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
 509                 /*
 510                  * Record dedupability.  The dedup bits are cleared
 511                  * when bulkfree transitions the freemap from 11->10,
 512                  * and asserted to be clear on the 10->00 transition.
 513                  *
 514                  * We must record the bitmask with the chain locked
 515                  * at the time we set the allocation bits to avoid
 516                  * racing a bulkfree.
 517                  */
 518                 if (bref->type == HAMMER2_BREF_TYPE_DATA)
 519                         hammer2_io_dedup_set(hmp, bref);
 520 #if 0
 521                 kprintf("alloc cp=%p %016jx %016jx using %016jx\n",
 522                         chain,
 523                         bref->key, bref->data_off, chain->bref.data_off);
 524 #endif
 525         } else if (error == ENOSPC) {
 526                 /*
 527                  * Return EAGAIN with next iteration in iter->bnext, or
 528                  * return ENOSPC if the allocation map has been exhausted.
 529                  */
 530                 error = hammer2_freemap_iterate(parentp, &chain, iter);
 531         }
 532
 533         /*
 534          * Cleanup
 535          */
 536         if (chain) {
 537                 hammer2_chain_unlock(chain);
 538                 hammer2_chain_drop(chain);
 539         }
 540         return (error);
 541 }
 542
 543 /*
 544  * Allocate (1<<radix) bytes from the bmap whos base data offset is (*basep).
 545  *
 546  * If the linear iterator is mid-block we use it directly (the bitmap should
 547  * already be marked allocated), otherwise we search for a block in the bitmap
 548  * that fits the allocation request.
 549  *
 550  * A partial bitmap allocation sets the minimum bitmap granularity (16KB)
 551  * to fully allocated and adjusts the linear allocator to allow the
 552  * remaining space to be allocated.
 553  */
 554 static
 555 int
 556 hammer2_bmap_alloc(hammer2_dev_t *hmp, hammer2_bmap_data_t *bmap,
 557                    uint16_t class, int n, int radix, hammer2_key_t *basep)
 558 {
 559         size_t size;
 560         size_t bgsize;
 561         int bmradix;
 562         hammer2_bitmap_t bmmask;
 563         int offset;
 564         int i;
 565         int j;
 566
 567         /*
 568          * Take into account 2-bits per block when calculating bmradix.
 569          */
 570         size = (size_t)1 << radix;
 571
 572         if (radix <= HAMMER2_FREEMAP_BLOCK_RADIX) {
 573                 bmradix = 2;
 574                 /* (16K) 2 bits per allocation block */
 575         } else {
 576                 bmradix = (hammer2_bitmap_t)2 <<
 577                           (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
 578                 /* (32K-256K) 4, 8, 16, 32 bits per allocation block */
 579         }
 580
 581         /*
 582          * Use the linear iterator to pack small allocations, otherwise
 583          * fall-back to finding a free 16KB chunk.  The linear iterator
 584          * is only valid when *NOT* on a freemap chunking boundary (16KB).
 585          * If it is the bitmap must be scanned.  It can become invalid
 586          * once we pack to the boundary.  We adjust it after a bitmap
 587          * allocation only for sub-16KB allocations (so the perfectly good
 588          * previous value can still be used for fragments when 16KB+
 589          * allocations are made inbetween fragmentary allocations).
 590          *
 591          * Beware of hardware artifacts when bmradix == 64 (intermediate
 592          * result can wind up being '1' instead of '0' if hardware masks
 593          * bit-count & 63).
 594          *
 595          * NOTE: j needs to be even in the j= calculation.  As an artifact
 596          *       of the /2 division, our bitmask has to clear bit 0.
 597          *
 598          * NOTE: TODO this can leave little unallocatable fragments lying
 599          *       around.
