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 void hammer2_chain_rename_obref(hammer2_chain_t **parentp,
  72                 hammer2_chain_t *chain, hammer2_tid_t mtid,
  73                 int flags, hammer2_blockref_t *obref);
  74 static int hammer2_chain_delete_obref(hammer2_chain_t *parent,
  75                 hammer2_chain_t *chain,
  76                 hammer2_tid_t mtid, int flags,
  77                 hammer2_blockref_t *obref);
  78 static hammer2_io_t *hammer2_chain_drop_data(hammer2_chain_t *chain);
  79 static hammer2_chain_t *hammer2_combined_find(
  80                 hammer2_chain_t *parent,
  81                 hammer2_blockref_t *base, int count,
  82                 hammer2_key_t *key_nextp,
  83                 hammer2_key_t key_beg, hammer2_key_t key_end,
  84                 hammer2_blockref_t **bresp);
  85
  86 static struct krate krate_h2me = { .freq = 1 };
  87
  88 /*
  89  * Basic RBTree for chains (core->rbtree and core->dbtree).  Chains cannot
  90  * overlap in the RB trees.  Deleted chains are moved from rbtree to either
  91  * dbtree or to dbq.
  92  *
  93  * Chains in delete-duplicate sequences can always iterate through core_entry
  94  * to locate the live version of the chain.
  95  */
  96 RB_GENERATE(hammer2_chain_tree, hammer2_chain, rbnode, hammer2_chain_cmp);
  97
  98 int
  99 hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2)
 100 {
 101         hammer2_key_t c1_beg;
 102         hammer2_key_t c1_end;
 103         hammer2_key_t c2_beg;
 104         hammer2_key_t c2_end;
 105
 106         /*
 107          * Compare chains.  Overlaps are not supposed to happen and catch
 108          * any software issues early we count overlaps as a match.
 109          */
 110         c1_beg = chain1->bref.key;
 111         c1_end = c1_beg + ((hammer2_key_t)1 << chain1->bref.keybits) - 1;
 112         c2_beg = chain2->bref.key;
 113         c2_end = c2_beg + ((hammer2_key_t)1 << chain2->bref.keybits) - 1;
 114
 115         if (c1_end < c2_beg)    /* fully to the left */
 116                 return(-1);
 117         if (c1_beg > c2_end)    /* fully to the right */
 118                 return(1);
 119         return(0);              /* overlap (must not cross edge boundary) */
 120 }
 121
 122 /*
 123  * Assert that a chain has no media data associated with it.
 124  */
 125 static __inline void
 126 hammer2_chain_assert_no_data(hammer2_chain_t *chain)
 127 {
 128         KKASSERT(chain->dio == NULL);
 129         if (chain->bref.type != HAMMER2_BREF_TYPE_VOLUME &&
 130             chain->bref.type != HAMMER2_BREF_TYPE_FREEMAP &&
 131             chain->data) {
 132                 panic("hammer2_assert_no_data: chain %p still has data", chain);
 133         }
 134 }
 135
 136 /*
 137  * Make a chain visible to the flusher.  The flusher operates using a top-down
 138  * recursion based on the ONFLUSH flag.  It locates MODIFIED and UPDATE chains,
 139  * flushes them, and updates blocks back to the volume root.
 140  *
 141  * This routine sets the ONFLUSH flag upward from the triggering chain until
 142  * it hits an inode root or the volume root.  Inode chains serve as inflection
 143  * points, requiring the flusher to bridge across trees.  Inodes include
 144  * regular inodes, PFS roots (pmp->iroot), and the media super root
 145  * (spmp->iroot).
 146  */
 147 void
 148 hammer2_chain_setflush(hammer2_chain_t *chain)
 149 {
 150         hammer2_chain_t *parent;
 151
 152         if ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
 153                 hammer2_spin_sh(&chain->core.spin);
 154                 while ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
 155                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONFLUSH);
 156                         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
 157                                 break;
 158                         if ((parent = chain->parent) == NULL)
 159                                 break;
 160                         hammer2_spin_sh(&parent->core.spin);
 161                         hammer2_spin_unsh(&chain->core.spin);
 162                         chain = parent;
 163                 }
 164                 hammer2_spin_unsh(&chain->core.spin);
 165         }
 166 }
 167
 168 /*
 169  * Allocate a new disconnected chain element representing the specified
 170  * bref.  chain->refs is set to 1 and the passed bref is copied to
 171  * chain->bref.  chain->bytes is derived from the bref.
 172  *
 173  * chain->pmp inherits pmp unless the chain is an inode (other than the
 174  * super-root inode).
 175  *
 176  * NOTE: Returns a referenced but unlocked (because there is no core) chain.
 177  */
 178 hammer2_chain_t *
 179 hammer2_chain_alloc(hammer2_dev_t *hmp, hammer2_pfs_t *pmp,
 180                     hammer2_blockref_t *bref)
 181 {
 182         hammer2_chain_t *chain;
 183         u_int bytes;
 184
 185         /*
 186          * Special case - radix of 0 indicates a chain that does not
 187          * need a data reference (context is completely embedded in the
 188          * bref).
 189          */
 190         if ((int)(bref->data_off & HAMMER2_OFF_MASK_RADIX))
 191                 bytes = 1U << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
 192         else
 193                 bytes = 0;
 194
 195         atomic_add_long(&hammer2_chain_allocs, 1);
 196
 197         /*
 198          * Construct the appropriate system structure.
 199          */
 200         switch(bref->type) {
 201         case HAMMER2_BREF_TYPE_DIRENT:
 202         case HAMMER2_BREF_TYPE_INODE:
 203         case HAMMER2_BREF_TYPE_INDIRECT:
 204         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 205         case HAMMER2_BREF_TYPE_DATA:
 206         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
 207                 /*
 208                  * Chain's are really only associated with the hmp but we
 209                  * maintain a pmp association for per-mount memory tracking
 210                  * purposes.  The pmp can be NULL.
 211                  */
 212                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
 213                 break;
 214         case HAMMER2_BREF_TYPE_VOLUME:
 215         case HAMMER2_BREF_TYPE_FREEMAP:
 216                 /*
 217                  * Only hammer2_chain_bulksnap() calls this function with these
 218                  * types.
 219                  */
 220                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
 221                 break;
 222         default:
 223                 chain = NULL;
 224                 panic("hammer2_chain_alloc: unrecognized blockref type: %d",
 225                       bref->type);
 226         }
 227
 228         /*
 229          * Initialize the new chain structure.  pmp must be set to NULL for
 230          * chains belonging to the super-root topology of a device mount.
 231          */
 232         if (pmp == hmp->spmp)
 233                 chain->pmp = NULL;
 234         else
 235                 chain->pmp = pmp;
 236
 237         chain->hmp = hmp;
 238         chain->bref = *bref;
 239         chain->bytes = bytes;
 240         chain->refs = 1;
 241         chain->flags = HAMMER2_CHAIN_ALLOCATED;
 242         lockinit(&chain->diolk, "chdio", 0, 0);
 243
 244         /*
 245          * Set the PFS boundary flag if this chain represents a PFS root.
 246          */
 247         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
 248                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_PFSBOUNDARY);
 249         hammer2_chain_core_init(chain);
 250
 251         return (chain);
 252 }
 253
 254 /*
 255  * Initialize a chain's core structure.  This structure used to be allocated
 256  * but is now embedded.
 257  *
 258  * The core is not locked.  No additional refs on the chain are made.
 259  * (trans) must not be NULL if (core) is not NULL.
 260  */
 261 void
 262 hammer2_chain_core_init(hammer2_chain_t *chain)
 263 {
 264         /*
 265          * Fresh core under nchain (no multi-homing of ochain's
 266          * sub-tree).
 267          */
 268         RB_INIT(&chain->core.rbtree);   /* live chains */
 269         hammer2_mtx_init(&chain->lock, "h2chain");
 270 }
 271
 272 /*
 273  * Add a reference to a chain element, preventing its destruction.
 274  *
 275  * (can be called with spinlock held)
 276  */
 277 void
 278 hammer2_chain_ref(hammer2_chain_t *chain)
 279 {
 280         if (atomic_fetchadd_int(&chain->refs, 1) == 0) {
 281                 /*
 282                  * Just flag that the chain was used and should be recycled
 283                  * on the LRU if it encounters it later.
 284                  */
 285                 if (chain->flags & HAMMER2_CHAIN_ONLRU)
 286                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_LRUHINT);
 287
 288 #if 0
 289                 /*
 290                  * REMOVED - reduces contention, lru_list is more heuristical
 291                  * now.
 292                  *
 293                  * 0->non-zero transition must ensure that chain is removed
 294                  * from the LRU list.
 295                  *
 296                  * NOTE: Already holding lru_spin here so we cannot call
 297                  *       hammer2_chain_ref() to get it off lru_list, do
 298                  *       it manually.
 299                  */
 300                 if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 301                         hammer2_pfs_t *pmp = chain->pmp;
 302                         hammer2_spin_ex(&pmp->lru_spin);
 303                         if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 304                                 atomic_add_int(&pmp->lru_count, -1);
 305                                 atomic_clear_int(&chain->flags,
 306                                                  HAMMER2_CHAIN_ONLRU);
 307                                 TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 308                         }
 309                         hammer2_spin_unex(&pmp->lru_spin);
 310                 }
 311 #endif
 312         }
 313 }
 314
 315 /*
 316  * Ref a locked chain and force the data to be held across an unlock.
 317  * Chain must be currently locked.  The user of the chain who desires
 318  * to release the hold must call hammer2_chain_lock_unhold() to relock
 319  * and unhold the chain, then unlock normally, or may simply call
 320  * hammer2_chain_drop_unhold() (which is safer against deadlocks).
 321  */
 322 void
 323 hammer2_chain_ref_hold(hammer2_chain_t *chain)
 324 {
 325         atomic_add_int(&chain->lockcnt, 1);
 326         hammer2_chain_ref(chain);
 327 }
 328
 329 /*
 330  * Insert the chain in the core rbtree.
 331  *
 332  * Normal insertions are placed in the live rbtree.  Insertion of a deleted
 333  * chain is a special case used by the flush code that is placed on the
 334  * unstaged deleted list to avoid confusing the live view.
 335  */
 336 #define HAMMER2_CHAIN_INSERT_SPIN       0x0001
 337 #define HAMMER2_CHAIN_INSERT_LIVE       0x0002
 338 #define HAMMER2_CHAIN_INSERT_RACE       0x0004
 339
 340 static
 341 int
 342 hammer2_chain_insert(hammer2_chain_t *parent, hammer2_chain_t *chain,
 343                      int flags, int generation)
 344 {
 345         hammer2_chain_t *xchain;
 346         int error = 0;
 347
 348         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
 349                 hammer2_spin_ex(&parent->core.spin);
 350
 351         /*
 352          * Interlocked by spinlock, check for race
 353          */
 354         if ((flags & HAMMER2_CHAIN_INSERT_RACE) &&
 355             parent->core.generation != generation) {
 356                 error = HAMMER2_ERROR_EAGAIN;
 357                 goto failed;
 358         }
 359
 360         /*
 361          * Insert chain
 362          */
 363         xchain = RB_INSERT(hammer2_chain_tree, &parent->core.rbtree, chain);
 364         KASSERT(xchain == NULL,
 365                 ("hammer2_chain_insert: collision %p %p (key=%016jx)",
 366                 chain, xchain, chain->bref.key));
 367         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
 368         chain->parent = parent;
 369         ++parent->core.chain_count;
 370         ++parent->core.generation;      /* XXX incs for _get() too, XXX */
 371
 372         /*
 373          * We have to keep track of the effective live-view blockref count
 374          * so the create code knows when to push an indirect block.
 375          */
 376         if (flags & HAMMER2_CHAIN_INSERT_LIVE)
 377                 atomic_add_int(&parent->core.live_count, 1);
 378 failed:
 379         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
 380                 hammer2_spin_unex(&parent->core.spin);
 381         return error;
 382 }
 383
 384 /*
 385  * Drop the caller's reference to the chain.  When the ref count drops to
 386  * zero this function will try to disassociate the chain from its parent and
 387  * deallocate it, then recursely drop the parent using the implied ref
 388  * from the chain's chain->parent.
 389  *
 390  * Nobody should own chain's mutex on the 1->0 transition, unless this drop
 391  * races an acquisition by another cpu.  Therefore we can loop if we are
 392  * unable to acquire the mutex, and refs is unlikely to be 1 unless we again
 393  * race against another drop.
 394  */
 395 static hammer2_chain_t *hammer2_chain_lastdrop(hammer2_chain_t *chain,
 396                                 int depth);
 397 static void hammer2_chain_lru_flush(hammer2_pfs_t *pmp);
 398
 399 void
 400 hammer2_chain_drop(hammer2_chain_t *chain)
 401 {
 402         u_int refs;
 403
 404         if (hammer2_debug & 0x200000)
 405                 Debugger("drop");
 406
 407         KKASSERT(chain->refs > 0);
 408
 409         while (chain) {
 410                 refs = chain->refs;
 411                 cpu_ccfence();
 412                 KKASSERT(refs > 0);
 413
 414                 if (refs == 1) {
 415                         if (hammer2_mtx_ex_try(&chain->lock) == 0)
 416                                 chain = hammer2_chain_lastdrop(chain, 0);
 417                         /* retry the same chain, or chain from lastdrop */
 418                 } else {
 419                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
 420                                 break;
 421                         /* retry the same chain */
 422                 }
 423                 cpu_pause();
 424         }
 425 }
 426
 427 /*
 428  * Unhold a held and probably not-locked chain, ensure that the data is
 429  * dropped on the 1->0 transition of lockcnt by obtaining an exclusive
 430  * lock and then simply unlocking the chain.
 431  */
 432 void
 433 hammer2_chain_unhold(hammer2_chain_t *chain)
 434 {
 435         u_int lockcnt;
 436         int iter = 0;
 437
 438         for (;;) {
 439                 lockcnt = chain->lockcnt;
 440                 cpu_ccfence();
 441                 if (lockcnt > 1) {
 442                         if (atomic_cmpset_int(&chain->lockcnt,
 443                                               lockcnt, lockcnt - 1)) {
 444                                 break;
 445                         }
 446                 } else if (hammer2_mtx_ex_try(&chain->lock) == 0) {
 447                         hammer2_chain_unlock(chain);
 448                         break;
 449                 } else {
 450                         /*
 451                          * This situation can easily occur on SMP due to
 452                          * the gap inbetween the 1->0 transition and the
 453                          * final unlock.  We cannot safely block on the
 454                          * mutex because lockcnt might go above 1.
 455                          *
 456                          * XXX Sleep for one tick if it takes too long.
 457                          */
 458                         if (++iter > 1000) {
 459                                 if (iter > 1000 + hz) {
 460                                         kprintf("hammer2: h2race1 %p\n", chain);
 461                                         iter = 1000;
 462                                 }
 463                                 tsleep(&iter, 0, "h2race1", 1);
 464                         }
 465                         cpu_pause();
 466                 }
 467         }
 468 }
 469
 470 void
 471 hammer2_chain_drop_unhold(hammer2_chain_t *chain)
 472 {
 473         hammer2_chain_unhold(chain);
 474         hammer2_chain_drop(chain);
 475 }
 476
 477 void
 478 hammer2_chain_rehold(hammer2_chain_t *chain)
 479 {
 480         hammer2_chain_lock(chain, HAMMER2_RESOLVE_SHARED);
 481         atomic_add_int(&chain->lockcnt, 1);
 482         hammer2_chain_unlock(chain);
 483 }
 484
 485 /*
 486  * Handles the (potential) last drop of chain->refs from 1->0.  Called with
 487  * the mutex exclusively locked, refs == 1, and lockcnt 0.  SMP races are
 488  * possible against refs and lockcnt.  We must dispose of the mutex on chain.
 489  *
 490  * This function returns an unlocked chain for recursive drop or NULL.  It
 491  * can return the same chain if it determines it has raced another ref.
 492  *
 493  * --
 494  *
 495  * When two chains need to be recursively dropped we use the chain we
 496  * would otherwise free to placehold the additional chain.  It's a bit
 497  * convoluted but we can't just recurse without potentially blowing out
 498  * the kernel stack.
 499  *
 500  * The chain cannot be freed if it has any children.
 501  * The chain cannot be freed if flagged MODIFIED unless we can dispose of it.
 502  * The chain cannot be freed if flagged UPDATE unless we can dispose of it.
 503  * Any dedup registration can remain intact.
 504  *
 505  * The core spinlock is allowed to nest child-to-parent (not parent-to-child).
 506  */
 507 static
 508 hammer2_chain_t *
 509 hammer2_chain_lastdrop(hammer2_chain_t *chain, int depth)
 510 {
 511         hammer2_pfs_t *pmp;
 512         hammer2_dev_t *hmp;
 513         hammer2_chain_t *parent;
 514         hammer2_chain_t *rdrop;
 515
 516         /*
 517          * We need chain's spinlock to interlock the sub-tree test.
 518          * We already have chain's mutex, protecting chain->parent.
 519          *
 520          * Remember that chain->refs can be in flux.
 521          */
 522         hammer2_spin_ex(&chain->core.spin);
 523
 524         if (chain->parent != NULL) {
 525                 /*
 526                  * If the chain has a parent the UPDATE bit prevents scrapping
 527                  * as the chain is needed to properly flush the parent.  Try
 528                  * to complete the 1->0 transition and return NULL.  Retry
 529                  * (return chain) if we are unable to complete the 1->0
 530                  * transition, else return NULL (nothing more to do).
 531                  *
 532                  * If the chain has a parent the MODIFIED bit prevents
 533                  * scrapping.
 534                  *
 535                  * Chains with UPDATE/MODIFIED are *not* put on the LRU list!
 536                  */
 537                 if (chain->flags & (HAMMER2_CHAIN_UPDATE |
 538                                     HAMMER2_CHAIN_MODIFIED)) {
 539                         if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 540                                 hammer2_spin_unex(&chain->core.spin);
 541                                 hammer2_chain_assert_no_data(chain);
 542                                 hammer2_mtx_unlock(&chain->lock);
 543                                 chain = NULL;
 544                         } else {
 545                                 hammer2_spin_unex(&chain->core.spin);
 546                                 hammer2_mtx_unlock(&chain->lock);
 547                         }
 548                         return (chain);
 549                 }
 550                 /* spinlock still held */
 551         } else if (chain->bref.type == HAMMER2_BREF_TYPE_VOLUME ||
 552                    chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP) {
 553                 /*
 554                  * Retain the static vchain and fchain.  Clear bits that
 555                  * are not relevant.  Do not clear the MODIFIED bit,
 556                  * and certainly do not put it on the delayed-flush queue.
 557                  */
 558                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 559         } else {
 560                 /*
 561                  * The chain has no parent and can be flagged for destruction.
 562                  * Since it has no parent, UPDATE can also be cleared.
 563                  */
 564                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
 565                 if (chain->flags & HAMMER2_CHAIN_UPDATE)
 566                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 567
 568                 /*
 569                  * If the chain has children we must propagate the DESTROY
 570                  * flag downward and rip the disconnected topology apart.
 571                  * This is accomplished by calling hammer2_flush() on the
 572                  * chain.
 573                  *
 574                  * Any dedup is already handled by the underlying DIO, so
 575                  * we do not have to specifically flush it here.
 576                  */
 577                 if (chain->core.chain_count) {
 578                         hammer2_spin_unex(&chain->core.spin);
 579                         hammer2_flush(chain, HAMMER2_FLUSH_TOP |
 580                                              HAMMER2_FLUSH_ALL);
 581                         hammer2_mtx_unlock(&chain->lock);
 582
 583                         return(chain);  /* retry drop */
 584                 }
 585
 586                 /*
 587                  * Otherwise we can scrap the MODIFIED bit if it is set,
 588                  * and continue along the freeing path.
 589                  *
 590                  * Be sure to clean-out any dedup bits.  Without a parent
 591                  * this chain will no longer be visible to the flush code.
 592                  * Easy check data_off to avoid the volume root.
 593                  */
 594                 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
 595                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 596                         atomic_add_long(&hammer2_count_modified_chains, -1);
 597                         if (chain->pmp)
 598                                 hammer2_pfs_memory_wakeup(chain->pmp);
 599                 }
 600                 /* spinlock still held */
 601         }
 602
 603         /* spinlock still held */
 604
 605         /*
 606          * If any children exist we must leave the chain intact with refs == 0.
 607          * They exist because chains are retained below us which have refs or
 608          * may require flushing.
 609          *
 610          * Retry (return chain) if we fail to transition the refs to 0, else
 611          * return NULL indication nothing more to do.
 612          *
 613          * Chains with children are NOT put on the LRU list.
 614          */
 615         if (chain->core.chain_count) {
 616                 if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 617                         hammer2_spin_unex(&chain->core.spin);
 618                         hammer2_chain_assert_no_data(chain);
 619                         hammer2_mtx_unlock(&chain->lock);
 620                         chain = NULL;
 621                 } else {
 622                         hammer2_spin_unex(&chain->core.spin);
 623                         hammer2_mtx_unlock(&chain->lock);
 624                 }
 625                 return (chain);
 626         }
 627         /* spinlock still held */
 628         /* no chains left under us */
 629
 630         /*
 631          * chain->core has no children left so no accessors can get to our
 632          * chain from there.  Now we have to lock the parent core to interlock
 633          * remaining possible accessors that might bump chain's refs before
 634          * we can safely drop chain's refs with intent to free the chain.
 635          */
 636         hmp = chain->hmp;
 637         pmp = chain->pmp;       /* can be NULL */
 638         rdrop = NULL;
 639
 640         parent = chain->parent;
 641
 642         /*
 643          * WARNING! chain's spin lock is still held here, and other spinlocks
 644          *          will be acquired and released in the code below.  We
 645          *          cannot be making fancy procedure calls!
 646          */
 647
 648         /*
 649          * We can cache the chain if it is associated with a pmp
 650          * and not flagged as being destroyed or requesting a full
 651          * release.  In this situation the chain is not removed
 652          * from its parent, i.e. it can still be looked up.
 653          *
 654          * We intentionally do not cache DATA chains because these
 655          * were likely used to load data into the logical buffer cache
 656          * and will not be accessed again for some time.
