sys/vfs/hammer2/hammer2_freemap.c

   1 /*
   2  * Copyright (c) 2011-2014 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/fcntl.h>
  39 #include <sys/buf.h>
  40 #include <sys/proc.h>
  41 #include <sys/namei.h>
  42 #include <sys/mount.h>
  43 #include <sys/vnode.h>
  44 #include <sys/mountctl.h>
  45
  46 #include "hammer2.h"
  47
  48 #define FREEMAP_DEBUG   0
  49
  50 struct hammer2_fiterate {
  51         hammer2_off_t   bpref;
  52         hammer2_off_t   bnext;
  53         int             loops;
  54 };
  55
  56 typedef struct hammer2_fiterate hammer2_fiterate_t;
  57
  58 static int hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
  59                         hammer2_blockref_t *bref, int radix,
  60                         hammer2_fiterate_t *iter, hammer2_tid_t mtid);
  61 static void hammer2_freemap_init(hammer2_dev_t *hmp,
  62                         hammer2_key_t key, hammer2_chain_t *chain);
  63 static int hammer2_bmap_alloc(hammer2_dev_t *hmp,
  64                         hammer2_bmap_data_t *bmap, uint16_t class,
  65                         int n, int radix, hammer2_key_t *basep);
  66 static int hammer2_freemap_iterate(hammer2_chain_t **parentp,
  67                         hammer2_chain_t **chainp,
  68                         hammer2_fiterate_t *iter);
  69
  70 static __inline
  71 int
  72 hammer2_freemapradix(int radix)
  73 {
  74         return(radix);
  75 }
  76
  77 /*
  78  * Calculate the device offset for the specified FREEMAP_NODE or FREEMAP_LEAF
  79  * bref.  Return a combined media offset and physical size radix.  Freemap
  80  * chains use fixed storage offsets in the 4MB reserved area at the
  81  * beginning of each 2GB zone
  82  *
  83  * Rotate between four possibilities.  Theoretically this means we have three
  84  * good freemaps in case of a crash which we can use as a base for the fixup
  85  * scan at mount-time.
  86  */
  87 #define H2FMBASE(key, radix)    ((key) & ~(((hammer2_off_t)1 << (radix)) - 1))
  88 #define H2FMSHIFT(radix)        ((hammer2_off_t)1 << (radix))
  89
  90 static
  91 int
  92 hammer2_freemap_reserve(hammer2_chain_t *chain, int radix)
  93 {
  94         hammer2_blockref_t *bref = &chain->bref;
  95         hammer2_off_t off;
  96         int index;
  97         int index_inc;
  98         size_t bytes;
  99
 100         /*
 101          * Physical allocation size.
 102          */
 103         bytes = (size_t)1 << radix;
 104
 105         /*
 106          * Calculate block selection index 0..7 of current block.  If this
 107          * is the first allocation of the block (verses a modification of an
 108          * existing block), we use index 0, otherwise we use the next rotating
 109          * index.
 110          */
 111         if ((bref->data_off & ~HAMMER2_OFF_MASK_RADIX) == 0) {
 112                 index = 0;
 113         } else {
 114                 off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX &
 115                       (((hammer2_off_t)1 <<
 116                         HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
 117                 off = off / HAMMER2_PBUFSIZE;
 118                 KKASSERT(off >= HAMMER2_ZONE_FREEMAP_00 &&
 119                          off < HAMMER2_ZONE_FREEMAP_END);
 120                 index = (int)(off - HAMMER2_ZONE_FREEMAP_00) /
 121                         HAMMER2_ZONE_FREEMAP_INC;
 122                 KKASSERT(index >= 0 && index < HAMMER2_NFREEMAPS);
 123                 if (++index == HAMMER2_NFREEMAPS)
 124                         index = 0;
 125         }
 126
 127         /*
 128          * Calculate the block offset of the reserved block.  This will
 129          * point into the 4MB reserved area at the base of the appropriate
 130          * 2GB zone, once added to the FREEMAP_x selection above.
 131          */
 132         index_inc = index * HAMMER2_ZONE_FREEMAP_INC;
 133
 134         switch(bref->keybits) {
 135         /* case HAMMER2_FREEMAP_LEVEL6_RADIX: not applicable */
 136         case HAMMER2_FREEMAP_LEVEL5_RADIX:      /* 2EB */
 137                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 138                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 139                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL5_RADIX) +
 140                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 141                        HAMMER2_ZONEFM_LEVEL5) * HAMMER2_PBUFSIZE;
 142                 break;
 143         case HAMMER2_FREEMAP_LEVEL4_RADIX:      /* 2EB */
 144                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 145                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 146                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL4_RADIX) +
 147                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 148                        HAMMER2_ZONEFM_LEVEL4) * HAMMER2_PBUFSIZE;
 149                 break;
 150         case HAMMER2_FREEMAP_LEVEL3_RADIX:      /* 2PB */
 151                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 152                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 153                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL3_RADIX) +
 154                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 155                        HAMMER2_ZONEFM_LEVEL3) * HAMMER2_PBUFSIZE;
 156                 break;
 157         case HAMMER2_FREEMAP_LEVEL2_RADIX:      /* 2TB */
 158                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 159                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 160                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL2_RADIX) +
 161                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 162                        HAMMER2_ZONEFM_LEVEL2) * HAMMER2_PBUFSIZE;
 163                 break;
 164         case HAMMER2_FREEMAP_LEVEL1_RADIX:      /* 2GB */
 165                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
 166                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 167                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 168                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 169                        HAMMER2_ZONEFM_LEVEL1) * HAMMER2_PBUFSIZE;
 170                 break;
 171         default:
 172                 panic("freemap: bad radix(2) %p %d\n", bref, bref->keybits);
 173                 /* NOT REACHED */
 174                 off = (hammer2_off_t)-1;
 175                 break;
 176         }
 177         bref->data_off = off | radix;
 178 #if FREEMAP_DEBUG
 179         kprintf("FREEMAP BLOCK TYPE %d %016jx/%d DATA_OFF=%016jx\n",
 180                 bref->type, bref->key, bref->keybits, bref->data_off);
 181 #endif
 182         return (0);
 183 }
 184
 185 /*
 186  * Normal freemap allocator
 187  *
 188  * Use available hints to allocate space using the freemap.  Create missing
 189  * freemap infrastructure on-the-fly as needed (including marking initial
 190  * allocations using the iterator as allocated, instantiating new 2GB zones,
 191  * and dealing with the end-of-media edge case).
