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         int             relaxed;
  55 };
  56
  57 typedef struct hammer2_fiterate hammer2_fiterate_t;
  58
  59 static int hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
  60                         hammer2_blockref_t *bref, int radix,
  61                         hammer2_fiterate_t *iter, hammer2_tid_t mtid);
  62 static void hammer2_freemap_init(hammer2_dev_t *hmp,
  63                         hammer2_key_t key, hammer2_chain_t *chain);
  64 static int hammer2_bmap_alloc(hammer2_dev_t *hmp,
  65                         hammer2_bmap_data_t *bmap, uint16_t class,
  66                         int n, int sub_key, int radix, hammer2_key_t *basep);
  67 static int hammer2_freemap_iterate(hammer2_chain_t **parentp,
  68                         hammer2_chain_t **chainp,
  69                         hammer2_fiterate_t *iter);
  70
  71 static __inline
  72 int
  73 hammer2_freemapradix(int radix)
  74 {
  75         return(radix);
  76 }
  77
  78 /*
  79  * Calculate the device offset for the specified FREEMAP_NODE or FREEMAP_LEAF
  80  * bref.  Return a combined media offset and physical size radix.  Freemap
  81  * chains use fixed storage offsets in the 4MB reserved area at the
  82  * beginning of each 2GB zone
  83  *
  84  * XXX I made a mistake and made the reserved area begin at each LEVEL1 zone,
  85  *     which is on a 1GB demark.  This will eat a little more space but for
  86  *     now we retain compatibility and make FMZONEBASE every 1GB
  87  *
  88  *     (see same thing in hammer2_bulkfree.c near the top, as well as in
  89  *     newfs_hammer2).
  90  *
  91  * Rotate between four possibilities.  Theoretically this means we have three
  92  * good freemaps in case of a crash which we can use as a base for the fixup
  93  * scan at mount-time.
  94  */
  95 #define H2FMZONEBASE(key)       ((key) & ~HAMMER2_FREEMAP_LEVEL1_MASK)
  96 #define H2FMBASE(key, radix)    ((key) & ~(((hammer2_off_t)1 << (radix)) - 1))
  97 #define H2FMSHIFT(radix)        ((hammer2_off_t)1 << (radix))
  98
  99 static
 100 int
 101 hammer2_freemap_reserve(hammer2_chain_t *chain, int radix)
 102 {
 103         hammer2_blockref_t *bref = &chain->bref;
 104         hammer2_off_t off;
 105         int index;
 106         int index_inc;
 107         size_t bytes;
 108
 109         /*
 110          * Physical allocation size.
 111          */
 112         bytes = (size_t)1 << radix;
 113
 114         /*
 115          * Calculate block selection index 0..7 of current block.  If this
 116          * is the first allocation of the block (verses a modification of an
 117          * existing block), we use index 0, otherwise we use the next rotating
 118          * index.
 119          */
 120         if ((bref->data_off & ~HAMMER2_OFF_MASK_RADIX) == 0) {
 121                 index = 0;
 122         } else {
 123                 off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX &
 124                       (((hammer2_off_t)1 <<
 125                         HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
 126                 off = off / HAMMER2_PBUFSIZE;
 127                 KKASSERT(off >= HAMMER2_ZONE_FREEMAP_00 &&
 128                          off < HAMMER2_ZONE_FREEMAP_END);
 129                 index = (int)(off - HAMMER2_ZONE_FREEMAP_00) /
 130                         HAMMER2_ZONE_FREEMAP_INC;
 131                 KKASSERT(index >= 0 && index < HAMMER2_NFREEMAPS);
 132                 if (++index == HAMMER2_NFREEMAPS)
 133                         index = 0;
 134         }
 135
 136         /*
 137          * Calculate the block offset of the reserved block.  This will
 138          * point into the 4MB reserved area at the base of the appropriate
 139          * 2GB zone, once added to the FREEMAP_x selection above.
 140          */
 141         index_inc = index * HAMMER2_ZONE_FREEMAP_INC;
 142
 143         switch(bref->keybits) {
 144         /* case HAMMER2_FREEMAP_LEVEL6_RADIX: not applicable */
 145         case HAMMER2_FREEMAP_LEVEL5_RADIX:      /* 2EB */
 146                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 147                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 148                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL5_RADIX) +
 149                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 150                        HAMMER2_ZONEFM_LEVEL5) * HAMMER2_PBUFSIZE;
 151                 break;
 152         case HAMMER2_FREEMAP_LEVEL4_RADIX:      /* 2EB */
 153                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 154                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 155                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL4_RADIX) +
 156                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 157                        HAMMER2_ZONEFM_LEVEL4) * HAMMER2_PBUFSIZE;
 158                 break;
 159         case HAMMER2_FREEMAP_LEVEL3_RADIX:      /* 2PB */
 160                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 161                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 162                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL3_RADIX) +
 163                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 164                        HAMMER2_ZONEFM_LEVEL3) * HAMMER2_PBUFSIZE;
 165                 break;
 166         case HAMMER2_FREEMAP_LEVEL2_RADIX:      /* 2TB */
 167                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 168                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 169                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL2_RADIX) +
 170                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 171                        HAMMER2_ZONEFM_LEVEL2) * HAMMER2_PBUFSIZE;
 172                 break;
 173         case HAMMER2_FREEMAP_LEVEL1_RADIX:      /* 2GB */
 174                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
 175                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 176                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 177                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 178                        HAMMER2_ZONEFM_LEVEL1) * HAMMER2_PBUFSIZE;
 179                 break;
 180         default:
 181                 panic("freemap: bad radix(2) %p %d\n", bref, bref->keybits);
 182                 /* NOT REACHED */
 183                 off = (hammer2_off_t)-1;
 184                 break;
 185         }
 186         bref->data_off = off | radix;
 187 #if FREEMAP_DEBUG
 188         kprintf("FREEMAP BLOCK TYPE %d %016jx/%d DATA_OFF=%016jx\n",
 189                 bref->type, bref->key, bref->keybits, bref->data_off);
 190 #endif
 191         return (0);
 192 }
 193
 194 /*
 195  * Normal freemap allocator
 196  *
 197  * Use available hints to allocate space using the freemap.  Create missing
 198  * freemap infrastructure on-the-fly as needed (including marking initial
 199  * allocations using the iterator as allocated, instantiating new 2GB zones,
 200  * and dealing with the end-of-media edge case).
