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).
  90  */
  91 RB_GENERATE(hammer2_chain_tree, hammer2_chain, rbnode, hammer2_chain_cmp);
  92
  93 int
  94 hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2)
  95 {
  96         hammer2_key_t c1_beg;
  97         hammer2_key_t c1_end;
  98         hammer2_key_t c2_beg;
  99         hammer2_key_t c2_end;
 100
 101         /*
 102          * Compare chains.  Overlaps are not supposed to happen and catch
 103          * any software issues early we count overlaps as a match.
 104          */
 105         c1_beg = chain1->bref.key;
 106         c1_end = c1_beg + ((hammer2_key_t)1 << chain1->bref.keybits) - 1;
 107         c2_beg = chain2->bref.key;
 108         c2_end = c2_beg + ((hammer2_key_t)1 << chain2->bref.keybits) - 1;
 109
 110         if (c1_end < c2_beg)    /* fully to the left */
 111                 return(-1);
 112         if (c1_beg > c2_end)    /* fully to the right */
 113                 return(1);
 114         return(0);              /* overlap (must not cross edge boundary) */
 115 }
 116
 117 /*
 118  * Assert that a chain has no media data associated with it.
 119  */
 120 static __inline void
 121 hammer2_chain_assert_no_data(hammer2_chain_t *chain)
 122 {
 123         KKASSERT(chain->dio == NULL);
 124         if (chain->bref.type != HAMMER2_BREF_TYPE_VOLUME &&
 125             chain->bref.type != HAMMER2_BREF_TYPE_FREEMAP &&
 126             chain->data) {
 127                 panic("hammer2_chain_assert_no_data: chain %p still has data",
 128                     chain);
 129         }
 130 }
 131
 132 /*
 133  * Make a chain visible to the flusher.  The flusher operates using a top-down
 134  * recursion based on the ONFLUSH flag.  It locates MODIFIED and UPDATE chains,
 135  * flushes them, and updates blocks back to the volume root.
 136  *
 137  * This routine sets the ONFLUSH flag upward from the triggering chain until
 138  * it hits an inode root or the volume root.  Inode chains serve as inflection
 139  * points, requiring the flusher to bridge across trees.  Inodes include
 140  * regular inodes, PFS roots (pmp->iroot), and the media super root
 141  * (spmp->iroot).
 142  */
 143 void
 144 hammer2_chain_setflush(hammer2_chain_t *chain)
 145 {
 146         hammer2_chain_t *parent;
 147
 148         if ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
 149                 hammer2_spin_sh(&chain->core.spin);
 150                 while ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
 151                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONFLUSH);
 152                         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
 153                                 break;
 154                         if ((parent = chain->parent) == NULL)
 155                                 break;
 156                         hammer2_spin_sh(&parent->core.spin);
 157                         hammer2_spin_unsh(&chain->core.spin);
 158                         chain = parent;
 159                 }
 160                 hammer2_spin_unsh(&chain->core.spin);
 161         }
 162 }
 163
 164 /*
 165  * Allocate a new disconnected chain element representing the specified
 166  * bref.  chain->refs is set to 1 and the passed bref is copied to
 167  * chain->bref.  chain->bytes is derived from the bref.
 168  *
 169  * chain->pmp inherits pmp unless the chain is an inode (other than the
 170  * super-root inode).
 171  *
 172  * NOTE: Returns a referenced but unlocked (because there is no core) chain.
 173  */
 174 hammer2_chain_t *
 175 hammer2_chain_alloc(hammer2_dev_t *hmp, hammer2_pfs_t *pmp,
 176                     hammer2_blockref_t *bref)
 177 {
 178         hammer2_chain_t *chain;
 179         u_int bytes;
 180
 181         /*
 182          * Special case - radix of 0 indicates a chain that does not
 183          * need a data reference (context is completely embedded in the
 184          * bref).
 185          */
 186         if ((int)(bref->data_off & HAMMER2_OFF_MASK_RADIX))
 187                 bytes = 1U << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
 188         else
 189                 bytes = 0;
 190
 191         atomic_add_long(&hammer2_chain_allocs, 1);
 192
 193         /*
 194          * Construct the appropriate system structure.
 195          */
 196         switch(bref->type) {
 197         case HAMMER2_BREF_TYPE_DIRENT:
 198         case HAMMER2_BREF_TYPE_INODE:
 199         case HAMMER2_BREF_TYPE_INDIRECT:
 200         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 201         case HAMMER2_BREF_TYPE_DATA:
 202         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
 203                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
 204                 break;
 205         case HAMMER2_BREF_TYPE_VOLUME:
 206         case HAMMER2_BREF_TYPE_FREEMAP:
 207                 /*
 208                  * Only hammer2_chain_bulksnap() calls this function with these
 209                  * types.
 210                  */
 211                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
 212                 break;
 213         default:
 214                 chain = NULL;
 215                 panic("hammer2_chain_alloc: unrecognized blockref type: %d",
 216                       bref->type);
 217         }
 218
 219         /*
 220          * Initialize the new chain structure.  pmp must be set to NULL for
 221          * chains belonging to the super-root topology of a device mount.
 222          */
 223         if (pmp == hmp->spmp)
 224                 chain->pmp = NULL;
 225         else
 226                 chain->pmp = pmp;
 227
 228         chain->hmp = hmp;
 229         chain->bref = *bref;
 230         chain->bytes = bytes;
 231         chain->refs = 1;
 232         chain->flags = HAMMER2_CHAIN_ALLOCATED;
 233         lockinit(&chain->diolk, "chdio", 0, 0);
 234
 235         /*
 236          * Set the PFS boundary flag if this chain represents a PFS root.
 237          */
 238         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
 239                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_PFSBOUNDARY);
 240         hammer2_chain_core_init(chain);
 241
 242         return (chain);
 243 }
 244
 245 /*
 246  * Initialize a chain's core structure.  This structure used to be allocated
 247  * but is now embedded.
 248  *
 249  * The core is not locked.  No additional refs on the chain are made.
 250  * (trans) must not be NULL if (core) is not NULL.
 251  */
 252 void
 253 hammer2_chain_core_init(hammer2_chain_t *chain)
 254 {
 255         /*
 256          * Fresh core under nchain (no multi-homing of ochain's
 257          * sub-tree).
 258          */
 259         RB_INIT(&chain->core.rbtree);   /* live chains */
 260         hammer2_mtx_init(&chain->lock, "h2chain");
 261 }
 262
 263 /*
 264  * Add a reference to a chain element, preventing its destruction.
 265  *
 266  * (can be called with spinlock held)
 267  */
 268 void
 269 hammer2_chain_ref(hammer2_chain_t *chain)
 270 {
 271         if (atomic_fetchadd_int(&chain->refs, 1) == 0) {
 272                 /*
 273                  * Just flag that the chain was used and should be recycled
 274                  * on the LRU if it encounters it later.
 275                  */
 276                 if (chain->flags & HAMMER2_CHAIN_ONLRU)
 277                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_LRUHINT);
 278
 279 #if 0
 280                 /*
 281                  * REMOVED - reduces contention, lru_list is more heuristical
 282                  * now.
 283                  *
 284                  * 0->non-zero transition must ensure that chain is removed
 285                  * from the LRU list.
 286                  *
 287                  * NOTE: Already holding lru_spin here so we cannot call
 288                  *       hammer2_chain_ref() to get it off lru_list, do
 289                  *       it manually.
 290                  */
 291                 if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 292                         hammer2_pfs_t *pmp = chain->pmp;
 293                         hammer2_spin_ex(&pmp->lru_spin);
 294                         if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 295                                 atomic_add_int(&pmp->lru_count, -1);
 296                                 atomic_clear_int(&chain->flags,
 297                                                  HAMMER2_CHAIN_ONLRU);
 298                                 TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 299                         }
 300                         hammer2_spin_unex(&pmp->lru_spin);
 301                 }
 302 #endif
 303         }
 304 }
 305
 306 /*
 307  * Ref a locked chain and force the data to be held across an unlock.
 308  * Chain must be currently locked.  The user of the chain who desires
 309  * to release the hold must call hammer2_chain_lock_unhold() to relock
 310  * and unhold the chain, then unlock normally, or may simply call
 311  * hammer2_chain_drop_unhold() (which is safer against deadlocks).
 312  */
 313 void
 314 hammer2_chain_ref_hold(hammer2_chain_t *chain)
 315 {
 316         atomic_add_int(&chain->lockcnt, 1);
 317         hammer2_chain_ref(chain);
 318 }
 319
 320 /*
 321  * Insert the chain in the core rbtree.
 322  *
 323  * Normal insertions are placed in the live rbtree.  Insertion of a deleted
 324  * chain is a special case used by the flush code that is placed on the
 325  * unstaged deleted list to avoid confusing the live view.
 326  */
 327 #define HAMMER2_CHAIN_INSERT_SPIN       0x0001
 328 #define HAMMER2_CHAIN_INSERT_LIVE       0x0002
 329 #define HAMMER2_CHAIN_INSERT_RACE       0x0004
 330
 331 static
 332 int
 333 hammer2_chain_insert(hammer2_chain_t *parent, hammer2_chain_t *chain,
 334                      int flags, int generation)
 335 {
 336         hammer2_chain_t *xchain;
 337         int error = 0;
 338
 339         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
 340                 hammer2_spin_ex(&parent->core.spin);
 341
 342         /*
 343          * Interlocked by spinlock, check for race
 344          */
 345         if ((flags & HAMMER2_CHAIN_INSERT_RACE) &&
 346             parent->core.generation != generation) {
 347                 error = HAMMER2_ERROR_EAGAIN;
 348                 goto failed;
 349         }
 350
 351         /*
 352          * Insert chain
 353          */
 354         xchain = RB_INSERT(hammer2_chain_tree, &parent->core.rbtree, chain);
 355         KASSERT(xchain == NULL,
 356                 ("hammer2_chain_insert: collision %p %p (key=%016jx)",
 357                 chain, xchain, chain->bref.key));
 358         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
 359         chain->parent = parent;
 360         ++parent->core.chain_count;
 361         ++parent->core.generation;      /* XXX incs for _get() too, XXX */
 362
 363         /*
 364          * We have to keep track of the effective live-view blockref count
 365          * so the create code knows when to push an indirect block.
 366          */
 367         if (flags & HAMMER2_CHAIN_INSERT_LIVE)
 368                 atomic_add_int(&parent->core.live_count, 1);
 369 failed:
 370         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
 371                 hammer2_spin_unex(&parent->core.spin);
 372         return error;
 373 }
 374
 375 /*
 376  * Drop the caller's reference to the chain.  When the ref count drops to
 377  * zero this function will try to disassociate the chain from its parent and
 378  * deallocate it, then recursely drop the parent using the implied ref
 379  * from the chain's chain->parent.
 380  *
 381  * Nobody should own chain's mutex on the 1->0 transition, unless this drop
 382  * races an acquisition by another cpu.  Therefore we can loop if we are
 383  * unable to acquire the mutex, and refs is unlikely to be 1 unless we again
 384  * race against another drop.
 385  */
 386 static hammer2_chain_t *hammer2_chain_lastdrop(hammer2_chain_t *chain,
 387                                 int depth);
 388 static void hammer2_chain_lru_flush(hammer2_pfs_t *pmp);
 389
 390 void
 391 hammer2_chain_drop(hammer2_chain_t *chain)
 392 {
 393         u_int refs;
 394
 395         if (hammer2_debug & 0x200000)
 396                 Debugger("drop");
 397
 398         KKASSERT(chain->refs > 0);
 399
 400         while (chain) {
 401                 refs = chain->refs;
 402                 cpu_ccfence();
 403                 KKASSERT(refs > 0);
 404
 405                 if (refs == 1) {
 406                         if (hammer2_mtx_ex_try(&chain->lock) == 0)
 407                                 chain = hammer2_chain_lastdrop(chain, 0);
 408                         /* retry the same chain, or chain from lastdrop */
 409                 } else {
 410                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
 411                                 break;
 412                         /* retry the same chain */
 413                 }
 414                 cpu_pause();
 415         }
 416 }
 417
 418 /*
 419  * Unhold a held and probably not-locked chain, ensure that the data is
 420  * dropped on the 1->0 transition of lockcnt by obtaining an exclusive
 421  * lock and then simply unlocking the chain.
 422  */
 423 void
 424 hammer2_chain_unhold(hammer2_chain_t *chain)
 425 {
 426         u_int lockcnt;
 427         int iter = 0;
 428
 429         for (;;) {
 430                 lockcnt = chain->lockcnt;
 431                 cpu_ccfence();
 432                 if (lockcnt > 1) {
 433                         if (atomic_cmpset_int(&chain->lockcnt,
 434                                               lockcnt, lockcnt - 1)) {
 435                                 break;
 436                         }
 437                 } else if (hammer2_mtx_ex_try(&chain->lock) == 0) {
 438                         hammer2_chain_unlock(chain);
 439                         break;
 440                 } else {
 441                         /*
 442                          * This situation can easily occur on SMP due to
 443                          * the gap inbetween the 1->0 transition and the
 444                          * final unlock.  We cannot safely block on the
 445                          * mutex because lockcnt might go above 1.
 446                          *
 447                          * XXX Sleep for one tick if it takes too long.
 448                          */
 449                         if (++iter > 1000) {
 450                                 if (iter > 1000 + hz) {
 451                                         kprintf("hammer2: h2race1 %p\n", chain);
 452                                         iter = 1000;
 453                                 }
 454                                 tsleep(&iter, 0, "h2race1", 1);
 455                         }
 456                         cpu_pause();
 457                 }
 458         }
 459 }
 460
 461 void
 462 hammer2_chain_drop_unhold(hammer2_chain_t *chain)
 463 {
 464         hammer2_chain_unhold(chain);
 465         hammer2_chain_drop(chain);
 466 }
 467
 468 void
 469 hammer2_chain_rehold(hammer2_chain_t *chain)
 470 {
 471         hammer2_chain_lock(chain, HAMMER2_RESOLVE_SHARED);
 472         atomic_add_int(&chain->lockcnt, 1);
 473         hammer2_chain_unlock(chain);
 474 }
 475
 476 /*
 477  * Handles the (potential) last drop of chain->refs from 1->0.  Called with
 478  * the mutex exclusively locked, refs == 1, and lockcnt 0.  SMP races are
 479  * possible against refs and lockcnt.  We must dispose of the mutex on chain.
 480  *
 481  * This function returns an unlocked chain for recursive drop or NULL.  It
 482  * can return the same chain if it determines it has raced another ref.
 483  *
 484  * --
 485  *
 486  * When two chains need to be recursively dropped we use the chain we
 487  * would otherwise free to placehold the additional chain.  It's a bit
 488  * convoluted but we can't just recurse without potentially blowing out
 489  * the kernel stack.
 490  *
 491  * The chain cannot be freed if it has any children.
 492  * The chain cannot be freed if flagged MODIFIED unless we can dispose of it.
 493  * The chain cannot be freed if flagged UPDATE unless we can dispose of it.
 494  * Any dedup registration can remain intact.
 495  *
 496  * The core spinlock is allowed to nest child-to-parent (not parent-to-child).
 497  */
 498 static
 499 hammer2_chain_t *
 500 hammer2_chain_lastdrop(hammer2_chain_t *chain, int depth)
 501 {
 502         hammer2_pfs_t *pmp;
 503         hammer2_dev_t *hmp;
 504         hammer2_chain_t *parent;
 505         hammer2_chain_t *rdrop;
 506
 507         /*
 508          * We need chain's spinlock to interlock the sub-tree test.
 509          * We already have chain's mutex, protecting chain->parent.
 510          *
 511          * Remember that chain->refs can be in flux.
 512          */
 513         hammer2_spin_ex(&chain->core.spin);
 514
 515         if (chain->parent != NULL) {
 516                 /*
 517                  * If the chain has a parent the UPDATE bit prevents scrapping
 518                  * as the chain is needed to properly flush the parent.  Try
 519                  * to complete the 1->0 transition and return NULL.  Retry
 520                  * (return chain) if we are unable to complete the 1->0
 521                  * transition, else return NULL (nothing more to do).
 522                  *
 523                  * If the chain has a parent the MODIFIED bit prevents
 524                  * scrapping.
 525                  *
 526                  * Chains with UPDATE/MODIFIED are *not* put on the LRU list!
 527                  */
 528                 if (chain->flags & (HAMMER2_CHAIN_UPDATE |
 529                                     HAMMER2_CHAIN_MODIFIED)) {
 530                         if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 531                                 hammer2_spin_unex(&chain->core.spin);
 532                                 hammer2_chain_assert_no_data(chain);
 533                                 hammer2_mtx_unlock(&chain->lock);
 534                                 chain = NULL;
 535                         } else {
 536                                 hammer2_spin_unex(&chain->core.spin);
 537                                 hammer2_mtx_unlock(&chain->lock);
 538                         }
 539                         return (chain);
 540                 }
 541                 /* spinlock still held */
 542         } else if (chain->bref.type == HAMMER2_BREF_TYPE_VOLUME ||
 543                    chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP) {
 544                 /*
 545                  * Retain the static vchain and fchain.  Clear bits that
 546                  * are not relevant.  Do not clear the MODIFIED bit,
 547                  * and certainly do not put it on the delayed-flush queue.
 548                  */
 549                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 550         } else {
 551                 /*
 552                  * The chain has no parent and can be flagged for destruction.
 553                  * Since it has no parent, UPDATE can also be cleared.
 554                  */
 555                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
 556                 if (chain->flags & HAMMER2_CHAIN_UPDATE)
 557                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 558
 559                 /*
 560                  * If the chain has children we must propagate the DESTROY
 561                  * flag downward and rip the disconnected topology apart.
 562                  * This is accomplished by calling hammer2_flush() on the
 563                  * chain.
 564                  *
 565                  * Any dedup is already handled by the underlying DIO, so
 566                  * we do not have to specifically flush it here.
 567                  */
 568                 if (chain->core.chain_count) {
 569                         hammer2_spin_unex(&chain->core.spin);
 570                         hammer2_flush(chain, HAMMER2_FLUSH_TOP |
 571                                              HAMMER2_FLUSH_ALL);
 572                         hammer2_mtx_unlock(&chain->lock);
 573
 574                         return(chain);  /* retry drop */
 575                 }
 576
 577                 /*
 578                  * Otherwise we can scrap the MODIFIED bit if it is set,
 579                  * and continue along the freeing path.
 580                  *
 581                  * Be sure to clean-out any dedup bits.  Without a parent
 582                  * this chain will no longer be visible to the flush code.
 583                  * Easy check data_off to avoid the volume root.
 584                  */
 585                 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
 586                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 587                         atomic_add_long(&hammer2_count_modified_chains, -1);
 588                         if (chain->pmp)
 589                                 hammer2_pfs_memory_wakeup(chain->pmp);
 590                 }
 591                 /* spinlock still held */
 592         }
 593
 594         /* spinlock still held */
 595
 596         /*
 597          * If any children exist we must leave the chain intact with refs == 0.
 598          * They exist because chains are retained below us which have refs or
 599          * may require flushing.
 600          *
 601          * Retry (return chain) if we fail to transition the refs to 0, else
 602          * return NULL indication nothing more to do.
 603          *
 604          * Chains with children are NOT put on the LRU list.
 605          */
 606         if (chain->core.chain_count) {
 607                 if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 608                         hammer2_spin_unex(&chain->core.spin);
 609                         hammer2_chain_assert_no_data(chain);
 610                         hammer2_mtx_unlock(&chain->lock);
 611                         chain = NULL;
 612                 } else {
 613                         hammer2_spin_unex(&chain->core.spin);
 614                         hammer2_mtx_unlock(&chain->lock);
 615                 }
 616                 return (chain);
 617         }
 618         /* spinlock still held */
 619         /* no chains left under us */
 620
 621         /*
 622          * chain->core has no children left so no accessors can get to our
 623          * chain from there.  Now we have to lock the parent core to interlock
 624          * remaining possible accessors that might bump chain's refs before
 625          * we can safely drop chain's refs with intent to free the chain.
 626          */
 627         hmp = chain->hmp;
 628         pmp = chain->pmp;       /* can be NULL */
 629         rdrop = NULL;
 630
 631         parent = chain->parent;
 632
 633         /*
 634          * WARNING! chain's spin lock is still held here, and other spinlocks
 635          *          will be acquired and released in the code below.  We
 636          *          cannot be making fancy procedure calls!
 637          */
 638
 639         /*
 640          * We can cache the chain if it is associated with a pmp
 641          * and not flagged as being destroyed or requesting a full
 642          * release.  In this situation the chain is not removed
 643          * from its parent, i.e. it can still be looked up.
 644          *
 645          * We intentionally do not cache DATA chains because these
 646          * were likely used to load data into the logical buffer cache
 647          * and will not be accessed again for some time.
 648          */
 649         if ((chain->flags &
 650              (HAMMER2_CHAIN_DESTROY | HAMMER2_CHAIN_RELEASE)) == 0 &&
 651             chain->pmp &&
 652             chain->bref.type != HAMMER2_BREF_TYPE_DATA) {
 653                 if (parent)
 654                         hammer2_spin_ex(&parent->core.spin);
 655                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 656                         /*
 657                          * 1->0 transition failed, retry.  Do not drop
 658                          * the chain's data yet!
 659                          */
 660                         if (parent)
 661                                 hammer2_spin_unex(&parent->core.spin);
 662                         hammer2_spin_unex(&chain->core.spin);
 663                         hammer2_mtx_unlock(&chain->lock);
 664
 665                         return(chain);
 666                 }
 667
 668                 /*
 669                  * Success
 670                  */
 671                 hammer2_chain_assert_no_data(chain);
 672
 673                 /*
 674                  * Make sure we are on the LRU list, clean up excessive
 675                  * LRU entries.  We can only really drop one but there might
 676                  * be other entries that we can remove from the lru_list
 677                  * without dropping.
 678                  *
 679                  * NOTE: HAMMER2_CHAIN_ONLRU may only be safely set when
 680                  *       chain->core.spin AND pmp->lru_spin are held, but
 681                  *       can be safely cleared only holding pmp->lru_spin.
 682                  */
 683                 if ((chain->flags & HAMMER2_CHAIN_ONLRU) == 0) {
 684                         hammer2_spin_ex(&pmp->lru_spin);
 685                         if ((chain->flags & HAMMER2_CHAIN_ONLRU) == 0) {
 686                                 atomic_set_int(&chain->flags,
 687                                                HAMMER2_CHAIN_ONLRU);
 688                                 TAILQ_INSERT_TAIL(&pmp->lru_list,
 689                                                   chain, lru_node);
 690                                 atomic_add_int(&pmp->lru_count, 1);
 691                         }
 692                         if (pmp->lru_count < HAMMER2_LRU_LIMIT)
 693                                 depth = 1;      /* disable lru_list flush */
 694                         hammer2_spin_unex(&pmp->lru_spin);
 695                 } else {
 696                         /* disable lru flush */
 697                         depth = 1;
 698                 }
 699
 700                 if (parent) {
 701                         hammer2_spin_unex(&parent->core.spin);
 702                         parent = NULL;  /* safety */
 703                 }
 704                 hammer2_spin_unex(&chain->core.spin);
 705                 hammer2_mtx_unlock(&chain->lock);
 706
 707                 /*
 708                  * lru_list hysteresis (see above for depth overrides).
 709                  * Note that depth also prevents excessive lastdrop recursion.
 710                  */
 711                 if (depth == 0)
 712                         hammer2_chain_lru_flush(pmp);
 713
 714                 return NULL;
 715                 /* NOT REACHED */
 716         }
 717
 718         /*
 719          * Make sure we are not on the LRU list.
 720          */
 721         if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 722                 hammer2_spin_ex(&pmp->lru_spin);
 723                 if (chain->flags & HAMMER2_CHAIN_ONLRU) {
 724                         atomic_add_int(&pmp->lru_count, -1);
 725                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 726                         TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 727                 }
 728                 hammer2_spin_unex(&pmp->lru_spin);
 729         }
 730
 731         /*
 732          * Spinlock the parent and try to drop the last ref on chain.
 733          * On success determine if we should dispose of the chain
 734          * (remove the chain from its parent, etc).
 735          *
 736          * (normal core locks are top-down recursive but we define
 737          * core spinlocks as bottom-up recursive, so this is safe).
 738          */
 739         if (parent) {
 740                 hammer2_spin_ex(&parent->core.spin);
 741                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 742                         /*
 743                          * 1->0 transition failed, retry.
 744                          */
 745                         hammer2_spin_unex(&parent->core.spin);
 746                         hammer2_spin_unex(&chain->core.spin);
 747                         hammer2_mtx_unlock(&chain->lock);
 748
 749                         return(chain);
 750                 }
 751
 752                 /*
 753                  * 1->0 transition successful, parent spin held to prevent
 754                  * new lookups, chain spinlock held to protect parent field.
 755                  * Remove chain from the parent.
 756                  *
 757                  * If the chain is being removed from the parent's btree but
 758                  * is not bmapped, we have to adjust live_count downward.  If
 759                  * it is bmapped then the blockref is retained in the parent
 760                  * as is its associated live_count.  This case can occur when
 761                  * a chain added to the topology is unable to flush and is
 762                  * then later deleted.
 763                  */
 764                 if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
 765                         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) &&
 766                             (chain->flags & HAMMER2_CHAIN_BMAPPED) == 0) {
 767                                 atomic_add_int(&parent->core.live_count, -1);
 768                         }
 769                         RB_REMOVE(hammer2_chain_tree,
 770                                   &parent->core.rbtree, chain);
 771                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
 772                         --parent->core.chain_count;
 773                         chain->parent = NULL;
 774                 }
 775
 776                 /*
 777                  * If our chain was the last chain in the parent's core the
 778                  * core is now empty and its parent might have to be
 779                  * re-dropped if it has 0 refs.
 780                  */
 781                 if (parent->core.chain_count == 0) {
 782                         rdrop = parent;
 783                         atomic_add_int(&rdrop->refs, 1);
 784                         /*
 785                         if (atomic_cmpset_int(&rdrop->refs, 0, 1) == 0)
 786                                 rdrop = NULL;
 787                         */
 788                 }
 789                 hammer2_spin_unex(&parent->core.spin);
 790                 parent = NULL;  /* safety */
 791                 /* FALL THROUGH */
 792         } else {
 793                 /*
 794                  * No-parent case.
 795                  */
 796                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
 797                         /*
 798                          * 1->0 transition failed, retry.
 799                          */
 800                         hammer2_spin_unex(&parent->core.spin);
 801                         hammer2_spin_unex(&chain->core.spin);
 802                         hammer2_mtx_unlock(&chain->lock);
 803
 804                         return(chain);
 805                 }
 806         }
 807
 808         /*
 809          * Successful 1->0 transition, no parent, no children... no way for
 810          * anyone to ref this chain any more.  We can clean-up and free it.
 811          *
 812          * We still have the core spinlock, and core's chain_count is 0.
 813          * Any parent spinlock is gone.
 814          */
 815         hammer2_spin_unex(&chain->core.spin);
 816         hammer2_chain_assert_no_data(chain);
 817         hammer2_mtx_unlock(&chain->lock);
 818         KKASSERT(RB_EMPTY(&chain->core.rbtree) &&
 819                  chain->core.chain_count == 0);
 820
 821         /*
 822          * All locks are gone, no pointers remain to the chain, finish
 823          * freeing it.
 824          */
 825         KKASSERT((chain->flags & (HAMMER2_CHAIN_UPDATE |
 826                                   HAMMER2_CHAIN_MODIFIED)) == 0);
 827
 828         /*
 829          * Once chain resources are gone we can use the now dead chain
 830          * structure to placehold what might otherwise require a recursive
 831          * drop, because we have potentially two things to drop and can only
 832          * return one directly.
 833          */
 834         if (chain->flags & HAMMER2_CHAIN_ALLOCATED) {
 835                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ALLOCATED);
 836                 chain->hmp = NULL;
 837                 kfree(chain, hmp->mchain);
 838         }
 839
 840         /*
 841          * Possible chaining loop when parent re-drop needed.