 192  *
 193  * ip and bpref are only used as a heuristic to determine locality of
 194  * reference.  bref->key may also be used heuristically.
 195  *
 196  * This function is a NOP if bytes is 0.
 197  */
 198 int
 199 hammer2_freemap_alloc(hammer2_chain_t *chain, size_t bytes)
 200 {
 201         hammer2_dev_t *hmp = chain->hmp;
 202         hammer2_blockref_t *bref = &chain->bref;
 203         hammer2_chain_t *parent;
 204         hammer2_tid_t mtid;
 205         int radix;
 206         int error;
 207         unsigned int hindex;
 208         hammer2_fiterate_t iter;
 209
 210         /*
 211          * If allocating or downsizing to zero we just get rid of whatever
 212          * data_off we had.
 213          */
 214         if (bytes == 0) {
 215                 chain->bref.data_off = 0;
 216                 return 0;
 217         }
 218
 219         mtid = hammer2_trans_sub(hmp->spmp);
 220
 221         /*
 222          * Validate the allocation size.  It must be a power of 2.
 223          *
 224          * For now require that the caller be aware of the minimum
 225          * allocation (1K).
 226          */
 227         radix = hammer2_getradix(bytes);
 228         KKASSERT((size_t)1 << radix == bytes);
 229
 230         if (bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
 231             bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
 232                 /*
 233                  * Freemap blocks themselves are assigned from the reserve
 234                  * area, not allocated from the freemap.
 235                  */
 236                 error = hammer2_freemap_reserve(chain, radix);
 237                 KKASSERT(error == 0);
 238
 239                 return error;
 240         }
 241
 242         KKASSERT(bytes >= HAMMER2_ALLOC_MIN && bytes <= HAMMER2_ALLOC_MAX);
 243
 244         /*
 245          * Calculate the starting point for our allocation search.
 246          *
 247          * Each freemap leaf is dedicated to a specific freemap_radix.
 248          * The freemap_radix can be more fine-grained than the device buffer
 249          * radix which results in inodes being grouped together in their
 250          * own segment, terminal-data (16K or less) and initial indirect
 251          * block being grouped together, and then full-indirect and full-data
 252          * blocks (64K) being grouped together.
 253          *
 254          * The single most important aspect of this is the inode grouping
 255          * because that is what allows 'find' and 'ls' and other filesystem
 256          * topology operations to run fast.
 257          */
 258 #if 0
 259         if (bref->data_off & ~HAMMER2_OFF_MASK_RADIX)
 260                 bpref = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
 261         else if (trans->tmp_bpref)
 262                 bpref = trans->tmp_bpref;
 263         else if (trans->tmp_ip)
 264                 bpref = trans->tmp_ip->chain->bref.data_off;
 265         else
 266 #endif
 267         /*
 268          * Heuristic tracking index.  We would like one for each distinct
 269          * bref type if possible.  heur_freemap[] has room for two classes
 270          * for each type.  At a minimum we have to break-up our heuristic
 271          * by device block sizes.
 272          */
 273         hindex = hammer2_devblkradix(radix) - HAMMER2_MINIORADIX;
 274         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_NRADIX);
 275         hindex += bref->type * HAMMER2_FREEMAP_HEUR_NRADIX;
 276         hindex &= HAMMER2_FREEMAP_HEUR_TYPES * HAMMER2_FREEMAP_HEUR_NRADIX - 1;
 277         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_SIZE);
 278
 279         iter.bpref = hmp->heur_freemap[hindex];
 280
 281         /*
 282          * Make sure bpref is in-bounds.  It's ok if bpref covers a zone's
 283          * reserved area, the try code will iterate past it.
 284          */
 285         if (iter.bpref > hmp->voldata.volu_size)
 286                 iter.bpref = hmp->voldata.volu_size - 1;
 287
 288         /*
 289          * Iterate the freemap looking for free space before and after.
 290          */
 291         parent = &hmp->fchain;
 292         hammer2_chain_ref(parent);
 293         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 294         error = EAGAIN;
 295         iter.bnext = iter.bpref;
 296         iter.loops = 0;
 297
 298         while (error == EAGAIN) {
 299                 error = hammer2_freemap_try_alloc(&parent, bref, radix,
 300                                                   &iter, mtid);
 301         }
 302         hmp->heur_freemap[hindex] = iter.bnext;
 303         hammer2_chain_unlock(parent);
 304         hammer2_chain_drop(parent);
 305
 306         KKASSERT(error == 0);
 307
 308         return (error);
 309 }
 310
 311 static int
 312 hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
 313                           hammer2_blockref_t *bref, int radix,
 314                           hammer2_fiterate_t *iter, hammer2_tid_t mtid)
 315 {
 316         hammer2_dev_t *hmp = (*parentp)->hmp;
 317         hammer2_off_t l0size;
 318         hammer2_off_t l1size;
 319         hammer2_off_t l1mask;
 320         hammer2_key_t key_dummy;
 321         hammer2_chain_t *chain;
 322         hammer2_off_t key;
 323         size_t bytes;
 324         uint16_t class;
 325         int error = 0;
 326         int cache_index = -1;
 327
 328         /*
 329          * Calculate the number of bytes being allocated, the number
 330          * of contiguous bits of bitmap being allocated, and the bitmap
 331          * mask.
