sys/vfs/hammer2/hammer2_freemap.c

   1 /*
   2  * Copyright (c) 2011-2018 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  * 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/mount.h>
  42 #include <sys/vnode.h>
  43 #include <sys/mountctl.h>
  44
  45 #include "hammer2.h"
  46
  47 #define FREEMAP_DEBUG   0
  48
  49 struct hammer2_fiterate {
  50         hammer2_off_t   bpref;
  51         hammer2_off_t   bnext;
  52         int             loops;
  53         int             relaxed;
  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 sub_key, 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 /*
  71  * Calculate the device offset for the specified FREEMAP_NODE or FREEMAP_LEAF
  72  * bref.  Return a combined media offset and physical size radix.  Freemap
  73  * chains use fixed storage offsets in the 4MB reserved area at the
  74  * beginning of each 2GB zone
  75  *
  76  * Rotate between four possibilities.  Theoretically this means we have three
  77  * good freemaps in case of a crash which we can use as a base for the fixup
  78  * scan at mount-time.
  79  */
  80 static
  81 int
  82 hammer2_freemap_reserve(hammer2_chain_t *chain, int radix)
  83 {
  84         hammer2_blockref_t *bref = &chain->bref;
  85         hammer2_off_t off;
  86         int index;
  87         int index_inc;
  88         size_t bytes;
  89
  90         /*
  91          * Physical allocation size.
  92          */
  93         bytes = (size_t)1 << radix;
  94
  95         /*
  96          * Calculate block selection index 0..7 of current block.  If this
  97          * is the first allocation of the block (verses a modification of an
  98          * existing block), we use index 0, otherwise we use the next rotating
  99          * index.
 100          */
 101         if ((bref->data_off & ~HAMMER2_OFF_MASK_RADIX) == 0) {
 102                 index = 0;
 103         } else {
 104                 off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX &
 105                       HAMMER2_SEGMASK;
 106                 off = off / HAMMER2_PBUFSIZE;
 107                 KKASSERT(off >= HAMMER2_ZONE_FREEMAP_00 &&
 108                          off < HAMMER2_ZONE_FREEMAP_END);
 109                 index = (int)(off - HAMMER2_ZONE_FREEMAP_00) /
 110                         HAMMER2_ZONE_FREEMAP_INC;
 111                 KKASSERT(index >= 0 && index < HAMMER2_NFREEMAPS);
 112                 if (++index == HAMMER2_NFREEMAPS)
 113                         index = 0;
 114         }
 115
 116         /*
 117          * Calculate the block offset of the reserved block.  This will
 118          * point into the 4MB reserved area at the base of the appropriate
 119          * 2GB zone, once added to the FREEMAP_x selection above.
 120          */
 121         index_inc = index * HAMMER2_ZONE_FREEMAP_INC;
 122
 123         switch(bref->keybits) {
 124         /* case HAMMER2_FREEMAP_LEVEL6_RADIX: not applicable */
 125         case HAMMER2_FREEMAP_LEVEL5_RADIX:      /* 4EB */
 126                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 127                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 128                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL5_RADIX) +
 129                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 130                        HAMMER2_ZONEFM_LEVEL5) * HAMMER2_PBUFSIZE;
 131                 break;
 132         case HAMMER2_FREEMAP_LEVEL4_RADIX:      /* 16PB */
 133                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 134                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 135                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL4_RADIX) +
 136                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 137                        HAMMER2_ZONEFM_LEVEL4) * HAMMER2_PBUFSIZE;
 138                 break;
 139         case HAMMER2_FREEMAP_LEVEL3_RADIX:      /* 64TB */
 140                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 141                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 142                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL3_RADIX) +
 143                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 144                        HAMMER2_ZONEFM_LEVEL3) * HAMMER2_PBUFSIZE;
 145                 break;
 146         case HAMMER2_FREEMAP_LEVEL2_RADIX:      /* 256GB */
 147                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
 148                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 149                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL2_RADIX) +
 150                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 151                        HAMMER2_ZONEFM_LEVEL2) * HAMMER2_PBUFSIZE;
 152                 break;
 153         case HAMMER2_FREEMAP_LEVEL1_RADIX:      /* 1GB */
 154                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
 155                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
 156                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
 157                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
 158                        HAMMER2_ZONEFM_LEVEL1) * HAMMER2_PBUFSIZE;
 159                 break;
 160         default:
 161                 panic("freemap: bad radix(2) %p %d\n", bref, bref->keybits);
 162                 /* NOT REACHED */
 163                 off = (hammer2_off_t)-1;
 164                 break;
 165         }
 166         bref->data_off = off | radix;
 167 #if FREEMAP_DEBUG
 168         kprintf("FREEMAP BLOCK TYPE %d %016jx/%d DATA_OFF=%016jx\n",
 169                 bref->type, bref->key, bref->keybits, bref->data_off);
 170 #endif
 171         return (0);
 172 }
 173
 174 /*
 175  * Normal freemap allocator
 176  *
 177  * Use available hints to allocate space using the freemap.  Create missing
 178  * freemap infrastructure on-the-fly as needed (including marking initial
 179  * allocations using the iterator as allocated, instantiating new 2GB zones,
 180  * and dealing with the end-of-media edge case).
