain)
 120 {
 121         KKASSERT(chain->dio == NULL);
 122         if (chain->bref.type != HAMMER2_BREF_TYPE_VOLUME &&
 123             chain->bref.type != HAMMER2_BREF_TYPE_FREEMAP &&
 124             chain->data) {
 125                 panic("hammer2_assert_no_data: chain %p still has data", chain);
 126         }
 127 }
 128
 129 /*
 130  * Make a chain visible to the flusher.  The flusher needs to be able to
 131  * do flushes of subdirectory chains or single files so it does a top-down
 132  * recursion using the ONFLUSH flag for the recursion.  It locates MODIFIED
 133  * or UPDATE chains and flushes back up the chain to the volume root.
 134  *
 135  * This routine sets ONFLUSH upward until it hits the volume root.  For
 136  * simplicity we ignore PFSROOT boundaries whos rules can be complex.
 137  * Extra ONFLUSH flagging doesn't hurt the filesystem.
 138  */
 139 void
 140 hammer2_chain_setflush(hammer2_chain_t *chain)
 141 {
 142         hammer2_chain_t *parent;
 143
 144         if ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
 145                 hammer2_spin_sh(&chain->core.spin);
 146                 while ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
 147                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONFLUSH);
 148                         if ((parent = chain->parent) == NULL)
 149                                 break;
 150                         hammer2_spin_sh(&parent->core.spin);
 151                         hammer2_spin_unsh(&chain->core.spin);
 152                         chain = parent;
 153                 }
 154                 hammer2_spin_unsh(&chain->core.spin);
 155         }
 156 }
 157
 158 /*
 159  * Allocate a new disconnected chain element representing the specified
 160  * bref.  chain->refs is set to 1 and the passed bref is copied to
 161  * chain->bref.  chain->bytes is derived from the bref.
 162  *
 163  * chain->pmp inherits pmp unless the chain is an inode (other than the
 164  * super-root inode).
 165  *
 166  * NOTE: Returns a referenced but unlocked (because there is no core) chain.
 167  */
 168 hammer2_chain_t *
 169 hammer2_chain_alloc(hammer2_dev_t *hmp, hammer2_pfs_t *pmp,
 170                     hammer2_blockref_t *bref)
 171 {
 172         hammer2_chain_t *chain;
 173         u_int bytes;
 174
 175         /*
 176          * Special case - radix of 0 indicates a chain that does not
 177          * need a data reference (context is completely embedded in the
 178          * bref).
 179          */
 180         if ((int)(bref->data_off & HAMMER2_OFF_MASK_RADIX))
 181                 bytes = 1U << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
 182         else
 183                 bytes = 0;
 184
 185         atomic_add_long(&hammer2_chain_allocs, 1);
 186
 187         /*
 188          * Construct the appropriate system structure.
 189          */
 190         switch(bref->type) {
 191         case HAMMER2_BREF_TYPE_DIRENT:
 192         case HAMMER2_BREF_TYPE_INODE:
 193         case HAMMER2_BREF_TYPE_INDIRECT:
 194         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 195         case HAMMER2_BREF_TYPE_DATA:
 196         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
 197                 /*
 198                  * Chain's are really only associated with the hmp but we
 199                  * maintain a pmp association for per-mount memory tracking
 200                  * purposes.  The pmp can be NULL.
 201                  */
 202                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
 203                 break;
 204         case HAMMER2_BREF_TYPE_VOLUME:
 205         case HAMMER2_BREF_TYPE_FREEMAP:
 206                 /*
 207                  * Only hammer2_chain_bulksnap() calls this function with these
 208                  * types.
 209                  */
 210                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
 211                 break;
 212         default:
 213                 chain = NULL;
 214                 panic("hammer2_chain_alloc: unrecognized blockref type: %d",
 215                       bref->type);
 216         }
 217
 218         /*
 219          * Initialize the new chain structure.  pmp must be set to NULL for
 220          * chains belonging to the super-root topology of a device mount.
 221          */
 222         if (pmp == hmp->spmp)
 223                 chain->pmp = NULL;
 224         else
 225                 chain->pmp = pmp;
 226         chain->hmp = hmp;
 227         chain->bref = *bref;
 228         chain->bytes = bytes;
 229         chain->refs = 1;
 230         chain->flags = HAMMER2_CHAIN_ALLOCATED;
 231
 232         /*
 233          * Set the PFS boundary flag if this chain represents a PFS root.
 234          */
 235         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
 236                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_PFSBOUNDARY);
 237         hammer2_chain_core_init(chain);
 238
 239         return (chain);
 240 }
 241
 242 /*
 243  * Initialize a chain's core structure.  This structure used to be allocated
 244  * but is now embedded.
 245  *
 246  * The core is not locked.  No additional refs on the chain are made.
 247  * (trans) must not be NULL if (core) is not NULL.
 248  */
 249 void
 250 hammer2_chain_core_init(hammer2_chain_t *chain)
 251 {
 252         /*
 253          * Fresh core under nchain (no multi-homing of ochain's
 254          * sub-tree).
 255          */
 256         RB_INIT(&chain->core.rbtree);   /* live chains */
 257         hammer2_mtx_init(&chain->lock, "h2chain");
 258 }
 259
 260 /*
 261  * Add a reference to a chain element, preventing its destruction.
 262  *
 263  * (can be called with spinlock held)
 264  */
 265 void
 266 hammer2_chain_ref(hammer2_chain_t *chain)
 267 {
 268         if (atomic_fetchadd_int(&chain->refs, 1) == 0) {
 269                 /*
 270                  * Just flag that the chain was used and should be recycled
 271                  * on the LRU if it encounters it later.
 272                  */
 273                 if (chain->flags & HAMMER2_CHAIN_ONLRU)
 274                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_LRUHINT);
 275
 276 #if 0
 277                 /*
 278                  * REMOVED - reduces contention, lru_list is more heuristical
 279                  * now.
 280                  *
 281                  * 0->non-zero transition must ensure that chain is removed
 282                  * from the LRU list.
 283                  *
 284                  * NOTE: Already holding lru_spin here so we cannot call
 285                  *       hammer2_chain_ref() to get it off lru_list, do
 286                  *       it manually.
 287                  */
 288                 if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 289                         hammer2_pfs_t *pmp = chain->pmp;
 290                         hammer2_spin_ex(&pmp->lru_spin);
 291                         if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 292                                 atomic_add_int(&pmp->lru_count, -1);
 293                                 atomic_clear_int(&chain->flags,
 294                                                  HAMMER2_CHAIN_ONLRU);
 295                                 TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 296                         }
 297                         hammer2_spin_unex(&pmp->lru_spin);
 298                 }
 299 #endif
 300         }
 301 }
 302
 303 /*
 304  * Ref a locked chain and force the data to be held across an unlock.
 305  * Chain must be currently locked.  The user of the chain who desires
 306  * to release the hold must call hammer2_chain_lock_unhold() to relock
 307  * and unhold the chain, then unlock normally, or may simply call
 308  * hammer2_chain_drop_unhold() (which is safer against deadlocks).
 309  */
 310 void
 311 hammer2_chain_ref_hold(hammer2_chain_t *chain)
 312 {
 313         atomic_add_int(&chain->lockcnt, 1);
 314         hammer2_chain_ref(chain);
 315 }
 316
 317 /*
 318  * Insert the chain in the core rbtree.
 319  *
 320  * Normal insertions are placed in the live rbtree.  Insertion of a deleted
 321  * chain is a special case used by the flush code that is placed on the
 322  * unstaged deleted list to avoid confusing the live view.
 323  */
 324 #define HAMMER2_CHAIN_INSERT_SPIN       0x0001
 325 #define HAMMER2_CHAIN_INSERT_LIVE       0x0002
 326 #define HAMMER2_CHAIN_INSERT_RACE       0x0004
 327
 328 static
 329 int
 330 hammer2_chain_insert(hammer2_chain_t *parent, hammer2_chain_t *chain,
 331                      int flags, int generation)
 332 {
 333         hammer2_chain_t *xchain;
 334         int error = 0;
 335
 336         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
 337                 hammer2_spin_ex(&parent->core.spin);
 338
 339         /*
 340          * Interlocked by spinlock, check for race
 341          */
 342         if ((flags & HAMMER2_CHAIN_INSERT_RACE) &&
 343             parent->core.generation != generation) {
 344                 error = HAMMER2_ERROR_EAGAIN;
 345                 goto failed;
 346         }
 347
 348         /*
 349          * Insert chain
 350          */
 351         xchain = RB_INSERT(hammer2_chain_tree, &parent->core.rbtree, chain);
 352         KASSERT(xchain == NULL,
 353                 ("hammer2_chain_insert: collision %p %p (key=%016jx)",
 354                 chain, xchain, chain->bref.key));
 355         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
 356         chain->parent = parent;
 357         ++parent->core.chain_count;
 358         ++parent->core.generation;      /* XXX incs for _get() too, XXX */
 359
 360         /*
 361          * We have to keep track of the effective live-view blockref count
 362          * so the create code knows when to push an indirect block.
 363          */
 364         if (flags & HAMMER2_CHAIN_INSERT_LIVE)
 365                 atomic_add_int(&parent->core.live_count, 1);
 366 failed:
 367         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
 368                 hammer2_spin_unex(&parent->core.spin);
 369         return error;
 370 }
 371
 372 /*
 373  * Drop the caller's reference to the chain.  When the ref count drops to
 374  * zero this function will try to disassociate the chain from its parent and
 375  * deallocate it, then recursely drop the parent using the implied ref
 376  * from the chain's chain->parent.
 377  *
 378  * Nobody should own chain's mutex on the 1->0 transition, unless this drop
 379  * races an acquisition by another cpu.  Therefore we can loop if we are
 380  * unable to acquire the mutex, and refs is unlikely to be 1 unless we again
 381  * race against another drop.
 382  */
 383 static hammer2_chain_t *hammer2_chain_lastdrop(hammer2_chain_t *chain,
 384                                 int depth);
 385 static void hammer2_chain_lru_flush(hammer2_pfs_t *pmp);
 386
 387 void
 388 hammer2_chain_drop(hammer2_chain_t *chain)
 389 {
 390         u_int refs;
 391
 392         if (hammer2_debug & 0x200000)
 393                 Debugger("drop");
 394
 395         KKASSERT(chain->refs > 0);
 396
 397         while (chain) {
 398                 refs = chain->refs;
 399                 cpu_ccfence();
 400                 KKASSERT(refs > 0);
 401
 402                 if (refs == 1) {
 403                         if (hammer2_mtx_ex_try(&chain->lock) == 0)
 404                                 chain = hammer2_chain_lastdrop(chain, 0);
 405                         /* retry the same chain, or chain from lastdrop */
 406                 } else {
 407                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
 408                                 break;
 409                         /* retry the same chain */
 410                 }
 411                 cpu_pause();
 412         }
 413 }
 414
 415 /*
 416  * Unhold a held and probably not-locked chain, ensure that the data is
 417  * dropped on the 1->0 transition of lockcnt by obtaining an exclusive
 418  * lock and then simply unlocking the chain.
 419  */
 420 void
 421 hammer2_chain_drop_unhold(hammer2_chain_t *chain)
 422 {
 423         u_int lockcnt;
 424         int iter = 0;
 425
 426         for (;;) {
 427                 lockcnt = chain->lockcnt;
 428                 cpu_ccfence();
 429                 if (lockcnt > 1) {
 430                         if (atomic_cmpset_int(&chain->lockcnt,
 431                                               lockcnt, lockcnt - 1)) {
 432                                 break;
 433                         }
 434                 } else if (hammer2_mtx_ex_try(&chain->lock) == 0) {
 435                         hammer2_chain_unlock(chain);
 436                         break;
 437                 } else {
 438                         /*
 439                          * This situation can easily occur on SMP due to
 440                          * the gap inbetween the 1->0 transition and the
 441                          * final unlock.  We cannot safely block on the
 442                          * mutex because lockcnt might go above 1.
 443                          *
 444                          * XXX Sleep for one tick if it takes too long.
 445                          */
 446                         if (++iter > 1000) {
 447                                 if (iter > 1000 + hz) {
 448                                         kprintf("hammer2: h2race1 %p\n", chain);
 449                                         iter = 1000;
 450                                 }
 451                                 tsleep(&iter, 0, "h2race1", 1);
 452                         }
 453                         cpu_pause();
 454                 }
 455         }
 456         hammer2_chain_drop(chain);
 457 }
 458
 459 /*
 460  * Handles the (potential) last drop of chain->refs from 1->0.  Called with
 461  * the mutex exclusively locked, refs == 1, and lockcnt 0.  SMP races are
 462  * possible against refs and lockcnt.  We must dispose of the mutex on chain.
 463  *
 464  * This function returns an unlocked chain for recursive drop or NULL.  It
 465  * can return the same chain if it determines it has raced another ref.
 466  *
 467  * --
 468  *
 469  * When two chains need to be recursively dropped we use the chain we
 470  * would otherwise free to placehold the additional chain.  It's a bit
 471  * convoluted but we can't just recurse without potentially blowing out
 472  * the kernel stack.
 473  *
 474  * The chain cannot be freed if it has any children.
 475  * The chain cannot be freed if flagged MODIFIED unless we can dispose of it.
 476  * The chain cannot be freed if flagged UPDATE unless we can dispose of it.
 477  * Any dedup registration can remain intact.
 478  *
 479  * The core spinlock is allowed to nest child-to-parent (not parent-to-child).
 480  */
 481 static
 482 hammer2_chain_t *
 483 hammer2_chain_lastdrop(hammer2_chain_t *chain, int depth)
 484 {
 485         hammer2_pfs_t *pmp;
 486         hammer2_dev_t *hmp;
 487         hammer2_chain_t *parent;
 488         hammer2_chain_t *rdrop;
 489 #if 0
 490         hammer2_io_t *dio;
 491 #endif
 492
 493 #if 0
 494         /*
 495          * On last drop if there is no parent and data_off is good (at
 496          * least does not represent the volume root), the modified chain
 497          * is probably going to be destroyed.  We have to make sure that
 498          * the data area is not registered for dedup.
 499          *
 500          * XXX removed. In fact, we do not have to make sure that the
 501          *     data area is not registered for dedup.  The data area
 502          *     can, in fact, still be used for dedup because it is
 503          *     still allocated in the freemap and the underlying I/O
 504          *     will still be flushed.
 505          */
 506         if (chain->parent == NULL &&
 507             (chain->flags & HAMMER2_CHAIN_MODIFIED) &&
 508             (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
 509                 hmp = chain->hmp;
 510                 hammer2_io_dedup_delete(hmp, chain->bref.type,
 511                                         chain->bref.data_off, chain->bytes);
 512         }
 513 #endif
 514         /*
 515          * We need chain's spinlock to interlock the sub-tree test.
 516          * We already have chain's mutex, protecting chain->parent.
 517          *
 518          * Remember that chain->refs can be in flux.
 519          */
 520         hammer2_spin_ex(&chain->core.spin);
 521
 522         if (chain->parent != NULL) {
 523                 /*
 524                  * If the chain has a parent the UPDATE bit prevents scrapping
 525                  * as the chain is needed to properly flush the parent.  Try
 526                  * to complete the 1->0 transition and return NULL.  Retry
 527                  * (return chain) if we are unable to complete the 1->0
 528                  * transition, else return NULL (nothing more to do).
 529                  *
 530                  * If the chain has a parent the MODIFIED bit prevents
 531                  * scrapping.
 532                  *
 533                  * Chains with UPDATE/MODIFIED are *not* put on the LRU list!
 534                  */
 535                 if (chain->flags & (HAMMER2_CHAIN_UPDATE |
 536                                     HAMMER2_CHAIN_MODIFIED)) {
 537                         if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 538                                 hammer2_spin_unex(&chain->core.spin);
 539 #if 0
 540                                 dio = hammer2_chain_drop_data(chain, 0);
 541                                 if (dio)
 542                                         hammer2_io_bqrelse(&dio);
 543 #endif
 544                                 hammer2_chain_assert_no_data(chain);
 545                                 hammer2_mtx_unlock(&chain->lock);
 546                                 chain = NULL;
 547                         } else {
 548                                 hammer2_spin_unex(&chain->core.spin);
 549                                 hammer2_mtx_unlock(&chain->lock);
 550                         }
 551                         return (chain);
 552                 }
 553                 /* spinlock still held */
 554         } else if (chain->bref.type == HAMMER2_BREF_TYPE_VOLUME ||
 555                    chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP) {
 556                 /*
 557                  * Retain the static vchain and fchain.  Clear bits that
 558                  * are not relevant.  Do not clear the MODIFIED bit,
 559                  * and certainly do not put it on the delayed-flush queue.
 560                  */
 561                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 562         } else {
 563                 /*
 564                  * The chain has no parent and can be flagged for destruction.
 565                  * Since it has no parent, UPDATE can also be cleared.
 566                  */
 567                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
 568                 if (chain->flags & HAMMER2_CHAIN_UPDATE)
 569                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 570
 571                 /*
 572                  * If the chain has children we must still flush the chain.
 573                  * Any dedup is already handled by the underlying DIO, so
 574                  * we do not have to specifically flush it here.
 575                  *
 576                  * In the case where it has children, the DESTROY flag test
 577                  * in the flush code will prevent unnecessary flushes of
 578                  * MODIFIED chains that are not flagged DEDUP so don't worry
 579                  * about that here.
 580                  */
 581                 if (chain->core.chain_count) {
 582                         /*
 583                          * Put on flushq (should ensure refs > 1), retry
 584                          * the drop.
 585                          */
 586                         hammer2_spin_unex(&chain->core.spin);
 587                         hammer2_delayed_flush(chain);
 588                         hammer2_mtx_unlock(&chain->lock);
 589
 590                         return(chain);  /* retry drop */
 591                 }
 592
 593                 /*
 594                  * Otherwise we can scrap the MODIFIED bit if it is set,
 595                  * and continue along the freeing path.
 596                  *
 597                  * Be sure to clean-out any dedup bits.  Without a parent
 598                  * this chain will no longer be visible to the flush code.
 599                  * Easy check data_off to avoid the volume root.
 600                  */
 601                 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
 602                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 603                         atomic_add_long(&hammer2_count_modified_chains, -1);
 604                         if (chain->pmp)
 605                                 hammer2_pfs_memory_wakeup(chain->pmp);
 606                 }
 607                 /* spinlock still held */
 608         }
 609
 610         /* spinlock still held */
 611 #if 0
 612         dio = NULL;
 613 #endif
 614
 615         /*
 616          * If any children exist we must leave the chain intact with refs == 0.
 617          * They exist because chains are retained below us which have refs or
 618          * may require flushing.
 619          *
 620          * Retry (return chain) if we fail to transition the refs to 0, else
 621          * return NULL indication nothing more to do.
 622          *
 623          * Chains with children are NOT put on the LRU list.
 624          */
 625         if (chain->core.chain_count) {
 626                 if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 627                         hammer2_spin_unex(&chain->core.spin);
 628                         hammer2_chain_assert_no_data(chain);
 629                         hammer2_mtx_unlock(&chain->lock);
 630                         chain = NULL;
 631                 } else {
 632                         hammer2_spin_unex(&chain->core.spin);
 633                         hammer2_mtx_unlock(&chain->lock);
 634                 }
 635                 return (chain);
 636         }
 637         /* spinlock still held */
 638         /* no chains left under us */
 639
 640         /*
 641          * chain->core has no children left so no accessors can get to our
 642          * chain from there.  Now we have to lock the parent core to interlock
 643          * remaining possible accessors that might bump chain's refs before
 644          * we can safely drop chain's refs with intent to free the chain.
 645          */
 646         hmp = chain->hmp;
 647         pmp = chain->pmp;       /* can be NULL */
 648         rdrop = NULL;
 649
 650         parent = chain->parent;
 651
 652         /*
 653          * WARNING! chain's spin lock is still held here, and other spinlocks
 654          *          will be acquired and released in the code below.  We
 655          *          cannot be making fancy procedure calls!
 656          */
 657
 658         /*
 659          * We can cache the chain if it is associated with a pmp
 660          * and not flagged as being destroyed or requesting a full
 661          * release.  In this situation the chain is not removed
 662          * from its parent, i.e. it can still be looked up.
 663          *
 664          * We intentionally do not cache DATA chains because these
 665          * were likely used to load data into the logical buffer cache
 666          * and will not be accessed again for some time.
 667          */
 668         if ((chain->flags &
 669              (HAMMER2_CHAIN_DESTROY | HAMMER2_CHAIN_RELEASE)) == 0 &&
 670             chain->pmp &&
 671             chain->bref.type != HAMMER2_BREF_TYPE_DATA) {
 672                 if (parent)
 673                         hammer2_spin_ex(&parent->core.spin);
 674                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 675                         /*
 676                          * 1->0 transition failed, retry.  Do not drop
 677                          * the chain's data yet!
 678                          */
 679                         if (parent)
 680                                 hammer2_spin_unex(&parent->core.spin);
 681                         hammer2_spin_unex(&chain->core.spin);
 682                         hammer2_mtx_unlock(&chain->lock);
 683
 684                         return(chain);
 685                 }
 686
 687                 /*
 688                  * Success
 689                  */
 690 #if 0
 691                 dio = hammer2_chain_drop_data(chain, 1);
 692 #endif
 693                 hammer2_chain_assert_no_data(chain);
 694
 695                 /*
 696                  * Make sure we are on the LRU list, clean up excessive
 697                  * LRU entries.  We can only really drop one but there might
 698                  * be other entries that we can remove from the lru_list
 699                  * without dropping.
 700                  *
 701                  * NOTE: HAMMER2_CHAIN_ONLRU may only be safely set when
 702                  *       chain->core.spin AND pmp->lru_spin are held, but
 703                  *       can be safely cleared only holding pmp->lru_spin.
 704                  */
 705                 if ((chain->flags & HAMMER2_CHAIN_ONLRU) == 0) {
 706                         hammer2_spin_ex(&pmp->lru_spin);
 707                         if ((chain->flags & HAMMER2_CHAIN_ONLRU) == 0) {
 708                                 atomic_set_int(&chain->flags,
 709                                                HAMMER2_CHAIN_ONLRU);
 710                                 TAILQ_INSERT_TAIL(&pmp->lru_list,
 711                                                   chain, lru_node);
 712                                 atomic_add_int(&pmp->lru_count, 1);
 713                         }
 714                         if (pmp->lru_count < HAMMER2_LRU_LIMIT)
 715                                 depth = 1;      /* disable lru_list flush */
 716                         hammer2_spin_unex(&pmp->lru_spin);
 717                 } else {
 718                         /* disable lru flush */
 719                         depth = 1;
 720                 }
 721
 722                 if (parent) {
 723                         hammer2_spin_unex(&parent->core.spin);
 724                         parent = NULL;  /* safety */
 725                 }
 726                 hammer2_spin_unex(&chain->core.spin);
 727                 hammer2_mtx_unlock(&chain->lock);
 728 #if 0
 729                 if (dio)
 730                         hammer2_io_bqrelse(&dio);
 731 #endif
 732
 733                 /*
 734                  * lru_list hysteresis (see above for depth overrides).
 735                  * Note that depth also prevents excessive lastdrop recursion.
 736                  */
 737                 if (depth == 0)
 738                         hammer2_chain_lru_flush(pmp);
 739
 740                 return NULL;
 741                 /* NOT REACHED */
 742         }
 743
 744         /*
 745          * Make sure we are not on the LRU list.
 746          */
 747         if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 748                 hammer2_spin_ex(&pmp->lru_spin);
 749                 if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 750                         atomic_add_int(&pmp->lru_count, -1);
 751                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 752                         TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 753                 }
 754                 hammer2_spin_unex(&pmp->lru_spin);
 755         }
 756
 757         /*
 758          * Spinlock the parent and try to drop the last ref on chain.
 759          * On success determine if we should dispose of the chain
 760          * (remove the chain from its parent, etc).
 761          *
 762          * (normal core locks are top-down recursive but we define
 763          * core spinlocks as bottom-up recursive, so this is safe).
 764          */
 765         if (parent) {
 766                 hammer2_spin_ex(&parent->core.spin);
 767                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 768 #if 0
 769                         /* XXX remove, don't try to drop data on fail */
 770                         hammer2_spin_unex(&parent->core.spin);
 771                         dio = hammer2_chain_drop_data(chain, 0);
 772                         hammer2_spin_unex(&chain->core.spin);
 773                         if (dio)
 774                                 hammer2_io_bqrelse(&dio);
 775 #endif
 776                         /*
 777                          * 1->0 transition failed, retry.
 778                          */
 779                         hammer2_spin_unex(&parent->core.spin);
 780                         hammer2_spin_unex(&chain->core.spin);
 781                         hammer2_mtx_unlock(&chain->lock);
 782
 783                         return(chain);
 784                 }
 785
 786                 /*
 787                  * 1->0 transition successful, parent spin held to prevent
 788                  * new lookups, chain spinlock held to protect parent field.
 789                  * Remove chain from the parent.
 790                  *
 791                  * If the chain is being removed from the parent's btree but
 792                  * is not bmapped, we have to adjust live_count downward.  If
 793                  * it is bmapped then the blockref is retained in the parent
 794                  * as is its associated live_count.  This case can occur when
 795                  * a chain added to the topology is unable to flush and is
 796                  * then later deleted.
 797                  */
 798                 if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
 799                         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) &&
 800                             (chain->flags & HAMMER2_CHAIN_BMAPPED) == 0) {
 801                                 atomic_add_int(&parent->core.live_count, -1);
 802                         }
 803                         RB_REMOVE(hammer2_chain_tree,
 804                                   &parent->core.rbtree, chain);
 805                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
 806                         --parent->core.chain_count;
 807                         chain->parent = NULL;
 808                 }
 809
 810                 /*
 811                  * If our chain was the last chain in the parent's core the
 812                  * core is now empty and its parent might have to be
 813                  * re-dropped if it has 0 refs.
 814                  */
 815                 if (parent->core.chain_count == 0) {
 816                         rdrop = parent;
 817                         atomic_add_int(&rdrop->refs, 1);
 818                         /*
 819                         if (atomic_cmpset_int(&rdrop->refs, 0, 1) == 0)
 820                                 rdrop = NULL;
 821                         */
 822                 }
 823                 hammer2_spin_unex(&parent->core.spin);
 824                 parent = NULL;  /* safety */
 825                 /* FALL THROUGH */
 826         } else {
 827                 /*
 828                  * No-parent case.
 829                  */
 830                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 831                         /*
 832                          * 1->0 transition failed, retry.
 833                          */
 834                         hammer2_spin_unex(&parent->core.spin);
 835                         hammer2_spin_unex(&chain->core.spin);
 836                         hammer2_mtx_unlock(&chain->lock);
 837
 838                         return(chain);
 839                 }
 840         }
 841
 842         /*
 843          * Successful 1->0 transition, no parent, no children... no way for
 844          * anyone to ref this chain any more.  We can clean-up and free it.