 332          *
 333          * WARNING! cpu hardware may mask bits == 64 -> 0 and blow up the
 334          *          mask calculation.
 335          */
 336         bytes = (size_t)1 << radix;
 337         class = (bref->type << 8) | hammer2_devblkradix(radix);
 338
 339         /*
 340          * Lookup the level1 freemap chain, creating and initializing one
 341          * if necessary.  Intermediate levels will be created automatically
 342          * when necessary by hammer2_chain_create().
 343          */
 344         key = H2FMBASE(iter->bnext, HAMMER2_FREEMAP_LEVEL1_RADIX);
 345         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 346         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 347         l1mask = l1size - 1;
 348
 349         chain = hammer2_chain_lookup(parentp, &key_dummy, key, key + l1mask,
 350                                      &cache_index,
 351                                      HAMMER2_LOOKUP_ALWAYS |
 352                                      HAMMER2_LOOKUP_MATCHIND);
 353
 354         if (chain == NULL) {
 355                 /*
 356                  * Create the missing leaf, be sure to initialize
 357                  * the auxillary freemap tracking information in
 358                  * the bref.check.freemap structure.
 359                  */
 360 #if 0
 361                 kprintf("freemap create L1 @ %016jx bpref %016jx\n",
 362                         key, iter->bpref);
 363 #endif
 364                 error = hammer2_chain_create(parentp, &chain,
 365                                      hmp->spmp, HAMMER2_METH_DEFAULT,
 366                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
 367                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 368                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
 369                                      mtid, 0, 0);
 370                 KKASSERT(error == 0);
 371                 if (error == 0) {
 372                         hammer2_chain_modify(chain, mtid, 0, 0);
 373                         bzero(&chain->data->bmdata[0],
 374                               HAMMER2_FREEMAP_LEVELN_PSIZE);
 375                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
 376                         chain->bref.check.freemap.avail = l1size;
 377                         /* bref.methods should already be inherited */
 378
 379                         hammer2_freemap_init(hmp, key, chain);
 380                 }
 381         } else if (chain->error) {
 382                 /*
 383                  * Error during lookup.
 384                  */
 385                 kprintf("hammer2_freemap_try_alloc: %016jx: error %s\n",
 386                         (intmax_t)bref->data_off,
 387                         hammer2_error_str(chain->error));
 388                 error = EIO;
 389         } else if ((chain->bref.check.freemap.bigmask &
 390                    ((size_t)1 << radix)) == 0) {
 391                 /*
 392                  * Already flagged as not having enough space
 393                  */
 394                 error = ENOSPC;
 395         } else {
 396                 /*
 397                  * Modify existing chain to setup for adjustment.
 398                  */
 399                 hammer2_chain_modify(chain, mtid, 0, 0);
 400         }
 401
 402         /*
 403          * Scan 2MB entries.
 404          */
 405         if (error == 0) {
 406                 hammer2_bmap_data_t *bmap;
 407                 hammer2_key_t base_key;
 408                 int count;
 409                 int start;
 410                 int n;
 411
 412                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
 413                 start = (int)((iter->bnext - key) >>
 414                               HAMMER2_FREEMAP_LEVEL0_RADIX);
 415                 KKASSERT(start >= 0 && start < HAMMER2_FREEMAP_COUNT);
 416                 hammer2_chain_modify(chain, mtid, 0, 0);
 417
 418                 error = ENOSPC;
 419                 for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 420                         int availchk;
 421
 422                         if (start + count >= HAMMER2_FREEMAP_COUNT &&
 423                             start - count < 0) {
 424                                 break;
 425                         }
 426
 427                         /*
 428                          * Calculate bmap pointer
 429                          *
 430                          * NOTE: bmap pointer is invalid if n >= FREEMAP_COUNT.
 431                          */
 432                         n = start + count;
 433                         bmap = &chain->data->bmdata[n];
 434
 435                         if (n >= HAMMER2_FREEMAP_COUNT) {
 436                                 availchk = 0;
 437                         } else if (bmap->avail) {
 438                                 availchk = 1;
 439                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
 440                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
 441                                 availchk = 1;
 442                         } else {
 443                                 availchk = 0;
 444                         }
 445
 446                         if (availchk &&
 447                             (bmap->class == 0 || bmap->class == class)) {
 448                                 base_key = key + n * l0size;
 449                                 error = hammer2_bmap_alloc(hmp, bmap,
 450                                                            class, n, radix,
 451                                                            &base_key);
 452                                 if (error != ENOSPC) {
 453                                         key = base_key;
 454                                         break;
 455                                 }
 456                         }
 457
 458                         /*
 459                          * Must recalculate after potentially having called
 460                          * hammer2_bmap_alloc() above in case chain was
 461                          * reallocated.
 462                          *
 463                          * NOTE: bmap pointer is invalid if n < 0.