 181  *
 182  * ip and bpref are only used as a heuristic to determine locality of
 183  * reference.  bref->key may also be used heuristically.
 184  *
 185  * This function is a NOP if bytes is 0.
 186  */
 187 int
 188 hammer2_freemap_alloc(hammer2_chain_t *chain, size_t bytes)
 189 {
 190         hammer2_dev_t *hmp = chain->hmp;
 191         hammer2_blockref_t *bref = &chain->bref;
 192         hammer2_chain_t *parent;
 193         hammer2_tid_t mtid;
 194         int radix;
 195         int error;
 196         unsigned int hindex;
 197         hammer2_fiterate_t iter;
 198
 199         /*
 200          * If allocating or downsizing to zero we just get rid of whatever
 201          * data_off we had.
 202          */
 203         if (bytes == 0) {
 204                 chain->bref.data_off = 0;
 205                 return 0;
 206         }
 207
 208         KKASSERT(hmp->spmp);
 209         mtid = hammer2_trans_sub(hmp->spmp);
 210
 211         /*
 212          * Validate the allocation size.  It must be a power of 2.
 213          *
 214          * For now require that the caller be aware of the minimum
 215          * allocation (1K).
 216          */
 217         radix = hammer2_getradix(bytes);
 218         KKASSERT((size_t)1 << radix == bytes);
 219
 220         if (bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
 221             bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
 222                 /*
 223                  * Freemap blocks themselves are assigned from the reserve
 224                  * area, not allocated from the freemap.
 225                  */
 226                 error = hammer2_freemap_reserve(chain, radix);
 227
 228                 return error;
 229         }
 230
 231         KKASSERT(bytes >= HAMMER2_ALLOC_MIN && bytes <= HAMMER2_ALLOC_MAX);
 232
 233         /*
 234          * Calculate the starting point for our allocation search.
 235          *
 236          * Each freemap leaf is dedicated to a specific freemap_radix.
 237          * The freemap_radix can be more fine-grained than the device buffer
 238          * radix which results in inodes being grouped together in their
 239          * own segment, terminal-data (16K or less) and initial indirect
 240          * block being grouped together, and then full-indirect and full-data
 241          * blocks (64K) being grouped together.
 242          *
 243          * The single most important aspect of this is the inode grouping
 244          * because that is what allows 'find' and 'ls' and other filesystem
 245          * topology operations to run fast.
 246          */
 247 #if 0
 248         if (bref->data_off & ~HAMMER2_OFF_MASK_RADIX)
 249                 bpref = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
 250         else if (trans->tmp_bpref)
 251                 bpref = trans->tmp_bpref;
 252         else if (trans->tmp_ip)
 253                 bpref = trans->tmp_ip->chain->bref.data_off;
 254         else
 255 #endif
 256         /*
 257          * Heuristic tracking index.  We would like one for each distinct
 258          * bref type if possible.  heur_freemap[] has room for two classes
 259          * for each type.  At a minimum we have to break-up our heuristic
 260          * by device block sizes.
 261          */
 262         hindex = HAMMER2_PBUFRADIX - HAMMER2_LBUFRADIX;
 263         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_NRADIX);
 264         hindex += bref->type * HAMMER2_FREEMAP_HEUR_NRADIX;
 265         hindex &= HAMMER2_FREEMAP_HEUR_TYPES * HAMMER2_FREEMAP_HEUR_NRADIX - 1;
 266         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_SIZE);
 267
 268         iter.bpref = hmp->heur_freemap[hindex];
 269         iter.relaxed = hmp->freemap_relaxed;
 270
 271         /*
 272          * Make sure bpref is in-bounds.  It's ok if bpref covers a zone's
 273          * reserved area, the try code will iterate past it.