 842          */
 843         return(rdrop);
 844 }
 845
 846 /*
 847  * Heuristical flush of the LRU, try to reduce the number of entries
 848  * on the LRU to (HAMMER2_LRU_LIMIT * 2 / 3).  This procedure is called
 849  * only when lru_count exceeds HAMMER2_LRU_LIMIT.
 850  */
 851 static
 852 void
 853 hammer2_chain_lru_flush(hammer2_pfs_t *pmp)
 854 {
 855         hammer2_chain_t *chain;
 856
 857 again:
 858         chain = NULL;
 859         hammer2_spin_ex(&pmp->lru_spin);
 860         while (pmp->lru_count > HAMMER2_LRU_LIMIT * 2 / 3) {
 861                 /*
 862                  * Pick a chain off the lru_list, just recycle it quickly
 863                  * if LRUHINT is set (the chain was ref'd but left on
 864                  * the lru_list, so cycle to the end).
 865                  */
 866                 chain = TAILQ_FIRST(&pmp->lru_list);
 867                 TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
 868
 869                 if (chain->flags & HAMMER2_CHAIN_LRUHINT) {
 870                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_LRUHINT);
 871                         TAILQ_INSERT_TAIL(&pmp->lru_list, chain, lru_node);
 872                         chain = NULL;
 873                         continue;
 874                 }
 875
 876                 /*
 877                  * Ok, we are off the LRU.  We must adjust refs before we
 878                  * can safely clear the ONLRU flag.
 879                  */
 880                 atomic_add_int(&pmp->lru_count, -1);
 881                 if (atomic_cmpset_int(&chain->refs, 0, 1)) {
 882                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 883                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
 884                         break;
 885                 }
 886                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
 887                 chain = NULL;
 888         }
 889         hammer2_spin_unex(&pmp->lru_spin);
 890         if (chain == NULL)
 891                 return;
 892
 893         /*
 894          * If we picked a chain off the lru list we may be able to lastdrop
 895          * it.  Use a depth of 1 to prevent excessive lastdrop recursion.
 896          */
 897         while (chain) {
 898                 u_int refs;
 899
 900                 refs = chain->refs;
 901                 cpu_ccfence();
 902                 KKASSERT(refs > 0);
 903
 904                 if (refs == 1) {
 905                         if (hammer2_mtx_ex_try(&chain->lock) == 0)
 906                                 chain = hammer2_chain_lastdrop(chain, 1);
 907                         /* retry the same chain, or chain from lastdrop */
 908                 } else {
 909                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
 910                                 break;
 911                         /* retry the same chain */
 912                 }
 913                 cpu_pause();
 914         }
 915         goto again;
 916 }
 917
 918 /*
 919  * On last lock release.
 920  */
 921 static hammer2_io_t *
 922 hammer2_chain_drop_data(hammer2_chain_t *chain)
 923 {
 924         hammer2_io_t *dio;
 925
 926         if ((dio = chain->dio) != NULL) {
 927                 chain->dio = NULL;
 928                 chain->data = NULL;
 929         } else {
 930                 switch(chain->bref.type) {
 931                 case HAMMER2_BREF_TYPE_VOLUME:
 932                 case HAMMER2_BREF_TYPE_FREEMAP:
 933                         break;
 934                 default:
 935                         if (chain->data != NULL) {
 936                                 hammer2_spin_unex(&chain->core.spin);
 937                                 panic("chain data not null: "
 938                                       "chain %p bref %016jx.%02x "
 939                                       "refs %d parent %p dio %p data %p",
 940                                       chain, chain->bref.data_off,
 941                                       chain->bref.type, chain->refs,
 942                                       chain->parent,
 943                                       chain->dio, chain->data);
 944                         }
 945                         KKASSERT(chain->data == NULL);
 946                         break;
 947                 }
 948         }
 949         return dio;
 950 }
 951
 952 /*
 953  * Lock a referenced chain element, acquiring its data with I/O if necessary,
 954  * and specify how you would like the data to be resolved.
 955  *
 956  * If an I/O or other fatal error occurs, chain->error will be set to non-zero.
 957  *
 958  * The lock is allowed to recurse, multiple locking ops will aggregate
 959  * the requested resolve types.  Once data is assigned it will not be
 960  * removed until the last unlock.
 961  *
 962  * HAMMER2_RESOLVE_NEVER - Do not resolve the data element.
 963  *                         (typically used to avoid device/logical buffer
 964  *                          aliasing for data)
 965  *
 966  * HAMMER2_RESOLVE_MAYBE - Do not resolve data elements for chains in
 967  *                         the INITIAL-create state (indirect blocks only).
 968  *
 969  *                         Do not resolve data elements for DATA chains.
 970  *                         (typically used to avoid device/logical buffer
 971  *                          aliasing for data)
 972  *
 973  * HAMMER2_RESOLVE_ALWAYS- Always resolve the data element.
 974  *
 975  * HAMMER2_RESOLVE_SHARED- (flag) The chain is locked shared, otherwise
 976  *                         it will be locked exclusive.
 977  *
 978  * HAMMER2_RESOLVE_NONBLOCK- (flag) The chain is locked non-blocking.  If
 979  *                         the lock fails, EAGAIN is returned.
 980  *
 981  * NOTE: Embedded elements (volume header, inodes) are always resolved
 982  *       regardless.
 983  *
 984  * NOTE: Specifying HAMMER2_RESOLVE_ALWAYS on a newly-created non-embedded
 985  *       element will instantiate and zero its buffer, and flush it on
 986  *       release.
 987  *
 988  * NOTE: (data) elements are normally locked RESOLVE_NEVER or RESOLVE_MAYBE
 989  *       so as not to instantiate a device buffer, which could alias against
 990  *       a logical file buffer.  However, if ALWAYS is specified the
 991  *       device buffer will be instantiated anyway.
 992  *
 993  * NOTE: The return value is always 0 unless NONBLOCK is specified, in which
 994  *       case it can be either 0 or EAGAIN.
 995  *
 996  * WARNING! This function blocks on I/O if data needs to be fetched.  This
 997  *          blocking can run concurrent with other compatible lock holders
 998  *          who do not need data returning.  The lock is not upgraded to
 999  *          exclusive during a data fetch, a separate bit is used to
1000  *          interlock I/O.  However, an exclusive lock holder can still count
1001  *          on being interlocked against an I/O fetch managed by a shared
1002  *          lock holder.
1003  */
1004 int
1005 hammer2_chain_lock(hammer2_chain_t *chain, int how)
1006 {
1007         KKASSERT(chain->refs > 0);
1008
1009         if (how & HAMMER2_RESOLVE_NONBLOCK) {
1010                 /*
1011                  * We still have to bump lockcnt before acquiring the lock,
1012                  * even for non-blocking operation, because the unlock code
1013                  * live-loops on lockcnt == 1 when dropping the last lock.
1014                  *
1015                  * If the non-blocking operation fails we have to use an
1016                  * unhold sequence to undo the mess.
1017                  *
1018                  * NOTE: LOCKAGAIN must always succeed without blocking,
1019                  *       even if NONBLOCK is specified.
1020                  */
1021                 atomic_add_int(&chain->lockcnt, 1);
1022                 if (how & HAMMER2_RESOLVE_SHARED) {
1023                         if (how & HAMMER2_RESOLVE_LOCKAGAIN) {
1024                                 hammer2_mtx_sh_again(&chain->lock);
1025                         } else {
1026                                 if (hammer2_mtx_sh_try(&chain->lock) != 0) {
1027                                         hammer2_chain_unhold(chain);
1028                                         return EAGAIN;
1029                                 }
1030                         }
1031                 } else {
1032                         if (hammer2_mtx_ex_try(&chain->lock) != 0) {
1033                                 hammer2_chain_unhold(chain);
1034                                 return EAGAIN;
1035                         }
1036                 }
1037                 ++curthread->td_tracker;
1038         } else {
1039                 /*
1040                  * Get the appropriate lock.  If LOCKAGAIN is flagged with
1041                  * SHARED the caller expects a shared lock to already be
1042                  * present and we are giving it another ref.  This case must
1043                  * importantly not block if there is a pending exclusive lock
1044                  * request.
1045                  */
1046                 atomic_add_int(&chain->lockcnt, 1);
1047                 if (how & HAMMER2_RESOLVE_SHARED) {
1048                         if (how & HAMMER2_RESOLVE_LOCKAGAIN) {
1049                                 hammer2_mtx_sh_again(&chain->lock);
1050                         } else {
1051                                 hammer2_mtx_sh(&chain->lock);
1052                         }
1053                 } else {
1054                         hammer2_mtx_ex(&chain->lock);
1055                 }
1056                 ++curthread->td_tracker;
1057         }
1058
1059         /*
1060          * If we already have a valid data pointer make sure the data is
1061          * synchronized to the current cpu, and then no further action is
1062          * necessary.
1063          */
1064         if (chain->data) {
1065                 if (chain->dio)
1066                         hammer2_io_bkvasync(chain->dio);
1067                 return 0;
1068         }
1069
1070         /*
1071          * Do we have to resolve the data?  This is generally only
1072          * applicable to HAMMER2_BREF_TYPE_DATA which is special-cased.
1073          * Other BREF types expects the data to be there.
1074          */
1075         switch(how & HAMMER2_RESOLVE_MASK) {
1076         case HAMMER2_RESOLVE_NEVER:
1077                 return 0;
1078         case HAMMER2_RESOLVE_MAYBE:
1079                 if (chain->flags & HAMMER2_CHAIN_INITIAL)
1080                         return 0;
1081                 if (chain->bref.type == HAMMER2_BREF_TYPE_DATA)
1082                         return 0;
1083 #if 0
1084                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE)
1085                         return 0;
1086                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF)
1087                         return 0;
1088 #endif
1089                 /* fall through */
1090         case HAMMER2_RESOLVE_ALWAYS:
1091         default:
1092                 break;
1093         }
1094
1095         /*
1096          * Caller requires data
1097          */
1098         hammer2_chain_load_data(chain);
1099
1100         return 0;
1101 }
1102
1103 /*
1104  * Lock the chain, retain the hold, and drop the data persistence count.
1105  * The data should remain valid because we never transitioned lockcnt
1106  * through 0.
1107  */
1108 void
1109 hammer2_chain_lock_unhold(hammer2_chain_t *chain, int how)
1110 {
1111         hammer2_chain_lock(chain, how);
1112         atomic_add_int(&chain->lockcnt, -1);
1113 }
1114
1115 #if 0
1116 /*
1117  * Downgrade an exclusive chain lock to a shared chain lock.
1118  *
1119  * NOTE: There is no upgrade equivalent due to the ease of
1120  *       deadlocks in that direction.
1121  */
1122 void
1123 hammer2_chain_lock_downgrade(hammer2_chain_t *chain)
1124 {
1125         hammer2_mtx_downgrade(&chain->lock);
1126 }
1127 #endif
1128
1129 /*
1130  * Issue I/O and install chain->data.  Caller must hold a chain lock, lock
1131  * may be of any type.
1132  *
1133  * Once chain->data is set it cannot be disposed of until all locks are
1134  * released.
1135  *
1136  * Make sure the data is synchronized to the current cpu.
1137  */
1138 void
1139 hammer2_chain_load_data(hammer2_chain_t *chain)
1140 {
1141         hammer2_blockref_t *bref;
1142         hammer2_dev_t *hmp;
1143         hammer2_io_t *dio;
1144         char *bdata;
1145         int error;
1146
1147         /*
1148          * Degenerate case, data already present, or chain has no media
1149          * reference to load.
1150          */
1151         KKASSERT(chain->lock.mtx_lock & MTX_MASK);
1152         if (chain->data) {
1153                 if (chain->dio)
1154                         hammer2_io_bkvasync(chain->dio);
1155                 return;
1156         }
1157         if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0)
1158                 return;
1159
1160         hmp = chain->hmp;
1161         KKASSERT(hmp != NULL);
1162
1163         /*
1164          * Gain the IOINPROG bit, interlocked block.
1165          */
1166         for (;;) {
1167                 u_int oflags;
1168                 u_int nflags;
1169
1170                 oflags = chain->flags;
1171                 cpu_ccfence();
1172                 if (oflags & HAMMER2_CHAIN_IOINPROG) {
1173                         nflags = oflags | HAMMER2_CHAIN_IOSIGNAL;
1174                         tsleep_interlock(&chain->flags, 0);
1175                         if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1176                                 tsleep(&chain->flags, PINTERLOCKED,
1177                                         "h2iocw", 0);
1178                         }
1179                         /* retry */
1180                 } else {
1181                         nflags = oflags | HAMMER2_CHAIN_IOINPROG;
1182                         if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1183                                 break;
1184                         }
1185                         /* retry */
1186                 }
1187         }
1188
1189         /*
1190          * We own CHAIN_IOINPROG
1191          *
1192          * Degenerate case if we raced another load.
1193          */
1194         if (chain->data) {
1195                 if (chain->dio)
1196                         hammer2_io_bkvasync(chain->dio);
1197                 goto done;
1198         }
1199
1200         /*
1201          * We must resolve to a device buffer, either by issuing I/O or
1202          * by creating a zero-fill element.  We do not mark the buffer
1203          * dirty when creating a zero-fill element (the hammer2_chain_modify()
1204          * API must still be used to do that).
1205          *
1206          * The device buffer is variable-sized in powers of 2 down
1207          * to HAMMER2_MIN_ALLOC (typically 1K).  A 64K physical storage
1208          * chunk always contains buffers of the same size. (XXX)
1209          *
1210          * The minimum physical IO size may be larger than the variable
1211          * block size.
1212          */
1213         bref = &chain->bref;
1214
1215         /*
1216          * The getblk() optimization can only be used on newly created
1217          * elements if the physical block size matches the request.
1218          */
1219         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1220                 error = hammer2_io_new(hmp, bref->type,
1221                                        bref->data_off, chain->bytes,
1222                                        &chain->dio);
1223         } else {
1224                 error = hammer2_io_bread(hmp, bref->type,
1225                                          bref->data_off, chain->bytes,
1226                                          &chain->dio);
1227                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1228         }
1229         if (error) {
1230                 chain->error = HAMMER2_ERROR_EIO;
1231                 kprintf("hammer2_chain_lock: I/O error %016jx: %d\n",
1232                         (intmax_t)bref->data_off, error);
1233                 hammer2_io_bqrelse(&chain->dio);
1234                 goto done;
1235         }
1236         chain->error = 0;
1237
1238         /*
1239          * This isn't perfect and can be ignored on OSs which do not have
1240          * an indication as to whether a buffer is coming from cache or
1241          * if I/O was actually issued for the read.  TESTEDGOOD will work
1242          * pretty well without the B_IOISSUED logic because chains are
1243          * cached, but in that situation (without B_IOISSUED) it will not
1244          * detect whether a re-read via I/O is corrupted verses the original
1245          * read.
1246          *
1247          * We can't re-run the CRC on every fresh lock.  That would be
1248          * insanely expensive.
1249          *
1250          * If the underlying kernel buffer covers the entire chain we can
1251          * use the B_IOISSUED indication to determine if we have to re-run
1252          * the CRC on chain data for chains that managed to stay cached
1253          * across the kernel disposal of the original buffer.
1254          */
1255         if ((dio = chain->dio) != NULL && dio->bp) {
1256                 struct buf *bp = dio->bp;
1257
1258                 if (dio->psize == chain->bytes &&
1259                     (bp->b_flags & B_IOISSUED)) {
1260                         atomic_clear_int(&chain->flags,
1261                                          HAMMER2_CHAIN_TESTEDGOOD);
1262                         bp->b_flags &= ~B_IOISSUED;
1263                 }
1264         }
1265
1266         /*
1267          * NOTE: A locked chain's data cannot be modified without first
1268          *       calling hammer2_chain_modify().
1269          */
1270
1271         /*
1272          * Clear INITIAL.  In this case we used io_new() and the buffer has
1273          * been zero'd and marked dirty.
1274          *
1275          * NOTE: hammer2_io_data() call issues bkvasync()
1276          */
1277         bdata = hammer2_io_data(chain->dio, chain->bref.data_off);
1278
1279         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1280                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1281                 chain->bref.flags |= HAMMER2_BREF_FLAG_ZERO;
1282         } else if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
1283                 /*
1284                  * check data not currently synchronized due to
1285                  * modification.  XXX assumes data stays in the buffer
1286                  * cache, which might not be true (need biodep on flush
1287                  * to calculate crc?  or simple crc?).
1288                  */
1289         } else if ((chain->flags & HAMMER2_CHAIN_TESTEDGOOD) == 0) {
1290                 if (hammer2_chain_testcheck(chain, bdata) == 0) {
1291                         chain->error = HAMMER2_ERROR_CHECK;
1292                 } else {
1293                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_TESTEDGOOD);
1294                 }
1295         }
1296
1297         /*
1298          * Setup the data pointer, either pointing it to an embedded data
1299          * structure and copying the data from the buffer, or pointing it
1300          * into the buffer.
1301          *
1302          * The buffer is not retained when copying to an embedded data
1303          * structure in order to avoid potential deadlocks or recursions
1304          * on the same physical buffer.
1305          *
1306          * WARNING! Other threads can start using the data the instant we
1307          *          set chain->data non-NULL.
1308          */
1309         switch (bref->type) {
1310         case HAMMER2_BREF_TYPE_VOLUME:
1311         case HAMMER2_BREF_TYPE_FREEMAP:
1312                 /*
1313                  * Copy data from bp to embedded buffer
1314                  */
1315                 panic("hammer2_chain_load_data: unresolved volume header");
1316                 break;
1317         case HAMMER2_BREF_TYPE_DIRENT:
1318                 KKASSERT(chain->bytes != 0);
1319                 /* fall through */
1320         case HAMMER2_BREF_TYPE_INODE:
1321         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1322         case HAMMER2_BREF_TYPE_INDIRECT:
1323         case HAMMER2_BREF_TYPE_DATA:
1324         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1325         default:
1326                 /*
1327                  * Point data at the device buffer and leave dio intact.
1328                  */
1329                 chain->data = (void *)bdata;
1330                 break;
1331         }
1332
1333         /*
1334          * Release HAMMER2_CHAIN_IOINPROG and signal waiters if requested.
1335          */
1336 done:
1337         for (;;) {
1338                 u_int oflags;
1339                 u_int nflags;
1340
1341                 oflags = chain->flags;
1342                 nflags = oflags & ~(HAMMER2_CHAIN_IOINPROG |
1343                                     HAMMER2_CHAIN_IOSIGNAL);
1344                 KKASSERT(oflags & HAMMER2_CHAIN_IOINPROG);
1345                 if (atomic_cmpset_int(&chain->flags, oflags, nflags)) {
1346                         if (oflags & HAMMER2_CHAIN_IOSIGNAL)
1347                                 wakeup(&chain->flags);
1348                         break;
1349                 }
1350         }
1351 }
1352
1353 /*
1354  * Unlock and deref a chain element.
1355  *
1356  * Remember that the presence of children under chain prevent the chain's
1357  * destruction but do not add additional references, so the dio will still
1358  * be dropped.
1359  */
1360 void
1361 hammer2_chain_unlock(hammer2_chain_t *chain)
1362 {
1363         hammer2_io_t *dio;
1364         u_int lockcnt;
1365         int iter = 0;
1366
1367         --curthread->td_tracker;
1368
1369         /*
1370          * If multiple locks are present (or being attempted) on this
1371          * particular chain we can just unlock, drop refs, and return.
1372          *
1373          * Otherwise fall-through on the 1->0 transition.
1374          */
1375         for (;;) {
1376                 lockcnt = chain->lockcnt;
1377                 KKASSERT(lockcnt > 0);
1378                 cpu_ccfence();
1379                 if (lockcnt > 1) {
1380                         if (atomic_cmpset_int(&chain->lockcnt,
1381                                               lockcnt, lockcnt - 1)) {
1382                                 hammer2_mtx_unlock(&chain->lock);
1383                                 return;
1384                         }
1385                 } else if (hammer2_mtx_upgrade_try(&chain->lock) == 0) {
1386                         /* while holding the mutex exclusively */
1387                         if (atomic_cmpset_int(&chain->lockcnt, 1, 0))
1388                                 break;
1389                 } else {
1390                         /*
1391                          * This situation can easily occur on SMP due to
1392                          * the gap inbetween the 1->0 transition and the
1393                          * final unlock.  We cannot safely block on the
1394                          * mutex because lockcnt might go above 1.
1395                          *
1396                          * XXX Sleep for one tick if it takes too long.
1397                          */
1398                         if (++iter > 1000) {
1399                                 if (iter > 1000 + hz) {
1400                                         kprintf("hammer2: h2race2 %p\n", chain);
1401                                         iter = 1000;
1402                                 }
1403                                 tsleep(&iter, 0, "h2race2", 1);
1404                         }
1405                         cpu_pause();
1406                 }
1407                 /* retry */
1408         }
1409
1410         /*
1411          * Last unlock / mutex upgraded to exclusive.  Drop the data
1412          * reference.
1413          */
1414         dio = hammer2_chain_drop_data(chain);
1415         if (dio)
1416                 hammer2_io_bqrelse(&dio);
1417         hammer2_mtx_unlock(&chain->lock);
1418 }
1419
1420 /*
1421  * Unlock and hold chain data intact
1422  */
1423 void
1424 hammer2_chain_unlock_hold(hammer2_chain_t *chain)
1425 {
1426         atomic_add_int(&chain->lockcnt, 1);
1427         hammer2_chain_unlock(chain);
1428 }
1429
1430 /*
1431  * Helper to obtain the blockref[] array base and count for a chain.
1432  *
1433  * XXX Not widely used yet, various use cases need to be validated and
1434  *     converted to use this function.
1435  */
1436 static
1437 hammer2_blockref_t *
1438 hammer2_chain_base_and_count(hammer2_chain_t *parent, int *countp)
1439 {
1440         hammer2_blockref_t *base;
1441         int count;
1442
1443         if (parent->flags & HAMMER2_CHAIN_INITIAL) {
1444                 base = NULL;
1445
1446                 switch(parent->bref.type) {
1447                 case HAMMER2_BREF_TYPE_INODE:
1448                         count = HAMMER2_SET_COUNT;
1449                         break;
1450                 case HAMMER2_BREF_TYPE_INDIRECT:
1451                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1452                         count = parent->bytes / sizeof(hammer2_blockref_t);
1453                         break;
1454                 case HAMMER2_BREF_TYPE_VOLUME:
1455                         count = HAMMER2_SET_COUNT;
1456                         break;
1457                 case HAMMER2_BREF_TYPE_FREEMAP:
1458                         count = HAMMER2_SET_COUNT;
1459                         break;
1460                 default:
1461                         panic("hammer2_chain_base_and_count: "
1462                               "unrecognized blockref type: %d",
1463                               parent->bref.type);
1464                         count = 0;
1465                         break;
1466                 }
1467         } else {
1468                 switch(parent->bref.type) {
1469                 case HAMMER2_BREF_TYPE_INODE:
1470                         base = &parent->data->ipdata.u.blockset.blockref[0];
1471                         count = HAMMER2_SET_COUNT;
1472                         break;
1473                 case HAMMER2_BREF_TYPE_INDIRECT:
1474                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1475                         base = &parent->data->npdata[0];
1476                         count = parent->bytes / sizeof(hammer2_blockref_t);
1477                         break;
1478                 case HAMMER2_BREF_TYPE_VOLUME:
1479                         base = &parent->data->voldata.
1480                                         sroot_blockset.blockref[0];
1481                         count = HAMMER2_SET_COUNT;
1482                         break;
1483                 case HAMMER2_BREF_TYPE_FREEMAP:
1484                         base = &parent->data->blkset.blockref[0];
1485                         count = HAMMER2_SET_COUNT;
1486                         break;
1487                 default:
1488                         panic("hammer2_chain_base_and_count: "
1489                               "unrecognized blockref type: %d",
1490                               parent->bref.type);
1491                         count = 0;
1492                         break;
1493                 }
1494         }
1495         *countp = count;
1496
1497         return base;
1498 }
1499
1500 /*
1501  * This counts the number of live blockrefs in a block array and
1502  * also calculates the point at which all remaining blockrefs are empty.
1503  * This routine can only be called on a live chain.
1504  *
1505  * Caller holds the chain locked, but possibly with a shared lock.  We
1506  * must use an exclusive spinlock to prevent corruption.
1507  *
1508  * NOTE: Flag is not set until after the count is complete, allowing
1509  *       callers to test the flag without holding the spinlock.
1510  *
1511  * NOTE: If base is NULL the related chain is still in the INITIAL
1512  *       state and there are no blockrefs to count.
1513  *
1514  * NOTE: live_count may already have some counts accumulated due to
1515  *       creation and deletion and could even be initially negative.
1516  */
1517 void
1518 hammer2_chain_countbrefs(hammer2_chain_t *chain,
1519                          hammer2_blockref_t *base, int count)
1520 {
1521         hammer2_spin_ex(&chain->core.spin);
1522         if ((chain->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0) {
1523                 if (base) {
1524                         while (--count >= 0) {
1525                                 if (base[count].type != HAMMER2_BREF_TYPE_EMPTY)
1526                                         break;
1527                         }
1528                         chain->core.live_zero = count + 1;
1529                         while (count >= 0) {
1530                                 if (base[count].type != HAMMER2_BREF_TYPE_EMPTY)
1531                                         atomic_add_int(&chain->core.live_count,
1532                                                        1);
1533                                 --count;
1534                         }
1535                 } else {
1536                         chain->core.live_zero = 0;
1537                 }
1538                 /* else do not modify live_count */
1539                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_COUNTEDBREFS);
1540         }
1541         hammer2_spin_unex(&chain->core.spin);
1542 }
1543
1544 /*
1545  * Resize the chain's physical storage allocation in-place.  This function does
1546  * not usually adjust the data pointer and must be followed by (typically) a
1547  * hammer2_chain_modify() call to copy any old data over and adjust the
1548  * data pointer.
1549  *
1550  * Chains can be resized smaller without reallocating the storage.  Resizing
1551  * larger will reallocate the storage.  Excess or prior storage is reclaimed
1552  * asynchronously at a later time.
1553  *
1554  * An nradix value of 0 is special-cased to mean that the storage should
1555  * be disassociated, that is the chain is being resized to 0 bytes (not 1
1556  * byte).
1557  *
1558  * Must be passed an exclusively locked parent and chain.
1559  *
1560  * This function is mostly used with DATA blocks locked RESOLVE_NEVER in order
1561  * to avoid instantiating a device buffer that conflicts with the vnode data
1562  * buffer.  However, because H2 can compress or encrypt data, the chain may
1563  * have a dio assigned to it in those situations, and they do not conflict.
1564  *
1565  * XXX return error if cannot resize.
1566  */
1567 int
1568 hammer2_chain_resize(hammer2_chain_t *chain,
1569                      hammer2_tid_t mtid, hammer2_off_t dedup_off,
1570                      int nradix, int flags)
1571 {
1572         hammer2_dev_t *hmp;
1573         size_t obytes;
1574         size_t nbytes;
1575         int error;
1576
1577         hmp = chain->hmp;
1578
1579         /*
1580          * Only data and indirect blocks can be resized for now.
1581          * (The volu root, inodes, and freemap elements use a fixed size).
1582          */
1583         KKASSERT(chain != &hmp->vchain);
1584         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1585                  chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
1586                  chain->bref.type == HAMMER2_BREF_TYPE_DIRENT);
1587
1588         /*
1589          * Nothing to do if the element is already the proper size
1590          */
1591         obytes = chain->bytes;
1592         nbytes = (nradix) ? (1U << nradix) : 0;
1593         if (obytes == nbytes)
1594                 return (chain->error);
1595
1596         /*
1597          * Make sure the old data is instantiated so we can copy it.  If this
1598          * is a data block, the device data may be superfluous since the data
1599          * might be in a logical block, but compressed or encrypted data is
1600          * another matter.
1601          *
1602          * NOTE: The modify will set BMAPUPD for us if BMAPPED is set.