 464                          */
 465                         n = start - count;
 466                         bmap = &chain->data->bmdata[n];
 467                         if (n < 0) {
 468                                 availchk = 0;
 469                         } else if (bmap->avail) {
 470                                 availchk = 1;
 471                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
 472                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
 473                                 availchk = 1;
 474                         } else {
 475                                 availchk = 0;
 476                         }
 477
 478                         if (availchk &&
 479                             (bmap->class == 0 || bmap->class == class)) {
 480                                 base_key = key + n * l0size;
 481                                 error = hammer2_bmap_alloc(hmp, bmap,
 482                                                            class, n, radix,
 483                                                            &base_key);
 484                                 if (error != ENOSPC) {
 485                                         key = base_key;
 486                                         break;
 487                                 }
 488                         }
 489                 }
 490                 if (error == ENOSPC) {
 491                         chain->bref.check.freemap.bigmask &=
 492                                 (uint32_t)~((size_t)1 << radix);
 493                 }
 494                 /* XXX also scan down from original count */
 495         }
 496
 497         if (error == 0) {
 498                 /*
 499                  * Assert validity.  Must be beyond the static allocator used
 500                  * by newfs_hammer2 (and thus also beyond the aux area),
 501                  * not go past the volume size, and must not be in the
 502                  * reserved segment area for a zone.
 503                  */
 504                 KKASSERT(key >= hmp->voldata.allocator_beg &&
 505                          key + bytes <= hmp->voldata.volu_size);
 506                 KKASSERT((key & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
 507                 bref->data_off = key | radix;
 508 #if 0
 509                 kprintf("alloc cp=%p %016jx %016jx using %016jx\n",
 510                         chain,
 511                         bref->key, bref->data_off, chain->bref.data_off);
 512 #endif
 513         } else if (error == ENOSPC) {
 514                 /*
 515                  * Return EAGAIN with next iteration in iter->bnext, or
 516                  * return ENOSPC if the allocation map has been exhausted.
 517                  */
 518                 error = hammer2_freemap_iterate(parentp, &chain, iter);
 519         }
 520
 521         /*
 522          * Cleanup
 523          */
 524         if (chain) {
 525                 hammer2_chain_unlock(chain);
 526                 hammer2_chain_drop(chain);
 527         }
 528         return (error);
 529 }
 530
 531 /*
 532  * Allocate (1<<radix) bytes from the bmap whos base data offset is (*basep).
 533  *
 534  * If the linear iterator is mid-block we use it directly (the bitmap should
 535  * already be marked allocated), otherwise we search for a block in the bitmap
 536  * that fits the allocation request.
 537  *
 538  * A partial bitmap allocation sets the minimum bitmap granularity (16KB)
 539  * to fully allocated and adjusts the linear allocator to allow the
 540  * remaining space to be allocated.
 541  */
 542 static
 543 int
 544 hammer2_bmap_alloc(hammer2_dev_t *hmp, hammer2_bmap_data_t *bmap,
 545                    uint16_t class, int n, int radix, hammer2_key_t *basep)
 546 {
 547         size_t size;
 548         size_t bgsize;
 549         int bmradix;
 550         hammer2_bitmap_t bmmask;
 551         int offset;
 552         int i;
 553         int j;
 554
 555         /*
 556          * Take into account 2-bits per block when calculating bmradix.
 557          */
 558         size = (size_t)1 << radix;
 559
 560         if (radix <= HAMMER2_FREEMAP_BLOCK_RADIX) {
 561                 bmradix = 2;
 562                 /* (16K) 2 bits per allocation block */
 563         } else {
 564                 bmradix = (hammer2_bitmap_t)2 <<
 565                           (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
 566                 /* (32K-256K) 4, 8, 16, 32 bits per allocation block */
 567         }
 568
 569         /*
 570          * Use the linear iterator to pack small allocations, otherwise
 571          * fall-back to finding a free 16KB chunk.  The linear iterator
 572          * is only valid when *NOT* on a freemap chunking boundary (16KB).
 573          * If it is the bitmap must be scanned.  It can become invalid
 574          * once we pack to the boundary.  We adjust it after a bitmap
 575          * allocation only for sub-16KB allocations (so the perfectly good
 576          * previous value can still be used for fragments when 16KB+
 577          * allocations are made).
 578          *
 579          * Beware of hardware artifacts when bmradix == 64 (intermediate
 580          * result can wind up being '1' instead of '0' if hardware masks
 581          * bit-count & 31).
 582          *
 583          * NOTE: j needs to be even in the j= calculation.  As an artifact
 584          *       of the /2 division, our bitmask has to clear bit 0.
 585          *
 586          * NOTE: TODO this can leave little unallocatable fragments lying
 587          *       around.