 274          */
 275         if (iter.bpref > hmp->voldata.volu_size)
 276                 iter.bpref = hmp->voldata.volu_size - 1;
 277
 278         /*
 279          * Iterate the freemap looking for free space before and after.
 280          */
 281         parent = &hmp->fchain;
 282         hammer2_chain_ref(parent);
 283         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 284         error = HAMMER2_ERROR_EAGAIN;
 285         iter.bnext = iter.bpref;
 286         iter.loops = 0;
 287
 288         while (error == HAMMER2_ERROR_EAGAIN) {
 289                 error = hammer2_freemap_try_alloc(&parent, bref, radix,
 290                                                   &iter, mtid);
 291         }
 292         hmp->freemap_relaxed |= iter.relaxed;   /* heuristical, SMP race ok */
 293         hmp->heur_freemap[hindex] = iter.bnext;
 294         hammer2_chain_unlock(parent);
 295         hammer2_chain_drop(parent);
 296
 297         return (error);
 298 }
 299
 300 static int
 301 hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
 302                           hammer2_blockref_t *bref, int radix,
 303                           hammer2_fiterate_t *iter, hammer2_tid_t mtid)
 304 {
 305         hammer2_dev_t *hmp = (*parentp)->hmp;
 306         hammer2_off_t l0size;
 307         hammer2_off_t l1size;
 308         hammer2_off_t l1mask;
 309         hammer2_key_t key_dummy;
 310         hammer2_chain_t *chain;
 311         hammer2_off_t key;
 312         size_t bytes;
 313         uint16_t class;
 314         int error;
 315
 316         /*
 317          * Calculate the number of bytes being allocated, the number
 318          * of contiguous bits of bitmap being allocated, and the bitmap
 319          * mask.
 320          *
 321          * WARNING! cpu hardware may mask bits == 64 -> 0 and blow up the
 322          *          mask calculation.
 323          */
 324         bytes = (size_t)1 << radix;
 325         class = (bref->type << 8) | HAMMER2_PBUFRADIX;
 326
 327         /*
 328          * Lookup the level1 freemap chain, creating and initializing one
 329          * if necessary.  Intermediate levels will be created automatically
 330          * when necessary by hammer2_chain_create().
 331          */
 332         key = H2FMBASE(iter->bnext, HAMMER2_FREEMAP_LEVEL1_RADIX);
 333         l0size = HAMMER2_FREEMAP_LEVEL0_SIZE;
 334         l1size = HAMMER2_FREEMAP_LEVEL1_SIZE;
 335         l1mask = l1size - 1;
 336
 337         chain = hammer2_chain_lookup(parentp, &key_dummy, key, key + l1mask,
 338                                      &error,
 339                                      HAMMER2_LOOKUP_ALWAYS |
 340                                      HAMMER2_LOOKUP_MATCHIND);
 341
 342         if (chain == NULL) {
 343                 /*
 344                  * Create the missing leaf, be sure to initialize
 345                  * the auxillary freemap tracking information in
 346                  * the bref.check.freemap structure.
 347                  */
 348 #if 0
 349                 kprintf("freemap create L1 @ %016jx bpref %016jx\n",
 350                         key, iter->bpref);
 351 #endif
 352                 error = hammer2_chain_create(parentp, &chain, NULL, hmp->spmp,
 353                                      HAMMER2_METH_DEFAULT,
 354                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
 355                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
 356                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
 357                                      mtid, 0, 0);
 358                 KKASSERT(error == 0);
 359                 if (error == 0) {
 360                         hammer2_chain_modify(chain, mtid, 0, 0);
 361                         bzero(&chain->data->bmdata[0],
 362                               HAMMER2_FREEMAP_LEVELN_PSIZE);
 363                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
 364                         chain->bref.check.freemap.avail = l1size;
 365                         /* bref.methods should already be inherited */
 366
 367                         hammer2_freemap_init(hmp, key, chain);
 368                 }
 369         } else if (chain->error) {
 370                 /*
 371                  * Error during lookup.