 657          */
 658         if ((chain->flags &
 659              (HAMMER2_CHAIN_DESTROY | HAMMER2_CHAIN_RELEASE)) == 0 &&
 660             chain->pmp &&
 661             chain->bref.type != HAMMER2_BREF_TYPE_DATA) {
 662                 if (parent)
 663                         hammer2_spin_ex(&parent->core.spin);
 664                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 665                         /*
 666                          * 1->0 transition failed, retry.  Do not drop
 667                          * the chain's data yet!
 668                          */
 669                         if (parent)
 670                                 hammer2_spin_unex(&parent->core.spin);
 671                         hammer2_spin_unex(&chain->core.spin);
 672                         hammer2_mtx_unlock(&chain->lock);
 673
 674                         return(chain);
 675                 }
 676
 677                 /*
 678                  * Success
 679                  */
 680                 hammer2_chain_assert_no_data(chain);
 681
 682                 /*
 683                  * Make sure we are on the LRU list, clean up excessive
 684                  * LRU entries.  We can only really drop one but there might
 685                  * be other entries that we can remove from the lru_list
 686                  * without dropping.
 687                  *
 688                  * NOTE: HAMMER2_CHAIN_ONLRU may only be safely set when
 689                  *       chain->core.spin AND pmp->lru_spin are held, but
 690                  *       can be safely cleared only holding pmp->lru_spin.
 691                  */
 692                 if ((chain->flags & HAMMER2_CHAIN_ONLRU) == 0) {
 693                         hammer2_spin_ex(&pmp->lru_spin);
 694                         if ((chain->flags & HAMMER2_CHAIN_ONLRU) == 0) {
 695                                 atomic_set_int(&chain->flags,
 696                                                HAMMER2_CHAIN_ONLRU);
 697                                 TAILQ_INSERT_TAIL(&pmp->lru_list,
 698                                                   chain, lru_node);
 699                                 atomic_add_int(&pmp->lru_count, 1);
 700                         }
 701                         if (pmp->lru_count < HAMMER2_LRU_LIMIT)
 702                                 depth = 1;      /* disable lru_list flush */
 703                         hammer2_spin_unex(&pmp->lru_spin);
 704                 } else {
 705                         /* disable lru flush */
 706                         depth = 1;
 707                 }
 708
 709                 if (parent) {
 710                         hammer2_spin_unex(&parent->core.spin);
 711                         parent = NULL;  /* safety */
 712                 }
 713                 hammer2_spin_unex(&chain->core.spin);
 714                 hammer2_mtx_unlock(&chain->lock);
 715
 716                 /*
 717                  * lru_list hysteresis (see above for depth overrides).
 718                  * Note that depth also prevents excessive lastdrop recursion.
 719                  */
 720                 if (depth == 0)
 721                         hammer2_chain_lru_flush(pmp);
 722
 723                 return NULL;
 724                 /* NOT REACHED */
 725         }
 726
 727         /*
 728          * Make sure we are not on the LRU list.
 729          */
 730         if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 731                 hammer2_spin_ex(&pmp->lru_spin);
 732                 if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 733                         atomic_add_int(&pmp->lru_count, -1);
 734                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 735                         TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 736                 }
 737                 hammer2_spin_unex(&pmp->lru_spin);
 738         }
 739
 740         /*
 741          * Spinlock the parent and try to drop the last ref on chain.
 742          * On success determine if we should dispose of the chain
 743          * (remove the chain from its parent, etc).
 744          *
 745          * (normal core locks are top-down recursive but we define
 746          * core spinlocks as bottom-up recursive, so this is safe).
 747          */
 748         if (parent) {
 749                 hammer2_spin_ex(&parent->core.spin);
 750                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 751                         /*
 752                          * 1->0 transition failed, retry.
 753                          */
 754                         hammer2_spin_unex(&parent->core.spin);
 755                         hammer2_spin_unex(&chain->core.spin);
 756                         hammer2_mtx_unlock(&chain->lock);
 757
 758                         return(chain);
 759                 }
 760
 761                 /*
 762                  * 1->0 transition successful, parent spin held to prevent
 763                  * new lookups, chain spinlock held to protect parent field.
 764                  * Remove chain from the parent.
 765                  *
 766                  * If the chain is being removed from the parent's btree but
 767                  * is not bmapped, we have to adjust live_count downward.  If
 768                  * it is bmapped then the blockref is retained in the parent
 769                  * as is its associated live_count.  This case can occur when
 770                  * a chain added to the topology is unable to flush and is
 771                  * then later deleted.
 772                  */
 773                 if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
 774                         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) &&
 775                             (chain->flags & HAMMER2_CHAIN_BMAPPED) == 0) {
 776                                 atomic_add_int(&parent->core.live_count, -1);
 777                         }
 778                         RB_REMOVE(hammer2_chain_tree,
 779                                   &parent->core.rbtree, chain);
 780                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
 781                         --parent->core.chain_count;
 782                         chain->parent = NULL;
 783                 }
 784
 785                 /*
 786                  * If our chain was the last chain in the parent's core the
 787                  * core is now empty and its parent might have to be
 788                  * re-dropped if it has 0 refs.
 789                  */
 790                 if (parent->core.chain_count == 0) {
 791                         rdrop = parent;
 792                         atomic_add_int(&rdrop->refs, 1);
 793                         /*
 794                         if (atomic_cmpset_int(&rdrop->refs, 0, 1) == 0)
 795                                 rdrop = NULL;
 796                         */
 797                 }
 798                 hammer2_spin_unex(&parent->core.spin);
 799                 parent = NULL;  /* safety */
 800                 /* FALL THROUGH */
 801         } else {
 802                 /*
 803                  * No-parent case.
 804                  */
 805                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 806                         /*
 807                          * 1->0 transition failed, retry.
 808                          */
 809                         hammer2_spin_unex(&parent->core.spin);
 810                         hammer2_spin_unex(&chain->core.spin);
 811                         hammer2_mtx_unlock(&chain->lock);
 812
 813                         return(chain);
 814                 }
 815         }
 816
 817         /*
 818          * Successful 1->0 transition, no parent, no children... no way for
 819          * anyone to ref this chain any more.  We can clean-up and free it.
 820          *
 821          * We still have the core spinlock, and core's chain_count is 0.
 822          * Any parent spinlock is gone.
 823          */
 824         hammer2_spin_unex(&chain->core.spin);
 825         hammer2_chain_assert_no_data(chain);
 826         hammer2_mtx_unlock(&chain->lock);
 827         KKASSERT(RB_EMPTY(&chain->core.rbtree) &&
 828                  chain->core.chain_count == 0);
 829
 830         /*
 831          * All locks are gone, no pointers remain to the chain, finish
 832          * freeing it.
 833          */
 834         KKASSERT((chain->flags & (HAMMER2_CHAIN_UPDATE |
 835                                   HAMMER2_CHAIN_MODIFIED)) == 0);
 836
 837         /*
 838          * Once chain resources are gone we can use the now dead chain
 839          * structure to placehold what might otherwise require a recursive
 840          * drop, because we have potentially two things to drop and can only
 841          * return one directly.
 842          */
 843         if (chain->flags & HAMMER2_CHAIN_ALLOCATED) {
 844                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ALLOCATED);
 845                 chain->hmp = NULL;
 846                 kfree(chain, hmp->mchain);
 847         }
 848
 849         /*
 850          * Possible chaining loop when parent re-drop needed.
 851          */
 852         return(rdrop);
 853 }
 854
 855 /*
 856  * Heuristical flush of the LRU, try to reduce the number of entries
 857  * on the LRU to (HAMMER2_LRU_LIMIT * 2 / 3).  This procedure is called
 858  * only when lru_count exceeds HAMMER2_LRU_LIMIT.
 859  */
 860 static
 861 void
 862 hammer2_chain_lru_flush(hammer2_pfs_t *pmp)
 863 {
 864         hammer2_chain_t *chain;
 865
 866 again:
 867         chain = NULL;
 868         hammer2_spin_ex(&pmp->lru_spin);
 869         while (pmp->lru_count > HAMMER2_LRU_LIMIT * 2 / 3) {
 870                 /*
 871                  * Pick a chain off the lru_list, just recycle it quickly
 872                  * if LRUHINT is set (the chain was ref'd but left on
 873                  * the lru_list, so cycle to the end).
 874                  */
 875                 chain = TAILQ_FIRST(&pmp->lru_list);
 876                 TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 877
 878                 if (chain->flags & HAMMER2_CHAIN_LRUHINT) {
 879                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_LRUHINT);
 880                         TAILQ_INSERT_TAIL(&pmp->lru_list, chain, lru_node);
 881                         chain = NULL;
 882                         continue;
 883                 }
 884
 885                 /*
 886                  * Ok, we are off the LRU.  We must adjust refs before we
 887                  * can safely clear the ONLRU flag.
 888                  */
 889                 atomic_add_int(&pmp->lru_count, -1);
 890                 if (atomic_cmpset_int(&chain->refs, 0, 1)) {
 891                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 892                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
 893                         break;
 894                 }
 895                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 896                 chain = NULL;
 897         }
 898         hammer2_spin_unex(&pmp->lru_spin);
 899         if (chain == NULL)
 900                 return;
 901
 902         /*
 903          * If we picked a chain off the lru list we may be able to lastdrop
 904          * it.  Use a depth of 1 to prevent excessive lastdrop recursion.
 905          */
 906         while (chain) {
 907                 u_int refs;
 908
 909                 refs = chain->refs;
 910                 cpu_ccfence();
 911                 KKASSERT(refs > 0);
 912
 913                 if (refs == 1) {
 914                         if (hammer2_mtx_ex_try(&chain->lock) == 0)
 915                                 chain = hammer2_chain_lastdrop(chain, 1);
 916                         /* retry the same chain, or chain from lastdrop */
 917                 } else {
 918                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
 919                                 break;
 920                         /* retry the same chain */
 921                 }
 922                 cpu_pause();
 923         }
 924         goto again;
 925 }
 926
 927 /*
 928  * On last lock release.
 929  */
 930 static hammer2_io_t *
 931 hammer2_chain_drop_data(hammer2_chain_t *chain)
 932 {
 933         hammer2_io_t *dio;
 934
 935         if ((dio = chain->dio) != NULL) {
 936                 chain->dio = NULL;
 937                 chain->data = NULL;
 938         } else {
 939                 switch(chain->bref.type) {
 940                 case HAMMER2_BREF_TYPE_VOLUME:
 941                 case HAMMER2_BREF_TYPE_FREEMAP:
 942                         break;
 943                 default:
 944                         if (chain->data != NULL) {
 945                                 hammer2_spin_unex(&chain->core.spin);
 946                                 panic("chain data not null: "
 947                                       "chain %p bref %016jx.%02x "
 948                                       "refs %d parent %p dio %p data %p",
 949                                       chain, chain->bref.data_off,
 950                                       chain->bref.type, chain->refs,
 951                                       chain->parent,
 952                                       chain->dio, chain->data);
 953                         }
 954                         KKASSERT(chain->data == NULL);
 955                         break;
 956                 }
 957         }
 958         return dio;
 959 }
 960
 961 /*
 962  * Lock a referenced chain element, acquiring its data with I/O if necessary,
 963  * and specify how you would like the data to be resolved.
 964  *
 965  * If an I/O or other fatal error occurs, chain->error will be set to non-zero.
 966  *
 967  * The lock is allowed to recurse, multiple locking ops will aggregate
 968  * the requested resolve types.  Once data is assigned it will not be
 969  * removed until the last unlock.
 970  *
 971  * HAMMER2_RESOLVE_NEVER - Do not resolve the data element.
 972  *                         (typically used to avoid device/logical buffer
 973  *                          aliasing for data)
 974  *
 975  * HAMMER2_RESOLVE_MAYBE - Do not resolve data elements for chains in
 976  *                         the INITIAL-create state (indirect blocks only).
 977  *
 978  *                         Do not resolve data elements for DATA chains.
 979  *                         (typically used to avoid device/logical buffer
 980  *                          aliasing for data)
 981  *
 982  * HAMMER2_RESOLVE_ALWAYS- Always resolve the data element.
 983  *
 984  * HAMMER2_RESOLVE_SHARED- (flag) The chain is locked shared, otherwise
 985  *                         it will be locked exclusive.
 986  *
 987  * HAMMER2_RESOLVE_NONBLOCK- (flag) The chain is locked non-blocking.  If
 988  *                         the lock fails, EAGAIN is returned.
 989  *
 990  * NOTE: Embedded elements (volume header, inodes) are always resolved
 991  *       regardless.
 992  *
 993  * NOTE: Specifying HAMMER2_RESOLVE_ALWAYS on a newly-created non-embedded
 994  *       element will instantiate and zero its buffer, and flush it on
 995  *       release.
 996  *
 997  * NOTE: (data) elements are normally locked RESOLVE_NEVER or RESOLVE_MAYBE
 998  *       so as not to instantiate a device buffer, which could alias against
 999  *       a logical file buffer.  However, if ALWAYS is specified the
1000  *       device buffer will be instantiated anyway.
1001  *
1002  * NOTE: The return value is always 0 unless NONBLOCK is specified, in which
1003  *       case it can be either 0 or EAGAIN.
1004  *
1005  * WARNING! This function blocks on I/O if data needs to be fetched.  This
1006  *          blocking can run concurrent with other compatible lock holders
1007  *          who do not need data returning.  The lock is not upgraded to
1008  *          exclusive during a data fetch, a separate bit is used to
1009  *          interlock I/O.  However, an exclusive lock holder can still count
1010  *          on being interlocked against an I/O fetch managed by a shared
1011  *          lock holder.
1012  */
1013 int
1014 hammer2_chain_lock(hammer2_chain_t *chain, int how)
1015 {
1016         KKASSERT(chain->refs > 0);
1017
1018         if (how & HAMMER2_RESOLVE_NONBLOCK) {
1019                 /*
1020                  * We still have to bump lockcnt before acquiring the lock,
1021                  * even for non-blocking operation, because the unlock code
1022                  * live-loops on lockcnt == 1 when dropping the last lock.
1023                  *
1024                  * If the non-blocking operation fails we have to use an
1025                  * unhold sequence to undo the mess.
1026                  *
1027                  * NOTE: LOCKAGAIN must always succeed without blocking,
1028                  *       even if NONBLOCK is specified.
1029                  */
1030                 atomic_add_int(&chain->lockcnt, 1);
1031                 if (how & HAMMER2_RESOLVE_SHARED) {
1032                         if (how & HAMMER2_RESOLVE_LOCKAGAIN) {
1033                                 hammer2_mtx_sh_again(&chain->lock);
1034                         } else {
1035                                 if (hammer2_mtx_sh_try(&chain->lock) != 0) {
1036                                         hammer2_chain_unhold(chain);
1037                                         return EAGAIN;
1038                                 }
1039                         }
1040                 } else {
1041                         if (hammer2_mtx_ex_try(&chain->lock) != 0) {
1042                                 hammer2_chain_unhold(chain);
1043                                 return EAGAIN;
1044                         }
1045                 }
1046                 ++curthread->td_tracker;
1047         } else {
1048                 /*
1049                  * Get the appropriate lock.  If LOCKAGAIN is flagged with
1050                  * SHARED the caller expects a shared lock to already be
1051                  * present and we are giving it another ref.  This case must
1052                  * importantly not block if there is a pending exclusive lock
1053                  * request.
1054                  */
1055                 atomic_add_int(&chain->lockcnt, 1);
1056                 if (how & HAMMER2_RESOLVE_SHARED) {
1057                         if (how & HAMMER2_RESOLVE_LOCKAGAIN) {
1058                                 hammer2_mtx_sh_again(&chain->lock);
1059                         } else {
1060                                 hammer2_mtx_sh(&chain->lock);
1061                         }
1062                 } else {
1063                         hammer2_mtx_ex(&chain->lock);
1064                 }
1065                 ++curthread->td_tracker;
1066         }
1067
1068         /*
1069          * If we already have a valid data pointer make sure the data is
1070          * synchronized to the current cpu, and then no further action is
1071          * necessary.
1072          */
1073         if (chain->data) {
1074                 if (chain->dio)
1075                         hammer2_io_bkvasync(chain->dio);
1076                 return 0;
1077         }
1078
1079         /*
1080          * Do we have to resolve the data?  This is generally only
1081          * applicable to HAMMER2_BREF_TYPE_DATA which is special-cased.
1082          * Other BREF types expects the data to be there.
1083          */
1084         switch(how & HAMMER2_RESOLVE_MASK) {
1085         case HAMMER2_RESOLVE_NEVER:
1086                 return 0;
1087         case HAMMER2_RESOLVE_MAYBE:
1088                 if (chain->flags & HAMMER2_CHAIN_INITIAL)
1089                         return 0;
1090                 if (chain->bref.type == HAMMER2_BREF_TYPE_DATA)
1091                         return 0;
1092 #if 0
1093                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE)
1094                         return 0;
1095                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF)
1096                         return 0;
1097 #endif
1098                 /* fall through */
1099         case HAMMER2_RESOLVE_ALWAYS:
1100         default:
1101                 break;
1102         }
1103
1104         /*
1105          * Caller requires data
1106          */
1107         hammer2_chain_load_data(chain);
1108
1109         return 0;
1110 }
1111
1112 /*
1113  * Lock the chain, retain the hold, and drop the data persistence count.
1114  * The data should remain valid because we never transitioned lockcnt
1115  * through 0.
1116  */
1117 void
1118 hammer2_chain_lock_unhold(hammer2_chain_t *chain, int how)
1119 {
1120         hammer2_chain_lock(chain, how);
1121         atomic_add_int(&chain->lockcnt, -1);
1122 }
1123
1124 #if 0
1125 /*
1126  * Downgrade an exclusive chain lock to a shared chain lock.
1127  *
1128  * NOTE: There is no upgrade equivalent due to the ease of
1129  *       deadlocks in that direction.
1130  */
1131 void
1132 hammer2_chain_lock_downgrade(hammer2_chain_t *chain)
1133 {
1134         hammer2_mtx_downgrade(&chain->lock);
1135 }
1136 #endif
1137
1138 /*
1139  * Issue I/O and install chain->data.  Caller must hold a chain lock, lock
1140  * may be of any type.
1141  *
1142  * Once chain->data is set it cannot be disposed of until all locks are
1143  * released.
1144  *
1145  * Make sure the data is synchronized to the current cpu.
1146  */
1147 void
1148 hammer2_chain_load_data(hammer2_chain_t *chain)
1149 {
1150         hammer2_blockref_t *bref;
1151         hammer2_dev_t *hmp;
1152         hammer2_io_t *dio;
1153         char *bdata;
1154         int error;
1155
1156         /*
1157          * Degenerate case, data already present, or chain has no media
1158          * reference to load.
1159          */
1160         KKASSERT(chain->lock.mtx_lock & MTX_MASK);
1161         if (chain->data) {
1162                 if (chain->dio)
1163                         hammer2_io_bkvasync(chain->dio);
1164                 return;
1165         }
1166         if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0)
1167                 return;
1168
1169         hmp = chain->hmp;
1170         KKASSERT(hmp != NULL);
1171
1172         /*
1173          * Gain the IOINPROG bit, interlocked block.
1174          */
1175         for (;;) {
1176                 u_int oflags;
1177                 u_int nflags;
1178
1179                 oflags = chain->flags;
1180                 cpu_ccfence();
1181                 if (oflags & HAMMER2_CHAIN_IOINPROG) {
1182                         nflags = oflags | HAMMER2_CHAIN_IOSIGNAL;
1183                         tsleep_interlock(&chain->flags, 0);
1184                         if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1185                                 tsleep(&chain->flags, PINTERLOCKED,
1186                                         "h2iocw", 0);
1187                         }
1188                         /* retry */
1189                 } else {
1190                         nflags = oflags | HAMMER2_CHAIN_IOINPROG;
1191                         if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1192                                 break;
1193                         }
1194                         /* retry */
1195                 }
1196         }
1197
1198         /*
1199          * We own CHAIN_IOINPROG
1200          *
1201          * Degenerate case if we raced another load.
1202          */
1203         if (chain->data) {
1204                 if (chain->dio)
1205                         hammer2_io_bkvasync(chain->dio);
1206                 goto done;
1207         }
1208
1209         /*
1210          * We must resolve to a device buffer, either by issuing I/O or
1211          * by creating a zero-fill element.  We do not mark the buffer
1212          * dirty when creating a zero-fill element (the hammer2_chain_modify()
1213          * API must still be used to do that).
1214          *
1215          * The device buffer is variable-sized in powers of 2 down
1216          * to HAMMER2_MIN_ALLOC (typically 1K).  A 64K physical storage
1217          * chunk always contains buffers of the same size. (XXX)
1218          *
1219          * The minimum physical IO size may be larger than the variable
1220          * block size.
1221          */
1222         bref = &chain->bref;
1223
1224         /*
1225          * The getblk() optimization can only be used on newly created
1226          * elements if the physical block size matches the request.
1227          */
1228         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1229                 error = hammer2_io_new(hmp, bref->type,
1230                                        bref->data_off, chain->bytes,
1231                                        &chain->dio);
1232         } else {
1233                 error = hammer2_io_bread(hmp, bref->type,
1234                                          bref->data_off, chain->bytes,
1235                                          &chain->dio);
1236                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1237         }
1238         if (error) {
1239                 chain->error = HAMMER2_ERROR_EIO;
1240                 kprintf("hammer2_chain_lock: I/O error %016jx: %d\n",
1241                         (intmax_t)bref->data_off, error);
1242                 hammer2_io_bqrelse(&chain->dio);
1243                 goto done;
1244         }
1245         chain->error = 0;
1246
1247         /*
1248          * This isn't perfect and can be ignored on OSs which do not have
1249          * an indication as to whether a buffer is coming from cache or
1250          * if I/O was actually issued for the read.  TESTEDGOOD will work
1251          * pretty well without the B_IOISSUED logic because chains are
1252          * cached, but in that situation (without B_IOISSUED) it will not
1253          * detect whether a re-read via I/O is corrupted verses the original
1254          * read.
1255          *
1256          * We can't re-run the CRC on every fresh lock.  That would be
1257          * insanely expensive.
1258          *
1259          * If the underlying kernel buffer covers the entire chain we can
1260          * use the B_IOISSUED indication to determine if we have to re-run
1261          * the CRC on chain data for chains that managed to stay cached
1262          * across the kernel disposal of the original buffer.