1603          */
1604         error = hammer2_chain_modify(chain, mtid, dedup_off, 0);
1605         if (error)
1606                 return error;
1607
1608         /*
1609          * Relocate the block, even if making it smaller (because different
1610          * block sizes may be in different regions).
1611          *
1612          * NOTE: Operation does not copy the data and may only be used
1613          *        to resize data blocks in-place, or directory entry blocks
1614          *        which are about to be modified in some manner.
1615          */
1616         error = hammer2_freemap_alloc(chain, nbytes);
1617         if (error)
1618                 return error;
1619
1620         chain->bytes = nbytes;
1621
1622         /*
1623          * We don't want the followup chain_modify() to try to copy data
1624          * from the old (wrong-sized) buffer.  It won't know how much to
1625          * copy.  This case should only occur during writes when the
1626          * originator already has the data to write in-hand.
1627          */
1628         if (chain->dio) {
1629                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1630                          chain->bref.type == HAMMER2_BREF_TYPE_DIRENT);
1631                 hammer2_io_brelse(&chain->dio);
1632                 chain->data = NULL;
1633         }
1634         return (chain->error);
1635 }
1636
1637 /*
1638  * Set the chain modified so its data can be changed by the caller, or
1639  * install deduplicated data.  The caller must call this routine for each
1640  * set of modifications it makes, even if the chain is already flagged
1641  * MODIFIED.
1642  *
1643  * Sets bref.modify_tid to mtid only if mtid != 0.  Note that bref.modify_tid
1644  * is a CLC (cluster level change) field and is not updated by parent
1645  * propagation during a flush.
1646  *
1647  * Returns an appropriate HAMMER2_ERROR_* code, which will generally reflect
1648  * chain->error except for HAMMER2_ERROR_ENOSPC.  If the allocation fails
1649  * due to no space available, HAMMER2_ERROR_ENOSPC is returned and the chain
1650  * remains unmodified with its old data ref intact and chain->error
1651  * unchanged.
1652  *
1653  *                               Dedup Handling
1654  *
1655  * If the DEDUPABLE flag is set in the chain the storage must be reallocated
1656  * even if the chain is still flagged MODIFIED.  In this case the chain's
1657  * DEDUPABLE flag will be cleared once the new storage has been assigned.
1658  *
1659  * If the caller passes a non-zero dedup_off we will use it to assign the
1660  * new storage.  The MODIFIED flag will be *CLEARED* in this case, and
1661  * DEDUPABLE will be set (NOTE: the UPDATE flag is always set).  The caller
1662  * must not modify the data content upon return.
1663  */
1664 int
1665 hammer2_chain_modify(hammer2_chain_t *chain, hammer2_tid_t mtid,
1666                      hammer2_off_t dedup_off, int flags)
1667 {
1668         hammer2_blockref_t obref;
1669         hammer2_dev_t *hmp;
1670         hammer2_io_t *dio;
1671         int error;
1672         int wasinitial;
1673         int setmodified;
1674         int setupdate;
1675         int newmod;
1676         char *bdata;
1677
1678         hmp = chain->hmp;
1679         obref = chain->bref;
1680         KKASSERT((chain->flags & HAMMER2_CHAIN_FICTITIOUS) == 0);
1681         KKASSERT(chain->lock.mtx_lock & MTX_EXCLUSIVE);
1682
1683         /*
1684          * Data is not optional for freemap chains (we must always be sure
1685          * to copy the data on COW storage allocations).
1686          */
1687         if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
1688             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
1689                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) ||
1690                          (flags & HAMMER2_MODIFY_OPTDATA) == 0);
1691         }
1692
1693         /*
1694          * Data must be resolved if already assigned, unless explicitly
1695          * flagged otherwise.  If we cannot safety load the data the
1696          * modification fails and we return early.
1697          */
1698         if (chain->data == NULL && chain->bytes != 0 &&
1699             (flags & HAMMER2_MODIFY_OPTDATA) == 0 &&
1700             (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
1701                 hammer2_chain_load_data(chain);
1702                 if (chain->error)
1703                         return (chain->error);
1704         }
1705         error = 0;
1706
1707         /*
1708          * Set MODIFIED to indicate that the chain has been modified.  A new
1709          * allocation is required when modifying a chain.
1710          *
1711          * Set UPDATE to ensure that the blockref is updated in the parent.
1712          *
1713          * If MODIFIED is already set determine if we can reuse the assigned
1714          * data block or if we need a new data block.
1715          */
1716         if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0) {
1717                 /*
1718                  * Must set modified bit.
1719                  */
1720                 atomic_add_long(&hammer2_count_modified_chains, 1);
1721                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1722                 hammer2_pfs_memory_inc(chain->pmp);  /* can be NULL */
1723                 setmodified = 1;
1724
1725                 /*
1726                  * We may be able to avoid a copy-on-write if the chain's
1727                  * check mode is set to NONE and the chain's current
1728                  * modify_tid is beyond the last explicit snapshot tid.
1729                  *
1730                  * This implements HAMMER2's overwrite-in-place feature.
1731                  *
1732                  * NOTE! This data-block cannot be used as a de-duplication
1733                  *       source when the check mode is set to NONE.
1734                  */
1735                 if ((chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
1736                      chain->bref.type == HAMMER2_BREF_TYPE_DIRENT) &&
1737                     (chain->flags & HAMMER2_CHAIN_INITIAL) == 0 &&
1738                     (chain->flags & HAMMER2_CHAIN_DEDUPABLE) == 0 &&
1739                     HAMMER2_DEC_CHECK(chain->bref.methods) ==
1740                      HAMMER2_CHECK_NONE &&
1741                     chain->pmp &&
1742                     chain->bref.modify_tid >
1743                      chain->pmp->iroot->meta.pfs_lsnap_tid) {
1744                         /*
1745                          * Sector overwrite allowed.
1746                          */
1747                         newmod = 0;
1748                 } else {
1749                         /*
1750                          * Sector overwrite not allowed, must copy-on-write.
1751                          */
1752                         newmod = 1;
1753                 }
1754         } else if (chain->flags & HAMMER2_CHAIN_DEDUPABLE) {
1755                 /*
1756                  * If the modified chain was registered for dedup we need
1757                  * a new allocation.  This only happens for delayed-flush
1758                  * chains (i.e. which run through the front-end buffer
1759                  * cache).
1760                  */
1761                 newmod = 1;
1762                 setmodified = 0;
1763         } else {
1764                 /*
1765                  * Already flagged modified, no new allocation is needed.
1766                  */
1767                 newmod = 0;
1768                 setmodified = 0;
1769         }
1770
1771         /*
1772          * Flag parent update required.
1773          */
1774         if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0) {
1775                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1776                 setupdate = 1;
1777         } else {
1778                 setupdate = 0;
1779         }
1780
1781         /*
1782          * The XOP code returns held but unlocked focus chains.  This
1783          * prevents the chain from being destroyed but does not prevent
1784          * it from being modified.  diolk is used to interlock modifications
1785          * against XOP frontend accesses to the focus.
1786          *
1787          * This allows us to theoretically avoid deadlocking the frontend
1788          * if one of the backends lock up by not formally locking the
1789          * focused chain in the frontend.  In addition, the synchronization
1790          * code relies on this mechanism to avoid deadlocking concurrent
1791          * synchronization threads.
1792          */
1793         lockmgr(&chain->diolk, LK_EXCLUSIVE);
1794
1795         /*
1796          * The modification or re-modification requires an allocation and
1797          * possible COW.  If an error occurs, the previous content and data
1798          * reference is retained and the modification fails.
1799          *
1800          * If dedup_off is non-zero, the caller is requesting a deduplication
1801          * rather than a modification.  The MODIFIED bit is not set and the
1802          * data offset is set to the deduplication offset.  The data cannot
1803          * be modified.
1804          *
1805          * NOTE: The dedup offset is allowed to be in a partially free state
1806          *       and we must be sure to reset it to a fully allocated state
1807          *       to force two bulkfree passes to free it again.
1808          *
1809          * NOTE: Only applicable when chain->bytes != 0.
1810          *
1811          * XXX can a chain already be marked MODIFIED without a data
1812          * assignment?  If not, assert here instead of testing the case.
1813          */
1814         if (chain != &hmp->vchain && chain != &hmp->fchain &&
1815             chain->bytes) {
1816                 if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0 ||
1817                      newmod
1818                 ) {
1819                         /*
1820                          * NOTE: We do not have to remove the dedup
1821                          *       registration because the area is still
1822                          *       allocated and the underlying DIO will
1823                          *       still be flushed.
1824                          */
1825                         if (dedup_off) {
1826                                 chain->bref.data_off = dedup_off;
1827                                 chain->bytes = 1 << (dedup_off &
1828                                                      HAMMER2_OFF_MASK_RADIX);
1829                                 chain->error = 0;
1830                                 atomic_clear_int(&chain->flags,
1831                                                  HAMMER2_CHAIN_MODIFIED);
1832                                 atomic_add_long(&hammer2_count_modified_chains,
1833                                                 -1);
1834                                 if (chain->pmp)
1835                                         hammer2_pfs_memory_wakeup(chain->pmp);
1836                                 hammer2_freemap_adjust(hmp, &chain->bref,
1837                                                 HAMMER2_FREEMAP_DORECOVER);
1838                                 atomic_set_int(&chain->flags,
1839                                                 HAMMER2_CHAIN_DEDUPABLE);
1840                         } else {
1841                                 error = hammer2_freemap_alloc(chain,
1842                                                               chain->bytes);
1843                                 atomic_clear_int(&chain->flags,
1844                                                 HAMMER2_CHAIN_DEDUPABLE);
1845                         }
1846                 }
1847         }
1848
1849         /*
1850          * Stop here if error.  We have to undo any flag bits we might
1851          * have set above.
1852          */
1853         if (error) {
1854                 if (setmodified) {
1855                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1856                         atomic_add_long(&hammer2_count_modified_chains, -1);
1857                         if (chain->pmp)
1858                                 hammer2_pfs_memory_wakeup(chain->pmp);
1859                 }
1860                 if (setupdate) {
1861                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1862                 }
1863                 lockmgr(&chain->diolk, LK_RELEASE);
1864
1865                 return error;
1866         }
1867
1868         /*
1869          * Update mirror_tid and modify_tid.  modify_tid is only updated
1870          * if not passed as zero (during flushes, parent propagation passes
1871          * the value 0).
1872          *
1873          * NOTE: chain->pmp could be the device spmp.
1874          */
1875         chain->bref.mirror_tid = hmp->voldata.mirror_tid + 1;
1876         if (mtid)
1877                 chain->bref.modify_tid = mtid;
1878
1879         /*
1880          * Set BMAPUPD to tell the flush code that an existing blockmap entry
1881          * requires updating as well as to tell the delete code that the
1882          * chain's blockref might not exactly match (in terms of physical size
1883          * or block offset) the one in the parent's blocktable.  The base key
1884          * of course will still match.
1885          */
1886         if (chain->flags & HAMMER2_CHAIN_BMAPPED)
1887                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPUPD);
1888
1889         /*
1890          * Short-cut data blocks which the caller does not need an actual
1891          * data reference to (aka OPTDATA), as long as the chain does not
1892          * already have a data pointer to the data.  This generally means
1893          * that the modifications are being done via the logical buffer cache.
1894          * The INITIAL flag relates only to the device data buffer and thus
1895          * remains unchange in this situation.
1896          *
1897          * This code also handles bytes == 0 (most dirents).
1898          */
1899         if (chain->bref.type == HAMMER2_BREF_TYPE_DATA &&
1900             (flags & HAMMER2_MODIFY_OPTDATA) &&
1901             chain->data == NULL) {
1902                 KKASSERT(chain->dio == NULL);
1903                 goto skip2;
1904         }
1905
1906         /*
1907          * Clearing the INITIAL flag (for indirect blocks) indicates that
1908          * we've processed the uninitialized storage allocation.
1909          *
1910          * If this flag is already clear we are likely in a copy-on-write
1911          * situation but we have to be sure NOT to bzero the storage if
1912          * no data is present.
1913          */
1914         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1915                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1916                 wasinitial = 1;
1917         } else {
1918                 wasinitial = 0;
1919         }
1920
1921         /*
1922          * Instantiate data buffer and possibly execute COW operation
1923          */
1924         switch(chain->bref.type) {
1925         case HAMMER2_BREF_TYPE_VOLUME:
1926         case HAMMER2_BREF_TYPE_FREEMAP:
1927                 /*
1928                  * The data is embedded, no copy-on-write operation is
1929                  * needed.
1930                  */
1931                 KKASSERT(chain->dio == NULL);
1932                 break;
1933         case HAMMER2_BREF_TYPE_DIRENT:
1934                 /*
1935                  * The data might be fully embedded.
1936                  */
1937                 if (chain->bytes == 0) {
1938                         KKASSERT(chain->dio == NULL);
1939                         break;
1940                 }
1941                 /* fall through */
1942         case HAMMER2_BREF_TYPE_INODE:
1943         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1944         case HAMMER2_BREF_TYPE_DATA:
1945         case HAMMER2_BREF_TYPE_INDIRECT:
1946         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1947                 /*
1948                  * Perform the copy-on-write operation
1949                  *
1950                  * zero-fill or copy-on-write depending on whether
1951                  * chain->data exists or not and set the dirty state for
1952                  * the new buffer.  hammer2_io_new() will handle the
1953                  * zero-fill.
1954                  *
1955                  * If a dedup_off was supplied this is an existing block
1956                  * and no COW, copy, or further modification is required.
1957                  */
1958                 KKASSERT(chain != &hmp->vchain && chain != &hmp->fchain);
1959
1960                 if (wasinitial && dedup_off == 0) {
1961                         error = hammer2_io_new(hmp, chain->bref.type,
1962                                                chain->bref.data_off,
1963                                                chain->bytes, &dio);
1964                 } else {
1965                         error = hammer2_io_bread(hmp, chain->bref.type,
1966                                                  chain->bref.data_off,
1967                                                  chain->bytes, &dio);
1968                 }
1969                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1970
1971                 /*
1972                  * If an I/O error occurs make sure callers cannot accidently
1973                  * modify the old buffer's contents and corrupt the filesystem.
1974                  *
1975                  * NOTE: hammer2_io_data() call issues bkvasync()
1976                  */
1977                 if (error) {
1978                         kprintf("hammer2_chain_modify: hmp=%p I/O error\n",
1979                                 hmp);
1980                         chain->error = HAMMER2_ERROR_EIO;
1981                         hammer2_io_brelse(&dio);
1982                         hammer2_io_brelse(&chain->dio);
1983                         chain->data = NULL;
1984                         break;
1985                 }
1986                 chain->error = 0;
1987                 bdata = hammer2_io_data(dio, chain->bref.data_off);
1988
1989                 if (chain->data) {
1990                         /*
1991                          * COW (unless a dedup).
1992                          */
1993                         KKASSERT(chain->dio != NULL);
1994                         if (chain->data != (void *)bdata && dedup_off == 0) {
1995                                 bcopy(chain->data, bdata, chain->bytes);
1996                         }
1997                 } else if (wasinitial == 0) {
1998                         /*
1999                          * We have a problem.  We were asked to COW but
2000                          * we don't have any data to COW with!
2001                          */
2002                         panic("hammer2_chain_modify: having a COW %p\n",
2003                               chain);
2004                 }
2005
2006                 /*
2007                  * Retire the old buffer, replace with the new.  Dirty or
2008                  * redirty the new buffer.
2009                  *
2010                  * WARNING! The system buffer cache may have already flushed
2011                  *          the buffer, so we must be sure to [re]dirty it
2012                  *          for further modification.
2013                  *
2014                  *          If dedup_off was supplied, the caller is not
2015                  *          expected to make any further modification to the
2016                  *          buffer.
2017                  *
2018                  * WARNING! hammer2_get_gdata() assumes dio never transitions
2019                  *          through NULL in order to optimize away unnecessary
2020                  *          diolk operations.
2021                  */
2022                 {
2023                         hammer2_io_t *tio;
2024
2025                         if ((tio = chain->dio) != NULL)
2026                                 hammer2_io_bqrelse(&tio);
2027                         chain->data = (void *)bdata;
2028                         chain->dio = dio;
2029                         if (dedup_off == 0)
2030                                 hammer2_io_setdirty(dio);
2031                 }
2032                 break;
2033         default:
2034                 panic("hammer2_chain_modify: illegal non-embedded type %d",
2035                       chain->bref.type);
2036                 break;
2037
2038         }
2039 skip2:
2040         /*
2041          * setflush on parent indicating that the parent must recurse down
2042          * to us.  Do not call on chain itself which might already have it
2043          * set.
2044          */
2045         if (chain->parent)
2046                 hammer2_chain_setflush(chain->parent);
2047         lockmgr(&chain->diolk, LK_RELEASE);
2048
2049         return (chain->error);
2050 }
2051
2052 /*
2053  * Modify the chain associated with an inode.
2054  */
2055 int
2056 hammer2_chain_modify_ip(hammer2_inode_t *ip, hammer2_chain_t *chain,
2057                         hammer2_tid_t mtid, int flags)
2058 {
2059         int error;
2060
2061         hammer2_inode_modify(ip);
2062         error = hammer2_chain_modify(chain, mtid, 0, flags);
2063
2064         return error;
2065 }
2066
2067 /*
2068  * Volume header data locks
2069  */
2070 void
2071 hammer2_voldata_lock(hammer2_dev_t *hmp)
2072 {
2073         lockmgr(&hmp->vollk, LK_EXCLUSIVE);
2074 }
2075
2076 void
2077 hammer2_voldata_unlock(hammer2_dev_t *hmp)
2078 {
2079         lockmgr(&hmp->vollk, LK_RELEASE);
2080 }
2081
2082 void
2083 hammer2_voldata_modify(hammer2_dev_t *hmp)
2084 {
2085         if ((hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) == 0) {
2086                 atomic_add_long(&hammer2_count_modified_chains, 1);
2087                 atomic_set_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
2088                 hammer2_pfs_memory_inc(hmp->vchain.pmp);
2089         }
2090 }
2091
2092 /*
2093  * This function returns the chain at the nearest key within the specified
2094  * range.  The returned chain will be referenced but not locked.
2095  *
2096  * This function will recurse through chain->rbtree as necessary and will
2097  * return a *key_nextp suitable for iteration.  *key_nextp is only set if
2098  * the iteration value is less than the current value of *key_nextp.
2099  *
2100  * The caller should use (*key_nextp) to calculate the actual range of
2101  * the returned element, which will be (key_beg to *key_nextp - 1), because
2102  * there might be another element which is superior to the returned element
2103  * and overlaps it.
2104  *
2105  * (*key_nextp) can be passed as key_beg in an iteration only while non-NULL
2106  * chains continue to be returned.  On EOF (*key_nextp) may overflow since
2107  * it will wind up being (key_end + 1).
2108  *
2109  * WARNING!  Must be called with child's spinlock held.  Spinlock remains
2110  *           held through the operation.
2111  */
2112 struct hammer2_chain_find_info {
2113         hammer2_chain_t         *best;
2114         hammer2_key_t           key_beg;
2115         hammer2_key_t           key_end;
2116         hammer2_key_t           key_next;
2117 };
2118
2119 static int hammer2_chain_find_cmp(hammer2_chain_t *child, void *data);
2120 static int hammer2_chain_find_callback(hammer2_chain_t *child, void *data);
2121
2122 static
2123 hammer2_chain_t *
2124 hammer2_chain_find(hammer2_chain_t *parent, hammer2_key_t *key_nextp,
2125                           hammer2_key_t key_beg, hammer2_key_t key_end)
2126 {
2127         struct hammer2_chain_find_info info;
2128
2129         info.best = NULL;
2130         info.key_beg = key_beg;
2131         info.key_end = key_end;
2132         info.key_next = *key_nextp;
2133
2134         RB_SCAN(hammer2_chain_tree, &parent->core.rbtree,
2135                 hammer2_chain_find_cmp, hammer2_chain_find_callback,
2136                 &info);
2137         *key_nextp = info.key_next;
2138 #if 0
2139         kprintf("chain_find %p %016jx:%016jx next=%016jx\n",
2140                 parent, key_beg, key_end, *key_nextp);
2141 #endif
2142
2143         return (info.best);
2144 }
2145
2146 static
2147 int
2148 hammer2_chain_find_cmp(hammer2_chain_t *child, void *data)
2149 {
2150         struct hammer2_chain_find_info *info = data;
2151         hammer2_key_t child_beg;
2152         hammer2_key_t child_end;
2153
2154         child_beg = child->bref.key;
2155         child_end = child_beg + ((hammer2_key_t)1 << child->bref.keybits) - 1;
2156
2157         if (child_end < info->key_beg)
2158                 return(-1);
2159         if (child_beg > info->key_end)
2160                 return(1);
2161         return(0);
2162 }
2163
2164 static
2165 int
2166 hammer2_chain_find_callback(hammer2_chain_t *child, void *data)
2167 {
2168         struct hammer2_chain_find_info *info = data;
2169         hammer2_chain_t *best;
2170         hammer2_key_t child_end;
2171
2172         /*
2173          * WARNING! Layerq is scanned forwards, exact matches should keep
2174          *          the existing info->best.
2175          */
2176         if ((best = info->best) == NULL) {
2177                 /*
2178                  * No previous best.  Assign best
2179                  */
2180                 info->best = child;
2181         } else if (best->bref.key <= info->key_beg &&
2182                    child->bref.key <= info->key_beg) {
2183                 /*
2184                  * Illegal overlap.
2185                  */
2186                 KKASSERT(0);
2187                 /*info->best = child;*/
2188         } else if (child->bref.key < best->bref.key) {
2189                 /*
2190                  * Child has a nearer key and best is not flush with key_beg.
2191                  * Set best to child.  Truncate key_next to the old best key.
2192                  */
2193                 info->best = child;
2194                 if (info->key_next > best->bref.key || info->key_next == 0)
2195                         info->key_next = best->bref.key;
2196         } else if (child->bref.key == best->bref.key) {
2197                 /*
2198                  * If our current best is flush with the child then this
2199                  * is an illegal overlap.
2200                  *
2201                  * key_next will automatically be limited to the smaller of
2202                  * the two end-points.
2203                  */
2204                 KKASSERT(0);
2205                 info->best = child;
2206         } else {
2207                 /*
2208                  * Keep the current best but truncate key_next to the child's
2209                  * base.
2210                  *
2211                  * key_next will also automatically be limited to the smaller
2212                  * of the two end-points (probably not necessary for this case
2213                  * but we do it anyway).
2214                  */
2215                 if (info->key_next > child->bref.key || info->key_next == 0)
2216                         info->key_next = child->bref.key;
2217         }
2218
2219         /*
2220          * Always truncate key_next based on child's end-of-range.
2221          */
2222         child_end = child->bref.key + ((hammer2_key_t)1 << child->bref.keybits);
2223         if (child_end && (info->key_next > child_end || info->key_next == 0))
2224                 info->key_next = child_end;
2225
2226         return(0);
2227 }
2228
2229 /*
2230  * Retrieve the specified chain from a media blockref, creating the
2231  * in-memory chain structure which reflects it.  The returned chain is
2232  * held and locked according to (how) (HAMMER2_RESOLVE_*).  The caller must
2233  * handle crc-checks and so forth, and should check chain->error before
2234  * assuming that the data is good.
2235  *
2236  * To handle insertion races pass the INSERT_RACE flag along with the
2237  * generation number of the core.  NULL will be returned if the generation
2238  * number changes before we have a chance to insert the chain.  Insert
2239  * races can occur because the parent might be held shared.
2240  *
2241  * Caller must hold the parent locked shared or exclusive since we may
2242  * need the parent's bref array to find our block.
2243  *
2244  * WARNING! chain->pmp is always set to NULL for any chain representing
2245  *          part of the super-root topology.
2246  */
2247 hammer2_chain_t *
2248 hammer2_chain_get(hammer2_chain_t *parent, int generation,
2249                   hammer2_blockref_t *bref, int how)
2250 {
2251         hammer2_dev_t *hmp = parent->hmp;
2252         hammer2_chain_t *chain;
2253         int error;
2254
2255         /*
2256          * Allocate a chain structure representing the existing media
2257          * entry.  Resulting chain has one ref and is not locked.
2258          */
2259         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
2260                 chain = hammer2_chain_alloc(hmp, NULL, bref);
2261         else
2262                 chain = hammer2_chain_alloc(hmp, parent->pmp, bref);
2263         /* ref'd chain returned */
2264
2265         /*
2266          * Flag that the chain is in the parent's blockmap so delete/flush
2267          * knows what to do with it.
2268          */
2269         atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
2270
2271         /*
2272          * chain must be locked to avoid unexpected ripouts
2273          */
2274         hammer2_chain_lock(chain, how);
2275
2276         /*
2277          * Link the chain into its parent.  A spinlock is required to safely
2278          * access the RBTREE, and it is possible to collide with another
2279          * hammer2_chain_get() operation because the caller might only hold
2280          * a shared lock on the parent.
2281          *
2282          * NOTE: Get races can occur quite often when we distribute
2283          *       asynchronous read-aheads across multiple threads.
2284          */
2285         KKASSERT(parent->refs > 0);
2286         error = hammer2_chain_insert(parent, chain,
2287                                      HAMMER2_CHAIN_INSERT_SPIN |
2288                                      HAMMER2_CHAIN_INSERT_RACE,
2289                                      generation);
2290         if (error) {
2291                 KKASSERT((chain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
2292                 /*kprintf("chain %p get race\n", chain);*/
2293                 hammer2_chain_unlock(chain);
2294                 hammer2_chain_drop(chain);
2295                 chain = NULL;
2296         } else {
2297                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
2298         }
2299
2300         /*
2301          * Return our new chain referenced but not locked, or NULL if
2302          * a race occurred.
2303          */
2304         return (chain);
2305 }
2306
2307 /*
2308  * Lookup initialization/completion API
2309  */
2310 hammer2_chain_t *
2311 hammer2_chain_lookup_init(hammer2_chain_t *parent, int flags)
2312 {
2313         hammer2_chain_ref(parent);
2314         if (flags & HAMMER2_LOOKUP_SHARED) {
2315                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS |
2316                                            HAMMER2_RESOLVE_SHARED);
2317         } else {
2318                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2319         }
2320         return (parent);
2321 }
2322
2323 void
2324 hammer2_chain_lookup_done(hammer2_chain_t *parent)
2325 {
2326         if (parent) {
2327                 hammer2_chain_unlock(parent);
2328                 hammer2_chain_drop(parent);
2329         }
2330 }
2331
2332 /*
2333  * Take the locked chain and return a locked parent.  The chain remains
2334  * locked on return, but may have to be temporarily unlocked to acquire
2335  * the parent.  Because of this, (chain) must be stable and cannot be
2336  * deleted while it was temporarily unlocked (typically means that (chain)
2337  * is an inode).
2338  *
2339  * Pass HAMMER2_RESOLVE_* flags in flags.
2340  *
2341  * This will work even if the chain is errored, and the caller can check
2342  * parent->error on return if desired since the parent will be locked.
2343  *
2344  * This function handles the lock order reversal.
2345  */
2346 hammer2_chain_t *
2347 hammer2_chain_getparent(hammer2_chain_t *chain, int flags)
2348 {
2349         hammer2_chain_t *parent;
2350
2351         /*
2352          * Be careful of order, chain must be unlocked before parent
2353          * is locked below to avoid a deadlock.  Try it trivially first.
2354          */
2355         parent = chain->parent;
2356         if (parent == NULL)
2357                 panic("hammer2_chain_getparent: no parent");
2358         hammer2_chain_ref(parent);
2359         if (hammer2_chain_lock(parent, flags|HAMMER2_RESOLVE_NONBLOCK) == 0)
2360                 return parent;
2361
2362         for (;;) {
2363                 hammer2_chain_unlock(chain);
2364                 hammer2_chain_lock(parent, flags);
2365                 hammer2_chain_lock(chain, flags);
2366
2367                 /*
2368                  * Parent relinking races are quite common.  We have to get
2369                  * it right or we will blow up the block table.