 372                  */
 373                 kprintf("hammer2_freemap_try_alloc: %016jx: error %s\n",
 374                         (intmax_t)bref->data_off,
 375                         hammer2_error_str(chain->error));
 376                 error = HAMMER2_ERROR_EIO;
 377         } else if ((chain->bref.check.freemap.bigmask &
 378                    ((size_t)1 << radix)) == 0) {
 379                 /*
 380                  * Already flagged as not having enough space
 381                  */
 382                 error = HAMMER2_ERROR_ENOSPC;
 383         } else {
 384                 /*
 385                  * Modify existing chain to setup for adjustment.
 386                  */
 387                 hammer2_chain_modify(chain, mtid, 0, 0);
 388         }
 389
 390         /*
 391          * Scan 4MB entries.
 392          */
 393         if (error == 0) {
 394                 hammer2_bmap_data_t *bmap;
 395                 hammer2_key_t base_key;
 396                 int count;
 397                 int start;
 398                 int n;
 399
 400                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
 401                 start = (int)((iter->bnext - key) >>
 402                               HAMMER2_FREEMAP_LEVEL0_RADIX);
 403                 KKASSERT(start >= 0 && start < HAMMER2_FREEMAP_COUNT);
 404                 hammer2_chain_modify(chain, mtid, 0, 0);
 405
 406                 error = HAMMER2_ERROR_ENOSPC;
 407                 for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 408                         int availchk;
 409
 410                         if (start + count >= HAMMER2_FREEMAP_COUNT &&
 411                             start - count < 0) {
 412                                 break;
 413                         }
 414
 415                         /*
 416                          * Calculate bmap pointer from thart starting index
 417                          * forwards.
 418                          *
 419                          * NOTE: bmap pointer is invalid if n >= FREEMAP_COUNT.
 420                          */
 421                         n = start + count;
 422                         bmap = &chain->data->bmdata[n];
 423
 424                         if (n >= HAMMER2_FREEMAP_COUNT) {
 425                                 availchk = 0;
 426                         } else if (bmap->avail) {
 427                                 availchk = 1;
 428                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
 429                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
 430                                 availchk = 1;
 431                         } else {
 432                                 availchk = 0;
 433                         }
 434
 435                         /*
 436                          * Try to allocate from a matching freemap class
 437                          * superblock.  If we are in relaxed mode we allocate
 438                          * from any freemap class superblock.
 439                          */
 440                         if (availchk &&
 441                             (bmap->class == 0 || bmap->class == class ||
 442                              iter->relaxed)) {
 443                                 base_key = key + n * l0size;
 444                                 error = hammer2_bmap_alloc(hmp, bmap,
 445                                                            class, n,
 446                                                            (int)bref->key,
 447                                                            radix,
 448                                                            &base_key);
 449                                 if (error != HAMMER2_ERROR_ENOSPC) {
 450                                         key = base_key;
 451                                         break;
 452                                 }
 453                         }
 454
 455                         /*
 456                          * Calculate bmap pointer from thart starting index
 457                          * backwards (locality).
 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                         /*
 479                          * Try to allocate from a matching freemap class
 480                          * superblock.  If we are in relaxed mode we allocate
 481                          * from any freemap class superblock.
 482                          */
 483                         if (availchk &&
 484                             (bmap->class == 0 || bmap->class == class ||
 485                             iter->relaxed)) {
 486                                 base_key = key + n * l0size;
 487                                 error = hammer2_bmap_alloc(hmp, bmap,
 488                                                            class, n,
 489                                                            (int)bref->key,
 490                                                            radix,
 491                                                            &base_key);
 492                                 if (error != HAMMER2_ERROR_ENOSPC) {
 493                                         key = base_key;
 494                                         break;
 495                                 }
 496                         }
 497                 }
 498
 499                 /*
 500                  * We only know for sure that we can clear the bitmap bit
 501                  * if we scanned the entire array (start == 0).
 502                  */
 503                 if (error == HAMMER2_ERROR_ENOSPC && start == 0) {
 504                         chain->bref.check.freemap.bigmask &=
 505                                 (uint32_t)~((size_t)1 << radix);
 506                 }
 507                 /* XXX also scan down from original count */
 508         }
 509
 510         if (error == 0) {
 511                 /*
 512                  * Assert validity.  Must be beyond the static allocator used
 513                  * by newfs_hammer2 (and thus also beyond the aux area),
 514                  * not go past the volume size, and must not be in the
 515                  * reserved segment area for a zone.