 600          */
 601         if (((uint32_t)bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) + size <=
 602             HAMMER2_FREEMAP_BLOCK_SIZE &&
 603             (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) &&
 604             bmap->linear < HAMMER2_SEGSIZE) {
 605                 KKASSERT(bmap->linear >= 0 &&
 606                          bmap->linear + size <= HAMMER2_SEGSIZE &&
 607                          (bmap->linear & (HAMMER2_ALLOC_MIN - 1)) == 0);
 608                 offset = bmap->linear;
 609                 i = offset / (HAMMER2_SEGSIZE / 8);
 610                 j = (offset / (HAMMER2_FREEMAP_BLOCK_SIZE / 2)) & 30;
 611                 bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 612                          HAMMER2_BMAP_ALLONES :
 613                          ((hammer2_bitmap_t)1 << bmradix) - 1;
 614                 bmmask <<= j;
 615                 bmap->linear = offset + size;
 616         } else {
 617                 for (i = 0; i < HAMMER2_BMAP_ELEMENTS; ++i) {
 618                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 619                                  HAMMER2_BMAP_ALLONES :
 620                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
 621                         for (j = 0;
 622                              j < HAMMER2_BMAP_BITS_PER_ELEMENT;
 623                              j += bmradix) {
 624                                 if ((bmap->bitmapq[i] & bmmask) == 0)
 625                                         goto success;
 626                                 bmmask <<= bmradix;
 627                         }
 628                 }
 629                 /*fragments might remain*/
 630                 /*KKASSERT(bmap->avail == 0);*/
 631                 return (ENOSPC);
 632 success:
 633                 offset = i * (HAMMER2_SEGSIZE / HAMMER2_BMAP_ELEMENTS) +
 634                          (j * (HAMMER2_FREEMAP_BLOCK_SIZE / 2));
 635                 if (size & HAMMER2_FREEMAP_BLOCK_MASK)
 636                         bmap->linear = offset + size;
 637         }
 638
 639         /* 8 x (64/2) -> 256 x 16K -> 4MB */
 640         KKASSERT(i >= 0 && i < HAMMER2_BMAP_ELEMENTS);
 641
 642         /*
 643          * Optimize the buffer cache to avoid unnecessary read-before-write
 644          * operations.
 645          *
 646          * The device block size could be larger than the allocation size
 647          * so the actual bitmap test is somewhat more involved.  We have
 648          * to use a compatible buffer size for this operation.
 649          */
 650         if ((bmap->bitmapq[i] & bmmask) == 0 &&
 651             hammer2_devblksize(size) != size) {
 652                 size_t psize = hammer2_devblksize(size);
 653                 hammer2_off_t pmask = (hammer2_off_t)psize - 1;
 654                 int pbmradix = (hammer2_bitmap_t)2 <<
 655                                         (hammer2_devblkradix(radix) -
 656                                HAMMER2_FREEMAP_BLOCK_RADIX);
 657                 hammer2_bitmap_t pbmmask;
 658                 int pradix = hammer2_getradix(psize);
 659
 660                 pbmmask = (pbmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 661                         HAMMER2_BMAP_ALLONES :
 662                         ((hammer2_bitmap_t)1 << pbmradix) - 1;
 663                 while ((pbmmask & bmmask) == 0)
 664                         pbmmask <<= pbmradix;
 665
 666 #if 0
 667                 kprintf("%016jx mask %016jx %016jx %016jx (%zd/%zd)\n",
 668                         *basep + offset, bmap->bitmapq[i],
 669                         pbmmask, bmmask, size, psize);
 670 #endif
 671
 672                 if ((bmap->bitmapq[i] & pbmmask) == 0) {
 673                         hammer2_io_newq(hmp, HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 674                                         (*basep + (offset & ~pmask)) |
 675                                         pradix, psize);
 676                 }
 677         }
 678
 679 #if 0
 680         /*
 681          * When initializing a new inode segment also attempt to initialize
 682          * an adjacent segment.  Be careful not to index beyond the array
 683          * bounds.
 684          *
 685          * We do this to try to localize inode accesses to improve
 686          * directory scan rates.  XXX doesn't improve scan rates.
 687          */
 688         if (size == HAMMER2_INODE_BYTES) {
 689                 if (n & 1) {
 690                         if (bmap[-1].radix == 0 && bmap[-1].avail)
 691                                 bmap[-1].radix = radix;
 692                 } else {
 693                         if (bmap[1].radix == 0 && bmap[1].avail)
 694                                 bmap[1].radix = radix;
 695                 }
 696         }
 697 #endif
 698         /*
 699          * Calculate the bitmap-granular change in bgsize for the volume
 700          * header.  We cannot use the fine-grained change here because
 701          * the bulkfree code can't undo it.  If the bitmap element is already
 702          * marked allocated it has already been accounted for.
 703          */
 704         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
 705                 if (bmap->bitmapq[i] & bmmask)
 706                         bgsize = 0;
 707                 else
 708                         bgsize = HAMMER2_FREEMAP_BLOCK_SIZE;
 709         } else {
 710                 bgsize = size;
 711         }
 712
 713         /*
 714          * Adjust the bitmap, set the class (it might have been 0),
 715          * and available bytes, update the allocation offset (*basep)
 716          * from the L0 base to the actual offset.