2370                  */
2371                 if (chain->parent == parent)
2372                         break;
2373                 hammer2_chain_unlock(parent);
2374                 hammer2_chain_drop(parent);
2375                 cpu_ccfence();
2376                 parent = chain->parent;
2377                 if (parent == NULL)
2378                         panic("hammer2_chain_getparent: no parent");
2379                 hammer2_chain_ref(parent);
2380         }
2381         return parent;
2382 }
2383
2384 /*
2385  * Take the locked chain and return a locked parent.  The chain is unlocked
2386  * and dropped.  *chainp is set to the returned parent as a convenience.
2387  * Pass HAMMER2_RESOLVE_* flags in flags.
2388  *
2389  * This will work even if the chain is errored, and the caller can check
2390  * parent->error on return if desired since the parent will be locked.
2391  *
2392  * The chain does NOT need to be stable.  We use a tracking structure
2393  * to track the expected parent if the chain is deleted out from under us.
2394  *
2395  * This function handles the lock order reversal.
2396  */
2397 hammer2_chain_t *
2398 hammer2_chain_repparent(hammer2_chain_t **chainp, int flags)
2399 {
2400         hammer2_chain_t *chain;
2401         hammer2_chain_t *parent;
2402         struct hammer2_reptrack reptrack;
2403         struct hammer2_reptrack **repp;
2404
2405         /*
2406          * Be careful of order, chain must be unlocked before parent
2407          * is locked below to avoid a deadlock.  Try it trivially first.
2408          */
2409         chain = *chainp;
2410         parent = chain->parent;
2411         if (parent == NULL) {
2412                 hammer2_spin_unex(&chain->core.spin);
2413                 panic("hammer2_chain_repparent: no parent");
2414         }
2415         hammer2_chain_ref(parent);
2416         if (hammer2_chain_lock(parent, flags|HAMMER2_RESOLVE_NONBLOCK) == 0) {
2417                 hammer2_chain_unlock(chain);
2418                 hammer2_chain_drop(chain);
2419                 *chainp = parent;
2420
2421                 return parent;
2422         }
2423
2424         /*
2425          * Ok, now it gets a bit nasty.  There are multiple situations where
2426          * the parent might be in the middle of a deletion, or where the child
2427          * (chain) might be deleted the instant we let go of its lock.
2428          * We can potentially end up in a no-win situation!
2429          *
2430          * In particular, the indirect_maintenance() case can cause these
2431          * situations.
2432          *
2433          * To deal with this we install a reptrack structure in the parent
2434          * This reptrack structure 'owns' the parent ref and will automatically
2435          * migrate to the parent's parent if the parent is deleted permanently.
2436          */
2437         hammer2_spin_init(&reptrack.spin, "h2reptrk");
2438         reptrack.chain = parent;
2439         hammer2_chain_ref(parent);              /* for the reptrack */
2440
2441         hammer2_spin_ex(&parent->core.spin);
2442         reptrack.next = parent->core.reptrack;
2443         parent->core.reptrack = &reptrack;
2444         hammer2_spin_unex(&parent->core.spin);
2445
2446         hammer2_chain_unlock(chain);
2447         hammer2_chain_drop(chain);
2448         chain = NULL;   /* gone */
2449
2450         /*
2451          * At the top of this loop, chain is gone and parent is refd both
2452          * by us explicitly AND via our reptrack.  We are attempting to
2453          * lock parent.
2454          */
2455         for (;;) {
2456                 hammer2_chain_lock(parent, flags);
2457
2458                 if (reptrack.chain == parent)
2459                         break;
2460                 hammer2_chain_unlock(parent);
2461                 hammer2_chain_drop(parent);
2462
2463                 kprintf("hammer2: debug REPTRACK %p->%p\n",
2464                         parent, reptrack.chain);
2465                 hammer2_spin_ex(&reptrack.spin);
2466                 parent = reptrack.chain;
2467                 hammer2_chain_ref(parent);
2468                 hammer2_spin_unex(&reptrack.spin);
2469         }
2470
2471         /*
2472          * Once parent is locked and matches our reptrack, our reptrack
2473          * will be stable and we have our parent.  We can unlink our
2474          * reptrack.
2475          *
2476          * WARNING!  Remember that the chain lock might be shared.  Chains
2477          *           locked shared have stable parent linkages.
2478          */
2479         hammer2_spin_ex(&parent->core.spin);
2480         repp = &parent->core.reptrack;
2481         while (*repp != &reptrack)
2482                 repp = &(*repp)->next;
2483         *repp = reptrack.next;
2484         hammer2_spin_unex(&parent->core.spin);
2485
2486         hammer2_chain_drop(parent);     /* reptrack ref */
2487         *chainp = parent;               /* return parent lock+ref */
2488
2489         return parent;
2490 }
2491
2492 /*
2493  * Dispose of any linked reptrack structures in (chain) by shifting them to
2494  * (parent).  Both (chain) and (parent) must be exclusively locked.
2495  *
2496  * This is interlocked against any children of (chain) on the other side.
2497  * No children so remain as-of when this is called so we can test
2498  * core.reptrack without holding the spin-lock.
2499  *
2500  * Used whenever the caller intends to permanently delete chains related
2501  * to topological recursions (BREF_TYPE_INDIRECT, BREF_TYPE_FREEMAP_NODE),
2502  * where the chains underneath the node being deleted are given a new parent
2503  * above the node being deleted.
2504  */
2505 static
2506 void
2507 hammer2_chain_repchange(hammer2_chain_t *parent, hammer2_chain_t *chain)
2508 {
2509         struct hammer2_reptrack *reptrack;
2510
2511         KKASSERT(chain->core.live_count == 0 && RB_EMPTY(&chain->core.rbtree));
2512         while (chain->core.reptrack) {
2513                 hammer2_spin_ex(&parent->core.spin);
2514                 hammer2_spin_ex(&chain->core.spin);
2515                 reptrack = chain->core.reptrack;
2516                 if (reptrack == NULL) {
2517                         hammer2_spin_unex(&chain->core.spin);
2518                         hammer2_spin_unex(&parent->core.spin);
2519                         break;
2520                 }
2521                 hammer2_spin_ex(&reptrack->spin);
2522                 chain->core.reptrack = reptrack->next;
2523                 reptrack->chain = parent;
2524                 reptrack->next = parent->core.reptrack;
2525                 parent->core.reptrack = reptrack;
2526                 hammer2_chain_ref(parent);              /* reptrack */
2527
2528                 hammer2_spin_unex(&chain->core.spin);
2529                 hammer2_spin_unex(&parent->core.spin);
2530                 kprintf("hammer2: debug repchange %p %p->%p\n",
2531                         reptrack, chain, parent);
2532                 hammer2_chain_drop(chain);              /* reptrack */
2533         }
2534 }
2535
2536 /*
2537  * Locate the first chain whos key range overlaps (key_beg, key_end) inclusive.
2538  * (*parentp) typically points to an inode but can also point to a related
2539  * indirect block and this function will recurse upwards and find the inode
2540  * or the nearest undeleted indirect block covering the key range.
2541  *
2542  * This function unconditionally sets *errorp, replacing any previous value.
2543  *
2544  * (*parentp) must be exclusive or shared locked (depending on flags) and
2545  * referenced and can be an inode or an existing indirect block within the
2546  * inode.
2547  *
2548  * If (*parent) is errored out, this function will not attempt to recurse
2549  * the radix tree and will return NULL along with an appropriate *errorp.
2550  * If NULL is returned and *errorp is 0, the requested lookup could not be
2551  * located.
2552  *
2553  * On return (*parentp) will be modified to point at the deepest parent chain
2554  * element encountered during the search, as a helper for an insertion or
2555  * deletion.
2556  *
2557  * The new (*parentp) will be locked shared or exclusive (depending on flags),
2558  * and referenced, and the old will be unlocked and dereferenced (no change
2559  * if they are both the same).  This is particularly important if the caller
2560  * wishes to insert a new chain, (*parentp) will be set properly even if NULL
2561  * is returned, as long as no error occurred.
2562  *
2563  * The matching chain will be returned locked according to flags.
2564  *
2565  * --
2566  *
2567  * NULL is returned if no match was found, but (*parentp) will still
2568  * potentially be adjusted.
2569  *
2570  * On return (*key_nextp) will point to an iterative value for key_beg.
2571  * (If NULL is returned (*key_nextp) is set to (key_end + 1)).
2572  *
2573  * This function will also recurse up the chain if the key is not within the
2574  * current parent's range.  (*parentp) can never be set to NULL.  An iteration
2575  * can simply allow (*parentp) to float inside the loop.
2576  *
2577  * NOTE!  chain->data is not always resolved.  By default it will not be
2578  *        resolved for BREF_TYPE_DATA, FREEMAP_NODE, or FREEMAP_LEAF.  Use
2579  *        HAMMER2_LOOKUP_ALWAYS to force resolution (but be careful w/
2580  *        BREF_TYPE_DATA as the device buffer can alias the logical file
2581  *        buffer).
2582  */
2583
2584 hammer2_chain_t *
2585 hammer2_chain_lookup(hammer2_chain_t **parentp, hammer2_key_t *key_nextp,
2586                      hammer2_key_t key_beg, hammer2_key_t key_end,
2587                      int *errorp, int flags)
2588 {
2589         hammer2_dev_t *hmp;
2590         hammer2_chain_t *parent;
2591         hammer2_chain_t *chain;
2592         hammer2_blockref_t *base;
2593         hammer2_blockref_t *bref;
2594         hammer2_blockref_t bcopy;
2595         hammer2_key_t scan_beg;
2596         hammer2_key_t scan_end;
2597         int count = 0;
2598         int how_always = HAMMER2_RESOLVE_ALWAYS;
2599         int how_maybe = HAMMER2_RESOLVE_MAYBE;
2600         int how;
2601         int generation;
2602         int maxloops = 300000;
2603         volatile hammer2_mtx_t save_mtx;
2604
2605         if (flags & HAMMER2_LOOKUP_ALWAYS) {
2606                 how_maybe = how_always;
2607                 how = HAMMER2_RESOLVE_ALWAYS;
2608         } else if (flags & HAMMER2_LOOKUP_NODATA) {
2609                 how = HAMMER2_RESOLVE_NEVER;
2610         } else {
2611                 how = HAMMER2_RESOLVE_MAYBE;
2612         }
2613         if (flags & HAMMER2_LOOKUP_SHARED) {
2614                 how_maybe |= HAMMER2_RESOLVE_SHARED;
2615                 how_always |= HAMMER2_RESOLVE_SHARED;
2616                 how |= HAMMER2_RESOLVE_SHARED;
2617         }
2618
2619         /*
2620          * Recurse (*parentp) upward if necessary until the parent completely
2621          * encloses the key range or we hit the inode.
2622          *
2623          * Handle races against the flusher deleting indirect nodes on its
2624          * way back up by continuing to recurse upward past the deletion.
2625          */
2626         parent = *parentp;
2627         hmp = parent->hmp;
2628         *errorp = 0;
2629
2630         while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
2631                parent->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2632                 scan_beg = parent->bref.key;
2633                 scan_end = scan_beg +
2634                            ((hammer2_key_t)1 << parent->bref.keybits) - 1;
2635                 if ((parent->flags & HAMMER2_CHAIN_DELETED) == 0) {
2636                         if (key_beg >= scan_beg && key_end <= scan_end)
2637                                 break;
2638                 }
2639                 parent = hammer2_chain_repparent(parentp, how_maybe);
2640         }
2641 again:
2642         if (--maxloops == 0)
2643                 panic("hammer2_chain_lookup: maxloops");
2644         /*
2645          * Locate the blockref array.  Currently we do a fully associative
2646          * search through the array.
2647          */
2648         switch(parent->bref.type) {
2649         case HAMMER2_BREF_TYPE_INODE:
2650                 /*
2651                  * Special shortcut for embedded data returns the inode
2652                  * itself.  Callers must detect this condition and access
2653                  * the embedded data (the strategy code does this for us).
2654                  *
2655                  * This is only applicable to regular files and softlinks.
2656                  *
2657                  * We need a second lock on parent.  Since we already have
2658                  * a lock we must pass LOCKAGAIN to prevent unexpected
2659                  * blocking (we don't want to block on a second shared
2660                  * ref if an exclusive lock is pending)
2661                  */
2662                 if (parent->data->ipdata.meta.op_flags &
2663                     HAMMER2_OPFLAG_DIRECTDATA) {
2664                         if (flags & HAMMER2_LOOKUP_NODIRECT) {
2665                                 chain = NULL;
2666                                 *key_nextp = key_end + 1;
2667                                 goto done;
2668                         }
2669                         hammer2_chain_ref(parent);
2670                         hammer2_chain_lock(parent, how_always |
2671                                                    HAMMER2_RESOLVE_LOCKAGAIN);
2672                         *key_nextp = key_end + 1;
2673                         return (parent);
2674                 }
2675                 base = &parent->data->ipdata.u.blockset.blockref[0];
2676                 count = HAMMER2_SET_COUNT;
2677                 break;
2678         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2679         case HAMMER2_BREF_TYPE_INDIRECT:
2680                 /*
2681                  * Handle MATCHIND on the parent
2682                  */
2683                 if (flags & HAMMER2_LOOKUP_MATCHIND) {
2684                         scan_beg = parent->bref.key;
2685                         scan_end = scan_beg +
2686                                ((hammer2_key_t)1 << parent->bref.keybits) - 1;
2687                         if (key_beg == scan_beg && key_end == scan_end) {
2688                                 chain = parent;
2689                                 hammer2_chain_ref(chain);
2690                                 hammer2_chain_lock(chain, how_maybe);
2691                                 *key_nextp = scan_end + 1;
2692                                 goto done;
2693                         }
2694                 }
2695
2696                 /*
2697                  * Optimize indirect blocks in the INITIAL state to avoid
2698                  * I/O.
2699                  */
2700                 if (parent->flags & HAMMER2_CHAIN_INITIAL) {
2701                         base = NULL;
2702                 } else {
2703                         if (parent->data == NULL) {
2704                                 kprintf("parent->data is NULL %p\n", parent);
2705                                 while (1)
2706                                         tsleep(parent, 0, "xxx", 0);
2707                         }
2708                         base = &parent->data->npdata[0];
2709                 }
2710                 count = parent->bytes / sizeof(hammer2_blockref_t);
2711                 break;
2712         case HAMMER2_BREF_TYPE_VOLUME:
2713                 base = &parent->data->voldata.sroot_blockset.blockref[0];
2714                 count = HAMMER2_SET_COUNT;
2715                 break;
2716         case HAMMER2_BREF_TYPE_FREEMAP:
2717                 base = &parent->data->blkset.blockref[0];
2718                 count = HAMMER2_SET_COUNT;
2719                 break;
2720         default:
2721                 kprintf("hammer2_chain_lookup: unrecognized "
2722                         "blockref(B) type: %d",
2723                         parent->bref.type);
2724                 while (1)
2725                         tsleep(&base, 0, "dead", 0);
2726                 panic("hammer2_chain_lookup: unrecognized "
2727                       "blockref(B) type: %d",
2728                       parent->bref.type);
2729                 base = NULL;    /* safety */
2730                 count = 0;      /* safety */
2731         }
2732
2733         /*
2734          * No lookup is possible if the parent is errored.  We delayed
2735          * this check as long as we could to ensure that the parent backup,
2736          * embedded data, and MATCHIND code could still execute.
2737          */
2738         if (parent->error) {
2739                 *errorp = parent->error;
2740                 return NULL;
2741         }
2742
2743         /*
2744          * Merged scan to find next candidate.
2745          *
2746          * hammer2_base_*() functions require the parent->core.live_* fields
2747          * to be synchronized.
2748          *
2749          * We need to hold the spinlock to access the block array and RB tree
2750          * and to interlock chain creation.
2751          */
2752         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
2753                 hammer2_chain_countbrefs(parent, base, count);
2754
2755         /*
2756          * Combined search
2757          */
2758         hammer2_spin_ex(&parent->core.spin);
2759         chain = hammer2_combined_find(parent, base, count,
2760                                       key_nextp,
2761                                       key_beg, key_end,
2762                                       &bref);
2763         generation = parent->core.generation;
2764
2765         /*
2766          * Exhausted parent chain, iterate.
2767          */
2768         if (bref == NULL) {
2769                 KKASSERT(chain == NULL);
2770                 hammer2_spin_unex(&parent->core.spin);
2771                 if (key_beg == key_end) /* short cut single-key case */
2772                         return (NULL);
2773
2774                 /*
2775                  * Stop if we reached the end of the iteration.
2776                  */
2777                 if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT &&
2778                     parent->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2779                         return (NULL);
2780                 }
2781
2782                 /*
2783                  * Calculate next key, stop if we reached the end of the
2784                  * iteration, otherwise go up one level and loop.
2785                  */
2786                 key_beg = parent->bref.key +
2787                           ((hammer2_key_t)1 << parent->bref.keybits);
2788                 if (key_beg == 0 || key_beg > key_end)
2789                         return (NULL);
2790                 parent = hammer2_chain_repparent(parentp, how_maybe);
2791                 goto again;
2792         }
2793
2794         /*
2795          * Selected from blockref or in-memory chain.
2796          */
2797         bcopy = *bref;
2798         if (chain == NULL) {
2799                 hammer2_spin_unex(&parent->core.spin);
2800                 if (bcopy.type == HAMMER2_BREF_TYPE_INDIRECT ||
2801                     bcopy.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2802                         chain = hammer2_chain_get(parent, generation,
2803                                                   &bcopy, how_maybe);
2804                 } else {
2805                         chain = hammer2_chain_get(parent, generation,
2806                                                   &bcopy, how);
2807                 }
2808                 if (chain == NULL)
2809                         goto again;
2810         } else {
2811                 hammer2_chain_ref(chain);
2812                 hammer2_spin_unex(&parent->core.spin);
2813
2814                 /*
2815                  * chain is referenced but not locked.  We must lock the
2816                  * chain to obtain definitive state.
2817                  */
2818                 if (bcopy.type == HAMMER2_BREF_TYPE_INDIRECT ||
2819                     bcopy.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2820                         hammer2_chain_lock(chain, how_maybe);
2821                 } else {
2822                         hammer2_chain_lock(chain, how);
2823                 }
2824                 KKASSERT(chain->parent == parent);
2825         }
2826         if (bcmp(&bcopy, &chain->bref, sizeof(bcopy)) ||
2827             chain->parent != parent) {
2828                 hammer2_chain_unlock(chain);
2829                 hammer2_chain_drop(chain);
2830                 chain = NULL;   /* SAFETY */
2831                 goto again;
2832         }
2833
2834
2835         /*
2836          * Skip deleted chains (XXX cache 'i' end-of-block-array? XXX)
2837          *
2838          * NOTE: Chain's key range is not relevant as there might be
2839          *       one-offs within the range that are not deleted.
2840          *
2841          * NOTE: Lookups can race delete-duplicate because
2842          *       delete-duplicate does not lock the parent's core
2843          *       (they just use the spinlock on the core).
2844          */
2845         if (chain->flags & HAMMER2_CHAIN_DELETED) {
2846                 kprintf("skip deleted chain %016jx.%02x key=%016jx\n",
2847                         chain->bref.data_off, chain->bref.type,
2848                         chain->bref.key);
2849                 hammer2_chain_unlock(chain);
2850                 hammer2_chain_drop(chain);
2851                 chain = NULL;   /* SAFETY */
2852                 key_beg = *key_nextp;
2853                 if (key_beg == 0 || key_beg > key_end)
2854                         return(NULL);
2855                 goto again;
2856         }
2857
2858         /*
2859          * If the chain element is an indirect block it becomes the new
2860          * parent and we loop on it.  We must maintain our top-down locks
2861          * to prevent the flusher from interfering (i.e. doing a
2862          * delete-duplicate and leaving us recursing down a deleted chain).
2863          *
2864          * The parent always has to be locked with at least RESOLVE_MAYBE
2865          * so we can access its data.  It might need a fixup if the caller
2866          * passed incompatible flags.  Be careful not to cause a deadlock
2867          * as a data-load requires an exclusive lock.
2868          *
2869          * If HAMMER2_LOOKUP_MATCHIND is set and the indirect block's key
2870          * range is within the requested key range we return the indirect
2871          * block and do NOT loop.  This is usually only used to acquire
2872          * freemap nodes.
2873          */
2874         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
2875             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2876                 save_mtx = parent->lock;
2877                 hammer2_chain_unlock(parent);
2878                 hammer2_chain_drop(parent);
2879                 *parentp = parent = chain;
2880                 chain = NULL;   /* SAFETY */
2881                 goto again;
2882         }
2883 done:
2884         /*
2885          * All done, return the locked chain.
2886          *
2887          * If the caller does not want a locked chain, replace the lock with
2888          * a ref.  Perhaps this can eventually be optimized to not obtain the
2889          * lock in the first place for situations where the data does not
2890          * need to be resolved.
2891          *
2892          * NOTE! A chain->error must be tested by the caller upon return.
2893          *       *errorp is only set based on issues which occur while
2894          *       trying to reach the chain.
2895          */
2896         return (chain);
2897 }
2898
2899 /*
2900  * After having issued a lookup we can iterate all matching keys.
2901  *
2902  * If chain is non-NULL we continue the iteration from just after it's index.
2903  *
2904  * If chain is NULL we assume the parent was exhausted and continue the
2905  * iteration at the next parent.
2906  *
2907  * If a fatal error occurs (typically an I/O error), a dummy chain is
2908  * returned with chain->error and error-identifying information set.  This
2909  * chain will assert if you try to do anything fancy with it.
2910  *
2911  * XXX Depending on where the error occurs we should allow continued iteration.
2912  *
2913  * parent must be locked on entry and remains locked throughout.  chain's
2914  * lock status must match flags.  Chain is always at least referenced.
2915  *
2916  * WARNING!  The MATCHIND flag does not apply to this function.
2917  */
2918 hammer2_chain_t *
2919 hammer2_chain_next(hammer2_chain_t **parentp, hammer2_chain_t *chain,
2920                    hammer2_key_t *key_nextp,
2921                    hammer2_key_t key_beg, hammer2_key_t key_end,
2922                    int *errorp, int flags)
2923 {
2924         hammer2_chain_t *parent;
2925         int how_maybe;
2926
2927         /*
2928          * Calculate locking flags for upward recursion.
2929          */
2930         how_maybe = HAMMER2_RESOLVE_MAYBE;
2931         if (flags & HAMMER2_LOOKUP_SHARED)
2932                 how_maybe |= HAMMER2_RESOLVE_SHARED;
2933
2934         parent = *parentp;
2935         *errorp = 0;
2936
2937         /*
2938          * Calculate the next index and recalculate the parent if necessary.
2939          */
2940         if (chain) {
2941                 key_beg = chain->bref.key +
2942                           ((hammer2_key_t)1 << chain->bref.keybits);
2943                 hammer2_chain_unlock(chain);
2944                 hammer2_chain_drop(chain);
2945
2946                 /*
2947                  * chain invalid past this point, but we can still do a
2948                  * pointer comparison w/parent.
2949                  *
2950                  * Any scan where the lookup returned degenerate data embedded
2951                  * in the inode has an invalid index and must terminate.
2952                  */
2953                 if (chain == parent)
2954                         return(NULL);
2955                 if (key_beg == 0 || key_beg > key_end)
2956                         return(NULL);
2957                 chain = NULL;
2958         } else if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT &&
2959                    parent->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE) {
2960                 /*
2961                  * We reached the end of the iteration.
2962                  */
2963                 return (NULL);
2964         } else {
2965                 /*
2966                  * Continue iteration with next parent unless the current
2967                  * parent covers the range.
2968                  *
2969                  * (This also handles the case of a deleted, empty indirect
2970                  * node).
2971                  */
2972                 key_beg = parent->bref.key +
2973                           ((hammer2_key_t)1 << parent->bref.keybits);
2974                 if (key_beg == 0 || key_beg > key_end)
2975                         return (NULL);
2976                 parent = hammer2_chain_repparent(parentp, how_maybe);
2977         }
2978
2979         /*
2980          * And execute
2981          */
2982         return (hammer2_chain_lookup(parentp, key_nextp,
2983                                      key_beg, key_end,
2984                                      errorp, flags));
2985 }
2986
2987 /*
2988  * Caller wishes to iterate chains under parent, loading new chains into
2989  * chainp.  Caller must initialize *chainp to NULL and *firstp to 1, and
2990  * then call hammer2_chain_scan() repeatedly until a non-zero return.
2991  * During the scan, *firstp will be set to 0 and (*chainp) will be replaced
2992  * with the returned chain for the scan.  The returned *chainp will be
2993  * locked and referenced.  Any prior contents will be unlocked and dropped.
2994  *
2995  * Caller should check the return value.  A normal scan EOF will return
2996  * exactly HAMMER2_ERROR_EOF.  Any other non-zero value indicates an
2997  * error trying to access parent data.  Any error in the returned chain
2998  * must be tested separately by the caller.
2999  *
3000  * (*chainp) is dropped on each scan, but will only be set if the returned
3001  * element itself can recurse.  Leaf elements are NOT resolved, loaded, or
3002  * returned via *chainp.  The caller will get their bref only.
3003  *
3004  * The raw scan function is similar to lookup/next but does not seek to a key.
3005  * Blockrefs are iterated via first_bref = (parent, NULL) and
3006  * next_chain = (parent, bref).
3007  *
3008  * The passed-in parent must be locked and its data resolved.  The function
3009  * nominally returns a locked and referenced *chainp != NULL for chains
3010  * the caller might need to recurse on (and will dipose of any *chainp passed
3011  * in).  The caller must check the chain->bref.type either way.
3012  */
3013 int
3014 hammer2_chain_scan(hammer2_chain_t *parent, hammer2_chain_t **chainp,
3015                    hammer2_blockref_t *bref, int *firstp,
3016                    int flags)
3017 {
3018         hammer2_dev_t *hmp;
3019         hammer2_blockref_t *base;
3020         hammer2_blockref_t *bref_ptr;
3021         hammer2_key_t key;
3022         hammer2_key_t next_key;
3023         hammer2_chain_t *chain = NULL;
3024         int count = 0;
3025         int how_always = HAMMER2_RESOLVE_ALWAYS;
3026         int how_maybe = HAMMER2_RESOLVE_MAYBE;
3027         int how;
3028         int generation;
3029         int maxloops = 300000;
3030         int error;
3031
3032         hmp = parent->hmp;
3033         error = 0;
3034
3035         /*
3036          * Scan flags borrowed from lookup.
3037          */
3038         if (flags & HAMMER2_LOOKUP_ALWAYS) {
3039                 how_maybe = how_always;
3040                 how = HAMMER2_RESOLVE_ALWAYS;
3041         } else if (flags & HAMMER2_LOOKUP_NODATA) {
3042                 how = HAMMER2_RESOLVE_NEVER;
3043         } else {
3044                 how = HAMMER2_RESOLVE_MAYBE;
3045         }
3046         if (flags & HAMMER2_LOOKUP_SHARED) {
3047                 how_maybe |= HAMMER2_RESOLVE_SHARED;
3048                 how_always |= HAMMER2_RESOLVE_SHARED;
3049                 how |= HAMMER2_RESOLVE_SHARED;
3050         }
3051
3052         /*
3053          * Calculate key to locate first/next element, unlocking the previous
3054          * element as we go.  Be careful, the key calculation can overflow.
3055          *
3056          * (also reset bref to NULL)
3057          */
3058         if (*firstp) {
3059                 key = 0;
3060                 *firstp = 0;
3061         } else {
3062                 key = bref->key + ((hammer2_key_t)1 << bref->keybits);
3063                 if ((chain = *chainp) != NULL) {
3064                         *chainp = NULL;
3065                         hammer2_chain_unlock(chain);
3066                         hammer2_chain_drop(chain);
3067                         chain = NULL;
3068                 }
3069                 if (key == 0) {
3070                         error |= HAMMER2_ERROR_EOF;
3071                         goto done;
3072                 }
3073         }
3074
3075 again:
3076         if (parent->error) {
3077                 error = parent->error;
3078                 goto done;
3079         }
3080         if (--maxloops == 0)
3081                 panic("hammer2_chain_scan: maxloops");
3082
3083         /*
3084          * Locate the blockref array.  Currently we do a fully associative
3085          * search through the array.