1263          */
1264         if ((dio = chain->dio) != NULL && dio->bp) {
1265                 struct buf *bp = dio->bp;
1266
1267                 if (dio->psize == chain->bytes &&
1268                     (bp->b_flags & B_IOISSUED)) {
1269                         atomic_clear_int(&chain->flags,
1270                                          HAMMER2_CHAIN_TESTEDGOOD);
1271                         bp->b_flags &= ~B_IOISSUED;
1272                 }
1273         }
1274
1275         /*
1276          * NOTE: A locked chain's data cannot be modified without first
1277          *       calling hammer2_chain_modify().
1278          */
1279
1280         /*
1281          * Clear INITIAL.  In this case we used io_new() and the buffer has
1282          * been zero'd and marked dirty.
1283          *
1284          * NOTE: hammer2_io_data() call issues bkvasync()
1285          */
1286         bdata = hammer2_io_data(chain->dio, chain->bref.data_off);
1287
1288         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1289                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1290                 chain->bref.flags |= HAMMER2_BREF_FLAG_ZERO;
1291         } else if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
1292                 /*
1293                  * check data not currently synchronized due to
1294                  * modification.  XXX assumes data stays in the buffer
1295                  * cache, which might not be true (need biodep on flush
1296                  * to calculate crc?  or simple crc?).
1297                  */
1298         } else if ((chain->flags & HAMMER2_CHAIN_TESTEDGOOD) == 0) {
1299                 if (hammer2_chain_testcheck(chain, bdata) == 0) {
1300                         chain->error = HAMMER2_ERROR_CHECK;
1301                 } else {
1302                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_TESTEDGOOD);
1303                 }
1304         }
1305
1306         /*
1307          * Setup the data pointer, either pointing it to an embedded data
1308          * structure and copying the data from the buffer, or pointing it
1309          * into the buffer.
1310          *
1311          * The buffer is not retained when copying to an embedded data
1312          * structure in order to avoid potential deadlocks or recursions
1313          * on the same physical buffer.
1314          *
1315          * WARNING! Other threads can start using the data the instant we
1316          *          set chain->data non-NULL.
1317          */
1318         switch (bref->type) {
1319         case HAMMER2_BREF_TYPE_VOLUME:
1320         case HAMMER2_BREF_TYPE_FREEMAP:
1321                 /*
1322                  * Copy data from bp to embedded buffer
1323                  */
1324                 panic("hammer2_chain_load_data: unresolved volume header");
1325                 break;
1326         case HAMMER2_BREF_TYPE_DIRENT:
1327                 KKASSERT(chain->bytes != 0);
1328                 /* fall through */
1329         case HAMMER2_BREF_TYPE_INODE:
1330         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1331         case HAMMER2_BREF_TYPE_INDIRECT:
1332         case HAMMER2_BREF_TYPE_DATA:
1333         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1334         default:
1335                 /*
1336                  * Point data at the device buffer and leave dio intact.
1337                  */
1338                 chain->data = (void *)bdata;
1339                 break;
1340         }
1341
1342         /*
1343          * Release HAMMER2_CHAIN_IOINPROG and signal waiters if requested.
1344          */
1345 done:
1346         for (;;) {
1347                 u_int oflags;
1348                 u_int nflags;
1349
1350                 oflags = chain->flags;
1351                 nflags = oflags & ~(HAMMER2_CHAIN_IOINPROG |
1352                                     HAMMER2_CHAIN_IOSIGNAL);
1353                 KKASSERT(oflags & HAMMER2_CHAIN_IOINPROG);
1354                 if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1355                         if (oflags & HAMMER2_CHAIN_IOSIGNAL)
1356                                 wakeup(&chain->flags);
1357                         break;
1358                 }
1359         }
1360 }
1361
1362 /*
1363  * Unlock and deref a chain element.
1364  *
1365  * Remember that the presence of children under chain prevent the chain's
1366  * destruction but do not add additional references, so the dio will still
1367  * be dropped.
1368  */
1369 void
1370 hammer2_chain_unlock(hammer2_chain_t *chain)
1371 {
1372         hammer2_io_t *dio;
1373         u_int lockcnt;
1374         int iter = 0;
1375
1376         --curthread->td_tracker;
1377
1378         /*
1379          * If multiple locks are present (or being attempted) on this
1380          * particular chain we can just unlock, drop refs, and return.
1381          *
1382          * Otherwise fall-through on the 1->0 transition.
1383          */
1384         for (;;) {
1385                 lockcnt = chain->lockcnt;
1386                 KKASSERT(lockcnt > 0);
1387                 cpu_ccfence();
1388                 if (lockcnt > 1) {
1389                         if (atomic_cmpset_int(&chain->lockcnt,
1390                                               lockcnt, lockcnt - 1)) {
1391                                 hammer2_mtx_unlock(&chain->lock);
1392                                 return;
1393                         }
1394                 } else if (hammer2_mtx_upgrade_try(&chain->lock) == 0) {
1395                         /* while holding the mutex exclusively */
1396                         if (atomic_cmpset_int(&chain->lockcnt, 1, 0))
1397                                 break;
1398                 } else {
1399                         /*
1400                          * This situation can easily occur on SMP due to
1401                          * the gap inbetween the 1->0 transition and the
1402                          * final unlock.  We cannot safely block on the
1403                          * mutex because lockcnt might go above 1.
1404                          *
1405                          * XXX Sleep for one tick if it takes too long.
1406                          */
1407                         if (++iter > 1000) {
1408                                 if (iter > 1000 + hz) {
1409                                         kprintf("hammer2: h2race2 %p\n", chain);
1410                                         iter = 1000;
1411                                 }
1412                                 tsleep(&iter, 0, "h2race2", 1);
1413                         }
1414                         cpu_pause();
1415                 }
1416                 /* retry */
1417         }
1418
1419         /*
1420          * Last unlock / mutex upgraded to exclusive.  Drop the data
1421          * reference.
1422          */
1423         dio = hammer2_chain_drop_data(chain);
1424         if (dio)
1425                 hammer2_io_bqrelse(&dio);
1426         hammer2_mtx_unlock(&chain->lock);
1427 }
1428
1429 /*
1430  * Unlock and hold chain data intact
1431  */
1432 void
1433 hammer2_chain_unlock_hold(hammer2_chain_t *chain)
1434 {
1435         atomic_add_int(&chain->lockcnt, 1);
1436         hammer2_chain_unlock(chain);
1437 }
1438
1439 /*
1440  * Helper to obtain the blockref[] array base and count for a chain.
1441  *
1442  * XXX Not widely used yet, various use cases need to be validated and
1443  *     converted to use this function.
1444  */
1445 static
1446 hammer2_blockref_t *
1447 hammer2_chain_base_and_count(hammer2_chain_t *parent, int *countp)
1448 {
1449         hammer2_blockref_t *base;
1450         int count;
1451
1452         if (parent->flags & HAMMER2_CHAIN_INITIAL) {
1453                 base = NULL;
1454
1455                 switch(parent->bref.type) {
1456                 case HAMMER2_BREF_TYPE_INODE:
1457                         count = HAMMER2_SET_COUNT;
1458                         break;
1459                 case HAMMER2_BREF_TYPE_INDIRECT:
1460                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1461                         count = parent->bytes / sizeof(hammer2_blockref_t);
1462                         break;
1463                 case HAMMER2_BREF_TYPE_VOLUME:
1464                         count = HAMMER2_SET_COUNT;
1465                         break;
1466                 case HAMMER2_BREF_TYPE_FREEMAP:
1467                         count = HAMMER2_SET_COUNT;
1468                         break;
1469                 default:
1470                         panic("hammer2_chain_create_indirect: "
1471                               "unrecognized blockref type: %d",
1472                               parent->bref.type);
1473                         count = 0;
1474                         break;
1475                 }
1476         } else {
1477                 switch(parent->bref.type) {
1478                 case HAMMER2_BREF_TYPE_INODE:
1479                         base = &parent->data->ipdata.u.blockset.blockref[0];
1480                         count = HAMMER2_SET_COUNT;
1481                         break;
1482                 case HAMMER2_BREF_TYPE_INDIRECT:
1483                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1484                         base = &parent->data->npdata[0];
1485                         count = parent->bytes / sizeof(hammer2_blockref_t);
1486                         break;
1487                 case HAMMER2_BREF_TYPE_VOLUME:
1488                         base = &parent->data->voldata.
1489                                         sroot_blockset.blockref[0];
1490                         count = HAMMER2_SET_COUNT;
1491                         break;
1492                 case HAMMER2_BREF_TYPE_FREEMAP:
1493                         base = &parent->data->blkset.blockref[0];
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         }
1504         *countp = count;
1505
1506         return base;
1507 }
1508
1509 /*
1510  * This counts the number of live blockrefs in a block array and
1511  * also calculates the point at which all remaining blockrefs are empty.
1512  * This routine can only be called on a live chain.
1513  *
1514  * Caller holds the chain locked, but possibly with a shared lock.  We
1515  * must use an exclusive spinlock to prevent corruption.
1516  *
1517  * NOTE: Flag is not set until after the count is complete, allowing
1518  *       callers to test the flag without holding the spinlock.
1519  *
1520  * NOTE: If base is NULL the related chain is still in the INITIAL
1521  *       state and there are no blockrefs to count.
1522  *
1523  * NOTE: live_count may already have some counts accumulated due to
1524  *       creation and deletion and could even be initially negative.
1525  */
1526 void
1527 hammer2_chain_countbrefs(hammer2_chain_t *chain,
1528                          hammer2_blockref_t *base, int count)
1529 {
1530         hammer2_spin_ex(&chain->core.spin);
1531         if ((chain->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0) {
1532                 if (base) {
1533                         while (--count >= 0) {
1534                                 if (base[count].type)
1535                                         break;
1536                         }
1537                         chain->core.live_zero = count + 1;
1538                         while (count >= 0) {
1539                                 if (base[count].type)
1540                                         atomic_add_int(&chain->core.live_count,
1541                                                        1);
1542                                 --count;
1543                         }
1544                 } else {
1545                         chain->core.live_zero = 0;
1546                 }
1547                 /* else do not modify live_count */
1548                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_COUNTEDBREFS);
1549         }
1550         hammer2_spin_unex(&chain->core.spin);
1551 }
1552
1553 /*
1554  * Resize the chain's physical storage allocation in-place.  This function does
1555  * not usually adjust the data pointer and must be followed by (typically) a
1556  * hammer2_chain_modify() call to copy any old data over and adjust the
1557  * data pointer.
1558  *
1559  * Chains can be resized smaller without reallocating the storage.  Resizing
1560  * larger will reallocate the storage.  Excess or prior storage is reclaimed
1561  * asynchronously at a later time.
1562  *
1563  * An nradix value of 0 is special-cased to mean that the storage should
1564  * be disassociated, that is the chain is being resized to 0 bytes (not 1
1565  * byte).
1566  *
1567  * Must be passed an exclusively locked parent and chain.
1568  *
1569  * This function is mostly used with DATA blocks locked RESOLVE_NEVER in order
1570  * to avoid instantiating a device buffer that conflicts with the vnode data
1571  * buffer.  However, because H2 can compress or encrypt data, the chain may
1572  * have a dio assigned to it in those situations, and they do not conflict.
1573  *
1574  * XXX return error if cannot resize.
1575  */
1576 int
1577 hammer2_chain_resize(hammer2_chain_t *chain,
1578                      hammer2_tid_t mtid, hammer2_off_t dedup_off,
1579                      int nradix, int flags)
1580 {
1581         hammer2_dev_t *hmp;
1582         size_t obytes;
1583         size_t nbytes;
1584         int error;
1585
1586         hmp = chain->hmp;
1587
1588         /*
1589          * Only data and indirect blocks can be resized for now.
1590          * (The volu root, inodes, and freemap elements use a fixed size).
1591          */
1592         KKASSERT(chain != &hmp->vchain);
1593         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1594                  chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
1595                  chain->bref.type == HAMMER2_BREF_TYPE_DIRENT);
1596
1597         /*
1598          * Nothing to do if the element is already the proper size
1599          */
1600         obytes = chain->bytes;
1601         nbytes = (nradix) ? (1U << nradix) : 0;
1602         if (obytes == nbytes)
1603                 return (chain->error);
1604
1605         /*
1606          * Make sure the old data is instantiated so we can copy it.  If this
1607          * is a data block, the device data may be superfluous since the data
1608          * might be in a logical block, but compressed or encrypted data is
1609          * another matter.
1610          *
1611          * NOTE: The modify will set BMAPUPD for us if BMAPPED is set.
1612          */
1613         error = hammer2_chain_modify(chain, mtid, dedup_off, 0);
1614         if (error)
1615                 return error;
1616
1617         /*
1618          * Relocate the block, even if making it smaller (because different
1619          * block sizes may be in different regions).
1620          *
1621          * NOTE: Operation does not copy the data and may only be used
1622          *        to resize data blocks in-place, or directory entry blocks
1623          *        which are about to be modified in some manner.
1624          */
1625         error = hammer2_freemap_alloc(chain, nbytes);
1626         if (error)
1627                 return error;
1628
1629         chain->bytes = nbytes;
1630
1631         /*
1632          * We don't want the followup chain_modify() to try to copy data
1633          * from the old (wrong-sized) buffer.  It won't know how much to
1634          * copy.  This case should only occur during writes when the
1635          * originator already has the data to write in-hand.
1636          */
1637         if (chain->dio) {
1638                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1639                          chain->bref.type == HAMMER2_BREF_TYPE_DIRENT);
1640                 hammer2_io_brelse(&chain->dio);
1641                 chain->data = NULL;
1642         }
1643         return (chain->error);
1644 }
1645
1646 /*
1647  * Set the chain modified so its data can be changed by the caller, or
1648  * install deduplicated data.  The caller must call this routine for each
1649  * set of modifications it makes, even if the chain is already flagged
1650  * MODIFIED.
1651  *
1652  * Sets bref.modify_tid to mtid only if mtid != 0.  Note that bref.modify_tid
1653  * is a CLC (cluster level change) field and is not updated by parent
1654  * propagation during a flush.
1655  *
1656  * Returns an appropriate HAMMER2_ERROR_* code, which will generally reflect
1657  * chain->error except for HAMMER2_ERROR_ENOSPC.  If the allocation fails
1658  * due to no space available, HAMMER2_ERROR_ENOSPC is returned and the chain
1659  * remains unmodified with its old data ref intact and chain->error
1660  * unchanged.
1661  *
1662  *                               Dedup Handling
1663  *
1664  * If the DEDUPABLE flag is set in the chain the storage must be reallocated
1665  * even if the chain is still flagged MODIFIED.  In this case the chain's
1666  * DEDUPABLE flag will be cleared once the new storage has been assigned.
1667  *
1668  * If the caller passes a non-zero dedup_off we will use it to assign the
1669  * new storage.  The MODIFIED flag will be *CLEARED* in this case, and
1670  * DEDUPABLE will be set (NOTE: the UPDATE flag is always set).  The caller
1671  * must not modify the data content upon return.
1672  */
1673 int
1674 hammer2_chain_modify(hammer2_chain_t *chain, hammer2_tid_t mtid,
1675                      hammer2_off_t dedup_off, int flags)
1676 {
1677         hammer2_blockref_t obref;
1678         hammer2_dev_t *hmp;
1679         hammer2_io_t *dio;
1680         int error;
1681         int wasinitial;
1682         int setmodified;
1683         int setupdate;
1684         int newmod;
1685         char *bdata;
1686
1687         hmp = chain->hmp;
1688         obref = chain->bref;
1689         KKASSERT((chain->flags & HAMMER2_CHAIN_FICTITIOUS) == 0);
1690         KKASSERT(chain->lock.mtx_lock & MTX_EXCLUSIVE);
1691
1692         /*
1693          * Data is not optional for freemap chains (we must always be sure
1694          * to copy the data on COW storage allocations).
1695          */
1696         if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
1697             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
1698                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) ||
1699                          (flags & HAMMER2_MODIFY_OPTDATA) == 0);
1700         }
1701
1702         /*
1703          * Data must be resolved if already assigned, unless explicitly
1704          * flagged otherwise.  If we cannot safety load the data the
1705          * modification fails and we return early.
1706          */
1707         if (chain->data == NULL && chain->bytes != 0 &&
1708             (flags & HAMMER2_MODIFY_OPTDATA) == 0 &&
1709             (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
1710                 hammer2_chain_load_data(chain);
1711                 if (chain->error)
1712                         return (chain->error);
1713         }
1714         error = 0;
1715
1716         /*
1717          * Set MODIFIED to indicate that the chain has been modified.  A new
1718          * allocation is required when modifying a chain.
1719          *
1720          * Set UPDATE to ensure that the blockref is updated in the parent.
1721          *
1722          * If MODIFIED is already set determine if we can reuse the assigned
1723          * data block or if we need a new data block.
1724          */
1725         if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0) {
1726                 /*
1727                  * Must set modified bit.
1728                  */
1729                 atomic_add_long(&hammer2_count_modified_chains, 1);
1730                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1731                 hammer2_pfs_memory_inc(chain->pmp);  /* can be NULL */
1732                 setmodified = 1;
1733
1734                 /*
1735                  * We may be able to avoid a copy-on-write if the chain's
1736                  * check mode is set to NONE and the chain's current
1737                  * modify_tid is beyond the last explicit snapshot tid.
1738                  *
1739                  * This implements HAMMER2's overwrite-in-place feature.
1740                  *
1741                  * NOTE! This data-block cannot be used as a de-duplication
1742                  *       source when the check mode is set to NONE.
1743                  */
1744                 if ((chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1745                      chain->bref.type == HAMMER2_BREF_TYPE_DIRENT) &&
1746                     (chain->flags & HAMMER2_CHAIN_INITIAL) == 0 &&
1747                     (chain->flags & HAMMER2_CHAIN_DEDUPABLE) == 0 &&
1748                     HAMMER2_DEC_CHECK(chain->bref.methods) ==
1749                      HAMMER2_CHECK_NONE &&
1750                     chain->pmp &&
1751                     chain->bref.modify_tid >
1752                      chain->pmp->iroot->meta.pfs_lsnap_tid) {
1753                         /*
1754                          * Sector overwrite allowed.
1755                          */
1756                         newmod = 0;
1757                 } else {
1758                         /*
1759                          * Sector overwrite not allowed, must copy-on-write.
1760                          */
1761                         newmod = 1;
1762                 }
1763         } else if (chain->flags & HAMMER2_CHAIN_DEDUPABLE) {
1764                 /*
1765                  * If the modified chain was registered for dedup we need
1766                  * a new allocation.  This only happens for delayed-flush
1767                  * chains (i.e. which run through the front-end buffer
1768                  * cache).
1769                  */
1770                 newmod = 1;
1771                 setmodified = 0;
1772         } else {
1773                 /*
1774                  * Already flagged modified, no new allocation is needed.
1775                  */
1776                 newmod = 0;
1777                 setmodified = 0;
1778         }
1779
1780         /*
1781          * Flag parent update required.
1782          */
1783         if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0) {
1784                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1785                 setupdate = 1;
1786         } else {
1787                 setupdate = 0;
1788         }
1789
1790         /*
1791          * The XOP code returns held but unlocked focus chains.  This
1792          * prevents the chain from being destroyed but does not prevent
1793          * it from being modified.  diolk is used to interlock modifications
1794          * against XOP frontend accesses to the focus.
1795          *
1796          * This allows us to theoretically avoid deadlocking the frontend
1797          * if one of the backends lock up by not formally locking the
1798          * focused chain in the frontend.  In addition, the synchronization
1799          * code relies on this mechanism to avoid deadlocking concurrent
1800          * synchronization threads.
1801          */
1802         lockmgr(&chain->diolk, LK_EXCLUSIVE);
1803
1804         /*
1805          * The modification or re-modification requires an allocation and
1806          * possible COW.  If an error occurs, the previous content and data
1807          * reference is retained and the modification fails.
1808          *
1809          * If dedup_off is non-zero, the caller is requesting a deduplication
1810          * rather than a modification.  The MODIFIED bit is not set and the
1811          * data offset is set to the deduplication offset.  The data cannot
1812          * be modified.
1813          *
1814          * NOTE: The dedup offset is allowed to be in a partially free state
1815          *       and we must be sure to reset it to a fully allocated state
1816          *       to force two bulkfree passes to free it again.
1817          *
1818          * NOTE: Only applicable when chain->bytes != 0.
1819          *
1820          * XXX can a chain already be marked MODIFIED without a data
1821          * assignment?  If not, assert here instead of testing the case.
1822          */
1823         if (chain != &hmp->vchain && chain != &hmp->fchain &&
1824             chain->bytes) {
1825                 if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0 ||
1826                      newmod
1827                 ) {
1828                         /*
1829                          * NOTE: We do not have to remove the dedup
1830                          *       registration because the area is still
1831                          *       allocated and the underlying DIO will
1832                          *       still be flushed.
1833                          */
1834                         if (dedup_off) {
1835                                 chain->bref.data_off = dedup_off;
1836                                 chain->bytes = 1 << (dedup_off &
1837                                                      HAMMER2_OFF_MASK_RADIX);
1838                                 chain->error = 0;
1839                                 atomic_clear_int(&chain->flags,
1840                                                  HAMMER2_CHAIN_MODIFIED);
1841                                 atomic_add_long(&hammer2_count_modified_chains,
1842                                                 -1);
1843                                 if (chain->pmp)
1844                                         hammer2_pfs_memory_wakeup(chain->pmp);
1845                                 hammer2_freemap_adjust(hmp, &chain->bref,
1846                                                 HAMMER2_FREEMAP_DORECOVER);
1847                                 atomic_set_int(&chain->flags,
1848                                                 HAMMER2_CHAIN_DEDUPABLE);
1849                         } else {
1850                                 error = hammer2_freemap_alloc(chain,
1851                                                               chain->bytes);
1852                                 atomic_clear_int(&chain->flags,
1853                                                 HAMMER2_CHAIN_DEDUPABLE);
1854                         }
1855                 }
1856         }
1857
1858         /*
1859          * Stop here if error.  We have to undo any flag bits we might
1860          * have set above.
1861          */
1862         if (error) {
1863                 if (setmodified) {
1864                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1865                         atomic_add_long(&hammer2_count_modified_chains, -1);
1866                         if (chain->pmp)
1867                                 hammer2_pfs_memory_wakeup(chain->pmp);
1868                 }
1869                 if (setupdate) {
1870                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1871                 }
1872                 lockmgr(&chain->diolk, LK_RELEASE);
1873
1874                 return error;
1875         }
1876
1877         /*
1878          * Update mirror_tid and modify_tid.  modify_tid is only updated
1879          * if not passed as zero (during flushes, parent propagation passes
1880          * the value 0).