 588          */
 589         if (((uint32_t)bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) + size <=
 590             HAMMER2_FREEMAP_BLOCK_SIZE &&
 591             (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) &&
 592             bmap->linear < HAMMER2_SEGSIZE) {
 593                 KKASSERT(bmap->linear >= 0 &&
 594                          bmap->linear + size <= HAMMER2_SEGSIZE &&
 595                          (bmap->linear & (HAMMER2_ALLOC_MIN - 1)) == 0);
 596                 offset = bmap->linear;
 597                 i = offset / (HAMMER2_SEGSIZE / 8);
 598                 j = (offset / (HAMMER2_FREEMAP_BLOCK_SIZE / 2)) & 30;
 599                 bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 600                          HAMMER2_BMAP_ALLONES :
 601                          ((hammer2_bitmap_t)1 << bmradix) - 1;
 602                 bmmask <<= j;
 603                 bmap->linear = offset + size;
 604         } else {
 605                 for (i = 0; i < HAMMER2_BMAP_ELEMENTS; ++i) {
 606                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 607                                  HAMMER2_BMAP_ALLONES :
 608                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
 609                         for (j = 0;
 610                              j < HAMMER2_BMAP_BITS_PER_ELEMENT;
 611                              j += bmradix) {
 612                                 if ((bmap->bitmapq[i] & bmmask) == 0)
 613                                         goto success;
 614                                 bmmask <<= bmradix;
 615                         }
 616                 }
 617                 /*fragments might remain*/
 618                 /*KKASSERT(bmap->avail == 0);*/
 619                 return (ENOSPC);
 620 success:
 621                 offset = i * (HAMMER2_SEGSIZE / HAMMER2_BMAP_ELEMENTS) +
 622                          (j * (HAMMER2_FREEMAP_BLOCK_SIZE / 2));
 623                 if (size & HAMMER2_FREEMAP_BLOCK_MASK)
 624                         bmap->linear = offset + size;
 625         }
 626
 627         /* 8 x (64/2) -> 256 x 16K -> 4MB */
 628         KKASSERT(i >= 0 && i < HAMMER2_BMAP_ELEMENTS);
 629
 630         /*
 631          * Optimize the buffer cache to avoid unnecessary read-before-write
 632          * operations.
 633          *
 634          * The device block size could be larger than the allocation size
 635          * so the actual bitmap test is somewhat more involved.  We have
 636          * to use a compatible buffer size for this operation.
 637          */
 638         if ((bmap->bitmapq[i] & bmmask) == 0 &&
 639             hammer2_devblksize(size) != size) {
 640                 size_t psize = hammer2_devblksize(size);
 641                 hammer2_off_t pmask = (hammer2_off_t)psize - 1;
 642                 int pbmradix = (hammer2_bitmap_t)2 <<
 643                                         (hammer2_devblkradix(radix) -
 644                                HAMMER2_FREEMAP_BLOCK_RADIX);
 645                 hammer2_bitmap_t pbmmask;
 646                 int pradix = hammer2_getradix(psize);
 647
 648                 pbmmask = (pbmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 649                         HAMMER2_BMAP_ALLONES :
 650                         ((hammer2_bitmap_t)1 << pbmradix) - 1;
 651                 while ((pbmmask & bmmask) == 0)
 652                         pbmmask <<= pbmradix;
 653
 654 #if 0
 655                 kprintf("%016jx mask %016jx %016jx %016jx (%zd/%zd)\n",
 656                         *basep + offset, bmap->bitmapq[i],
 657                         pbmmask, bmmask, size, psize);
 658 #endif
 659
 660                 if ((bmap->bitmapq[i] & pbmmask) == 0) {
 661                         hammer2_io_newq(hmp, HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 662                                         (*basep + (offset & ~pmask)) |
 663                                         pradix, psize);
 664                 }
 665         }
 666
 667 #if 0
 668         /*
 669          * When initializing a new inode segment also attempt to initialize
 670          * an adjacent segment.  Be careful not to index beyond the array
 671          * bounds.
 672          *
 673          * We do this to try to localize inode accesses to improve
 674          * directory scan rates.  XXX doesn't improve scan rates.
 675          */
 676         if (size == HAMMER2_INODE_BYTES) {
 677                 if (n & 1) {
 678                         if (bmap[-1].radix == 0 && bmap[-1].avail)
 679                                 bmap[-1].radix = radix;
 680                 } else {
 681                         if (bmap[1].radix == 0 && bmap[1].avail)
 682                                 bmap[1].radix = radix;
 683                 }
 684         }
 685 #endif
 686         /*
 687          * Calculate the bitmap-granular change in bgsize for the volume
 688          * header.  We cannot use the fine-grained change here because
 689          * the bulkfree code can't undo it.  If the bitmap element is already
 690          * marked allocated it has already been accounted for.
 691          */
 692         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
 693                 if (bmap->bitmapq[i] & bmmask)
 694                         bgsize = 0;
 695                 else
 696                         bgsize = HAMMER2_FREEMAP_BLOCK_SIZE;
 697         } else {
 698                 bgsize = size;
 699         }
 700
 701         /*
 702          * Adjust the bitmap, set the class (it might have been 0),
 703          * and available bytes, update the allocation offset (*basep)
 704          * from the L0 base to the actual offset.
 705          *
 706          * avail must reflect the bitmap-granular availability.  The allocator
 707          * tests will also check the linear iterator.
 708          */
 709         bmap->bitmapq[i] |= bmmask;
 710         bmap->class = class;
 711         bmap->avail -= bgsize;
 712         *basep += offset;
 713
 714         /*
 715          * Adjust the volume header's allocator_free parameter.  This
 716          * parameter has to be fixed up by bulkfree which has no way to
 717          * figure out sub-16K chunking, so it must be adjusted by the
 718          * bitmap-granular size.
 719          */
 720         if (bgsize) {
 721                 hammer2_voldata_lock(hmp);
 722                 hammer2_voldata_modify(hmp);
 723                 hmp->voldata.allocator_free -= bgsize;
 724                 hammer2_voldata_unlock(hmp);
 725         }
 726
 727         return(0);
 728 }
 729
 730 static
 731 void
 732 hammer2_freemap_init(hammer2_dev_t *hmp, hammer2_key_t key,
 733                      hammer2_chain_t *chain)
 734 {
 735         hammer2_off_t l1size;
 736         hammer2_off_t lokey;
 737         hammer2_off_t hikey;
 738         hammer2_bmap_data_t *bmap;
 739         int count;
 740
 741         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 742
 743         /*
 744          * Calculate the portion of the 2GB map that should be initialized
 745          * as free.  Portions below or after will be initialized as allocated.