3086          */
3087         switch(parent->bref.type) {
3088         case HAMMER2_BREF_TYPE_INODE:
3089                 /*
3090                  * An inode with embedded data has no sub-chains.
3091                  *
3092                  * WARNING! Bulk scan code may pass a static chain marked
3093                  *          as BREF_TYPE_INODE with a copy of the volume
3094                  *          root blockset to snapshot the volume.
3095                  */
3096                 if (parent->data->ipdata.meta.op_flags &
3097                     HAMMER2_OPFLAG_DIRECTDATA) {
3098                         error |= HAMMER2_ERROR_EOF;
3099                         goto done;
3100                 }
3101                 base = &parent->data->ipdata.u.blockset.blockref[0];
3102                 count = HAMMER2_SET_COUNT;
3103                 break;
3104         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3105         case HAMMER2_BREF_TYPE_INDIRECT:
3106                 /*
3107                  * Optimize indirect blocks in the INITIAL state to avoid
3108                  * I/O.
3109                  */
3110                 if (parent->flags & HAMMER2_CHAIN_INITIAL) {
3111                         base = NULL;
3112                 } else {
3113                         if (parent->data == NULL)
3114                                 panic("parent->data is NULL");
3115                         base = &parent->data->npdata[0];
3116                 }
3117                 count = parent->bytes / sizeof(hammer2_blockref_t);
3118                 break;
3119         case HAMMER2_BREF_TYPE_VOLUME:
3120                 base = &parent->data->voldata.sroot_blockset.blockref[0];
3121                 count = HAMMER2_SET_COUNT;
3122                 break;
3123         case HAMMER2_BREF_TYPE_FREEMAP:
3124                 base = &parent->data->blkset.blockref[0];
3125                 count = HAMMER2_SET_COUNT;
3126                 break;
3127         default:
3128                 panic("hammer2_chain_scan: unrecognized blockref type: %d",
3129                       parent->bref.type);
3130                 base = NULL;    /* safety */
3131                 count = 0;      /* safety */
3132         }
3133
3134         /*
3135          * Merged scan to find next candidate.
3136          *
3137          * hammer2_base_*() functions require the parent->core.live_* fields
3138          * to be synchronized.
3139          *
3140          * We need to hold the spinlock to access the block array and RB tree
3141          * and to interlock chain creation.
3142          */
3143         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
3144                 hammer2_chain_countbrefs(parent, base, count);
3145
3146         next_key = 0;
3147         bref_ptr = NULL;
3148         hammer2_spin_ex(&parent->core.spin);
3149         chain = hammer2_combined_find(parent, base, count,
3150                                       &next_key,
3151                                       key, HAMMER2_KEY_MAX,
3152                                       &bref_ptr);
3153         generation = parent->core.generation;
3154
3155         /*
3156          * Exhausted parent chain, we're done.
3157          */
3158         if (bref_ptr == NULL) {
3159                 hammer2_spin_unex(&parent->core.spin);
3160                 KKASSERT(chain == NULL);
3161                 error |= HAMMER2_ERROR_EOF;
3162                 goto done;
3163         }
3164
3165         /*
3166          * Copy into the supplied stack-based blockref.
3167          */
3168         *bref = *bref_ptr;
3169
3170         /*
3171          * Selected from blockref or in-memory chain.
3172          */
3173         if (chain == NULL) {
3174                 switch(bref->type) {
3175                 case HAMMER2_BREF_TYPE_INODE:
3176                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3177                 case HAMMER2_BREF_TYPE_INDIRECT:
3178                 case HAMMER2_BREF_TYPE_VOLUME:
3179                 case HAMMER2_BREF_TYPE_FREEMAP:
3180                         /*
3181                          * Recursion, always get the chain
3182                          */
3183                         hammer2_spin_unex(&parent->core.spin);
3184                         chain = hammer2_chain_get(parent, generation,
3185                                                   bref, how);
3186                         if (chain == NULL)
3187                                 goto again;
3188                         break;
3189                 default:
3190                         /*
3191                          * No recursion, do not waste time instantiating
3192                          * a chain, just iterate using the bref.
3193                          */
3194                         hammer2_spin_unex(&parent->core.spin);
3195                         break;
3196                 }
3197         } else {
3198                 /*
3199                  * Recursion or not we need the chain in order to supply
3200                  * the bref.
3201                  */
3202                 hammer2_chain_ref(chain);
3203                 hammer2_spin_unex(&parent->core.spin);
3204                 hammer2_chain_lock(chain, how);
3205         }
3206         if (chain &&
3207             (bcmp(bref, &chain->bref, sizeof(*bref)) ||
3208              chain->parent != parent)) {
3209                 hammer2_chain_unlock(chain);
3210                 hammer2_chain_drop(chain);
3211                 chain = NULL;
3212                 goto again;
3213         }
3214
3215         /*
3216          * Skip deleted chains (XXX cache 'i' end-of-block-array? XXX)
3217          *
3218          * NOTE: chain's key range is not relevant as there might be
3219          *       one-offs within the range that are not deleted.
3220          *
3221          * NOTE: XXX this could create problems with scans used in
3222          *       situations other than mount-time recovery.
3223          *
3224          * NOTE: Lookups can race delete-duplicate because
3225          *       delete-duplicate does not lock the parent's core
3226          *       (they just use the spinlock on the core).
3227          */
3228         if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
3229                 hammer2_chain_unlock(chain);
3230                 hammer2_chain_drop(chain);
3231                 chain = NULL;
3232
3233                 key = next_key;
3234                 if (key == 0) {
3235                         error |= HAMMER2_ERROR_EOF;
3236                         goto done;
3237                 }
3238                 goto again;
3239         }
3240
3241 done:
3242         /*
3243          * All done, return the bref or NULL, supply chain if necessary.
3244          */
3245         if (chain)
3246                 *chainp = chain;
3247         return (error);
3248 }
3249
3250 /*
3251  * Create and return a new hammer2 system memory structure of the specified
3252  * key, type and size and insert it under (*parentp).  This is a full
3253  * insertion, based on the supplied key/keybits, and may involve creating
3254  * indirect blocks and moving other chains around via delete/duplicate.
3255  *
3256  * This call can be made with parent == NULL as long as a non -1 methods
3257  * is supplied.  hmp must also be supplied in this situation (otherwise
3258  * hmp is extracted from the supplied parent).  The chain will be detached
3259  * from the topology.  A later call with both parent and chain can be made
3260  * to attach it.
3261  *
3262  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (*parentp) TO THE INSERTION
3263  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
3264  * FULL.  This typically means that the caller is creating the chain after
3265  * doing a hammer2_chain_lookup().
3266  *
3267  * (*parentp) must be exclusive locked and may be replaced on return
3268  * depending on how much work the function had to do.
3269  *
3270  * (*parentp) must not be errored or this function will assert.
3271  *
3272  * (*chainp) usually starts out NULL and returns the newly created chain,
3273  * but if the caller desires the caller may allocate a disconnected chain
3274  * and pass it in instead.
3275  *
3276  * This function should NOT be used to insert INDIRECT blocks.  It is
3277  * typically used to create/insert inodes and data blocks.
3278  *
3279  * Caller must pass-in an exclusively locked parent the new chain is to
3280  * be inserted under, and optionally pass-in a disconnected, exclusively
3281  * locked chain to insert (else we create a new chain).  The function will
3282  * adjust (*parentp) as necessary, create or connect the chain, and
3283  * return an exclusively locked chain in *chainp.
3284  *
3285  * When creating a PFSROOT inode under the super-root, pmp is typically NULL
3286  * and will be reassigned.
3287  *
3288  * NOTE: returns HAMMER_ERROR_* flags
3289  */
3290 int
3291 hammer2_chain_create(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
3292                      hammer2_dev_t *hmp, hammer2_pfs_t *pmp, int methods,
3293                      hammer2_key_t key, int keybits, int type, size_t bytes,
3294                      hammer2_tid_t mtid, hammer2_off_t dedup_off, int flags)
3295 {
3296         hammer2_chain_t *chain;
3297         hammer2_chain_t *parent;
3298         hammer2_blockref_t *base;
3299         hammer2_blockref_t dummy;
3300         int allocated = 0;
3301         int error = 0;
3302         int count;
3303         int maxloops = 300000;
3304
3305         /*
3306          * Topology may be crossing a PFS boundary.
3307          */
3308         parent = *parentp;
3309         if (parent) {
3310                 KKASSERT(hammer2_mtx_owned(&parent->lock));
3311                 KKASSERT(parent->error == 0);
3312                 hmp = parent->hmp;
3313         }
3314         chain = *chainp;
3315
3316         if (chain == NULL) {
3317                 /*
3318                  * First allocate media space and construct the dummy bref,
3319                  * then allocate the in-memory chain structure.  Set the
3320                  * INITIAL flag for fresh chains which do not have embedded
3321                  * data.
3322                  *
3323                  * XXX for now set the check mode of the child based on
3324                  *     the parent or, if the parent is an inode, the
3325                  *     specification in the inode.
3326                  */
3327                 bzero(&dummy, sizeof(dummy));
3328                 dummy.type = type;
3329                 dummy.key = key;
3330                 dummy.keybits = keybits;
3331                 dummy.data_off = hammer2_getradix(bytes);
3332
3333                 /*
3334                  * Inherit methods from parent by default.  Primarily used
3335                  * for BREF_TYPE_DATA.  Non-data types *must* be set to
3336                  * a non-NONE check algorithm.
3337                  */
3338                 if (methods == -1)
3339                         dummy.methods = parent->bref.methods;
3340                 else
3341                         dummy.methods = (uint8_t)methods;
3342
3343                 if (type != HAMMER2_BREF_TYPE_DATA &&
3344                     HAMMER2_DEC_CHECK(dummy.methods) == HAMMER2_CHECK_NONE) {
3345                         dummy.methods |=
3346                                 HAMMER2_ENC_CHECK(HAMMER2_CHECK_DEFAULT);
3347                 }
3348
3349                 chain = hammer2_chain_alloc(hmp, pmp, &dummy);
3350
3351                 /*
3352                  * Lock the chain manually, chain_lock will load the chain
3353                  * which we do NOT want to do.  (note: chain->refs is set
3354                  * to 1 by chain_alloc() for us, but lockcnt is not).
3355                  */
3356                 chain->lockcnt = 1;
3357                 hammer2_mtx_ex(&chain->lock);
3358                 allocated = 1;
3359                 ++curthread->td_tracker;
3360
3361                 /*
3362                  * Set INITIAL to optimize I/O.  The flag will generally be
3363                  * processed when we call hammer2_chain_modify().
3364                  *
3365                  * Recalculate bytes to reflect the actual media block
3366                  * allocation.  Handle special case radix 0 == 0 bytes.
3367                  */
3368                 bytes = (size_t)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
3369                 if (bytes)
3370                         bytes = (hammer2_off_t)1 << bytes;
3371                 chain->bytes = bytes;
3372
3373                 switch(type) {
3374                 case HAMMER2_BREF_TYPE_VOLUME:
3375                 case HAMMER2_BREF_TYPE_FREEMAP:
3376                         panic("hammer2_chain_create: called with volume type");
3377                         break;
3378                 case HAMMER2_BREF_TYPE_INDIRECT:
3379                         panic("hammer2_chain_create: cannot be used to"
3380                               "create indirect block");
3381                         break;
3382                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3383                         panic("hammer2_chain_create: cannot be used to"
3384                               "create freemap root or node");
3385                         break;
3386                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3387                         KKASSERT(bytes == sizeof(chain->data->bmdata));
3388                         /* fall through */
3389                 case HAMMER2_BREF_TYPE_DIRENT:
3390                 case HAMMER2_BREF_TYPE_INODE:
3391                 case HAMMER2_BREF_TYPE_DATA:
3392                 default:
3393                         /*
3394                          * leave chain->data NULL, set INITIAL
3395                          */
3396                         KKASSERT(chain->data == NULL);
3397                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
3398                         break;
3399                 }
3400         } else {
3401                 /*
3402                  * We are reattaching a previously deleted chain, possibly
3403                  * under a new parent and possibly with a new key/keybits.
3404                  * The chain does not have to be in a modified state.  The
3405                  * UPDATE flag will be set later on in this routine.
3406                  *
3407                  * Do NOT mess with the current state of the INITIAL flag.
3408                  */
3409                 chain->bref.key = key;
3410                 chain->bref.keybits = keybits;
3411                 if (chain->flags & HAMMER2_CHAIN_DELETED)
3412                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3413                 KKASSERT(chain->parent == NULL);
3414         }
3415
3416         /*
3417          * Set the appropriate bref flag if requested.
3418          *
3419          * NOTE! Callers can call this function to move chains without
3420          *       knowing about special flags, so don't clear bref flags
3421          *       here!
3422          */
3423         if (flags & HAMMER2_INSERT_PFSROOT)
3424                 chain->bref.flags |= HAMMER2_BREF_FLAG_PFSROOT;
3425
3426         if (parent == NULL)
3427                 goto skip;
3428
3429         /*
3430          * Calculate how many entries we have in the blockref array and
3431          * determine if an indirect block is required when inserting into
3432          * the parent.
3433          */
3434 again:
3435         if (--maxloops == 0)
3436                 panic("hammer2_chain_create: maxloops");
3437
3438         switch(parent->bref.type) {
3439         case HAMMER2_BREF_TYPE_INODE:
3440                 if ((parent->data->ipdata.meta.op_flags &
3441                      HAMMER2_OPFLAG_DIRECTDATA) != 0) {
3442                         kprintf("hammer2: parent set for direct-data! "
3443                                 "pkey=%016jx ckey=%016jx\n",
3444                                 parent->bref.key,
3445                                 chain->bref.key);
3446                 }
3447                 KKASSERT((parent->data->ipdata.meta.op_flags &
3448                           HAMMER2_OPFLAG_DIRECTDATA) == 0);
3449                 KKASSERT(parent->data != NULL);
3450                 base = &parent->data->ipdata.u.blockset.blockref[0];
3451                 count = HAMMER2_SET_COUNT;
3452                 break;
3453         case HAMMER2_BREF_TYPE_INDIRECT:
3454         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3455                 if (parent->flags & HAMMER2_CHAIN_INITIAL)
3456                         base = NULL;
3457                 else
3458                         base = &parent->data->npdata[0];
3459                 count = parent->bytes / sizeof(hammer2_blockref_t);
3460                 break;
3461         case HAMMER2_BREF_TYPE_VOLUME:
3462                 KKASSERT(parent->data != NULL);
3463                 base = &parent->data->voldata.sroot_blockset.blockref[0];
3464                 count = HAMMER2_SET_COUNT;
3465                 break;
3466         case HAMMER2_BREF_TYPE_FREEMAP:
3467                 KKASSERT(parent->data != NULL);
3468                 base = &parent->data->blkset.blockref[0];
3469                 count = HAMMER2_SET_COUNT;
3470                 break;
3471         default:
3472                 panic("hammer2_chain_create: unrecognized blockref type: %d",
3473                       parent->bref.type);
3474                 base = NULL;
3475                 count = 0;
3476                 break;
3477         }
3478
3479         /*
3480          * Make sure we've counted the brefs
3481          */
3482         if ((parent->flags & HAMMER2_CHAIN_COUNTEDBREFS) == 0)
3483                 hammer2_chain_countbrefs(parent, base, count);
3484
3485         KASSERT(parent->core.live_count >= 0 &&
3486                 parent->core.live_count <= count,
3487                 ("bad live_count %d/%d (%02x, %d)",
3488                         parent->core.live_count, count,
3489                         parent->bref.type, parent->bytes));
3490
3491         /*
3492          * If no free blockref could be found we must create an indirect
3493          * block and move a number of blockrefs into it.  With the parent
3494          * locked we can safely lock each child in order to delete+duplicate
3495          * it without causing a deadlock.
3496          *
3497          * This may return the new indirect block or the old parent depending
3498          * on where the key falls.  NULL is returned on error.
3499          */
3500         if (parent->core.live_count == count) {
3501                 hammer2_chain_t *nparent;
3502
3503                 KKASSERT((flags & HAMMER2_INSERT_SAMEPARENT) == 0);
3504
3505                 nparent = hammer2_chain_create_indirect(parent, key, keybits,
3506                                                         mtid, type, &error);
3507                 if (nparent == NULL) {
3508                         if (allocated)
3509                                 hammer2_chain_drop(chain);
3510                         chain = NULL;
3511                         goto done;
3512                 }
3513                 if (parent != nparent) {
3514                         hammer2_chain_unlock(parent);
3515                         hammer2_chain_drop(parent);
3516                         parent = *parentp = nparent;
3517                 }
3518                 goto again;
3519         }
3520
3521         /*
3522          * fall through if parent, or skip to here if no parent.
3523          */
3524 skip:
3525         if (chain->flags & HAMMER2_CHAIN_DELETED)
3526                 kprintf("Inserting deleted chain @%016jx\n",
3527                         chain->bref.key);
3528
3529         /*
3530          * Link the chain into its parent.
3531          */
3532         if (chain->parent != NULL)
3533                 panic("hammer2: hammer2_chain_create: chain already connected");
3534         KKASSERT(chain->parent == NULL);
3535         if (parent) {
3536                 KKASSERT(parent->core.live_count < count);
3537                 hammer2_chain_insert(parent, chain,
3538                                      HAMMER2_CHAIN_INSERT_SPIN |
3539                                      HAMMER2_CHAIN_INSERT_LIVE,
3540                                      0);
3541         }
3542
3543         if (allocated) {
3544                 /*
3545                  * Mark the newly created chain modified.  This will cause
3546                  * UPDATE to be set and process the INITIAL flag.
3547                  *
3548                  * Device buffers are not instantiated for DATA elements
3549                  * as these are handled by logical buffers.
3550                  *
3551                  * Indirect and freemap node indirect blocks are handled
3552                  * by hammer2_chain_create_indirect() and not by this
3553                  * function.
3554                  *
3555                  * Data for all other bref types is expected to be
3556                  * instantiated (INODE, LEAF).
3557                  */
3558                 switch(chain->bref.type) {
3559                 case HAMMER2_BREF_TYPE_DATA:
3560                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
3561                 case HAMMER2_BREF_TYPE_DIRENT:
3562                 case HAMMER2_BREF_TYPE_INODE:
3563                         error = hammer2_chain_modify(chain, mtid, dedup_off,
3564                                                      HAMMER2_MODIFY_OPTDATA);
3565                         break;
3566                 default:
3567                         /*
3568                          * Remaining types are not supported by this function.
3569                          * In particular, INDIRECT and LEAF_NODE types are
3570                          * handled by create_indirect().
3571                          */
3572                         panic("hammer2_chain_create: bad type: %d",
3573                               chain->bref.type);
3574                         /* NOT REACHED */
3575                         break;
3576                 }
3577         } else {
3578                 /*
3579                  * When reconnecting a chain we must set UPDATE and
3580                  * setflush so the flush recognizes that it must update
3581                  * the bref in the parent.
3582                  */
3583                 if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0)
3584                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
3585         }
3586
3587         /*
3588          * We must setflush(parent) to ensure that it recurses through to
3589          * chain.  setflush(chain) might not work because ONFLUSH is possibly
3590          * already set in the chain (so it won't recurse up to set it in the
3591          * parent).
3592          */
3593         if (parent)
3594                 hammer2_chain_setflush(parent);
3595
3596 done:
3597         *chainp = chain;
3598
3599         return (error);
3600 }
3601
3602 /*
3603  * Move the chain from its old parent to a new parent.  The chain must have
3604  * already been deleted or already disconnected (or never associated) with
3605  * a parent.  The chain is reassociated with the new parent and the deleted
3606  * flag will be cleared (no longer deleted).  The chain's modification state
3607  * is not altered.
3608  *
3609  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (parent) TO THE INSERTION
3610  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
3611  * FULL.  This typically means that the caller is creating the chain after
3612  * doing a hammer2_chain_lookup().
3613  *
3614  * Neither (parent) or (chain) can be errored.
3615  *
3616  * If (parent) is non-NULL then the chain is inserted under the parent.
3617  *
3618  * If (parent) is NULL then the newly duplicated chain is not inserted
3619  * anywhere, similar to if it had just been chain_alloc()'d (suitable for
3620  * passing into hammer2_chain_create() after this function returns).
3621  *
3622  * WARNING! This function calls create which means it can insert indirect
3623  *          blocks.  This can cause other unrelated chains in the parent to
3624  *          be moved to a newly inserted indirect block in addition to the
3625  *          specific chain.
3626  */
3627 void
3628 hammer2_chain_rename(hammer2_chain_t **parentp, hammer2_chain_t *chain,
3629                      hammer2_tid_t mtid, int flags)
3630 {
3631         hammer2_blockref_t *bref;
3632         hammer2_dev_t *hmp;
3633         hammer2_chain_t *parent;
3634         size_t bytes;
3635
3636         /*
3637          * WARNING!  We should never resolve DATA to device buffers
3638          *           (XXX allow it if the caller did?), and since
3639          *           we currently do not have the logical buffer cache
3640          *           buffer in-hand to fix its cached physical offset
3641          *           we also force the modify code to not COW it. XXX
3642          *
3643          * NOTE!     We allow error'd chains to be renamed.  The bref itself
3644          *           is good and can be renamed.  The content, however, may
3645          *           be inaccessible.
3646          */
3647         hmp = chain->hmp;
3648         KKASSERT(chain->parent == NULL);
3649         /*KKASSERT(chain->error == 0); allow */
3650
3651         /*
3652          * Now create a duplicate of the chain structure, associating
3653          * it with the same core, making it the same size, pointing it
3654          * to the same bref (the same media block).
3655          *
3656          * NOTE: Handle special radix == 0 case (means 0 bytes).
3657          */
3658         bref = &chain->bref;
3659         bytes = (size_t)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
3660         if (bytes)
3661                 bytes = (hammer2_off_t)1 << bytes;
3662
3663         /*
3664          * If parent is not NULL the duplicated chain will be entered under
3665          * the parent and the UPDATE bit set to tell flush to update
3666          * the blockref.
3667          *
3668          * We must setflush(parent) to ensure that it recurses through to
3669          * chain.  setflush(chain) might not work because ONFLUSH is possibly
3670          * already set in the chain (so it won't recurse up to set it in the
3671          * parent).
3672          *
3673          * Having both chains locked is extremely important for atomicy.
3674          */
3675         if (parentp && (parent = *parentp) != NULL) {
3676                 KKASSERT(hammer2_mtx_owned(&parent->lock));
3677                 KKASSERT(parent->refs > 0);
3678                 KKASSERT(parent->error == 0);
3679
3680                 hammer2_chain_create(parentp, &chain, NULL, chain->pmp,
3681                                      HAMMER2_METH_DEFAULT,
3682                                      bref->key, bref->keybits, bref->type,
3683                                      chain->bytes, mtid, 0, flags);
3684                 KKASSERT(chain->flags & HAMMER2_CHAIN_UPDATE);
3685                 hammer2_chain_setflush(*parentp);
3686         }
3687 }
3688
3689 /*
3690  * This works in tandem with delete_obref() to install a blockref in
3691  * (typically) an indirect block that is associated with the chain being
3692  * moved to *parentp.
3693  *
3694  * The reason we need this function is that the caller needs to maintain
3695  * the blockref as it was, and not generate a new blockref for what might
3696  * be a modified chain.  Otherwise stuff will leak into the flush that
3697  * the flush code's FLUSH_INODE_STOP flag is unable to catch.
3698  *
3699  * It is EXTREMELY important that we properly set CHAIN_BMAPUPD and
3700  * CHAIN_UPDATE.  We must set BMAPUPD if the bref does not match, and
3701  * we must clear CHAIN_UPDATE (that was likely set by the chain_rename) if
3702  * it does.  Otherwise we can end up in a situation where H2 is unable to
3703  * clean up the in-memory chain topology.
3704  *
3705  * The reason for this is that flushes do not generally flush through
3706  * BREF_TYPE_INODE chains and depend on a hammer2_inode_t queued to syncq
3707  * or sideq to properly flush and dispose of the related inode chain's flags.
3708  * Situations where the inode is not actually modified by the frontend,
3709  * but where we have to move the related chains around as we insert or cleanup
3710  * indirect blocks, can leave us with a 'dirty' (non-disposable) in-memory
3711  * inode chain that does not have a hammer2_inode_t associated with it.
3712  */
3713 void
3714 hammer2_chain_rename_obref(hammer2_chain_t **parentp, hammer2_chain_t *chain,
3715                            hammer2_tid_t mtid, int flags,
3716                            hammer2_blockref_t *obref)
3717 {
3718         hammer2_chain_rename(parentp, chain, mtid, flags);
3719
3720         if (obref->type != HAMMER2_BREF_TYPE_EMPTY) {
3721                 hammer2_blockref_t *tbase;
3722                 int tcount;
3723
3724                 KKASSERT((chain->flags & HAMMER2_CHAIN_BMAPPED) == 0);
3725                 hammer2_chain_modify(*parentp, mtid, 0, 0);
3726                 tbase = hammer2_chain_base_and_count(*parentp, &tcount);
3727                 hammer2_base_insert(*parentp, tbase, tcount, chain, obref);
3728                 if (bcmp(obref, &chain->bref, sizeof(chain->bref))) {
3729                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPUPD |
3730                                                       HAMMER2_CHAIN_UPDATE);
3731                 } else {
3732                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
3733                 }
3734         }
3735 }
3736
3737 /*
3738  * Helper function for deleting chains.
3739  *
3740  * The chain is removed from the live view (the RBTREE) as well as the parent's
3741  * blockmap.  Both chain and its parent must be locked.
3742  *
3743  * parent may not be errored.  chain can be errored.
3744  */
3745 static int
3746 _hammer2_chain_delete_helper(hammer2_chain_t *parent, hammer2_chain_t *chain,
3747                              hammer2_tid_t mtid, int flags,
3748                              hammer2_blockref_t *obref)
3749 {
3750         hammer2_dev_t *hmp;
3751         int error = 0;
3752
3753         KKASSERT((chain->flags & (HAMMER2_CHAIN_DELETED |
3754                                   HAMMER2_CHAIN_FICTITIOUS)) == 0);
3755         KKASSERT(chain->parent == parent);
3756         hmp = chain->hmp;
3757
3758         if (chain->flags & HAMMER2_CHAIN_BMAPPED) {
3759                 /*
3760                  * Chain is blockmapped, so there must be a parent.
3761                  * Atomically remove the chain from the parent and remove
3762                  * the blockmap entry.  The parent must be set modified
3763                  * to remove the blockmap entry.
3764                  */
3765                 hammer2_blockref_t *base;
3766                 int count;
3767
3768                 KKASSERT(parent != NULL);
3769                 KKASSERT(parent->error == 0);
3770                 KKASSERT((parent->flags & HAMMER2_CHAIN_INITIAL) == 0);
3771                 error = hammer2_chain_modify(parent, mtid, 0, 0);
3772                 if (error)
3773                         goto done;
3774
3775                 /*
3776                  * Calculate blockmap pointer
3777                  */
3778                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
3779                 hammer2_spin_ex(&chain->core.spin);
3780                 hammer2_spin_ex(&parent->core.spin);
3781
3782                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3783                 atomic_add_int(&parent->core.live_count, -1);
3784                 ++parent->core.generation;
3785                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
3786                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
3787                 --parent->core.chain_count;
3788                 chain->parent = NULL;
3789
3790                 switch(parent->bref.type) {
3791                 case HAMMER2_BREF_TYPE_INODE:
3792                         /*
3793                          * Access the inode's block array.  However, there
3794                          * is no block array if the inode is flagged
3795                          * DIRECTDATA.