 845          *
 846          * We still have the core spinlock, and core's chain_count is 0.
 847          * Any parent spinlock is gone.
 848          */
 849         hammer2_spin_unex(&chain->core.spin);
 850         hammer2_chain_assert_no_data(chain);
 851         hammer2_mtx_unlock(&chain->lock);
 852         KKASSERT(RB_EMPTY(&chain->core.rbtree) &&
 853                  chain->core.chain_count == 0);
 854
 855         /*
 856          * All locks are gone, no pointers remain to the chain, finish
 857          * freeing it.
 858          */
 859         KKASSERT((chain->flags & (HAMMER2_CHAIN_UPDATE |
 860                                   HAMMER2_CHAIN_MODIFIED)) == 0);
 861 #if 0
 862         dio = hammer2_chain_drop_data(chain, 1);
 863         if (dio)
 864                 hammer2_io_bqrelse(&dio);
 865 #endif
 866
 867         /*
 868          * Once chain resources are gone we can use the now dead chain
 869          * structure to placehold what might otherwise require a recursive
 870          * drop, because we have potentially two things to drop and can only
 871          * return one directly.
 872          */
 873         if (chain->flags & HAMMER2_CHAIN_ALLOCATED) {
 874                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ALLOCATED);
 875                 chain->hmp = NULL;
 876                 kfree(chain, hmp->mchain);
 877         }
 878
 879         /*
 880          * Possible chaining loop when parent re-drop needed.
 881          */
 882         return(rdrop);
 883 }
 884
 885 /*
 886  * Heuristical flush of the LRU, try to reduce the number of entries
 887  * on the LRU to (HAMMER2_LRU_LIMIT * 2 / 3).  This procedure is called
 888  * only when lru_count exceeds HAMMER2_LRU_LIMIT.
 889  */
 890 static
 891 void
 892 hammer2_chain_lru_flush(hammer2_pfs_t *pmp)
 893 {
 894         hammer2_chain_t *chain;
 895
 896 again:
 897         chain = NULL;
 898         hammer2_spin_ex(&pmp->lru_spin);
 899         while (pmp->lru_count > HAMMER2_LRU_LIMIT * 2 / 3) {
 900                 /*
 901                  * Pick a chain off the lru_list, just recycle it quickly
 902                  * if LRUHINT is set (the chain was ref'd but left on
 903                  * the lru_list, so cycle to the end).
 904                  */
 905                 chain = TAILQ_FIRST(&pmp->lru_list);
 906                 TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 907
 908                 if (chain->flags & HAMMER2_CHAIN_LRUHINT) {
 909                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_LRUHINT);
 910                         TAILQ_INSERT_TAIL(&pmp->lru_list, chain, lru_node);
 911                         chain = NULL;
 912                         continue;
 913                 }
 914
 915                 /*
 916                  * Ok, we are off the LRU.  We must adjust refs before we
 917                  * can safely clear the ONLRU flag.
 918                  */
 919                 atomic_add_int(&pmp->lru_count, -1);
 920                 if (atomic_cmpset_int(&chain->refs, 0, 1)) {
 921                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 922                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
 923                         break;
 924                 }
 925                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 926                 chain = NULL;
 927         }
 928         hammer2_spin_unex(&pmp->lru_spin);
 929         if (chain == NULL)
 930                 return;
 931
 932         /*
 933          * If we picked a chain off the lru list we may be able to lastdrop
 934          * it.  Use a depth of 1 to prevent excessive lastdrop recursion.
 935          */
 936         while (chain) {
 937                 u_int refs;
 938
 939                 refs = chain->refs;
 940                 cpu_ccfence();
 941                 KKASSERT(refs > 0);
 942
 943                 if (refs == 1) {
 944                         if (hammer2_mtx_ex_try(&chain->lock) == 0)
 945                                 chain = hammer2_chain_lastdrop(chain, 1);
 946                         /* retry the same chain, or chain from lastdrop */
 947                 } else {
 948                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
 949                                 break;
 950                         /* retry the same chain */
 951                 }
 952                 cpu_pause();
 953         }
 954         goto again;
 955 }
 956
 957 /*
 958  * On last lock release.
 959  */
 960 static hammer2_io_t *
 961 hammer2_chain_drop_data(hammer2_chain_t *chain)
 962 {
 963         hammer2_io_t *dio;
 964
 965         if ((dio = chain->dio) != NULL) {
 966                 chain->dio = NULL;
 967                 chain->data = NULL;
 968         } else {
 969                 switch(chain->bref.type) {
 970                 case HAMMER2_BREF_TYPE_VOLUME:
 971                 case HAMMER2_BREF_TYPE_FREEMAP:
 972                         break;
 973                 default:
 974                         if (chain->data != NULL) {
 975                                 hammer2_spin_unex(&chain->core.spin);
 976                                 panic("chain data not null: "
 977                                       "chain %p bref %016jx.%02x "
 978                                       "refs %d parent %p dio %p data %p",
 979                                       chain, chain->bref.data_off,
 980                                       chain->bref.type, chain->refs,
 981                                       chain->parent,
 982                                       chain->dio, chain->data);
 983                         }
 984                         KKASSERT(chain->data == NULL);
 985                         break;
 986                 }
 987         }
 988         return dio;
 989 }
 990
 991 /*
 992  * Lock a referenced chain element, acquiring its data with I/O if necessary,
 993  * and specify how you would like the data to be resolved.
 994  *
 995  * If an I/O or other fatal error occurs, chain->error will be set to non-zero.
 996  *
 997  * The lock is allowed to recurse, multiple locking ops will aggregate
 998  * the requested resolve types.  Once data is assigned it will not be
 999  * removed until the last unlock.
1000  *
1001  * HAMMER2_RESOLVE_NEVER - Do not resolve the data element.
1002  *                         (typically used to avoid device/logical buffer
1003  *                          aliasing for data)
1004  *
1005  * HAMMER2_RESOLVE_MAYBE - Do not resolve data elements for chains in
1006  *                         the INITIAL-create state (indirect blocks only).
1007  *
1008  *                         Do not resolve data elements for DATA chains.
1009  *                         (typically used to avoid device/logical buffer
1010  *                          aliasing for data)
1011  *
1012  * HAMMER2_RESOLVE_ALWAYS- Always resolve the data element.
1013  *
1014  * HAMMER2_RESOLVE_SHARED- (flag) The chain is locked shared, otherwise
1015  *                         it will be locked exclusive.
1016  *
1017  * HAMMER2_RESOLVE_NONBLOCK- (flag) The chain is locked non-blocking.  If
1018  *                         the lock fails, EAGAIN is returned.
1019  *
1020  * NOTE: Embedded elements (volume header, inodes) are always resolved
1021  *       regardless.
1022  *
1023  * NOTE: Specifying HAMMER2_RESOLVE_ALWAYS on a newly-created non-embedded
1024  *       element will instantiate and zero its buffer, and flush it on
1025  *       release.
1026  *
1027  * NOTE: (data) elements are normally locked RESOLVE_NEVER or RESOLVE_MAYBE
1028  *       so as not to instantiate a device buffer, which could alias against
1029  *       a logical file buffer.  However, if ALWAYS is specified the
1030  *       device buffer will be instantiated anyway.
1031  *
1032  * NOTE: The return value is always 0 unless NONBLOCK is specified, in which
1033  *       case it can be either 0 or EAGAIN.
1034  *
1035  * WARNING! This function blocks on I/O if data needs to be fetched.  This
1036  *          blocking can run concurrent with other compatible lock holders
1037  *          who do not need data returning.  The lock is not upgraded to
1038  *          exclusive during a data fetch, a separate bit is used to
1039  *          interlock I/O.  However, an exclusive lock holder can still count
1040  *          on being interlocked against an I/O fetch managed by a shared
1041  *          lock holder.
1042  */
1043 int
1044 hammer2_chain_lock(hammer2_chain_t *chain, int how)
1045 {
1046         KKASSERT(chain->refs > 0);
1047
1048         if (how & HAMMER2_RESOLVE_NONBLOCK) {
1049                 /*
1050                  * For non-blocking operation attempt to get the lock
1051                  * before bumping lockcnt, just so we don't have to deal
1052                  * with dropping lockcnt (and dealing with the underlying
1053                  * data) if we fail.
1054                  *
1055                  * NOTE: LOCKAGAIN must always succeed without blocking.
1056                  */
1057                 if (how & HAMMER2_RESOLVE_SHARED) {
1058                         if (how & HAMMER2_RESOLVE_LOCKAGAIN) {
1059                                 hammer2_mtx_sh_again(&chain->lock);
1060                         } else {
1061                                 if (hammer2_mtx_sh_try(&chain->lock) != 0)
1062                                         return EAGAIN;
1063                         }
1064                 } else {
1065                         if (hammer2_mtx_ex_try(&chain->lock) != 0)
1066                                 return EAGAIN;
1067                 }
1068                 atomic_add_int(&chain->lockcnt, 1);
1069                 ++curthread->td_tracker;
1070         } else {
1071                 /*
1072                  * Lock the element.  Recursive locks are allowed.  lockcnt
1073                  * ensures that data is left intact.
1074                  */
1075                 atomic_add_int(&chain->lockcnt, 1);
1076
1077                 /*
1078                  * Get the appropriate lock.  If LOCKAGAIN is flagged with
1079                  * SHARED the caller expects a shared lock to already be
1080                  * present and we are giving it another ref.  This case must
1081                  * importantly not block if there is a pending exclusive lock
1082                  * request.
1083                  */
1084                 if (how & HAMMER2_RESOLVE_SHARED) {
1085                         if (how & HAMMER2_RESOLVE_LOCKAGAIN) {
1086                                 hammer2_mtx_sh_again(&chain->lock);
1087                         } else {
1088                                 hammer2_mtx_sh(&chain->lock);
1089                         }
1090                 } else {
1091                         hammer2_mtx_ex(&chain->lock);
1092                 }
1093                 ++curthread->td_tracker;
1094         }
1095
1096         /*
1097          * If we already have a valid data pointer make sure the data is
1098          * synchronized to the current cpu, and then no further action is
1099          * necessary.
1100          */
1101         if (chain->data) {
1102                 if (chain->dio)
1103                         hammer2_io_bkvasync(chain->dio);
1104                 return 0;
1105         }
1106
1107         /*
1108          * Do we have to resolve the data?  This is generally only
1109          * applicable to HAMMER2_BREF_TYPE_DATA which is special-cased.
1110          * Other BREF types expects the data to be there.
1111          */
1112         switch(how & HAMMER2_RESOLVE_MASK) {
1113         case HAMMER2_RESOLVE_NEVER:
1114                 return 0;
1115         case HAMMER2_RESOLVE_MAYBE:
1116                 if (chain->flags & HAMMER2_CHAIN_INITIAL)
1117                         return 0;
1118                 if (chain->bref.type == HAMMER2_BREF_TYPE_DATA)
1119                         return 0;
1120 #if 0
1121                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE)
1122                         return 0;
1123                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF)
1124                         return 0;
1125 #endif
1126                 /* fall through */
1127         case HAMMER2_RESOLVE_ALWAYS:
1128         default:
1129                 break;
1130         }
1131
1132         /*
1133          * Caller requires data
1134          */
1135         hammer2_chain_load_data(chain);
1136
1137         return 0;
1138 }
1139
1140 /*
1141  * Lock the chain, retain the hold, and drop the data persistence count.
1142  * The data should remain valid because we never transitioned lockcnt
1143  * through 0.
1144  */
1145 void
1146 hammer2_chain_lock_unhold(hammer2_chain_t *chain, int how)
1147 {
1148         hammer2_chain_lock(chain, how);
1149         atomic_add_int(&chain->lockcnt, -1);
1150 }
1151
1152 #if 0
1153 /*
1154  * Downgrade an exclusive chain lock to a shared chain lock.
1155  *
1156  * NOTE: There is no upgrade equivalent due to the ease of
1157  *       deadlocks in that direction.
1158  */
1159 void
1160 hammer2_chain_lock_downgrade(hammer2_chain_t *chain)
1161 {
1162         hammer2_mtx_downgrade(&chain->lock);
1163 }
1164 #endif
1165
1166 /*
1167  * Issue I/O and install chain->data.  Caller must hold a chain lock, lock
1168  * may be of any type.
1169  *
1170  * Once chain->data is set it cannot be disposed of until all locks are
1171  * released.
1172  *
1173  * Make sure the data is synchronized to the current cpu.
1174  */
1175 void
1176 hammer2_chain_load_data(hammer2_chain_t *chain)
1177 {
1178         hammer2_blockref_t *bref;
1179         hammer2_dev_t *hmp;
1180         hammer2_io_t *dio;
1181         char *bdata;
1182         int error;
1183
1184         /*
1185          * Degenerate case, data already present, or chain has no media
1186          * reference to load.
1187          */
1188         if (chain->data) {
1189                 if (chain->dio)
1190                         hammer2_io_bkvasync(chain->dio);
1191                 return;
1192         }
1193         if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0)
1194                 return;
1195
1196         hmp = chain->hmp;
1197         KKASSERT(hmp != NULL);
1198
1199         /*
1200          * Gain the IOINPROG bit, interlocked block.
1201          */
1202         for (;;) {
1203                 u_int oflags;
1204                 u_int nflags;
1205
1206                 oflags = chain->flags;
1207                 cpu_ccfence();
1208                 if (oflags & HAMMER2_CHAIN_IOINPROG) {
1209                         nflags = oflags | HAMMER2_CHAIN_IOSIGNAL;
1210                         tsleep_interlock(&chain->flags, 0);
1211                         if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1212                                 tsleep(&chain->flags, PINTERLOCKED,
1213                                         "h2iocw", 0);
1214                         }
1215                         /* retry */
1216                 } else {
1217                         nflags = oflags | HAMMER2_CHAIN_IOINPROG;
1218                         if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1219                                 break;
1220                         }
1221                         /* retry */
1222                 }
1223         }
1224
1225         /*
1226          * We own CHAIN_IOINPROG
1227          *
1228          * Degenerate case if we raced another load.
1229          */
1230         if (chain->data) {
1231                 if (chain->dio)
1232                         hammer2_io_bkvasync(chain->dio);
1233                 goto done;
1234         }
1235
1236         /*
1237          * We must resolve to a device buffer, either by issuing I/O or
1238          * by creating a zero-fill element.  We do not mark the buffer
1239          * dirty when creating a zero-fill element (the hammer2_chain_modify()
1240          * API must still be used to do that).
1241          *
1242          * The device buffer is variable-sized in powers of 2 down
1243          * to HAMMER2_MIN_ALLOC (typically 1K).  A 64K physical storage
1244          * chunk always contains buffers of the same size. (XXX)
1245          *
1246          * The minimum physical IO size may be larger than the variable
1247          * block size.
1248          */
1249         bref = &chain->bref;
1250
1251         /*
1252          * The getblk() optimization can only be used on newly created
1253          * elements if the physical block size matches the request.
1254          */
1255         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1256                 error = hammer2_io_new(hmp, bref->type,
1257                                        bref->data_off, chain->bytes,
1258                                        &chain->dio);
1259         } else {
1260                 error = hammer2_io_bread(hmp, bref->type,
1261                                          bref->data_off, chain->bytes,
1262                                          &chain->dio);
1263                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1264         }
1265         if (error) {
1266                 chain->error = HAMMER2_ERROR_EIO;
1267                 kprintf("hammer2_chain_lock: I/O error %016jx: %d\n",
1268                         (intmax_t)bref->data_off, error);
1269                 hammer2_io_bqrelse(&chain->dio);
1270                 goto done;
1271         }
1272         chain->error = 0;
1273
1274         /*
1275          * This isn't perfect and can be ignored on OSs which do not have
1276          * an indication as to whether a buffer is coming from cache or
1277          * if I/O was actually issued for the read.  TESTEDGOOD will work
1278          * pretty well without the B_IOISSUED logic because chains are
1279          * cached, but in that situation (without B_IOISSUED) it will not
1280          * detect whether a re-read via I/O is corrupted verses the original
1281          * read.
1282          *
1283          * We can't re-run the CRC on every fresh lock.  That would be
1284          * insanely expensive.
1285          *
1286          * If the underlying kernel buffer covers the entire chain we can
1287          * use the B_IOISSUED indication to determine if we have to re-run
1288          * the CRC on chain data for chains that managed to stay cached
1289          * across the kernel disposal of the original buffer.
1290          */
1291         if ((dio = chain->dio) != NULL && dio->bp) {
1292                 struct buf *bp = dio->bp;
1293
1294                 if (dio->psize == chain->bytes &&
1295                     (bp->b_flags & B_IOISSUED)) {
1296                         atomic_clear_int(&chain->flags,
1297                                          HAMMER2_CHAIN_TESTEDGOOD);
1298                         bp->b_flags &= ~B_IOISSUED;
1299                 }
1300         }
1301
1302         /*
1303          * NOTE: A locked chain's data cannot be modified without first
1304          *       calling hammer2_chain_modify().
1305          */
1306
1307         /*
1308          * Clear INITIAL.  In this case we used io_new() and the buffer has
1309          * been zero'd and marked dirty.
1310          *
1311          * NOTE: hammer2_io_data() call issues bkvasync()
1312          */
1313         bdata = hammer2_io_data(chain->dio, chain->bref.data_off);
1314
1315         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1316                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1317                 chain->bref.flags |= HAMMER2_BREF_FLAG_ZERO;
1318         } else if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
1319                 /*
1320                  * check data not currently synchronized due to
1321                  * modification.  XXX assumes data stays in the buffer
1322                  * cache, which might not be true (need biodep on flush
1323                  * to calculate crc?  or simple crc?).
1324                  */
1325         } else if ((chain->flags & HAMMER2_CHAIN_TESTEDGOOD) == 0) {
1326                 if (hammer2_chain_testcheck(chain, bdata) == 0) {
1327                         chain->error = HAMMER2_ERROR_CHECK;
1328                 } else {
1329                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_TESTEDGOOD);
1330                 }
1331         }
1332
1333         /*
1334          * Setup the data pointer, either pointing it to an embedded data
1335          * structure and copying the data from the buffer, or pointing it
1336          * into the buffer.
1337          *
1338          * The buffer is not retained when copying to an embedded data
1339          * structure in order to avoid potential deadlocks or recursions
1340          * on the same physical buffer.
1341          *
1342          * WARNING! Other threads can start using the data the instant we
1343          *          set chain->data non-NULL.
1344          */
1345         switch (bref->type) {
1346         case HAMMER2_BREF_TYPE_VOLUME:
1347         case HAMMER2_BREF_TYPE_FREEMAP:
1348                 /*
1349                  * Copy data from bp to embedded buffer
1350                  */
1351                 panic("hammer2_chain_load_data: unresolved volume header");
1352                 break;
1353         case HAMMER2_BREF_TYPE_DIRENT:
1354                 KKASSERT(chain->bytes != 0);
1355                 /* fall through */
1356         case HAMMER2_BREF_TYPE_INODE:
1357         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1358         case HAMMER2_BREF_TYPE_INDIRECT:
1359         case HAMMER2_BREF_TYPE_DATA:
1360         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1361         default:
1362                 /*
1363                  * Point data at the device buffer and leave dio intact.
1364                  */
1365                 chain->data = (void *)bdata;
1366                 break;
1367         }
1368
1369         /*
1370          * Release HAMMER2_CHAIN_IOINPROG and signal waiters if requested.
1371          */
1372 done:
1373         for (;;) {
1374                 u_int oflags;
1375                 u_int nflags;
1376
1377                 oflags = chain->flags;
1378                 nflags = oflags & ~(HAMMER2_CHAIN_IOINPROG |
1379                                     HAMMER2_CHAIN_IOSIGNAL);
1380                 KKASSERT(oflags & HAMMER2_CHAIN_IOINPROG);
1381                 if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1382                         if (oflags & HAMMER2_CHAIN_IOSIGNAL)
1383                                 wakeup(&chain->flags);
1384                         break;
1385                 }
1386         }
1387 }
1388
1389 /*
1390  * Unlock and deref a chain element.
1391  *
1392  * Remember that the presence of children under chain prevent the chain's
1393  * destruction but do not add additional references, so the dio will still
1394  * be dropped.
1395  */
1396 void
1397 hammer2_chain_unlock(hammer2_chain_t *chain)
1398 {
1399         hammer2_io_t *dio;
1400         u_int lockcnt;
1401         int iter = 0;
1402
1403         --curthread->td_tracker;
1404
1405         /*
1406          * If multiple locks are present (or being attempted) on this
1407          * particular chain we can just unlock, drop refs, and return.
1408          *
1409          * Otherwise fall-through on the 1->0 transition.
1410          */
1411         for (;;) {
1412                 lockcnt = chain->lockcnt;
1413                 KKASSERT(lockcnt > 0);
1414                 cpu_ccfence();
1415                 if (lockcnt > 1) {
1416                         if (atomic_cmpset_int(&chain->lockcnt,
1417                                               lockcnt, lockcnt - 1)) {
1418                                 hammer2_mtx_unlock(&chain->lock);
1419                                 return;
1420                         }
1421                 } else if (hammer2_mtx_upgrade_try(&chain->lock) == 0) {
1422                         /* while holding the mutex exclusively */
1423                         if (atomic_cmpset_int(&chain->lockcnt, 1, 0))
1424                                 break;
1425                 } else {
1426                         /*
1427                          * This situation can easily occur on SMP due to
1428                          * the gap inbetween the 1->0 transition and the
1429                          * final unlock.  We cannot safely block on the
1430                          * mutex because lockcnt might go above 1.
1431                          *
1432                          * XXX Sleep for one tick if it takes too long.
1433                          */
1434                         if (++iter > 1000) {
1435                                 if (iter > 1000 + hz) {
1436                                         kprintf("hammer2: h2race2 %p\n", chain);
1437                                         iter = 1000;
1438                                 }
1439                                 tsleep(&iter, 0, "h2race2", 1);
1440                         }
1441                         cpu_pause();
1442                 }
1443                 /* retry */
1444         }
1445
1446         /*
1447          * Last unlock / mutex upgraded to exclusive.  Drop the data
1448          * reference.
1449          */
1450         dio = hammer2_chain_drop_data(chain);
1451         if (dio)
1452                 hammer2_io_bqrelse(&dio);
1453         hammer2_mtx_unlock(&chain->lock);
1454 }
1455
1456 /*
1457  * Unlock and hold chain data intact
1458  */
1459 void
1460 hammer2_chain_unlock_hold(hammer2_chain_t *chain)
1461 {
1462         atomic_add_int(&chain->lockcnt, 1);
1463         hammer2_chain_unlock(chain);
1464 }
1465
1466 /*
1467  * Helper to obtain the blockref[] array base and count for a chain.
1468  *
1469  * XXX Not widely used yet, various use cases need to be validated and
1470  *     converted to use this function.
1471  */
1472 static
1473 hammer2_blockref_t *
1474 hammer2_chain_base_and_count(hammer2_chain_t *parent, int *countp)
1475 {
1476         hammer2_blockref_t *base;
1477         int count;
1478
1479         if (parent->flags & HAMMER2_CHAIN_INITIAL) {
1480                 base = NULL;
1481
1482                 switch(parent->bref.type) {
1483                 case HAMMER2_BREF_TYPE_INODE:
1484                         count = HAMMER2_SET_COUNT;
1485                         break;
1486                 case HAMMER2_BREF_TYPE_INDIRECT:
1487                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1488                         count = parent->bytes / sizeof(hammer2_blockref_t);
1489                         break;
1490                 case HAMMER2_BREF_TYPE_VOLUME:
1491                         count = HAMMER2_SET_COUNT;
1492                         break;
1493                 case HAMMER2_BREF_TYPE_FREEMAP:
1494                         count = HAMMER2_SET_COUNT;
1495                         break;
1496                 default:
1497                         panic("hammer2_chain_create_indirect: "
1498                               "unrecognized blockref type: %d",
1499                               parent->bref.type);
1500                         count = 0;
1501                         break;
1502                 }
1503         } else {
1504                 switch(parent->bref.type) {
1505                 case HAMMER2_BREF_TYPE_INODE:
1506                         base = &parent->data->ipdata.u.blockset.blockref[0];
1507                         count = HAMMER2_SET_COUNT;
1508                         break;
1509                 case HAMMER2_BREF_TYPE_INDIRECT:
1510                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1511                         base = &parent->data->npdata[0];
1512                         count = parent->bytes / sizeof(hammer2_blockref_t);
1513                         break;
1514                 case HAMMER2_BREF_TYPE_VOLUME:
1515                         base = &parent->data->voldata.
1516                                         sroot_blockset.blockref[0];
1517                         count = HAMMER2_SET_COUNT;
1518                         break;
1519                 case HAMMER2_BREF_TYPE_FREEMAP:
1520                         base = &parent->data->blkset.blockref[0];
1521                         count = HAMMER2_SET_COUNT;
1522                         break;
1523                 default:
1524                         panic("hammer2_chain_create_indirect: "
1525                               "unrecognized blockref type: %d",
1526                               parent->bref.type);
1527                         count = 0;
1528                         break;
1529                 }
1530         }
1531         *countp = count;
1532
1533         return base;
1534 }
1535
1536 /*
1537  * This counts the number of live blockrefs in a block array and
1538  * also calculates the point at which all remaining blockrefs are empty.
1539  * This routine can only be called on a live chain.
1540  *
1541  * Caller holds the chain locked, but possibly with a shared lock.  We
1542  * must use an exclusive spinlock to prevent corruption.
1543  *
1544  * NOTE: Flag is not set until after the count is complete, allowing
1545  *       callers to test the flag without holding the spinlock.
1546  *
1547  * NOTE: If base is NULL the related chain is still in the INITIAL
1548  *       state and there are no blockrefs to count.
1549  *
1550  * NOTE: live_count may already have some counts accumulated due to
1551  *       creation and deletion and could even be initially negative.
1552  */
1553 void
1554 hammer2_chain_countbrefs(hammer2_chain_t *chain,
1555                          hammer2_blockref_t *base, int count)
1556 {
1557         hammer2_spin_ex(&chain->core.spin);
1558         if ((chain->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0) {
1559                 if (base) {
1560                         while (--count >= 0) {
1561                                 if (base[count].type)
1562                                         break;
1563                         }
1564                         chain->core.live_zero = count + 1;
1565                         while (count >= 0) {
1566                                 if (base[count].type)
1567                                         atomic_add_int(&chain->core.live_count,
1568                                                        1);
1569                                 --count;
1570                         }
1571                 } else {
1572                         chain->core.live_zero = 0;
1573                 }
1574                 /* else do not modify live_count */
1575                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_COUNTEDBREFS);
1576         }
1577         hammer2_spin_unex(&chain->core.spin);
1578 }
1579
1580 /*
1581  * Resize the chain's physical storage allocation in-place.  This function does
1582  * not usually adjust the data pointer and must be followed by (typically) a
1583  * hammer2_chain_modify() call to copy any old data over and adjust the
1584  * data pointer.