 746          * SEGMASK-align the areas so we don't have to worry about sub-scans
 747          * or endianess when using memset.
 748          *
 749          * (1) Ensure that all statically allocated space from newfs_hammer2
 750          *     is marked allocated.
 751          *
 752          * (2) Ensure that the reserved area is marked allocated (typically
 753          *     the first 4MB of the 2GB area being represented).
 754          *
 755          * (3) Ensure that any trailing space at the end-of-volume is marked
 756          *     allocated.
 757          *
 758          * WARNING! It is possible for lokey to be larger than hikey if the
 759          *          entire 2GB segment is within the static allocation.
 760          */
 761         lokey = (hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
 762                 ~HAMMER2_SEGMASK64;
 763
 764         if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 765                   HAMMER2_ZONE_SEG64) {
 766                 lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 767                         HAMMER2_ZONE_SEG64;
 768         }
 769
 770         hikey = key + H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 771         if (hikey > hmp->voldata.volu_size) {
 772                 hikey = hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
 773         }
 774
 775         chain->bref.check.freemap.avail =
 776                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 777         bmap = &chain->data->bmdata[0];
 778
 779         for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 780                 if (key < lokey || key >= hikey) {
 781                         memset(bmap->bitmapq, -1,
 782                                sizeof(bmap->bitmapq));
 783                         bmap->avail = 0;
 784                         bmap->linear = HAMMER2_SEGSIZE;
 785                         chain->bref.check.freemap.avail -=
 786                                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 787                 } else {
 788                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 789                 }
 790                 key += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 791                 ++bmap;
 792         }
 793 }
 794
 795 /*
 796  * The current Level 1 freemap has been exhausted, iterate to the next
 797  * one, return ENOSPC if no freemaps remain.
 798  *
 799  * XXX this should rotate back to the beginning to handle freed-up space
 800  * XXX or use intermediate entries to locate free space. TODO
 801  */
 802 static int
 803 hammer2_freemap_iterate(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
 804                         hammer2_fiterate_t *iter)
 805 {
 806         hammer2_dev_t *hmp = (*parentp)->hmp;
 807
 808         iter->bnext &= ~(H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
 809         iter->bnext += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 810         if (iter->bnext >= hmp->voldata.volu_size) {
 811                 iter->bnext = 0;
 812                 if (++iter->loops == 2)
 813                         return (ENOSPC);
 814         }
 815         return(EAGAIN);
 816 }
 817
 818 /*
 819  * Adjust the bit-pattern for data in the freemap bitmap according to
 820  * (how).  This code is called from on-mount recovery to fixup (mark
 821  * as allocated) blocks whos freemap upates might not have been committed
 822  * in the last crash and is used by the bulk freemap scan to stage frees.
 823  *
 824  * WARNING! Cannot be called with a empty-data bref (radix == 0).
 825  *
 826  * XXX currently disabled when how == 0 (the normal real-time case).  At
 827  * the moment we depend on the bulk freescan to actually free blocks.  It
 828  * will still call this routine with a non-zero how to stage possible frees
 829  * and to do the actual free.
 830  */
 831 void
 832 hammer2_freemap_adjust(hammer2_dev_t *hmp, hammer2_blockref_t *bref,
 833                        int how)
 834 {
 835         hammer2_off_t data_off = bref->data_off;
 836         hammer2_chain_t *chain;
 837         hammer2_chain_t *parent;
 838         hammer2_bmap_data_t *bmap;
 839         hammer2_key_t key;
 840         hammer2_key_t key_dummy;
 841         hammer2_off_t l0size;
 842         hammer2_off_t l1size;
 843         hammer2_off_t l1mask;
 844         hammer2_tid_t mtid;
 845         hammer2_bitmap_t *bitmap;
 846         const hammer2_bitmap_t bmmask00 = 0;
 847         hammer2_bitmap_t bmmask01;
 848         hammer2_bitmap_t bmmask10;
 849         hammer2_bitmap_t bmmask11;
 850         size_t bytes;
 851         uint16_t class;
 852         int radix;
 853         int start;
 854         int count;
 855         int modified = 0;
 856         int cache_index = -1;
 857         int error;
 858         size_t bgsize = 0;
 859
 860         KKASSERT(how == HAMMER2_FREEMAP_DORECOVER);
 861
 862         mtid = hammer2_trans_sub(hmp->spmp);
 863
 864         radix = (int)data_off & HAMMER2_OFF_MASK_RADIX;
 865         KKASSERT(radix != 0);
 866         data_off &= ~HAMMER2_OFF_MASK_RADIX;
 867         KKASSERT(radix <= HAMMER2_RADIX_MAX);
 868
 869         if (radix)
 870                 bytes = (size_t)1 << radix;
 871         else
 872                 bytes = 0;
 873         class = (bref->type << 8) | hammer2_devblkradix(radix);
 874
 875         /*
 876          * We can't adjust the freemap for data allocations made by
 877          * newfs_hammer2.
 878          */
 879         if (data_off < hmp->voldata.allocator_beg)
 880                 return;
 881
 882         KKASSERT((data_off & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
 883
 884         /*
 885          * Lookup the level1 freemap chain.  The chain must exist.