 717          *
 718          * avail must reflect the bitmap-granular availability.  The allocator
 719          * tests will also check the linear iterator.
 720          */
 721         bmap->bitmapq[i] |= bmmask;
 722         bmap->class = class;
 723         bmap->avail -= bgsize;
 724         *basep += offset;
 725
 726         /*
 727          * Adjust the volume header's allocator_free parameter.  This
 728          * parameter has to be fixed up by bulkfree which has no way to
 729          * figure out sub-16K chunking, so it must be adjusted by the
 730          * bitmap-granular size.
 731          */
 732         if (bgsize) {
 733                 hammer2_voldata_lock(hmp);
 734                 hammer2_voldata_modify(hmp);
 735                 hmp->voldata.allocator_free -= bgsize;
 736                 hammer2_voldata_unlock(hmp);
 737         }
 738
 739         return(0);
 740 }
 741
 742 static
 743 void
 744 hammer2_freemap_init(hammer2_dev_t *hmp, hammer2_key_t key,
 745                      hammer2_chain_t *chain)
 746 {
 747         hammer2_off_t l1size;
 748         hammer2_off_t lokey;
 749         hammer2_off_t hikey;
 750         hammer2_bmap_data_t *bmap;
 751         int count;
 752
 753         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 754
 755         /*
 756          * Calculate the portion of the 2GB map that should be initialized
 757          * as free.  Portions below or after will be initialized as allocated.
 758          * SEGMASK-align the areas so we don't have to worry about sub-scans
 759          * or endianess when using memset.
 760          *
 761          * (1) Ensure that all statically allocated space from newfs_hammer2
 762          *     is marked allocated.
 763          *
 764          * (2) Ensure that the reserved area is marked allocated (typically
 765          *     the first 4MB of the 2GB area being represented).
 766          *
 767          * (3) Ensure that any trailing space at the end-of-volume is marked
 768          *     allocated.
 769          *
 770          * WARNING! It is possible for lokey to be larger than hikey if the
 771          *          entire 2GB segment is within the static allocation.
 772          */
 773         lokey = (hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
 774                 ~HAMMER2_SEGMASK64;
 775
 776         if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 777                   HAMMER2_ZONE_SEG64) {
 778                 lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 779                         HAMMER2_ZONE_SEG64;
 780         }
 781
 782         hikey = key + H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 783         if (hikey > hmp->voldata.volu_size) {
 784                 hikey = hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
 785         }
 786
 787         chain->bref.check.freemap.avail =
 788                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 789         bmap = &chain->data->bmdata[0];
 790
 791         for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 792                 if (key < lokey || key >= hikey) {
 793                         memset(bmap->bitmapq, -1,
 794                                sizeof(bmap->bitmapq));
 795                         bmap->avail = 0;
 796                         bmap->linear = HAMMER2_SEGSIZE;
 797                         chain->bref.check.freemap.avail -=
 798                                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 799                 } else {
 800                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 801                 }
 802                 key += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 803                 ++bmap;
 804         }
 805 }
 806
 807 /*
 808  * The current Level 1 freemap has been exhausted, iterate to the next
 809  * one, return ENOSPC if no freemaps remain.
 810  *
 811  * XXX this should rotate back to the beginning to handle freed-up space
 812  * XXX or use intermediate entries to locate free space. TODO
 813  */
 814 static int
 815 hammer2_freemap_iterate(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
 816                         hammer2_fiterate_t *iter)
 817 {
 818         hammer2_dev_t *hmp = (*parentp)->hmp;
 819
 820         iter->bnext &= ~(H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
 821         iter->bnext += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 822         if (iter->bnext >= hmp->voldata.volu_size) {
 823                 iter->bnext = 0;
 824                 if (++iter->loops == 2)
 825                         return (ENOSPC);
 826         }
 827         return(EAGAIN);
 828 }
 829
 830 /*
 831  * Adjust the bit-pattern for data in the freemap bitmap according to
 832  * (how).  This code is called from on-mount recovery to fixup (mark
 833  * as allocated) blocks whos freemap upates might not have been committed
 834  * in the last crash and is used by the bulk freemap scan to stage frees.
 835  *
 836  * WARNING! Cannot be called with a empty-data bref (radix == 0).
 837  *
 838  * XXX currently disabled when how == 0 (the normal real-time case).  At
 839  * the moment we depend on the bulk freescan to actually free blocks.  It
 840  * will still call this routine with a non-zero how to stage possible frees
 841  * and to do the actual free.