 201  *
 202  * ip and bpref are only used as a heuristic to determine locality of
 203  * reference.  bref->key may also be used heuristically.
 204  *
 205  * This function is a NOP if bytes is 0.
 206  */
 207 int
 208 hammer2_freemap_alloc(hammer2_chain_t *chain, size_t bytes)
 209 {
 210         hammer2_dev_t *hmp = chain->hmp;
 211         hammer2_blockref_t *bref = &chain->bref;
 212         hammer2_chain_t *parent;
 213         hammer2_tid_t mtid;
 214         int radix;
 215         int error;
 216         unsigned int hindex;
 217         hammer2_fiterate_t iter;
 218
 219         /*
 220          * If allocating or downsizing to zero we just get rid of whatever
 221          * data_off we had.
 222          */
 223         if (bytes == 0) {
 224                 chain->bref.data_off = 0;
 225                 return 0;
 226         }
 227
 228         mtid = hammer2_trans_sub(hmp->spmp);
 229
 230         /*
 231          * Validate the allocation size.  It must be a power of 2.
 232          *
 233          * For now require that the caller be aware of the minimum
 234          * allocation (1K).
 235          */
 236         radix = hammer2_getradix(bytes);
 237         KKASSERT((size_t)1 << radix == bytes);
 238
 239         if (bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
 240             bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
 241                 /*
 242                  * Freemap blocks themselves are assigned from the reserve
 243                  * area, not allocated from the freemap.
 244                  */
 245                 error = hammer2_freemap_reserve(chain, radix);
 246
 247                 return error;
 248         }
 249
 250         KKASSERT(bytes >= HAMMER2_ALLOC_MIN && bytes <= HAMMER2_ALLOC_MAX);
 251
 252         /*
 253          * Calculate the starting point for our allocation search.
 254          *
 255          * Each freemap leaf is dedicated to a specific freemap_radix.
 256          * The freemap_radix can be more fine-grained than the device buffer
 257          * radix which results in inodes being grouped together in their
 258          * own segment, terminal-data (16K or less) and initial indirect
 259          * block being grouped together, and then full-indirect and full-data
 260          * blocks (64K) being grouped together.
 261          *
 262          * The single most important aspect of this is the inode grouping
 263          * because that is what allows 'find' and 'ls' and other filesystem
 264          * topology operations to run fast.
 265          */
 266 #if 0
 267         if (bref->data_off & ~HAMMER2_OFF_MASK_RADIX)
 268                 bpref = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
 269         else if (trans->tmp_bpref)
 270                 bpref = trans->tmp_bpref;
 271         else if (trans->tmp_ip)
 272                 bpref = trans->tmp_ip->chain->bref.data_off;
 273         else
 274 #endif
 275         /*
 276          * Heuristic tracking index.  We would like one for each distinct
 277          * bref type if possible.  heur_freemap[] has room for two classes
 278          * for each type.  At a minimum we have to break-up our heuristic
 279          * by device block sizes.
 280          */
 281         hindex = hammer2_devblkradix(radix) - HAMMER2_MINIORADIX;
 282         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_NRADIX);
 283         hindex += bref->type * HAMMER2_FREEMAP_HEUR_NRADIX;
 284         hindex &= HAMMER2_FREEMAP_HEUR_TYPES * HAMMER2_FREEMAP_HEUR_NRADIX - 1;
 285         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_SIZE);
 286
 287         iter.bpref = hmp->heur_freemap[hindex];
 288         iter.relaxed = hmp->freemap_relaxed;
 289
 290         /*
 291          * Make sure bpref is in-bounds.  It's ok if bpref covers a zone's
 292          * reserved area, the try code will iterate past it.
 293          */
 294         if (iter.bpref > hmp->voldata.volu_size)
 295                 iter.bpref = hmp->voldata.volu_size - 1;
 296
 297         /*
 298          * Iterate the freemap looking for free space before and after.
 299          */
 300         parent = &hmp->fchain;
 301         hammer2_chain_ref(parent);
 302         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 303         error = HAMMER2_ERROR_EAGAIN;
 304         iter.bnext = iter.bpref;
 305         iter.loops = 0;
 306
 307         while (error == HAMMER2_ERROR_EAGAIN) {
 308                 error = hammer2_freemap_try_alloc(&parent, bref, radix,
 309                                                   &iter, mtid);
 310         }
 311         hmp->freemap_relaxed |= iter.relaxed;   /* heuristical, SMP race ok */
 312         hmp->heur_freemap[hindex] = iter.bnext;
 313         hammer2_chain_unlock(parent);
 314         hammer2_chain_drop(parent);
 315
 316         return (error);
 317 }
 318
 319 static int
 320 hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
 321                           hammer2_blockref_t *bref, int radix,
 322                           hammer2_fiterate_t *iter, hammer2_tid_t mtid)
 323 {
 324         hammer2_dev_t *hmp = (*parentp)->hmp;
 325         hammer2_off_t l0size;
 326         hammer2_off_t l1size;
 327         hammer2_off_t l1mask;
 328         hammer2_key_t key_dummy;
 329         hammer2_chain_t *chain;
 330         hammer2_off_t key;
 331         size_t bytes;
 332         uint16_t class;
 333         int error;
 334
 335         /*
 336          * Calculate the number of bytes being allocated, the number
 337          * of contiguous bits of bitmap being allocated, and the bitmap
 338          * mask.
 339          *
 340          * WARNING! cpu hardware may mask bits == 64 -> 0 and blow up the
 341          *          mask calculation.
 342          */
 343         bytes = (size_t)1 << radix;
 344         class = (bref->type << 8) | hammer2_devblkradix(radix);
 345
 346         /*
 347          * Lookup the level1 freemap chain, creating and initializing one
 348          * if necessary.  Intermediate levels will be created automatically
 349          * when necessary by hammer2_chain_create().