1585  *
1586  * Chains can be resized smaller without reallocating the storage.  Resizing
1587  * larger will reallocate the storage.  Excess or prior storage is reclaimed
1588  * asynchronously at a later time.
1589  *
1590  * An nradix value of 0 is special-cased to mean that the storage should
1591  * be disassociated, that is the chain is being resized to 0 bytes (not 1
1592  * byte).
1593  *
1594  * Must be passed an exclusively locked parent and chain.
1595  *
1596  * This function is mostly used with DATA blocks locked RESOLVE_NEVER in order
1597  * to avoid instantiating a device buffer that conflicts with the vnode data
1598  * buffer.  However, because H2 can compress or encrypt data, the chain may
1599  * have a dio assigned to it in those situations, and they do not conflict.
1600  *
1601  * XXX return error if cannot resize.
1602  */
1603 int
1604 hammer2_chain_resize(hammer2_chain_t *chain,
1605                      hammer2_tid_t mtid, hammer2_off_t dedup_off,
1606                      int nradix, int flags)
1607 {
1608         hammer2_dev_t *hmp;
1609         size_t obytes;
1610         size_t nbytes;
1611         int error;
1612
1613         hmp = chain->hmp;
1614
1615         /*
1616          * Only data and indirect blocks can be resized for now.
1617          * (The volu root, inodes, and freemap elements use a fixed size).
1618          */
1619         KKASSERT(chain != &hmp->vchain);
1620         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1621                  chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
1622                  chain->bref.type == HAMMER2_BREF_TYPE_DIRENT);
1623
1624         /*
1625          * Nothing to do if the element is already the proper size
1626          */
1627         obytes = chain->bytes;
1628         nbytes = (nradix) ? (1U << nradix) : 0;
1629         if (obytes == nbytes)
1630                 return (chain->error);
1631
1632         /*
1633          * Make sure the old data is instantiated so we can copy it.  If this
1634          * is a data block, the device data may be superfluous since the data
1635          * might be in a logical block, but compressed or encrypted data is
1636          * another matter.
1637          *
1638          * NOTE: The modify will set BMAPUPD for us if BMAPPED is set.
1639          */
1640         error = hammer2_chain_modify(chain, mtid, dedup_off, 0);
1641         if (error)
1642                 return error;
1643
1644         /*
1645          * Relocate the block, even if making it smaller (because different
1646          * block sizes may be in different regions).
1647          *
1648          * NOTE: Operation does not copy the data and may only be used
1649          *        to resize data blocks in-place, or directory entry blocks
1650          *        which are about to be modified in some manner.
1651          */
1652         error = hammer2_freemap_alloc(chain, nbytes);
1653         if (error)
1654                 return error;
1655
1656         chain->bytes = nbytes;
1657
1658         /*
1659          * We don't want the followup chain_modify() to try to copy data
1660          * from the old (wrong-sized) buffer.  It won't know how much to
1661          * copy.  This case should only occur during writes when the
1662          * originator already has the data to write in-hand.
1663          */
1664         if (chain->dio) {
1665                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1666                          chain->bref.type == HAMMER2_BREF_TYPE_DIRENT);
1667                 hammer2_io_brelse(&chain->dio);
1668                 chain->data = NULL;
1669         }
1670         return (chain->error);
1671 }
1672
1673 /*
1674  * Set the chain modified so its data can be changed by the caller, or
1675  * install deduplicated data.  The caller must call this routine for each
1676  * set of modifications it makes, even if the chain is already flagged
1677  * MODIFIED.
1678  *
1679  * Sets bref.modify_tid to mtid only if mtid != 0.  Note that bref.modify_tid
1680  * is a CLC (cluster level change) field and is not updated by parent
1681  * propagation during a flush.
1682  *
1683  * Returns an appropriate HAMMER2_ERROR_* code, which will generally reflect
1684  * chain->error except for HAMMER2_ERROR_ENOSPC.  If the allocation fails
1685  * due to no space available, HAMMER2_ERROR_ENOSPC is returned and the chain
1686  * remains unmodified with its old data ref intact and chain->error
1687  * unchanged.
1688  *
1689  *                               Dedup Handling
1690  *
1691  * If the DEDUPABLE flag is set in the chain the storage must be reallocated
1692  * even if the chain is still flagged MODIFIED.  In this case the chain's
1693  * DEDUPABLE flag will be cleared once the new storage has been assigned.
1694  *
1695  * If the caller passes a non-zero dedup_off we will use it to assign the
1696  * new storage.  The MODIFIED flag will be *CLEARED* in this case, and
1697  * DEDUPABLE will be set (NOTE: the UPDATE flag is always set).  The caller
1698  * must not modify the data content upon return.
1699  */
1700 int
1701 hammer2_chain_modify(hammer2_chain_t *chain, hammer2_tid_t mtid,
1702                      hammer2_off_t dedup_off, int flags)
1703 {
1704         hammer2_blockref_t obref;
1705         hammer2_dev_t *hmp;
1706         hammer2_io_t *dio;
1707         int error;
1708         int wasinitial;
1709         int setmodified;
1710         int setupdate;
1711         int newmod;
1712         char *bdata;
1713
1714         hmp = chain->hmp;
1715         obref = chain->bref;
1716         KKASSERT((chain->flags & HAMMER2_CHAIN_FICTITIOUS) == 0);
1717
1718         /*
1719          * Data is not optional for freemap chains (we must always be sure
1720          * to copy the data on COW storage allocations).
1721          */
1722         if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
1723             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
1724                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) ||
1725                          (flags & HAMMER2_MODIFY_OPTDATA) == 0);
1726         }
1727
1728         /*
1729          * Data must be resolved if already assigned, unless explicitly
1730          * flagged otherwise.  If we cannot safety load the data the
1731          * modification fails and we return early.
1732          */
1733         if (chain->data == NULL && chain->bytes != 0 &&
1734             (flags & HAMMER2_MODIFY_OPTDATA) == 0 &&
1735             (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
1736                 hammer2_chain_load_data(chain);
1737                 if (chain->error)
1738                         return (chain->error);
1739         }
1740         error = 0;
1741
1742         /*
1743          * Set MODIFIED to indicate that the chain has been modified.  A new
1744          * allocation is required when modifying a chain.
1745          *
1746          * Set UPDATE to ensure that the blockref is updated in the parent.
1747          *
1748          * If MODIFIED is already set determine if we can reuse the assigned
1749          * data block or if we need a new data block.
1750          */
1751         if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0) {
1752                 /*
1753                  * Must set modified bit.
1754                  */
1755                 atomic_add_long(&hammer2_count_modified_chains, 1);
1756                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1757                 hammer2_pfs_memory_inc(chain->pmp);  /* can be NULL */
1758                 setmodified = 1;
1759
1760                 /*
1761                  * We may be able to avoid a copy-on-write if the chain's
1762                  * check mode is set to NONE and the chain's current
1763                  * modify_tid is beyond the last explicit snapshot tid.
1764                  *
1765                  * This implements HAMMER2's overwrite-in-place feature.
1766                  *
1767                  * NOTE! This data-block cannot be used as a de-duplication
1768                  *       source when the check mode is set to NONE.
1769                  */
1770                 if ((chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1771                      chain->bref.type == HAMMER2_BREF_TYPE_DIRENT) &&
1772                     (chain->flags & HAMMER2_CHAIN_INITIAL) == 0 &&
1773                     (chain->flags & HAMMER2_CHAIN_DEDUPABLE) == 0 &&
1774                     HAMMER2_DEC_CHECK(chain->bref.methods) ==
1775                      HAMMER2_CHECK_NONE &&
1776                     chain->pmp &&
1777                     chain->bref.modify_tid >
1778                      chain->pmp->iroot->meta.pfs_lsnap_tid) {
1779                         /*
1780                          * Sector overwrite allowed.
1781                          */
1782                         newmod = 0;
1783                 } else {
1784                         /*
1785                          * Sector overwrite not allowed, must copy-on-write.
1786                          */
1787                         newmod = 1;
1788                 }
1789         } else if (chain->flags & HAMMER2_CHAIN_DEDUPABLE) {
1790                 /*
1791                  * If the modified chain was registered for dedup we need
1792                  * a new allocation.  This only happens for delayed-flush
1793                  * chains (i.e. which run through the front-end buffer
1794                  * cache).
1795                  */
1796                 newmod = 1;
1797                 setmodified = 0;
1798         } else {
1799                 /*
1800                  * Already flagged modified, no new allocation is needed.
1801                  */
1802                 newmod = 0;
1803                 setmodified = 0;
1804         }
1805
1806         /*
1807          * Flag parent update required.
1808          */
1809         if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0) {
1810                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1811                 setupdate = 1;
1812         } else {
1813                 setupdate = 0;
1814         }
1815
1816         /*
1817          * The modification or re-modification requires an allocation and
1818          * possible COW.  If an error occurs, the previous content and data
1819          * reference is retained and the modification fails.
1820          *
1821          * If dedup_off is non-zero, the caller is requesting a deduplication
1822          * rather than a modification.  The MODIFIED bit is not set and the
1823          * data offset is set to the deduplication offset.  The data cannot
1824          * be modified.
1825          *
1826          * NOTE: The dedup offset is allowed to be in a partially free state
1827          *       and we must be sure to reset it to a fully allocated state
1828          *       to force two bulkfree passes to free it again.
1829          *
1830          * NOTE: Only applicable when chain->bytes != 0.
1831          *
1832          * XXX can a chain already be marked MODIFIED without a data
1833          * assignment?  If not, assert here instead of testing the case.
1834          */
1835         if (chain != &hmp->vchain && chain != &hmp->fchain &&
1836             chain->bytes) {
1837                 if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0 ||
1838                      newmod
1839                 ) {
1840                         /*
1841                          * NOTE: We do not have to remove the dedup
1842                          *       registration because the area is still
1843                          *       allocated and the underlying DIO will
1844                          *       still be flushed.
1845                          */
1846                         if (dedup_off) {
1847                                 chain->bref.data_off = dedup_off;
1848                                 chain->bytes = 1 << (dedup_off &
1849                                                      HAMMER2_OFF_MASK_RADIX);
1850                                 chain->error = 0;
1851                                 atomic_clear_int(&chain->flags,
1852                                                  HAMMER2_CHAIN_MODIFIED);
1853                                 atomic_add_long(&hammer2_count_modified_chains,
1854                                                 -1);
1855                                 if (chain->pmp)
1856                                         hammer2_pfs_memory_wakeup(chain->pmp);
1857                                 hammer2_freemap_adjust(hmp, &chain->bref,
1858                                                 HAMMER2_FREEMAP_DORECOVER);
1859                                 atomic_set_int(&chain->flags,
1860                                                 HAMMER2_CHAIN_DEDUPABLE);
1861                         } else {
1862                                 error = hammer2_freemap_alloc(chain,
1863                                                               chain->bytes);
1864                                 atomic_clear_int(&chain->flags,
1865                                                 HAMMER2_CHAIN_DEDUPABLE);
1866                         }
1867                 }
1868         }
1869
1870         /*
1871          * Stop here if error.  We have to undo any flag bits we might
1872          * have set above.
1873          */
1874         if (error) {
1875                 if (setmodified) {
1876                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1877                         atomic_add_long(&hammer2_count_modified_chains, -1);
1878                         if (chain->pmp)
1879                                 hammer2_pfs_memory_wakeup(chain->pmp);
1880                 }
1881                 if (setupdate) {
1882                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1883                 }
1884                 return error;
1885         }
1886
1887         /*
1888          * Update mirror_tid and modify_tid.  modify_tid is only updated
1889          * if not passed as zero (during flushes, parent propagation passes
1890          * the value 0).
1891          *
1892          * NOTE: chain->pmp could be the device spmp.
1893          */
1894         chain->bref.mirror_tid = hmp->voldata.mirror_tid + 1;
1895         if (mtid)
1896                 chain->bref.modify_tid = mtid;
1897
1898         /*
1899          * Set BMAPUPD to tell the flush code that an existing blockmap entry
1900          * requires updating as well as to tell the delete code that the
1901          * chain's blockref might not exactly match (in terms of physical size
1902          * or block offset) the one in the parent's blocktable.  The base key
1903          * of course will still match.
1904          */
1905         if (chain->flags & HAMMER2_CHAIN_BMAPPED)
1906                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPUPD);
1907
1908         /*
1909          * Short-cut data blocks which the caller does not need an actual
1910          * data reference to (aka OPTDATA), as long as the chain does not
1911          * already have a data pointer to the data.  This generally means
1912          * that the modifications are being done via the logical buffer cache.
1913          * The INITIAL flag relates only to the device data buffer and thus
1914          * remains unchange in this situation.
1915          *
1916          * This code also handles bytes == 0 (most dirents).
1917          */
1918         if (chain->bref.type == HAMMER2_BREF_TYPE_DATA &&
1919             (flags & HAMMER2_MODIFY_OPTDATA) &&
1920             chain->data == NULL) {
1921                 KKASSERT(chain->dio == NULL);
1922                 goto skip2;
1923         }
1924
1925         /*
1926          * Clearing the INITIAL flag (for indirect blocks) indicates that
1927          * we've processed the uninitialized storage allocation.
1928          *
1929          * If this flag is already clear we are likely in a copy-on-write
1930          * situation but we have to be sure NOT to bzero the storage if
1931          * no data is present.
1932          */
1933         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1934                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1935                 wasinitial = 1;
1936         } else {
1937                 wasinitial = 0;
1938         }
1939
1940         /*
1941          * Instantiate data buffer and possibly execute COW operation
1942          */
1943         switch(chain->bref.type) {
1944         case HAMMER2_BREF_TYPE_VOLUME:
1945         case HAMMER2_BREF_TYPE_FREEMAP:
1946                 /*
1947                  * The data is embedded, no copy-on-write operation is
1948                  * needed.
1949                  */
1950                 KKASSERT(chain->dio == NULL);
1951                 break;
1952         case HAMMER2_BREF_TYPE_DIRENT:
1953                 /*
1954                  * The data might be fully embedded.
1955                  */
1956                 if (chain->bytes == 0) {
1957                         KKASSERT(chain->dio == NULL);
1958                         break;
1959                 }
1960                 /* fall through */
1961         case HAMMER2_BREF_TYPE_INODE:
1962         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1963         case HAMMER2_BREF_TYPE_DATA:
1964         case HAMMER2_BREF_TYPE_INDIRECT:
1965         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1966                 /*
1967                  * Perform the copy-on-write operation
1968                  *
1969                  * zero-fill or copy-on-write depending on whether
1970                  * chain->data exists or not and set the dirty state for
1971                  * the new buffer.  hammer2_io_new() will handle the
1972                  * zero-fill.
1973                  *
1974                  * If a dedup_off was supplied this is an existing block
1975                  * and no COW, copy, or further modification is required.
1976                  */
1977                 KKASSERT(chain != &hmp->vchain && chain != &hmp->fchain);
1978
1979                 if (wasinitial && dedup_off == 0) {
1980                         error = hammer2_io_new(hmp, chain->bref.type,
1981                                                chain->bref.data_off,
1982                                                chain->bytes, &dio);
1983                 } else {
1984                         error = hammer2_io_bread(hmp, chain->bref.type,
1985                                                  chain->bref.data_off,
1986                                                  chain->bytes, &dio);
1987                 }
1988                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1989
1990                 /*
1991                  * If an I/O error occurs make sure callers cannot accidently
1992                  * modify the old buffer's contents and corrupt the filesystem.
1993                  *
1994                  * NOTE: hammer2_io_data() call issues bkvasync()
1995                  */
1996                 if (error) {
1997                         kprintf("hammer2_chain_modify: hmp=%p I/O error\n",
1998                                 hmp);
1999                         chain->error = HAMMER2_ERROR_EIO;
2000                         hammer2_io_brelse(&dio);
2001                         hammer2_io_brelse(&chain->dio);
2002                         chain->data = NULL;
2003                         break;
2004                 }
2005                 chain->error = 0;
2006                 bdata = hammer2_io_data(dio, chain->bref.data_off);
2007
2008                 if (chain->data) {
2009                         /*
2010                          * COW (unless a dedup).
2011                          */
2012                         KKASSERT(chain->dio != NULL);
2013                         if (chain->data != (void *)bdata && dedup_off == 0) {
2014                                 bcopy(chain->data, bdata, chain->bytes);
2015                         }
2016                 } else if (wasinitial == 0) {
2017                         /*
2018                          * We have a problem.  We were asked to COW but
2019                          * we don't have any data to COW with!
2020                          */
2021                         panic("hammer2_chain_modify: having a COW %p\n",
2022                               chain);
2023                 }
2024
2025                 /*
2026                  * Retire the old buffer, replace with the new.  Dirty or
2027                  * redirty the new buffer.
2028                  *
2029                  * WARNING! The system buffer cache may have already flushed
2030                  *          the buffer, so we must be sure to [re]dirty it
2031                  *          for further modification.
2032                  *
2033                  *          If dedup_off was supplied, the caller is not
2034                  *          expected to make any further modification to the
2035                  *          buffer.
2036                  */
2037                 if (chain->dio)
2038                         hammer2_io_bqrelse(&chain->dio);
2039                 chain->data = (void *)bdata;
2040                 chain->dio = dio;
2041                 if (dedup_off == 0)
2042                         hammer2_io_setdirty(dio);
2043                 break;
2044         default:
2045                 panic("hammer2_chain_modify: illegal non-embedded type %d",
2046                       chain->bref.type);
2047                 break;
2048
2049         }
2050 skip2:
2051         /*
2052          * setflush on parent indicating that the parent must recurse down
2053          * to us.  Do not call on chain itself which might already have it
2054          * set.
2055          */
2056         if (chain->parent)
2057                 hammer2_chain_setflush(chain->parent);
2058         return (chain->error);
2059 }
2060
2061 /*
2062  * Modify the chain associated with an inode.
2063  */
2064 int
2065 hammer2_chain_modify_ip(hammer2_inode_t *ip, hammer2_chain_t *chain,
2066                         hammer2_tid_t mtid, int flags)
2067 {
2068         int error;
2069
2070         hammer2_inode_modify(ip);
2071         error = hammer2_chain_modify(chain, mtid, 0, flags);
2072
2073         return error;
2074 }
2075
2076 /*
2077  * Volume header data locks
2078  */
2079 void
2080 hammer2_voldata_lock(hammer2_dev_t *hmp)
2081 {
2082         lockmgr(&hmp->vollk, LK_EXCLUSIVE);
2083 }
2084
2085 void
2086 hammer2_voldata_unlock(hammer2_dev_t *hmp)
2087 {
2088         lockmgr(&hmp->vollk, LK_RELEASE);
2089 }
2090
2091 void
2092 hammer2_voldata_modify(hammer2_dev_t *hmp)
2093 {
2094         if ((hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) == 0) {
2095                 atomic_add_long(&hammer2_count_modified_chains, 1);
2096                 atomic_set_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
2097                 hammer2_pfs_memory_inc(hmp->vchain.pmp);
2098         }
2099 }
2100
2101 /*
2102  * This function returns the chain at the nearest key within the specified
2103  * range.  The returned chain will be referenced but not locked.
2104  *
2105  * This function will recurse through chain->rbtree as necessary and will
2106  * return a *key_nextp suitable for iteration.  *key_nextp is only set if
2107  * the iteration value is less than the current value of *key_nextp.
2108  *
2109  * The caller should use (*key_nextp) to calculate the actual range of
2110  * the returned element, which will be (key_beg to *key_nextp - 1), because
2111  * there might be another element which is superior to the returned element
2112  * and overlaps it.
2113  *
2114  * (*key_nextp) can be passed as key_beg in an iteration only while non-NULL
2115  * chains continue to be returned.  On EOF (*key_nextp) may overflow since
2116  * it will wind up being (key_end + 1).
2117  *
2118  * WARNING!  Must be called with child's spinlock held.  Spinlock remains
2119  *           held through the operation.
2120  */
2121 struct hammer2_chain_find_info {
2122         hammer2_chain_t         *best;
2123         hammer2_key_t           key_beg;
2124         hammer2_key_t           key_end;
2125         hammer2_key_t           key_next;
2126 };
2127
2128 static int hammer2_chain_find_cmp(hammer2_chain_t *child, void *data);
2129 static int hammer2_chain_find_callback(hammer2_chain_t *child, void *data);
2130
2131 static
2132 hammer2_chain_t *
2133 hammer2_chain_find(hammer2_chain_t *parent, hammer2_key_t *key_nextp,
2134                           hammer2_key_t key_beg, hammer2_key_t key_end)
2135 {
2136         struct hammer2_chain_find_info info;
2137
2138         info.best = NULL;
2139         info.key_beg = key_beg;
2140         info.key_end = key_end;
2141         info.key_next = *key_nextp;
2142
2143         RB_SCAN(hammer2_chain_tree, &parent->core.rbtree,
2144                 hammer2_chain_find_cmp, hammer2_chain_find_callback,
2145                 &info);
2146         *key_nextp = info.key_next;
2147 #if 0
2148         kprintf("chain_find %p %016jx:%016jx next=%016jx\n",
2149                 parent, key_beg, key_end, *key_nextp);
2150 #endif
2151
2152         return (info.best);
2153 }
2154
2155 static
2156 int
2157 hammer2_chain_find_cmp(hammer2_chain_t *child, void *data)
2158 {
2159         struct hammer2_chain_find_info *info = data;
2160         hammer2_key_t child_beg;
2161         hammer2_key_t child_end;
2162
2163         child_beg = child->bref.key;
2164         child_end = child_beg + ((hammer2_key_t)1 << child->bref.keybits) - 1;
2165
2166         if (child_end < info->key_beg)
2167                 return(-1);
2168         if (child_beg > info->key_end)
2169                 return(1);
2170         return(0);
2171 }
2172
2173 static
2174 int
2175 hammer2_chain_find_callback(hammer2_chain_t *child, void *data)
2176 {
2177         struct hammer2_chain_find_info *info = data;
2178         hammer2_chain_t *best;
2179         hammer2_key_t child_end;
2180
2181         /*
2182          * WARNING! Layerq is scanned forwards, exact matches should keep
2183          *          the existing info->best.
2184          */
2185         if ((best = info->best) == NULL) {
2186                 /*
2187                  * No previous best.  Assign best
2188                  */
2189                 info->best = child;
2190         } else if (best->bref.key <= info->key_beg &&
2191                    child->bref.key <= info->key_beg) {
2192                 /*
2193                  * Illegal overlap.
2194                  */
2195                 KKASSERT(0);
2196                 /*info->best = child;*/
2197         } else if (child->bref.key < best->bref.key) {
2198                 /*
2199                  * Child has a nearer key and best is not flush with key_beg.
2200                  * Set best to child.  Truncate key_next to the old best key.
2201                  */
2202                 info->best = child;
2203                 if (info->key_next > best->bref.key || info->key_next == 0)
2204                         info->key_next = best->bref.key;
2205         } else if (child->bref.key == best->bref.key) {
2206                 /*
2207                  * If our current best is flush with the child then this
2208                  * is an illegal overlap.
2209                  *
2210                  * key_next will automatically be limited to the smaller of
2211                  * the two end-points.
2212                  */
2213                 KKASSERT(0);
2214                 info->best = child;
2215         } else {
2216                 /*
2217                  * Keep the current best but truncate key_next to the child's
2218                  * base.
2219                  *
2220                  * key_next will also automatically be limited to the smaller
2221                  * of the two end-points (probably not necessary for this case
2222                  * but we do it anyway).
2223                  */
2224                 if (info->key_next > child->bref.key || info->key_next == 0)
2225                         info->key_next = child->bref.key;
2226         }
2227
2228         /*
2229          * Always truncate key_next based on child's end-of-range.
2230          */
2231         child_end = child->bref.key + ((hammer2_key_t)1 << child->bref.keybits);
2232         if (child_end && (info->key_next > child_end || info->key_next == 0))
2233                 info->key_next = child_end;
2234
2235         return(0);
2236 }
2237
2238 /*
2239  * Retrieve the specified chain from a media blockref, creating the
2240  * in-memory chain structure which reflects it.  The returned chain is
2241  * held and locked according to (how) (HAMMER2_RESOLVE_*).  The caller must
2242  * handle crc-checks and so forth, and should check chain->error before
2243  * assuming that the data is good.
2244  *
2245  * To handle insertion races pass the INSERT_RACE flag along with the
2246  * generation number of the core.  NULL will be returned if the generation
2247  * number changes before we have a chance to insert the chain.  Insert
2248  * races can occur because the parent might be held shared.
2249  *
2250  * Caller must hold the parent locked shared or exclusive since we may
2251  * need the parent's bref array to find our block.
2252  *
2253  * WARNING! chain->pmp is always set to NULL for any chain representing
2254  *          part of the super-root topology.
2255  */
2256 hammer2_chain_t *
2257 hammer2_chain_get(hammer2_chain_t *parent, int generation,
2258                   hammer2_blockref_t *bref, int how)
2259 {
2260         hammer2_dev_t *hmp = parent->hmp;
2261         hammer2_chain_t *chain;
2262         int error;
2263
2264         /*
2265          * Allocate a chain structure representing the existing media
2266          * entry.  Resulting chain has one ref and is not locked.
2267          */
2268         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
2269                 chain = hammer2_chain_alloc(hmp, NULL, bref);
2270         else
2271                 chain = hammer2_chain_alloc(hmp, parent->pmp, bref);
2272         /* ref'd chain returned */
2273
2274         /*
2275          * Flag that the chain is in the parent's blockmap so delete/flush
2276          * knows what to do with it.
2277          */
2278         atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
2279
2280         /*
2281          * chain must be locked to avoid unexpected ripouts
2282          */
2283         hammer2_chain_lock(chain, how);
2284
2285         /*
2286          * Link the chain into its parent.  A spinlock is required to safely
2287          * access the RBTREE, and it is possible to collide with another
2288          * hammer2_chain_get() operation because the caller might only hold
2289          * a shared lock on the parent.
2290          *
2291          * NOTE: Get races can occur quite often when we distribute
2292          *       asynchronous read-aheads across multiple threads.
2293          */
2294         KKASSERT(parent->refs > 0);
2295         error = hammer2_chain_insert(parent, chain,
2296                                      HAMMER2_CHAIN_INSERT_SPIN |
2297                                      HAMMER2_CHAIN_INSERT_RACE,
2298                                      generation);
2299         if (error) {
2300                 KKASSERT((chain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
2301                 /*kprintf("chain %p get race\n", chain);*/
2302                 hammer2_chain_unlock(chain);
2303                 hammer2_chain_drop(chain);
2304                 chain = NULL;
2305         } else {
2306                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
2307         }
2308
2309         /*
2310          * Return our new chain referenced but not locked, or NULL if
2311          * a race occurred.