 886          */
 887         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL1_RADIX);
 888         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 889         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 890         l1mask = l1size - 1;
 891
 892         parent = &hmp->fchain;
 893         hammer2_chain_ref(parent);
 894         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 895
 896         chain = hammer2_chain_lookup(&parent, &key_dummy, key, key + l1mask,
 897                                      &cache_index,
 898                                      HAMMER2_LOOKUP_ALWAYS |
 899                                      HAMMER2_LOOKUP_MATCHIND);
 900
 901         /*
 902          * Stop early if we are trying to free something but no leaf exists.
 903          */
 904         if (chain == NULL && how != HAMMER2_FREEMAP_DORECOVER) {
 905                 kprintf("hammer2_freemap_adjust: %016jx: no chain\n",
 906                         (intmax_t)bref->data_off);
 907                 goto done;
 908         }
 909         if (chain->error) {
 910                 kprintf("hammer2_freemap_adjust: %016jx: error %s\n",
 911                         (intmax_t)bref->data_off,
 912                         hammer2_error_str(chain->error));
 913                 hammer2_chain_unlock(chain);
 914                 hammer2_chain_drop(chain);
 915                 chain = NULL;
 916                 goto done;
 917         }
 918
 919         /*
 920          * Create any missing leaf(s) if we are doing a recovery (marking
 921          * the block(s) as being allocated instead of being freed).  Be sure
 922          * to initialize the auxillary freemap tracking info in the
 923          * bref.check.freemap structure.
 924          */
 925         if (chain == NULL && how == HAMMER2_FREEMAP_DORECOVER) {
 926                 error = hammer2_chain_create(&parent, &chain,
 927                                      hmp->spmp, HAMMER2_METH_DEFAULT,
 928                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
 929                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 930                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
 931                                      mtid, 0, 0);
 932
 933                 if (hammer2_debug & 0x0040) {
 934                         kprintf("fixup create chain %p %016jx:%d\n",
 935                                 chain, chain->bref.key, chain->bref.keybits);
 936                 }
 937
 938                 if (error == 0) {
 939                         hammer2_chain_modify(chain, mtid, 0, 0);
 940                         bzero(&chain->data->bmdata[0],
 941                               HAMMER2_FREEMAP_LEVELN_PSIZE);
 942                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
 943                         chain->bref.check.freemap.avail = l1size;
 944                         /* bref.methods should already be inherited */
 945
 946                         hammer2_freemap_init(hmp, key, chain);
 947                 }
 948                 /* XXX handle error */
 949         }
 950
 951 #if FREEMAP_DEBUG
 952         kprintf("FREEMAP ADJUST TYPE %d %016jx/%d DATA_OFF=%016jx\n",
 953                 chain->bref.type, chain->bref.key,
 954                 chain->bref.keybits, chain->bref.data_off);
 955 #endif
 956
 957         /*
 958          * Calculate the bitmask (runs in 2-bit pairs).
 959          */
 960         start = ((int)(data_off >> HAMMER2_FREEMAP_BLOCK_RADIX) & 15) * 2;
 961         bmmask01 = (hammer2_bitmap_t)1 << start;
 962         bmmask10 = (hammer2_bitmap_t)2 << start;
 963         bmmask11 = (hammer2_bitmap_t)3 << start;
 964
 965         /*
 966          * Fixup the bitmap.  Partial blocks cannot be fully freed unless
 967          * a bulk scan is able to roll them up.
 968          */
 969         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
 970                 count = 1;
 971                 if (how == HAMMER2_FREEMAP_DOREALFREE)
 972                         how = HAMMER2_FREEMAP_DOMAYFREE;
 973         } else {
 974                 count = 1 << (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
 975         }
 976
 977         /*
 978          * [re]load the bmap and bitmap pointers.  Each bmap entry covers
 979          * a 2MB swath.  The bmap itself (LEVEL1) covers 2GB.
 980          *
 981          * Be sure to reset the linear iterator to ensure that the adjustment
 982          * is not ignored.
 983          */
 984 again:
 985         bmap = &chain->data->bmdata[(int)(data_off >> HAMMER2_SEGRADIX) &
 986                                     (HAMMER2_FREEMAP_COUNT - 1)];
 987         bitmap = &bmap->bitmapq[(int)(data_off >> (HAMMER2_SEGRADIX - 3)) & 7];
 988
 989         if (modified)
 990                 bmap->linear = 0;
 991
 992         while (count) {
 993                 KKASSERT(bmmask11);
 994                 if (how == HAMMER2_FREEMAP_DORECOVER) {
 995                         /*
 996                          * Recovery request, mark as allocated.
 997                          */
 998                         if ((*bitmap & bmmask11) != bmmask11) {
 999                                 if (modified == 0) {
1000                                         hammer2_chain_modify(chain, mtid, 0, 0);
1001                                         modified = 1;
1002                                         goto again;
1003                                 }
1004                                 if ((*bitmap & bmmask11) == bmmask00) {
1005                                         bmap->avail -=
1006                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1007                                         bgsize += HAMMER2_FREEMAP_BLOCK_SIZE;
1008                                 }
1009                                 if (bmap->class == 0)
1010                                         bmap->class = class;
1011                                 *bitmap |= bmmask11;
1012                                 if (hammer2_debug & 0x0040) {
1013                                         kprintf("hammer2_freemap_recover: "
1014                                                 "fixup type=%02x "
1015                                                 "block=%016jx/%zd\n",
1016                                                 bref->type, data_off, bytes);
1017                                 }
1018                         } else {
1019                                 /*
1020                                 kprintf("hammer2_freemap_recover:  good "
1021                                         "type=%02x block=%016jx/%zd\n",
1022                                         bref->type, data_off, bytes);
1023                                 */
1024                         }
1025                 }
1026 #if 0
1027                 /*
1028                  * XXX this stuff doesn't work, avail is miscalculated and
1029                  * code 10 means something else now.