 842  */
 843 void
 844 hammer2_freemap_adjust(hammer2_dev_t *hmp, hammer2_blockref_t *bref,
 845                        int how)
 846 {
 847         hammer2_off_t data_off = bref->data_off;
 848         hammer2_chain_t *chain;
 849         hammer2_chain_t *parent;
 850         hammer2_bmap_data_t *bmap;
 851         hammer2_key_t key;
 852         hammer2_key_t key_dummy;
 853         hammer2_off_t l0size;
 854         hammer2_off_t l1size;
 855         hammer2_off_t l1mask;
 856         hammer2_tid_t mtid;
 857         hammer2_bitmap_t *bitmap;
 858         const hammer2_bitmap_t bmmask00 = 0;
 859         hammer2_bitmap_t bmmask01;
 860         hammer2_bitmap_t bmmask10;
 861         hammer2_bitmap_t bmmask11;
 862         size_t bytes;
 863         uint16_t class;
 864         int radix;
 865         int start;
 866         int count;
 867         int modified = 0;
 868         int cache_index = -1;
 869         int error;
 870         size_t bgsize = 0;
 871
 872         KKASSERT(how == HAMMER2_FREEMAP_DORECOVER);
 873
 874         mtid = hammer2_trans_sub(hmp->spmp);
 875
 876         radix = (int)data_off & HAMMER2_OFF_MASK_RADIX;
 877         KKASSERT(radix != 0);
 878         data_off &= ~HAMMER2_OFF_MASK_RADIX;
 879         KKASSERT(radix <= HAMMER2_RADIX_MAX);
 880
 881         if (radix)
 882                 bytes = (size_t)1 << radix;
 883         else
 884                 bytes = 0;
 885         class = (bref->type << 8) | hammer2_devblkradix(radix);
 886
 887         /*
 888          * We can't adjust the freemap for data allocations made by
 889          * newfs_hammer2.
 890          */
 891         if (data_off < hmp->voldata.allocator_beg)
 892                 return;
 893
 894         KKASSERT((data_off & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
 895
 896         /*
 897          * Lookup the level1 freemap chain.  The chain must exist.
 898          */
 899         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL1_RADIX);
 900         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 901         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 902         l1mask = l1size - 1;
 903
 904         parent = &hmp->fchain;
 905         hammer2_chain_ref(parent);
 906         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 907
 908         chain = hammer2_chain_lookup(&parent, &key_dummy, key, key + l1mask,
 909                                      &cache_index,
 910                                      HAMMER2_LOOKUP_ALWAYS |
 911                                      HAMMER2_LOOKUP_MATCHIND);
 912
 913         /*
 914          * Stop early if we are trying to free something but no leaf exists.
 915          */
 916         if (chain == NULL && how != HAMMER2_FREEMAP_DORECOVER) {
 917                 kprintf("hammer2_freemap_adjust: %016jx: no chain\n",
 918                         (intmax_t)bref->data_off);
 919                 goto done;
 920         }
 921         if (chain->error) {
 922                 kprintf("hammer2_freemap_adjust: %016jx: error %s\n",
 923                         (intmax_t)bref->data_off,
 924                         hammer2_error_str(chain->error));
 925                 hammer2_chain_unlock(chain);
 926                 hammer2_chain_drop(chain);
 927                 chain = NULL;
 928                 goto done;
 929         }
 930
 931         /*
 932          * Create any missing leaf(s) if we are doing a recovery (marking
 933          * the block(s) as being allocated instead of being freed).  Be sure
 934          * to initialize the auxillary freemap tracking info in the
 935          * bref.check.freemap structure.
 936          */
 937         if (chain == NULL && how == HAMMER2_FREEMAP_DORECOVER) {
 938                 error = hammer2_chain_create(&parent, &chain,
 939                                      hmp->spmp, HAMMER2_METH_DEFAULT,
 940                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
 941                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 942                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
 943                                      mtid, 0, 0);
 944
 945                 if (hammer2_debug & 0x0040) {
 946                         kprintf("fixup create chain %p %016jx:%d\n",
 947                                 chain, chain->bref.key, chain->bref.keybits);
 948                 }
 949
 950                 if (error == 0) {
 951                         hammer2_chain_modify(chain, mtid, 0, 0);
 952                         bzero(&chain->data->bmdata[0],
 953                               HAMMER2_FREEMAP_LEVELN_PSIZE);
 954                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
 955                         chain->bref.check.freemap.avail = l1size;
 956                         /* bref.methods should already be inherited */
 957
 958                         hammer2_freemap_init(hmp, key, chain);
 959                 }
 960                 /* XXX handle error */
 961         }
 962
 963 #if FREEMAP_DEBUG
 964         kprintf("FREEMAP ADJUST TYPE %d %016jx/%d DATA_OFF=%016jx\n",
 965                 chain->bref.type, chain->bref.key,
 966                 chain->bref.keybits, chain->bref.data_off);
 967 #endif
 968
 969         /*
 970          * Calculate the bitmask (runs in 2-bit pairs).