2312          */
2313         return (chain);
2314 }
2315
2316 /*
2317  * Lookup initialization/completion API
2318  */
2319 hammer2_chain_t *
2320 hammer2_chain_lookup_init(hammer2_chain_t *parent, int flags)
2321 {
2322         hammer2_chain_ref(parent);
2323         if (flags & HAMMER2_LOOKUP_SHARED) {
2324                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS |
2325                                            HAMMER2_RESOLVE_SHARED);
2326         } else {
2327                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2328         }
2329         return (parent);
2330 }
2331
2332 void
2333 hammer2_chain_lookup_done(hammer2_chain_t *parent)
2334 {
2335         if (parent) {
2336                 hammer2_chain_unlock(parent);
2337                 hammer2_chain_drop(parent);
2338         }
2339 }
2340
2341 /*
2342  * Take the locked chain and return a locked parent.  The chain remains
2343  * locked on return, but may have to be temporarily unlocked to acquire
2344  * the parent.  Because of this, (chain) must be stable and cannot be
2345  * deleted while it was temporarily unlocked (typically means that (chain)
2346  * is an inode).
2347  *
2348  * Pass HAMMER2_RESOLVE_* flags in flags.
2349  *
2350  * This will work even if the chain is errored, and the caller can check
2351  * parent->error on return if desired since the parent will be locked.
2352  *
2353  * This function handles the lock order reversal.
2354  */
2355 hammer2_chain_t *
2356 hammer2_chain_getparent(hammer2_chain_t *chain, int flags)
2357 {
2358         hammer2_chain_t *parent;
2359
2360         /*
2361          * Be careful of order, chain must be unlocked before parent
2362          * is locked below to avoid a deadlock.  Try it trivially first.
2363          */
2364         parent = chain->parent;
2365         if (parent == NULL)
2366                 panic("hammer2_chain_getparent: no parent");
2367         hammer2_chain_ref(parent);
2368         if (hammer2_chain_lock(parent, flags|HAMMER2_RESOLVE_NONBLOCK) == 0)
2369                 return parent;
2370
2371         for (;;) {
2372                 hammer2_chain_unlock(chain);
2373                 hammer2_chain_lock(parent, flags);
2374                 hammer2_chain_lock(chain, flags);
2375
2376                 /*
2377                  * Parent relinking races are quite common.  We have to get
2378                  * it right or we will blow up the block table.
2379                  */
2380                 if (chain->parent == parent)
2381                         break;
2382                 hammer2_chain_unlock(parent);
2383                 hammer2_chain_drop(parent);
2384                 cpu_ccfence();
2385                 parent = chain->parent;
2386                 if (parent == NULL)
2387                         panic("hammer2_chain_getparent: no parent");
2388                 hammer2_chain_ref(parent);
2389         }
2390         return parent;
2391 }
2392
2393 /*
2394  * Take the locked chain and return a locked parent.  The chain is unlocked
2395  * and dropped.  *chainp is set to the returned parent as a convenience.
2396  * Pass HAMMER2_RESOLVE_* flags in flags.
2397  *
2398  * This will work even if the chain is errored, and the caller can check
2399  * parent->error on return if desired since the parent will be locked.
2400  *
2401  * The chain does NOT need to be stable.  We use a tracking structure
2402  * to track the expected parent if the chain is deleted out from under us.
2403  *
2404  * This function handles the lock order reversal.
2405  */
2406 hammer2_chain_t *
2407 hammer2_chain_repparent(hammer2_chain_t **chainp, int flags)
2408 {
2409         hammer2_chain_t *chain;
2410         hammer2_chain_t *parent;
2411         struct hammer2_reptrack reptrack;
2412         struct hammer2_reptrack **repp;
2413
2414         /*
2415          * Be careful of order, chain must be unlocked before parent
2416          * is locked below to avoid a deadlock.  Try it trivially first.
2417          */
2418         chain = *chainp;
2419         parent = chain->parent;
2420         if (parent == NULL) {
2421                 hammer2_spin_unex(&chain->core.spin);
2422                 panic("hammer2_chain_repparent: no parent");
2423         }
2424         hammer2_chain_ref(parent);
2425         if (hammer2_chain_lock(parent, flags|HAMMER2_RESOLVE_NONBLOCK) == 0) {
2426                 hammer2_chain_unlock(chain);
2427                 hammer2_chain_drop(chain);
2428                 *chainp = parent;
2429
2430                 return parent;
2431         }
2432
2433         /*
2434          * Ok, now it gets a bit nasty.  There are multiple situations where
2435          * the parent might be in the middle of a deletion, or where the child
2436          * (chain) might be deleted the instant we let go of its lock.
2437          * We can potentially end up in a no-win situation!
2438          *
2439          * In particular, the indirect_maintenance() case can cause these
2440          * situations.
2441          *
2442          * To deal with this we install a reptrack structure in the parent
2443          * This reptrack structure 'owns' the parent ref and will automatically
2444          * migrate to the parent's parent if the parent is deleted permanently.
2445          */
2446         hammer2_spin_init(&reptrack.spin, "h2reptrk");
2447         reptrack.chain = parent;
2448         hammer2_chain_ref(parent);              /* for the reptrack */
2449
2450         hammer2_spin_ex(&parent->core.spin);
2451         reptrack.next = parent->core.reptrack;
2452         parent->core.reptrack = &reptrack;
2453         hammer2_spin_unex(&parent->core.spin);
2454
2455         hammer2_chain_unlock(chain);
2456         hammer2_chain_drop(chain);
2457         chain = NULL;   /* gone */
2458
2459         /*
2460          * At the top of this loop, chain is gone and parent is refd both
2461          * by us explicitly AND via our reptrack.  We are attempting to
2462          * lock parent.
2463          */
2464         for (;;) {
2465                 hammer2_chain_lock(parent, flags);
2466
2467                 if (reptrack.chain == parent)
2468                         break;
2469                 hammer2_chain_unlock(parent);
2470                 hammer2_chain_drop(parent);
2471
2472                 kprintf("hammer2: debug REPTRACK %p->%p\n",
2473                         parent, reptrack.chain);
2474                 hammer2_spin_ex(&reptrack.spin);
2475                 parent = reptrack.chain;
2476                 hammer2_chain_ref(parent);
2477                 hammer2_spin_unex(&reptrack.spin);
2478         }
2479
2480         /*
2481          * Once parent is locked and matches our reptrack, our reptrack
2482          * will be stable and we have our parent.  We can unlink our
2483          * reptrack.
2484          *
2485          * WARNING!  Remember that the chain lock might be shared.  Chains
2486          *           locked shared have stable parent linkages.
2487          */
2488         hammer2_spin_ex(&parent->core.spin);
2489         repp = &parent->core.reptrack;
2490         while (*repp != &reptrack)
2491                 repp = &(*repp)->next;
2492         *repp = reptrack.next;
2493         hammer2_spin_unex(&parent->core.spin);
2494
2495         hammer2_chain_drop(parent);     /* reptrack ref */
2496         *chainp = parent;               /* return parent lock+ref */
2497
2498         return parent;
2499 }
2500
2501 /*
2502  * Dispose of any linked reptrack structures in (chain) by shifting them to
2503  * (parent).  Both (chain) and (parent) must be exclusively locked.
2504  *
2505  * This is interlocked against any children of (chain) on the other side.
2506  * No children so remain as-of when this is called so we can test
2507  * core.reptrack without holding the spin-lock.
2508  *
2509  * Used whenever the caller intends to permanently delete chains related
2510  * to topological recursions (BREF_TYPE_INDIRECT, BREF_TYPE_FREEMAP_NODE),
2511  * where the chains underneath the node being deleted are given a new parent
2512  * above the node being deleted.
2513  */
2514 static
2515 void
2516 hammer2_chain_repchange(hammer2_chain_t *parent, hammer2_chain_t *chain)
2517 {
2518         struct hammer2_reptrack *reptrack;
2519
2520         KKASSERT(chain->core.live_count == 0 && RB_EMPTY(&chain->core.rbtree));
2521         while (chain->core.reptrack) {
2522                 hammer2_spin_ex(&parent->core.spin);
2523                 hammer2_spin_ex(&chain->core.spin);
2524                 reptrack = chain->core.reptrack;
2525                 if (reptrack == NULL) {
2526                         hammer2_spin_unex(&chain->core.spin);
2527                         hammer2_spin_unex(&parent->core.spin);
2528                         break;
2529                 }
2530                 hammer2_spin_ex(&reptrack->spin);
2531                 chain->core.reptrack = reptrack->next;
2532                 reptrack->chain = parent;
2533                 reptrack->next = parent->core.reptrack;
2534                 parent->core.reptrack = reptrack;
2535                 hammer2_chain_ref(parent);              /* reptrack */
2536
2537                 hammer2_spin_unex(&chain->core.spin);
2538                 hammer2_spin_unex(&parent->core.spin);
2539                 kprintf("hammer2: debug repchange %p %p->%p\n",
2540                         reptrack, chain, parent);
2541                 hammer2_chain_drop(chain);              /* reptrack */
2542         }
2543 }
2544
2545 /*
2546  * Locate the first chain whos key range overlaps (key_beg, key_end) inclusive.
2547  * (*parentp) typically points to an inode but can also point to a related
2548  * indirect block and this function will recurse upwards and find the inode
2549  * or the nearest undeleted indirect block covering the key range.
2550  *
2551  * This function unconditionally sets *errorp, replacing any previous value.
2552  *
2553  * (*parentp) must be exclusive or shared locked (depending on flags) and
2554  * referenced and can be an inode or an existing indirect block within the
2555  * inode.
2556  *
2557  * If (*parent) is errored out, this function will not attempt to recurse
2558  * the radix tree and will return NULL along with an appropriate *errorp.
2559  * If NULL is returned and *errorp is 0, the requested lookup could not be
2560  * located.
2561  *
2562  * On return (*parentp) will be modified to point at the deepest parent chain
2563  * element encountered during the search, as a helper for an insertion or
2564  * deletion.
2565  *
2566  * The new (*parentp) will be locked shared or exclusive (depending on flags),
2567  * and referenced, and the old will be unlocked and dereferenced (no change
2568  * if they are both the same).  This is particularly important if the caller
2569  * wishes to insert a new chain, (*parentp) will be set properly even if NULL
2570  * is returned, as long as no error occurred.
2571  *
2572  * The matching chain will be returned locked according to flags.
2573  *
2574  * --
2575  *
2576  * NULL is returned if no match was found, but (*parentp) will still
2577  * potentially be adjusted.
2578  *
2579  * On return (*key_nextp) will point to an iterative value for key_beg.
2580  * (If NULL is returned (*key_nextp) is set to (key_end + 1)).
2581  *
2582  * This function will also recurse up the chain if the key is not within the
2583  * current parent's range.  (*parentp) can never be set to NULL.  An iteration
2584  * can simply allow (*parentp) to float inside the loop.
2585  *
2586  * NOTE!  chain->data is not always resolved.  By default it will not be
2587  *        resolved for BREF_TYPE_DATA, FREEMAP_NODE, or FREEMAP_LEAF.  Use
2588  *        HAMMER2_LOOKUP_ALWAYS to force resolution (but be careful w/
2589  *        BREF_TYPE_DATA as the device buffer can alias the logical file
2590  *        buffer).
2591  */
2592
2593 hammer2_chain_t *
2594 hammer2_chain_lookup(hammer2_chain_t **parentp, hammer2_key_t *key_nextp,
2595                      hammer2_key_t key_beg, hammer2_key_t key_end,
2596                      int *errorp, int flags)
2597 {
2598         hammer2_dev_t *hmp;
2599         hammer2_chain_t *parent;
2600         hammer2_chain_t *chain;
2601         hammer2_blockref_t *base;
2602         hammer2_blockref_t *bref;
2603         hammer2_blockref_t bcopy;
2604         hammer2_key_t scan_beg;
2605         hammer2_key_t scan_end;
2606         int count = 0;
2607         int how_always = HAMMER2_RESOLVE_ALWAYS;
2608         int how_maybe = HAMMER2_RESOLVE_MAYBE;
2609         int how;
2610         int generation;
2611         int maxloops = 300000;
2612         volatile hammer2_mtx_t save_mtx;
2613
2614         if (flags & HAMMER2_LOOKUP_ALWAYS) {
2615                 how_maybe = how_always;
2616                 how = HAMMER2_RESOLVE_ALWAYS;
2617         } else if (flags & HAMMER2_LOOKUP_NODATA) {
2618                 how = HAMMER2_RESOLVE_NEVER;
2619         } else {
2620                 how = HAMMER2_RESOLVE_MAYBE;
2621         }
2622         if (flags & HAMMER2_LOOKUP_SHARED) {
2623                 how_maybe |= HAMMER2_RESOLVE_SHARED;
2624                 how_always |= HAMMER2_RESOLVE_SHARED;
2625                 how |= HAMMER2_RESOLVE_SHARED;
2626         }
2627
2628         /*
2629          * Recurse (*parentp) upward if necessary until the parent completely
2630          * encloses the key range or we hit the inode.
2631          *
2632          * Handle races against the flusher deleting indirect nodes on its
2633          * way back up by continuing to recurse upward past the deletion.
2634          */
2635         parent = *parentp;
2636         hmp = parent->hmp;
2637         *errorp = 0;
2638
2639         while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
2640                parent->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2641                 scan_beg = parent->bref.key;
2642                 scan_end = scan_beg +
2643                            ((hammer2_key_t)1 << parent->bref.keybits) - 1;
2644                 if ((parent->flags & HAMMER2_CHAIN_DELETED) == 0) {
2645                         if (key_beg >= scan_beg && key_end <= scan_end)
2646                                 break;
2647                 }
2648                 parent = hammer2_chain_repparent(parentp, how_maybe);
2649         }
2650 again:
2651         if (--maxloops == 0)
2652                 panic("hammer2_chain_lookup: maxloops");
2653         /*
2654          * Locate the blockref array.  Currently we do a fully associative
2655          * search through the array.
2656          */
2657         switch(parent->bref.type) {
2658         case HAMMER2_BREF_TYPE_INODE:
2659                 /*
2660                  * Special shortcut for embedded data returns the inode
2661                  * itself.  Callers must detect this condition and access
2662                  * the embedded data (the strategy code does this for us).
2663                  *
2664                  * This is only applicable to regular files and softlinks.
2665                  *
2666                  * We need a second lock on parent.  Since we already have
2667                  * a lock we must pass LOCKAGAIN to prevent unexpected
2668                  * blocking (we don't want to block on a second shared
2669                  * ref if an exclusive lock is pending)
2670                  */
2671                 if (parent->data->ipdata.meta.op_flags &
2672                     HAMMER2_OPFLAG_DIRECTDATA) {
2673                         if (flags & HAMMER2_LOOKUP_NODIRECT) {
2674                                 chain = NULL;
2675                                 *key_nextp = key_end + 1;
2676                                 goto done;
2677                         }
2678                         hammer2_chain_ref(parent);
2679                         hammer2_chain_lock(parent, how_always |
2680                                                    HAMMER2_RESOLVE_LOCKAGAIN);
2681                         *key_nextp = key_end + 1;
2682                         return (parent);
2683                 }
2684                 base = &parent->data->ipdata.u.blockset.blockref[0];
2685                 count = HAMMER2_SET_COUNT;
2686                 break;
2687         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2688         case HAMMER2_BREF_TYPE_INDIRECT:
2689                 /*
2690                  * Handle MATCHIND on the parent
2691                  */
2692                 if (flags & HAMMER2_LOOKUP_MATCHIND) {
2693                         scan_beg = parent->bref.key;
2694                         scan_end = scan_beg +
2695                                ((hammer2_key_t)1 << parent->bref.keybits) - 1;
2696                         if (key_beg == scan_beg && key_end == scan_end) {
2697                                 chain = parent;
2698                                 hammer2_chain_ref(chain);
2699                                 hammer2_chain_lock(chain, how_maybe);
2700                                 *key_nextp = scan_end + 1;
2701                                 goto done;
2702                         }
2703                 }
2704
2705                 /*
2706                  * Optimize indirect blocks in the INITIAL state to avoid
2707                  * I/O.
2708                  */
2709                 if (parent->flags & HAMMER2_CHAIN_INITIAL) {
2710                         base = NULL;
2711                 } else {
2712                         if (parent->data == NULL) {
2713                                 kprintf("parent->data is NULL %p\n", parent);
2714                                 while (1)
2715                                         tsleep(parent, 0, "xxx", 0);
2716                         }
2717                         base = &parent->data->npdata[0];
2718                 }
2719                 count = parent->bytes / sizeof(hammer2_blockref_t);
2720                 break;
2721         case HAMMER2_BREF_TYPE_VOLUME:
2722                 base = &parent->data->voldata.sroot_blockset.blockref[0];
2723                 count = HAMMER2_SET_COUNT;
2724                 break;
2725         case HAMMER2_BREF_TYPE_FREEMAP:
2726                 base = &parent->data->blkset.blockref[0];
2727                 count = HAMMER2_SET_COUNT;
2728                 break;
2729         default:
2730                 kprintf("hammer2_chain_lookup: unrecognized "
2731                         "blockref(B) type: %d",
2732                         parent->bref.type);
2733                 while (1)
2734                         tsleep(&base, 0, "dead", 0);
2735                 panic("hammer2_chain_lookup: unrecognized "
2736                       "blockref(B) type: %d",
2737                       parent->bref.type);
2738                 base = NULL;    /* safety */
2739                 count = 0;      /* safety */
2740         }
2741
2742         /*
2743          * No lookup is possible if the parent is errored.  We delayed
2744          * this check as long as we could to ensure that the parent backup,
2745          * embedded data, and MATCHIND code could still execute.
2746          */
2747         if (parent->error) {
2748                 *errorp = parent->error;
2749                 return NULL;
2750         }
2751
2752         /*
2753          * Merged scan to find next candidate.
2754          *
2755          * hammer2_base_*() functions require the parent->core.live_* fields
2756          * to be synchronized.
2757          *
2758          * We need to hold the spinlock to access the block array and RB tree
2759          * and to interlock chain creation.
2760          */
2761         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
2762                 hammer2_chain_countbrefs(parent, base, count);
2763
2764         /*
2765          * Combined search
2766          */
2767         hammer2_spin_ex(&parent->core.spin);
2768         chain = hammer2_combined_find(parent, base, count,
2769                                       key_nextp,
2770                                       key_beg, key_end,
2771                                       &bref);
2772         generation = parent->core.generation;
2773
2774         /*
2775          * Exhausted parent chain, iterate.
2776          */
2777         if (bref == NULL) {
2778                 KKASSERT(chain == NULL);
2779                 hammer2_spin_unex(&parent->core.spin);
2780                 if (key_beg == key_end) /* short cut single-key case */
2781                         return (NULL);
2782
2783                 /*
2784                  * Stop if we reached the end of the iteration.
2785                  */
2786                 if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT &&
2787                     parent->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2788                         return (NULL);
2789                 }
2790
2791                 /*
2792                  * Calculate next key, stop if we reached the end of the
2793                  * iteration, otherwise go up one level and loop.
2794                  */
2795                 key_beg = parent->bref.key +
2796                           ((hammer2_key_t)1 << parent->bref.keybits);
2797                 if (key_beg == 0 || key_beg > key_end)
2798                         return (NULL);
2799                 parent = hammer2_chain_repparent(parentp, how_maybe);
2800                 goto again;
2801         }
2802
2803         /*
2804          * Selected from blockref or in-memory chain.
2805          */
2806         bcopy = *bref;
2807         if (chain == NULL) {
2808                 hammer2_spin_unex(&parent->core.spin);
2809                 if (bcopy.type == HAMMER2_BREF_TYPE_INDIRECT ||
2810                     bcopy.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2811                         chain = hammer2_chain_get(parent, generation,
2812                                                   &bcopy, how_maybe);
2813                 } else {
2814                         chain = hammer2_chain_get(parent, generation,
2815                                                   &bcopy, how);
2816                 }
2817                 if (chain == NULL)
2818                         goto again;
2819         } else {
2820                 hammer2_chain_ref(chain);
2821                 hammer2_spin_unex(&parent->core.spin);
2822
2823                 /*
2824                  * chain is referenced but not locked.  We must lock the
2825                  * chain to obtain definitive state.
2826                  */
2827                 if (bcopy.type == HAMMER2_BREF_TYPE_INDIRECT ||
2828                     bcopy.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2829                         hammer2_chain_lock(chain, how_maybe);
2830                 } else {
2831                         hammer2_chain_lock(chain, how);
2832                 }
2833                 KKASSERT(chain->parent == parent);
2834         }
2835         if (bcmp(&bcopy, &chain->bref, sizeof(bcopy)) ||
2836             chain->parent != parent) {
2837                 hammer2_chain_unlock(chain);
2838                 hammer2_chain_drop(chain);
2839                 chain = NULL;   /* SAFETY */
2840                 goto again;
2841         }
2842
2843
2844         /*
2845          * Skip deleted chains (XXX cache 'i' end-of-block-array? XXX)
2846          *
2847          * NOTE: Chain's key range is not relevant as there might be
2848          *       one-offs within the range that are not deleted.
2849          *
2850          * NOTE: Lookups can race delete-duplicate because
2851          *       delete-duplicate does not lock the parent's core
2852          *       (they just use the spinlock on the core).
2853          */
2854         if (chain->flags & HAMMER2_CHAIN_DELETED) {
2855                 kprintf("skip deleted chain %016jx.%02x key=%016jx\n",
2856                         chain->bref.data_off, chain->bref.type,
2857                         chain->bref.key);
2858                 hammer2_chain_unlock(chain);
2859                 hammer2_chain_drop(chain);
2860                 chain = NULL;   /* SAFETY */
2861                 key_beg = *key_nextp;
2862                 if (key_beg == 0 || key_beg > key_end)
2863                         return(NULL);
2864                 goto again;
2865         }
2866
2867         /*
2868          * If the chain element is an indirect block it becomes the new
2869          * parent and we loop on it.  We must maintain our top-down locks
2870          * to prevent the flusher from interfering (i.e. doing a
2871          * delete-duplicate and leaving us recursing down a deleted chain).
2872          *
2873          * The parent always has to be locked with at least RESOLVE_MAYBE
2874          * so we can access its data.  It might need a fixup if the caller
2875          * passed incompatible flags.  Be careful not to cause a deadlock
2876          * as a data-load requires an exclusive lock.
2877          *
2878          * If HAMMER2_LOOKUP_MATCHIND is set and the indirect block's key
2879          * range is within the requested key range we return the indirect
2880          * block and do NOT loop.  This is usually only used to acquire
2881          * freemap nodes.
2882          */
2883         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
2884             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2885                 save_mtx = parent->lock;
2886                 hammer2_chain_unlock(parent);
2887                 hammer2_chain_drop(parent);
2888                 *parentp = parent = chain;
2889                 chain = NULL;   /* SAFETY */
2890                 goto again;
2891         }
2892 done:
2893         /*
2894          * All done, return the locked chain.
2895          *
2896          * If the caller does not want a locked chain, replace the lock with
2897          * a ref.  Perhaps this can eventually be optimized to not obtain the
2898          * lock in the first place for situations where the data does not
2899          * need to be resolved.
2900          *
2901          * NOTE! A chain->error must be tested by the caller upon return.
2902          *       *errorp is only set based on issues which occur while
2903          *       trying to reach the chain.
2904          */
2905         return (chain);
2906 }
2907
2908 /*
2909  * After having issued a lookup we can iterate all matching keys.
2910  *
2911  * If chain is non-NULL we continue the iteration from just after it's index.
2912  *
2913  * If chain is NULL we assume the parent was exhausted and continue the
2914  * iteration at the next parent.
2915  *
2916  * If a fatal error occurs (typically an I/O error), a dummy chain is
2917  * returned with chain->error and error-identifying information set.  This
2918  * chain will assert if you try to do anything fancy with it.
2919  *
2920  * XXX Depending on where the error occurs we should allow continued iteration.
2921  *
2922  * parent must be locked on entry and remains locked throughout.  chain's
2923  * lock status must match flags.  Chain is always at least referenced.
2924  *
2925  * WARNING!  The MATCHIND flag does not apply to this function.
2926  */
2927 hammer2_chain_t *
2928 hammer2_chain_next(hammer2_chain_t **parentp, hammer2_chain_t *chain,
2929                    hammer2_key_t *key_nextp,
2930                    hammer2_key_t key_beg, hammer2_key_t key_end,
2931                    int *errorp, int flags)
2932 {
2933         hammer2_chain_t *parent;
2934         int how_maybe;
2935
2936         /*
2937          * Calculate locking flags for upward recursion.
2938          */
2939         how_maybe = HAMMER2_RESOLVE_MAYBE;
2940         if (flags & HAMMER2_LOOKUP_SHARED)
2941                 how_maybe |= HAMMER2_RESOLVE_SHARED;
2942
2943         parent = *parentp;
2944         *errorp = 0;
2945
2946         /*
2947          * Calculate the next index and recalculate the parent if necessary.
2948          */
2949         if (chain) {
2950                 key_beg = chain->bref.key +
2951                           ((hammer2_key_t)1 << chain->bref.keybits);
2952                 hammer2_chain_unlock(chain);
2953                 hammer2_chain_drop(chain);
2954
2955                 /*
2956                  * chain invalid past this point, but we can still do a
2957                  * pointer comparison w/parent.
2958                  *
2959                  * Any scan where the lookup returned degenerate data embedded
2960                  * in the inode has an invalid index and must terminate.
2961                  */
2962                 if (chain == parent)
2963                         return(NULL);
2964                 if (key_beg == 0 || key_beg > key_end)
2965                         return(NULL);
2966                 chain = NULL;
2967         } else if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT &&
2968                    parent->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2969                 /*
2970                  * We reached the end of the iteration.
2971                  */
2972                 return (NULL);
2973         } else {
2974                 /*
2975                  * Continue iteration with next parent unless the current
2976                  * parent covers the range.
2977                  *
2978                  * (This also handles the case of a deleted, empty indirect
2979                  * node).
2980                  */
2981                 key_beg = parent->bref.key +
2982                           ((hammer2_key_t)1 << parent->bref.keybits);
2983                 if (key_beg == 0 || key_beg > key_end)
2984                         return (NULL);
2985                 parent = hammer2_chain_repparent(parentp, how_maybe);
2986         }
2987
2988         /*
2989          * And execute
2990          */
2991         return (hammer2_chain_lookup(parentp, key_nextp,
2992                                      key_beg, key_end,
2993                                      errorp, flags));
2994 }
2995
2996 /*
2997  * Caller wishes to iterate chains under parent, loading new chains into
2998  * chainp.  Caller must initialize *chainp to NULL and *firstp to 1, and
2999  * then call hammer2_chain_scan() repeatedly until a non-zero return.