1881          *
1882          * NOTE: chain->pmp could be the device spmp.
1883          */
1884         chain->bref.mirror_tid = hmp->voldata.mirror_tid + 1;
1885         if (mtid)
1886                 chain->bref.modify_tid = mtid;
1887
1888         /*
1889          * Set BMAPUPD to tell the flush code that an existing blockmap entry
1890          * requires updating as well as to tell the delete code that the
1891          * chain's blockref might not exactly match (in terms of physical size
1892          * or block offset) the one in the parent's blocktable.  The base key
1893          * of course will still match.
1894          */
1895         if (chain->flags & HAMMER2_CHAIN_BMAPPED)
1896                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPUPD);
1897
1898         /*
1899          * Short-cut data blocks which the caller does not need an actual
1900          * data reference to (aka OPTDATA), as long as the chain does not
1901          * already have a data pointer to the data.  This generally means
1902          * that the modifications are being done via the logical buffer cache.
1903          * The INITIAL flag relates only to the device data buffer and thus
1904          * remains unchange in this situation.
1905          *
1906          * This code also handles bytes == 0 (most dirents).
1907          */
1908         if (chain->bref.type == HAMMER2_BREF_TYPE_DATA &&
1909             (flags & HAMMER2_MODIFY_OPTDATA) &&
1910             chain->data == NULL) {
1911                 KKASSERT(chain->dio == NULL);
1912                 goto skip2;
1913         }
1914
1915         /*
1916          * Clearing the INITIAL flag (for indirect blocks) indicates that
1917          * we've processed the uninitialized storage allocation.
1918          *
1919          * If this flag is already clear we are likely in a copy-on-write
1920          * situation but we have to be sure NOT to bzero the storage if
1921          * no data is present.
1922          */
1923         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1924                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1925                 wasinitial = 1;
1926         } else {
1927                 wasinitial = 0;
1928         }
1929
1930         /*
1931          * Instantiate data buffer and possibly execute COW operation
1932          */
1933         switch(chain->bref.type) {
1934         case HAMMER2_BREF_TYPE_VOLUME:
1935         case HAMMER2_BREF_TYPE_FREEMAP:
1936                 /*
1937                  * The data is embedded, no copy-on-write operation is
1938                  * needed.
1939                  */
1940                 KKASSERT(chain->dio == NULL);
1941                 break;
1942         case HAMMER2_BREF_TYPE_DIRENT:
1943                 /*
1944                  * The data might be fully embedded.
1945                  */
1946                 if (chain->bytes == 0) {
1947                         KKASSERT(chain->dio == NULL);
1948                         break;
1949                 }
1950                 /* fall through */
1951         case HAMMER2_BREF_TYPE_INODE:
1952         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1953         case HAMMER2_BREF_TYPE_DATA:
1954         case HAMMER2_BREF_TYPE_INDIRECT:
1955         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1956                 /*
1957                  * Perform the copy-on-write operation
1958                  *
1959                  * zero-fill or copy-on-write depending on whether
1960                  * chain->data exists or not and set the dirty state for
1961                  * the new buffer.  hammer2_io_new() will handle the
1962                  * zero-fill.
1963                  *
1964                  * If a dedup_off was supplied this is an existing block
1965                  * and no COW, copy, or further modification is required.
1966                  */
1967                 KKASSERT(chain != &hmp->vchain && chain != &hmp->fchain);
1968
1969                 if (wasinitial && dedup_off == 0) {
1970                         error = hammer2_io_new(hmp, chain->bref.type,
1971                                                chain->bref.data_off,
1972                                                chain->bytes, &dio);
1973                 } else {
1974                         error = hammer2_io_bread(hmp, chain->bref.type,
1975                                                  chain->bref.data_off,
1976                                                  chain->bytes, &dio);
1977                 }
1978                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1979
1980                 /*
1981                  * If an I/O error occurs make sure callers cannot accidently
1982                  * modify the old buffer's contents and corrupt the filesystem.
1983                  *
1984                  * NOTE: hammer2_io_data() call issues bkvasync()
1985                  */
1986                 if (error) {
1987                         kprintf("hammer2_chain_modify: hmp=%p I/O error\n",
1988                                 hmp);
1989                         chain->error = HAMMER2_ERROR_EIO;
1990                         hammer2_io_brelse(&dio);
1991                         hammer2_io_brelse(&chain->dio);
1992                         chain->data = NULL;
1993                         break;
1994                 }
1995                 chain->error = 0;
1996                 bdata = hammer2_io_data(dio, chain->bref.data_off);
1997
1998                 if (chain->data) {
1999                         /*
2000                          * COW (unless a dedup).
2001                          */
2002                         KKASSERT(chain->dio != NULL);
2003                         if (chain->data != (void *)bdata && dedup_off == 0) {
2004                                 bcopy(chain->data, bdata, chain->bytes);
2005                         }
2006                 } else if (wasinitial == 0) {
2007                         /*
2008                          * We have a problem.  We were asked to COW but
2009                          * we don't have any data to COW with!
2010                          */
2011                         panic("hammer2_chain_modify: having a COW %p\n",
2012                               chain);
2013                 }
2014
2015                 /*
2016                  * Retire the old buffer, replace with the new.  Dirty or
2017                  * redirty the new buffer.
2018                  *
2019                  * WARNING! The system buffer cache may have already flushed
2020                  *          the buffer, so we must be sure to [re]dirty it
2021                  *          for further modification.
2022                  *
2023                  *          If dedup_off was supplied, the caller is not
2024                  *          expected to make any further modification to the
2025                  *          buffer.
2026                  *
2027                  * WARNING! hammer2_get_gdata() assumes dio never transitions
2028                  *          through NULL in order to optimize away unnecessary
2029                  *          diolk operations.
2030                  */
2031                 {
2032                         hammer2_io_t *tio;
2033
2034                         if ((tio = chain->dio) != NULL)
2035                                 hammer2_io_bqrelse(&tio);
2036                         chain->data = (void *)bdata;
2037                         chain->dio = dio;
2038                         if (dedup_off == 0)
2039                                 hammer2_io_setdirty(dio);
2040                 }
2041                 break;
2042         default:
2043                 panic("hammer2_chain_modify: illegal non-embedded type %d",
2044                       chain->bref.type);
2045                 break;
2046
2047         }
2048 skip2:
2049         /*
2050          * setflush on parent indicating that the parent must recurse down
2051          * to us.  Do not call on chain itself which might already have it
2052          * set.
2053          */
2054         if (chain->parent)
2055                 hammer2_chain_setflush(chain->parent);
2056         lockmgr(&chain->diolk, LK_RELEASE);
2057
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  * This call can be made with parent == NULL as long as a non -1 methods
3266  * is supplied.  hmp must also be supplied in this situation (otherwise
3267  * hmp is extracted from the supplied parent).  The chain will be detached
3268  * from the topology.  A later call with both parent and chain can be made
3269  * to attach it.
3270  *
3271  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (*parentp) TO THE INSERTION
3272  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
3273  * FULL.  This typically means that the caller is creating the chain after
3274  * doing a hammer2_chain_lookup().
3275  *
3276  * (*parentp) must be exclusive locked and may be replaced on return
3277  * depending on how much work the function had to do.
3278  *
3279  * (*parentp) must not be errored or this function will assert.
3280  *
3281  * (*chainp) usually starts out NULL and returns the newly created chain,
3282  * but if the caller desires the caller may allocate a disconnected chain
3283  * and pass it in instead.
3284  *
3285  * This function should NOT be used to insert INDIRECT blocks.  It is
3286  * typically used to create/insert inodes and data blocks.
3287  *
3288  * Caller must pass-in an exclusively locked parent the new chain is to
3289  * be inserted under, and optionally pass-in a disconnected, exclusively
3290  * locked chain to insert (else we create a new chain).  The function will
3291  * adjust (*parentp) as necessary, create or connect the chain, and
3292  * return an exclusively locked chain in *chainp.
3293  *
3294  * When creating a PFSROOT inode under the super-root, pmp is typically NULL
3295  * and will be reassigned.
3296  *
3297  * NOTE: returns HAMMER_ERROR_* flags
3298  */
3299 int
3300 hammer2_chain_create(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
3301                      hammer2_dev_t *hmp, hammer2_pfs_t *pmp, int methods,
3302                      hammer2_key_t key, int keybits, int type, size_t bytes,
3303                      hammer2_tid_t mtid, hammer2_off_t dedup_off, int flags)
3304 {
3305         hammer2_chain_t *chain;
3306         hammer2_chain_t *parent;
3307         hammer2_blockref_t *base;
3308         hammer2_blockref_t dummy;
3309         int allocated = 0;
3310         int error = 0;
3311         int count;
3312         int maxloops = 300000;
3313
3314         /*
3315          * Topology may be crossing a PFS boundary.
3316          */
3317         parent = *parentp;
3318         if (parent) {
3319                 KKASSERT(hammer2_mtx_owned(&parent->lock));
3320                 KKASSERT(parent->error == 0);
3321                 hmp = parent->hmp;
3322         }
3323         chain = *chainp;
3324
3325         if (chain == NULL) {
3326                 /*
3327                  * First allocate media space and construct the dummy bref,
3328                  * then allocate the in-memory chain structure.  Set the
3329                  * INITIAL flag for fresh chains which do not have embedded
3330                  * data.
3331                  *
3332                  * XXX for now set the check mode of the child based on
3333                  *     the parent or, if the parent is an inode, the
3334                  *     specification in the inode.
3335                  */
3336                 bzero(&dummy, sizeof(dummy));
3337                 dummy.type = type;
3338                 dummy.key = key;
3339                 dummy.keybits = keybits;
3340                 dummy.data_off = hammer2_getradix(bytes);
3341
3342                 /*
3343                  * Inherit methods from parent by default.  Primarily used
3344                  * for BREF_TYPE_DATA.  Non-data types *must* be set to
3345                  * a non-NONE check algorithm.
3346                  */
3347                 if (methods == -1)
3348                         dummy.methods = parent->bref.methods;
3349                 else
3350                         dummy.methods = (uint8_t)methods;
3351
3352                 if (type != HAMMER2_BREF_TYPE_DATA &&
3353                     HAMMER2_DEC_CHECK(dummy.methods) == HAMMER2_CHECK_NONE) {
3354                         dummy.methods |=
3355                                 HAMMER2_ENC_CHECK(HAMMER2_CHECK_DEFAULT);
3356                 }
3357
3358                 chain = hammer2_chain_alloc(hmp, pmp, &dummy);
3359
3360                 /*
3361                  * Lock the chain manually, chain_lock will load the chain
3362                  * which we do NOT want to do.  (note: chain->refs is set
3363                  * to 1 by chain_alloc() for us, but lockcnt is not).
3364                  */
3365                 chain->lockcnt = 1;
3366                 hammer2_mtx_ex(&chain->lock);
3367                 allocated = 1;
3368                 ++curthread->td_tracker;
3369
3370                 /*
3371                  * Set INITIAL to optimize I/O.  The flag will generally be
3372                  * processed when we call hammer2_chain_modify().
3373                  *
3374                  * Recalculate bytes to reflect the actual media block
3375                  * allocation.  Handle special case radix 0 == 0 bytes.
3376                  */
3377                 bytes = (size_t)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
3378                 if (bytes)
3379                         bytes = (hammer2_off_t)1 << bytes;
3380                 chain->bytes = bytes;
3381
3382                 switch(type) {
3383                 case HAMMER2_BREF_TYPE_VOLUME:
3384                 case HAMMER2_BREF_TYPE_FREEMAP:
3385                         panic("hammer2_chain_create: called with volume type");
3386                         break;
3387                 case HAMMER2_BREF_TYPE_INDIRECT:
3388                         panic("hammer2_chain_create: cannot be used to"
3389                               "create indirect block");
3390                         break;
3391                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3392                         panic("hammer2_chain_create: cannot be used to"
3393                               "create freemap root or node");
3394                         break;
3395                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3396                         KKASSERT(bytes == sizeof(chain->data->bmdata));
3397                         /* fall through */
3398                 case HAMMER2_BREF_TYPE_DIRENT:
3399                 case HAMMER2_BREF_TYPE_INODE:
3400                 case HAMMER2_BREF_TYPE_DATA:
3401                 default:
3402                         /*
3403                          * leave chain->data NULL, set INITIAL
3404                          */
3405                         KKASSERT(chain->data == NULL);
3406                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
3407                         break;
3408                 }
3409         } else {
3410                 /*
3411                  * We are reattaching a previously deleted chain, possibly
3412                  * under a new parent and possibly with a new key/keybits.
3413                  * The chain does not have to be in a modified state.  The
3414                  * UPDATE flag will be set later on in this routine.
3415                  *
3416                  * Do NOT mess with the current state of the INITIAL flag.
3417                  */
3418                 chain->bref.key = key;
3419                 chain->bref.keybits = keybits;
3420                 if (chain->flags & HAMMER2_CHAIN_DELETED)
3421                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3422                 KKASSERT(chain->parent == NULL);
3423         }
3424
3425         /*
3426          * Set the appropriate bref flag if requested.
3427          *
3428          * NOTE! Callers can call this function to move chains without
3429          *       knowing about special flags, so don't clear bref flags
3430          *       here!
3431          */
3432         if (flags & HAMMER2_INSERT_PFSROOT)
3433                 chain->bref.flags |= HAMMER2_BREF_FLAG_PFSROOT;
3434
3435         if (parent == NULL)
3436                 goto skip;
3437
3438         /*
3439          * Calculate how many entries we have in the blockref array and
3440          * determine if an indirect block is required when inserting into
3441          * the parent.
3442          */
3443 again:
3444         if (--maxloops == 0)
3445                 panic("hammer2_chain_create: maxloops");
3446
3447         switch(parent->bref.type) {
3448         case HAMMER2_BREF_TYPE_INODE:
3449                 if ((parent->data->ipdata.meta.op_flags &
3450                      HAMMER2_OPFLAG_DIRECTDATA) != 0) {
3451                         kprintf("hammer2: parent set for direct-data! "
3452                                 "pkey=%016jx ckey=%016jx\n",
3453                                 parent->bref.key,
3454                                 chain->bref.key);
3455                 }
3456                 KKASSERT((parent->data->ipdata.meta.op_flags &
3457                           HAMMER2_OPFLAG_DIRECTDATA) == 0);
3458                 KKASSERT(parent->data != NULL);
3459                 base = &parent->data->ipdata.u.blockset.blockref[0];
3460                 count = HAMMER2_SET_COUNT;
3461                 break;
3462         case HAMMER2_BREF_TYPE_INDIRECT:
3463         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3464                 if (parent->flags & HAMMER2_CHAIN_INITIAL)
3465                         base = NULL;
3466                 else
3467                         base = &parent->data->npdata[0];
3468                 count = parent->bytes / sizeof(hammer2_blockref_t);
3469                 break;
3470         case HAMMER2_BREF_TYPE_VOLUME:
3471                 KKASSERT(parent->data != NULL);
3472                 base = &parent->data->voldata.sroot_blockset.blockref[0];
3473                 count = HAMMER2_SET_COUNT;
3474                 break;
3475         case HAMMER2_BREF_TYPE_FREEMAP:
3476                 KKASSERT(parent->data != NULL);
3477                 base = &parent->data->blkset.blockref[0];
3478                 count = HAMMER2_SET_COUNT;
3479                 break;
3480         default:
3481                 panic("hammer2_chain_create: unrecognized blockref type: %d",
3482                       parent->bref.type);
3483                 base = NULL;
3484                 count = 0;
3485                 break;
3486         }
3487
3488         /*
3489          * Make sure we've counted the brefs
3490          */
3491         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
3492                 hammer2_chain_countbrefs(parent, base, count);
3493
3494         KASSERT(parent->core.live_count >= 0 &&
3495                 parent->core.live_count <= count,
3496                 ("bad live_count %d/%d (%02x, %d)",
3497                         parent->core.live_count, count,
3498                         parent->bref.type, parent->bytes));
3499
3500         /*
3501          * If no free blockref could be found we must create an indirect
3502          * block and move a number of blockrefs into it.  With the parent
3503          * locked we can safely lock each child in order to delete+duplicate
3504          * it without causing a deadlock.
3505          *
3506          * This may return the new indirect block or the old parent depending
3507          * on where the key falls.  NULL is returned on error.
3508          */
3509         if (parent->core.live_count == count) {
3510                 hammer2_chain_t *nparent;
3511
3512                 KKASSERT((flags & HAMMER2_INSERT_SAMEPARENT) == 0);
3513
3514                 nparent = hammer2_chain_create_indirect(parent, key, keybits,
3515                                                         mtid, type, &error);
3516                 if (nparent == NULL) {
3517                         if (allocated)
3518                                 hammer2_chain_drop(chain);
3519                         chain = NULL;
3520                         goto done;
3521                 }
3522                 if (parent != nparent) {
3523                         hammer2_chain_unlock(parent);
3524                         hammer2_chain_drop(parent);
3525                         parent = *parentp = nparent;
3526                 }
3527                 goto again;
3528         }
3529
3530         /*
3531          * fall through if parent, or skip to here if no parent.
3532          */
3533 skip:
3534         if (chain->flags & HAMMER2_CHAIN_DELETED)
3535                 kprintf("Inserting deleted chain @%016jx\n",
3536                         chain->bref.key);
3537
3538         /*
3539          * Link the chain into its parent.
3540          */
3541         if (chain->parent != NULL)
3542                 panic("hammer2: hammer2_chain_create: chain already connected");
3543         KKASSERT(chain->parent == NULL);
3544         if (parent) {
3545                 KKASSERT(parent->core.live_count < count);
3546                 hammer2_chain_insert(parent, chain,
3547                                      HAMMER2_CHAIN_INSERT_SPIN |
3548                                      HAMMER2_CHAIN_INSERT_LIVE,
3549                                      0);
3550         }
3551
3552         if (allocated) {
3553                 /*
3554                  * Mark the newly created chain modified.  This will cause
3555                  * UPDATE to be set and process the INITIAL flag.
3556                  *
3557                  * Device buffers are not instantiated for DATA elements
3558                  * as these are handled by logical buffers.
3559                  *
3560                  * Indirect and freemap node indirect blocks are handled
3561                  * by hammer2_chain_create_indirect() and not by this
3562                  * function.
3563                  *
3564                  * Data for all other bref types is expected to be
3565                  * instantiated (INODE, LEAF).
3566                  */
3567                 switch(chain->bref.type) {
3568                 case HAMMER2_BREF_TYPE_DATA:
3569                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3570                 case HAMMER2_BREF_TYPE_DIRENT:
3571                 case HAMMER2_BREF_TYPE_INODE:
3572                         error = hammer2_chain_modify(chain, mtid, dedup_off,
3573                                                      HAMMER2_MODIFY_OPTDATA);
3574                         break;
3575                 default:
3576                         /*
3577                          * Remaining types are not supported by this function.
3578                          * In particular, INDIRECT and LEAF_NODE types are
3579                          * handled by create_indirect().
3580                          */
3581                         panic("hammer2_chain_create: bad type: %d",
3582                               chain->bref.type);
3583                         /* NOT REACHED */
3584                         break;
3585                 }
3586         } else {
3587                 /*
3588                  * When reconnecting a chain we must set UPDATE and
3589                  * setflush so the flush recognizes that it must update
3590                  * the bref in the parent.
3591                  */
3592                 if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0)
3593                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
3594         }
3595
3596         /*
3597          * We must setflush(parent) to ensure that it recurses through to
3598          * chain.  setflush(chain) might not work because ONFLUSH is possibly
3599          * already set in the chain (so it won't recurse up to set it in the
3600          * parent).
3601          */
3602         if (parent)
3603                 hammer2_chain_setflush(parent);
3604
3605 done:
3606         *chainp = chain;
3607
3608         return (error);
3609 }
3610
3611 /*
3612  * Move the chain from its old parent to a new parent.  The chain must have
3613  * already been deleted or already disconnected (or never associated) with
3614  * a parent.  The chain is reassociated with the new parent and the deleted
3615  * flag will be cleared (no longer deleted).  The chain's modification state
3616  * is not altered.
3617  *
3618  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (parent) TO THE INSERTION
3619  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
3620  * FULL.  This typically means that the caller is creating the chain after
3621  * doing a hammer2_chain_lookup().
3622  *
3623  * Neither (parent) or (chain) can be errored.
3624  *
3625  * If (parent) is non-NULL then the chain is inserted under the parent.
3626  *
3627  * If (parent) is NULL then the newly duplicated chain is not inserted
3628  * anywhere, similar to if it had just been chain_alloc()'d (suitable for
3629  * passing into hammer2_chain_create() after this function returns).
3630  *
3631  * WARNING! This function calls create which means it can insert indirect
3632  *          blocks.  This can cause other unrelated chains in the parent to
3633  *          be moved to a newly inserted indirect block in addition to the
3634  *          specific chain.
3635  */
3636 void
3637 hammer2_chain_rename(hammer2_chain_t **parentp, hammer2_chain_t *chain,
3638                      hammer2_tid_t mtid, int flags)
3639 {
3640         hammer2_blockref_t *bref;
3641         hammer2_dev_t *hmp;
3642         hammer2_chain_t *parent;
3643         size_t bytes;
3644
3645         /*
3646          * WARNING!  We should never resolve DATA to device buffers
3647          *           (XXX allow it if the caller did?), and since
3648          *           we currently do not have the logical buffer cache
3649          *           buffer in-hand to fix its cached physical offset
3650          *           we also force the modify code to not COW it. XXX
3651          *
3652          * NOTE!     We allow error'd chains to be renamed.  The bref itself
3653          *           is good and can be renamed.  The content, however, may
3654          *           be inaccessible.
3655          */
3656         hmp = chain->hmp;
3657         KKASSERT(chain->parent == NULL);
3658         /*KKASSERT(chain->error == 0); allow */
3659
3660         /*
3661          * Now create a duplicate of the chain structure, associating
3662          * it with the same core, making it the same size, pointing it
3663          * to the same bref (the same media block).
3664          *
3665          * NOTE: Handle special radix == 0 case (means 0 bytes).
3666          */
3667         bref = &chain->bref;
3668         bytes = (size_t)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
3669         if (bytes)
3670                 bytes = (hammer2_off_t)1 << bytes;
3671
3672         /*
3673          * If parent is not NULL the duplicated chain will be entered under
3674          * the parent and the UPDATE bit set to tell flush to update
3675          * the blockref.