 516                  */
 517                 KKASSERT(key >= hmp->voldata.allocator_beg &&
 518                          key + bytes <= hmp->voldata.volu_size);
 519                 KKASSERT((key & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
 520                 bref->data_off = key | radix;
 521
 522                 /*
 523                  * Record dedupability.  The dedup bits are cleared
 524                  * when bulkfree transitions the freemap from 11->10,
 525                  * and asserted to be clear on the 10->00 transition.
 526                  *
 527                  * We must record the bitmask with the chain locked
 528                  * at the time we set the allocation bits to avoid
 529                  * racing a bulkfree.
 530                  */
 531                 if (bref->type == HAMMER2_BREF_TYPE_DATA)
 532                         hammer2_io_dedup_set(hmp, bref);
 533 #if 0
 534                 kprintf("alloc cp=%p %016jx %016jx using %016jx\n",
 535                         chain,
 536                         bref->key, bref->data_off, chain->bref.data_off);
 537 #endif
 538         } else if (error == HAMMER2_ERROR_ENOSPC) {
 539                 /*
 540                  * Return EAGAIN with next iteration in iter->bnext, or
 541                  * return ENOSPC if the allocation map has been exhausted.
 542                  */
 543                 error = hammer2_freemap_iterate(parentp, &chain, iter);
 544         }
 545
 546         /*
 547          * Cleanup
 548          */
 549         if (chain) {
 550                 hammer2_chain_unlock(chain);
 551                 hammer2_chain_drop(chain);
 552         }
 553         return (error);
 554 }
 555
 556 /*
 557  * Allocate (1<<radix) bytes from the bmap whos base data offset is (*basep).
 558  *
 559  * If the linear iterator is mid-block we use it directly (the bitmap should
 560  * already be marked allocated), otherwise we search for a block in the
 561  * bitmap that fits the allocation request.
 562  *
 563  * A partial bitmap allocation sets the minimum bitmap granularity (16KB)
 564  * to fully allocated and adjusts the linear allocator to allow the
 565  * remaining space to be allocated.
 566  *
 567  * sub_key is the lower 32 bits of the chain->bref.key for the chain whos
 568  * bref is being allocated.  If the radix represents an allocation >= 16KB
 569  * (aka HAMMER2_FREEMAP_BLOCK_RADIX) we try to use this key to select the
 570  * blocks directly out of the bmap.
 571  */
 572 static
 573 int
 574 hammer2_bmap_alloc(hammer2_dev_t *hmp, hammer2_bmap_data_t *bmap,
 575                    uint16_t class, int n, int sub_key,
 576                    int radix, hammer2_key_t *basep)
 577 {
 578         size_t size;
 579         size_t bgsize;
 580         int bmradix;
 581         hammer2_bitmap_t bmmask;
 582         int offset;
 583         int i;
 584         int j;
 585
 586         /*
 587          * Take into account 2-bits per block when calculating bmradix.
 588          */
 589         size = (size_t)1 << radix;
 590
 591         if (radix <= HAMMER2_FREEMAP_BLOCK_RADIX) {
 592                 bmradix = 2;
 593                 /* (16K) 2 bits per allocation block */
 594         } else {
 595                 bmradix = (hammer2_bitmap_t)2 <<
 596                           (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
 597                 /* (32K-256K) 4, 8, 16, 32 bits per allocation block */
 598         }
 599
 600         /*
 601          * Use the linear iterator to pack small allocations, otherwise
 602          * fall-back to finding a free 16KB chunk.  The linear iterator
 603          * is only valid when *NOT* on a freemap chunking boundary (16KB).
 604          * If it is the bitmap must be scanned.  It can become invalid
 605          * once we pack to the boundary.  We adjust it after a bitmap
 606          * allocation only for sub-16KB allocations (so the perfectly good
 607          * previous value can still be used for fragments when 16KB+
 608          * allocations are made inbetween fragmentary allocations).
 609          *
 610          * Beware of hardware artifacts when bmradix == 64 (intermediate
 611          * result can wind up being '1' instead of '0' if hardware masks
 612          * bit-count & 63).
 613          *
 614          * NOTE: j needs to be even in the j= calculation.  As an artifact
 615          *       of the /2 division, our bitmask has to clear bit 0.
 616          *
 617          * NOTE: TODO this can leave little unallocatable fragments lying
 618          *       around.