3000  * During the scan, *firstp will be set to 0 and (*chainp) will be replaced
3001  * with the returned chain for the scan.  The returned *chainp will be
3002  * locked and referenced.  Any prior contents will be unlocked and dropped.
3003  *
3004  * Caller should check the return value.  A normal scan EOF will return
3005  * exactly HAMMER2_ERROR_EOF.  Any other non-zero value indicates an
3006  * error trying to access parent data.  Any error in the returned chain
3007  * must be tested separately by the caller.
3008  *
3009  * (*chainp) is dropped on each scan, but will only be set if the returned
3010  * element itself can recurse.  Leaf elements are NOT resolved, loaded, or
3011  * returned via *chainp.  The caller will get their bref only.
3012  *
3013  * The raw scan function is similar to lookup/next but does not seek to a key.
3014  * Blockrefs are iterated via first_bref = (parent, NULL) and
3015  * next_chain = (parent, bref).
3016  *
3017  * The passed-in parent must be locked and its data resolved.  The function
3018  * nominally returns a locked and referenced *chainp != NULL for chains
3019  * the caller might need to recurse on (and will dipose of any *chainp passed
3020  * in).  The caller must check the chain->bref.type either way.
3021  */
3022 int
3023 hammer2_chain_scan(hammer2_chain_t *parent, hammer2_chain_t **chainp,
3024                    hammer2_blockref_t *bref, int *firstp,
3025                    int flags)
3026 {
3027         hammer2_dev_t *hmp;
3028         hammer2_blockref_t *base;
3029         hammer2_blockref_t *bref_ptr;
3030         hammer2_key_t key;
3031         hammer2_key_t next_key;
3032         hammer2_chain_t *chain = NULL;
3033         int count = 0;
3034         int how_always = HAMMER2_RESOLVE_ALWAYS;
3035         int how_maybe = HAMMER2_RESOLVE_MAYBE;
3036         int how;
3037         int generation;
3038         int maxloops = 300000;
3039         int error;
3040
3041         hmp = parent->hmp;
3042         error = 0;
3043
3044         /*
3045          * Scan flags borrowed from lookup.
3046          */
3047         if (flags & HAMMER2_LOOKUP_ALWAYS) {
3048                 how_maybe = how_always;
3049                 how = HAMMER2_RESOLVE_ALWAYS;
3050         } else if (flags & HAMMER2_LOOKUP_NODATA) {
3051                 how = HAMMER2_RESOLVE_NEVER;
3052         } else {
3053                 how = HAMMER2_RESOLVE_MAYBE;
3054         }
3055         if (flags & HAMMER2_LOOKUP_SHARED) {
3056                 how_maybe |= HAMMER2_RESOLVE_SHARED;
3057                 how_always |= HAMMER2_RESOLVE_SHARED;
3058                 how |= HAMMER2_RESOLVE_SHARED;
3059         }
3060
3061         /*
3062          * Calculate key to locate first/next element, unlocking the previous
3063          * element as we go.  Be careful, the key calculation can overflow.
3064          *
3065          * (also reset bref to NULL)
3066          */
3067         if (*firstp) {
3068                 key = 0;
3069                 *firstp = 0;
3070         } else {
3071                 key = bref->key + ((hammer2_key_t)1 << bref->keybits);
3072                 if ((chain = *chainp) != NULL) {
3073                         *chainp = NULL;
3074                         hammer2_chain_unlock(chain);
3075                         hammer2_chain_drop(chain);
3076                         chain = NULL;
3077                 }
3078                 if (key == 0) {
3079                         error |= HAMMER2_ERROR_EOF;
3080                         goto done;
3081                 }
3082         }
3083
3084 again:
3085         if (parent->error) {
3086                 error = parent->error;
3087                 goto done;
3088         }
3089         if (--maxloops == 0)
3090                 panic("hammer2_chain_scan: maxloops");
3091
3092         /*
3093          * Locate the blockref array.  Currently we do a fully associative
3094          * search through the array.
3095          */
3096         switch(parent->bref.type) {
3097         case HAMMER2_BREF_TYPE_INODE:
3098                 /*
3099                  * An inode with embedded data has no sub-chains.
3100                  *
3101                  * WARNING! Bulk scan code may pass a static chain marked
3102                  *          as BREF_TYPE_INODE with a copy of the volume
3103                  *          root blockset to snapshot the volume.
3104                  */
3105                 if (parent->data->ipdata.meta.op_flags &
3106                     HAMMER2_OPFLAG_DIRECTDATA) {
3107                         error |= HAMMER2_ERROR_EOF;
3108                         goto done;
3109                 }
3110                 base = &parent->data->ipdata.u.blockset.blockref[0];
3111                 count = HAMMER2_SET_COUNT;
3112                 break;
3113         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3114         case HAMMER2_BREF_TYPE_INDIRECT:
3115                 /*
3116                  * Optimize indirect blocks in the INITIAL state to avoid
3117                  * I/O.
3118                  */
3119                 if (parent->flags & HAMMER2_CHAIN_INITIAL) {
3120                         base = NULL;
3121                 } else {
3122                         if (parent->data == NULL)
3123                                 panic("parent->data is NULL");
3124                         base = &parent->data->npdata[0];
3125                 }
3126                 count = parent->bytes / sizeof(hammer2_blockref_t);
3127                 break;
3128         case HAMMER2_BREF_TYPE_VOLUME:
3129                 base = &parent->data->voldata.sroot_blockset.blockref[0];
3130                 count = HAMMER2_SET_COUNT;
3131                 break;
3132         case HAMMER2_BREF_TYPE_FREEMAP:
3133                 base = &parent->data->blkset.blockref[0];
3134                 count = HAMMER2_SET_COUNT;
3135                 break;
3136         default:
3137                 panic("hammer2_chain_lookup: unrecognized blockref type: %d",
3138                       parent->bref.type);
3139                 base = NULL;    /* safety */
3140                 count = 0;      /* safety */
3141         }
3142
3143         /*
3144          * Merged scan to find next candidate.
3145          *
3146          * hammer2_base_*() functions require the parent->core.live_* fields
3147          * to be synchronized.
3148          *
3149          * We need to hold the spinlock to access the block array and RB tree
3150          * and to interlock chain creation.
3151          */
3152         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
3153                 hammer2_chain_countbrefs(parent, base, count);
3154
3155         next_key = 0;
3156         bref_ptr = NULL;
3157         hammer2_spin_ex(&parent->core.spin);
3158         chain = hammer2_combined_find(parent, base, count,
3159                                       &next_key,
3160                                       key, HAMMER2_KEY_MAX,
3161                                       &bref_ptr);
3162         generation = parent->core.generation;
3163
3164         /*
3165          * Exhausted parent chain, we're done.
3166          */
3167         if (bref_ptr == NULL) {
3168                 hammer2_spin_unex(&parent->core.spin);
3169                 KKASSERT(chain == NULL);
3170                 error |= HAMMER2_ERROR_EOF;
3171                 goto done;
3172         }
3173
3174         /*
3175          * Copy into the supplied stack-based blockref.
3176          */
3177         *bref = *bref_ptr;
3178
3179         /*
3180          * Selected from blockref or in-memory chain.
3181          */
3182         if (chain == NULL) {
3183                 switch(bref->type) {
3184                 case HAMMER2_BREF_TYPE_INODE:
3185                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3186                 case HAMMER2_BREF_TYPE_INDIRECT:
3187                 case HAMMER2_BREF_TYPE_VOLUME:
3188                 case HAMMER2_BREF_TYPE_FREEMAP:
3189                         /*
3190                          * Recursion, always get the chain
3191                          */
3192                         hammer2_spin_unex(&parent->core.spin);
3193                         chain = hammer2_chain_get(parent, generation,
3194                                                   bref, how);
3195                         if (chain == NULL)
3196                                 goto again;
3197                         break;
3198                 default:
3199                         /*
3200                          * No recursion, do not waste time instantiating
3201                          * a chain, just iterate using the bref.
3202                          */
3203                         hammer2_spin_unex(&parent->core.spin);
3204                         break;
3205                 }
3206         } else {
3207                 /*
3208                  * Recursion or not we need the chain in order to supply
3209                  * the bref.
3210                  */
3211                 hammer2_chain_ref(chain);
3212                 hammer2_spin_unex(&parent->core.spin);
3213                 hammer2_chain_lock(chain, how);
3214         }
3215         if (chain &&
3216             (bcmp(bref, &chain->bref, sizeof(*bref)) ||
3217              chain->parent != parent)) {
3218                 hammer2_chain_unlock(chain);
3219                 hammer2_chain_drop(chain);
3220                 chain = NULL;
3221                 goto again;
3222         }
3223
3224         /*
3225          * Skip deleted chains (XXX cache 'i' end-of-block-array? XXX)
3226          *
3227          * NOTE: chain's key range is not relevant as there might be
3228          *       one-offs within the range that are not deleted.
3229          *
3230          * NOTE: XXX this could create problems with scans used in
3231          *       situations other than mount-time recovery.
3232          *
3233          * NOTE: Lookups can race delete-duplicate because
3234          *       delete-duplicate does not lock the parent's core
3235          *       (they just use the spinlock on the core).
3236          */
3237         if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
3238                 hammer2_chain_unlock(chain);
3239                 hammer2_chain_drop(chain);
3240                 chain = NULL;
3241
3242                 key = next_key;
3243                 if (key == 0) {
3244                         error |= HAMMER2_ERROR_EOF;
3245                         goto done;
3246                 }
3247                 goto again;
3248         }
3249
3250 done:
3251         /*
3252          * All done, return the bref or NULL, supply chain if necessary.
3253          */
3254         if (chain)
3255                 *chainp = chain;
3256         return (error);
3257 }
3258
3259 /*
3260  * Create and return a new hammer2 system memory structure of the specified
3261  * key, type and size and insert it under (*parentp).  This is a full
3262  * insertion, based on the supplied key/keybits, and may involve creating
3263  * indirect blocks and moving other chains around via delete/duplicate.
3264  *
3265  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (*parentp) TO THE INSERTION
3266  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
3267  * FULL.  This typically means that the caller is creating the chain after
3268  * doing a hammer2_chain_lookup().
3269  *
3270  * (*parentp) must be exclusive locked and may be replaced on return
3271  * depending on how much work the function had to do.
3272  *
3273  * (*parentp) must not be errored or this function will assert.
3274  *
3275  * (*chainp) usually starts out NULL and returns the newly created chain,
3276  * but if the caller desires the caller may allocate a disconnected chain
3277  * and pass it in instead.
3278  *
3279  * This function should NOT be used to insert INDIRECT blocks.  It is
3280  * typically used to create/insert inodes and data blocks.
3281  *
3282  * Caller must pass-in an exclusively locked parent the new chain is to
3283  * be inserted under, and optionally pass-in a disconnected, exclusively
3284  * locked chain to insert (else we create a new chain).  The function will
3285  * adjust (*parentp) as necessary, create or connect the chain, and
3286  * return an exclusively locked chain in *chainp.
3287  *
3288  * When creating a PFSROOT inode under the super-root, pmp is typically NULL
3289  * and will be reassigned.
3290  *
3291  * NOTE: returns HAMMER_ERROR_* flags
3292  */
3293 int
3294 hammer2_chain_create(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
3295                      hammer2_pfs_t *pmp, int methods,
3296                      hammer2_key_t key, int keybits, int type, size_t bytes,
3297                      hammer2_tid_t mtid, hammer2_off_t dedup_off, int flags)
3298 {
3299         hammer2_dev_t *hmp;
3300         hammer2_chain_t *chain;
3301         hammer2_chain_t *parent;
3302         hammer2_blockref_t *base;
3303         hammer2_blockref_t dummy;
3304         int allocated = 0;
3305         int error = 0;
3306         int count;
3307         int maxloops = 300000;
3308
3309         /*
3310          * Topology may be crossing a PFS boundary.
3311          */
3312         parent = *parentp;
3313         KKASSERT(hammer2_mtx_owned(&parent->lock));
3314         KKASSERT(parent->error == 0);
3315         hmp = parent->hmp;
3316         chain = *chainp;
3317
3318         if (chain == NULL) {
3319                 /*
3320                  * First allocate media space and construct the dummy bref,
3321                  * then allocate the in-memory chain structure.  Set the
3322                  * INITIAL flag for fresh chains which do not have embedded
3323                  * data.
3324                  *
3325                  * XXX for now set the check mode of the child based on
3326                  *     the parent or, if the parent is an inode, the
3327                  *     specification in the inode.
3328                  */
3329                 bzero(&dummy, sizeof(dummy));
3330                 dummy.type = type;
3331                 dummy.key = key;
3332                 dummy.keybits = keybits;
3333                 dummy.data_off = hammer2_getradix(bytes);
3334
3335                 /*
3336                  * Inherit methods from parent by default.  Primarily used
3337                  * for BREF_TYPE_DATA.  Non-data types *must* be set to
3338                  * a non-NONE check algorithm.
3339                  */
3340                 if (methods == -1)
3341                         dummy.methods = parent->bref.methods;
3342                 else
3343                         dummy.methods = (uint8_t)methods;
3344
3345                 if (type != HAMMER2_BREF_TYPE_DATA &&
3346                     HAMMER2_DEC_CHECK(dummy.methods) == HAMMER2_CHECK_NONE) {
3347                         dummy.methods |=
3348                                 HAMMER2_ENC_CHECK(HAMMER2_CHECK_DEFAULT);
3349                 }
3350
3351                 chain = hammer2_chain_alloc(hmp, pmp, &dummy);
3352
3353                 /*
3354                  * Lock the chain manually, chain_lock will load the chain
3355                  * which we do NOT want to do.  (note: chain->refs is set
3356                  * to 1 by chain_alloc() for us, but lockcnt is not).
3357                  */
3358                 chain->lockcnt = 1;
3359                 hammer2_mtx_ex(&chain->lock);
3360                 allocated = 1;
3361                 ++curthread->td_tracker;
3362
3363                 /*
3364                  * Set INITIAL to optimize I/O.  The flag will generally be
3365                  * processed when we call hammer2_chain_modify().
3366                  *
3367                  * Recalculate bytes to reflect the actual media block
3368                  * allocation.  Handle special case radix 0 == 0 bytes.
3369                  */
3370                 bytes = (size_t)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
3371                 if (bytes)
3372                         bytes = (hammer2_off_t)1 << bytes;
3373                 chain->bytes = bytes;
3374
3375                 switch(type) {
3376                 case HAMMER2_BREF_TYPE_VOLUME:
3377                 case HAMMER2_BREF_TYPE_FREEMAP:
3378                         panic("hammer2_chain_create: called with volume type");
3379                         break;
3380                 case HAMMER2_BREF_TYPE_INDIRECT:
3381                         panic("hammer2_chain_create: cannot be used to"
3382                               "create indirect block");
3383                         break;
3384                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3385                         panic("hammer2_chain_create: cannot be used to"
3386                               "create freemap root or node");
3387                         break;
3388                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3389                         KKASSERT(bytes == sizeof(chain->data->bmdata));
3390                         /* fall through */
3391                 case HAMMER2_BREF_TYPE_DIRENT:
3392                 case HAMMER2_BREF_TYPE_INODE:
3393                 case HAMMER2_BREF_TYPE_DATA:
3394                 default:
3395                         /*
3396                          * leave chain->data NULL, set INITIAL
3397                          */
3398                         KKASSERT(chain->data == NULL);
3399                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
3400                         break;
3401                 }
3402         } else {
3403                 /*
3404                  * We are reattaching a previously deleted chain, possibly
3405                  * under a new parent and possibly with a new key/keybits.
3406                  * The chain does not have to be in a modified state.  The
3407                  * UPDATE flag will be set later on in this routine.
3408                  *
3409                  * Do NOT mess with the current state of the INITIAL flag.
3410                  */
3411                 chain->bref.key = key;
3412                 chain->bref.keybits = keybits;
3413                 if (chain->flags & HAMMER2_CHAIN_DELETED)
3414                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3415                 KKASSERT(chain->parent == NULL);
3416         }
3417
3418         /*
3419          * Set the appropriate bref flag if requested.
3420          *
3421          * NOTE! Callers can call this function to move chains without
3422          *       knowing about special flags, so don't clear bref flags
3423          *       here!
3424          */
3425         if (flags & HAMMER2_INSERT_PFSROOT)
3426                 chain->bref.flags |= HAMMER2_BREF_FLAG_PFSROOT;
3427
3428         /*
3429          * Calculate how many entries we have in the blockref array and
3430          * determine if an indirect block is required.
3431          */
3432 again:
3433         if (--maxloops == 0)
3434                 panic("hammer2_chain_create: maxloops");
3435
3436         switch(parent->bref.type) {
3437         case HAMMER2_BREF_TYPE_INODE:
3438                 if ((parent->data->ipdata.meta.op_flags &
3439                      HAMMER2_OPFLAG_DIRECTDATA) != 0) {
3440                         kprintf("hammer2: parent set for direct-data! "
3441                                 "pkey=%016jx ckey=%016jx\n",
3442                                 parent->bref.key,
3443                                 chain->bref.key);
3444                 }
3445                 KKASSERT((parent->data->ipdata.meta.op_flags &
3446                           HAMMER2_OPFLAG_DIRECTDATA) == 0);
3447                 KKASSERT(parent->data != NULL);
3448                 base = &parent->data->ipdata.u.blockset.blockref[0];
3449                 count = HAMMER2_SET_COUNT;
3450                 break;
3451         case HAMMER2_BREF_TYPE_INDIRECT:
3452         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3453                 if (parent->flags & HAMMER2_CHAIN_INITIAL)
3454                         base = NULL;
3455                 else
3456                         base = &parent->data->npdata[0];
3457                 count = parent->bytes / sizeof(hammer2_blockref_t);
3458                 break;
3459         case HAMMER2_BREF_TYPE_VOLUME:
3460                 KKASSERT(parent->data != NULL);
3461                 base = &parent->data->voldata.sroot_blockset.blockref[0];
3462                 count = HAMMER2_SET_COUNT;
3463                 break;
3464         case HAMMER2_BREF_TYPE_FREEMAP:
3465                 KKASSERT(parent->data != NULL);
3466                 base = &parent->data->blkset.blockref[0];
3467                 count = HAMMER2_SET_COUNT;
3468                 break;
3469         default:
3470                 panic("hammer2_chain_create: unrecognized blockref type: %d",
3471                       parent->bref.type);
3472                 base = NULL;
3473                 count = 0;
3474                 break;
3475         }
3476
3477         /*
3478          * Make sure we've counted the brefs
3479          */
3480         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
3481                 hammer2_chain_countbrefs(parent, base, count);
3482
3483         KASSERT(parent->core.live_count >= 0 &&
3484                 parent->core.live_count <= count,
3485                 ("bad live_count %d/%d (%02x, %d)",
3486                         parent->core.live_count, count,
3487                         parent->bref.type, parent->bytes));
3488
3489         /*
3490          * If no free blockref could be found we must create an indirect
3491          * block and move a number of blockrefs into it.  With the parent
3492          * locked we can safely lock each child in order to delete+duplicate
3493          * it without causing a deadlock.
3494          *
3495          * This may return the new indirect block or the old parent depending
3496          * on where the key falls.  NULL is returned on error.
3497          */
3498         if (parent->core.live_count == count) {
3499                 hammer2_chain_t *nparent;
3500
3501                 KKASSERT((flags & HAMMER2_INSERT_SAMEPARENT) == 0);
3502
3503                 nparent = hammer2_chain_create_indirect(parent, key, keybits,
3504                                                         mtid, type, &error);
3505                 if (nparent == NULL) {
3506                         if (allocated)
3507                                 hammer2_chain_drop(chain);
3508                         chain = NULL;
3509                         goto done;
3510                 }
3511                 if (parent != nparent) {
3512                         hammer2_chain_unlock(parent);
3513                         hammer2_chain_drop(parent);
3514                         parent = *parentp = nparent;
3515                 }
3516                 goto again;
3517         }
3518
3519         if (chain->flags & HAMMER2_CHAIN_DELETED)
3520                 kprintf("Inserting deleted chain @%016jx\n",
3521                         chain->bref.key);
3522
3523         /*
3524          * Link the chain into its parent.
3525          */
3526         if (chain->parent != NULL)
3527                 panic("hammer2: hammer2_chain_create: chain already connected");
3528         KKASSERT(chain->parent == NULL);
3529         KKASSERT(parent->core.live_count < count);
3530         hammer2_chain_insert(parent, chain,
3531                              HAMMER2_CHAIN_INSERT_SPIN |
3532                              HAMMER2_CHAIN_INSERT_LIVE,
3533                              0);
3534
3535         if (allocated) {
3536                 /*
3537                  * Mark the newly created chain modified.  This will cause
3538                  * UPDATE to be set and process the INITIAL flag.
3539                  *
3540                  * Device buffers are not instantiated for DATA elements
3541                  * as these are handled by logical buffers.
3542                  *
3543                  * Indirect and freemap node indirect blocks are handled
3544                  * by hammer2_chain_create_indirect() and not by this
3545                  * function.
3546                  *
3547                  * Data for all other bref types is expected to be
3548                  * instantiated (INODE, LEAF).
3549                  */
3550                 switch(chain->bref.type) {
3551                 case HAMMER2_BREF_TYPE_DATA:
3552                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3553                 case HAMMER2_BREF_TYPE_DIRENT:
3554                 case HAMMER2_BREF_TYPE_INODE:
3555                         error = hammer2_chain_modify(chain, mtid, dedup_off,
3556                                                      HAMMER2_MODIFY_OPTDATA);
3557                         break;
3558                 default:
3559                         /*
3560                          * Remaining types are not supported by this function.
3561                          * In particular, INDIRECT and LEAF_NODE types are
3562                          * handled by create_indirect().
3563                          */
3564                         panic("hammer2_chain_create: bad type: %d",
3565                               chain->bref.type);
3566                         /* NOT REACHED */
3567                         break;
3568                 }
3569         } else {
3570                 /*
3571                  * When reconnecting a chain we must set UPDATE and
3572                  * setflush so the flush recognizes that it must update
3573                  * the bref in the parent.
3574                  */
3575                 if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0)
3576                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
3577         }
3578
3579         /*
3580          * We must setflush(parent) to ensure that it recurses through to
3581          * chain.  setflush(chain) might not work because ONFLUSH is possibly
3582          * already set in the chain (so it won't recurse up to set it in the
3583          * parent).
3584          */
3585         hammer2_chain_setflush(parent);
3586
3587 done:
3588         *chainp = chain;
3589
3590         return (error);
3591 }
3592
3593 /*
3594  * Move the chain from its old parent to a new parent.  The chain must have
3595  * already been deleted or already disconnected (or never associated) with
3596  * a parent.  The chain is reassociated with the new parent and the deleted
3597  * flag will be cleared (no longer deleted).  The chain's modification state
3598  * is not altered.
3599  *
3600  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (parent) TO THE INSERTION
3601  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
3602  * FULL.  This typically means that the caller is creating the chain after
3603  * doing a hammer2_chain_lookup().
3604  *
3605  * Neither (parent) or (chain) can be errored.
3606  *
3607  * If (parent) is non-NULL then the chain is inserted under the parent.
3608  *
3609  * If (parent) is NULL then the newly duplicated chain is not inserted
3610  * anywhere, similar to if it had just been chain_alloc()'d (suitable for
3611  * passing into hammer2_chain_create() after this function returns).
3612  *
3613  * WARNING! This function calls create which means it can insert indirect
3614  *          blocks.  This can cause other unrelated chains in the parent to
3615  *          be moved to a newly inserted indirect block in addition to the
3616  *          specific chain.
3617  */
3618 void
3619 hammer2_chain_rename(hammer2_chain_t **parentp, hammer2_chain_t *chain,
3620                      hammer2_tid_t mtid, int flags)
3621 {
3622         hammer2_blockref_t *bref;
3623         hammer2_dev_t *hmp;
3624         hammer2_chain_t *parent;
3625         size_t bytes;
3626
3627         /*
3628          * WARNING!  We should never resolve DATA to device buffers
3629          *           (XXX allow it if the caller did?), and since
3630          *           we currently do not have the logical buffer cache
3631          *           buffer in-hand to fix its cached physical offset
3632          *           we also force the modify code to not COW it. XXX
3633          */
3634         hmp = chain->hmp;
3635         KKASSERT(chain->parent == NULL);
3636         KKASSERT(chain->error == 0);
3637
3638         /*
3639          * Now create a duplicate of the chain structure, associating
3640          * it with the same core, making it the same size, pointing it
3641          * to the same bref (the same media block).
3642          *
3643          * NOTE: Handle special radix == 0 case (means 0 bytes).
3644          */
3645         bref = &chain->bref;
3646         bytes = (size_t)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
3647         if (bytes)
3648                 bytes = (hammer2_off_t)1 << bytes;
3649
3650         /*
3651          * If parent is not NULL the duplicated chain will be entered under
3652          * the parent and the UPDATE bit set to tell flush to update
3653          * the blockref.
3654          *
3655          * We must setflush(parent) to ensure that it recurses through to
3656          * chain.  setflush(chain) might not work because ONFLUSH is possibly
3657          * already set in the chain (so it won't recurse up to set it in the
3658          * parent).
3659          *
3660          * Having both chains locked is extremely important for atomicy.
3661          */
3662         if (parentp && (parent = *parentp) != NULL) {
3663                 KKASSERT(hammer2_mtx_owned(&parent->lock));
3664                 KKASSERT(parent->refs > 0);
3665                 KKASSERT(parent->error == 0);
3666
3667                 hammer2_chain_create(parentp, &chain,
3668                                      chain->pmp, HAMMER2_METH_DEFAULT,
3669                                      bref->key, bref->keybits, bref->type,
3670                                      chain->bytes, mtid, 0, flags);
3671                 KKASSERT(chain->flags & HAMMER2_CHAIN_UPDATE);
3672                 hammer2_chain_setflush(*parentp);
3673         }
3674 }
3675
3676 /*
3677  * Helper function for deleting chains.
3678  *
3679  * The chain is removed from the live view (the RBTREE) as well as the parent's
3680  * blockmap.  Both chain and its parent must be locked.
3681  *
3682  * parent may not be errored.  chain can be errored.
3683  */
3684 static int
3685 _hammer2_chain_delete_helper(hammer2_chain_t *parent, hammer2_chain_t *chain,
3686                              hammer2_tid_t mtid, int flags)
3687 {
3688         hammer2_dev_t *hmp;
3689         int error = 0;
3690
3691         KKASSERT((chain->flags & (HAMMER2_CHAIN_DELETED |
3692                                   HAMMER2_CHAIN_FICTITIOUS)) == 0);
3693         KKASSERT(chain->parent == parent);
3694         hmp = chain->hmp;
3695
3696         if (chain->flags & HAMMER2_CHAIN_BMAPPED) {
3697                 /*
3698                  * Chain is blockmapped, so there must be a parent.