3676          *
3677          * We must setflush(parent) to ensure that it recurses through to
3678          * chain.  setflush(chain) might not work because ONFLUSH is possibly
3679          * already set in the chain (so it won't recurse up to set it in the
3680          * parent).
3681          *
3682          * Having both chains locked is extremely important for atomicy.
3683          */
3684         if (parentp && (parent = *parentp) != NULL) {
3685                 KKASSERT(hammer2_mtx_owned(&parent->lock));
3686                 KKASSERT(parent->refs > 0);
3687                 KKASSERT(parent->error == 0);
3688
3689                 hammer2_chain_create(parentp, &chain, NULL, chain->pmp,
3690                                      HAMMER2_METH_DEFAULT,
3691                                      bref->key, bref->keybits, bref->type,
3692                                      chain->bytes, mtid, 0, flags);
3693                 KKASSERT(chain->flags & HAMMER2_CHAIN_UPDATE);
3694                 hammer2_chain_setflush(*parentp);
3695         }
3696 }
3697
3698 /*
3699  * This works in tandem with delete_obref() to install a blockref in
3700  * (typically) an indirect block that is associated with the chain being
3701  * moved to *parentp.
3702  *
3703  * The reason we need this function is that the caller needs to maintain
3704  * the blockref as it was, and not generate a new blockref for what might
3705  * be a modified chain.  Otherwise stuff will leak into the flush that
3706  * the flush code's FLUSH_INODE_STOP flag is unable to catch.
3707  *
3708  * It is EXTREMELY important that we properly set CHAIN_BMAPUPD and
3709  * CHAIN_UPDATE.  We must set BMAPUPD if the bref does not match, and
3710  * we must clear CHAIN_UPDATE (that was likely set by the chain_rename) if
3711  * it does.  Otherwise we can end up in a situation where H2 is unable to
3712  * clean up the in-memory chain topology.
3713  *
3714  * The reason for this is that flushes do not generally flush through
3715  * BREF_TYPE_INODE chains and depend on a hammer2_inode_t queued to syncq
3716  * or sideq to properly flush and dispose of the related inode chain's flags.
3717  * Situations where the inode is not actually modified by the frontend,
3718  * but where we have to move the related chains around as we insert or cleanup
3719  * indirect blocks, can leave us with a 'dirty' (non-disposable) in-memory
3720  * inode chain that does not have a hammer2_inode_t associated with it.
3721  */
3722 void
3723 hammer2_chain_rename_obref(hammer2_chain_t **parentp, hammer2_chain_t *chain,
3724                            hammer2_tid_t mtid, int flags,
3725                            hammer2_blockref_t *obref)
3726 {
3727         hammer2_chain_rename(parentp, chain, mtid, flags);
3728
3729         if (obref->type) {
3730                 hammer2_blockref_t *tbase;
3731                 int tcount;
3732
3733                 KKASSERT((chain->flags & HAMMER2_CHAIN_BMAPPED) == 0);
3734                 hammer2_chain_modify(*parentp, mtid, 0, 0);
3735                 tbase = hammer2_chain_base_and_count(*parentp, &tcount);
3736                 hammer2_base_insert(*parentp, tbase, tcount, chain, obref);
3737                 if (bcmp(obref, &chain->bref, sizeof(chain->bref))) {
3738                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPUPD |
3739                                                       HAMMER2_CHAIN_UPDATE);
3740                 } else {
3741                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
3742                 }
3743         }
3744 }
3745
3746 /*
3747  * Helper function for deleting chains.
3748  *
3749  * The chain is removed from the live view (the RBTREE) as well as the parent's
3750  * blockmap.  Both chain and its parent must be locked.
3751  *
3752  * parent may not be errored.  chain can be errored.
3753  */
3754 static int
3755 _hammer2_chain_delete_helper(hammer2_chain_t *parent, hammer2_chain_t *chain,
3756                              hammer2_tid_t mtid, int flags,
3757                              hammer2_blockref_t *obref)
3758 {
3759         hammer2_dev_t *hmp;
3760         int error = 0;
3761
3762         KKASSERT((chain->flags & (HAMMER2_CHAIN_DELETED |
3763                                   HAMMER2_CHAIN_FICTITIOUS)) == 0);
3764         KKASSERT(chain->parent == parent);
3765         hmp = chain->hmp;
3766
3767         if (chain->flags & HAMMER2_CHAIN_BMAPPED) {
3768                 /*
3769                  * Chain is blockmapped, so there must be a parent.
3770                  * Atomically remove the chain from the parent and remove
3771                  * the blockmap entry.  The parent must be set modified
3772                  * to remove the blockmap entry.
3773                  */
3774                 hammer2_blockref_t *base;
3775                 int count;
3776
3777                 KKASSERT(parent != NULL);
3778                 KKASSERT(parent->error == 0);
3779                 KKASSERT((parent->flags & HAMMER2_CHAIN_INITIAL) == 0);
3780                 error = hammer2_chain_modify(parent, mtid, 0, 0);
3781                 if (error)
3782                         goto done;
3783
3784                 /*
3785                  * Calculate blockmap pointer
3786                  */
3787                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
3788                 hammer2_spin_ex(&chain->core.spin);
3789                 hammer2_spin_ex(&parent->core.spin);
3790
3791                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3792                 atomic_add_int(&parent->core.live_count, -1);
3793                 ++parent->core.generation;
3794                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
3795                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
3796                 --parent->core.chain_count;
3797                 chain->parent = NULL;
3798
3799                 switch(parent->bref.type) {
3800                 case HAMMER2_BREF_TYPE_INODE:
3801                         /*
3802                          * Access the inode's block array.  However, there
3803                          * is no block array if the inode is flagged
3804                          * DIRECTDATA.
3805                          */
3806                         if (parent->data &&
3807                             (parent->data->ipdata.meta.op_flags &
3808                              HAMMER2_OPFLAG_DIRECTDATA) == 0) {
3809                                 base =
3810                                    &parent->data->ipdata.u.blockset.blockref[0];
3811                         } else {
3812                                 base = NULL;
3813                         }
3814                         count = HAMMER2_SET_COUNT;
3815                         break;
3816                 case HAMMER2_BREF_TYPE_INDIRECT:
3817                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3818                         if (parent->data)
3819                                 base = &parent->data->npdata[0];
3820                         else
3821                                 base = NULL;
3822                         count = parent->bytes / sizeof(hammer2_blockref_t);
3823                         break;
3824                 case HAMMER2_BREF_TYPE_VOLUME:
3825                         base = &parent->data->voldata.
3826                                         sroot_blockset.blockref[0];
3827                         count = HAMMER2_SET_COUNT;
3828                         break;
3829                 case HAMMER2_BREF_TYPE_FREEMAP:
3830                         base = &parent->data->blkset.blockref[0];
3831                         count = HAMMER2_SET_COUNT;
3832                         break;
3833                 default:
3834                         base = NULL;
3835                         count = 0;
3836                         panic("hammer2_flush_pass2: "
3837                               "unrecognized blockref type: %d",
3838                               parent->bref.type);
3839                 }
3840
3841                 /*
3842                  * delete blockmapped chain from its parent.
3843                  *
3844                  * The parent is not affected by any statistics in chain
3845                  * which are pending synchronization.  That is, there is
3846                  * nothing to undo in the parent since they have not yet
3847                  * been incorporated into the parent.
3848                  *
3849                  * The parent is affected by statistics stored in inodes.
3850                  * Those have already been synchronized, so they must be
3851                  * undone.  XXX split update possible w/delete in middle?
3852                  */
3853                 if (base) {
3854                         hammer2_base_delete(parent, base, count, chain, obref);
3855                 }
3856                 hammer2_spin_unex(&parent->core.spin);
3857                 hammer2_spin_unex(&chain->core.spin);
3858         } else if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
3859                 /*
3860                  * Chain is not blockmapped but a parent is present.
3861                  * Atomically remove the chain from the parent.  There is
3862                  * no blockmap entry to remove.
3863                  *
3864                  * Because chain was associated with a parent but not
3865                  * synchronized, the chain's *_count_up fields contain
3866                  * inode adjustment statistics which must be undone.
3867                  */
3868                 hammer2_spin_ex(&chain->core.spin);
3869                 hammer2_spin_ex(&parent->core.spin);
3870                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3871                 atomic_add_int(&parent->core.live_count, -1);
3872                 ++parent->core.generation;
3873                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
3874                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
3875                 --parent->core.chain_count;
3876                 chain->parent = NULL;
3877                 hammer2_spin_unex(&parent->core.spin);
3878                 hammer2_spin_unex(&chain->core.spin);
3879         } else {
3880                 /*
3881                  * Chain is not blockmapped and has no parent.  This
3882                  * is a degenerate case.
3883                  */
3884                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3885         }
3886 done:
3887         return error;
3888 }
3889
3890 /*
3891  * Create an indirect block that covers one or more of the elements in the
3892  * current parent.  Either returns the existing parent with no locking or
3893  * ref changes or returns the new indirect block locked and referenced
3894  * and leaving the original parent lock/ref intact as well.
3895  *
3896  * If an error occurs, NULL is returned and *errorp is set to the H2 error.
3897  *
3898  * The returned chain depends on where the specified key falls.
3899  *
3900  * The key/keybits for the indirect mode only needs to follow three rules:
3901  *
3902  * (1) That all elements underneath it fit within its key space and
3903  *
3904  * (2) That all elements outside it are outside its key space.
3905  *
3906  * (3) When creating the new indirect block any elements in the current
3907  *     parent that fit within the new indirect block's keyspace must be
3908  *     moved into the new indirect block.
3909  *
3910  * (4) The keyspace chosen for the inserted indirect block CAN cover a wider
3911  *     keyspace the the current parent, but lookup/iteration rules will
3912  *     ensure (and must ensure) that rule (2) for all parents leading up
3913  *     to the nearest inode or the root volume header is adhered to.  This
3914  *     is accomplished by always recursing through matching keyspaces in
3915  *     the hammer2_chain_lookup() and hammer2_chain_next() API.
3916  *
3917  * The current implementation calculates the current worst-case keyspace by
3918  * iterating the current parent and then divides it into two halves, choosing
3919  * whichever half has the most elements (not necessarily the half containing
3920  * the requested key).
3921  *
3922  * We can also opt to use the half with the least number of elements.  This
3923  * causes lower-numbered keys (aka logical file offsets) to recurse through
3924  * fewer indirect blocks and higher-numbered keys to recurse through more.
3925  * This also has the risk of not moving enough elements to the new indirect
3926  * block and being forced to create several indirect blocks before the element
3927  * can be inserted.
3928  *
3929  * Must be called with an exclusively locked parent.
3930  *
3931  * NOTE: *errorp set to HAMMER_ERROR_* flags
3932  */
3933 static int hammer2_chain_indkey_freemap(hammer2_chain_t *parent,
3934                                 hammer2_key_t *keyp, int keybits,
3935                                 hammer2_blockref_t *base, int count);
3936 static int hammer2_chain_indkey_file(hammer2_chain_t *parent,
3937                                 hammer2_key_t *keyp, int keybits,
3938                                 hammer2_blockref_t *base, int count,
3939                                 int ncount);
3940 static int hammer2_chain_indkey_dir(hammer2_chain_t *parent,
3941                                 hammer2_key_t *keyp, int keybits,
3942                                 hammer2_blockref_t *base, int count,
3943                                 int ncount);
3944 static
3945 hammer2_chain_t *
3946 hammer2_chain_create_indirect(hammer2_chain_t *parent,
3947                               hammer2_key_t create_key, int create_bits,
3948                               hammer2_tid_t mtid, int for_type, int *errorp)
3949 {
3950         hammer2_dev_t *hmp;
3951         hammer2_blockref_t *base;
3952         hammer2_blockref_t *bref;
3953         hammer2_blockref_t bcopy;
3954         hammer2_chain_t *chain;
3955         hammer2_chain_t *ichain;
3956         hammer2_chain_t dummy;
3957         hammer2_key_t key = create_key;
3958         hammer2_key_t key_beg;
3959         hammer2_key_t key_end;
3960         hammer2_key_t key_next;
3961         int keybits = create_bits;
3962         int count;
3963         int ncount;
3964         int nbytes;
3965         int loops;
3966         int error;
3967         int reason;
3968         int generation;
3969         int maxloops = 300000;
3970
3971         /*
3972          * Calculate the base blockref pointer or NULL if the chain
3973          * is known to be empty.  We need to calculate the array count
3974          * for RB lookups either way.
3975          */
3976         hmp = parent->hmp;
3977         KKASSERT(hammer2_mtx_owned(&parent->lock));
3978
3979         /*
3980          * Pre-modify the parent now to avoid having to deal with error
3981          * processing if we tried to later (in the middle of our loop).
3982          *
3983          * We are going to be moving bref's around, the indirect blocks
3984          * cannot be in an initial state.  Do not pass MODIFY_OPTDATA.
3985          */
3986         *errorp = hammer2_chain_modify(parent, mtid, 0, 0);
3987         if (*errorp) {
3988                 kprintf("hammer2_create_indirect: error %08x %s\n",
3989                         *errorp, hammer2_error_str(*errorp));
3990                 return NULL;
3991         }
3992         KKASSERT((parent->flags & HAMMER2_CHAIN_INITIAL) == 0);
3993
3994         /*hammer2_chain_modify(&parent, HAMMER2_MODIFY_OPTDATA);*/
3995         base = hammer2_chain_base_and_count(parent, &count);
3996
3997         /*
3998          * dummy used in later chain allocation (no longer used for lookups).
3999          */
4000         bzero(&dummy, sizeof(dummy));
4001
4002         /*
4003          * How big should our new indirect block be?  It has to be at least
4004          * as large as its parent for splits to work properly.
4005          *
4006          * The freemap uses a specific indirect block size.  The number of
4007          * levels are built dynamically and ultimately depend on the size
4008          * volume.  Because freemap blocks are taken from the reserved areas
4009          * of the volume our goal is efficiency (fewer levels) and not so
4010          * much to save disk space.
4011          *
4012          * The first indirect block level for a directory usually uses
4013          * HAMMER2_IND_BYTES_MIN (4KB = 32 directory entries).  Due to
4014          * the hash mechanism, this typically gives us a nominal
4015          * 32 * 4 entries with one level of indirection.
4016          *
4017          * We use HAMMER2_IND_BYTES_NOM (16KB = 128 blockrefs) for FILE
4018          * indirect blocks.  The initial 4 entries in the inode gives us
4019          * 256KB.  Up to 4 indirect blocks gives us 32MB.  Three levels
4020          * of indirection gives us 137GB, and so forth.  H2 can support
4021          * huge file sizes but they are not typical, so we try to stick
4022          * with compactness and do not use a larger indirect block size.
4023          *
4024          * We could use 64KB (PBUFSIZE), giving us 512 blockrefs, but
4025          * due to the way indirect blocks are created this usually winds
4026          * up being extremely inefficient for small files.  Even though
4027          * 16KB requires more levels of indirection for very large files,
4028          * the 16KB records can be ganged together into 64KB DIOs.
4029          */
4030         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
4031             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
4032                 nbytes = HAMMER2_FREEMAP_LEVELN_PSIZE;
4033         } else if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
4034                 if (parent->data->ipdata.meta.type ==
4035                     HAMMER2_OBJTYPE_DIRECTORY)
4036                         nbytes = HAMMER2_IND_BYTES_MIN; /* 4KB = 32 entries */
4037                 else
4038                         nbytes = HAMMER2_IND_BYTES_NOM; /* 16KB = ~8MB file */
4039
4040         } else {
4041                 nbytes = HAMMER2_IND_BYTES_NOM;
4042         }
4043         if (nbytes < count * sizeof(hammer2_blockref_t)) {
4044                 KKASSERT(for_type != HAMMER2_BREF_TYPE_FREEMAP_NODE &&
4045                          for_type != HAMMER2_BREF_TYPE_FREEMAP_LEAF);
4046                 nbytes = count * sizeof(hammer2_blockref_t);
4047         }
4048         ncount = nbytes / sizeof(hammer2_blockref_t);
4049
4050         /*
4051          * When creating an indirect block for a freemap node or leaf
4052          * the key/keybits must be fitted to static radix levels because
4053          * particular radix levels use particular reserved blocks in the
4054          * related zone.
4055          *
4056          * This routine calculates the key/radix of the indirect block
4057          * we need to create, and whether it is on the high-side or the
4058          * low-side.
4059          */
4060         switch(for_type) {
4061         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
4062         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
4063                 keybits = hammer2_chain_indkey_freemap(parent, &key, keybits,
4064                                                        base, count);
4065                 break;
4066         case HAMMER2_BREF_TYPE_DATA:
4067                 keybits = hammer2_chain_indkey_file(parent, &key, keybits,
4068                                                     base, count, ncount);
4069                 break;
4070         case HAMMER2_BREF_TYPE_DIRENT:
4071         case HAMMER2_BREF_TYPE_INODE:
4072                 keybits = hammer2_chain_indkey_dir(parent, &key, keybits,
4073                                                    base, count, ncount);
4074                 break;
4075         default:
4076                 panic("illegal indirect block for bref type %d", for_type);
4077                 break;
4078         }
4079
4080         /*
4081          * Normalize the key for the radix being represented, keeping the
4082          * high bits and throwing away the low bits.
4083          */
4084         key &= ~(((hammer2_key_t)1 << keybits) - 1);
4085
4086         /*
4087          * Ok, create our new indirect block
4088          */
4089         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
4090             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
4091                 dummy.bref.type = HAMMER2_BREF_TYPE_FREEMAP_NODE;
4092         } else {
4093                 dummy.bref.type = HAMMER2_BREF_TYPE_INDIRECT;
4094         }
4095         dummy.bref.key = key;
4096         dummy.bref.keybits = keybits;
4097         dummy.bref.data_off = hammer2_getradix(nbytes);
4098         dummy.bref.methods =
4099                 HAMMER2_ENC_CHECK(HAMMER2_DEC_CHECK(parent->bref.methods)) |
4100                 HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
4101
4102         ichain = hammer2_chain_alloc(hmp, parent->pmp, &dummy.bref);
4103         atomic_set_int(&ichain->flags, HAMMER2_CHAIN_INITIAL);
4104         hammer2_chain_lock(ichain, HAMMER2_RESOLVE_MAYBE);
4105         /* ichain has one ref at this point */
4106
4107         /*
4108          * We have to mark it modified to allocate its block, but use
4109          * OPTDATA to allow it to remain in the INITIAL state.  Otherwise
4110          * it won't be acted upon by the flush code.
4111          *
4112          * XXX remove OPTDATA, we need a fully initialized indirect block to
4113          * be able to move the original blockref.
4114          */
4115         *errorp = hammer2_chain_modify(ichain, mtid, 0, 0);
4116         if (*errorp) {
4117                 kprintf("hammer2_alloc_indirect: error %08x %s\n",
4118                         *errorp, hammer2_error_str(*errorp));
4119                 hammer2_chain_unlock(ichain);
4120                 hammer2_chain_drop(ichain);
4121                 return NULL;
4122         }
4123         KKASSERT((ichain->flags & HAMMER2_CHAIN_INITIAL) == 0);
4124
4125         /*
4126          * Iterate the original parent and move the matching brefs into
4127          * the new indirect block.
4128          *
4129          * XXX handle flushes.
4130          */
4131         key_beg = 0;
4132         key_end = HAMMER2_KEY_MAX;
4133         key_next = 0;   /* avoid gcc warnings */
4134         hammer2_spin_ex(&parent->core.spin);
4135         loops = 0;
4136         reason = 0;
4137
4138         for (;;) {
4139                 /*
4140                  * Parent may have been modified, relocating its block array.
4141                  * Reload the base pointer.
4142                  */
4143                 base = hammer2_chain_base_and_count(parent, &count);
4144
4145                 if (++loops > 100000) {
4146                     hammer2_spin_unex(&parent->core.spin);
4147                     panic("excessive loops r=%d p=%p base/count %p:%d %016jx\n",
4148                           reason, parent, base, count, key_next);
4149                 }
4150
4151                 /*
4152                  * NOTE: spinlock stays intact, returned chain (if not NULL)
4153                  *       is not referenced or locked which means that we
4154                  *       cannot safely check its flagged / deletion status
4155                  *       until we lock it.
4156                  */
4157                 chain = hammer2_combined_find(parent, base, count,
4158                                               &key_next,
4159                                               key_beg, key_end,
4160                                               &bref);
4161                 generation = parent->core.generation;
4162                 if (bref == NULL)
4163                         break;
4164                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4165
4166                 /*
4167                  * Skip keys that are not within the key/radix of the new
4168                  * indirect block.  They stay in the parent.
4169                  */
4170                 if ((~(((hammer2_key_t)1 << keybits) - 1) &
4171                     (key ^ bref->key)) != 0) {
4172                         goto next_key_spinlocked;
4173                 }
4174
4175                 /*
4176                  * Load the new indirect block by acquiring the related
4177                  * chains (potentially from media as it might not be
4178                  * in-memory).  Then move it to the new parent (ichain).
4179                  *
4180                  * chain is referenced but not locked.  We must lock the
4181                  * chain to obtain definitive state.
4182                  */
4183                 bcopy = *bref;
4184                 if (chain) {
4185                         /*
4186                          * Use chain already present in the RBTREE
4187                          */
4188                         hammer2_chain_ref(chain);
4189                         hammer2_spin_unex(&parent->core.spin);
4190                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_NEVER);
4191                 } else {
4192                         /*
4193                          * Get chain for blockref element.  _get returns NULL
4194                          * on insertion race.
4195                          */
4196                         hammer2_spin_unex(&parent->core.spin);
4197                         chain = hammer2_chain_get(parent, generation, &bcopy,
4198                                                   HAMMER2_RESOLVE_NEVER);
4199                         if (chain == NULL) {
4200                                 reason = 1;
4201                                 hammer2_spin_ex(&parent->core.spin);
4202                                 continue;
4203                         }
4204                 }
4205
4206                 /*
4207                  * This is always live so if the chain has been deleted
4208                  * we raced someone and we have to retry.
4209                  *
4210                  * NOTE: Lookups can race delete-duplicate because
4211                  *       delete-duplicate does not lock the parent's core
4212                  *       (they just use the spinlock on the core).