 619          */
 620         if (((uint32_t)bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) + size <=
 621             HAMMER2_FREEMAP_BLOCK_SIZE &&
 622             (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) &&
 623             bmap->linear < HAMMER2_SEGSIZE) {
 624                 /*
 625                  * Use linear iterator if it is not block-aligned to avoid
 626                  * wasting space.
 627                  *
 628                  * Calculate the bitmapq[] index (i) and calculate the
 629                  * shift count within the 64-bit bitmapq[] entry.
 630                  *
 631                  * The freemap block size is 16KB, but each bitmap
 632                  * entry is two bits so use a little trick to get
 633                  * a (j) shift of 0, 2, 4, ... 62 in 16KB chunks.
 634                  */
 635                 KKASSERT(bmap->linear >= 0 &&
 636                          bmap->linear + size <= HAMMER2_SEGSIZE &&
 637                          (bmap->linear & (HAMMER2_ALLOC_MIN - 1)) == 0);
 638                 offset = bmap->linear;
 639                 i = offset / (HAMMER2_SEGSIZE / HAMMER2_BMAP_ELEMENTS);
 640                 j = (offset / (HAMMER2_FREEMAP_BLOCK_SIZE / 2)) & 62;
 641                 bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 642                          HAMMER2_BMAP_ALLONES :
 643                          ((hammer2_bitmap_t)1 << bmradix) - 1;
 644                 bmmask <<= j;
 645                 bmap->linear = offset + size;
 646         } else {
 647                 /*
 648                  * Try to index a starting point based on sub_key.  This
 649                  * attempts to restore sequential block ordering on-disk
 650                  * whenever possible, even if data is committed out of
 651                  * order.
 652                  *
 653                  * i - Index bitmapq[], full data range represented is
 654                  *     HAMMER2_BMAP_SIZE.
 655                  *
 656                  * j - Index within bitmapq[i], full data range represented is
 657                  *     HAMMER2_BMAP_INDEX_SIZE.
 658                  *
 659                  * WARNING!
 660                  */
 661                 i = -1;
 662                 j = -1;
 663
 664                 switch(class >> 8) {
 665                 case HAMMER2_BREF_TYPE_DATA:
 666                         if (radix >= HAMMER2_FREEMAP_BLOCK_RADIX) {
 667                                 i = (sub_key & HAMMER2_BMAP_MASK) /
 668                                     (HAMMER2_BMAP_SIZE / HAMMER2_BMAP_ELEMENTS);
 669                                 j = (sub_key & HAMMER2_BMAP_INDEX_MASK) /
 670                                     (HAMMER2_BMAP_INDEX_SIZE /
 671                                      HAMMER2_BMAP_BLOCKS_PER_ELEMENT);
 672                                 j = j * 2;
 673                         }
 674                         break;
 675                 case HAMMER2_BREF_TYPE_INODE:
 676                         break;
 677                 default:
 678                         break;
 679                 }
 680                 if (i >= 0) {
 681                         KKASSERT(i < HAMMER2_BMAP_ELEMENTS &&
 682                                  j < 2 * HAMMER2_BMAP_BLOCKS_PER_ELEMENT);
 683                         KKASSERT(j + bmradix <= HAMMER2_BMAP_BITS_PER_ELEMENT);
 684                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 685                                  HAMMER2_BMAP_ALLONES :
 686                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
 687                         bmmask <<= j;
 688
 689                         if ((bmap->bitmapq[i] & bmmask) == 0)
 690                                 goto success;
 691                 }
 692
 693                 /*
 694                  * General element scan.
 695                  *
 696                  * WARNING: (j) is iterating a bit index (by 2's)
 697                  */
 698                 for (i = 0; i < HAMMER2_BMAP_ELEMENTS; ++i) {
 699                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 700                                  HAMMER2_BMAP_ALLONES :
 701                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
 702                         for (j = 0;
 703                              j < HAMMER2_BMAP_BITS_PER_ELEMENT;
 704                              j += bmradix) {
 705                                 if ((bmap->bitmapq[i] & bmmask) == 0)
 706                                         goto success;
 707                                 bmmask <<= bmradix;
 708                         }
 709                 }
 710                 /*fragments might remain*/
 711                 /*KKASSERT(bmap->avail == 0);*/
 712                 return (HAMMER2_ERROR_ENOSPC);
 713 success:
 714                 offset = i * (HAMMER2_SEGSIZE / HAMMER2_BMAP_ELEMENTS) +
 715                          (j * (HAMMER2_FREEMAP_BLOCK_SIZE / 2));
 716                 if (size & HAMMER2_FREEMAP_BLOCK_MASK)
 717                         bmap->linear = offset + size;
 718         }
 719
 720         /* 8 x (64/2) -> 256 x 16K -> 4MB */
 721         KKASSERT(i >= 0 && i < HAMMER2_BMAP_ELEMENTS);
 722
 723         /*
 724          * Optimize the buffer cache to avoid unnecessary read-before-write
 725          * operations.