 971          */
 972         start = ((int)(data_off >> HAMMER2_FREEMAP_BLOCK_RADIX) & 15) * 2;
 973         bmmask01 = (hammer2_bitmap_t)1 << start;
 974         bmmask10 = (hammer2_bitmap_t)2 << start;
 975         bmmask11 = (hammer2_bitmap_t)3 << start;
 976
 977         /*
 978          * Fixup the bitmap.  Partial blocks cannot be fully freed unless
 979          * a bulk scan is able to roll them up.
 980          */
 981         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
 982                 count = 1;
 983                 if (how == HAMMER2_FREEMAP_DOREALFREE)
 984                         how = HAMMER2_FREEMAP_DOMAYFREE;
 985         } else {
 986                 count = 1 << (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
 987         }
 988
 989         /*
 990          * [re]load the bmap and bitmap pointers.  Each bmap entry covers
 991          * a 2MB swath.  The bmap itself (LEVEL1) covers 2GB.
 992          *
 993          * Be sure to reset the linear iterator to ensure that the adjustment
 994          * is not ignored.
 995          */
 996 again:
 997         bmap = &chain->data->bmdata[(int)(data_off >> HAMMER2_SEGRADIX) &
 998                                     (HAMMER2_FREEMAP_COUNT - 1)];
 999         bitmap = &bmap->bitmapq[(int)(data_off >> (HAMMER2_SEGRADIX - 3)) & 7];
1000
1001         if (modified)
1002                 bmap->linear = 0;
1003
1004         while (count) {
1005                 KKASSERT(bmmask11);
1006                 if (how == HAMMER2_FREEMAP_DORECOVER) {
1007                         /*
1008                          * Recovery request, mark as allocated.
1009                          */
1010                         if ((*bitmap & bmmask11) != bmmask11) {
1011                                 if (modified == 0) {
1012                                         hammer2_chain_modify(chain, mtid, 0, 0);
1013                                         modified = 1;
1014                                         goto again;
1015                                 }
1016                                 if ((*bitmap & bmmask11) == bmmask00) {
1017                                         bmap->avail -=
1018                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1019                                         bgsize += HAMMER2_FREEMAP_BLOCK_SIZE;
1020                                 }
1021                                 if (bmap->class == 0)
1022                                         bmap->class = class;
1023                                 *bitmap |= bmmask11;
1024                                 if (hammer2_debug & 0x0040) {
1025                                         kprintf("hammer2_freemap_recover: "
1026                                                 "fixup type=%02x "
1027                                                 "block=%016jx/%zd\n",
1028                                                 bref->type, data_off, bytes);
1029                                 }
1030                         } else {
1031                                 /*
1032                                 kprintf("hammer2_freemap_recover:  good "
1033                                         "type=%02x block=%016jx/%zd\n",
1034                                         bref->type, data_off, bytes);
1035                                 */
1036                         }
1037                 }
1038 #if 0
1039                 /*
1040                  * XXX this stuff doesn't work, avail is miscalculated and
1041                  * code 10 means something else now.
1042                  */
1043                 else if ((*bitmap & bmmask11) == bmmask11) {
1044                         /*
1045                          * Mayfree/Realfree request and bitmap is currently
1046                          * marked as being fully allocated.
1047                          */
1048                         if (!modified) {
1049                                 hammer2_chain_modify(chain, 0);
1050                                 modified = 1;
1051                                 goto again;
1052                         }
1053                         if (how == HAMMER2_FREEMAP_DOREALFREE)
1054                                 *bitmap &= ~bmmask11;
1055                         else
1056                                 *bitmap = (*bitmap & ~bmmask11) | bmmask10;
1057                 } else if ((*bitmap & bmmask11) == bmmask10) {
1058                         /*
1059                          * Mayfree/Realfree request and bitmap is currently
1060                          * marked as being possibly freeable.