4213                  *
4214                  *       (note reversed logic for this one)
4215                  */
4216                 if (bcmp(&bcopy, &chain->bref, sizeof(bcopy)) ||
4217                     chain->parent != parent ||
4218                     (chain->flags & HAMMER2_CHAIN_DELETED)) {
4219                         hammer2_chain_unlock(chain);
4220                         hammer2_chain_drop(chain);
4221                         if (hammer2_debug & 0x0040) {
4222                                 kprintf("LOST PARENT RETRY "
4223                                 "RETRY (%p,%p)->%p %08x\n",
4224                                 parent, chain->parent, chain, chain->flags);
4225                         }
4226                         hammer2_spin_ex(&parent->core.spin);
4227                         continue;
4228                 }
4229
4230                 /*
4231                  * Shift the chain to the indirect block.
4232                  *
4233                  * WARNING! No reason for us to load chain data, pass NOSTATS
4234                  *          to prevent delete/insert from trying to access
4235                  *          inode stats (and thus asserting if there is no
4236                  *          chain->data loaded).
4237                  *
4238                  * WARNING! The (parent, chain) deletion may modify the parent
4239                  *          and invalidate the base pointer.
4240                  *
4241                  * WARNING! Parent must already be marked modified, so we
4242                  *          can assume that chain_delete always suceeds.
4243                  *
4244                  * WARNING! hammer2_chain_repchange() does not have to be
4245                  *          called (and doesn't work anyway because we are
4246                  *          only doing a partial shift).  A recursion that is
4247                  *          in-progress can continue at the current parent
4248                  *          and will be able to properly find its next key.
4249                  */
4250                 error = hammer2_chain_delete_obref(parent, chain, mtid, 0,
4251                                                    &bcopy);
4252                 KKASSERT(error == 0);
4253                 hammer2_chain_rename_obref(&ichain, chain, mtid, 0, &bcopy);
4254                 hammer2_chain_unlock(chain);
4255                 hammer2_chain_drop(chain);
4256                 KKASSERT(parent->refs > 0);
4257                 chain = NULL;
4258                 base = NULL;    /* safety */
4259                 hammer2_spin_ex(&parent->core.spin);
4260 next_key_spinlocked:
4261                 if (--maxloops == 0)
4262                         panic("hammer2_chain_create_indirect: maxloops");
4263                 reason = 4;
4264                 if (key_next == 0 || key_next > key_end)
4265                         break;
4266                 key_beg = key_next;
4267                 /* loop */
4268         }
4269         hammer2_spin_unex(&parent->core.spin);
4270
4271         /*
4272          * Insert the new indirect block into the parent now that we've
4273          * cleared out some entries in the parent.  We calculated a good
4274          * insertion index in the loop above (ichain->index).
4275          *
4276          * We don't have to set UPDATE here because we mark ichain
4277          * modified down below (so the normal modified -> flush -> set-moved
4278          * sequence applies).
4279          *
4280          * The insertion shouldn't race as this is a completely new block
4281          * and the parent is locked.
4282          */
4283         base = NULL;    /* safety, parent modify may change address */
4284         KKASSERT((ichain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
4285         KKASSERT(parent->core.live_count < count);
4286         hammer2_chain_insert(parent, ichain,
4287                              HAMMER2_CHAIN_INSERT_SPIN |
4288                              HAMMER2_CHAIN_INSERT_LIVE,
4289                              0);
4290
4291         /*
4292          * Make sure flushes propogate after our manual insertion.
4293          */
4294         hammer2_chain_setflush(ichain);
4295         hammer2_chain_setflush(parent);
4296
4297         /*
4298          * Figure out what to return.
4299          */
4300         if (~(((hammer2_key_t)1 << keybits) - 1) &
4301                    (create_key ^ key)) {
4302                 /*
4303                  * Key being created is outside the key range,
4304                  * return the original parent.
4305                  */
4306                 hammer2_chain_unlock(ichain);
4307                 hammer2_chain_drop(ichain);
4308         } else {
4309                 /*
4310                  * Otherwise its in the range, return the new parent.
4311                  * (leave both the new and old parent locked).
4312                  */
4313                 parent = ichain;
4314         }
4315
4316         return(parent);
4317 }
4318
4319 /*
4320  * Do maintenance on an indirect chain.  Both parent and chain are locked.
4321  *
4322  * Returns non-zero if (chain) is deleted, either due to being empty or
4323  * because its children were safely moved into the parent.
4324  */
4325 int
4326 hammer2_chain_indirect_maintenance(hammer2_chain_t *parent,
4327                                    hammer2_chain_t *chain)
4328 {
4329         hammer2_blockref_t *chain_base;
4330         hammer2_blockref_t *base;
4331         hammer2_blockref_t *bref;
4332         hammer2_blockref_t bcopy;
4333         hammer2_key_t key_next;
4334         hammer2_key_t key_beg;
4335         hammer2_key_t key_end;
4336         hammer2_chain_t *sub;
4337         int chain_count;
4338         int count;
4339         int error;
4340         int generation;
4341
4342         /*
4343          * Make sure we have an accurate live_count
4344          */
4345         if ((chain->flags & (HAMMER2_CHAIN_INITIAL |
4346                              HAMMER2_CHAIN_COUNTEDBREFS)) == 0) {
4347                 base = &chain->data->npdata[0];
4348                 count = chain->bytes / sizeof(hammer2_blockref_t);
4349                 hammer2_chain_countbrefs(chain, base, count);
4350         }
4351
4352         /*
4353          * If the indirect block is empty we can delete it.
4354          * (ignore deletion error)
4355          */
4356         if (chain->core.live_count == 0 && RB_EMPTY(&chain->core.rbtree)) {
4357                 hammer2_chain_delete(parent, chain,
4358                                      chain->bref.modify_tid,
4359                                      HAMMER2_DELETE_PERMANENT);
4360                 hammer2_chain_repchange(parent, chain);
4361                 return 1;
4362         }
4363
4364         base = hammer2_chain_base_and_count(parent, &count);
4365
4366         if ((parent->flags & (HAMMER2_CHAIN_INITIAL |
4367                              HAMMER2_CHAIN_COUNTEDBREFS)) == 0) {
4368                 hammer2_chain_countbrefs(parent, base, count);
4369         }
4370
4371         /*
4372          * Determine if we can collapse chain into parent, calculate
4373          * hysteresis for chain emptiness.
4374          */
4375         if (parent->core.live_count + chain->core.live_count - 1 > count)
4376                 return 0;
4377         chain_count = chain->bytes / sizeof(hammer2_blockref_t);
4378         if (chain->core.live_count > chain_count * 3 / 4)
4379                 return 0;
4380
4381         /*
4382          * Ok, theoretically we can collapse chain's contents into
4383          * parent.  chain is locked, but any in-memory children of chain
4384          * are not.  For this to work, we must be able to dispose of any
4385          * in-memory children of chain.
4386          *
4387          * For now require that there are no in-memory children of chain.
4388          *
4389          * WARNING! Both chain and parent must remain locked across this
4390          *          entire operation.
4391          */
4392
4393         /*
4394          * Parent must be marked modified.  Don't try to collapse it if we
4395          * can't mark it modified.  Once modified, destroy chain to make room
4396          * and to get rid of what will be a conflicting key (this is included
4397          * in the calculation above).  Finally, move the children of chain
4398          * into chain's parent.
4399          *
4400          * This order creates an accounting problem for bref.embed.stats
4401          * because we destroy chain before we remove its children.  Any
4402          * elements whos blockref is already synchronized will be counted
4403          * twice.  To deal with the problem we clean out chain's stats prior
4404          * to deleting it.
4405          */
4406         error = hammer2_chain_modify(parent, 0, 0, 0);
4407         if (error) {
4408                 krateprintf(&krate_h2me, "hammer2: indirect_maint: %s\n",
4409                             hammer2_error_str(error));
4410                 return 0;
4411         }
4412         error = hammer2_chain_modify(chain, chain->bref.modify_tid, 0, 0);
4413         if (error) {
4414                 krateprintf(&krate_h2me, "hammer2: indirect_maint: %s\n",
4415                             hammer2_error_str(error));
4416                 return 0;
4417         }
4418
4419         chain->bref.embed.stats.inode_count = 0;
4420         chain->bref.embed.stats.data_count = 0;
4421         error = hammer2_chain_delete(parent, chain,
4422                                      chain->bref.modify_tid,
4423                                      HAMMER2_DELETE_PERMANENT);
4424         KKASSERT(error == 0);
4425
4426         /*
4427          * The combined_find call requires core.spin to be held.  One would
4428          * think there wouldn't be any conflicts since we hold chain
4429          * exclusively locked, but the caching mechanism for 0-ref children
4430          * does not require a chain lock.
4431          */
4432         hammer2_spin_ex(&chain->core.spin);
4433
4434         key_next = 0;
4435         key_beg = 0;
4436         key_end = HAMMER2_KEY_MAX;
4437         for (;;) {
4438                 chain_base = &chain->data->npdata[0];
4439                 chain_count = chain->bytes / sizeof(hammer2_blockref_t);
4440                 sub = hammer2_combined_find(chain, chain_base, chain_count,
4441                                             &key_next,
4442                                             key_beg, key_end,
4443                                             &bref);
4444                 generation = chain->core.generation;
4445                 if (bref == NULL)
4446                         break;
4447                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4448
4449                 bcopy = *bref;
4450                 if (sub) {
4451                         hammer2_chain_ref(sub);
4452                         hammer2_spin_unex(&chain->core.spin);
4453                         hammer2_chain_lock(sub, HAMMER2_RESOLVE_NEVER);
4454                 } else {
4455                         hammer2_spin_unex(&chain->core.spin);
4456                         sub = hammer2_chain_get(chain, generation, &bcopy,
4457                                                 HAMMER2_RESOLVE_NEVER);
4458                         if (sub == NULL) {
4459                                 hammer2_spin_ex(&chain->core.spin);
4460                                 continue;
4461                         }
4462                 }
4463                 if (bcmp(&bcopy, &sub->bref, sizeof(bcopy)) ||
4464                     sub->parent != chain ||
4465                     (sub->flags & HAMMER2_CHAIN_DELETED)) {
4466                         hammer2_chain_unlock(sub);
4467                         hammer2_chain_drop(sub);
4468                         hammer2_spin_ex(&chain->core.spin);
4469                         sub = NULL;     /* safety */
4470                         continue;
4471                 }
4472                 error = hammer2_chain_delete_obref(chain, sub,
4473                                                    sub->bref.modify_tid, 0,
4474                                                    &bcopy);
4475                 KKASSERT(error == 0);
4476                 hammer2_chain_rename_obref(&parent, sub,
4477                                      sub->bref.modify_tid,
4478                                      HAMMER2_INSERT_SAMEPARENT, &bcopy);
4479                 hammer2_chain_unlock(sub);
4480                 hammer2_chain_drop(sub);
4481                 hammer2_spin_ex(&chain->core.spin);
4482
4483                 if (key_next == 0)
4484                         break;
4485                 key_beg = key_next;
4486         }
4487         hammer2_spin_unex(&chain->core.spin);
4488
4489         hammer2_chain_repchange(parent, chain);
4490
4491         return 1;
4492 }
4493
4494 /*
4495  * Freemap indirect blocks
4496  *
4497  * Calculate the keybits and highside/lowside of the freemap node the
4498  * caller is creating.
4499  *
4500  * This routine will specify the next higher-level freemap key/radix
4501  * representing the lowest-ordered set.  By doing so, eventually all
4502  * low-ordered sets will be moved one level down.
4503  *
4504  * We have to be careful here because the freemap reserves a limited
4505  * number of blocks for a limited number of levels.  So we can't just
4506  * push indiscriminately.
4507  */
4508 int
4509 hammer2_chain_indkey_freemap(hammer2_chain_t *parent, hammer2_key_t *keyp,
4510                              int keybits, hammer2_blockref_t *base, int count)
4511 {
4512         hammer2_chain_t *chain;
4513         hammer2_blockref_t *bref;
4514         hammer2_key_t key;
4515         hammer2_key_t key_beg;
4516         hammer2_key_t key_end;
4517         hammer2_key_t key_next;
4518         int locount;
4519         int hicount;
4520         int maxloops = 300000;
4521
4522         key = *keyp;
4523         locount = 0;
4524         hicount = 0;
4525         keybits = 64;
4526
4527         /*
4528          * Calculate the range of keys in the array being careful to skip
4529          * slots which are overridden with a deletion.
4530          */
4531         key_beg = 0;
4532         key_end = HAMMER2_KEY_MAX;
4533         hammer2_spin_ex(&parent->core.spin);
4534
4535         for (;;) {
4536                 if (--maxloops == 0) {
4537                         panic("indkey_freemap shit %p %p:%d\n",
4538                               parent, base, count);
4539                 }
4540                 chain = hammer2_combined_find(parent, base, count,
4541                                               &key_next,
4542                                               key_beg, key_end,
4543                                               &bref);
4544
4545                 /*
4546                  * Exhausted search
4547                  */
4548                 if (bref == NULL)
4549                         break;
4550
4551                 /*
4552                  * Skip deleted chains.
4553                  */
4554                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4555                         if (key_next == 0 || key_next > key_end)
4556                                 break;
4557                         key_beg = key_next;
4558                         continue;
4559                 }
4560
4561                 /*
4562                  * Use the full live (not deleted) element for the scan
4563                  * iteration.  HAMMER2 does not allow partial replacements.
4564                  *
4565                  * XXX should be built into hammer2_combined_find().
4566                  */
4567                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4568
4569                 if (keybits > bref->keybits) {
4570                         key = bref->key;
4571                         keybits = bref->keybits;
4572                 } else if (keybits == bref->keybits && bref->key < key) {
4573                         key = bref->key;
4574                 }
4575                 if (key_next == 0)
4576                         break;
4577                 key_beg = key_next;
4578         }
4579         hammer2_spin_unex(&parent->core.spin);
4580
4581         /*
4582          * Return the keybits for a higher-level FREEMAP_NODE covering
4583          * this node.
4584          */
4585         switch(keybits) {
4586         case HAMMER2_FREEMAP_LEVEL0_RADIX:
4587                 keybits = HAMMER2_FREEMAP_LEVEL1_RADIX;
4588                 break;
4589         case HAMMER2_FREEMAP_LEVEL1_RADIX:
4590                 keybits = HAMMER2_FREEMAP_LEVEL2_RADIX;
4591                 break;
4592         case HAMMER2_FREEMAP_LEVEL2_RADIX:
4593                 keybits = HAMMER2_FREEMAP_LEVEL3_RADIX;
4594                 break;
4595         case HAMMER2_FREEMAP_LEVEL3_RADIX:
4596                 keybits = HAMMER2_FREEMAP_LEVEL4_RADIX;
4597                 break;
4598         case HAMMER2_FREEMAP_LEVEL4_RADIX:
4599                 keybits = HAMMER2_FREEMAP_LEVEL5_RADIX;
4600                 break;
4601         case HAMMER2_FREEMAP_LEVEL5_RADIX:
4602                 panic("hammer2_chain_indkey_freemap: level too high");
4603                 break;
4604         default:
4605                 panic("hammer2_chain_indkey_freemap: bad radix");
4606                 break;
4607         }
4608         *keyp = key;
4609
4610         return (keybits);
4611 }
4612
4613 /*
4614  * File indirect blocks
4615  *
4616  * Calculate the key/keybits for the indirect block to create by scanning
4617  * existing keys.  The key being created is also passed in *keyp and can be
4618  * inside or outside the indirect block.  Regardless, the indirect block
4619  * must hold at least two keys in order to guarantee sufficient space.
4620  *
4621  * We use a modified version of the freemap's fixed radix tree, but taylored
4622  * for file data.  Basically we configure an indirect block encompassing the
4623  * smallest key.
4624  */
4625 static int
4626 hammer2_chain_indkey_file(hammer2_chain_t *parent, hammer2_key_t *keyp,
4627                             int keybits, hammer2_blockref_t *base, int count,
4628                             int ncount)
4629 {
4630         hammer2_chain_t *chain;
4631         hammer2_blockref_t *bref;
4632         hammer2_key_t key;
4633         hammer2_key_t key_beg;
4634         hammer2_key_t key_end;
4635         hammer2_key_t key_next;
4636         int nradix;
4637         int locount;
4638         int hicount;
4639         int maxloops = 300000;
4640
4641         key = *keyp;
4642         locount = 0;
4643         hicount = 0;
4644         keybits = 64;
4645
4646         /*
4647          * Calculate the range of keys in the array being careful to skip
4648          * slots which are overridden with a deletion.
4649          *
4650          * Locate the smallest key.
4651          */
4652         key_beg = 0;
4653         key_end = HAMMER2_KEY_MAX;
4654         hammer2_spin_ex(&parent->core.spin);
4655
4656         for (;;) {
4657                 if (--maxloops == 0) {
4658                         panic("indkey_freemap shit %p %p:%d\n",
4659                               parent, base, count);
4660                 }
4661                 chain = hammer2_combined_find(parent, base, count,
4662                                               &key_next,
4663                                               key_beg, key_end,
4664                                               &bref);
4665
4666                 /*
4667                  * Exhausted search
4668                  */
4669                 if (bref == NULL)
4670                         break;
4671
4672                 /*
4673                  * Skip deleted chains.
4674                  */
4675                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4676                         if (key_next == 0 || key_next > key_end)
4677                                 break;
4678                         key_beg = key_next;
4679                         continue;
4680                 }
4681
4682                 /*
4683                  * Use the full live (not deleted) element for the scan
4684                  * iteration.  HAMMER2 does not allow partial replacements.
4685                  *
4686                  * XXX should be built into hammer2_combined_find().
4687                  */
4688                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4689
4690                 if (keybits > bref->keybits) {
4691                         key = bref->key;
4692                         keybits = bref->keybits;
4693                 } else if (keybits == bref->keybits && bref->key < key) {
4694                         key = bref->key;
4695                 }
4696                 if (key_next == 0)
4697                         break;
4698                 key_beg = key_next;
4699         }
4700         hammer2_spin_unex(&parent->core.spin);
4701
4702         /*
4703          * Calculate the static keybits for a higher-level indirect block
4704          * that contains the key.
4705          */
4706         *keyp = key;
4707
4708         switch(ncount) {
4709         case HAMMER2_IND_BYTES_MIN / sizeof(hammer2_blockref_t):
4710                 nradix = HAMMER2_IND_RADIX_MIN - HAMMER2_BLOCKREF_RADIX;
4711                 break;
4712         case HAMMER2_IND_BYTES_NOM / sizeof(hammer2_blockref_t):
4713                 nradix = HAMMER2_IND_RADIX_NOM - HAMMER2_BLOCKREF_RADIX;
4714                 break;
4715         case HAMMER2_IND_BYTES_MAX / sizeof(hammer2_blockref_t):
4716                 nradix = HAMMER2_IND_RADIX_MAX - HAMMER2_BLOCKREF_RADIX;
4717                 break;
4718         default:
4719                 panic("bad ncount %d\n", ncount);
4720                 nradix = 0;
4721                 break;
4722         }
4723
4724         /*
4725          * The largest radix that can be returned for an indirect block is
4726          * 63 bits.  (The largest practical indirect block radix is actually
4727          * 62 bits because the top-level inode or volume root contains four
4728          * entries, but allow 63 to be returned).
4729          */
4730         if (nradix >= 64)
4731                 nradix = 63;
4732
4733         return keybits + nradix;
4734 }
4735
4736 #if 1
4737
4738 /*
4739  * Directory indirect blocks.
4740  *
4741  * Covers both the inode index (directory of inodes), and directory contents
4742  * (filenames hardlinked to inodes).
4743  *
4744  * Because directory keys are hashed we generally try to cut the space in
4745  * half.  We accomodate the inode index (which tends to have linearly
4746  * increasing inode numbers) by ensuring that the keyspace is at least large
4747  * enough to fill up the indirect block being created.
4748  */
4749 static int
4750 hammer2_chain_indkey_dir(hammer2_chain_t *parent, hammer2_key_t *keyp,
4751                          int keybits, hammer2_blockref_t *base, int count,
4752                          int ncount)
4753 {
4754         hammer2_blockref_t *bref;
4755         hammer2_chain_t *chain;
4756         hammer2_key_t key_beg;
4757         hammer2_key_t key_end;
4758         hammer2_key_t key_next;
4759         hammer2_key_t key;
4760         int nkeybits;
4761         int locount;
4762         int hicount;
4763         int maxloops = 300000;
4764
4765         /*
4766          * NOTE: We can't take a shortcut here anymore for inodes because
4767          *       the root directory can contain a mix of inodes and directory
4768          *       entries (we used to just return 63 if parent->bref.type was
4769          *       HAMMER2_BREF_TYPE_INODE.
4770          */
4771         key = *keyp;
4772         locount = 0;
4773         hicount = 0;
4774
4775         /*
4776          * Calculate the range of keys in the array being careful to skip
4777          * slots which are overridden with a deletion.
4778          */
4779         key_beg = 0;
4780         key_end = HAMMER2_KEY_MAX;
4781         hammer2_spin_ex(&parent->core.spin);
4782
4783         for (;;) {
4784                 if (--maxloops == 0) {
4785                         panic("indkey_freemap shit %p %p:%d\n",
4786                               parent, base, count);
4787                 }
4788                 chain = hammer2_combined_find(parent, base, count,
4789                                               &key_next,
4790                                               key_beg, key_end,
4791                                               &bref);
4792
4793                 /*
4794                  * Exhausted search
4795                  */
4796                 if (bref == NULL)
4797                         break;
4798
4799                 /*
4800                  * Deleted object
4801                  */
4802                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4803                         if (key_next == 0 || key_next > key_end)
4804                                 break;
4805                         key_beg = key_next;
4806                         continue;
4807                 }
4808
4809                 /*
4810                  * Use the full live (not deleted) element for the scan
4811                  * iteration.  HAMMER2 does not allow partial replacements.
4812                  *
4813                  * XXX should be built into hammer2_combined_find().
4814                  */
4815                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4816
4817                 /*
4818                  * Expand our calculated key range (key, keybits) to fit
4819                  * the scanned key.  nkeybits represents the full range
4820                  * that we will later cut in half (two halves @ nkeybits - 1).
4821                  */
4822                 nkeybits = keybits;
4823                 if (nkeybits < bref->keybits) {
4824                         if (bref->keybits > 64) {
4825                                 kprintf("bad bref chain %p bref %p\n",
4826                                         chain, bref);
4827                                 Debugger("fubar");
4828                         }
4829                         nkeybits = bref->keybits;
4830                 }
4831                 while (nkeybits < 64 &&
4832                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
4833                         (key ^ bref->key)) != 0) {
4834                         ++nkeybits;
4835                 }
4836
4837                 /*
4838                  * If the new key range is larger we have to determine
4839                  * which side of the new key range the existing keys fall
4840                  * under by checking the high bit, then collapsing the
4841                  * locount into the hicount or vise-versa.