 726          *
 727          * The device block size could be larger than the allocation size
 728          * so the actual bitmap test is somewhat more involved.  We have
 729          * to use a compatible buffer size for this operation.
 730          */
 731         if ((bmap->bitmapq[i] & bmmask) == 0 &&
 732             HAMMER2_PBUFSIZE != size) {
 733                 size_t psize = HAMMER2_PBUFSIZE;
 734                 hammer2_off_t pmask = (hammer2_off_t)psize - 1;
 735                 int pbmradix = (hammer2_bitmap_t)2 <<
 736                                         (HAMMER2_PBUFRADIX -
 737                                HAMMER2_FREEMAP_BLOCK_RADIX);
 738                 hammer2_bitmap_t pbmmask;
 739                 int pradix = hammer2_getradix(psize);
 740
 741                 pbmmask = (pbmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
 742                         HAMMER2_BMAP_ALLONES :
 743                         ((hammer2_bitmap_t)1 << pbmradix) - 1;
 744                 while ((pbmmask & bmmask) == 0)
 745                         pbmmask <<= pbmradix;
 746
 747 #if 0
 748                 kprintf("%016jx mask %016jx %016jx %016jx (%zd/%zd)\n",
 749                         *basep + offset, bmap->bitmapq[i],
 750                         pbmmask, bmmask, size, psize);
 751 #endif
 752
 753                 if ((bmap->bitmapq[i] & pbmmask) == 0) {
 754                         hammer2_io_t *dio;
 755
 756                         hammer2_io_newnz(hmp, class >> 8,
 757                                         (*basep + (offset & ~pmask)) |
 758                                         pradix, psize, &dio);
 759                         hammer2_io_putblk(&dio);
 760                 }
 761         }
 762
 763 #if 0
 764         /*
 765          * When initializing a new inode segment also attempt to initialize
 766          * an adjacent segment.  Be careful not to index beyond the array
 767          * bounds.
 768          *
 769          * We do this to try to localize inode accesses to improve
 770          * directory scan rates.  XXX doesn't improve scan rates.
 771          */
 772         if (size == HAMMER2_INODE_BYTES) {
 773                 if (n & 1) {
 774                         if (bmap[-1].radix == 0 && bmap[-1].avail)
 775                                 bmap[-1].radix = radix;
 776                 } else {
 777                         if (bmap[1].radix == 0 && bmap[1].avail)
 778                                 bmap[1].radix = radix;
 779                 }
 780         }
 781 #endif
 782         /*
 783          * Calculate the bitmap-granular change in bgsize for the volume
 784          * header.  We cannot use the fine-grained change here because
 785          * the bulkfree code can't undo it.  If the bitmap element is already
 786          * marked allocated it has already been accounted for.
 787          */
 788         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
 789                 if (bmap->bitmapq[i] & bmmask)
 790                         bgsize = 0;
 791                 else
 792                         bgsize = HAMMER2_FREEMAP_BLOCK_SIZE;
 793         } else {
 794                 bgsize = size;
 795         }
 796
 797         /*
 798          * Adjust the bitmap, set the class (it might have been 0),
 799          * and available bytes, update the allocation offset (*basep)
 800          * from the L0 base to the actual offset.
 801          *
 802          * Do not override the class if doing a relaxed class allocation.
 803          *
 804          * avail must reflect the bitmap-granular availability.  The allocator
 805          * tests will also check the linear iterator.
 806          */
 807         bmap->bitmapq[i] |= bmmask;
 808         if (bmap->class == 0)
 809                 bmap->class = class;
 810         bmap->avail -= bgsize;
 811         *basep += offset;
 812
 813         /*
 814          * Adjust the volume header's allocator_free parameter.  This
 815          * parameter has to be fixed up by bulkfree which has no way to
 816          * figure out sub-16K chunking, so it must be adjusted by the
 817          * bitmap-granular size.