 350          */
 351         key = H2FMBASE(iter->bnext, HAMMER2_FREEMAP_LEVEL1_RADIX);
 352         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 353         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 354         l1mask = l1size - 1;
 355
 356         chain = hammer2_chain_lookup(parentp, &key_dummy, key, key + l1mask,
 357                                      &error,
 358                                      HAMMER2_LOOKUP_ALWAYS |
 359                                      HAMMER2_LOOKUP_MATCHIND);
 360
 361         if (chain == NULL) {
 362                 /*
 363                  * Create the missing leaf, be sure to initialize
 364                  * the auxillary freemap tracking information in
 365                  * the bref.check.freemap structure.
 366                  */
 367 #if 0
 368                 kprintf("freemap create L1 @ %016jx bpref %016jx\n",
 369                         key, iter->bpref);
 370 #endif
 371                 error = hammer2_chain_create(parentp, &chain,
 372                                      hmp->spmp, HAMMER2_METH_DEFAULT,
 373                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
 374                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 375                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
 376                                      mtid, 0, 0);
 377                 KKASSERT(error == 0);
 378                 if (error == 0) {
 379                         hammer2_chain_modify(chain, mtid, 0, 0);
 380                         bzero(&chain->data->bmdata[0],
 381                               HAMMER2_FREEMAP_LEVELN_PSIZE);
 382                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
 383                         chain->bref.check.freemap.avail = l1size;
 384                         /* bref.methods should already be inherited */
 385
 386                         hammer2_freemap_init(hmp, key, chain);
 387                 }
 388         } else if (chain->error) {
 389                 /*
 390                  * Error during lookup.
 391                  */
 392                 kprintf("hammer2_freemap_try_alloc: %016jx: error %s\n",
 393                         (intmax_t)bref->data_off,
 394                         hammer2_error_str(chain->error));
 395                 error = HAMMER2_ERROR_EIO;
 396         } else if ((chain->bref.check.freemap.bigmask &
 397                    ((size_t)1 << radix)) == 0) {
 398                 /*
 399                  * Already flagged as not having enough space
 400                  */
 401                 error = HAMMER2_ERROR_ENOSPC;
 402         } else {
 403                 /*
 404                  * Modify existing chain to setup for adjustment.
 405                  */
 406                 hammer2_chain_modify(chain, mtid, 0, 0);
 407         }
 408
 409         /*
 410          * Scan 4MB entries.
 411          */
 412         if (error == 0) {
 413                 hammer2_bmap_data_t *bmap;
 414                 hammer2_key_t base_key;
 415                 int count;
 416                 int start;
 417                 int n;
 418
 419                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
 420                 start = (int)((iter->bnext - key) >>
 421                               HAMMER2_FREEMAP_LEVEL0_RADIX);
 422                 KKASSERT(start >= 0 && start < HAMMER2_FREEMAP_COUNT);
 423                 hammer2_chain_modify(chain, mtid, 0, 0);
 424
 425                 error = HAMMER2_ERROR_ENOSPC;
 426                 for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 427                         int availchk;
 428
 429                         if (start + count >= HAMMER2_FREEMAP_COUNT &&
 430                             start - count < 0) {
 431                                 break;
 432                         }
 433
 434                         /*
 435                          * Calculate bmap pointer from thart starting index
 436                          * forwards.
 437                          *
 438                          * NOTE: bmap pointer is invalid if n >= FREEMAP_COUNT.
 439                          */
 440                         n = start + count;
 441                         bmap = &chain->data->bmdata[n];
 442
 443                         if (n >= HAMMER2_FREEMAP_COUNT) {
 444                                 availchk = 0;
 445                         } else if (bmap->avail) {
 446                                 availchk = 1;
 447                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
 448                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
 449                                 availchk = 1;
 450                         } else {
 451                                 availchk = 0;
 452                         }
 453
 454                         /*
 455                          * Try to allocate from a matching freemap class
 456                          * superblock.  If we are in relaxed mode we allocate
 457                          * from any freemap class superblock.
 458                          */
 459                         if (availchk &&
 460                             (bmap->class == 0 || bmap->class == class ||
 461                              iter->relaxed)) {
 462                                 base_key = key + n * l0size;
 463                                 error = hammer2_bmap_alloc(hmp, bmap,
 464                                                            class, n,
 465                                                            (int)bref->key,
 466                                                            radix,
 467                                                            &base_key);
 468                                 if (error != HAMMER2_ERROR_ENOSPC) {
 469                                         key = base_key;
 470                                         break;
 471                                 }
 472                         }
 473
 474                         /*
 475                          * Calculate bmap pointer from thart starting index
 476                          * backwards (locality).
 477                          *
 478                          * Must recalculate after potentially having called
 479                          * hammer2_bmap_alloc() above in case chain was
 480                          * reallocated.
 481                          *
 482                          * NOTE: bmap pointer is invalid if n < 0.
 483                          */
 484                         n = start - count;
 485                         bmap = &chain->data->bmdata[n];
 486                         if (n < 0) {
 487                                 availchk = 0;
 488                         } else if (bmap->avail) {
 489                                 availchk = 1;
 490                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
 491                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
 492                                 availchk = 1;
 493                         } else {
 494                                 availchk = 0;
 495                         }
 496
 497                         /*
 498                          * Try to allocate from a matching freemap class
 499                          * superblock.  If we are in relaxed mode we allocate
 500                          * from any freemap class superblock.
 501                          */
 502                         if (availchk &&
 503                             (bmap->class == 0 || bmap->class == class ||
 504                             iter->relaxed)) {
 505                                 base_key = key + n * l0size;
 506                                 error = hammer2_bmap_alloc(hmp, bmap,
 507                                                            class, n,
 508                                                            (int)bref->key,
 509                                                            radix,
 510                                                            &base_key);
 511                                 if (error != HAMMER2_ERROR_ENOSPC) {
 512                                         key = base_key;
 513                                         break;
 514                                 }
 515                         }
 516                 }
 517
 518                 /*
 519                  * We only know for sure that we can clear the bitmap bit
 520                  * if we scanned the entire array (start == 0).
 521                  */
 522                 if (error == HAMMER2_ERROR_ENOSPC && start == 0) {
 523                         chain->bref.check.freemap.bigmask &=
 524                                 (uint32_t)~((size_t)1 << radix);
 525                 }
 526                 /* XXX also scan down from original count */
 527         }
 528
 529         if (error == 0) {
 530                 /*
 531                  * Assert validity.  Must be beyond the static allocator used
 532                  * by newfs_hammer2 (and thus also beyond the aux area),
 533                  * not go past the volume size, and must not be in the
 534                  * reserved segment area for a zone.