3699                  * Atomically remove the chain from the parent and remove
3700                  * the blockmap entry.  The parent must be set modified
3701                  * to remove the blockmap entry.
3702                  */
3703                 hammer2_blockref_t *base;
3704                 int count;
3705
3706                 KKASSERT(parent != NULL);
3707                 KKASSERT(parent->error == 0);
3708                 KKASSERT((parent->flags & HAMMER2_CHAIN_INITIAL) == 0);
3709                 error = hammer2_chain_modify(parent, mtid, 0, 0);
3710                 if (error)
3711                         goto done;
3712
3713                 /*
3714                  * Calculate blockmap pointer
3715                  */
3716                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
3717                 hammer2_spin_ex(&chain->core.spin);
3718                 hammer2_spin_ex(&parent->core.spin);
3719
3720                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3721                 atomic_add_int(&parent->core.live_count, -1);
3722                 ++parent->core.generation;
3723                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
3724                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
3725                 --parent->core.chain_count;
3726                 chain->parent = NULL;
3727
3728                 switch(parent->bref.type) {
3729                 case HAMMER2_BREF_TYPE_INODE:
3730                         /*
3731                          * Access the inode's block array.  However, there
3732                          * is no block array if the inode is flagged
3733                          * DIRECTDATA.
3734                          */
3735                         if (parent->data &&
3736                             (parent->data->ipdata.meta.op_flags &
3737                              HAMMER2_OPFLAG_DIRECTDATA) == 0) {
3738                                 base =
3739                                    &parent->data->ipdata.u.blockset.blockref[0];
3740                         } else {
3741                                 base = NULL;
3742                         }
3743                         count = HAMMER2_SET_COUNT;
3744                         break;
3745                 case HAMMER2_BREF_TYPE_INDIRECT:
3746                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3747                         if (parent->data)
3748                                 base = &parent->data->npdata[0];
3749                         else
3750                                 base = NULL;
3751                         count = parent->bytes / sizeof(hammer2_blockref_t);
3752                         break;
3753                 case HAMMER2_BREF_TYPE_VOLUME:
3754                         base = &parent->data->voldata.
3755                                         sroot_blockset.blockref[0];
3756                         count = HAMMER2_SET_COUNT;
3757                         break;
3758                 case HAMMER2_BREF_TYPE_FREEMAP:
3759                         base = &parent->data->blkset.blockref[0];
3760                         count = HAMMER2_SET_COUNT;
3761                         break;
3762                 default:
3763                         base = NULL;
3764                         count = 0;
3765                         panic("hammer2_flush_pass2: "
3766                               "unrecognized blockref type: %d",
3767                               parent->bref.type);
3768                 }
3769
3770                 /*
3771                  * delete blockmapped chain from its parent.
3772                  *
3773                  * The parent is not affected by any statistics in chain
3774                  * which are pending synchronization.  That is, there is
3775                  * nothing to undo in the parent since they have not yet
3776                  * been incorporated into the parent.
3777                  *
3778                  * The parent is affected by statistics stored in inodes.
3779                  * Those have already been synchronized, so they must be
3780                  * undone.  XXX split update possible w/delete in middle?
3781                  */
3782                 if (base) {
3783                         hammer2_base_delete(parent, base, count, chain);
3784                 }
3785                 hammer2_spin_unex(&parent->core.spin);
3786                 hammer2_spin_unex(&chain->core.spin);
3787         } else if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
3788                 /*
3789                  * Chain is not blockmapped but a parent is present.
3790                  * Atomically remove the chain from the parent.  There is
3791                  * no blockmap entry to remove.
3792                  *
3793                  * Because chain was associated with a parent but not
3794                  * synchronized, the chain's *_count_up fields contain
3795                  * inode adjustment statistics which must be undone.
3796                  */
3797                 hammer2_spin_ex(&chain->core.spin);
3798                 hammer2_spin_ex(&parent->core.spin);
3799                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3800                 atomic_add_int(&parent->core.live_count, -1);
3801                 ++parent->core.generation;
3802                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
3803                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
3804                 --parent->core.chain_count;
3805                 chain->parent = NULL;
3806                 hammer2_spin_unex(&parent->core.spin);
3807                 hammer2_spin_unex(&chain->core.spin);
3808         } else {
3809                 /*
3810                  * Chain is not blockmapped and has no parent.  This
3811                  * is a degenerate case.
3812                  */
3813                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3814         }
3815 done:
3816         return error;
3817 }
3818
3819 /*
3820  * Create an indirect block that covers one or more of the elements in the
3821  * current parent.  Either returns the existing parent with no locking or
3822  * ref changes or returns the new indirect block locked and referenced
3823  * and leaving the original parent lock/ref intact as well.
3824  *
3825  * If an error occurs, NULL is returned and *errorp is set to the H2 error.
3826  *
3827  * The returned chain depends on where the specified key falls.
3828  *
3829  * The key/keybits for the indirect mode only needs to follow three rules:
3830  *
3831  * (1) That all elements underneath it fit within its key space and
3832  *
3833  * (2) That all elements outside it are outside its key space.
3834  *
3835  * (3) When creating the new indirect block any elements in the current
3836  *     parent that fit within the new indirect block's keyspace must be
3837  *     moved into the new indirect block.
3838  *
3839  * (4) The keyspace chosen for the inserted indirect block CAN cover a wider
3840  *     keyspace the the current parent, but lookup/iteration rules will
3841  *     ensure (and must ensure) that rule (2) for all parents leading up
3842  *     to the nearest inode or the root volume header is adhered to.  This
3843  *     is accomplished by always recursing through matching keyspaces in
3844  *     the hammer2_chain_lookup() and hammer2_chain_next() API.
3845  *
3846  * The current implementation calculates the current worst-case keyspace by
3847  * iterating the current parent and then divides it into two halves, choosing
3848  * whichever half has the most elements (not necessarily the half containing
3849  * the requested key).
3850  *
3851  * We can also opt to use the half with the least number of elements.  This
3852  * causes lower-numbered keys (aka logical file offsets) to recurse through
3853  * fewer indirect blocks and higher-numbered keys to recurse through more.
3854  * This also has the risk of not moving enough elements to the new indirect
3855  * block and being forced to create several indirect blocks before the element
3856  * can be inserted.
3857  *
3858  * Must be called with an exclusively locked parent.
3859  *
3860  * NOTE: *errorp set to HAMMER_ERROR_* flags
3861  */
3862 static int hammer2_chain_indkey_freemap(hammer2_chain_t *parent,
3863                                 hammer2_key_t *keyp, int keybits,
3864                                 hammer2_blockref_t *base, int count);
3865 static int hammer2_chain_indkey_file(hammer2_chain_t *parent,
3866                                 hammer2_key_t *keyp, int keybits,
3867                                 hammer2_blockref_t *base, int count,
3868                                 int ncount);
3869 static int hammer2_chain_indkey_dir(hammer2_chain_t *parent,
3870                                 hammer2_key_t *keyp, int keybits,
3871                                 hammer2_blockref_t *base, int count,
3872                                 int ncount);
3873 static
3874 hammer2_chain_t *
3875 hammer2_chain_create_indirect(hammer2_chain_t *parent,
3876                               hammer2_key_t create_key, int create_bits,
3877                               hammer2_tid_t mtid, int for_type, int *errorp)
3878 {
3879         hammer2_dev_t *hmp;
3880         hammer2_blockref_t *base;
3881         hammer2_blockref_t *bref;
3882         hammer2_blockref_t bcopy;
3883         hammer2_chain_t *chain;
3884         hammer2_chain_t *ichain;
3885         hammer2_chain_t dummy;
3886         hammer2_key_t key = create_key;
3887         hammer2_key_t key_beg;
3888         hammer2_key_t key_end;
3889         hammer2_key_t key_next;
3890         int keybits = create_bits;
3891         int count;
3892         int ncount;
3893         int nbytes;
3894         int loops;
3895         int error;
3896         int reason;
3897         int generation;
3898         int maxloops = 300000;
3899
3900         /*
3901          * Calculate the base blockref pointer or NULL if the chain
3902          * is known to be empty.  We need to calculate the array count
3903          * for RB lookups either way.
3904          */
3905         hmp = parent->hmp;
3906         KKASSERT(hammer2_mtx_owned(&parent->lock));
3907
3908         /*
3909          * Pre-modify the parent now to avoid having to deal with error
3910          * processing if we tried to later (in the middle of our loop).
3911          */
3912         *errorp = hammer2_chain_modify(parent, mtid, 0, 0);
3913         if (*errorp) {
3914                 kprintf("hammer2_create_indirect: error %08x %s\n",
3915                         *errorp, hammer2_error_str(*errorp));
3916                 return NULL;
3917         }
3918
3919         /*hammer2_chain_modify(&parent, HAMMER2_MODIFY_OPTDATA);*/
3920         base = hammer2_chain_base_and_count(parent, &count);
3921
3922         /*
3923          * dummy used in later chain allocation (no longer used for lookups).
3924          */
3925         bzero(&dummy, sizeof(dummy));
3926
3927         /*
3928          * How big should our new indirect block be?  It has to be at least
3929          * as large as its parent for splits to work properly.
3930          *
3931          * The freemap uses a specific indirect block size.  The number of
3932          * levels are built dynamically and ultimately depend on the size
3933          * volume.  Because freemap blocks are taken from the reserved areas
3934          * of the volume our goal is efficiency (fewer levels) and not so
3935          * much to save disk space.
3936          *
3937          * The first indirect block level for a directory usually uses
3938          * HAMMER2_IND_BYTES_MIN (4KB = 32 directory entries).  Due to
3939          * the hash mechanism, this typically gives us a nominal
3940          * 32 * 4 entries with one level of indirection.
3941          *
3942          * We use HAMMER2_IND_BYTES_NOM (16KB = 128 blockrefs) for FILE
3943          * indirect blocks.  The initial 4 entries in the inode gives us
3944          * 256KB.  Up to 4 indirect blocks gives us 32MB.  Three levels
3945          * of indirection gives us 137GB, and so forth.  H2 can support
3946          * huge file sizes but they are not typical, so we try to stick
3947          * with compactness and do not use a larger indirect block size.
3948          *
3949          * We could use 64KB (PBUFSIZE), giving us 512 blockrefs, but
3950          * due to the way indirect blocks are created this usually winds
3951          * up being extremely inefficient for small files.  Even though
3952          * 16KB requires more levels of indirection for very large files,
3953          * the 16KB records can be ganged together into 64KB DIOs.
3954          */
3955         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
3956             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
3957                 nbytes = HAMMER2_FREEMAP_LEVELN_PSIZE;
3958         } else if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
3959                 if (parent->data->ipdata.meta.type ==
3960                     HAMMER2_OBJTYPE_DIRECTORY)
3961                         nbytes = HAMMER2_IND_BYTES_MIN; /* 4KB = 32 entries */
3962                 else
3963                         nbytes = HAMMER2_IND_BYTES_NOM; /* 16KB = ~8MB file */
3964
3965         } else {
3966                 nbytes = HAMMER2_IND_BYTES_NOM;
3967         }
3968         if (nbytes < count * sizeof(hammer2_blockref_t)) {
3969                 KKASSERT(for_type != HAMMER2_BREF_TYPE_FREEMAP_NODE &&
3970                          for_type != HAMMER2_BREF_TYPE_FREEMAP_LEAF);
3971                 nbytes = count * sizeof(hammer2_blockref_t);
3972         }
3973         ncount = nbytes / sizeof(hammer2_blockref_t);
3974
3975         /*
3976          * When creating an indirect block for a freemap node or leaf
3977          * the key/keybits must be fitted to static radix levels because
3978          * particular radix levels use particular reserved blocks in the
3979          * related zone.
3980          *
3981          * This routine calculates the key/radix of the indirect block
3982          * we need to create, and whether it is on the high-side or the
3983          * low-side.
3984          */
3985         switch(for_type) {
3986         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3987         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3988                 keybits = hammer2_chain_indkey_freemap(parent, &key, keybits,
3989                                                        base, count);
3990                 break;
3991         case HAMMER2_BREF_TYPE_DATA:
3992                 keybits = hammer2_chain_indkey_file(parent, &key, keybits,
3993                                                     base, count, ncount);
3994                 break;
3995         case HAMMER2_BREF_TYPE_DIRENT:
3996         case HAMMER2_BREF_TYPE_INODE:
3997                 keybits = hammer2_chain_indkey_dir(parent, &key, keybits,
3998                                                    base, count, ncount);
3999                 break;
4000         default:
4001                 panic("illegal indirect block for bref type %d", for_type);
4002                 break;
4003         }
4004
4005         /*
4006          * Normalize the key for the radix being represented, keeping the
4007          * high bits and throwing away the low bits.
4008          */
4009         key &= ~(((hammer2_key_t)1 << keybits) - 1);
4010
4011         /*
4012          * Ok, create our new indirect block
4013          */
4014         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
4015             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
4016                 dummy.bref.type = HAMMER2_BREF_TYPE_FREEMAP_NODE;
4017         } else {
4018                 dummy.bref.type = HAMMER2_BREF_TYPE_INDIRECT;
4019         }
4020         dummy.bref.key = key;
4021         dummy.bref.keybits = keybits;
4022         dummy.bref.data_off = hammer2_getradix(nbytes);
4023         dummy.bref.methods =
4024                 HAMMER2_ENC_CHECK(HAMMER2_DEC_CHECK(parent->bref.methods)) |
4025                 HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
4026
4027         ichain = hammer2_chain_alloc(hmp, parent->pmp, &dummy.bref);
4028         atomic_set_int(&ichain->flags, HAMMER2_CHAIN_INITIAL);
4029         hammer2_chain_lock(ichain, HAMMER2_RESOLVE_MAYBE);
4030         /* ichain has one ref at this point */
4031
4032         /*
4033          * We have to mark it modified to allocate its block, but use
4034          * OPTDATA to allow it to remain in the INITIAL state.  Otherwise
4035          * it won't be acted upon by the flush code.
4036          */
4037         *errorp = hammer2_chain_modify(ichain, mtid, 0, HAMMER2_MODIFY_OPTDATA);
4038         if (*errorp) {
4039                 kprintf("hammer2_alloc_indirect: error %08x %s\n",
4040                         *errorp, hammer2_error_str(*errorp));
4041                 hammer2_chain_unlock(ichain);
4042                 hammer2_chain_drop(ichain);
4043                 return NULL;
4044         }
4045
4046         /*
4047          * Iterate the original parent and move the matching brefs into
4048          * the new indirect block.
4049          *
4050          * XXX handle flushes.
4051          */
4052         key_beg = 0;
4053         key_end = HAMMER2_KEY_MAX;
4054         key_next = 0;   /* avoid gcc warnings */
4055         hammer2_spin_ex(&parent->core.spin);
4056         loops = 0;
4057         reason = 0;
4058
4059         for (;;) {
4060                 /*
4061                  * Parent may have been modified, relocating its block array.
4062                  * Reload the base pointer.
4063                  */
4064                 base = hammer2_chain_base_and_count(parent, &count);
4065
4066                 if (++loops > 100000) {
4067                     hammer2_spin_unex(&parent->core.spin);
4068                     panic("excessive loops r=%d p=%p base/count %p:%d %016jx\n",
4069                           reason, parent, base, count, key_next);
4070                 }
4071
4072                 /*
4073                  * NOTE: spinlock stays intact, returned chain (if not NULL)
4074                  *       is not referenced or locked which means that we
4075                  *       cannot safely check its flagged / deletion status
4076                  *       until we lock it.
4077                  */
4078                 chain = hammer2_combined_find(parent, base, count,
4079                                               &key_next,
4080                                               key_beg, key_end,
4081                                               &bref);
4082                 generation = parent->core.generation;
4083                 if (bref == NULL)
4084                         break;
4085                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4086
4087                 /*
4088                  * Skip keys that are not within the key/radix of the new
4089                  * indirect block.  They stay in the parent.
4090                  */
4091                 if ((~(((hammer2_key_t)1 << keybits) - 1) &
4092                     (key ^ bref->key)) != 0) {
4093                         goto next_key_spinlocked;
4094                 }
4095
4096                 /*
4097                  * Load the new indirect block by acquiring the related
4098                  * chains (potentially from media as it might not be
4099                  * in-memory).  Then move it to the new parent (ichain).
4100                  *
4101                  * chain is referenced but not locked.  We must lock the
4102                  * chain to obtain definitive state.
4103                  */
4104                 bcopy = *bref;
4105                 if (chain) {
4106                         /*
4107                          * Use chain already present in the RBTREE
4108                          */
4109                         hammer2_chain_ref(chain);
4110                         hammer2_spin_unex(&parent->core.spin);
4111                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_NEVER);
4112                 } else {
4113                         /*
4114                          * Get chain for blockref element.  _get returns NULL
4115                          * on insertion race.
4116                          */
4117                         hammer2_spin_unex(&parent->core.spin);
4118                         chain = hammer2_chain_get(parent, generation, &bcopy,
4119                                                   HAMMER2_RESOLVE_NEVER);
4120                         if (chain == NULL) {
4121                                 reason = 1;
4122                                 hammer2_spin_ex(&parent->core.spin);
4123                                 continue;
4124                         }
4125                 }
4126
4127                 /*
4128                  * This is always live so if the chain has been deleted
4129                  * we raced someone and we have to retry.
4130                  *
4131                  * NOTE: Lookups can race delete-duplicate because
4132                  *       delete-duplicate does not lock the parent's core
4133                  *       (they just use the spinlock on the core).
4134                  *
4135                  *       (note reversed logic for this one)
4136                  */
4137                 if (bcmp(&bcopy, &chain->bref, sizeof(bcopy)) ||
4138                     chain->parent != parent ||
4139                     (chain->flags & HAMMER2_CHAIN_DELETED)) {
4140                         hammer2_chain_unlock(chain);
4141                         hammer2_chain_drop(chain);
4142                         if (hammer2_debug & 0x0040) {
4143                                 kprintf("LOST PARENT RETRY "
4144                                 "RETRY (%p,%p)->%p %08x\n",
4145                                 parent, chain->parent, chain, chain->flags);
4146                         }
4147                         hammer2_spin_ex(&parent->core.spin);
4148                         continue;
4149                 }
4150
4151                 /*
4152                  * Shift the chain to the indirect block.
4153                  *
4154                  * WARNING! No reason for us to load chain data, pass NOSTATS
4155                  *          to prevent delete/insert from trying to access
4156                  *          inode stats (and thus asserting if there is no
4157                  *          chain->data loaded).
4158                  *
4159                  * WARNING! The (parent, chain) deletion may modify the parent
4160                  *          and invalidate the base pointer.
4161                  *
4162                  * WARNING! Parent must already be marked modified, so we
4163                  *          can assume that chain_delete always suceeds.
4164                  *
4165                  * WARNING! hammer2_chain_repchange() does not have to be
4166                  *          called (and doesn't work anyway because we are
4167                  *          only doing a partial shift).  A recursion that is
4168                  *          in-progress can continue at the current parent
4169                  *          and will be able to properly find its next key.
4170                  */
4171                 error = hammer2_chain_delete(parent, chain, mtid, 0);
4172                 KKASSERT(error == 0);
4173                 hammer2_chain_rename(&ichain, chain, mtid, 0);
4174                 hammer2_chain_unlock(chain);
4175                 hammer2_chain_drop(chain);
4176                 KKASSERT(parent->refs > 0);
4177                 chain = NULL;
4178                 base = NULL;    /* safety */
4179                 hammer2_spin_ex(&parent->core.spin);
4180 next_key_spinlocked:
4181                 if (--maxloops == 0)
4182                         panic("hammer2_chain_create_indirect: maxloops");
4183                 reason = 4;
4184                 if (key_next == 0 || key_next > key_end)
4185                         break;
4186                 key_beg = key_next;
4187                 /* loop */
4188         }
4189         hammer2_spin_unex(&parent->core.spin);
4190
4191         /*
4192          * Insert the new indirect block into the parent now that we've
4193          * cleared out some entries in the parent.  We calculated a good
4194          * insertion index in the loop above (ichain->index).
4195          *
4196          * We don't have to set UPDATE here because we mark ichain
4197          * modified down below (so the normal modified -> flush -> set-moved
4198          * sequence applies).
4199          *
4200          * The insertion shouldn't race as this is a completely new block
4201          * and the parent is locked.
4202          */
4203         base = NULL;    /* safety, parent modify may change address */
4204         KKASSERT((ichain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
4205         KKASSERT(parent->core.live_count < count);
4206         hammer2_chain_insert(parent, ichain,
4207                              HAMMER2_CHAIN_INSERT_SPIN |
4208                              HAMMER2_CHAIN_INSERT_LIVE,
4209                              0);
4210
4211         /*
4212          * Make sure flushes propogate after our manual insertion.
4213          */
4214         hammer2_chain_setflush(ichain);
4215         hammer2_chain_setflush(parent);
4216
4217         /*
4218          * Figure out what to return.
4219          */
4220         if (~(((hammer2_key_t)1 << keybits) - 1) &
4221                    (create_key ^ key)) {
4222                 /*
4223                  * Key being created is outside the key range,
4224                  * return the original parent.
4225                  */
4226                 hammer2_chain_unlock(ichain);
4227                 hammer2_chain_drop(ichain);
4228         } else {
4229                 /*
4230                  * Otherwise its in the range, return the new parent.
4231                  * (leave both the new and old parent locked).
4232                  */
4233                 parent = ichain;
4234         }
4235
4236         return(parent);
4237 }
4238
4239 /*
4240  * Do maintenance on an indirect chain.  Both parent and chain are locked.
4241  *
4242  * Returns non-zero if (chain) is deleted, either due to being empty or
4243  * because its children were safely moved into the parent.
4244  */
4245 int
4246 hammer2_chain_indirect_maintenance(hammer2_chain_t *parent,
4247                                    hammer2_chain_t *chain)
4248 {
4249         hammer2_blockref_t *chain_base;
4250         hammer2_blockref_t *base;
4251         hammer2_blockref_t *bref;
4252         hammer2_blockref_t bcopy;
4253         hammer2_key_t key_next;
4254         hammer2_key_t key_beg;
4255         hammer2_key_t key_end;
4256         hammer2_chain_t *sub;
4257         int chain_count;
4258         int count;
4259         int error;
4260         int generation;
4261
4262         /*
4263          * Make sure we have an accurate live_count
4264          */
4265         if ((chain->flags & (HAMMER2_CHAIN_INITIAL |
4266                              HAMMER2_CHAIN_COUNTEDBREFS)) == 0) {
4267                 base = &chain->data->npdata[0];
4268                 count = chain->bytes / sizeof(hammer2_blockref_t);
4269                 hammer2_chain_countbrefs(chain, base, count);
4270         }
4271
4272         /*
4273          * If the indirect block is empty we can delete it.
4274          * (ignore deletion error)
4275          */
4276         if (chain->core.live_count == 0 && RB_EMPTY(&chain->core.rbtree)) {
4277                 hammer2_chain_delete(parent, chain,
4278                                      chain->bref.modify_tid,
4279                                      HAMMER2_DELETE_PERMANENT);
4280                 hammer2_chain_repchange(parent, chain);
4281                 return 1;
4282         }
4283
4284         base = hammer2_chain_base_and_count(parent, &count);
4285
4286         if ((parent->flags & (HAMMER2_CHAIN_INITIAL |
4287                              HAMMER2_CHAIN_COUNTEDBREFS)) == 0) {
4288                 hammer2_chain_countbrefs(parent, base, count);
4289         }
4290
4291         /*
4292          * Determine if we can collapse chain into parent, calculate
4293          * hysteresis for chain emptiness.
4294          */
4295         if (parent->core.live_count + chain->core.live_count - 1 > count)
4296                 return 0;
4297         chain_count = chain->bytes / sizeof(hammer2_blockref_t);
4298         if (chain->core.live_count > chain_count * 3 / 4)
4299                 return 0;
4300
4301         /*
4302          * Ok, theoretically we can collapse chain's contents into
4303          * parent.  chain is locked, but any in-memory children of chain
4304          * are not.  For this to work, we must be able to dispose of any
4305          * in-memory children of chain.
4306          *
4307          * For now require that there are no in-memory children of chain.
4308          *
4309          * WARNING! Both chain and parent must remain locked across this
4310          *          entire operation.
4311          */
4312
4313         /*
4314          * Parent must be marked modified.  Don't try to collapse it if we
4315          * can't mark it modified.  Once modified, destroy chain to make room
4316          * and to get rid of what will be a conflicting key (this is included
4317          * in the calculation above).  Finally, move the children of chain
4318          * into chain's parent.
4319          *
4320          * This order creates an accounting problem for bref.embed.stats
4321          * because we destroy chain before we remove its children.  Any
4322          * elements whos blockref is already synchronized will be counted
4323          * twice.  To deal with the problem we clean out chain's stats prior
4324          * to deleting it.
4325          */
4326         error = hammer2_chain_modify(parent, 0, 0, 0);
4327         if (error) {
4328                 krateprintf(&krate_h2me, "hammer2: indirect_maint: %s\n",
4329                             hammer2_error_str(error));
4330                 return 0;
4331         }
4332         error = hammer2_chain_modify(chain, chain->bref.modify_tid, 0, 0);
4333         if (error) {
4334                 krateprintf(&krate_h2me, "hammer2: indirect_maint: %s\n",
4335                             hammer2_error_str(error));
4336                 return 0;
4337         }
4338
4339         chain->bref.embed.stats.inode_count = 0;
4340         chain->bref.embed.stats.data_count = 0;
4341         error = hammer2_chain_delete(parent, chain,
4342                                      chain->bref.modify_tid,
4343                                      HAMMER2_DELETE_PERMANENT);
4344         KKASSERT(error == 0);
4345
4346         /*
4347          * The combined_find call requires core.spin to be held.  One would
4348          * think there wouldn't be any conflicts since we hold chain
4349          * exclusively locked, but the caching mechanism for 0-ref children
4350          * does not require a chain lock.