3796                          */
3797                         if (parent->data &&
3798                             (parent->data->ipdata.meta.op_flags &
3799                              HAMMER2_OPFLAG_DIRECTDATA) == 0) {
3800                                 base =
3801                                    &parent->data->ipdata.u.blockset.blockref[0];
3802                         } else {
3803                                 base = NULL;
3804                         }
3805                         count = HAMMER2_SET_COUNT;
3806                         break;
3807                 case HAMMER2_BREF_TYPE_INDIRECT:
3808                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
3809                         if (parent->data)
3810                                 base = &parent->data->npdata[0];
3811                         else
3812                                 base = NULL;
3813                         count = parent->bytes / sizeof(hammer2_blockref_t);
3814                         break;
3815                 case HAMMER2_BREF_TYPE_VOLUME:
3816                         base = &parent->data->voldata.
3817                                         sroot_blockset.blockref[0];
3818                         count = HAMMER2_SET_COUNT;
3819                         break;
3820                 case HAMMER2_BREF_TYPE_FREEMAP:
3821                         base = &parent->data->blkset.blockref[0];
3822                         count = HAMMER2_SET_COUNT;
3823                         break;
3824                 default:
3825                         base = NULL;
3826                         count = 0;
3827                         panic("_hammer2_chain_delete_helper: "
3828                               "unrecognized blockref type: %d",
3829                               parent->bref.type);
3830                 }
3831
3832                 /*
3833                  * delete blockmapped chain from its parent.
3834                  *
3835                  * The parent is not affected by any statistics in chain
3836                  * which are pending synchronization.  That is, there is
3837                  * nothing to undo in the parent since they have not yet
3838                  * been incorporated into the parent.
3839                  *
3840                  * The parent is affected by statistics stored in inodes.
3841                  * Those have already been synchronized, so they must be
3842                  * undone.  XXX split update possible w/delete in middle?
3843                  */
3844                 if (base) {
3845                         hammer2_base_delete(parent, base, count, chain, obref);
3846                 }
3847                 hammer2_spin_unex(&parent->core.spin);
3848                 hammer2_spin_unex(&chain->core.spin);
3849         } else if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
3850                 /*
3851                  * Chain is not blockmapped but a parent is present.
3852                  * Atomically remove the chain from the parent.  There is
3853                  * no blockmap entry to remove.
3854                  *
3855                  * Because chain was associated with a parent but not
3856                  * synchronized, the chain's *_count_up fields contain
3857                  * inode adjustment statistics which must be undone.
3858                  */
3859                 hammer2_spin_ex(&chain->core.spin);
3860                 hammer2_spin_ex(&parent->core.spin);
3861                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3862                 atomic_add_int(&parent->core.live_count, -1);
3863                 ++parent->core.generation;
3864                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
3865                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
3866                 --parent->core.chain_count;
3867                 chain->parent = NULL;
3868                 hammer2_spin_unex(&parent->core.spin);
3869                 hammer2_spin_unex(&chain->core.spin);
3870         } else {
3871                 /*
3872                  * Chain is not blockmapped and has no parent.  This
3873                  * is a degenerate case.
3874                  */
3875                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
3876         }
3877 done:
3878         return error;
3879 }
3880
3881 /*
3882  * Create an indirect block that covers one or more of the elements in the
3883  * current parent.  Either returns the existing parent with no locking or
3884  * ref changes or returns the new indirect block locked and referenced
3885  * and leaving the original parent lock/ref intact as well.
3886  *
3887  * If an error occurs, NULL is returned and *errorp is set to the H2 error.
3888  *
3889  * The returned chain depends on where the specified key falls.
3890  *
3891  * The key/keybits for the indirect mode only needs to follow three rules:
3892  *
3893  * (1) That all elements underneath it fit within its key space and
3894  *
3895  * (2) That all elements outside it are outside its key space.
3896  *
3897  * (3) When creating the new indirect block any elements in the current
3898  *     parent that fit within the new indirect block's keyspace must be
3899  *     moved into the new indirect block.
3900  *
3901  * (4) The keyspace chosen for the inserted indirect block CAN cover a wider
3902  *     keyspace the the current parent, but lookup/iteration rules will
3903  *     ensure (and must ensure) that rule (2) for all parents leading up
3904  *     to the nearest inode or the root volume header is adhered to.  This
3905  *     is accomplished by always recursing through matching keyspaces in
3906  *     the hammer2_chain_lookup() and hammer2_chain_next() API.
3907  *
3908  * The current implementation calculates the current worst-case keyspace by
3909  * iterating the current parent and then divides it into two halves, choosing
3910  * whichever half has the most elements (not necessarily the half containing
3911  * the requested key).
3912  *
3913  * We can also opt to use the half with the least number of elements.  This
3914  * causes lower-numbered keys (aka logical file offsets) to recurse through
3915  * fewer indirect blocks and higher-numbered keys to recurse through more.
3916  * This also has the risk of not moving enough elements to the new indirect
3917  * block and being forced to create several indirect blocks before the element
3918  * can be inserted.
3919  *
3920  * Must be called with an exclusively locked parent.
3921  *
3922  * NOTE: *errorp set to HAMMER_ERROR_* flags
3923  */
3924 static int hammer2_chain_indkey_freemap(hammer2_chain_t *parent,
3925                                 hammer2_key_t *keyp, int keybits,
3926                                 hammer2_blockref_t *base, int count);
3927 static int hammer2_chain_indkey_file(hammer2_chain_t *parent,
3928                                 hammer2_key_t *keyp, int keybits,
3929                                 hammer2_blockref_t *base, int count,
3930                                 int ncount);
3931 static int hammer2_chain_indkey_dir(hammer2_chain_t *parent,
3932                                 hammer2_key_t *keyp, int keybits,
3933                                 hammer2_blockref_t *base, int count,
3934                                 int ncount);
3935 static
3936 hammer2_chain_t *
3937 hammer2_chain_create_indirect(hammer2_chain_t *parent,
3938                               hammer2_key_t create_key, int create_bits,
3939                               hammer2_tid_t mtid, int for_type, int *errorp)
3940 {
3941         hammer2_dev_t *hmp;
3942         hammer2_blockref_t *base;
3943         hammer2_blockref_t *bref;
3944         hammer2_blockref_t bcopy;
3945         hammer2_blockref_t dummy;
3946         hammer2_chain_t *chain;
3947         hammer2_chain_t *ichain;
3948         hammer2_key_t key = create_key;
3949         hammer2_key_t key_beg;
3950         hammer2_key_t key_end;
3951         hammer2_key_t key_next;
3952         int keybits = create_bits;
3953         int count;
3954         int ncount;
3955         int nbytes;
3956         int loops;
3957         int error;
3958         int reason;
3959         int generation;
3960         int maxloops = 300000;
3961
3962         /*
3963          * Calculate the base blockref pointer or NULL if the chain
3964          * is known to be empty.  We need to calculate the array count
3965          * for RB lookups either way.
3966          */
3967         hmp = parent->hmp;
3968         KKASSERT(hammer2_mtx_owned(&parent->lock));
3969
3970         /*
3971          * Pre-modify the parent now to avoid having to deal with error
3972          * processing if we tried to later (in the middle of our loop).
3973          *
3974          * We are going to be moving bref's around, the indirect blocks
3975          * cannot be in an initial state.  Do not pass MODIFY_OPTDATA.
3976          */
3977         *errorp = hammer2_chain_modify(parent, mtid, 0, 0);
3978         if (*errorp) {
3979                 kprintf("hammer2_create_indirect: error %08x %s\n",
3980                         *errorp, hammer2_error_str(*errorp));
3981                 return NULL;
3982         }
3983         KKASSERT((parent->flags & HAMMER2_CHAIN_INITIAL) == 0);
3984
3985         /*hammer2_chain_modify(&parent, HAMMER2_MODIFY_OPTDATA);*/
3986         base = hammer2_chain_base_and_count(parent, &count);
3987
3988         /*
3989          * How big should our new indirect block be?  It has to be at least
3990          * as large as its parent for splits to work properly.
3991          *
3992          * The freemap uses a specific indirect block size.  The number of
3993          * levels are built dynamically and ultimately depend on the size
3994          * volume.  Because freemap blocks are taken from the reserved areas
3995          * of the volume our goal is efficiency (fewer levels) and not so
3996          * much to save disk space.
3997          *
3998          * The first indirect block level for a directory usually uses
3999          * HAMMER2_IND_BYTES_MIN (4KB = 32 directory entries).  Due to
4000          * the hash mechanism, this typically gives us a nominal
4001          * 32 * 4 entries with one level of indirection.
4002          *
4003          * We use HAMMER2_IND_BYTES_NOM (16KB = 128 blockrefs) for FILE
4004          * indirect blocks.  The initial 4 entries in the inode gives us
4005          * 256KB.  Up to 4 indirect blocks gives us 32MB.  Three levels
4006          * of indirection gives us 137GB, and so forth.  H2 can support
4007          * huge file sizes but they are not typical, so we try to stick
4008          * with compactness and do not use a larger indirect block size.
4009          *
4010          * We could use 64KB (PBUFSIZE), giving us 512 blockrefs, but
4011          * due to the way indirect blocks are created this usually winds
4012          * up being extremely inefficient for small files.  Even though
4013          * 16KB requires more levels of indirection for very large files,
4014          * the 16KB records can be ganged together into 64KB DIOs.
4015          */
4016         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
4017             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
4018                 nbytes = HAMMER2_FREEMAP_LEVELN_PSIZE;
4019         } else if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
4020                 if (parent->data->ipdata.meta.type ==
4021                     HAMMER2_OBJTYPE_DIRECTORY)
4022                         nbytes = HAMMER2_IND_BYTES_MIN; /* 4KB = 32 entries */
4023                 else
4024                         nbytes = HAMMER2_IND_BYTES_NOM; /* 16KB = ~8MB file */
4025
4026         } else {
4027                 nbytes = HAMMER2_IND_BYTES_NOM;
4028         }
4029         if (nbytes < count * sizeof(hammer2_blockref_t)) {
4030                 KKASSERT(for_type != HAMMER2_BREF_TYPE_FREEMAP_NODE &&
4031                          for_type != HAMMER2_BREF_TYPE_FREEMAP_LEAF);
4032                 nbytes = count * sizeof(hammer2_blockref_t);
4033         }
4034         ncount = nbytes / sizeof(hammer2_blockref_t);
4035
4036         /*
4037          * When creating an indirect block for a freemap node or leaf
4038          * the key/keybits must be fitted to static radix levels because
4039          * particular radix levels use particular reserved blocks in the
4040          * related zone.
4041          *
4042          * This routine calculates the key/radix of the indirect block
4043          * we need to create, and whether it is on the high-side or the
4044          * low-side.
4045          */
4046         switch(for_type) {
4047         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
4048         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
4049                 keybits = hammer2_chain_indkey_freemap(parent, &key, keybits,
4050                                                        base, count);
4051                 break;
4052         case HAMMER2_BREF_TYPE_DATA:
4053                 keybits = hammer2_chain_indkey_file(parent, &key, keybits,
4054                                                     base, count, ncount);
4055                 break;
4056         case HAMMER2_BREF_TYPE_DIRENT:
4057         case HAMMER2_BREF_TYPE_INODE:
4058                 keybits = hammer2_chain_indkey_dir(parent, &key, keybits,
4059                                                    base, count, ncount);
4060                 break;
4061         default:
4062                 panic("illegal indirect block for bref type %d", for_type);
4063                 break;
4064         }
4065
4066         /*
4067          * Normalize the key for the radix being represented, keeping the
4068          * high bits and throwing away the low bits.
4069          */
4070         key &= ~(((hammer2_key_t)1 << keybits) - 1);
4071
4072         /*
4073          * Ok, create our new indirect block
4074          */
4075         bzero(&dummy, sizeof(dummy));
4076         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
4077             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
4078                 dummy.type = HAMMER2_BREF_TYPE_FREEMAP_NODE;
4079         } else {
4080                 dummy.type = HAMMER2_BREF_TYPE_INDIRECT;
4081         }
4082         dummy.key = key;
4083         dummy.keybits = keybits;
4084         dummy.data_off = hammer2_getradix(nbytes);
4085         dummy.methods =
4086                 HAMMER2_ENC_CHECK(HAMMER2_DEC_CHECK(parent->bref.methods)) |
4087                 HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
4088
4089         ichain = hammer2_chain_alloc(hmp, parent->pmp, &dummy);
4090         atomic_set_int(&ichain->flags, HAMMER2_CHAIN_INITIAL);
4091         hammer2_chain_lock(ichain, HAMMER2_RESOLVE_MAYBE);
4092         /* ichain has one ref at this point */
4093
4094         /*
4095          * We have to mark it modified to allocate its block, but use
4096          * OPTDATA to allow it to remain in the INITIAL state.  Otherwise
4097          * it won't be acted upon by the flush code.
4098          *
4099          * XXX remove OPTDATA, we need a fully initialized indirect block to
4100          * be able to move the original blockref.
4101          */
4102         *errorp = hammer2_chain_modify(ichain, mtid, 0, 0);
4103         if (*errorp) {
4104                 kprintf("hammer2_alloc_indirect: error %08x %s\n",
4105                         *errorp, hammer2_error_str(*errorp));
4106                 hammer2_chain_unlock(ichain);
4107                 hammer2_chain_drop(ichain);
4108                 return NULL;
4109         }
4110         KKASSERT((ichain->flags & HAMMER2_CHAIN_INITIAL) == 0);
4111
4112         /*
4113          * Iterate the original parent and move the matching brefs into
4114          * the new indirect block.
4115          *
4116          * XXX handle flushes.
4117          */
4118         key_beg = 0;
4119         key_end = HAMMER2_KEY_MAX;
4120         key_next = 0;   /* avoid gcc warnings */
4121         hammer2_spin_ex(&parent->core.spin);
4122         loops = 0;
4123         reason = 0;
4124
4125         for (;;) {
4126                 /*
4127                  * Parent may have been modified, relocating its block array.
4128                  * Reload the base pointer.
4129                  */
4130                 base = hammer2_chain_base_and_count(parent, &count);
4131
4132                 if (++loops > 100000) {
4133                     hammer2_spin_unex(&parent->core.spin);
4134                     panic("excessive loops r=%d p=%p base/count %p:%d %016jx\n",
4135                           reason, parent, base, count, key_next);
4136                 }
4137
4138                 /*
4139                  * NOTE: spinlock stays intact, returned chain (if not NULL)
4140                  *       is not referenced or locked which means that we
4141                  *       cannot safely check its flagged / deletion status
4142                  *       until we lock it.
4143                  */
4144                 chain = hammer2_combined_find(parent, base, count,
4145                                               &key_next,
4146                                               key_beg, key_end,
4147                                               &bref);
4148                 generation = parent->core.generation;
4149                 if (bref == NULL)
4150                         break;
4151                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4152
4153                 /*
4154                  * Skip keys that are not within the key/radix of the new
4155                  * indirect block.  They stay in the parent.
4156                  */
4157                 if ((~(((hammer2_key_t)1 << keybits) - 1) &
4158                     (key ^ bref->key)) != 0) {
4159                         goto next_key_spinlocked;
4160                 }
4161
4162                 /*
4163                  * Load the new indirect block by acquiring the related
4164                  * chains (potentially from media as it might not be
4165                  * in-memory).  Then move it to the new parent (ichain).
4166                  *
4167                  * chain is referenced but not locked.  We must lock the
4168                  * chain to obtain definitive state.
4169                  */
4170                 bcopy = *bref;
4171                 if (chain) {
4172                         /*
4173                          * Use chain already present in the RBTREE
4174                          */
4175                         hammer2_chain_ref(chain);
4176                         hammer2_spin_unex(&parent->core.spin);
4177                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_NEVER);
4178                 } else {
4179                         /*
4180                          * Get chain for blockref element.  _get returns NULL
4181                          * on insertion race.
4182                          */
4183                         hammer2_spin_unex(&parent->core.spin);
4184                         chain = hammer2_chain_get(parent, generation, &bcopy,
4185                                                   HAMMER2_RESOLVE_NEVER);
4186                         if (chain == NULL) {
4187                                 reason = 1;
4188                                 hammer2_spin_ex(&parent->core.spin);
4189                                 continue;
4190                         }
4191                 }
4192
4193                 /*
4194                  * This is always live so if the chain has been deleted
4195                  * we raced someone and we have to retry.
4196                  *
4197                  * NOTE: Lookups can race delete-duplicate because
4198                  *       delete-duplicate does not lock the parent's core
4199                  *       (they just use the spinlock on the core).
4200                  *
4201                  *       (note reversed logic for this one)
4202                  */
4203                 if (bcmp(&bcopy, &chain->bref, sizeof(bcopy)) ||
4204                     chain->parent != parent ||
4205                     (chain->flags & HAMMER2_CHAIN_DELETED)) {
4206                         hammer2_chain_unlock(chain);
4207                         hammer2_chain_drop(chain);
4208                         if (hammer2_debug & 0x0040) {
4209                                 kprintf("LOST PARENT RETRY "
4210                                 "RETRY (%p,%p)->%p %08x\n",
4211                                 parent, chain->parent, chain, chain->flags);
4212                         }
4213                         hammer2_spin_ex(&parent->core.spin);
4214                         continue;
4215                 }
4216
4217                 /*
4218                  * Shift the chain to the indirect block.
4219                  *
4220                  * WARNING! No reason for us to load chain data, pass NOSTATS
4221                  *          to prevent delete/insert from trying to access
4222                  *          inode stats (and thus asserting if there is no
4223                  *          chain->data loaded).
4224                  *
4225                  * WARNING! The (parent, chain) deletion may modify the parent
4226                  *          and invalidate the base pointer.
4227                  *
4228                  * WARNING! Parent must already be marked modified, so we
4229                  *          can assume that chain_delete always suceeds.
4230                  *
4231                  * WARNING! hammer2_chain_repchange() does not have to be
4232                  *          called (and doesn't work anyway because we are
4233                  *          only doing a partial shift).  A recursion that is
4234                  *          in-progress can continue at the current parent
4235                  *          and will be able to properly find its next key.
4236                  */
4237                 error = hammer2_chain_delete_obref(parent, chain, mtid, 0,
4238                                                    &bcopy);
4239                 KKASSERT(error == 0);
4240                 hammer2_chain_rename_obref(&ichain, chain, mtid, 0, &bcopy);
4241                 hammer2_chain_unlock(chain);
4242                 hammer2_chain_drop(chain);
4243                 KKASSERT(parent->refs > 0);
4244                 chain = NULL;
4245                 base = NULL;    /* safety */
4246                 hammer2_spin_ex(&parent->core.spin);
4247 next_key_spinlocked:
4248                 if (--maxloops == 0)
4249                         panic("hammer2_chain_create_indirect: maxloops");
4250                 reason = 4;
4251                 if (key_next == 0 || key_next > key_end)
4252                         break;
4253                 key_beg = key_next;
4254                 /* loop */
4255         }
4256         hammer2_spin_unex(&parent->core.spin);
4257
4258         /*
4259          * Insert the new indirect block into the parent now that we've
4260          * cleared out some entries in the parent.  We calculated a good
4261          * insertion index in the loop above (ichain->index).
4262          *
4263          * We don't have to set UPDATE here because we mark ichain
4264          * modified down below (so the normal modified -> flush -> set-moved
4265          * sequence applies).
4266          *
4267          * The insertion shouldn't race as this is a completely new block
4268          * and the parent is locked.
4269          */
4270         base = NULL;    /* safety, parent modify may change address */
4271         KKASSERT((ichain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
4272         KKASSERT(parent->core.live_count < count);
4273         hammer2_chain_insert(parent, ichain,
4274                              HAMMER2_CHAIN_INSERT_SPIN |
4275                              HAMMER2_CHAIN_INSERT_LIVE,
4276                              0);
4277
4278         /*
4279          * Make sure flushes propogate after our manual insertion.
4280          */
4281         hammer2_chain_setflush(ichain);
4282         hammer2_chain_setflush(parent);
4283
4284         /*
4285          * Figure out what to return.
4286          */
4287         if (~(((hammer2_key_t)1 << keybits) - 1) &
4288                    (create_key ^ key)) {
4289                 /*
4290                  * Key being created is outside the key range,
4291                  * return the original parent.
4292                  */
4293                 hammer2_chain_unlock(ichain);
4294                 hammer2_chain_drop(ichain);
4295         } else {
4296                 /*
4297                  * Otherwise its in the range, return the new parent.
4298                  * (leave both the new and old parent locked).
4299                  */
4300                 parent = ichain;
4301         }
4302
4303         return(parent);
4304 }
4305
4306 /*
4307  * Do maintenance on an indirect chain.  Both parent and chain are locked.
4308  *
4309  * Returns non-zero if (chain) is deleted, either due to being empty or
4310  * because its children were safely moved into the parent.
4311  */
4312 int
4313 hammer2_chain_indirect_maintenance(hammer2_chain_t *parent,
4314                                    hammer2_chain_t *chain)
4315 {
4316         hammer2_blockref_t *chain_base;
4317         hammer2_blockref_t *base;
4318         hammer2_blockref_t *bref;
4319         hammer2_blockref_t bcopy;
4320         hammer2_key_t key_next;
4321         hammer2_key_t key_beg;
4322         hammer2_key_t key_end;
4323         hammer2_chain_t *sub;
4324         int chain_count;
4325         int count;
4326         int error;
4327         int generation;
4328
4329         /*
4330          * Make sure we have an accurate live_count
4331          */
4332         if ((chain->flags & (HAMMER2_CHAIN_INITIAL |
4333                              HAMMER2_CHAIN_COUNTEDBREFS)) == 0) {
4334                 base = &chain->data->npdata[0];
4335                 count = chain->bytes / sizeof(hammer2_blockref_t);
4336                 hammer2_chain_countbrefs(chain, base, count);
4337         }
4338
4339         /*
4340          * If the indirect block is empty we can delete it.
4341          * (ignore deletion error)
4342          */
4343         if (chain->core.live_count == 0 && RB_EMPTY(&chain->core.rbtree)) {
4344                 hammer2_chain_delete(parent, chain,
4345                                      chain->bref.modify_tid,
4346                                      HAMMER2_DELETE_PERMANENT);
4347                 hammer2_chain_repchange(parent, chain);
4348                 return 1;
4349         }
4350
4351         base = hammer2_chain_base_and_count(parent, &count);
4352
4353         if ((parent->flags & (HAMMER2_CHAIN_INITIAL |
4354                              HAMMER2_CHAIN_COUNTEDBREFS)) == 0) {
4355                 hammer2_chain_countbrefs(parent, base, count);
4356         }
4357
4358         /*
4359          * Determine if we can collapse chain into parent, calculate
4360          * hysteresis for chain emptiness.
4361          */
4362         if (parent->core.live_count + chain->core.live_count - 1 > count)
4363                 return 0;
4364         chain_count = chain->bytes / sizeof(hammer2_blockref_t);
4365         if (chain->core.live_count > chain_count * 3 / 4)
4366                 return 0;
4367
4368         /*
4369          * Ok, theoretically we can collapse chain's contents into
4370          * parent.  chain is locked, but any in-memory children of chain
4371          * are not.  For this to work, we must be able to dispose of any
4372          * in-memory children of chain.
4373          *
4374          * For now require that there are no in-memory children of chain.
4375          *
4376          * WARNING! Both chain and parent must remain locked across this
4377          *          entire operation.
4378          */
4379
4380         /*
4381          * Parent must be marked modified.  Don't try to collapse it if we
4382          * can't mark it modified.  Once modified, destroy chain to make room
4383          * and to get rid of what will be a conflicting key (this is included
4384          * in the calculation above).  Finally, move the children of chain
4385          * into chain's parent.
4386          *
4387          * This order creates an accounting problem for bref.embed.stats
4388          * because we destroy chain before we remove its children.  Any
4389          * elements whos blockref is already synchronized will be counted
4390          * twice.  To deal with the problem we clean out chain's stats prior
4391          * to deleting it.
4392          */
4393         error = hammer2_chain_modify(parent, 0, 0, 0);
4394         if (error) {
4395                 krateprintf(&krate_h2me, "hammer2: indirect_maint: %s\n",
4396                             hammer2_error_str(error));
4397                 return 0;
4398         }
4399         error = hammer2_chain_modify(chain, chain->bref.modify_tid, 0, 0);
4400         if (error) {
4401                 krateprintf(&krate_h2me, "hammer2: indirect_maint: %s\n",
4402                             hammer2_error_str(error));
4403                 return 0;
4404         }
4405
4406         chain->bref.embed.stats.inode_count = 0;
4407         chain->bref.embed.stats.data_count = 0;
4408         error = hammer2_chain_delete(parent, chain,
4409                                      chain->bref.modify_tid,
4410                                      HAMMER2_DELETE_PERMANENT);
4411         KKASSERT(error == 0);
4412
4413         /*
4414          * The combined_find call requires core.spin to be held.  One would
4415          * think there wouldn't be any conflicts since we hold chain
4416          * exclusively locked, but the caching mechanism for 0-ref children
4417          * does not require a chain lock.
4418          */
4419         hammer2_spin_ex(&chain->core.spin);
4420
4421         key_next = 0;
4422         key_beg = 0;
4423         key_end = HAMMER2_KEY_MAX;
4424         for (;;) {
4425                 chain_base = &chain->data->npdata[0];
4426                 chain_count = chain->bytes / sizeof(hammer2_blockref_t);
4427                 sub = hammer2_combined_find(chain, chain_base, chain_count,
4428                                             &key_next,
4429                                             key_beg, key_end,
4430                                             &bref);
4431                 generation = chain->core.generation;
4432                 if (bref == NULL)
4433                         break;
4434                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4435
4436                 bcopy = *bref;
4437                 if (sub) {
4438                         hammer2_chain_ref(sub);
4439                         hammer2_spin_unex(&chain->core.spin);
4440                         hammer2_chain_lock(sub, HAMMER2_RESOLVE_NEVER);
4441                 } else {
4442                         hammer2_spin_unex(&chain->core.spin);
4443                         sub = hammer2_chain_get(chain, generation, &bcopy,
4444                                                 HAMMER2_RESOLVE_NEVER);
4445                         if (sub == NULL) {
4446                                 hammer2_spin_ex(&chain->core.spin);
4447                                 continue;
4448                         }
4449                 }
4450                 if (bcmp(&bcopy, &sub->bref, sizeof(bcopy)) ||
4451                     sub->parent != chain ||
4452                     (sub->flags & HAMMER2_CHAIN_DELETED)) {
4453                         hammer2_chain_unlock(sub);
4454                         hammer2_chain_drop(sub);
4455                         hammer2_spin_ex(&chain->core.spin);
4456                         sub = NULL;     /* safety */
4457                         continue;
4458                 }
4459                 error = hammer2_chain_delete_obref(chain, sub,
4460                                                    sub->bref.modify_tid, 0,
4461                                                    &bcopy);
4462                 KKASSERT(error == 0);
4463                 hammer2_chain_rename_obref(&parent, sub,
4464                                      sub->bref.modify_tid,
4465                                      HAMMER2_INSERT_SAMEPARENT, &bcopy);
4466                 hammer2_chain_unlock(sub);
4467                 hammer2_chain_drop(sub);
4468                 hammer2_spin_ex(&chain->core.spin);
4469
4470                 if (key_next == 0)
4471                         break;
4472                 key_beg = key_next;
4473         }
4474         hammer2_spin_unex(&chain->core.spin);
4475
4476         hammer2_chain_repchange(parent, chain);
4477
4478         return 1;
4479 }
4480
4481 /*
4482  * Freemap indirect blocks
4483  *
4484  * Calculate the keybits and highside/lowside of the freemap node the
4485  * caller is creating.
4486  *
4487  * This routine will specify the next higher-level freemap key/radix
4488  * representing the lowest-ordered set.  By doing so, eventually all
4489  * low-ordered sets will be moved one level down.
4490  *
4491  * We have to be careful here because the freemap reserves a limited
4492  * number of blocks for a limited number of levels.  So we can't just
4493  * push indiscriminately.