 535                  */
 536                 KKASSERT(key >= hmp->voldata.allocator_beg &&
 537                          key + bytes <= hmp->voldata.volu_size);
 538                 KKASSERT((key & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
 539                 bref->data_off = key | radix;
 540
 541                 /*
 542                  * Record dedupability.  The dedup bits are cleared
 543                  * when bulkfree transitions the freemap from 11->10,
 544                  * and asserted to be clear on the 10->00 transition.
 545                  *
 546                  * We must record the bitmask with the chain locked
 547                  * at the time we set the allocation bits to avoid
 548                  * racing a bulkfree.
 549                  */
 550                 if (bref->type == HAMMER2_BREF_TYPE_DATA)
 551                         hammer2_io_dedup_set(hmp, bref);
 552 #if 0
 553                 kprintf("alloc cp=%p %016jx %016jx using %016jx\n",
 554                         chain,
 555                         bref->key, bref->data_off, chain->bref.data_off);
 556 #endif
 557         } else if (error == HAMMER2_ERROR_ENOSPC) {
 558                 /*
 559                  * Return EAGAIN with next iteration in iter->bnext, or
 560                  * return ENOSPC if the allocation map has been exhausted.
 561                  */
 562                 error = hammer2_freemap_iterate(parentp, &chain, iter);
 563         }
 564
 565         /*
 566          * Cleanup
 567          */
 568         if (chain) {
 569                 hammer2_chain_unlock(chain);
 570                 hammer2_chain_drop(chain);
 571         }
 572         return (error);
 573 }
 574
 575 /*
 576  * Allocate (1<<radix) bytes from the bmap whos base data offset is (*basep).
 577  *
 578  * If the linear iterator is mid-block we use it directly (the bitmap should
 579  * already be marked allocated), otherwise we search for a block in the
 580  * bitmap that fits the allocation request.
 581  *
 582  * A partial bitmap allocation sets the minimum bitmap granularity (16KB)
 583  * to fully allocated and adjusts the linear allocator to allow the
 584  * remaining space to be allocated.
 585  *
 586  * sub_key is the lower 32 bits of the chain->bref.key for the chain whos
 587  * bref is being allocated.  If the radix represents an allocation >= 16KB
 588  * (aka HAMMER2_FREEMAP_BLOCK_RADIX) we try to use this key to select the
 589  * blocks directly out of the bmap.
 590  */
 591 static
 592 int
 593 hammer2_bmap_alloc(hammer2_dev_t *hmp, hammer2_bmap_data_t *bmap,
 594                    uint16_t class, int n, int sub_key,
 595                    int radix, hammer2_key_t *basep)
 596 {
 597         size_t size;
 598         size_t bgsize;
 599         int bmradix;
 600         hammer2_bitmap_t bmmask;
 601         int offset;
 602         int i;
 603         int j;
 604
 605         /*
 606          * Take into account 2-bits per block when calculating bmradix.
 607          */
 608         size = (size_t)1 << radix;
 609
 610         if (radix <= HAMMER2_FREEMAP_BLOCK_RADIX) {
 611                 bmradix = 2;
 612                 /* (16K) 2 bits per allocation block */
 613         } else {
 614                 bmradix = (hammer2_bitmap_t)2 <<
 615                           (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
 616                 /* (32K-256K) 4, 8, 16, 32 bits per allocation block */
 617         }
 618
 619         /*
 620          * Use the linear iterator to pack small allocations, otherwise
 621          * fall-back to finding a free 16KB chunk.  The linear iterator
 622          * is only valid when *NOT* on a freemap chunking boundary (16KB).
 623          * If it is the bitmap must be scanned.  It can become invalid
 624          * once we pack to the boundary.  We adjust it after a bitmap
 625          * allocation only for sub-16KB allocations (so the perfectly good
 626          * previous value can still be used for fragments when 16KB+
 627          * allocations are made inbetween fragmentary allocations).
 628          *
 629          * Beware of hardware artifacts when bmradix == 64 (intermediate
 630          * result can wind up being '1' instead of '0' if hardware masks
 631          * bit-count & 63).
 632          *
 633          * NOTE: j needs to be even in the j= calculation.  As an artifact
 634          *       of the /2 division, our bitmask has to clear bit 0.
 635          *
 636          * NOTE: TODO this can leave little unallocatable fragments lying
 637          *       around.
 638          */
 639         if (((uint32_t)bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) + size <=
 640             HAMMER2_FREEMAP_BLOCK_SIZE &&
 641             (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) &&
 642             bmap->linear < HAMMER2_SEGSIZE) {
 643                 /*
 644                  * Use linear iterator if it is not block-aligned to avoid
 645                  * wasting space.
 646                  */
 647                 KKASSERT(bmap->linear >= 0 &&
 648                          bmap->linear + size <= HAMMER2_SEGSIZE &&
 649                          (bmap->linear & (HAMMER2_ALLOC_MIN - 1)) == 0);
 650                 offset = bmap->linear;
 651                 i = offset / (HAMMER2_SEGSIZE / 8);
 652                 j = (offset / (HAMMER2_FREEMAP_BLOCK_SIZE / 2)) & 30;
 653                 bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 654                          HAMMER2_BMAP_ALLONES :
 655                          ((hammer2_bitmap_t)1 << bmradix) - 1;
 656                 bmmask <<= j;
 657                 bmap->linear = offset + size;
 658         } else {
 659                 /*
 660                  * Try to index a starting point based on sub_key.  This
 661                  * attempts to restore sequential block ordering on-disk
 662                  * whenever possible, even if data is committed out of
 663                  * order.
 664                  *
 665                  * i - Index bitmapq[], full data range represented is
 666                  *     HAMMER2_BMAP_SIZE.
 667                  *
 668                  * j - Index within bitmapq[i], full data range represented is
 669                  *     HAMMER2_BMAP_INDEX_SIZE.
 670                  *
 671                  * WARNING!