1061                          */
1062                         if (how == HAMMER2_FREEMAP_DOREALFREE) {
1063                                 if (!modified) {
1064                                         hammer2_chain_modify(chain, 0);
1065                                         modified = 1;
1066                                         goto again;
1067                                 }
1068                                 *bitmap &= ~bmmask11;
1069                         }
1070                 } else {
1071                         /*
1072                          * 01 - Not implemented, currently illegal state
1073                          * 00 - Not allocated at all, illegal free.
1074                          */
1075                         panic("hammer2_freemap_adjust: "
1076                               "Illegal state %08x(%08x)",
1077                               *bitmap, *bitmap & bmmask11);
1078                 }
1079 #endif
1080                 --count;
1081                 bmmask01 <<= 2;
1082                 bmmask10 <<= 2;
1083                 bmmask11 <<= 2;
1084         }
1085 #if HAMMER2_BMAP_ELEMENTS != 8
1086 #error "hammer2_freemap.c: HAMMER2_BMAP_ELEMENTS expected to be 8"
1087 #endif
1088         if (how == HAMMER2_FREEMAP_DOREALFREE && modified) {
1089                 bmap->avail += 1 << radix;
1090                 KKASSERT(bmap->avail <= HAMMER2_SEGSIZE);
1091                 if (bmap->avail == HAMMER2_SEGSIZE &&
1092                     bmap->bitmapq[0] == 0 &&
1093                     bmap->bitmapq[1] == 0 &&
1094                     bmap->bitmapq[2] == 0 &&
1095                     bmap->bitmapq[3] == 0 &&
1096                     bmap->bitmapq[4] == 0 &&
1097                     bmap->bitmapq[5] == 0 &&
1098                     bmap->bitmapq[6] == 0 &&
1099                     bmap->bitmapq[7] == 0) {
1100                         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL0_RADIX);
1101                         kprintf("Freeseg %016jx\n", (intmax_t)key);
1102                         bmap->class = 0;
1103                 }
1104         }
1105
1106         /*
1107          * chain->bref.check.freemap.bigmask (XXX)
1108          *
1109          * Setting bigmask is a hint to the allocation code that there might
1110          * be something allocatable.  We also set this in recovery... it
1111          * doesn't hurt and we might want to use the hint for other validation
1112          * operations later on.
1113          */
1114         if (modified)
1115                 chain->bref.check.freemap.bigmask |= 1 << radix;
1116
1117         hammer2_chain_unlock(chain);
1118         hammer2_chain_drop(chain);
1119 done:
1120         hammer2_chain_unlock(parent);
1121         hammer2_chain_drop(parent);
1122
1123         if (bgsize) {
1124                 hammer2_voldata_lock(hmp);
1125                 hammer2_voldata_modify(hmp);
1126                 hmp->voldata.allocator_free -= bgsize;
1127                 hammer2_voldata_unlock(hmp);
1128         }
1129 }
1130
1131 /*
1132  * Validate the freemap, in three stages.
1133  *
1134  * stage-1      ALLOCATED     -> POSSIBLY FREE
1135  *              POSSIBLY FREE -> POSSIBLY FREE (type corrected)
1136  *
1137  *      This transitions bitmap entries from ALLOCATED to POSSIBLY FREE.
1138  *      The POSSIBLY FREE state does not mean that a block is actually free
1139  *      and may be transitioned back to ALLOCATED in stage-2.
1140  *
1141  *      This is typically done during normal filesystem operations when
1142  *      something is deleted or a block is replaced.
1143  *
1144  *      This is done by bulkfree in-bulk after a memory-bounded meta-data
1145  *      scan to try to determine what might be freeable.
1146  *
1147  *      This can be done unconditionally through a freemap scan when the
1148  *      intention is to brute-force recover the proper state of the freemap.
1149  *
1150  * stage-2      POSSIBLY FREE -> ALLOCATED      (scan metadata topology)
1151  *
1152  *      This is done by bulkfree during a meta-data scan to ensure that
1153  *      all blocks still actually allocated by the filesystem are marked
1154  *      as such.
1155  *
1156  *      NOTE! Live filesystem transitions to POSSIBLY FREE can occur while
1157  *            the bulkfree stage-2 and stage-3 is running.  The live filesystem
1158  *            will use the alternative POSSIBLY FREE type (2) to prevent
1159  *            stage-3 from improperly transitioning unvetted possibly-free
1160  *            blocks to FREE.
1161  *
1162  * stage-3      POSSIBLY FREE (type 1) -> FREE  (scan freemap)
1163  *
1164  *      This is done by bulkfree to finalize POSSIBLY FREE states.
1165  *
1166  */