4494  */
4495 int
4496 hammer2_chain_indkey_freemap(hammer2_chain_t *parent, hammer2_key_t *keyp,
4497                              int keybits, hammer2_blockref_t *base, int count)
4498 {
4499         hammer2_chain_t *chain;
4500         hammer2_blockref_t *bref;
4501         hammer2_key_t key;
4502         hammer2_key_t key_beg;
4503         hammer2_key_t key_end;
4504         hammer2_key_t key_next;
4505         int locount;
4506         int hicount;
4507         int maxloops = 300000;
4508
4509         key = *keyp;
4510         locount = 0;
4511         hicount = 0;
4512         keybits = 64;
4513
4514         /*
4515          * Calculate the range of keys in the array being careful to skip
4516          * slots which are overridden with a deletion.
4517          */
4518         key_beg = 0;
4519         key_end = HAMMER2_KEY_MAX;
4520         hammer2_spin_ex(&parent->core.spin);
4521
4522         for (;;) {
4523                 if (--maxloops == 0) {
4524                         panic("indkey_freemap shit %p %p:%d\n",
4525                               parent, base, count);
4526                 }
4527                 chain = hammer2_combined_find(parent, base, count,
4528                                               &key_next,
4529                                               key_beg, key_end,
4530                                               &bref);
4531
4532                 /*
4533                  * Exhausted search
4534                  */
4535                 if (bref == NULL)
4536                         break;
4537
4538                 /*
4539                  * Skip deleted chains.
4540                  */
4541                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4542                         if (key_next == 0 || key_next > key_end)
4543                                 break;
4544                         key_beg = key_next;
4545                         continue;
4546                 }
4547
4548                 /*
4549                  * Use the full live (not deleted) element for the scan
4550                  * iteration.  HAMMER2 does not allow partial replacements.
4551                  *
4552                  * XXX should be built into hammer2_combined_find().
4553                  */
4554                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4555
4556                 if (keybits > bref->keybits) {
4557                         key = bref->key;
4558                         keybits = bref->keybits;
4559                 } else if (keybits == bref->keybits && bref->key < key) {
4560                         key = bref->key;
4561                 }
4562                 if (key_next == 0)
4563                         break;
4564                 key_beg = key_next;
4565         }
4566         hammer2_spin_unex(&parent->core.spin);
4567
4568         /*
4569          * Return the keybits for a higher-level FREEMAP_NODE covering
4570          * this node.
4571          */
4572         switch(keybits) {
4573         case HAMMER2_FREEMAP_LEVEL0_RADIX:
4574                 keybits = HAMMER2_FREEMAP_LEVEL1_RADIX;
4575                 break;
4576         case HAMMER2_FREEMAP_LEVEL1_RADIX:
4577                 keybits = HAMMER2_FREEMAP_LEVEL2_RADIX;
4578                 break;
4579         case HAMMER2_FREEMAP_LEVEL2_RADIX:
4580                 keybits = HAMMER2_FREEMAP_LEVEL3_RADIX;
4581                 break;
4582         case HAMMER2_FREEMAP_LEVEL3_RADIX:
4583                 keybits = HAMMER2_FREEMAP_LEVEL4_RADIX;
4584                 break;
4585         case HAMMER2_FREEMAP_LEVEL4_RADIX:
4586                 keybits = HAMMER2_FREEMAP_LEVEL5_RADIX;
4587                 break;
4588         case HAMMER2_FREEMAP_LEVEL5_RADIX:
4589                 panic("hammer2_chain_indkey_freemap: level too high");
4590                 break;
4591         default:
4592                 panic("hammer2_chain_indkey_freemap: bad radix");
4593                 break;
4594         }
4595         *keyp = key;
4596
4597         return (keybits);
4598 }
4599
4600 /*
4601  * File indirect blocks
4602  *
4603  * Calculate the key/keybits for the indirect block to create by scanning
4604  * existing keys.  The key being created is also passed in *keyp and can be
4605  * inside or outside the indirect block.  Regardless, the indirect block
4606  * must hold at least two keys in order to guarantee sufficient space.
4607  *
4608  * We use a modified version of the freemap's fixed radix tree, but taylored
4609  * for file data.  Basically we configure an indirect block encompassing the
4610  * smallest key.
4611  */
4612 static int
4613 hammer2_chain_indkey_file(hammer2_chain_t *parent, hammer2_key_t *keyp,
4614                             int keybits, hammer2_blockref_t *base, int count,
4615                             int ncount)
4616 {
4617         hammer2_chain_t *chain;
4618         hammer2_blockref_t *bref;
4619         hammer2_key_t key;
4620         hammer2_key_t key_beg;
4621         hammer2_key_t key_end;
4622         hammer2_key_t key_next;
4623         int nradix;
4624         int locount;
4625         int hicount;
4626         int maxloops = 300000;
4627
4628         key = *keyp;
4629         locount = 0;
4630         hicount = 0;
4631         keybits = 64;
4632
4633         /*
4634          * Calculate the range of keys in the array being careful to skip
4635          * slots which are overridden with a deletion.
4636          *
4637          * Locate the smallest key.
4638          */
4639         key_beg = 0;
4640         key_end = HAMMER2_KEY_MAX;
4641         hammer2_spin_ex(&parent->core.spin);
4642
4643         for (;;) {
4644                 if (--maxloops == 0) {
4645                         panic("indkey_freemap shit %p %p:%d\n",
4646                               parent, base, count);
4647                 }
4648                 chain = hammer2_combined_find(parent, base, count,
4649                                               &key_next,
4650                                               key_beg, key_end,
4651                                               &bref);
4652
4653                 /*
4654                  * Exhausted search
4655                  */
4656                 if (bref == NULL)
4657                         break;
4658
4659                 /*
4660                  * Skip deleted chains.
4661                  */
4662                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4663                         if (key_next == 0 || key_next > key_end)
4664                                 break;
4665                         key_beg = key_next;
4666                         continue;
4667                 }
4668
4669                 /*
4670                  * Use the full live (not deleted) element for the scan
4671                  * iteration.  HAMMER2 does not allow partial replacements.
4672                  *
4673                  * XXX should be built into hammer2_combined_find().
4674                  */
4675                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4676
4677                 if (keybits > bref->keybits) {
4678                         key = bref->key;
4679                         keybits = bref->keybits;
4680                 } else if (keybits == bref->keybits && bref->key < key) {
4681                         key = bref->key;
4682                 }
4683                 if (key_next == 0)
4684                         break;
4685                 key_beg = key_next;
4686         }
4687         hammer2_spin_unex(&parent->core.spin);
4688
4689         /*
4690          * Calculate the static keybits for a higher-level indirect block
4691          * that contains the key.
4692          */
4693         *keyp = key;
4694
4695         switch(ncount) {
4696         case HAMMER2_IND_BYTES_MIN / sizeof(hammer2_blockref_t):
4697                 nradix = HAMMER2_IND_RADIX_MIN - HAMMER2_BLOCKREF_RADIX;
4698                 break;
4699         case HAMMER2_IND_BYTES_NOM / sizeof(hammer2_blockref_t):
4700                 nradix = HAMMER2_IND_RADIX_NOM - HAMMER2_BLOCKREF_RADIX;
4701                 break;
4702         case HAMMER2_IND_BYTES_MAX / sizeof(hammer2_blockref_t):
4703                 nradix = HAMMER2_IND_RADIX_MAX - HAMMER2_BLOCKREF_RADIX;
4704                 break;
4705         default:
4706                 panic("bad ncount %d\n", ncount);
4707                 nradix = 0;
4708                 break;
4709         }
4710
4711         /*
4712          * The largest radix that can be returned for an indirect block is
4713          * 63 bits.  (The largest practical indirect block radix is actually
4714          * 62 bits because the top-level inode or volume root contains four
4715          * entries, but allow 63 to be returned).
4716          */
4717         if (nradix >= 64)
4718                 nradix = 63;
4719
4720         return keybits + nradix;
4721 }
4722
4723 #if 1
4724
4725 /*
4726  * Directory indirect blocks.
4727  *
4728  * Covers both the inode index (directory of inodes), and directory contents
4729  * (filenames hardlinked to inodes).
4730  *
4731  * Because directory keys are hashed we generally try to cut the space in
4732  * half.  We accomodate the inode index (which tends to have linearly
4733  * increasing inode numbers) by ensuring that the keyspace is at least large
4734  * enough to fill up the indirect block being created.
4735  */
4736 static int
4737 hammer2_chain_indkey_dir(hammer2_chain_t *parent, hammer2_key_t *keyp,
4738                          int keybits, hammer2_blockref_t *base, int count,
4739                          int ncount)
4740 {
4741         hammer2_blockref_t *bref;
4742         hammer2_chain_t *chain;
4743         hammer2_key_t key_beg;
4744         hammer2_key_t key_end;
4745         hammer2_key_t key_next;
4746         hammer2_key_t key;
4747         int nkeybits;
4748         int locount;
4749         int hicount;
4750         int maxloops = 300000;
4751
4752         /*
4753          * NOTE: We can't take a shortcut here anymore for inodes because
4754          *       the root directory can contain a mix of inodes and directory
4755          *       entries (we used to just return 63 if parent->bref.type was
4756          *       HAMMER2_BREF_TYPE_INODE.
4757          */
4758         key = *keyp;
4759         locount = 0;
4760         hicount = 0;
4761
4762         /*
4763          * Calculate the range of keys in the array being careful to skip
4764          * slots which are overridden with a deletion.
4765          */
4766         key_beg = 0;
4767         key_end = HAMMER2_KEY_MAX;
4768         hammer2_spin_ex(&parent->core.spin);
4769
4770         for (;;) {
4771                 if (--maxloops == 0) {
4772                         panic("indkey_freemap shit %p %p:%d\n",
4773                               parent, base, count);
4774                 }
4775                 chain = hammer2_combined_find(parent, base, count,
4776                                               &key_next,
4777                                               key_beg, key_end,
4778                                               &bref);
4779
4780                 /*
4781                  * Exhausted search
4782                  */
4783                 if (bref == NULL)
4784                         break;
4785
4786                 /*
4787                  * Deleted object
4788                  */
4789                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4790                         if (key_next == 0 || key_next > key_end)
4791                                 break;
4792                         key_beg = key_next;
4793                         continue;
4794                 }
4795
4796                 /*
4797                  * Use the full live (not deleted) element for the scan
4798                  * iteration.  HAMMER2 does not allow partial replacements.
4799                  *
4800                  * XXX should be built into hammer2_combined_find().
4801                  */
4802                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4803
4804                 /*
4805                  * Expand our calculated key range (key, keybits) to fit
4806                  * the scanned key.  nkeybits represents the full range
4807                  * that we will later cut in half (two halves @ nkeybits - 1).
4808                  */
4809                 nkeybits = keybits;
4810                 if (nkeybits < bref->keybits) {
4811                         if (bref->keybits > 64) {
4812                                 kprintf("bad bref chain %p bref %p\n",
4813                                         chain, bref);
4814                                 Debugger("fubar");
4815                         }
4816                         nkeybits = bref->keybits;
4817                 }
4818                 while (nkeybits < 64 &&
4819                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
4820                         (key ^ bref->key)) != 0) {
4821                         ++nkeybits;
4822                 }
4823
4824                 /*
4825                  * If the new key range is larger we have to determine
4826                  * which side of the new key range the existing keys fall
4827                  * under by checking the high bit, then collapsing the
4828                  * locount into the hicount or vise-versa.
4829                  */
4830                 if (keybits != nkeybits) {
4831                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
4832                                 hicount += locount;
4833                                 locount = 0;
4834                         } else {
4835                                 locount += hicount;
4836                                 hicount = 0;
4837                         }
4838                         keybits = nkeybits;
4839                 }
4840
4841                 /*
4842                  * The newly scanned key will be in the lower half or the
4843                  * upper half of the (new) key range.
4844                  */
4845                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
4846                         ++hicount;
4847                 else
4848                         ++locount;
4849
4850                 if (key_next == 0)
4851                         break;
4852                 key_beg = key_next;
4853         }
4854         hammer2_spin_unex(&parent->core.spin);
4855         bref = NULL;    /* now invalid (safety) */
4856
4857         /*
4858          * Adjust keybits to represent half of the full range calculated
4859          * above (radix 63 max) for our new indirect block.
4860          */
4861         --keybits;
4862
4863         /*
4864          * Expand keybits to hold at least ncount elements.  ncount will be
4865          * a power of 2.  This is to try to completely fill leaf nodes (at
4866          * least for keys which are not hashes).
4867          *
4868          * We aren't counting 'in' or 'out', we are counting 'high side'
4869          * and 'low side' based on the bit at (1LL << keybits).  We want
4870          * everything to be inside in these cases so shift it all to
4871          * the low or high side depending on the new high bit.
4872          */
4873         while (((hammer2_key_t)1 << keybits) < ncount) {
4874                 ++keybits;
4875                 if (key & ((hammer2_key_t)1 << keybits)) {
4876                         hicount += locount;
4877                         locount = 0;
4878                 } else {
4879                         locount += hicount;
4880                         hicount = 0;
4881                 }
4882         }
4883
4884         if (hicount > locount)
4885                 key |= (hammer2_key_t)1 << keybits;
4886         else
4887                 key &= ~(hammer2_key_t)1 << keybits;
4888
4889         *keyp = key;
4890
4891         return (keybits);
4892 }
4893
4894 #else
4895
4896 /*
4897  * Directory indirect blocks.
4898  *
4899  * Covers both the inode index (directory of inodes), and directory contents
4900  * (filenames hardlinked to inodes).
4901  *
4902  * Because directory keys are hashed we generally try to cut the space in
4903  * half.  We accomodate the inode index (which tends to have linearly
4904  * increasing inode numbers) by ensuring that the keyspace is at least large
4905  * enough to fill up the indirect block being created.
4906  */
4907 static int
4908 hammer2_chain_indkey_dir(hammer2_chain_t *parent, hammer2_key_t *keyp,
4909                          int keybits, hammer2_blockref_t *base, int count,
4910                          int ncount)
4911 {
4912         hammer2_blockref_t *bref;
4913         hammer2_chain_t *chain;
4914         hammer2_key_t key_beg;
4915         hammer2_key_t key_end;
4916         hammer2_key_t key_next;
4917         hammer2_key_t key;
4918         int nkeybits;
4919         int locount;
4920         int hicount;
4921         int maxloops = 300000;
4922
4923         /*
4924          * Shortcut if the parent is the inode.  In this situation the
4925          * parent has 4+1 directory entries and we are creating an indirect
4926          * block capable of holding many more.
4927          */
4928         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
4929                 return 63;
4930         }
4931
4932         key = *keyp;
4933         locount = 0;
4934         hicount = 0;
4935
4936         /*
4937          * Calculate the range of keys in the array being careful to skip
4938          * slots which are overridden with a deletion.
4939          */
4940         key_beg = 0;
4941         key_end = HAMMER2_KEY_MAX;
4942         hammer2_spin_ex(&parent->core.spin);
4943
4944         for (;;) {
4945                 if (--maxloops == 0) {
4946                         panic("indkey_freemap shit %p %p:%d\n",
4947                               parent, base, count);
4948                 }
4949                 chain = hammer2_combined_find(parent, base, count,
4950                                               &key_next,
4951                                               key_beg, key_end,
4952                                               &bref);
4953
4954                 /*
4955                  * Exhausted search
4956                  */
4957                 if (bref == NULL)
4958                         break;
4959
4960                 /*
4961                  * Deleted object
4962                  */
4963                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
4964                         if (key_next == 0 || key_next > key_end)
4965                                 break;
4966                         key_beg = key_next;
4967                         continue;
4968                 }
4969
4970                 /*
4971                  * Use the full live (not deleted) element for the scan
4972                  * iteration.  HAMMER2 does not allow partial replacements.
4973                  *
4974                  * XXX should be built into hammer2_combined_find().
4975                  */
4976                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
4977
4978                 /*
4979                  * Expand our calculated key range (key, keybits) to fit
4980                  * the scanned key.  nkeybits represents the full range
4981                  * that we will later cut in half (two halves @ nkeybits - 1).
4982                  */
4983                 nkeybits = keybits;
4984                 if (nkeybits < bref->keybits) {
4985                         if (bref->keybits > 64) {
4986                                 kprintf("bad bref chain %p bref %p\n",
4987                                         chain, bref);
4988                                 Debugger("fubar");
4989                         }
4990                         nkeybits = bref->keybits;
4991                 }
4992                 while (nkeybits < 64 &&
4993                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
4994                         (key ^ bref->key)) != 0) {
4995                         ++nkeybits;
4996                 }
4997
4998                 /*
4999                  * If the new key range is larger we have to determine
5000                  * which side of the new key range the existing keys fall
5001                  * under by checking the high bit, then collapsing the
5002                  * locount into the hicount or vise-versa.
5003                  */
5004                 if (keybits != nkeybits) {
5005                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
5006                                 hicount += locount;
5007                                 locount = 0;
5008                         } else {
5009                                 locount += hicount;
5010                                 hicount = 0;
5011                         }
5012                         keybits = nkeybits;
5013                 }
5014
5015                 /*
5016                  * The newly scanned key will be in the lower half or the
5017                  * upper half of the (new) key range.
5018                  */
5019                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
5020                         ++hicount;
5021                 else
5022                         ++locount;
5023
5024                 if (key_next == 0)
5025                         break;
5026                 key_beg = key_next;
5027         }
5028         hammer2_spin_unex(&parent->core.spin);
5029         bref = NULL;    /* now invalid (safety) */
5030
5031         /*
5032          * Adjust keybits to represent half of the full range calculated
5033          * above (radix 63 max) for our new indirect block.
5034          */
5035         --keybits;
5036
5037         /*
5038          * Expand keybits to hold at least ncount elements.  ncount will be
5039          * a power of 2.  This is to try to completely fill leaf nodes (at
5040          * least for keys which are not hashes).
5041          *
5042          * We aren't counting 'in' or 'out', we are counting 'high side'
5043          * and 'low side' based on the bit at (1LL << keybits).  We want
5044          * everything to be inside in these cases so shift it all to
5045          * the low or high side depending on the new high bit.
5046          */
5047         while (((hammer2_key_t)1 << keybits) < ncount) {
5048                 ++keybits;
5049                 if (key & ((hammer2_key_t)1 << keybits)) {
5050                         hicount += locount;
5051                         locount = 0;
5052                 } else {
5053                         locount += hicount;
5054                         hicount = 0;
5055                 }
5056         }
5057
5058         if (hicount > locount)
5059                 key |= (hammer2_key_t)1 << keybits;
5060         else
5061                 key &= ~(hammer2_key_t)1 << keybits;
5062
5063         *keyp = key;
5064
5065         return (keybits);
5066 }
5067
5068 #endif
5069
5070 /*
5071  * Sets CHAIN_DELETED and remove the chain's blockref from the parent if
5072  * it exists.
5073  *
5074  * Both parent and chain must be locked exclusively.
5075  *
5076  * This function will modify the parent if the blockref requires removal
5077  * from the parent's block table.
5078  *
5079  * This function is NOT recursive.  Any entity already pushed into the
5080  * chain (such as an inode) may still need visibility into its contents,
5081  * as well as the ability to read and modify the contents.  For example,
5082  * for an unlinked file which is still open.
5083  *
5084  * Also note that the flusher is responsible for cleaning up empty
5085  * indirect blocks.
5086  */
5087 int
5088 hammer2_chain_delete(hammer2_chain_t *parent, hammer2_chain_t *chain,
5089                      hammer2_tid_t mtid, int flags)
5090 {
5091         int error = 0;
5092
5093         KKASSERT(hammer2_mtx_owned(&chain->lock));
5094
5095         /*
5096          * Nothing to do if already marked.
5097          *
5098          * We need the spinlock on the core whos RBTREE contains chain
5099          * to protect against races.
5100          */
5101         if ((chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
5102                 KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0 &&
5103                          chain->parent == parent);
5104                 error = _hammer2_chain_delete_helper(parent, chain,
5105                                                      mtid, flags, NULL);
5106         }
5107
5108         /*
5109          * Permanent deletions mark the chain as destroyed.
5110          *
5111          * NOTE: We do not setflush the chain unless the deletion is
5112          *       permanent, since the deletion of a chain does not actually
5113          *       require it to be flushed.
5114          */
5115         if (error == 0) {
5116                 if (flags & HAMMER2_DELETE_PERMANENT) {
5117                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
5118                         hammer2_chain_setflush(chain);
5119                 }
5120         }
5121
5122         return error;
5123 }
5124
5125 static int
5126 hammer2_chain_delete_obref(hammer2_chain_t *parent, hammer2_chain_t *chain,
5127                      hammer2_tid_t mtid, int flags,
5128                      hammer2_blockref_t *obref)
5129 {
5130         int error = 0;
5131
5132         KKASSERT(hammer2_mtx_owned(&chain->lock));
5133
5134         /*
5135          * Nothing to do if already marked.
5136          *
5137          * We need the spinlock on the core whos RBTREE contains chain
5138          * to protect against races.
5139          */
5140         obref->type = HAMMER2_BREF_TYPE_EMPTY;
5141         if ((chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
5142                 KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0 &&
5143                          chain->parent == parent);
5144                 error = _hammer2_chain_delete_helper(parent, chain,
5145                                                      mtid, flags, obref);
5146         }
5147
5148         /*
5149          * Permanent deletions mark the chain as destroyed.
5150          *
5151          * NOTE: We do not setflush the chain unless the deletion is
5152          *       permanent, since the deletion of a chain does not actually
5153          *       require it to be flushed.
5154          */
5155         if (error == 0) {
5156                 if (flags & HAMMER2_DELETE_PERMANENT) {
5157                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
5158                         hammer2_chain_setflush(chain);
5159                 }
5160         }
5161
5162         return error;
5163 }
5164
5165 /*
5166  * Returns the index of the nearest element in the blockref array >= elm.
5167  * Returns (count) if no element could be found.
5168  *
5169  * Sets *key_nextp to the next key for loop purposes but does not modify
5170  * it if the next key would be higher than the current value of *key_nextp.
5171  * Note that *key_nexp can overflow to 0, which should be tested by the
5172  * caller.
5173  *
5174  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
5175  *           held through the operation.
5176  */
5177 static int
5178 hammer2_base_find(hammer2_chain_t *parent,
5179                   hammer2_blockref_t *base, int count,
5180                   hammer2_key_t *key_nextp,
5181                   hammer2_key_t key_beg, hammer2_key_t key_end)
5182 {
5183         hammer2_blockref_t *scan;
5184         hammer2_key_t scan_end;
5185         int i;
5186         int limit;
5187
5188         /*
5189          * Require the live chain's already have their core's counted
5190          * so we can optimize operations.
5191          */
5192         KKASSERT(parent->flags & HAMMER2_CHAIN_COUNTEDBREFS);
5193
5194         /*
5195          * Degenerate case
5196          */
5197         if (count == 0 || base == NULL)
5198                 return(count);
5199
5200         /*
5201          * Sequential optimization using parent->cache_index.  This is
5202          * the most likely scenario.
5203          *
5204          * We can avoid trailing empty entries on live chains, otherwise
5205          * we might have to check the whole block array.
5206          */
5207         i = parent->cache_index;        /* SMP RACE OK */
5208         cpu_ccfence();
5209         limit = parent->core.live_zero;
5210         if (i >= limit)
5211                 i = limit - 1;
5212         if (i < 0)
5213                 i = 0;
5214         KKASSERT(i < count);
5215
5216         /*
5217          * Search backwards
5218          */
5219         scan = &base[i];
5220         while (i > 0 && (scan->type == HAMMER2_BREF_TYPE_EMPTY ||
5221             scan->key > key_beg)) {
5222                 --scan;
5223                 --i;
5224         }
5225         parent->cache_index = i;
5226
5227         /*
5228          * Search forwards, stop when we find a scan element which
5229          * encloses the key or until we know that there are no further
5230          * elements.
5231          */
5232         while (i < count) {
5233                 if (scan->type != HAMMER2_BREF_TYPE_EMPTY) {
5234                         scan_end = scan->key +
5235                                    ((hammer2_key_t)1 << scan->keybits) - 1;
5236                         if (scan->key > key_beg || scan_end >= key_beg)
5237                                 break;
5238                 }
5239                 if (i >= limit)
5240                         return (count);
5241                 ++scan;
5242                 ++i;
5243         }
5244         if (i != count) {
5245                 parent->cache_index = i;
5246                 if (i >= limit) {
5247                         i = count;
5248                 } else {
5249                         scan_end = scan->key +
5250                                    ((hammer2_key_t)1 << scan->keybits);
5251                         if (scan_end && (*key_nextp > scan_end ||
5252                                          *key_nextp == 0)) {
5253                                 *key_nextp = scan_end;
5254                         }
5255                 }
5256         }
5257         return (i);
5258 }
5259
5260 /*
5261  * Do a combined search and return the next match either from the blockref
5262  * array or from the in-memory chain.  Sets *bresp to the returned bref in
5263  * both cases, or sets it to NULL if the search exhausted.  Only returns
5264  * a non-NULL chain if the search matched from the in-memory chain.
5265  *
5266  * When no in-memory chain has been found and a non-NULL bref is returned
5267  * in *bresp.
5268  *
5269  *
5270  * The returned chain is not locked or referenced.  Use the returned bref
5271  * to determine if the search exhausted or not.  Iterate if the base find
5272  * is chosen but matches a deleted chain.
5273  *
5274  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
5275  *           held through the operation.
5276  */
5277 hammer2_chain_t *
5278 hammer2_combined_find(hammer2_chain_t *parent,
5279                       hammer2_blockref_t *base, int count,
5280                       hammer2_key_t *key_nextp,
5281                       hammer2_key_t key_beg, hammer2_key_t key_end,
5282                       hammer2_blockref_t **bresp)
5283 {
5284         hammer2_blockref_t *bref;
5285         hammer2_chain_t *chain;
5286         int i;
5287
5288         /*
5289          * Lookup in block array and in rbtree.
5290          */
5291         *key_nextp = key_end + 1;
5292         i = hammer2_base_find(parent, base, count, key_nextp,
5293                               key_beg, key_end);
5294         chain = hammer2_chain_find(parent, key_nextp, key_beg, key_end);
5295
5296         /*
5297          * Neither matched
5298          */
5299         if (i == count && chain == NULL) {
5300                 *bresp = NULL;
5301                 return(NULL);
5302         }
5303
5304         /*
5305          * Only chain matched.
5306          */
5307         if (i == count) {
5308                 bref = &chain->bref;
5309                 goto found;
5310         }
5311
5312         /*
5313          * Only blockref matched.
5314          */
5315         if (chain == NULL) {
5316                 bref = &base[i];
5317                 goto found;
5318         }
5319
5320         /*
5321          * Both in-memory and blockref matched, select the nearer element.
5322          *
5323          * If both are flush with the left-hand side or both are the
5324          * same distance away, select the chain.  In this situation the
5325          * chain must have been loaded from the matching blockmap.
5326          */
5327         if ((chain->bref.key <= key_beg && base[i].key <= key_beg) ||
5328             chain->bref.key == base[i].key) {
5329                 KKASSERT(chain->bref.key == base[i].key);
5330                 bref = &chain->bref;
5331                 goto found;
5332         }
5333
5334         /*
5335          * Select the nearer key
5336          */
5337         if (chain->bref.key < base[i].key) {
5338                 bref = &chain->bref;
5339         } else {
5340                 bref = &base[i];
5341                 chain = NULL;
5342         }
5343
5344         /*
5345          * If the bref is out of bounds we've exhausted our search.
5346          */
5347 found:
5348         if (bref->key > key_end) {
5349                 *bresp = NULL;
5350                 chain = NULL;
5351         } else {
5352                 *bresp = bref;
5353         }
5354         return(chain);
5355 }
5356
5357 /*
5358  * Locate the specified block array element and delete it.  The element
5359  * must exist.
5360  *
5361  * The spin lock on the related chain must be held.