 672                  */
 673                 i = -1;
 674                 j = -1;
 675
 676                 switch(class >> 8) {
 677                 case HAMMER2_BREF_TYPE_DATA:
 678                         if (radix >= HAMMER2_FREEMAP_BLOCK_RADIX) {
 679                                 i = (sub_key & HAMMER2_BMAP_MASK) /
 680                                     (HAMMER2_BMAP_SIZE / HAMMER2_BMAP_ELEMENTS);
 681                                 j = (sub_key & HAMMER2_BMAP_INDEX_MASK) /
 682                                     (HAMMER2_BMAP_INDEX_SIZE /
 683                                      HAMMER2_BMAP_BLOCKS_PER_ELEMENT);
 684                                 j = j * 2;
 685                         }
 686                         break;
 687                 case HAMMER2_BREF_TYPE_INODE:
 688                         break;
 689                 default:
 690                         break;
 691                 }
 692                 if (i >= 0) {
 693                         KKASSERT(i < HAMMER2_BMAP_ELEMENTS &&
 694                                  j < 2 * HAMMER2_BMAP_BLOCKS_PER_ELEMENT);
 695                         KKASSERT(j + bmradix <= HAMMER2_BMAP_BITS_PER_ELEMENT);
 696                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 697                                  HAMMER2_BMAP_ALLONES :
 698                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
 699                         bmmask <<= j;
 700
 701                         if ((bmap->bitmapq[i] & bmmask) == 0)
 702                                 goto success;
 703                 }
 704
 705                 /*
 706                  * General element scan.
 707                  *
 708                  * WARNING: (j) is iterating a bit index (by 2's)
 709                  */
 710                 for (i = 0; i < HAMMER2_BMAP_ELEMENTS; ++i) {
 711                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 712                                  HAMMER2_BMAP_ALLONES :
 713                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
 714                         for (j = 0;
 715                              j < HAMMER2_BMAP_BITS_PER_ELEMENT;
 716                              j += bmradix) {
 717                                 if ((bmap->bitmapq[i] & bmmask) == 0)
 718                                         goto success;
 719                                 bmmask <<= bmradix;
 720                         }
 721                 }
 722                 /*fragments might remain*/
 723                 /*KKASSERT(bmap->avail == 0);*/
 724                 return (HAMMER2_ERROR_ENOSPC);
 725 success:
 726                 offset = i * (HAMMER2_SEGSIZE / HAMMER2_BMAP_ELEMENTS) +
 727                          (j * (HAMMER2_FREEMAP_BLOCK_SIZE / 2));
 728                 if (size & HAMMER2_FREEMAP_BLOCK_MASK)
 729                         bmap->linear = offset + size;
 730         }
 731
 732         /* 8 x (64/2) -> 256 x 16K -> 4MB */
 733         KKASSERT(i >= 0 && i < HAMMER2_BMAP_ELEMENTS);
 734
 735         /*
 736          * Optimize the buffer cache to avoid unnecessary read-before-write
 737          * operations.
 738          *
 739          * The device block size could be larger than the allocation size
 740          * so the actual bitmap test is somewhat more involved.  We have
 741          * to use a compatible buffer size for this operation.
 742          */
 743         if ((bmap->bitmapq[i] & bmmask) == 0 &&
 744             hammer2_devblksize(size) != size) {
 745                 size_t psize = hammer2_devblksize(size);
 746                 hammer2_off_t pmask = (hammer2_off_t)psize - 1;
 747                 int pbmradix = (hammer2_bitmap_t)2 <<
 748                                         (hammer2_devblkradix(radix) -
 749                                HAMMER2_FREEMAP_BLOCK_RADIX);
 750                 hammer2_bitmap_t pbmmask;
 751                 int pradix = hammer2_getradix(psize);
 752
 753                 pbmmask = (pbmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 754                         HAMMER2_BMAP_ALLONES :
 755                         ((hammer2_bitmap_t)1 << pbmradix) - 1;
 756                 while ((pbmmask & bmmask) == 0)
 757                         pbmmask <<= pbmradix;
 758
 759 #if 0
 760                 kprintf("%016jx mask %016jx %016jx %016jx (%zd/%zd)\n",
 761                         *basep + offset, bmap->bitmapq[i],
 762                         pbmmask, bmmask, size, psize);
 763 #endif
 764
 765                 if ((bmap->bitmapq[i] & pbmmask) == 0) {
 766                         hammer2_io_t *dio;
 767
 768                         hammer2_io_newnz(hmp, class >> 8,
 769                                         (*basep + (offset & ~pmask)) |
 770                                         pradix, psize, &dio);
 771                         hammer2_io_putblk(&dio);
 772                 }
 773         }
 774
 775 #if 0
 776         /*
 777          * When initializing a new inode segment also attempt to initialize
 778          * an adjacent segment.  Be careful not to index beyond the array
 779          * bounds.
 780          *
 781          * We do this to try to localize inode accesses to improve
 782          * directory scan rates.  XXX doesn't improve scan rates.
 783          */
 784         if (size == HAMMER2_INODE_BYTES) {
 785                 if (n & 1) {
 786                         if (bmap[-1].radix == 0 && bmap[-1].avail)
 787                                 bmap[-1].radix = radix;
 788                 } else {
 789                         if (bmap[1].radix == 0 && bmap[1].avail)
 790                                 bmap[1].radix = radix;
 791                 }
 792         }
 793 #endif
 794         /*
 795          * Calculate the bitmap-granular change in bgsize for the volume
 796          * header.  We cannot use the fine-grained change here because
 797          * the bulkfree code can't undo it.  If the bitmap element is already
 798          * marked allocated it has already been accounted for.
 799          */
 800         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
 801                 if (bmap->bitmapq[i] & bmmask)
 802                         bgsize = 0;
 803                 else
 804                         bgsize = HAMMER2_FREEMAP_BLOCK_SIZE;
 805         } else {
 806                 bgsize = size;
 807         }
 808
 809         /*
 810          * Adjust the bitmap, set the class (it might have been 0),
 811          * and available bytes, update the allocation offset (*basep)
 812          * from the L0 base to the actual offset.
 813          *
 814          * Do not override the class if doing a relaxed class allocation.
 815          *
 816          * avail must reflect the bitmap-granular availability.  The allocator
 817          * tests will also check the linear iterator.
 818          */
 819         bmap->bitmapq[i] |= bmmask;
 820         if (bmap->class == 0)
 821                 bmap->class = class;
 822         bmap->avail -= bgsize;
 823         *basep += offset;
 824
 825         /*
 826          * Adjust the volume header's allocator_free parameter.  This
 827          * parameter has to be fixed up by bulkfree which has no way to
 828          * figure out sub-16K chunking, so it must be adjusted by the
 829          * bitmap-granular size.