4842                  */
4843                 if (keybits != nkeybits) {
4844                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
4845                                 hicount += locount;
4846                                 locount = 0;
4847                         } else {
4848                                 locount += hicount;
4849                                 hicount = 0;
4850                         }
4851                         keybits = nkeybits;
4852                 }
4853
4854                 /*
4855                  * The newly scanned key will be in the lower half or the
4856                  * upper half of the (new) key range.
4857                  */
4858                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
4859                         ++hicount;
4860                 else
4861                         ++locount;
4862
4863                 if (key_next == 0)
4864                         break;
4865                 key_beg = key_next;
4866         }
4867         hammer2_spin_unex(&parent->core.spin);
4868         bref = NULL;    /* now invalid (safety) */
4869
4870         /*
4871          * Adjust keybits to represent half of the full range calculated
4872          * above (radix 63 max) for our new indirect block.
4873          */
4874         --keybits;
4875
4876         /*
4877          * Expand keybits to hold at least ncount elements.  ncount will be
4878          * a power of 2.  This is to try to completely fill leaf nodes (at
4879          * least for keys which are not hashes).
4880          *
4881          * We aren't counting 'in' or 'out', we are counting 'high side'
4882          * and 'low side' based on the bit at (1LL << keybits).  We want
4883          * everything to be inside in these cases so shift it all to
4884          * the low or high side depending on the new high bit.
4885          */
4886         while (((hammer2_key_t)1 << keybits) < ncount) {
4887                 ++keybits;
4888                 if (key & ((hammer2_key_t)1 << keybits)) {
4889                         hicount += locount;
4890                         locount = 0;
4891                 } else {
4892                         locount += hicount;
4893                         hicount = 0;
4894                 }
4895         }
4896
4897         if (hicount > locount)
4898                 key |= (hammer2_key_t)1 << keybits;
4899         else
4900                 key &= ~(hammer2_key_t)1 << keybits;
4901
4902         *keyp = key;
4903
4904         return (keybits);
4905 }
4906
4907 #else
4908
4909 /*
4910  * Directory indirect blocks.
4911  *
4912  * Covers both the inode index (directory of inodes), and directory contents
4913  * (filenames hardlinked to inodes).
4914  *
4915  * Because directory keys are hashed we generally try to cut the space in
4916  * half.  We accomodate the inode index (which tends to have linearly
4917  * increasing inode numbers) by ensuring that the keyspace is at least large
4918  * enough to fill up the indirect block being created.
4919  */
4920 static int
4921 hammer2_chain_indkey_dir(hammer2_chain_t *parent, hammer2_key_t *keyp,
4922                          int keybits, hammer2_blockref_t *base, int count,
4923                          int ncount)
4924 {
4925         hammer2_blockref_t *bref;
4926         hammer2_chain_t *chain;
4927         hammer2_key_t key_beg;
4928         hammer2_key_t key_end;
4929         hammer2_key_t key_next;
4930         hammer2_key_t key;
4931         int nkeybits;
4932         int locount;
4933         int hicount;
4934         int maxloops = 300000;
4935
4936         /*
4937          * Shortcut if the parent is the inode.  In this situation the
4938          * parent has 4+1 directory entries and we are creating an indirect
4939          * block capable of holding many more.
4940          */
4941         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
4942                 return 63;
4943         }
4944
4945         key = *keyp;
4946         locount = 0;
4947         hicount = 0;
4948
4949         /*
4950          * Calculate the range of keys in the array being careful to skip
4951          * slots which are overridden with a deletion.
4952          */
4953         key_beg = 0;
4954         key_end = HAMMER2_KEY_MAX;
4955         hammer2_spin_ex(&parent->core.spin);
4956
4957         for (;;) {
4958                 if (--maxloops == 0) {
4959                         panic("indkey_freemap shit %p %p:%d\n",
4960                               parent, base, count);
4961                 }
4962                 chain = hammer2_combined_find(parent, base, count,
4963                                               &key_next,
4964                                               key_beg, key_end,
4965                                               &bref);
4966
4967                 /*
4968                  * Exhausted search
4969                  */
4970                 if (bref == NULL)
4971                         break;
4972
4973                 /*
4974                  * Deleted object
4975                  */
4976                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4977                         if (key_next == 0 || key_next > key_end)
4978                                 break;
4979                         key_beg = key_next;
4980                         continue;
4981                 }
4982
4983                 /*
4984                  * Use the full live (not deleted) element for the scan
4985                  * iteration.  HAMMER2 does not allow partial replacements.
4986                  *
4987                  * XXX should be built into hammer2_combined_find().
4988                  */
4989                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4990
4991                 /*
4992                  * Expand our calculated key range (key, keybits) to fit
4993                  * the scanned key.  nkeybits represents the full range
4994                  * that we will later cut in half (two halves @ nkeybits - 1).
4995                  */
4996                 nkeybits = keybits;
4997                 if (nkeybits < bref->keybits) {
4998                         if (bref->keybits > 64) {
4999                                 kprintf("bad bref chain %p bref %p\n",
5000                                         chain, bref);
5001                                 Debugger("fubar");
5002                         }
5003                         nkeybits = bref->keybits;
5004                 }
5005                 while (nkeybits < 64 &&
5006                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
5007                         (key ^ bref->key)) != 0) {
5008                         ++nkeybits;
5009                 }
5010
5011                 /*
5012                  * If the new key range is larger we have to determine
5013                  * which side of the new key range the existing keys fall
5014                  * under by checking the high bit, then collapsing the
5015                  * locount into the hicount or vise-versa.
5016                  */
5017                 if (keybits != nkeybits) {
5018                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
5019                                 hicount += locount;
5020                                 locount = 0;
5021                         } else {
5022                                 locount += hicount;
5023                                 hicount = 0;
5024                         }
5025                         keybits = nkeybits;
5026                 }
5027
5028                 /*
5029                  * The newly scanned key will be in the lower half or the
5030                  * upper half of the (new) key range.
5031                  */
5032                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
5033                         ++hicount;
5034                 else
5035                         ++locount;
5036
5037                 if (key_next == 0)
5038                         break;
5039                 key_beg = key_next;
5040         }
5041         hammer2_spin_unex(&parent->core.spin);
5042         bref = NULL;    /* now invalid (safety) */
5043
5044         /*
5045          * Adjust keybits to represent half of the full range calculated
5046          * above (radix 63 max) for our new indirect block.
5047          */
5048         --keybits;
5049
5050         /*
5051          * Expand keybits to hold at least ncount elements.  ncount will be
5052          * a power of 2.  This is to try to completely fill leaf nodes (at
5053          * least for keys which are not hashes).
5054          *
5055          * We aren't counting 'in' or 'out', we are counting 'high side'
5056          * and 'low side' based on the bit at (1LL << keybits).  We want
5057          * everything to be inside in these cases so shift it all to
5058          * the low or high side depending on the new high bit.
5059          */
5060         while (((hammer2_key_t)1 << keybits) < ncount) {
5061                 ++keybits;
5062                 if (key & ((hammer2_key_t)1 << keybits)) {
5063                         hicount += locount;
5064                         locount = 0;
5065                 } else {
5066                         locount += hicount;
5067                         hicount = 0;
5068                 }
5069         }
5070
5071         if (hicount > locount)
5072                 key |= (hammer2_key_t)1 << keybits;
5073         else
5074                 key &= ~(hammer2_key_t)1 << keybits;
5075
5076         *keyp = key;
5077
5078         return (keybits);
5079 }
5080
5081 #endif
5082
5083 /*
5084  * Sets CHAIN_DELETED and remove the chain's blockref from the parent if
5085  * it exists.
5086  *
5087  * Both parent and chain must be locked exclusively.
5088  *
5089  * This function will modify the parent if the blockref requires removal
5090  * from the parent's block table.
5091  *
5092  * This function is NOT recursive.  Any entity already pushed into the
5093  * chain (such as an inode) may still need visibility into its contents,
5094  * as well as the ability to read and modify the contents.  For example,
5095  * for an unlinked file which is still open.
5096  *
5097  * Also note that the flusher is responsible for cleaning up empty
5098  * indirect blocks.
5099  */
5100 int
5101 hammer2_chain_delete(hammer2_chain_t *parent, hammer2_chain_t *chain,
5102                      hammer2_tid_t mtid, int flags)
5103 {
5104         int error = 0;
5105
5106         KKASSERT(hammer2_mtx_owned(&chain->lock));
5107
5108         /*
5109          * Nothing to do if already marked.
5110          *
5111          * We need the spinlock on the core whos RBTREE contains chain
5112          * to protect against races.
5113          */
5114         if ((chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
5115                 KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0 &&
5116                          chain->parent == parent);
5117                 error = _hammer2_chain_delete_helper(parent, chain,
5118                                                      mtid, flags, NULL);
5119         }
5120
5121         /*
5122          * Permanent deletions mark the chain as destroyed.
5123          *
5124          * NOTE: We do not setflush the chain unless the deletion is
5125          *       permanent, since the deletion of a chain does not actually
5126          *       require it to be flushed.
5127          */
5128         if (error == 0) {
5129                 if (flags & HAMMER2_DELETE_PERMANENT) {
5130                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
5131                         hammer2_chain_setflush(chain);
5132                 }
5133         }
5134
5135         return error;
5136 }
5137
5138 static int
5139 hammer2_chain_delete_obref(hammer2_chain_t *parent, hammer2_chain_t *chain,
5140                      hammer2_tid_t mtid, int flags,
5141                      hammer2_blockref_t *obref)
5142 {
5143         int error = 0;
5144
5145         KKASSERT(hammer2_mtx_owned(&chain->lock));
5146
5147         /*
5148          * Nothing to do if already marked.
5149          *
5150          * We need the spinlock on the core whos RBTREE contains chain
5151          * to protect against races.
5152          */
5153         obref->type = HAMMER2_BREF_TYPE_EMPTY;
5154         if ((chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
5155                 KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0 &&
5156                          chain->parent == parent);
5157                 error = _hammer2_chain_delete_helper(parent, chain,
5158                                                      mtid, flags, obref);
5159         }
5160
5161         /*
5162          * Permanent deletions mark the chain as destroyed.
5163          *
5164          * NOTE: We do not setflush the chain unless the deletion is
5165          *       permanent, since the deletion of a chain does not actually
5166          *       require it to be flushed.
5167          */
5168         if (error == 0) {
5169                 if (flags & HAMMER2_DELETE_PERMANENT) {
5170                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
5171                         hammer2_chain_setflush(chain);
5172                 }
5173         }
5174
5175         return error;
5176 }
5177
5178 /*
5179  * Returns the index of the nearest element in the blockref array >= elm.
5180  * Returns (count) if no element could be found.
5181  *
5182  * Sets *key_nextp to the next key for loop purposes but does not modify
5183  * it if the next key would be higher than the current value of *key_nextp.
5184  * Note that *key_nexp can overflow to 0, which should be tested by the
5185  * caller.
5186  *
5187  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
5188  *           held through the operation.
5189  */
5190 static int
5191 hammer2_base_find(hammer2_chain_t *parent,
5192                   hammer2_blockref_t *base, int count,
5193                   hammer2_key_t *key_nextp,
5194                   hammer2_key_t key_beg, hammer2_key_t key_end)
5195 {
5196         hammer2_blockref_t *scan;
5197         hammer2_key_t scan_end;
5198         int i;
5199         int limit;
5200
5201         /*
5202          * Require the live chain's already have their core's counted
5203          * so we can optimize operations.
5204          */
5205         KKASSERT(parent->flags & HAMMER2_CHAIN_COUNTEDBREFS);
5206
5207         /*
5208          * Degenerate case
5209          */
5210         if (count == 0 || base == NULL)
5211                 return(count);
5212
5213         /*
5214          * Sequential optimization using parent->cache_index.  This is
5215          * the most likely scenario.
5216          *
5217          * We can avoid trailing empty entries on live chains, otherwise
5218          * we might have to check the whole block array.
5219          */
5220         i = parent->cache_index;        /* SMP RACE OK */
5221         cpu_ccfence();
5222         limit = parent->core.live_zero;
5223         if (i >= limit)
5224                 i = limit - 1;
5225         if (i < 0)
5226                 i = 0;
5227         KKASSERT(i < count);
5228
5229         /*
5230          * Search backwards
5231          */
5232         scan = &base[i];
5233         while (i > 0 && (scan->type == HAMMER2_BREF_TYPE_EMPTY ||
5234             scan->key > key_beg)) {
5235                 --scan;
5236                 --i;
5237         }
5238         parent->cache_index = i;
5239
5240         /*
5241          * Search forwards, stop when we find a scan element which
5242          * encloses the key or until we know that there are no further
5243          * elements.
5244          */
5245         while (i < count) {
5246                 if (scan->type != HAMMER2_BREF_TYPE_EMPTY) {
5247                         scan_end = scan->key +
5248                                    ((hammer2_key_t)1 << scan->keybits) - 1;
5249                         if (scan->key > key_beg || scan_end >= key_beg)
5250                                 break;
5251                 }
5252                 if (i >= limit)
5253                         return (count);
5254                 ++scan;
5255                 ++i;
5256         }
5257         if (i != count) {
5258                 parent->cache_index = i;
5259                 if (i >= limit) {
5260                         i = count;
5261                 } else {
5262                         scan_end = scan->key +
5263                                    ((hammer2_key_t)1 << scan->keybits);
5264                         if (scan_end && (*key_nextp > scan_end ||
5265                                          *key_nextp == 0)) {
5266                                 *key_nextp = scan_end;
5267                         }
5268                 }
5269         }
5270         return (i);
5271 }
5272
5273 /*
5274  * Do a combined search and return the next match either from the blockref
5275  * array or from the in-memory chain.  Sets *bresp to the returned bref in
5276  * both cases, or sets it to NULL if the search exhausted.  Only returns
5277  * a non-NULL chain if the search matched from the in-memory chain.
5278  *
5279  * When no in-memory chain has been found and a non-NULL bref is returned
5280  * in *bresp.
5281  *
5282  *
5283  * The returned chain is not locked or referenced.  Use the returned bref
5284  * to determine if the search exhausted or not.  Iterate if the base find
5285  * is chosen but matches a deleted chain.
5286  *
5287  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
5288  *           held through the operation.
5289  */
5290 hammer2_chain_t *
5291 hammer2_combined_find(hammer2_chain_t *parent,
5292                       hammer2_blockref_t *base, int count,
5293                       hammer2_key_t *key_nextp,
5294                       hammer2_key_t key_beg, hammer2_key_t key_end,
5295                       hammer2_blockref_t **bresp)
5296 {
5297         hammer2_blockref_t *bref;
5298         hammer2_chain_t *chain;
5299         int i;
5300
5301         /*
5302          * Lookup in block array and in rbtree.
5303          */
5304         *key_nextp = key_end + 1;
5305         i = hammer2_base_find(parent, base, count, key_nextp,
5306                               key_beg, key_end);
5307         chain = hammer2_chain_find(parent, key_nextp, key_beg, key_end);
5308
5309         /*
5310          * Neither matched
5311          */
5312         if (i == count && chain == NULL) {
5313                 *bresp = NULL;
5314                 return(NULL);
5315         }
5316
5317         /*
5318          * Only chain matched.
5319          */
5320         if (i == count) {
5321                 bref = &chain->bref;
5322                 goto found;
5323         }
5324
5325         /*
5326          * Only blockref matched.
5327          */
5328         if (chain == NULL) {
5329                 bref = &base[i];
5330                 goto found;
5331         }
5332
5333         /*
5334          * Both in-memory and blockref matched, select the nearer element.
5335          *
5336          * If both are flush with the left-hand side or both are the
5337          * same distance away, select the chain.  In this situation the
5338          * chain must have been loaded from the matching blockmap.
5339          */
5340         if ((chain->bref.key <= key_beg && base[i].key <= key_beg) ||
5341             chain->bref.key == base[i].key) {
5342                 KKASSERT(chain->bref.key == base[i].key);
5343                 bref = &chain->bref;
5344                 goto found;
5345         }
5346
5347         /*
5348          * Select the nearer key
5349          */
5350         if (chain->bref.key < base[i].key) {
5351                 bref = &chain->bref;
5352         } else {
5353                 bref = &base[i];
5354                 chain = NULL;
5355         }
5356
5357         /*
5358          * If the bref is out of bounds we've exhausted our search.
5359          */
5360 found:
5361         if (bref->key > key_end) {
5362                 *bresp = NULL;
5363                 chain = NULL;
5364         } else {
5365                 *bresp = bref;
5366         }
5367         return(chain);
5368 }
5369
5370 /*
5371  * Locate the specified block array element and delete it.  The element
5372  * must exist.
5373  *
5374  * The spin lock on the related chain must be held.
5375  *
5376  * NOTE: live_count was adjusted when the chain was deleted, so it does not
5377  *       need to be adjusted when we commit the media change.
5378  */
5379 void
5380 hammer2_base_delete(hammer2_chain_t *parent,
5381                     hammer2_blockref_t *base, int count,
5382                     hammer2_chain_t *chain,
5383                     hammer2_blockref_t *obref)
5384 {
5385         hammer2_blockref_t *elm = &chain->bref;
5386         hammer2_blockref_t *scan;
5387         hammer2_key_t key_next;
5388         int i;
5389
5390         /*
5391          * Delete element.  Expect the element to exist.
5392          *
5393          * XXX see caller, flush code not yet sophisticated enough to prevent
5394          *     re-flushed in some cases.
5395          */
5396         key_next = 0; /* max range */
5397         i = hammer2_base_find(parent, base, count, &key_next,
5398                               elm->key, elm->key);
5399         scan = &base[i];
5400         if (i == count || scan->type == HAMMER2_BREF_TYPE_EMPTY ||
5401             scan->key != elm->key ||
5402             ((chain->flags & HAMMER2_CHAIN_BMAPUPD) == 0 &&
5403              scan->keybits != elm->keybits)) {
5404                 hammer2_spin_unex(&parent->core.spin);
5405                 panic("delete base %p element not found at %d/%d elm %p\n",
5406                       base, i, count, elm);
5407                 return;
5408         }
5409
5410         /*
5411          * Update stats and zero the entry.
5412          *
5413          * NOTE: Handle radix == 0 (0 bytes) case.
5414          */
5415         if ((int)(scan->data_off & HAMMER2_OFF_MASK_RADIX)) {
5416                 parent->bref.embed.stats.data_count -= (hammer2_off_t)1 <<
5417                                 (int)(scan->data_off & HAMMER2_OFF_MASK_RADIX);
5418         }
5419         switch(scan->type) {
5420         case HAMMER2_BREF_TYPE_INODE:
5421                 --parent->bref.embed.stats.inode_count;
5422                 /* fall through */
5423         case HAMMER2_BREF_TYPE_DATA:
5424                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5425                         atomic_set_int(&chain->flags,
5426                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5427                 } else {
5428                         if (parent->bref.leaf_count)
5429                                 --parent->bref.leaf_count;
5430                 }
5431                 /* fall through */
5432         case HAMMER2_BREF_TYPE_INDIRECT:
5433                 if (scan->type != HAMMER2_BREF_TYPE_DATA) {
5434                         parent->bref.embed.stats.data_count -=
5435                                 scan->embed.stats.data_count;
5436                         parent->bref.embed.stats.inode_count -=
5437                                 scan->embed.stats.inode_count;
5438                 }
5439                 if (scan->type == HAMMER2_BREF_TYPE_INODE)
5440                         break;
5441                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5442                         atomic_set_int(&chain->flags,
5443                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5444                 } else {
5445                         if (parent->bref.leaf_count <= scan->leaf_count)
5446                                 parent->bref.leaf_count = 0;
5447                         else
5448                                 parent->bref.leaf_count -= scan->leaf_count;
5449                 }
5450                 break;
5451         case HAMMER2_BREF_TYPE_DIRENT:
5452                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5453                         atomic_set_int(&chain->flags,
5454                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5455                 } else {
5456                         if (parent->bref.leaf_count)
5457                                 --parent->bref.leaf_count;
5458                 }
5459         default:
5460                 break;
5461         }
5462
5463         if (obref)
5464                 *obref = *scan;
5465         bzero(scan, sizeof(*scan));
5466
5467         /*
5468          * We can only optimize parent->core.live_zero for live chains.
5469          */
5470         if (parent->core.live_zero == i + 1) {
5471                 while (--i >= 0 && base[i].type == HAMMER2_BREF_TYPE_EMPTY)
5472                         ;
5473                 parent->core.live_zero = i + 1;
5474         }
5475
5476         /*
5477          * Clear appropriate blockmap flags in chain.
5478          */
5479         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_BMAPPED |
5480                                         HAMMER2_CHAIN_BMAPUPD);
5481 }
5482
5483 /*
5484  * Insert the specified element.  The block array must not already have the
5485  * element and must have space available for the insertion.
5486  *
5487  * The spin lock on the related chain must be held.
5488  *
5489  * NOTE: live_count was adjusted when the chain was deleted, so it does not
5490  *       need to be adjusted when we commit the media change.
5491  */
5492 void
5493 hammer2_base_insert(hammer2_chain_t *parent,
5494                     hammer2_blockref_t *base, int count,
5495                     hammer2_chain_t *chain, hammer2_blockref_t *elm)
5496 {
5497         hammer2_key_t key_next;
5498         hammer2_key_t xkey;
5499         int i;
5500         int j;
5501         int k;
5502         int l;
5503         int u = 1;
5504
5505         /*
5506          * Insert new element.  Expect the element to not already exist
5507          * unless we are replacing it.
5508          *
5509          * XXX see caller, flush code not yet sophisticated enough to prevent
5510          *     re-flushed in some cases.
5511          */
5512         key_next = 0; /* max range */
5513         i = hammer2_base_find(parent, base, count, &key_next,
5514                               elm->key, elm->key);
5515
5516         /*
5517          * Shortcut fill optimization, typical ordered insertion(s) may not
5518          * require a search.