5362  *
5363  * NOTE: live_count was adjusted when the chain was deleted, so it does not
5364  *       need to be adjusted when we commit the media change.
5365  */
5366 void
5367 hammer2_base_delete(hammer2_chain_t *parent,
5368                     hammer2_blockref_t *base, int count,
5369                     hammer2_chain_t *chain,
5370                     hammer2_blockref_t *obref)
5371 {
5372         hammer2_blockref_t *elm = &chain->bref;
5373         hammer2_blockref_t *scan;
5374         hammer2_key_t key_next;
5375         int i;
5376
5377         /*
5378          * Delete element.  Expect the element to exist.
5379          *
5380          * XXX see caller, flush code not yet sophisticated enough to prevent
5381          *     re-flushed in some cases.
5382          */
5383         key_next = 0; /* max range */
5384         i = hammer2_base_find(parent, base, count, &key_next,
5385                               elm->key, elm->key);
5386         scan = &base[i];
5387         if (i == count || scan->type == HAMMER2_BREF_TYPE_EMPTY ||
5388             scan->key != elm->key ||
5389             ((chain->flags & HAMMER2_CHAIN_BMAPUPD) == 0 &&
5390              scan->keybits != elm->keybits)) {
5391                 hammer2_spin_unex(&parent->core.spin);
5392                 panic("delete base %p element not found at %d/%d elm %p\n",
5393                       base, i, count, elm);
5394                 return;
5395         }
5396
5397         /*
5398          * Update stats and zero the entry.
5399          *
5400          * NOTE: Handle radix == 0 (0 bytes) case.
5401          */
5402         if ((int)(scan->data_off & HAMMER2_OFF_MASK_RADIX)) {
5403                 parent->bref.embed.stats.data_count -= (hammer2_off_t)1 <<
5404                                 (int)(scan->data_off & HAMMER2_OFF_MASK_RADIX);
5405         }
5406         switch(scan->type) {
5407         case HAMMER2_BREF_TYPE_INODE:
5408                 --parent->bref.embed.stats.inode_count;
5409                 /* fall through */
5410         case HAMMER2_BREF_TYPE_DATA:
5411                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5412                         atomic_set_int(&chain->flags,
5413                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5414                 } else {
5415                         if (parent->bref.leaf_count)
5416                                 --parent->bref.leaf_count;
5417                 }
5418                 /* fall through */
5419         case HAMMER2_BREF_TYPE_INDIRECT:
5420                 if (scan->type != HAMMER2_BREF_TYPE_DATA) {
5421                         parent->bref.embed.stats.data_count -=
5422                                 scan->embed.stats.data_count;
5423                         parent->bref.embed.stats.inode_count -=
5424                                 scan->embed.stats.inode_count;
5425                 }
5426                 if (scan->type == HAMMER2_BREF_TYPE_INODE)
5427                         break;
5428                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5429                         atomic_set_int(&chain->flags,
5430                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5431                 } else {
5432                         if (parent->bref.leaf_count <= scan->leaf_count)
5433                                 parent->bref.leaf_count = 0;
5434                         else
5435                                 parent->bref.leaf_count -= scan->leaf_count;
5436                 }
5437                 break;
5438         case HAMMER2_BREF_TYPE_DIRENT:
5439                 if (parent->bref.leaf_count == HAMMER2_BLOCKREF_LEAF_MAX) {
5440                         atomic_set_int(&chain->flags,
5441                                        HAMMER2_CHAIN_HINT_LEAF_COUNT);
5442                 } else {
5443                         if (parent->bref.leaf_count)
5444                                 --parent->bref.leaf_count;
5445                 }
5446         default:
5447                 break;
5448         }
5449
5450         if (obref)
5451                 *obref = *scan;
5452         bzero(scan, sizeof(*scan));
5453
5454         /*
5455          * We can only optimize parent->core.live_zero for live chains.
5456          */
5457         if (parent->core.live_zero == i + 1) {
5458                 while (--i >= 0 && base[i].type == HAMMER2_BREF_TYPE_EMPTY)
5459                         ;
5460                 parent->core.live_zero = i + 1;
5461         }
5462
5463         /*
5464          * Clear appropriate blockmap flags in chain.
5465          */
5466         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_BMAPPED |
5467                                         HAMMER2_CHAIN_BMAPUPD);
5468 }
5469
5470 /*
5471  * Insert the specified element.  The block array must not already have the
5472  * element and must have space available for the insertion.
5473  *
5474  * The spin lock on the related chain must be held.
5475  *
5476  * NOTE: live_count was adjusted when the chain was deleted, so it does not
5477  *       need to be adjusted when we commit the media change.
5478  */
5479 void
5480 hammer2_base_insert(hammer2_chain_t *parent,
5481                     hammer2_blockref_t *base, int count,
5482                     hammer2_chain_t *chain, hammer2_blockref_t *elm)
5483 {
5484         hammer2_key_t key_next;
5485         hammer2_key_t xkey;
5486         int i;
5487         int j;
5488         int k;
5489         int l;
5490         int u = 1;
5491
5492         /*
5493          * Insert new element.  Expect the element to not already exist
5494          * unless we are replacing it.
5495          *
5496          * XXX see caller, flush code not yet sophisticated enough to prevent
5497          *     re-flushed in some cases.
5498          */
5499         key_next = 0; /* max range */
5500         i = hammer2_base_find(parent, base, count, &key_next,
5501                               elm->key, elm->key);
5502
5503         /*
5504          * Shortcut fill optimization, typical ordered insertion(s) may not
5505          * require a search.
5506          */
5507         KKASSERT(i >= 0 && i <= count);
5508
5509         /*
5510          * Set appropriate blockmap flags in chain (if not NULL)
5511          */
5512         if (chain)
5513                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
5514
5515         /*
5516          * Update stats and zero the entry
5517          */
5518         if ((int)(elm->data_off & HAMMER2_OFF_MASK_RADIX)) {
5519                 parent->bref.embed.stats.data_count += (hammer2_off_t)1 <<
5520                                 (int)(elm->data_off & HAMMER2_OFF_MASK_RADIX);
5521         }
5522         switch(elm->type) {
5523         case HAMMER2_BREF_TYPE_INODE:
5524                 ++parent->bref.embed.stats.inode_count;
5525                 /* fall through */
5526         case HAMMER2_BREF_TYPE_DATA:
5527                 if (parent->bref.leaf_count != HAMMER2_BLOCKREF_LEAF_MAX)
5528                         ++parent->bref.leaf_count;
5529                 /* fall through */
5530         case HAMMER2_BREF_TYPE_INDIRECT:
5531                 if (elm->type != HAMMER2_BREF_TYPE_DATA) {
5532                         parent->bref.embed.stats.data_count +=
5533                                 elm->embed.stats.data_count;
5534                         parent->bref.embed.stats.inode_count +=
5535                                 elm->embed.stats.inode_count;
5536                 }
5537                 if (elm->type == HAMMER2_BREF_TYPE_INODE)
5538                         break;
5539                 if (parent->bref.leaf_count + elm->leaf_count <
5540                     HAMMER2_BLOCKREF_LEAF_MAX) {
5541                         parent->bref.leaf_count += elm->leaf_count;
5542                 } else {
5543                         parent->bref.leaf_count = HAMMER2_BLOCKREF_LEAF_MAX;
5544                 }
5545                 break;
5546         case HAMMER2_BREF_TYPE_DIRENT:
5547                 if (parent->bref.leaf_count != HAMMER2_BLOCKREF_LEAF_MAX)
5548                         ++parent->bref.leaf_count;
5549                 break;
5550         default:
5551                 break;
5552         }
5553
5554
5555         /*
5556          * We can only optimize parent->core.live_zero for live chains.
5557          */
5558         if (i == count && parent->core.live_zero < count) {
5559                 i = parent->core.live_zero++;
5560                 base[i] = *elm;
5561                 return;
5562         }
5563
5564         xkey = elm->key + ((hammer2_key_t)1 << elm->keybits) - 1;
5565         if (i != count && (base[i].key < elm->key || xkey >= base[i].key)) {
5566                 hammer2_spin_unex(&parent->core.spin);
5567                 panic("insert base %p overlapping elements at %d elm %p\n",
5568                       base, i, elm);
5569         }
5570
5571         /*
5572          * Try to find an empty slot before or after.
5573          */
5574         j = i;
5575         k = i;
5576         while (j > 0 || k < count) {
5577                 --j;
5578                 if (j >= 0 && base[j].type == HAMMER2_BREF_TYPE_EMPTY) {
5579                         if (j == i - 1) {
5580                                 base[j] = *elm;
5581                         } else {
5582                                 bcopy(&base[j+1], &base[j],
5583                                       (i - j - 1) * sizeof(*base));
5584                                 base[i - 1] = *elm;
5585                         }
5586                         goto validate;
5587                 }
5588                 ++k;
5589                 if (k < count && base[k].type == HAMMER2_BREF_TYPE_EMPTY) {
5590                         bcopy(&base[i], &base[i+1],
5591                               (k - i) * sizeof(hammer2_blockref_t));
5592                         base[i] = *elm;
5593
5594                         /*
5595                          * We can only update parent->core.live_zero for live
5596                          * chains.
5597                          */
5598                         if (parent->core.live_zero <= k)
5599                                 parent->core.live_zero = k + 1;
5600                         u = 2;
5601                         goto validate;
5602                 }
5603         }
5604         panic("hammer2_base_insert: no room!");
5605
5606         /*
5607          * Debugging
5608          */
5609 validate:
5610         key_next = 0;
5611         for (l = 0; l < count; ++l) {
5612                 if (base[l].type != HAMMER2_BREF_TYPE_EMPTY) {
5613                         key_next = base[l].key +
5614                                    ((hammer2_key_t)1 << base[l].keybits) - 1;
5615                         break;
5616                 }
5617         }
5618         while (++l < count) {
5619                 if (base[l].type != HAMMER2_BREF_TYPE_EMPTY) {
5620                         if (base[l].key <= key_next)
5621                                 panic("base_insert %d %d,%d,%d fail %p:%d", u, i, j, k, base, l);
5622                         key_next = base[l].key +
5623                                    ((hammer2_key_t)1 << base[l].keybits) - 1;
5624
5625                 }
5626         }
5627
5628 }
5629
5630 #if 0
5631
5632 /*
5633  * Sort the blockref array for the chain.  Used by the flush code to
5634  * sort the blockref[] array.
5635  *
5636  * The chain must be exclusively locked AND spin-locked.
5637  */
5638 typedef hammer2_blockref_t *hammer2_blockref_p;
5639
5640 static
5641 int
5642 hammer2_base_sort_callback(const void *v1, const void *v2)
5643 {
5644         hammer2_blockref_p bref1 = *(const hammer2_blockref_p *)v1;
5645         hammer2_blockref_p bref2 = *(const hammer2_blockref_p *)v2;
5646
5647         /*
5648          * Make sure empty elements are placed at the end of the array
5649          */
5650         if (bref1->type == HAMMER2_BREF_TYPE_EMPTY) {
5651                 if (bref2->type == HAMMER2_BREF_TYPE_EMPTY)
5652                         return(0);
5653                 return(1);
5654         } else if (bref2->type == HAMMER2_BREF_TYPE_EMPTY) {
5655                 return(-1);
5656         }
5657
5658         /*
5659          * Sort by key
5660          */
5661         if (bref1->key < bref2->key)
5662                 return(-1);
5663         if (bref1->key > bref2->key)
5664                 return(1);
5665         return(0);
5666 }
5667
5668 void
5669 hammer2_base_sort(hammer2_chain_t *chain)
5670 {
5671         hammer2_blockref_t *base;
5672         int count;
5673
5674         switch(chain->bref.type) {
5675         case HAMMER2_BREF_TYPE_INODE:
5676                 /*
5677                  * Special shortcut for embedded data returns the inode
5678                  * itself.  Callers must detect this condition and access
5679                  * the embedded data (the strategy code does this for us).
5680                  *
5681                  * This is only applicable to regular files and softlinks.
5682                  */
5683                 if (chain->data->ipdata.meta.op_flags &
5684                     HAMMER2_OPFLAG_DIRECTDATA) {
5685                         return;
5686                 }
5687                 base = &chain->data->ipdata.u.blockset.blockref[0];
5688                 count = HAMMER2_SET_COUNT;
5689                 break;
5690         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
5691         case HAMMER2_BREF_TYPE_INDIRECT:
5692                 /*
5693                  * Optimize indirect blocks in the INITIAL state to avoid
5694                  * I/O.
5695                  */
5696                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) == 0);
5697                 base = &chain->data->npdata[0];
5698                 count = chain->bytes / sizeof(hammer2_blockref_t);
5699                 break;
5700         case HAMMER2_BREF_TYPE_VOLUME:
5701                 base = &chain->data->voldata.sroot_blockset.blockref[0];
5702                 count = HAMMER2_SET_COUNT;
5703                 break;
5704         case HAMMER2_BREF_TYPE_FREEMAP:
5705                 base = &chain->data->blkset.blockref[0];
5706                 count = HAMMER2_SET_COUNT;
5707                 break;
5708         default:
5709                 kprintf("hammer2_chain_lookup: unrecognized "
5710                         "blockref(A) type: %d",
5711                         chain->bref.type);
5712                 while (1)
5713                         tsleep(&base, 0, "dead", 0);
5714                 panic("hammer2_base_sort: unrecognized "
5715                       "blockref(A) type: %d",
5716                       chain->bref.type);
5717                 base = NULL;    /* safety */
5718                 count = 0;      /* safety */
5719         }
5720         kqsort(base, count, sizeof(*base), hammer2_base_sort_callback);
5721 }
5722
5723 #endif
5724
5725 /*
5726  * Chain memory management
5727  */
5728 void
5729 hammer2_chain_wait(hammer2_chain_t *chain)
5730 {
5731         tsleep(chain, 0, "chnflw", 1);
5732 }
5733
5734 const hammer2_media_data_t *
5735 hammer2_chain_rdata(hammer2_chain_t *chain)
5736 {
5737         KKASSERT(chain->data != NULL);
5738         return (chain->data);
5739 }
5740
5741 hammer2_media_data_t *
5742 hammer2_chain_wdata(hammer2_chain_t *chain)
5743 {
5744         KKASSERT(chain->data != NULL);
5745         return (chain->data);
5746 }
5747
5748 /*
5749  * Set the check data for a chain.  This can be a heavy-weight operation
5750  * and typically only runs on-flush.  For file data check data is calculated
5751  * when the logical buffers are flushed.
5752  */
5753 void
5754 hammer2_chain_setcheck(hammer2_chain_t *chain, void *bdata)
5755 {
5756         chain->bref.flags &= ~HAMMER2_BREF_FLAG_ZERO;
5757
5758         switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
5759         case HAMMER2_CHECK_NONE:
5760                 break;
5761         case HAMMER2_CHECK_DISABLED:
5762                 break;
5763         case HAMMER2_CHECK_ISCSI32:
5764                 chain->bref.check.iscsi32.value =
5765                         hammer2_icrc32(bdata, chain->bytes);
5766                 break;
5767         case HAMMER2_CHECK_XXHASH64:
5768                 chain->bref.check.xxhash64.value =
5769                         XXH64(bdata, chain->bytes, XXH_HAMMER2_SEED);
5770                 break;
5771         case HAMMER2_CHECK_SHA192:
5772                 {
5773                         SHA256_CTX hash_ctx;
5774                         union {
5775                                 uint8_t digest[SHA256_DIGEST_LENGTH];
5776                                 uint64_t digest64[SHA256_DIGEST_LENGTH/8];
5777                         } u;
5778
5779                         SHA256_Init(&hash_ctx);
5780                         SHA256_Update(&hash_ctx, bdata, chain->bytes);
5781                         SHA256_Final(u.digest, &hash_ctx);
5782                         u.digest64[2] ^= u.digest64[3];
5783                         bcopy(u.digest,
5784                               chain->bref.check.sha192.data,
5785                               sizeof(chain->bref.check.sha192.data));
5786                 }
5787                 break;
5788         case HAMMER2_CHECK_FREEMAP:
5789                 chain->bref.check.freemap.icrc32 =
5790                         hammer2_icrc32(bdata, chain->bytes);
5791                 break;
5792         default:
5793                 kprintf("hammer2_chain_setcheck: unknown check type %02x\n",
5794                         chain->bref.methods);
5795                 break;
5796         }
5797 }
5798
5799 /*
5800  * Characterize a failed check code and try to trace back to the inode.
5801  */
5802 static void
5803 hammer2_characterize_failed_chain(hammer2_chain_t *chain, uint64_t check,
5804                                   int bits)
5805 {
5806         hammer2_chain_t *lchain;
5807         hammer2_chain_t *ochain;
5808
5809         kprintf("chain %016jx.%02x (%s) meth=%02x CHECK FAIL "
5810                 "(flags=%08x, bref/data ",
5811                 chain->bref.data_off,
5812                 chain->bref.type,
5813                 hammer2_bref_type_str(&chain->bref),
5814                 chain->bref.methods,
5815                 chain->flags);
5816         if (bits == 32) {
5817                 kprintf("%08x/%08x)\n",
5818                         chain->bref.check.iscsi32.value,
5819                         (uint32_t)check);
5820         } else {
5821                 kprintf("%016jx/%016jx)\n",
5822                         chain->bref.check.xxhash64.value,
5823                         check);
5824         }
5825
5826         /*
5827          * Run up the chains to try to find the governing inode so we
5828          * can report it.
5829          *
5830          * XXX This error reporting is not really MPSAFE
5831          */
5832         ochain = chain;
5833         lchain = chain;
5834         while (chain && chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
5835                 lchain = chain;
5836                 chain = chain->parent;
5837         }
5838
5839         if (chain && chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
5840             ((chain->bref.flags & HAMMER2_BREF_FLAG_PFSROOT) == 0 ||
5841              (lchain->bref.key & HAMMER2_DIRHASH_VISIBLE))) {
5842                 kprintf("   Resides at/in inode %ld\n",
5843                         chain->bref.key);
5844         } else if (chain && chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
5845                 kprintf("   Resides in inode index - CRITICAL!!!\n");
5846         } else {
5847                 kprintf("   Resides in root index - CRITICAL!!!\n");
5848         }
5849         if (ochain->hmp) {
5850                 const char *pfsname = "UNKNOWN";
5851                 int i;
5852
5853                 if (ochain->pmp) {
5854                         for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
5855                                 if (ochain->pmp->pfs_hmps[i] == ochain->hmp &&
5856                                     ochain->pmp->pfs_names[i]) {
5857                                         pfsname = ochain->pmp->pfs_names[i];
5858                                         break;
5859                                 }
5860                         }
5861                 }
5862                 kprintf("   In pfs %s on device %s\n",
5863                         pfsname, ochain->hmp->devrepname);
5864         }
5865 }
5866
5867 int
5868 hammer2_chain_testcheck(hammer2_chain_t *chain, void *bdata)
5869 {
5870         uint32_t check32;
5871         uint64_t check64;
5872         int r;
5873
5874         if (chain->bref.flags & HAMMER2_BREF_FLAG_ZERO)
5875                 return 1;
5876
5877         switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
5878         case HAMMER2_CHECK_NONE:
5879                 r = 1;
5880                 break;
5881         case HAMMER2_CHECK_DISABLED:
5882                 r = 1;
5883                 break;
5884         case HAMMER2_CHECK_ISCSI32:
5885                 check32 = hammer2_icrc32(bdata, chain->bytes);
5886                 r = (chain->bref.check.iscsi32.value == check32);
5887                 if (r == 0) {
5888                         hammer2_characterize_failed_chain(chain, check32, 32);
5889                 }
5890                 hammer2_process_icrc32 += chain->bytes;
5891                 break;
5892         case HAMMER2_CHECK_XXHASH64:
5893                 check64 = XXH64(bdata, chain->bytes, XXH_HAMMER2_SEED);
5894                 r = (chain->bref.check.xxhash64.value == check64);
5895                 if (r == 0) {
5896                         hammer2_characterize_failed_chain(chain, check64, 64);
5897                 }
5898                 hammer2_process_xxhash64 += chain->bytes;
5899                 break;
5900         case HAMMER2_CHECK_SHA192:
5901                 {
5902                         SHA256_CTX hash_ctx;
5903                         union {
5904                                 uint8_t digest[SHA256_DIGEST_LENGTH];
5905                                 uint64_t digest64[SHA256_DIGEST_LENGTH/8];
5906                         } u;
5907
5908                         SHA256_Init(&hash_ctx);
5909                         SHA256_Update(&hash_ctx, bdata, chain->bytes);
5910                         SHA256_Final(u.digest, &hash_ctx);
5911                         u.digest64[2] ^= u.digest64[3];
5912                         if (bcmp(u.digest,
5913                                  chain->bref.check.sha192.data,
5914                                  sizeof(chain->bref.check.sha192.data)) == 0) {
5915                                 r = 1;
5916                         } else {
5917                                 r = 0;
5918                                 kprintf("chain %016jx.%02x meth=%02x "
5919                                         "CHECK FAIL\n",
5920                                         chain->bref.data_off,
5921                                         chain->bref.type,
5922                                         chain->bref.methods);
5923                         }
5924                 }
5925                 break;
5926         case HAMMER2_CHECK_FREEMAP:
5927                 r = (chain->bref.check.freemap.icrc32 ==
5928                      hammer2_icrc32(bdata, chain->bytes));
5929                 if (r == 0) {
5930                         kprintf("chain %016jx.%02x meth=%02x "
5931                                 "CHECK FAIL\n",
5932                                 chain->bref.data_off,
5933                                 chain->bref.type,
5934                                 chain->bref.methods);
5935                         kprintf("freemap.icrc %08x icrc32 %08x (%d)\n",
5936                                 chain->bref.check.freemap.icrc32,
5937                                 hammer2_icrc32(bdata, chain->bytes),
5938                                                chain->bytes);
5939                         if (chain->dio)
5940                                 kprintf("dio %p buf %016jx,%d bdata %p/%p\n",
5941                                         chain->dio, chain->dio->bp->b_loffset,
5942                                         chain->dio->bp->b_bufsize, bdata,
5943                                         chain->dio->bp->b_data);
5944                 }
5945
5946                 break;
5947         default:
5948                 kprintf("hammer2_chain_setcheck: unknown check type %02x\n",
5949                         chain->bref.methods);
5950                 r = 1;
5951                 break;
5952         }
5953         return r;
5954 }
5955
5956 /*
5957  * Acquire the chain and parent representing the specified inode for the
5958  * device at the specified cluster index.
5959  *
5960  * The flags passed in are LOOKUP flags, not RESOLVE flags.
5961  *
5962  * If we are unable to locate the inode, HAMMER2_ERROR_EIO is returned and
5963  * *chainp will be NULL.  *parentp may still be set error or not, or NULL
5964  * if the parent itself could not be resolved.
5965  *
5966  * The caller may pass-in a locked *parentp and/or *chainp, or neither.
5967  * They will be unlocked and released by this function.  The *parentp and
5968  * *chainp representing the located inode are returned locked.
5969  */
5970 int
5971 hammer2_chain_inode_find(hammer2_pfs_t *pmp, hammer2_key_t inum,
5972                          int clindex, int flags,
5973                          hammer2_chain_t **parentp, hammer2_chain_t **chainp)
5974 {
5975         hammer2_chain_t *parent;
5976         hammer2_chain_t *rchain;
5977         hammer2_key_t key_dummy;
5978         hammer2_inode_t *ip;
5979         int resolve_flags;
5980         int error;
5981
5982         resolve_flags = (flags & HAMMER2_LOOKUP_SHARED) ?
5983                         HAMMER2_RESOLVE_SHARED : 0;
5984
5985         /*
5986          * Caller expects us to replace these.
5987          */
5988         if (*chainp) {
5989                 hammer2_chain_unlock(*chainp);
5990                 hammer2_chain_drop(*chainp);
5991                 *chainp = NULL;
5992         }
5993         if (*parentp) {
5994                 hammer2_chain_unlock(*parentp);
5995                 hammer2_chain_drop(*parentp);
5996                 *parentp = NULL;
5997         }
5998
5999         /*
6000          * Be very careful, this is a backend function and we CANNOT
6001          * lock any frontend inode structure we find.  But we have to
6002          * look the inode up this way first in case it exists but is
6003          * detached from the radix tree.
6004          */
6005         ip = hammer2_inode_lookup(pmp, inum);
6006         if (ip) {
6007                 *chainp = hammer2_inode_chain_and_parent(ip, clindex,
6008                                                        parentp,
6009                                                        resolve_flags);
6010                 hammer2_inode_drop(ip);
6011                 if (*chainp)
6012                         return 0;
6013                 hammer2_chain_unlock(*chainp);
6014                 hammer2_chain_drop(*chainp);
6015                 *chainp = NULL;
6016                 if (*parentp) {
6017                         hammer2_chain_unlock(*parentp);
6018                         hammer2_chain_drop(*parentp);
6019                         *parentp = NULL;
6020                 }
6021         }
6022
6023         /*
6024          * Inodes hang off of the iroot (bit 63 is clear, differentiating
6025          * inodes from root directory entries in the key lookup).
6026          */
6027         parent = hammer2_inode_chain(pmp->iroot, clindex, resolve_flags);
6028         rchain = NULL;
6029         if (parent) {
6030                 rchain = hammer2_chain_lookup(&parent, &key_dummy,
6031                                               inum, inum,
6032                                               &error, flags);
6033         } else {
6034                 error = HAMMER2_ERROR_EIO;
6035         }
6036         *parentp = parent;
6037         *chainp = rchain;
6038
6039         return error;
6040 }
6041
6042 /*
6043  * Used by the bulkscan code to snapshot the synchronized storage for
6044  * a volume, allowing it to be scanned concurrently against normal
6045  * operation.
6046  */
6047 hammer2_chain_t *
6048 hammer2_chain_bulksnap(hammer2_dev_t *hmp)
6049 {
6050         hammer2_chain_t *copy;
6051
6052         copy = hammer2_chain_alloc(hmp, hmp->spmp, &hmp->vchain.bref);
6053         copy->data = kmalloc(sizeof(copy->data->voldata),
6054                              hmp->mchain,
6055                              M_WAITOK | M_ZERO);
6056         hammer2_voldata_lock(hmp);
6057         copy->data->voldata = hmp->volsync;
6058         hammer2_voldata_unlock(hmp);
6059
6060         return copy;
6061 }
6062
6063 void
6064 hammer2_chain_bulkdrop(hammer2_chain_t *copy)
6065 {
6066         KKASSERT(copy->bref.type == HAMMER2_BREF_TYPE_VOLUME);
6067         KKASSERT(copy->data);
6068         kfree(copy->data, copy->hmp->mchain);
6069         copy->data = NULL;
6070         atomic_add_long(&hammer2_chain_allocs, -1);
6071         hammer2_chain_drop(copy);
6072 }
6073
6074 /*
6075  * Returns non-zero if the chain (INODE or DIRENT) matches the
6076  * filename.
6077  */
6078 int
6079 hammer2_chain_dirent_test(hammer2_chain_t *chain, const char *name,
6080                           size_t name_len)
6081 {
6082         const hammer2_inode_data_t *ripdata;
6083         const hammer2_dirent_head_t *den;
6084
6085         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
6086                 ripdata = &chain->data->ipdata;
6087                 if (ripdata->meta.name_len == name_len &&
6088                     bcmp(ripdata->filename, name, name_len) == 0) {
6089                         return 1;
6090                 }
6091         }
6092         if (chain->bref.type == HAMMER2_BREF_TYPE_DIRENT &&
6093            chain->bref.embed.dirent.namlen == name_len) {
6094                 den = &chain->bref.embed.dirent;
6095                 if (name_len > sizeof(chain->bref.check.buf) &&
6096                     bcmp(chain->data->buf, name, name_len) == 0) {
6097                         return 1;
6098                 }
6099                 if (name_len <= sizeof(chain->bref.check.buf) &&
6100                     bcmp(chain->bref.check.buf, name, name_len) == 0) {
6101                         return 1;
6102                 }
6103         }
6104         return 0;
6105 }