 830          */
 831         if (bgsize) {
 832                 hammer2_voldata_lock(hmp);
 833                 hammer2_voldata_modify(hmp);
 834                 hmp->voldata.allocator_free -= bgsize;
 835                 hammer2_voldata_unlock(hmp);
 836         }
 837
 838         return(0);
 839 }
 840
 841 /*
 842  * Initialize a freemap for the storage area (in bytes) that begins at (key).
 843  */
 844 static
 845 void
 846 hammer2_freemap_init(hammer2_dev_t *hmp, hammer2_key_t key,
 847                      hammer2_chain_t *chain)
 848 {
 849         hammer2_off_t l1size;
 850         hammer2_off_t lokey;
 851         hammer2_off_t hikey;
 852         hammer2_bmap_data_t *bmap;
 853         int count;
 854
 855         /*
 856          * LEVEL1 is 1GB, there are two level1 1GB freemaps per 2GB zone.
 857          */
 858         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 859
 860         /*
 861          * Calculate the portion of the 1GB map that should be initialized
 862          * as free.  Portions below or after will be initialized as allocated.
 863          * SEGMASK-align the areas so we don't have to worry about sub-scans
 864          * or endianess when using memset.
 865          *
 866          * WARNING! It is possible for lokey to be larger than hikey if the
 867          *          entire 2GB segment is within the static allocation.
 868          */
 869         /*
 870          * (1) Ensure that all statically allocated space from newfs_hammer2
 871          *     is marked allocated, and take it up to the level1 base for
 872          *     this key.
 873          */
 874         lokey = (hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
 875                 ~HAMMER2_SEGMASK64;
 876         if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX))
 877                 lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX);
 878
 879         /*
 880          * (2) Ensure that the reserved area is marked allocated (typically
 881          *     the first 4MB of each 2GB area being represented).  Since
 882          *     each LEAF represents 1GB of storage and the zone is 2GB, we
 883          *     have to adjust lowkey upward every other LEAF sequentially.
 884          */
 885         if (lokey < H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64)
 886                 lokey = H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64;
 887
 888         /*
 889          * (3) Ensure that any trailing space at the end-of-volume is marked
 890          *     allocated.
 891          */
 892         hikey = key + H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 893         if (hikey > hmp->voldata.volu_size) {
 894                 hikey = hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
 895         }
 896
 897         /*
 898          * Heuristic highest possible value
 899          */
 900         chain->bref.check.freemap.avail =
 901                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 902         bmap = &chain->data->bmdata[0];
 903
 904         /*
 905          * Initialize bitmap (bzero'd by caller)
 906          */
 907         for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 908                 if (key < lokey || key >= hikey) {
 909                         memset(bmap->bitmapq, -1,
 910                                sizeof(bmap->bitmapq));
 911                         bmap->avail = 0;
 912                         bmap->linear = HAMMER2_SEGSIZE;
 913                         chain->bref.check.freemap.avail -=
 914                                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 915                 } else {
 916                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 917                 }
 918                 key += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
 919                 ++bmap;
 920         }
 921 }
 922
 923 /*
 924  * The current Level 1 freemap has been exhausted, iterate to the next
 925  * one, return ENOSPC if no freemaps remain.
 926  *
 927  * At least two loops are required.  If we are not in relaxed mode and
 928  * we run out of storage we enter relaxed mode and do a third loop.
 929  * The relaxed mode is recorded back in the hmp so once we enter the mode
 930  * we remain relaxed until stuff begins to get freed and only do 2 loops.
 931  *
 932  * XXX this should rotate back to the beginning to handle freed-up space
 933  * XXX or use intermediate entries to locate free space. TODO
 934  */
 935 static int
 936 hammer2_freemap_iterate(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
 937                         hammer2_fiterate_t *iter)
 938 {
 939         hammer2_dev_t *hmp = (*parentp)->hmp;
 940
 941         iter->bnext &= ~(H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
 942         iter->bnext += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
 943         if (iter->bnext >= hmp->voldata.volu_size) {
 944                 iter->bnext = 0;
 945                 if (++iter->loops >= 2) {
 946                         if (iter->relaxed == 0)
 947                                 iter->relaxed = 1;
 948                         else
 949                                 return (HAMMER2_ERROR_ENOSPC);
 950                 }
 951         }
 952         return(HAMMER2_ERROR_EAGAIN);
 953 }
 954
 955 /*
 956  * Adjust the bit-pattern for data in the freemap bitmap according to
 957  * (how).  This code is called from on-mount recovery to fixup (mark
 958  * as allocated) blocks whos freemap upates might not have been committed
 959  * in the last crash and is used by the bulk freemap scan to stage frees.
 960  *
 961  * WARNING! Cannot be called with a empty-data bref (radix == 0).
 962  *
 963  * XXX currently disabled when how == 0 (the normal real-time case).  At
 964  * the moment we depend on the bulk freescan to actually free blocks.  It
 965  * will still call this routine with a non-zero how to stage possible frees
 966  * and to do the actual free.
 967  */
 968 void
 969 hammer2_freemap_adjust(hammer2_dev_t *hmp, hammer2_blockref_t *bref,
 970                        int how)
 971 {
 972         hammer2_off_t data_off = bref->data_off;
 973         hammer2_chain_t *chain;
 974         hammer2_chain_t *parent;
 975         hammer2_bmap_data_t *bmap;
 976         hammer2_key_t key;
 977         hammer2_key_t key_dummy;
 978         hammer2_off_t l0size;
 979         hammer2_off_t l1size;
 980         hammer2_off_t l1mask;
 981         hammer2_tid_t mtid;
 982         hammer2_bitmap_t *bitmap;
 983         const hammer2_bitmap_t bmmask00 = 0;
 984         hammer2_bitmap_t bmmask01;
 985         hammer2_bitmap_t bmmask10;
 986         hammer2_bitmap_t bmmask11;
 987         size_t bytes;
 988         uint16_t class;
 989         int radix;
 990         int start;
 991         int count;
 992         int modified = 0;
 993         int error;
 994         size_t bgsize = 0;
 995
 996         KKASSERT(how == HAMMER2_FREEMAP_DORECOVER);
 997
 998         mtid = hammer2_trans_sub(hmp->spmp);
 999
1000         radix = (int)data_off & HAMMER2_OFF_MASK_RADIX;
1001         KKASSERT(radix != 0);
1002         data_off &= ~HAMMER2_OFF_MASK_RADIX;
1003         KKASSERT(radix <= HAMMER2_RADIX_MAX);
1004
1005         if (radix)
1006                 bytes = (size_t)1 << radix;
1007         else
1008                 bytes = 0;
1009         class = (bref->type << 8) | hammer2_devblkradix(radix);
1010
1011         /*
1012          * We can't adjust the freemap for data allocations made by
1013          * newfs_hammer2.