4351          */
4352         hammer2_spin_ex(&chain->core.spin);
4353
4354         key_next = 0;
4355         key_beg = 0;
4356         key_end = HAMMER2_KEY_MAX;
4357         for (;;) {
4358                 chain_base = &chain->data->npdata[0];
4359                 chain_count = chain->bytes / sizeof(hammer2_blockref_t);
4360                 sub = hammer2_combined_find(chain, chain_base, chain_count,
4361                                             &key_next,
4362                                             key_beg, key_end,
4363                                             &bref);
4364                 generation = chain->core.generation;
4365                 if (bref == NULL)
4366                         break;
4367                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4368
4369                 bcopy = *bref;
4370                 if (sub) {
4371                         hammer2_chain_ref(sub);
4372                         hammer2_spin_unex(&chain->core.spin);
4373                         hammer2_chain_lock(sub, HAMMER2_RESOLVE_NEVER);
4374                 } else {
4375                         hammer2_spin_unex(&chain->core.spin);
4376                         sub = hammer2_chain_get(chain, generation, &bcopy,
4377                                                 HAMMER2_RESOLVE_NEVER);
4378                         if (sub == NULL) {
4379                                 hammer2_spin_ex(&chain->core.spin);
4380                                 continue;
4381                         }
4382                 }
4383                 if (bcmp(&bcopy, &sub->bref, sizeof(bcopy)) ||
4384                     sub->parent != chain ||
4385                     (sub->flags & HAMMER2_CHAIN_DELETED)) {
4386                         hammer2_chain_unlock(sub);
4387                         hammer2_chain_drop(sub);
4388                         hammer2_spin_ex(&chain->core.spin);
4389                         sub = NULL;     /* safety */
4390                         continue;
4391                 }
4392                 error = hammer2_chain_delete(chain, sub,
4393                                              sub->bref.modify_tid, 0);
4394                 KKASSERT(error == 0);
4395                 hammer2_chain_rename(&parent, sub,
4396                                      sub->bref.modify_tid,
4397                                      HAMMER2_INSERT_SAMEPARENT);
4398                 hammer2_chain_unlock(sub);
4399                 hammer2_chain_drop(sub);
4400                 hammer2_spin_ex(&chain->core.spin);
4401
4402                 if (key_next == 0)
4403                         break;
4404                 key_beg = key_next;
4405         }
4406         hammer2_spin_unex(&chain->core.spin);
4407
4408         hammer2_chain_repchange(parent, chain);
4409
4410         return 1;
4411 }
4412
4413 /*
4414  * Freemap indirect blocks
4415  *
4416  * Calculate the keybits and highside/lowside of the freemap node the
4417  * caller is creating.
4418  *
4419  * This routine will specify the next higher-level freemap key/radix
4420  * representing the lowest-ordered set.  By doing so, eventually all
4421  * low-ordered sets will be moved one level down.
4422  *
4423  * We have to be careful here because the freemap reserves a limited
4424  * number of blocks for a limited number of levels.  So we can't just
4425  * push indiscriminately.
4426  */
4427 int
4428 hammer2_chain_indkey_freemap(hammer2_chain_t *parent, hammer2_key_t *keyp,
4429                              int keybits, hammer2_blockref_t *base, int count)
4430 {
4431         hammer2_chain_t *chain;
4432         hammer2_blockref_t *bref;
4433         hammer2_key_t key;
4434         hammer2_key_t key_beg;
4435         hammer2_key_t key_end;
4436         hammer2_key_t key_next;
4437         int locount;
4438         int hicount;
4439         int maxloops = 300000;
4440
4441         key = *keyp;
4442         locount = 0;
4443         hicount = 0;
4444         keybits = 64;
4445
4446         /*
4447          * Calculate the range of keys in the array being careful to skip
4448          * slots which are overridden with a deletion.
4449          */
4450         key_beg = 0;
4451         key_end = HAMMER2_KEY_MAX;
4452         hammer2_spin_ex(&parent->core.spin);
4453
4454         for (;;) {
4455                 if (--maxloops == 0) {
4456                         panic("indkey_freemap shit %p %p:%d\n",
4457                               parent, base, count);
4458                 }
4459                 chain = hammer2_combined_find(parent, base, count,
4460                                               &key_next,
4461                                               key_beg, key_end,
4462                                               &bref);
4463
4464                 /*
4465                  * Exhausted search
4466                  */
4467                 if (bref == NULL)
4468                         break;
4469
4470                 /*
4471                  * Skip deleted chains.
4472                  */
4473                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4474                         if (key_next == 0 || key_next > key_end)
4475                                 break;
4476                         key_beg = key_next;
4477                         continue;
4478                 }
4479
4480                 /*
4481                  * Use the full live (not deleted) element for the scan
4482                  * iteration.  HAMMER2 does not allow partial replacements.
4483                  *
4484                  * XXX should be built into hammer2_combined_find().
4485                  */
4486                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4487
4488                 if (keybits > bref->keybits) {
4489                         key = bref->key;
4490                         keybits = bref->keybits;
4491                 } else if (keybits == bref->keybits && bref->key < key) {
4492                         key = bref->key;
4493                 }
4494                 if (key_next == 0)
4495                         break;
4496                 key_beg = key_next;
4497         }
4498         hammer2_spin_unex(&parent->core.spin);
4499
4500         /*
4501          * Return the keybits for a higher-level FREEMAP_NODE covering
4502          * this node.
4503          */
4504         switch(keybits) {
4505         case HAMMER2_FREEMAP_LEVEL0_RADIX:
4506                 keybits = HAMMER2_FREEMAP_LEVEL1_RADIX;
4507                 break;
4508         case HAMMER2_FREEMAP_LEVEL1_RADIX:
4509                 keybits = HAMMER2_FREEMAP_LEVEL2_RADIX;
4510                 break;
4511         case HAMMER2_FREEMAP_LEVEL2_RADIX:
4512                 keybits = HAMMER2_FREEMAP_LEVEL3_RADIX;
4513                 break;
4514         case HAMMER2_FREEMAP_LEVEL3_RADIX:
4515                 keybits = HAMMER2_FREEMAP_LEVEL4_RADIX;
4516                 break;
4517         case HAMMER2_FREEMAP_LEVEL4_RADIX:
4518                 keybits = HAMMER2_FREEMAP_LEVEL5_RADIX;
4519                 break;
4520         case HAMMER2_FREEMAP_LEVEL5_RADIX:
4521                 panic("hammer2_chain_indkey_freemap: level too high");
4522                 break;
4523         default:
4524                 panic("hammer2_chain_indkey_freemap: bad radix");
4525                 break;
4526         }
4527         *keyp = key;
4528
4529         return (keybits);
4530 }
4531
4532 /*
4533  * File indirect blocks
4534  *
4535  * Calculate the key/keybits for the indirect block to create by scanning
4536  * existing keys.  The key being created is also passed in *keyp and can be
4537  * inside or outside the indirect block.  Regardless, the indirect block
4538  * must hold at least two keys in order to guarantee sufficient space.
4539  *
4540  * We use a modified version of the freemap's fixed radix tree, but taylored
4541  * for file data.  Basically we configure an indirect block encompassing the
4542  * smallest key.
4543  */
4544 static int
4545 hammer2_chain_indkey_file(hammer2_chain_t *parent, hammer2_key_t *keyp,
4546                             int keybits, hammer2_blockref_t *base, int count,
4547                             int ncount)
4548 {
4549         hammer2_chain_t *chain;
4550         hammer2_blockref_t *bref;
4551         hammer2_key_t key;
4552         hammer2_key_t key_beg;
4553         hammer2_key_t key_end;
4554         hammer2_key_t key_next;
4555         int nradix;
4556         int locount;
4557         int hicount;
4558         int maxloops = 300000;
4559
4560         key = *keyp;
4561         locount = 0;
4562         hicount = 0;
4563         keybits = 64;
4564
4565         /*
4566          * Calculate the range of keys in the array being careful to skip
4567          * slots which are overridden with a deletion.
4568          *
4569          * Locate the smallest key.
4570          */
4571         key_beg = 0;
4572         key_end = HAMMER2_KEY_MAX;
4573         hammer2_spin_ex(&parent->core.spin);
4574
4575         for (;;) {
4576                 if (--maxloops == 0) {
4577                         panic("indkey_freemap shit %p %p:%d\n",
4578                               parent, base, count);
4579                 }
4580                 chain = hammer2_combined_find(parent, base, count,
4581                                               &key_next,
4582                                               key_beg, key_end,
4583                                               &bref);
4584
4585                 /*
4586                  * Exhausted search
4587                  */
4588                 if (bref == NULL)
4589                         break;
4590
4591                 /*
4592                  * Skip deleted chains.
4593                  */
4594                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4595                         if (key_next == 0 || key_next > key_end)
4596                                 break;
4597                         key_beg = key_next;
4598                         continue;
4599                 }
4600
4601                 /*
4602                  * Use the full live (not deleted) element for the scan
4603                  * iteration.  HAMMER2 does not allow partial replacements.
4604                  *
4605                  * XXX should be built into hammer2_combined_find().
4606                  */
4607                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4608
4609                 if (keybits > bref->keybits) {
4610                         key = bref->key;
4611                         keybits = bref->keybits;
4612                 } else if (keybits == bref->keybits && bref->key < key) {
4613                         key = bref->key;
4614                 }
4615                 if (key_next == 0)
4616                         break;
4617                 key_beg = key_next;
4618         }
4619         hammer2_spin_unex(&parent->core.spin);
4620
4621         /*
4622          * Calculate the static keybits for a higher-level indirect block
4623          * that contains the key.
4624          */
4625         *keyp = key;
4626
4627         switch(ncount) {
4628         case HAMMER2_IND_BYTES_MIN / sizeof(hammer2_blockref_t):
4629                 nradix = HAMMER2_IND_RADIX_MIN - HAMMER2_BLOCKREF_RADIX;
4630                 break;
4631         case HAMMER2_IND_BYTES_NOM / sizeof(hammer2_blockref_t):
4632                 nradix = HAMMER2_IND_RADIX_NOM - HAMMER2_BLOCKREF_RADIX;
4633                 break;
4634         case HAMMER2_IND_BYTES_MAX / sizeof(hammer2_blockref_t):
4635                 nradix = HAMMER2_IND_RADIX_MAX - HAMMER2_BLOCKREF_RADIX;
4636                 break;
4637         default:
4638                 panic("bad ncount %d\n", ncount);
4639                 nradix = 0;
4640                 break;
4641         }
4642
4643         /*
4644          * The largest radix that can be returned for an indirect block is
4645          * 63 bits.  (The largest practical indirect block radix is actually
4646          * 62 bits because the top-level inode or volume root contains four
4647          * entries, but allow 63 to be returned).
4648          */
4649         if (nradix >= 64)
4650                 nradix = 63;
4651
4652         return keybits + nradix;
4653 }
4654
4655 #if 1
4656
4657 /*
4658  * Directory indirect blocks.
4659  *
4660  * Covers both the inode index (directory of inodes), and directory contents
4661  * (filenames hardlinked to inodes).
4662  *
4663  * Because directory keys are hashed we generally try to cut the space in
4664  * half.  We accomodate the inode index (which tends to have linearly
4665  * increasing inode numbers) by ensuring that the keyspace is at least large
4666  * enough to fill up the indirect block being created.
4667  */
4668 static int
4669 hammer2_chain_indkey_dir(hammer2_chain_t *parent, hammer2_key_t *keyp,
4670                          int keybits, hammer2_blockref_t *base, int count,
4671                          int ncount)
4672 {
4673         hammer2_blockref_t *bref;
4674         hammer2_chain_t *chain;
4675         hammer2_key_t key_beg;
4676         hammer2_key_t key_end;
4677         hammer2_key_t key_next;
4678         hammer2_key_t key;
4679         int nkeybits;
4680         int locount;
4681         int hicount;
4682         int maxloops = 300000;
4683
4684         /*
4685          * NOTE: We can't take a shortcut here anymore for inodes because
4686          *       the root directory can contain a mix of inodes and directory
4687          *       entries (we used to just return 63 if parent->bref.type was
4688          *       HAMMER2_BREF_TYPE_INODE.
4689          */
4690         key = *keyp;
4691         locount = 0;
4692         hicount = 0;
4693
4694         /*
4695          * Calculate the range of keys in the array being careful to skip
4696          * slots which are overridden with a deletion.
4697          */
4698         key_beg = 0;
4699         key_end = HAMMER2_KEY_MAX;
4700         hammer2_spin_ex(&parent->core.spin);
4701
4702         for (;;) {
4703                 if (--maxloops == 0) {
4704                         panic("indkey_freemap shit %p %p:%d\n",
4705                               parent, base, count);
4706                 }
4707                 chain = hammer2_combined_find(parent, base, count,
4708                                               &key_next,
4709                                               key_beg, key_end,
4710                                               &bref);
4711
4712                 /*
4713                  * Exhausted search
4714                  */
4715                 if (bref == NULL)
4716                         break;
4717
4718                 /*
4719                  * Deleted object
4720                  */
4721                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4722                         if (key_next == 0 || key_next > key_end)
4723                                 break;
4724                         key_beg = key_next;
4725                         continue;
4726                 }
4727
4728                 /*
4729                  * Use the full live (not deleted) element for the scan
4730                  * iteration.  HAMMER2 does not allow partial replacements.
4731                  *
4732                  * XXX should be built into hammer2_combined_find().
4733                  */
4734                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4735
4736                 /*
4737                  * Expand our calculated key range (key, keybits) to fit
4738                  * the scanned key.  nkeybits represents the full range
4739                  * that we will later cut in half (two halves @ nkeybits - 1).
4740                  */
4741                 nkeybits = keybits;
4742                 if (nkeybits < bref->keybits) {
4743                         if (bref->keybits > 64) {
4744                                 kprintf("bad bref chain %p bref %p\n",
4745                                         chain, bref);
4746                                 Debugger("fubar");
4747                         }
4748                         nkeybits = bref->keybits;
4749                 }
4750                 while (nkeybits < 64 &&
4751                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
4752                         (key ^ bref->key)) != 0) {
4753                         ++nkeybits;
4754                 }
4755
4756                 /*
4757                  * If the new key range is larger we have to determine
4758                  * which side of the new key range the existing keys fall
4759                  * under by checking the high bit, then collapsing the
4760                  * locount into the hicount or vise-versa.
4761                  */
4762                 if (keybits != nkeybits) {
4763                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
4764                                 hicount += locount;
4765                                 locount = 0;
4766                         } else {
4767                                 locount += hicount;
4768                                 hicount = 0;
4769                         }
4770                         keybits = nkeybits;
4771                 }
4772
4773                 /*
4774                  * The newly scanned key will be in the lower half or the
4775                  * upper half of the (new) key range.
4776                  */
4777                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
4778                         ++hicount;
4779                 else
4780                         ++locount;
4781
4782                 if (key_next == 0)
4783                         break;
4784                 key_beg = key_next;
4785         }
4786         hammer2_spin_unex(&parent->core.spin);
4787         bref = NULL;    /* now invalid (safety) */
4788
4789         /*
4790          * Adjust keybits to represent half of the full range calculated
4791          * above (radix 63 max) for our new indirect block.
4792          */
4793         --keybits;
4794
4795         /*
4796          * Expand keybits to hold at least ncount elements.  ncount will be
4797          * a power of 2.  This is to try to completely fill leaf nodes (at
4798          * least for keys which are not hashes).
4799          *
4800          * We aren't counting 'in' or 'out', we are counting 'high side'
4801          * and 'low side' based on the bit at (1LL << keybits).  We want
4802          * everything to be inside in these cases so shift it all to
4803          * the low or high side depending on the new high bit.
4804          */
4805         while (((hammer2_key_t)1 << keybits) < ncount) {
4806                 ++keybits;
4807                 if (key & ((hammer2_key_t)1 << keybits)) {
4808                         hicount += locount;
4809                         locount = 0;
4810                 } else {
4811                         locount += hicount;
4812                         hicount = 0;
4813                 }
4814         }
4815
4816         if (hicount > locount)
4817                 key |= (hammer2_key_t)1 << keybits;
4818         else
4819                 key &= ~(hammer2_key_t)1 << keybits;
4820
4821         *keyp = key;
4822
4823         return (keybits);
4824 }
4825
4826 #else
4827
4828 /*
4829  * Directory indirect blocks.
4830  *
4831  * Covers both the inode index (directory of inodes), and directory contents
4832  * (filenames hardlinked to inodes).
4833  *
4834  * Because directory keys are hashed we generally try to cut the space in
4835  * half.  We accomodate the inode index (which tends to have linearly
4836  * increasing inode numbers) by ensuring that the keyspace is at least large
4837  * enough to fill up the indirect block being created.
4838  */
4839 static int
4840 hammer2_chain_indkey_dir(hammer2_chain_t *parent, hammer2_key_t *keyp,
4841                          int keybits, hammer2_blockref_t *base, int count,
4842                          int ncount)
4843 {
4844         hammer2_blockref_t *bref;
4845         hammer2_chain_t *chain;
4846         hammer2_key_t key_beg;
4847         hammer2_key_t key_end;
4848         hammer2_key_t key_next;
4849         hammer2_key_t key;
4850         int nkeybits;
4851         int locount;
4852         int hicount;
4853         int maxloops = 300000;
4854
4855         /*
4856          * Shortcut if the parent is the inode.  In this situation the
4857          * parent has 4+1 directory entries and we are creating an indirect
4858          * block capable of holding many more.
4859          */
4860         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
4861                 return 63;
4862         }
4863
4864         key = *keyp;
4865         locount = 0;
4866         hicount = 0;
4867
4868         /*
4869          * Calculate the range of keys in the array being careful to skip
4870          * slots which are overridden with a deletion.
4871          */
4872         key_beg = 0;
4873         key_end = HAMMER2_KEY_MAX;
4874         hammer2_spin_ex(&parent->core.spin);
4875
4876         for (;;) {
4877                 if (--maxloops == 0) {
4878                         panic("indkey_freemap shit %p %p:%d\n",
4879                               parent, base, count);
4880                 }
4881                 chain = hammer2_combined_find(parent, base, count,
4882                                               &key_next,
4883                                               key_beg, key_end,
4884                                               &bref);
4885
4886                 /*
4887                  * Exhausted search
4888                  */
4889                 if (bref == NULL)
4890                         break;
4891
4892                 /*
4893                  * Deleted object
4894                  */
4895                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4896                         if (key_next == 0 || key_next > key_end)
4897                                 break;
4898                         key_beg = key_next;
4899                         continue;
4900                 }
4901
4902                 /*
4903                  * Use the full live (not deleted) element for the scan
4904                  * iteration.  HAMMER2 does not allow partial replacements.
4905                  *
4906                  * XXX should be built into hammer2_combined_find().
4907                  */
4908                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4909
4910                 /*
4911                  * Expand our calculated key range (key, keybits) to fit
4912                  * the scanned key.  nkeybits represents the full range
4913                  * that we will later cut in half (two halves @ nkeybits - 1).
4914                  */
4915                 nkeybits = keybits;
4916                 if (nkeybits < bref->keybits) {
4917                         if (bref->keybits > 64) {
4918                                 kprintf("bad bref chain %p bref %p\n",
4919                                         chain, bref);
4920                                 Debugger("fubar");
4921                         }
4922                         nkeybits = bref->keybits;
4923                 }
4924                 while (nkeybits < 64 &&
4925                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
4926                         (key ^ bref->key)) != 0) {
4927                         ++nkeybits;
4928                 }
4929
4930                 /*
4931                  * If the new key range is larger we have to determine
4932                  * which side of the new key range the existing keys fall
4933                  * under by checking the high bit, then collapsing the
4934                  * locount into the hicount or vise-versa.
4935                  */
4936                 if (keybits != nkeybits) {
4937                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
4938                                 hicount += locount;
4939                                 locount = 0;
4940                         } else {
4941                                 locount += hicount;
4942                                 hicount = 0;
4943                         }
4944                         keybits = nkeybits;
4945                 }
4946
4947                 /*
4948                  * The newly scanned key will be in the lower half or the
4949                  * upper half of the (new) key range.
4950                  */
4951                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
4952                         ++hicount;
4953                 else
4954                         ++locount;
4955
4956                 if (key_next == 0)
4957                         break;
4958                 key_beg = key_next;
4959         }
4960         hammer2_spin_unex(&parent->core.spin);
4961         bref = NULL;    /* now invalid (safety) */
4962
4963         /*
4964          * Adjust keybits to represent half of the full range calculated
4965          * above (radix 63 max) for our new indirect block.
4966          */
4967         --keybits;
4968
4969         /*
4970          * Expand keybits to hold at least ncount elements.  ncount will be
4971          * a power of 2.  This is to try to completely fill leaf nodes (at
4972          * least for keys which are not hashes).
4973          *
4974          * We aren't counting 'in' or 'out', we are counting 'high side'
4975          * and 'low side' based on the bit at (1LL << keybits).  We want
4976          * everything to be inside in these cases so shift it all to
4977          * the low or high side depending on the new high bit.
4978          */
4979         while (((hammer2_key_t)1 << keybits) < ncount) {
4980                 ++keybits;
4981                 if (key & ((hammer2_key_t)1 << keybits)) {
4982                         hicount += locount;
4983                         locount = 0;
4984                 } else {
4985                         locount += hicount;
4986                         hicount = 0;
4987                 }
4988         }
4989
4990         if (hicount > locount)
4991                 key |= (hammer2_key_t)1 << keybits;
4992         else
4993                 key &= ~(hammer2_key_t)1 << keybits;
4994
4995         *keyp = key;
4996
4997         return (keybits);
4998 }
4999
5000 #endif
5001
5002 /*
5003  * Sets CHAIN_DELETED and remove the chain's blockref from the parent if
5004  * it exists.
5005  *
5006  * Both parent and chain must be locked exclusively.
5007  *
5008  * This function will modify the parent if the blockref requires removal
5009  * from the parent's block table.
5010  *
5011  * This function is NOT recursive.  Any entity already pushed into the
5012  * chain (such as an inode) may still need visibility into its contents,
5013  * as well as the ability to read and modify the contents.  For example,
5014  * for an unlinked file which is still open.
5015  *
5016  * Also note that the flusher is responsible for cleaning up empty
5017  * indirect blocks.
5018  */
5019 int
5020 hammer2_chain_delete(hammer2_chain_t *parent, hammer2_chain_t *chain,
5021                      hammer2_tid_t mtid, int flags)
5022 {
5023         int error = 0;
5024
5025         KKASSERT(hammer2_mtx_owned(&chain->lock));
5026
5027         /*
5028          * Nothing to do if already marked.
5029          *
5030          * We need the spinlock on the core whos RBTREE contains chain
5031          * to protect against races.
5032          */
5033         if ((chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
5034                 KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0 &&
5035                          chain->parent == parent);
5036                 error = _hammer2_chain_delete_helper(parent, chain,
5037                                                      mtid, flags);
5038         }
5039
5040         /*
5041          * Permanent deletions mark the chain as destroyed.
5042          *
5043          * NOTE: We do not setflush the chain unless the deletion is
5044          *       permanent, since the deletion of a chain does not actually
5045          *       require it to be flushed.
5046          */
5047         if (error == 0) {
5048                 if (flags & HAMMER2_DELETE_PERMANENT) {
5049                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
5050                         hammer2_chain_setflush(chain);
5051                 }
5052         }
5053
5054         return error;
5055 }
5056
5057 /*
5058  * Returns the index of the nearest element in the blockref array >= elm.
5059  * Returns (count) if no element could be found.
5060  *
5061  * Sets *key_nextp to the next key for loop purposes but does not modify
5062  * it if the next key would be higher than the current value of *key_nextp.
5063  * Note that *key_nexp can overflow to 0, which should be tested by the
5064  * caller.
5065  *
5066  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
5067  *           held through the operation.
5068  */
5069 static int
5070 hammer2_base_find(hammer2_chain_t *parent,
5071                   hammer2_blockref_t *base, int count,
5072                   hammer2_key_t *key_nextp,
5073                   hammer2_key_t key_beg, hammer2_key_t key_end)
5074 {
5075         hammer2_blockref_t *scan;
5076         hammer2_key_t scan_end;
5077         int i;
5078         int limit;
5079
5080         /*
5081          * Require the live chain's already have their core's counted
5082          * so we can optimize operations.
5083          */
5084         KKASSERT(parent->flags & HAMMER2_CHAIN_COUNTEDBREFS);
5085
5086         /*
5087          * Degenerate case
5088          */
5089         if (count == 0 || base == NULL)
5090                 return(count);
5091
5092         /*
5093          * Sequential optimization using parent->cache_index.  This is
5094          * the most likely scenario.
5095          *
5096          * We can avoid trailing empty entries on live chains, otherwise
5097          * we might have to check the whole block array.
5098          */
5099         i = parent->cache_index;        /* SMP RACE OK */
5100         cpu_ccfence();
5101         limit = parent->core.live_zero;
5102         if (i >= limit)
5103                 i = limit - 1;
5104         if (i < 0)
5105                 i = 0;
5106         KKASSERT(i < count);
5107
5108         /*
5109          * Search backwards
5110          */
5111         scan = &base[i];
5112         while (i > 0 && (scan->type == 0 || scan->key > key_beg)) {
5113                 --scan;
5114                 --i;
5115         }
5116         parent->cache_index = i;
5117
5118         /*
5119          * Search forwards, stop when we find a scan element which
5120          * encloses the key or until we know that there are no further
5121          * elements.
5122          */
5123         while (i < count) {
5124                 if (scan->type != 0) {
5125                         scan_end = scan->key +
5126                                    ((hammer2_key_t)1 << scan->keybits) - 1;
5127                         if (scan->key > key_beg || scan_end >= key_beg)
5128                                 break;
5129                 }
5130                 if (i >= limit)
5131                         return (count);
5132                 ++scan;
5133                 ++i;
5134         }
5135         if (i != count) {
5136                 parent->cache_index = i;
5137                 if (i >= limit) {
5138                         i = count;
5139                 } else {
5140                         scan_end = scan->key +
5141                                    ((hammer2_key_t)1 << scan->keybits);
5142                         if (scan_end && (*key_nextp > scan_end ||
5143                                          *key_nextp == 0)) {
5144                                 *key_nextp = scan_end;
5145                         }
5146                 }
5147         }
5148         return (i);
5149 }
5150
5151 /*
5152  * Do a combined search and return the next match either from the blockref
5153  * array or from the in-memory chain.  Sets *bresp to the returned bref in
5154  * both cases, or sets it to NULL if the search exhausted.  Only returns
5155  * a non-NULL chain if the search matched from the in-memory chain.
5156  *
5157  * When no in-memory chain has been found and a non-NULL bref is returned
5158  * in *bresp.
5159  *
5160  *
5161  * The returned chain is not locked or referenced.  Use the returned bref
5162  * to determine if the search exhausted or not.  Iterate if the base find
5163  * is chosen but matches a deleted chain.
5164  *
5165  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
5166  *           held through the operation.
5167  */
5168 hammer2_chain_t *
5169 hammer2_combined_find(hammer2_chain_t *parent,
5170                       hammer2_blockref_t *base, int count,
5171                       hammer2_key_t *key_nextp,
5172                       hammer2_key_t key_beg, hammer2_key_t key_end,
5173                       hammer2_blockref_t **bresp)
5174 {
5175         hammer2_blockref_t *bref;
5176         hammer2_chain_t *chain;
5177         int i;
5178
5179         /*
5180          * Lookup in block array and in rbtree.