1030                  */
1031                 else if ((*bitmap & bmmask11) == bmmask11) {
1032                         /*
1033                          * Mayfree/Realfree request and bitmap is currently
1034                          * marked as being fully allocated.
1035                          */
1036                         if (!modified) {
1037                                 hammer2_chain_modify(chain, 0);
1038                                 modified = 1;
1039                                 goto again;
1040                         }
1041                         if (how == HAMMER2_FREEMAP_DOREALFREE)
1042                                 *bitmap &= ~bmmask11;
1043                         else
1044                                 *bitmap = (*bitmap & ~bmmask11) | bmmask10;
1045                 } else if ((*bitmap & bmmask11) == bmmask10) {
1046                         /*
1047                          * Mayfree/Realfree request and bitmap is currently
1048                          * marked as being possibly freeable.
1049                          */
1050                         if (how == HAMMER2_FREEMAP_DOREALFREE) {
1051                                 if (!modified) {
1052                                         hammer2_chain_modify(chain, 0);
1053                                         modified = 1;
1054                                         goto again;
1055                                 }
1056                                 *bitmap &= ~bmmask11;
1057                         }
1058                 } else {
1059                         /*
1060                          * 01 - Not implemented, currently illegal state
1061                          * 00 - Not allocated at all, illegal free.
1062                          */
1063                         panic("hammer2_freemap_adjust: "
1064                               "Illegal state %08x(%08x)",
1065                               *bitmap, *bitmap & bmmask11);
1066                 }
1067 #endif
1068                 --count;
1069                 bmmask01 <<= 2;
1070                 bmmask10 <<= 2;
1071                 bmmask11 <<= 2;
1072         }
1073 #if HAMMER2_BMAP_ELEMENTS != 8
1074 #error "hammer2_freemap.c: HAMMER2_BMAP_ELEMENTS expected to be 8"
1075 #endif
1076         if (how == HAMMER2_FREEMAP_DOREALFREE && modified) {
1077                 bmap->avail += 1 << radix;
1078                 KKASSERT(bmap->avail <= HAMMER2_SEGSIZE);
1079                 if (bmap->avail == HAMMER2_SEGSIZE &&
1080                     bmap->bitmapq[0] == 0 &&
1081                     bmap->bitmapq[1] == 0 &&
1082                     bmap->bitmapq[2] == 0 &&
1083                     bmap->bitmapq[3] == 0 &&
1084                     bmap->bitmapq[4] == 0 &&
1085                     bmap->bitmapq[5] == 0 &&
1086                     bmap->bitmapq[6] == 0 &&
1087                     bmap->bitmapq[7] == 0) {
1088                         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL0_RADIX);
1089                         kprintf("Freeseg %016jx\n", (intmax_t)key);
1090                         bmap->class = 0;
1091                 }
1092         }
1093
1094         /*
1095          * chain->bref.check.freemap.bigmask (XXX)
1096          *
1097          * Setting bigmask is a hint to the allocation code that there might
1098          * be something allocatable.  We also set this in recovery... it
1099          * doesn't hurt and we might want to use the hint for other validation
1100          * operations later on.
1101          */
1102         if (modified)
1103                 chain->bref.check.freemap.bigmask |= 1 << radix;
1104
1105         hammer2_chain_unlock(chain);
1106         hammer2_chain_drop(chain);
1107 done:
1108         hammer2_chain_unlock(parent);
1109         hammer2_chain_drop(parent);
1110
1111         if (bgsize) {
1112                 hammer2_voldata_lock(hmp);
1113                 hammer2_voldata_modify(hmp);
1114                 hmp->voldata.allocator_free -= bgsize;
1115                 hammer2_voldata_unlock(hmp);
1116         }
1117 }
1118
1119 /*
1120  * Validate the freemap, in three stages.
1121  *
1122  * stage-1      ALLOCATED     -> POSSIBLY FREE
1123  *              POSSIBLY FREE -> POSSIBLY FREE (type corrected)
1124  *
1125  *      This transitions bitmap entries from ALLOCATED to POSSIBLY FREE.
1126  *      The POSSIBLY FREE state does not mean that a block is actually free
1127  *      and may be transitioned back to ALLOCATED in stage-2.
1128  *
1129  *      This is typically done during normal filesystem operations when
1130  *      something is deleted or a block is replaced.
1131  *
1132  *      This is done by bulkfree in-bulk after a memory-bounded meta-data
1133  *      scan to try to determine what might be freeable.
1134  *
1135  *      This can be done unconditionally through a freemap scan when the
1136  *      intention is to brute-force recover the proper state of the freemap.
1137  *
1138  * stage-2      POSSIBLY FREE -> ALLOCATED      (scan metadata topology)
1139  *
1140  *      This is done by bulkfree during a meta-data scan to ensure that
1141  *      all blocks still actually allocated by the filesystem are marked
1142  *      as such.
1143  *
1144  *      NOTE! Live filesystem transitions to POSSIBLY FREE can occur while
1145  *            the bulkfree stage-2 and stage-3 is running.  The live filesystem
1146  *            will use the alternative POSSIBLY FREE type (2) to prevent
1147  *            stage-3 from improperly transitioning unvetted possibly-free
1148  *            blocks to FREE.
1149  *
1150  * stage-3      POSSIBLY FREE (type 1) -> FREE  (scan freemap)
1151  *
1152  *      This is done by bulkfree to finalize POSSIBLY FREE states.
1153  *
1154  */