1014          */
1015         if (data_off < hmp->voldata.allocator_beg)
1016                 return;
1017
1018         KKASSERT((data_off & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
1019
1020         /*
1021          * Lookup the level1 freemap chain.  The chain must exist.
1022          */
1023         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL1_RADIX);
1024         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
1025         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
1026         l1mask = l1size - 1;
1027
1028         parent = &hmp->fchain;
1029         hammer2_chain_ref(parent);
1030         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1031
1032         chain = hammer2_chain_lookup(&parent, &key_dummy, key, key + l1mask,
1033                                      &error,
1034                                      HAMMER2_LOOKUP_ALWAYS |
1035                                      HAMMER2_LOOKUP_MATCHIND);
1036
1037         /*
1038          * Stop early if we are trying to free something but no leaf exists.
1039          */
1040         if (chain == NULL && how != HAMMER2_FREEMAP_DORECOVER) {
1041                 kprintf("hammer2_freemap_adjust: %016jx: no chain\n",
1042                         (intmax_t)bref->data_off);
1043                 goto done;
1044         }
1045         if (chain->error) {
1046                 kprintf("hammer2_freemap_adjust: %016jx: error %s\n",
1047                         (intmax_t)bref->data_off,
1048                         hammer2_error_str(chain->error));
1049                 hammer2_chain_unlock(chain);
1050                 hammer2_chain_drop(chain);
1051                 chain = NULL;
1052                 goto done;
1053         }
1054
1055         /*
1056          * Create any missing leaf(s) if we are doing a recovery (marking
1057          * the block(s) as being allocated instead of being freed).  Be sure
1058          * to initialize the auxillary freemap tracking info in the
1059          * bref.check.freemap structure.
1060          */
1061         if (chain == NULL && how == HAMMER2_FREEMAP_DORECOVER) {
1062                 error = hammer2_chain_create(&parent, &chain,
1063                                      hmp->spmp, HAMMER2_METH_DEFAULT,
1064                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
1065                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
1066                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
1067                                      mtid, 0, 0);
1068
1069                 if (hammer2_debug & 0x0040) {
1070                         kprintf("fixup create chain %p %016jx:%d\n",
1071                                 chain, chain->bref.key, chain->bref.keybits);
1072                 }
1073
1074                 if (error == 0) {
1075                         error = hammer2_chain_modify(chain, mtid, 0, 0);
1076                         KKASSERT(error == 0);
1077                         bzero(&chain->data->bmdata[0],
1078                               HAMMER2_FREEMAP_LEVELN_PSIZE);
1079                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
1080                         chain->bref.check.freemap.avail = l1size;
1081                         /* bref.methods should already be inherited */
1082
1083                         hammer2_freemap_init(hmp, key, chain);
1084                 }
1085                 /* XXX handle error */
1086         }
1087
1088 #if FREEMAP_DEBUG
1089         kprintf("FREEMAP ADJUST TYPE %d %016jx/%d DATA_OFF=%016jx\n",
1090                 chain->bref.type, chain->bref.key,
1091                 chain->bref.keybits, chain->bref.data_off);
1092 #endif
1093
1094         /*
1095          * Calculate the bitmask (runs in 2-bit pairs).
1096          */
1097         start = ((int)(data_off >> HAMMER2_FREEMAP_BLOCK_RADIX) & 15) * 2;
1098         bmmask01 = (hammer2_bitmap_t)1 << start;
1099         bmmask10 = (hammer2_bitmap_t)2 << start;
1100         bmmask11 = (hammer2_bitmap_t)3 << start;
1101
1102         /*
1103          * Fixup the bitmap.  Partial blocks cannot be fully freed unless
1104          * a bulk scan is able to roll them up.
1105          */
1106         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
1107                 count = 1;
1108                 if (how == HAMMER2_FREEMAP_DOREALFREE)
1109                         how = HAMMER2_FREEMAP_DOMAYFREE;
1110         } else {
1111                 count = 1 << (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
1112         }
1113
1114         /*
1115          * [re]load the bmap and bitmap pointers.  Each bmap entry covers
1116          * a 4MB swath.  The bmap itself (LEVEL1) covers 2GB.
1117          *
1118          * Be sure to reset the linear iterator to ensure that the adjustment
1119          * is not ignored.
1120          */
1121 again:
1122         bmap = &chain->data->bmdata[(int)(data_off >> HAMMER2_SEGRADIX) &
1123                                     (HAMMER2_FREEMAP_COUNT - 1)];
1124         bitmap = &bmap->bitmapq[(int)(data_off >> (HAMMER2_SEGRADIX - 3)) & 7];
1125
1126         if (modified)
1127                 bmap->linear = 0;
1128
1129         while (count) {
1130                 KKASSERT(bmmask11);
1131                 if (how == HAMMER2_FREEMAP_DORECOVER) {
1132                         /*
1133                          * Recovery request, mark as allocated.
1134                          */
1135                         if ((*bitmap & bmmask11) != bmmask11) {
1136                                 if (modified == 0) {
1137                                         hammer2_chain_modify(chain, mtid, 0, 0);
1138                                         modified = 1;
1139                                         goto again;
1140                                 }
1141                                 if ((*bitmap & bmmask11) == bmmask00) {
1142                                         bmap->avail -=
1143                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1144                                         bgsize += HAMMER2_FREEMAP_BLOCK_SIZE;
1145                                 }
1146                                 if (bmap->class == 0)
1147                                         bmap->class = class;
1148                                 *bitmap |= bmmask11;
1149                                 if (hammer2_debug & 0x0040) {
1150                                         kprintf("hammer2_freemap_recover: "
1151                                                 "fixup type=%02x "
1152                                                 "block=%016jx/%zd\n",
1153                                                 bref->type, data_off, bytes);
1154                                 }
1155                         } else {
1156                                 /*
1157                                 kprintf("hammer2_freemap_recover:  good "
1158                                         "type=%02x block=%016jx/%zd\n",
1159                                         bref->type, data_off, bytes);
1160                                 */
1161                         }
1162                 }
1163 #if 0
1164                 /*
1165                  * XXX this stuff doesn't work, avail is miscalculated and
1166                  * code 10 means something else now.