5181          */
5182         *key_nextp = key_end + 1;
5183         i = hammer2_base_find(parent, base, count, key_nextp,
5184                               key_beg, key_end);
5185         chain = hammer2_chain_find(parent, key_nextp, key_beg, key_end);
5186
5187         /*
5188          * Neither matched
5189          */
5190         if (i == count && chain == NULL) {
5191                 *bresp = NULL;
5192                 return(NULL);
5193         }
5194
5195         /*
5196          * Only chain matched.
5197          */
5198         if (i == count) {
5199                 bref = &chain->bref;
5200                 goto found;
5201         }
5202
5203         /*
5204          * Only blockref matched.
5205          */
5206         if (chain == NULL) {
5207                 bref = &base[i];
5208                 goto found;
5209         }
5210
5211         /*
5212          * Both in-memory and blockref matched, select the nearer element.
5213          *
5214          * If both are flush with the left-hand side or both are the
5215          * same distance away, select the chain.  In this situation the
5216          * chain must have been loaded from the matching blockmap.
5217          */
5218         if ((chain->bref.key <= key_beg && base[i].key <= key_beg) ||
5219             chain->bref.key == base[i].key) {
5220                 KKASSERT(chain->bref.key == base[i].key);
5221                 bref = &chain->bref;
5222                 goto found;
5223         }
5224
5225         /*
5226          * Select the nearer key
5227          */
5228         if (chain->bref.key < base[i].key) {
5229                 bref = &chain->bref;
5230         } else {
5231                 bref = &base[i];
5232                 chain = NULL;
5233         }
5234
5235         /*
5236          * If the bref is out of bounds we've exhausted our search.
5237          */
5238 found:
5239         if (bref->key > key_end) {
5240                 *bresp = NULL;
5241                 chain = NULL;
5242         } else {
5243                 *bresp = bref;
5244         }
5245         return(chain);
5246 }
5247
5248 /*
5249  * Locate the specified block array element and delete it.  The element
5250  * must exist.
5251  *
5252  * The spin lock on the related chain must be held.
5253  *
5254  * NOTE: live_count was adjusted when the chain was deleted, so it does not
5255  *       need to be adjusted when we commit the media change.
5256  */
5257 void
5258 hammer2_base_delete(hammer2_chain_t *parent,
5259                     hammer2_blockref_t *base, int count,
5260                     hammer2_chain_t *chain)
5261 {
5262         hammer2_blockref_t *elm = &chain->bref;
5263         hammer2_blockref_t *scan;
5264         hammer2_key_t key_next;
5265         int i;
5266
5267         /*
5268          * Delete element.  Expect the element to exist.
5269          *
5270          * XXX see caller, flush code not yet sophisticated enough to prevent
5271          *     re-flushed in some cases.
5272          */
5273         key_next = 0; /* max range */
5274         i = hammer2_base_find(parent, base, count, &key_next,
5275                               elm->key, elm->key);
5276         scan = &base[i];
5277         if (i == count || scan->type == 0 ||
5278             scan->key != elm->key ||
5279             ((chain->flags & HAMMER2_CHAIN_BMAPUPD) == 0 &&
5280              scan->keybits != elm->keybits)) {
5281                 hammer2_spin_unex(&parent->core.spin);
5282                 panic("delete base %p element not found at %d/%d elm %p\n",
5283                       base, i, count, elm);
5284                 return;
5285         }
5286
5287         /*
5288          * Update stats and zero the entry.
5289          *
5290          * NOTE: Handle radix == 0 (0 bytes) case.
5291          */
5292         if ((int)(scan->data_off & HAMMER2_OFF_MASK_RADIX)) {
5293                 parent->bref.embed.stats.data_count -= (hammer2_off_t)1 <<
5294                                 (int)(scan->data_off & HAMMER2_OFF_MASK_RADIX);
5295         }
5296         switch(scan->type) {
5297         case HAMMER2_BREF_TYPE_INODE:
5298                 --parent->bref.embed.stats.inode_count;
5299                 /* fall through */
5300         case HAMMER2_BREF_TYPE_DATA:
5301                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5302                         atomic_set_int(&chain->flags,
5303                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5304                 } else {
5305                         if (parent->bref.leaf_count)
5306                                 --parent->bref.leaf_count;
5307                 }
5308                 /* fall through */
5309         case HAMMER2_BREF_TYPE_INDIRECT:
5310                 if (scan->type != HAMMER2_BREF_TYPE_DATA) {
5311                         parent->bref.embed.stats.data_count -=
5312                                 scan->embed.stats.data_count;
5313                         parent->bref.embed.stats.inode_count -=
5314                                 scan->embed.stats.inode_count;
5315                 }
5316                 if (scan->type == HAMMER2_BREF_TYPE_INODE)
5317                         break;
5318                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5319                         atomic_set_int(&chain->flags,
5320                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5321                 } else {
5322                         if (parent->bref.leaf_count <= scan->leaf_count)
5323                                 parent->bref.leaf_count = 0;
5324                         else
5325                                 parent->bref.leaf_count -= scan->leaf_count;
5326                 }
5327                 break;
5328         case HAMMER2_BREF_TYPE_DIRENT:
5329                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5330                         atomic_set_int(&chain->flags,
5331                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5332                 } else {
5333                         if (parent->bref.leaf_count)
5334                                 --parent->bref.leaf_count;
5335                 }
5336         default:
5337                 break;
5338         }
5339
5340         bzero(scan, sizeof(*scan));
5341
5342         /*
5343          * We can only optimize parent->core.live_zero for live chains.
5344          */
5345         if (parent->core.live_zero == i + 1) {
5346                 while (--i >= 0 && base[i].type == 0)
5347                         ;
5348                 parent->core.live_zero = i + 1;
5349         }
5350
5351         /*
5352          * Clear appropriate blockmap flags in chain.
5353          */
5354         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_BMAPPED |
5355                                         HAMMER2_CHAIN_BMAPUPD);
5356 }
5357
5358 /*
5359  * Insert the specified element.  The block array must not already have the
5360  * element and must have space available for the insertion.
5361  *
5362  * The spin lock on the related chain must be held.
5363  *
5364  * NOTE: live_count was adjusted when the chain was deleted, so it does not
5365  *       need to be adjusted when we commit the media change.
5366  */
5367 void
5368 hammer2_base_insert(hammer2_chain_t *parent,
5369                     hammer2_blockref_t *base, int count,
5370                     hammer2_chain_t *chain, hammer2_blockref_t *elm)
5371 {
5372         hammer2_key_t key_next;
5373         hammer2_key_t xkey;
5374         int i;
5375         int j;
5376         int k;
5377         int l;
5378         int u = 1;
5379
5380         /*
5381          * Insert new element.  Expect the element to not already exist
5382          * unless we are replacing it.
5383          *
5384          * XXX see caller, flush code not yet sophisticated enough to prevent
5385          *     re-flushed in some cases.
5386          */
5387         key_next = 0; /* max range */
5388         i = hammer2_base_find(parent, base, count, &key_next,
5389                               elm->key, elm->key);
5390
5391         /*
5392          * Shortcut fill optimization, typical ordered insertion(s) may not
5393          * require a search.
5394          */
5395         KKASSERT(i >= 0 && i <= count);
5396
5397         /*
5398          * Set appropriate blockmap flags in chain (if not NULL)
5399          */
5400         if (chain)
5401                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
5402
5403         /*
5404          * Update stats and zero the entry
5405          */
5406         if ((int)(elm->data_off & HAMMER2_OFF_MASK_RADIX)) {
5407                 parent->bref.embed.stats.data_count += (hammer2_off_t)1 <<
5408                                 (int)(elm->data_off & HAMMER2_OFF_MASK_RADIX);
5409         }
5410         switch(elm->type) {
5411         case HAMMER2_BREF_TYPE_INODE:
5412                 ++parent->bref.embed.stats.inode_count;
5413                 /* fall through */
5414         case HAMMER2_BREF_TYPE_DATA:
5415                 if (parent->bref.leaf_count != HAMMER2_BLOCKREF_LEAF_MAX)
5416                         ++parent->bref.leaf_count;
5417                 /* fall through */
5418         case HAMMER2_BREF_TYPE_INDIRECT:
5419                 if (elm->type != HAMMER2_BREF_TYPE_DATA) {
5420                         parent->bref.embed.stats.data_count +=
5421                                 elm->embed.stats.data_count;
5422                         parent->bref.embed.stats.inode_count +=
5423                                 elm->embed.stats.inode_count;
5424                 }
5425                 if (elm->type == HAMMER2_BREF_TYPE_INODE)
5426                         break;
5427                 if (parent->bref.leaf_count + elm->leaf_count <
5428                     HAMMER2_BLOCKREF_LEAF_MAX) {
5429                         parent->bref.leaf_count += elm->leaf_count;
5430                 } else {
5431                         parent->bref.leaf_count = HAMMER2_BLOCKREF_LEAF_MAX;
5432                 }
5433                 break;
5434         case HAMMER2_BREF_TYPE_DIRENT:
5435                 if (parent->bref.leaf_count != HAMMER2_BLOCKREF_LEAF_MAX)
5436                         ++parent->bref.leaf_count;
5437                 break;
5438         default:
5439                 break;
5440         }
5441
5442
5443         /*
5444          * We can only optimize parent->core.live_zero for live chains.
5445          */
5446         if (i == count && parent->core.live_zero < count) {
5447                 i = parent->core.live_zero++;
5448                 base[i] = *elm;
5449                 return;
5450         }
5451
5452         xkey = elm->key + ((hammer2_key_t)1 << elm->keybits) - 1;
5453         if (i != count && (base[i].key < elm->key || xkey >= base[i].key)) {
5454                 hammer2_spin_unex(&parent->core.spin);
5455                 panic("insert base %p overlapping elements at %d elm %p\n",
5456                       base, i, elm);
5457         }
5458
5459         /*
5460          * Try to find an empty slot before or after.
5461          */
5462         j = i;
5463         k = i;
5464         while (j > 0 || k < count) {
5465                 --j;
5466                 if (j >= 0 && base[j].type == 0) {
5467                         if (j == i - 1) {
5468                                 base[j] = *elm;
5469                         } else {
5470                                 bcopy(&base[j+1], &base[j],
5471                                       (i - j - 1) * sizeof(*base));
5472                                 base[i - 1] = *elm;
5473                         }
5474                         goto validate;
5475                 }
5476                 ++k;
5477                 if (k < count && base[k].type == 0) {
5478                         bcopy(&base[i], &base[i+1],
5479                               (k - i) * sizeof(hammer2_blockref_t));
5480                         base[i] = *elm;
5481
5482                         /*
5483                          * We can only update parent->core.live_zero for live
5484                          * chains.
5485                          */
5486                         if (parent->core.live_zero <= k)
5487                                 parent->core.live_zero = k + 1;
5488                         u = 2;
5489                         goto validate;
5490                 }
5491         }
5492         panic("hammer2_base_insert: no room!");
5493
5494         /*
5495          * Debugging
5496          */
5497 validate:
5498         key_next = 0;
5499         for (l = 0; l < count; ++l) {
5500                 if (base[l].type) {
5501                         key_next = base[l].key +
5502                                    ((hammer2_key_t)1 << base[l].keybits) - 1;
5503                         break;
5504                 }
5505         }
5506         while (++l < count) {
5507                 if (base[l].type) {
5508                         if (base[l].key <= key_next)
5509                                 panic("base_insert %d %d,%d,%d fail %p:%d", u, i, j, k, base, l);
5510                         key_next = base[l].key +
5511                                    ((hammer2_key_t)1 << base[l].keybits) - 1;
5512
5513                 }
5514         }
5515
5516 }
5517
5518 #if 0
5519
5520 /*
5521  * Sort the blockref array for the chain.  Used by the flush code to
5522  * sort the blockref[] array.
5523  *
5524  * The chain must be exclusively locked AND spin-locked.
5525  */
5526 typedef hammer2_blockref_t *hammer2_blockref_p;
5527
5528 static
5529 int
5530 hammer2_base_sort_callback(const void *v1, const void *v2)
5531 {
5532         hammer2_blockref_p bref1 = *(const hammer2_blockref_p *)v1;
5533         hammer2_blockref_p bref2 = *(const hammer2_blockref_p *)v2;
5534
5535         /*
5536          * Make sure empty elements are placed at the end of the array
5537          */
5538         if (bref1->type == 0) {
5539                 if (bref2->type == 0)
5540                         return(0);
5541                 return(1);
5542         } else if (bref2->type == 0) {
5543                 return(-1);
5544         }
5545
5546         /*
5547          * Sort by key
5548          */
5549         if (bref1->key < bref2->key)
5550                 return(-1);
5551         if (bref1->key > bref2->key)
5552                 return(1);
5553         return(0);
5554 }
5555
5556 void
5557 hammer2_base_sort(hammer2_chain_t *chain)
5558 {
5559         hammer2_blockref_t *base;
5560         int count;
5561
5562         switch(chain->bref.type) {
5563         case HAMMER2_BREF_TYPE_INODE:
5564                 /*
5565                  * Special shortcut for embedded data returns the inode
5566                  * itself.  Callers must detect this condition and access
5567                  * the embedded data (the strategy code does this for us).
5568                  *
5569                  * This is only applicable to regular files and softlinks.
5570                  */
5571                 if (chain->data->ipdata.meta.op_flags &
5572                     HAMMER2_OPFLAG_DIRECTDATA) {
5573                         return;
5574                 }
5575                 base = &chain->data->ipdata.u.blockset.blockref[0];
5576                 count = HAMMER2_SET_COUNT;
5577                 break;
5578         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
5579         case HAMMER2_BREF_TYPE_INDIRECT:
5580                 /*
5581                  * Optimize indirect blocks in the INITIAL state to avoid
5582                  * I/O.
5583                  */
5584                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) == 0);
5585                 base = &chain->data->npdata[0];
5586                 count = chain->bytes / sizeof(hammer2_blockref_t);
5587                 break;
5588         case HAMMER2_BREF_TYPE_VOLUME:
5589                 base = &chain->data->voldata.sroot_blockset.blockref[0];
5590                 count = HAMMER2_SET_COUNT;
5591                 break;
5592         case HAMMER2_BREF_TYPE_FREEMAP:
5593                 base = &chain->data->blkset.blockref[0];
5594                 count = HAMMER2_SET_COUNT;
5595                 break;
5596         default:
5597                 kprintf("hammer2_chain_lookup: unrecognized "
5598                         "blockref(A) type: %d",
5599                         chain->bref.type);
5600                 while (1)
5601                         tsleep(&base, 0, "dead", 0);
5602                 panic("hammer2_chain_lookup: unrecognized "
5603                       "blockref(A) type: %d",
5604                       chain->bref.type);
5605                 base = NULL;    /* safety */
5606                 count = 0;      /* safety */
5607         }
5608         kqsort(base, count, sizeof(*base), hammer2_base_sort_callback);
5609 }
5610
5611 #endif
5612
5613 /*
5614  * Chain memory management
5615  */
5616 void
5617 hammer2_chain_wait(hammer2_chain_t *chain)
5618 {
5619         tsleep(chain, 0, "chnflw", 1);
5620 }
5621
5622 const hammer2_media_data_t *
5623 hammer2_chain_rdata(hammer2_chain_t *chain)
5624 {
5625         KKASSERT(chain->data != NULL);
5626         return (chain->data);
5627 }
5628
5629 hammer2_media_data_t *
5630 hammer2_chain_wdata(hammer2_chain_t *chain)
5631 {
5632         KKASSERT(chain->data != NULL);
5633         return (chain->data);
5634 }
5635
5636 /*
5637  * Set the check data for a chain.  This can be a heavy-weight operation
5638  * and typically only runs on-flush.  For file data check data is calculated
5639  * when the logical buffers are flushed.
5640  */
5641 void
5642 hammer2_chain_setcheck(hammer2_chain_t *chain, void *bdata)
5643 {
5644         chain->bref.flags &= ~HAMMER2_BREF_FLAG_ZERO;
5645
5646         switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
5647         case HAMMER2_CHECK_NONE:
5648                 break;
5649         case HAMMER2_CHECK_DISABLED:
5650                 break;
5651         case HAMMER2_CHECK_ISCSI32:
5652                 chain->bref.check.iscsi32.value =
5653                         hammer2_icrc32(bdata, chain->bytes);
5654                 break;
5655         case HAMMER2_CHECK_XXHASH64:
5656                 chain->bref.check.xxhash64.value =
5657                         XXH64(bdata, chain->bytes, XXH_HAMMER2_SEED);
5658                 break;
5659         case HAMMER2_CHECK_SHA192:
5660                 {
5661                         SHA256_CTX hash_ctx;
5662                         union {
5663                                 uint8_t digest[SHA256_DIGEST_LENGTH];
5664                                 uint64_t digest64[SHA256_DIGEST_LENGTH/8];
5665                         } u;
5666
5667                         SHA256_Init(&hash_ctx);
5668                         SHA256_Update(&hash_ctx, bdata, chain->bytes);
5669                         SHA256_Final(u.digest, &hash_ctx);
5670                         u.digest64[2] ^= u.digest64[3];
5671                         bcopy(u.digest,
5672                               chain->bref.check.sha192.data,
5673                               sizeof(chain->bref.check.sha192.data));
5674                 }
5675                 break;
5676         case HAMMER2_CHECK_FREEMAP:
5677                 chain->bref.check.freemap.icrc32 =
5678                         hammer2_icrc32(bdata, chain->bytes);
5679                 break;
5680         default:
5681                 kprintf("hammer2_chain_setcheck: unknown check type %02x\n",
5682                         chain->bref.methods);
5683                 break;
5684         }
5685 }
5686
5687 int
5688 hammer2_chain_testcheck(hammer2_chain_t *chain, void *bdata)
5689 {
5690         uint32_t check32;
5691         uint64_t check64;
5692         int r;
5693
5694         if (chain->bref.flags & HAMMER2_BREF_FLAG_ZERO)
5695                 return 1;
5696
5697         switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
5698         case HAMMER2_CHECK_NONE:
5699                 r = 1;
5700                 break;
5701         case HAMMER2_CHECK_DISABLED:
5702                 r = 1;
5703                 break;
5704         case HAMMER2_CHECK_ISCSI32:
5705                 check32 = hammer2_icrc32(bdata, chain->bytes);
5706                 r = (chain->bref.check.iscsi32.value == check32);
5707                 if (r == 0) {
5708                         kprintf("chain %016jx.%02x meth=%02x CHECK FAIL "
5709                                 "(flags=%08x, bref/data %08x/%08x)\n",
5710                                 chain->bref.data_off,
5711                                 chain->bref.type,
5712                                 chain->bref.methods,
5713                                 chain->flags,
5714                                 chain->bref.check.iscsi32.value,
5715                                 check32);
5716                 }
5717                 hammer2_process_icrc32 += chain->bytes;
5718                 break;
5719         case HAMMER2_CHECK_XXHASH64:
5720                 check64 = XXH64(bdata, chain->bytes, XXH_HAMMER2_SEED);
5721                 r = (chain->bref.check.xxhash64.value == check64);
5722                 if (r == 0) {
5723                         kprintf("chain %016jx.%02x key=%016jx "
5724                                 "meth=%02x CHECK FAIL "
5725                                 "(flags=%08x, bref/data %016jx/%016jx)\n",
5726                                 chain->bref.data_off,
5727                                 chain->bref.type,
5728                                 chain->bref.key,
5729                                 chain->bref.methods,
5730                                 chain->flags,
5731                                 chain->bref.check.xxhash64.value,
5732                                 check64);
5733                 }
5734                 hammer2_process_xxhash64 += chain->bytes;
5735                 break;
5736         case HAMMER2_CHECK_SHA192:
5737                 {
5738                         SHA256_CTX hash_ctx;
5739                         union {
5740                                 uint8_t digest[SHA256_DIGEST_LENGTH];
5741                                 uint64_t digest64[SHA256_DIGEST_LENGTH/8];
5742                         } u;
5743
5744                         SHA256_Init(&hash_ctx);
5745                         SHA256_Update(&hash_ctx, bdata, chain->bytes);
5746                         SHA256_Final(u.digest, &hash_ctx);
5747                         u.digest64[2] ^= u.digest64[3];
5748                         if (bcmp(u.digest,
5749                                  chain->bref.check.sha192.data,
5750                                  sizeof(chain->bref.check.sha192.data)) == 0) {
5751                                 r = 1;
5752                         } else {
5753                                 r = 0;
5754                                 kprintf("chain %016jx.%02x meth=%02x "
5755                                         "CHECK FAIL\n",
5756                                         chain->bref.data_off,
5757                                         chain->bref.type,
5758                                         chain->bref.methods);
5759                         }
5760                 }
5761                 break;
5762         case HAMMER2_CHECK_FREEMAP:
5763                 r = (chain->bref.check.freemap.icrc32 ==
5764                      hammer2_icrc32(bdata, chain->bytes));
5765                 if (r == 0) {
5766                         kprintf("chain %016jx.%02x meth=%02x "
5767                                 "CHECK FAIL\n",
5768                                 chain->bref.data_off,
5769                                 chain->bref.type,
5770                                 chain->bref.methods);
5771                         kprintf("freemap.icrc %08x icrc32 %08x (%d)\n",
5772                                 chain->bref.check.freemap.icrc32,
5773                                 hammer2_icrc32(bdata, chain->bytes),
5774                                                chain->bytes);
5775                         if (chain->dio)
5776                                 kprintf("dio %p buf %016jx,%d bdata %p/%p\n",
5777                                         chain->dio, chain->dio->bp->b_loffset,
5778                                         chain->dio->bp->b_bufsize, bdata,
5779                                         chain->dio->bp->b_data);
5780                 }
5781
5782                 break;
5783         default:
5784                 kprintf("hammer2_chain_setcheck: unknown check type %02x\n",
5785                         chain->bref.methods);
5786                 r = 1;
5787                 break;
5788         }
5789         return r;
5790 }
5791
5792 /*
5793  * Acquire the chain and parent representing the specified inode for the
5794  * device at the specified cluster index.
5795  *
5796  * The flags passed in are LOOKUP flags, not RESOLVE flags.
5797  *
5798  * If we are unable to locate the hardlink, INVAL is returned and *chainp
5799  * will be NULL.  *parentp may still be set error or not, or NULL if the
5800  * parent itself could not be resolved.
5801  *
5802  * Caller must pass-in a valid (and locked), or NULL *parentp or *chainp.
5803  * This function replaces *parentp and *chainp.  Generally speaking, if
5804  * the caller found a directory entry and wants the inode, the caller should
5805  * pass the parent,chain representing the directory entry so this function
5806  * can dispose of it properly to avoid any possible lock order reversals.
5807  */
5808 int
5809 hammer2_chain_inode_find(hammer2_pfs_t *pmp, hammer2_key_t inum,
5810                          int clindex, int flags,
5811                          hammer2_chain_t **parentp, hammer2_chain_t **chainp)
5812 {
5813         hammer2_chain_t *parent;
5814         hammer2_chain_t *rchain;
5815         hammer2_key_t key_dummy;
5816         int resolve_flags;
5817         int error;
5818
5819         resolve_flags = (flags & HAMMER2_LOOKUP_SHARED) ?
5820                         HAMMER2_RESOLVE_SHARED : 0;
5821
5822         /*
5823          * Caller expects us to replace these.
5824          */
5825         if (*chainp) {
5826                 hammer2_chain_unlock(*chainp);
5827                 hammer2_chain_drop(*chainp);
5828                 *chainp = NULL;
5829         }
5830         if (*parentp) {
5831                 hammer2_chain_unlock(*parentp);
5832                 hammer2_chain_drop(*parentp);
5833                 *parentp = NULL;
5834         }
5835
5836         /*
5837          * Inodes hang off of the iroot (bit 63 is clear, differentiating
5838          * inodes from root directory entries in the key lookup).
5839          */
5840         parent = hammer2_inode_chain(pmp->iroot, clindex, resolve_flags);
5841         rchain = NULL;
5842         if (parent) {
5843                 rchain = hammer2_chain_lookup(&parent, &key_dummy,
5844                                               inum, inum,
5845                                               &error, flags);
5846         } else {
5847                 error = HAMMER2_ERROR_EIO;
5848         }
5849         *parentp = parent;
5850         *chainp = rchain;
5851
5852         return error;
5853 }
5854
5855 /*
5856  * Used by the bulkscan code to snapshot the synchronized storage for
5857  * a volume, allowing it to be scanned concurrently against normal
5858  * operation.
5859  */
5860 hammer2_chain_t *
5861 hammer2_chain_bulksnap(hammer2_dev_t *hmp)
5862 {
5863         hammer2_chain_t *copy;
5864
5865         copy = hammer2_chain_alloc(hmp, hmp->spmp, &hmp->vchain.bref);
5866         copy->data = kmalloc(sizeof(copy->data->voldata),
5867                              hmp->mchain,
5868                              M_WAITOK | M_ZERO);
5869         hammer2_voldata_lock(hmp);
5870         copy->data->voldata = hmp->volsync;
5871         hammer2_voldata_unlock(hmp);
5872
5873         return copy;
5874 }
5875
5876 void
5877 hammer2_chain_bulkdrop(hammer2_chain_t *copy)
5878 {
5879         KKASSERT(copy->bref.type == HAMMER2_BREF_TYPE_VOLUME);
5880         KKASSERT(copy->data);
5881         kfree(copy->data, copy->hmp->mchain);
5882         copy->data = NULL;
5883         atomic_add_long(&hammer2_chain_allocs, -1);
5884         hammer2_chain_drop(copy);
5885 }
5886
5887 /*
5888  * Returns non-zero if the chain (INODE or DIRENT) matches the
5889  * filename.
5890  */
5891 int
5892 hammer2_chain_dirent_test(hammer2_chain_t *chain, const char *name,
5893                           size_t name_len)
5894 {
5895         const hammer2_inode_data_t *ripdata;
5896         const hammer2_dirent_head_t *den;
5897
5898         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
5899                 ripdata = &chain->data->ipdata;
5900                 if (ripdata->meta.name_len == name_len &&
5901                     bcmp(ripdata->filename, name, name_len) == 0) {
5902                         return 1;
5903                 }
5904         }
5905         if (chain->bref.type == HAMMER2_BREF_TYPE_DIRENT &&
5906            chain->bref.embed.dirent.namlen == name_len) {
5907                 den = &chain->bref.embed.dirent;
5908                 if (name_len > sizeof(chain->bref.check.buf) &&
5909                     bcmp(chain->data->buf, name, name_len) == 0) {
5910                         return 1;
5911                 }
5912                 if (name_len <= sizeof(chain->bref.check.buf) &&
5913                     bcmp(chain->bref.check.buf, name, name_len) == 0) {
5914                         return 1;
5915                 }
5916         }
5917         return 0;
5918 }