5519          */
5520         KKASSERT(i >= 0 && i <= count);
5521
5522         /*
5523          * Set appropriate blockmap flags in chain (if not NULL)
5524          */
5525         if (chain)
5526                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
5527
5528         /*
5529          * Update stats and zero the entry
5530          */
5531         if ((int)(elm->data_off & HAMMER2_OFF_MASK_RADIX)) {
5532                 parent->bref.embed.stats.data_count += (hammer2_off_t)1 <<
5533                                 (int)(elm->data_off & HAMMER2_OFF_MASK_RADIX);
5534         }
5535         switch(elm->type) {
5536         case HAMMER2_BREF_TYPE_INODE:
5537                 ++parent->bref.embed.stats.inode_count;
5538                 /* fall through */
5539         case HAMMER2_BREF_TYPE_DATA:
5540                 if (parent->bref.leaf_count != HAMMER2_BLOCKREF_LEAF_MAX)
5541                         ++parent->bref.leaf_count;
5542                 /* fall through */
5543         case HAMMER2_BREF_TYPE_INDIRECT:
5544                 if (elm->type != HAMMER2_BREF_TYPE_DATA) {
5545                         parent->bref.embed.stats.data_count +=
5546                                 elm->embed.stats.data_count;
5547                         parent->bref.embed.stats.inode_count +=
5548                                 elm->embed.stats.inode_count;
5549                 }
5550                 if (elm->type == HAMMER2_BREF_TYPE_INODE)
5551                         break;
5552                 if (parent->bref.leaf_count + elm->leaf_count <
5553                     HAMMER2_BLOCKREF_LEAF_MAX) {
5554                         parent->bref.leaf_count += elm->leaf_count;
5555                 } else {
5556                         parent->bref.leaf_count = HAMMER2_BLOCKREF_LEAF_MAX;
5557                 }
5558                 break;
5559         case HAMMER2_BREF_TYPE_DIRENT:
5560                 if (parent->bref.leaf_count != HAMMER2_BLOCKREF_LEAF_MAX)
5561                         ++parent->bref.leaf_count;
5562                 break;
5563         default:
5564                 break;
5565         }
5566
5567
5568         /*
5569          * We can only optimize parent->core.live_zero for live chains.
5570          */
5571         if (i == count && parent->core.live_zero < count) {
5572                 i = parent->core.live_zero++;
5573                 base[i] = *elm;
5574                 return;
5575         }
5576
5577         xkey = elm->key + ((hammer2_key_t)1 << elm->keybits) - 1;
5578         if (i != count && (base[i].key < elm->key || xkey >= base[i].key)) {
5579                 hammer2_spin_unex(&parent->core.spin);
5580                 panic("insert base %p overlapping elements at %d elm %p\n",
5581                       base, i, elm);
5582         }
5583
5584         /*
5585          * Try to find an empty slot before or after.
5586          */
5587         j = i;
5588         k = i;
5589         while (j > 0 || k < count) {
5590                 --j;
5591                 if (j >= 0 && base[j].type == HAMMER2_BREF_TYPE_EMPTY) {
5592                         if (j == i - 1) {
5593                                 base[j] = *elm;
5594                         } else {
5595                                 bcopy(&base[j+1], &base[j],
5596                                       (i - j - 1) * sizeof(*base));
5597                                 base[i - 1] = *elm;
5598                         }
5599                         goto validate;
5600                 }
5601                 ++k;
5602                 if (k < count && base[k].type == HAMMER2_BREF_TYPE_EMPTY) {
5603                         bcopy(&base[i], &base[i+1],
5604                               (k - i) * sizeof(hammer2_blockref_t));
5605                         base[i] = *elm;
5606
5607                         /*
5608                          * We can only update parent->core.live_zero for live
5609                          * chains.
5610                          */
5611                         if (parent->core.live_zero <= k)
5612                                 parent->core.live_zero = k + 1;
5613                         u = 2;
5614                         goto validate;
5615                 }
5616         }
5617         panic("hammer2_base_insert: no room!");
5618
5619         /*
5620          * Debugging
5621          */
5622 validate:
5623         key_next = 0;
5624         for (l = 0; l < count; ++l) {
5625                 if (base[l].type) {
5626                         key_next = base[l].key +
5627                                    ((hammer2_key_t)1 << base[l].keybits) - 1;
5628                         break;
5629                 }
5630         }
5631         while (++l < count) {
5632                 if (base[l].type) {
5633                         if (base[l].key <= key_next)
5634                                 panic("base_insert %d %d,%d,%d fail %p:%d", u, i, j, k, base, l);
5635                         key_next = base[l].key +
5636                                    ((hammer2_key_t)1 << base[l].keybits) - 1;
5637
5638                 }
5639         }
5640
5641 }
5642
5643 #if 0
5644
5645 /*
5646  * Sort the blockref array for the chain.  Used by the flush code to
5647  * sort the blockref[] array.
5648  *
5649  * The chain must be exclusively locked AND spin-locked.
5650  */
5651 typedef hammer2_blockref_t *hammer2_blockref_p;
5652
5653 static
5654 int
5655 hammer2_base_sort_callback(const void *v1, const void *v2)
5656 {
5657         hammer2_blockref_p bref1 = *(const hammer2_blockref_p *)v1;
5658         hammer2_blockref_p bref2 = *(const hammer2_blockref_p *)v2;
5659
5660         /*
5661          * Make sure empty elements are placed at the end of the array
5662          */
5663         if (bref1->type == HAMMER2_BREF_TYPE_EMPTY) {
5664                 if (bref2->type == HAMMER2_BREF_TYPE_EMPTY)
5665                         return(0);
5666                 return(1);
5667         } else if (bref2->type == HAMMER2_BREF_TYPE_EMPTY) {
5668                 return(-1);
5669         }
5670
5671         /*
5672          * Sort by key
5673          */
5674         if (bref1->key < bref2->key)
5675                 return(-1);
5676         if (bref1->key > bref2->key)
5677                 return(1);
5678         return(0);
5679 }
5680
5681 void
5682 hammer2_base_sort(hammer2_chain_t *chain)
5683 {
5684         hammer2_blockref_t *base;
5685         int count;
5686
5687         switch(chain->bref.type) {
5688         case HAMMER2_BREF_TYPE_INODE:
5689                 /*
5690                  * Special shortcut for embedded data returns the inode
5691                  * itself.  Callers must detect this condition and access
5692                  * the embedded data (the strategy code does this for us).
5693                  *
5694                  * This is only applicable to regular files and softlinks.
5695                  */
5696                 if (chain->data->ipdata.meta.op_flags &
5697                     HAMMER2_OPFLAG_DIRECTDATA) {
5698                         return;
5699                 }
5700                 base = &chain->data->ipdata.u.blockset.blockref[0];
5701                 count = HAMMER2_SET_COUNT;
5702                 break;
5703         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
5704         case HAMMER2_BREF_TYPE_INDIRECT:
5705                 /*
5706                  * Optimize indirect blocks in the INITIAL state to avoid
5707                  * I/O.
5708                  */
5709                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) == 0);
5710                 base = &chain->data->npdata[0];
5711                 count = chain->bytes / sizeof(hammer2_blockref_t);
5712                 break;
5713         case HAMMER2_BREF_TYPE_VOLUME:
5714                 base = &chain->data->voldata.sroot_blockset.blockref[0];
5715                 count = HAMMER2_SET_COUNT;
5716                 break;
5717         case HAMMER2_BREF_TYPE_FREEMAP:
5718                 base = &chain->data->blkset.blockref[0];
5719                 count = HAMMER2_SET_COUNT;
5720                 break;
5721         default:
5722                 kprintf("hammer2_chain_lookup: unrecognized "
5723                         "blockref(A) type: %d",
5724                         chain->bref.type);
5725                 while (1)
5726                         tsleep(&base, 0, "dead", 0);
5727                 panic("hammer2_chain_lookup: unrecognized "
5728                       "blockref(A) type: %d",
5729                       chain->bref.type);
5730                 base = NULL;    /* safety */
5731                 count = 0;      /* safety */
5732         }
5733         kqsort(base, count, sizeof(*base), hammer2_base_sort_callback);
5734 }
5735
5736 #endif
5737
5738 /*
5739  * Chain memory management
5740  */
5741 void
5742 hammer2_chain_wait(hammer2_chain_t *chain)
5743 {
5744         tsleep(chain, 0, "chnflw", 1);
5745 }
5746
5747 const hammer2_media_data_t *
5748 hammer2_chain_rdata(hammer2_chain_t *chain)
5749 {
5750         KKASSERT(chain->data != NULL);
5751         return (chain->data);
5752 }
5753
5754 hammer2_media_data_t *
5755 hammer2_chain_wdata(hammer2_chain_t *chain)
5756 {
5757         KKASSERT(chain->data != NULL);
5758         return (chain->data);
5759 }
5760
5761 /*
5762  * Set the check data for a chain.  This can be a heavy-weight operation
5763  * and typically only runs on-flush.  For file data check data is calculated
5764  * when the logical buffers are flushed.
5765  */
5766 void
5767 hammer2_chain_setcheck(hammer2_chain_t *chain, void *bdata)
5768 {
5769         chain->bref.flags &= ~HAMMER2_BREF_FLAG_ZERO;
5770
5771         switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
5772         case HAMMER2_CHECK_NONE:
5773                 break;
5774         case HAMMER2_CHECK_DISABLED:
5775                 break;
5776         case HAMMER2_CHECK_ISCSI32:
5777                 chain->bref.check.iscsi32.value =
5778                         hammer2_icrc32(bdata, chain->bytes);
5779                 break;
5780         case HAMMER2_CHECK_XXHASH64:
5781                 chain->bref.check.xxhash64.value =
5782                         XXH64(bdata, chain->bytes, XXH_HAMMER2_SEED);
5783                 break;
5784         case HAMMER2_CHECK_SHA192:
5785                 {
5786                         SHA256_CTX hash_ctx;
5787                         union {
5788                                 uint8_t digest[SHA256_DIGEST_LENGTH];
5789                                 uint64_t digest64[SHA256_DIGEST_LENGTH/8];
5790                         } u;
5791
5792                         SHA256_Init(&hash_ctx);
5793                         SHA256_Update(&hash_ctx, bdata, chain->bytes);
5794                         SHA256_Final(u.digest, &hash_ctx);
5795                         u.digest64[2] ^= u.digest64[3];
5796                         bcopy(u.digest,
5797                               chain->bref.check.sha192.data,
5798                               sizeof(chain->bref.check.sha192.data));
5799                 }
5800                 break;
5801         case HAMMER2_CHECK_FREEMAP:
5802                 chain->bref.check.freemap.icrc32 =
5803                         hammer2_icrc32(bdata, chain->bytes);
5804                 break;
5805         default:
5806                 kprintf("hammer2_chain_setcheck: unknown check type %02x\n",
5807                         chain->bref.methods);
5808                 break;
5809         }
5810 }
5811
5812 /*
5813  * Characterize a failed check code and try to trace back to the inode.
5814  */
5815 static void
5816 hammer2_characterize_failed_chain(hammer2_chain_t *chain, uint64_t check,
5817                                   int bits)
5818 {
5819         hammer2_chain_t *lchain;
5820         hammer2_chain_t *ochain;
5821
5822         kprintf("chain %016jx.%02x (%s) meth=%02x CHECK FAIL "
5823                 "(flags=%08x, bref/data ",
5824                 chain->bref.data_off,
5825                 chain->bref.type,
5826                 hammer2_bref_type_str(&chain->bref),
5827                 chain->bref.methods,
5828                 chain->flags);
5829         if (bits == 32) {
5830                 kprintf("%08x/%08x)\n",
5831                         chain->bref.check.iscsi32.value,
5832                         (uint32_t)check);
5833         } else {
5834                 kprintf("%016jx/%016jx)\n",
5835                         chain->bref.check.xxhash64.value,
5836                         check);
5837         }
5838
5839         /*
5840          * Run up the chains to try to find the governing inode so we
5841          * can report it.
5842          *
5843          * XXX This error reporting is not really MPSAFE
5844          */
5845         ochain = chain;
5846         lchain = chain;
5847         while (chain && chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
5848                 lchain = chain;
5849                 chain = chain->parent;
5850         }
5851
5852         if (chain && chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
5853             ((chain->bref.flags & HAMMER2_BREF_FLAG_PFSROOT) == 0 ||
5854              (lchain->bref.key & HAMMER2_DIRHASH_VISIBLE))) {
5855                 kprintf("   Resides at/in inode %ld\n",
5856                         chain->bref.key);
5857         } else if (chain && chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
5858                 kprintf("   Resides in inode index - CRITICAL!!!\n");
5859         } else {
5860                 kprintf("   Resides in root index - CRITICAL!!!\n");
5861         }
5862         if (ochain->hmp) {
5863                 const char *pfsname = "UNKNOWN";
5864                 int i;
5865
5866                 if (ochain->pmp) {
5867                         for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
5868                                 if (ochain->pmp->pfs_hmps[i] == ochain->hmp &&
5869                                     ochain->pmp->pfs_names[i]) {
5870                                         pfsname = ochain->pmp->pfs_names[i];
5871                                         break;
5872                                 }
5873                         }
5874                 }
5875                 kprintf("   In pfs %s on device %s\n",
5876                         pfsname, ochain->hmp->devrepname);
5877         }
5878 }
5879
5880 int
5881 hammer2_chain_testcheck(hammer2_chain_t *chain, void *bdata)
5882 {
5883         uint32_t check32;
5884         uint64_t check64;
5885         int r;
5886
5887         if (chain->bref.flags & HAMMER2_BREF_FLAG_ZERO)
5888                 return 1;
5889
5890         switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
5891         case HAMMER2_CHECK_NONE:
5892                 r = 1;
5893                 break;
5894         case HAMMER2_CHECK_DISABLED:
5895                 r = 1;
5896                 break;
5897         case HAMMER2_CHECK_ISCSI32:
5898                 check32 = hammer2_icrc32(bdata, chain->bytes);
5899                 r = (chain->bref.check.iscsi32.value == check32);
5900                 if (r == 0) {
5901                         hammer2_characterize_failed_chain(chain, check32, 32);
5902                 }
5903                 hammer2_process_icrc32 += chain->bytes;
5904                 break;
5905         case HAMMER2_CHECK_XXHASH64:
5906                 check64 = XXH64(bdata, chain->bytes, XXH_HAMMER2_SEED);
5907                 r = (chain->bref.check.xxhash64.value == check64);
5908                 if (r == 0) {
5909                         hammer2_characterize_failed_chain(chain, check64, 64);
5910                 }
5911                 hammer2_process_xxhash64 += chain->bytes;
5912                 break;
5913         case HAMMER2_CHECK_SHA192:
5914                 {
5915                         SHA256_CTX hash_ctx;
5916                         union {
5917                                 uint8_t digest[SHA256_DIGEST_LENGTH];
5918                                 uint64_t digest64[SHA256_DIGEST_LENGTH/8];
5919                         } u;
5920
5921                         SHA256_Init(&hash_ctx);
5922                         SHA256_Update(&hash_ctx, bdata, chain->bytes);
5923                         SHA256_Final(u.digest, &hash_ctx);
5924                         u.digest64[2] ^= u.digest64[3];
5925                         if (bcmp(u.digest,
5926                                  chain->bref.check.sha192.data,
5927                                  sizeof(chain->bref.check.sha192.data)) == 0) {
5928                                 r = 1;
5929                         } else {
5930                                 r = 0;
5931                                 kprintf("chain %016jx.%02x meth=%02x "
5932                                         "CHECK FAIL\n",
5933                                         chain->bref.data_off,
5934                                         chain->bref.type,
5935                                         chain->bref.methods);
5936                         }
5937                 }
5938                 break;
5939         case HAMMER2_CHECK_FREEMAP:
5940                 r = (chain->bref.check.freemap.icrc32 ==
5941                      hammer2_icrc32(bdata, chain->bytes));
5942                 if (r == 0) {
5943                         kprintf("chain %016jx.%02x meth=%02x "
5944                                 "CHECK FAIL\n",
5945                                 chain->bref.data_off,
5946                                 chain->bref.type,
5947                                 chain->bref.methods);
5948                         kprintf("freemap.icrc %08x icrc32 %08x (%d)\n",
5949                                 chain->bref.check.freemap.icrc32,
5950                                 hammer2_icrc32(bdata, chain->bytes),
5951                                                chain->bytes);
5952                         if (chain->dio)
5953                                 kprintf("dio %p buf %016jx,%d bdata %p/%p\n",
5954                                         chain->dio, chain->dio->bp->b_loffset,
5955                                         chain->dio->bp->b_bufsize, bdata,
5956                                         chain->dio->bp->b_data);
5957                 }
5958
5959                 break;
5960         default:
5961                 kprintf("hammer2_chain_setcheck: unknown check type %02x\n",
5962                         chain->bref.methods);
5963                 r = 1;
5964                 break;
5965         }
5966         return r;
5967 }
5968
5969 /*
5970  * Acquire the chain and parent representing the specified inode for the
5971  * device at the specified cluster index.
5972  *
5973  * The flags passed in are LOOKUP flags, not RESOLVE flags.
5974  *
5975  * If we are unable to locate the inode, HAMMER2_ERROR_EIO is returned and
5976  * *chainp will be NULL.  *parentp may still be set error or not, or NULL
5977  * if the parent itself could not be resolved.
5978  *
5979  * The caller may pass-in a locked *parentp and/or *chainp, or neither.
5980  * They will be unlocked and released by this function.  The *parentp and
5981  * *chainp representing the located inode are returned locked.
5982  */
5983 int
5984 hammer2_chain_inode_find(hammer2_pfs_t *pmp, hammer2_key_t inum,
5985                          int clindex, int flags,
5986                          hammer2_chain_t **parentp, hammer2_chain_t **chainp)
5987 {
5988         hammer2_chain_t *parent;
5989         hammer2_chain_t *rchain;
5990         hammer2_key_t key_dummy;
5991         hammer2_inode_t *ip;
5992         int resolve_flags;
5993         int error;
5994
5995         resolve_flags = (flags & HAMMER2_LOOKUP_SHARED) ?
5996                         HAMMER2_RESOLVE_SHARED : 0;
5997
5998         /*
5999          * Caller expects us to replace these.
6000          */
6001         if (*chainp) {
6002                 hammer2_chain_unlock(*chainp);
6003                 hammer2_chain_drop(*chainp);
6004                 *chainp = NULL;
6005         }
6006         if (*parentp) {
6007                 hammer2_chain_unlock(*parentp);
6008                 hammer2_chain_drop(*parentp);
6009                 *parentp = NULL;
6010         }
6011
6012         /*
6013          * Be very careful, this is a backend function and we CANNOT
6014          * lock any frontend inode structure we find.  But we have to
6015          * look the inode up this way first in case it exists but is
6016          * detached from the radix tree.
6017          */
6018         ip = hammer2_inode_lookup(pmp, inum);
6019         if (ip) {
6020                 *chainp = hammer2_inode_chain_and_parent(ip, clindex,
6021                                                        parentp,
6022                                                        resolve_flags);
6023                 hammer2_inode_drop(ip);
6024                 if (*chainp)
6025                         return 0;
6026                 hammer2_chain_unlock(*chainp);
6027                 hammer2_chain_drop(*chainp);
6028                 *chainp = NULL;
6029                 if (*parentp) {
6030                         hammer2_chain_unlock(*parentp);
6031                         hammer2_chain_drop(*parentp);
6032                         *parentp = NULL;
6033                 }
6034         }
6035
6036         /*
6037          * Inodes hang off of the iroot (bit 63 is clear, differentiating
6038          * inodes from root directory entries in the key lookup).
6039          */
6040         parent = hammer2_inode_chain(pmp->iroot, clindex, resolve_flags);
6041         rchain = NULL;
6042         if (parent) {
6043                 rchain = hammer2_chain_lookup(&parent, &key_dummy,
6044                                               inum, inum,
6045                                               &error, flags);
6046         } else {
6047                 error = HAMMER2_ERROR_EIO;
6048         }
6049         *parentp = parent;
6050         *chainp = rchain;
6051
6052         return error;
6053 }
6054
6055 /*
6056  * Used by the bulkscan code to snapshot the synchronized storage for
6057  * a volume, allowing it to be scanned concurrently against normal
6058  * operation.
6059  */
6060 hammer2_chain_t *
6061 hammer2_chain_bulksnap(hammer2_dev_t *hmp)
6062 {
6063         hammer2_chain_t *copy;
6064
6065         copy = hammer2_chain_alloc(hmp, hmp->spmp, &hmp->vchain.bref);
6066         copy->data = kmalloc(sizeof(copy->data->voldata),
6067                              hmp->mchain,
6068                              M_WAITOK | M_ZERO);
6069         hammer2_voldata_lock(hmp);
6070         copy->data->voldata = hmp->volsync;
6071         hammer2_voldata_unlock(hmp);
6072
6073         return copy;
6074 }
6075
6076 void
6077 hammer2_chain_bulkdrop(hammer2_chain_t *copy)
6078 {
6079         KKASSERT(copy->bref.type == HAMMER2_BREF_TYPE_VOLUME);
6080         KKASSERT(copy->data);
6081         kfree(copy->data, copy->hmp->mchain);
6082         copy->data = NULL;
6083         atomic_add_long(&hammer2_chain_allocs, -1);
6084         hammer2_chain_drop(copy);
6085 }
6086
6087 /*
6088  * Returns non-zero if the chain (INODE or DIRENT) matches the
6089  * filename.
6090  */
6091 int
6092 hammer2_chain_dirent_test(hammer2_chain_t *chain, const char *name,
6093                           size_t name_len)
6094 {
6095         const hammer2_inode_data_t *ripdata;
6096         const hammer2_dirent_head_t *den;
6097
6098         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
6099                 ripdata = &chain->data->ipdata;
6100                 if (ripdata->meta.name_len == name_len &&
6101                     bcmp(ripdata->filename, name, name_len) == 0) {
6102                         return 1;
6103                 }
6104         }
6105         if (chain->bref.type == HAMMER2_BREF_TYPE_DIRENT &&
6106            chain->bref.embed.dirent.namlen == name_len) {
6107                 den = &chain->bref.embed.dirent;
6108                 if (name_len > sizeof(chain->bref.check.buf) &&
6109                     bcmp(chain->data->buf, name, name_len) == 0) {
6110                         return 1;
6111                 }
6112                 if (name_len <= sizeof(chain->bref.check.buf) &&
6113                     bcmp(chain->bref.check.buf, name, name_len) == 0) {
6114                         return 1;
6115                 }
6116         }
6117         return 0;
6118 }