1167                  */
1168                 else if ((*bitmap & bmmask11) == bmmask11) {
1169                         /*
1170                          * Mayfree/Realfree request and bitmap is currently
1171                          * marked as being fully allocated.
1172                          */
1173                         if (!modified) {
1174                                 hammer2_chain_modify(chain, 0);
1175                                 modified = 1;
1176                                 goto again;
1177                         }
1178                         if (how == HAMMER2_FREEMAP_DOREALFREE)
1179                                 *bitmap &= ~bmmask11;
1180                         else
1181                                 *bitmap = (*bitmap & ~bmmask11) | bmmask10;
1182                 } else if ((*bitmap & bmmask11) == bmmask10) {
1183                         /*
1184                          * Mayfree/Realfree request and bitmap is currently
1185                          * marked as being possibly freeable.
1186                          */
1187                         if (how == HAMMER2_FREEMAP_DOREALFREE) {
1188                                 if (!modified) {
1189                                         hammer2_chain_modify(chain, 0);
1190                                         modified = 1;
1191                                         goto again;
1192                                 }
1193                                 *bitmap &= ~bmmask11;
1194                         }
1195                 } else {
1196                         /*
1197                          * 01 - Not implemented, currently illegal state
1198                          * 00 - Not allocated at all, illegal free.
1199                          */
1200                         panic("hammer2_freemap_adjust: "
1201                               "Illegal state %08x(%08x)",
1202                               *bitmap, *bitmap & bmmask11);
1203                 }
1204 #endif
1205                 --count;
1206                 bmmask01 <<= 2;
1207                 bmmask10 <<= 2;
1208                 bmmask11 <<= 2;
1209         }
1210 #if HAMMER2_BMAP_ELEMENTS != 8
1211 #error "hammer2_freemap.c: HAMMER2_BMAP_ELEMENTS expected to be 8"
1212 #endif
1213         if (how == HAMMER2_FREEMAP_DOREALFREE && modified) {
1214                 bmap->avail += 1 << radix;
1215                 KKASSERT(bmap->avail <= HAMMER2_SEGSIZE);
1216                 if (bmap->avail == HAMMER2_SEGSIZE &&
1217                     bmap->bitmapq[0] == 0 &&
1218                     bmap->bitmapq[1] == 0 &&
1219                     bmap->bitmapq[2] == 0 &&
1220                     bmap->bitmapq[3] == 0 &&
1221                     bmap->bitmapq[4] == 0 &&
1222                     bmap->bitmapq[5] == 0 &&
1223                     bmap->bitmapq[6] == 0 &&
1224                     bmap->bitmapq[7] == 0) {
1225                         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL0_RADIX);
1226                         kprintf("Freeseg %016jx\n", (intmax_t)key);
1227                         bmap->class = 0;
1228                 }
1229         }
1230
1231         /*
1232          * chain->bref.check.freemap.bigmask (XXX)
1233          *
1234          * Setting bigmask is a hint to the allocation code that there might
1235          * be something allocatable.  We also set this in recovery... it
1236          * doesn't hurt and we might want to use the hint for other validation
1237          * operations later on.
1238          *
1239          * We could calculate the largest possible allocation and set the
1240          * radii that could fit, but its easier just to set bigmask to -1.
1241          */
1242         if (modified) {
1243                 chain->bref.check.freemap.bigmask = -1;
1244                 hmp->freemap_relaxed = 0;       /* reset heuristic */
1245         }
1246
1247         hammer2_chain_unlock(chain);
1248         hammer2_chain_drop(chain);
1249 done:
1250         hammer2_chain_unlock(parent);
1251         hammer2_chain_drop(parent);
1252
1253         if (bgsize) {
1254                 hammer2_voldata_lock(hmp);
1255                 hammer2_voldata_modify(hmp);
1256                 hmp->voldata.allocator_free -= bgsize;
1257                 hammer2_voldata_unlock(hmp);
1258         }
1259 }
1260
1261 /*
1262  * Validate the freemap, in three stages.
1263  *
1264  * stage-1      ALLOCATED     -> POSSIBLY FREE
1265  *              POSSIBLY FREE -> POSSIBLY FREE (type corrected)
1266  *
1267  *      This transitions bitmap entries from ALLOCATED to POSSIBLY FREE.
1268  *      The POSSIBLY FREE state does not mean that a block is actually free
1269  *      and may be transitioned back to ALLOCATED in stage-2.
1270  *
1271  *      This is typically done during normal filesystem operations when
1272  *      something is deleted or a block is replaced.
1273  *
1274  *      This is done by bulkfree in-bulk after a memory-bounded meta-data
1275  *      scan to try to determine what might be freeable.
1276  *
1277  *      This can be done unconditionally through a freemap scan when the
1278  *      intention is to brute-force recover the proper state of the freemap.
1279  *
1280  * stage-2      POSSIBLY FREE -> ALLOCATED      (scan metadata topology)
1281  *
1282  *      This is done by bulkfree during a meta-data scan to ensure that
1283  *      all blocks still actually allocated by the filesystem are marked
1284  *      as such.
1285  *
1286  *      NOTE! Live filesystem transitions to POSSIBLY FREE can occur while
1287  *            the bulkfree stage-2 and stage-3 is running.  The live filesystem
1288  *            will use the alternative POSSIBLY FREE type (2) to prevent
1289  *            stage-3 from improperly transitioning unvetted possibly-free
1290  *            blocks to FREE.
1291  *
1292  * stage-3      POSSIBLY FREE (type 1) -> FREE  (scan freemap)
1293  *
1294  *      This is done by bulkfree to finalize POSSIBLY FREE states.
1295  *
1296  */