 818          */
 819         if (bgsize) {
 820                 hammer2_voldata_lock(hmp);
 821                 hammer2_voldata_modify(hmp);
 822                 hmp->voldata.allocator_free -= bgsize;
 823                 hammer2_voldata_unlock(hmp);
 824         }
 825
 826         return(0);
 827 }
 828
 829 /*
 830  * Initialize a freemap for the storage area (in bytes) that begins at (key).
 831  */
 832 static
 833 void
 834 hammer2_freemap_init(hammer2_dev_t *hmp, hammer2_key_t key,
 835                      hammer2_chain_t *chain)
 836 {
 837         hammer2_off_t l1size;
 838         hammer2_off_t lokey;
 839         hammer2_off_t hikey;
 840         hammer2_bmap_data_t *bmap;
 841         int count;
 842
 843         /*
 844          * LEVEL1 is 1GB, there are two level1 1GB freemaps per 2GB zone.
 845          */
 846         l1size = HAMMER2_FREEMAP_LEVEL1_SIZE;
 847
 848         /*
 849          * Calculate the portion of the 1GB map that should be initialized
 850          * as free.  Portions below or after will be initialized as allocated.
 851          * SEGMASK-align the areas so we don't have to worry about sub-scans
 852          * or endianess when using memset.
 853          *
 854          * WARNING! It is possible for lokey to be larger than hikey if the
 855          *          entire 2GB segment is within the static allocation.
 856          */
 857         /*
 858          * (1) Ensure that all statically allocated space from newfs_hammer2
 859          *     is marked allocated, and take it up to the level1 base for
 860          *     this key.
 861          */
 862         lokey = (hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
 863                 ~HAMMER2_SEGMASK64;
 864         if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX))
 865                 lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX);
 866
 867         /*
 868          * (2) Ensure that the reserved area is marked allocated (typically
 869          *     the first 4MB of each 2GB area being represented).  Since
 870          *     each LEAF represents 1GB of storage and the zone is 2GB, we
 871          *     have to adjust lowkey upward every other LEAF sequentially.
 872          */
 873         if (lokey < H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64)
 874                 lokey = H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64;
 875
 876         /*
 877          * (3) Ensure that any trailing space at the end-of-volume is marked
 878          *     allocated.
 879          */
 880         hikey = key + HAMMER2_FREEMAP_LEVEL1_SIZE;
 881         if (hikey > hmp->voldata.volu_size) {
 882                 hikey = hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
 883         }
 884
 885         /*
 886          * Heuristic highest possible value
 887          */
 888         chain->bref.check.freemap.avail = HAMMER2_FREEMAP_LEVEL1_SIZE;
 889         bmap = &chain->data->bmdata[0];
 890
 891         /*
 892          * Initialize bitmap (bzero'd by caller)
 893          */
 894         for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
 895                 if (key < lokey || key >= hikey) {
 896                         memset(bmap->bitmapq, -1,
 897                                sizeof(bmap->bitmapq));
 898                         bmap->avail = 0;
 899                         bmap->linear = HAMMER2_SEGSIZE;
 900                         chain->bref.check.freemap.avail -=
 901                                 HAMMER2_FREEMAP_LEVEL0_SIZE;
 902                 } else {
 903                         bmap->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
 904                 }
 905                 key += HAMMER2_FREEMAP_LEVEL0_SIZE;
 906                 ++bmap;
 907         }
 908 }
 909
 910 /*
 911  * The current Level 1 freemap has been exhausted, iterate to the next
 912  * one, return ENOSPC if no freemaps remain.
 913  *
 914  * At least two loops are required.  If we are not in relaxed mode and
 915  * we run out of storage we enter relaxed mode and do a third loop.
 916  * The relaxed mode is recorded back in the hmp so once we enter the mode
 917  * we remain relaxed until stuff begins to get freed and only do 2 loops.
 918  *
 919  * XXX this should rotate back to the beginning to handle freed-up space
 920  * XXX or use intermediate entries to locate free space. TODO
 921  */
 922 static int
 923 hammer2_freemap_iterate(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
 924                         hammer2_fiterate_t *iter)
 925 {
 926         hammer2_dev_t *hmp = (*parentp)->hmp;
 927
 928         iter->bnext &= ~HAMMER2_FREEMAP_LEVEL1_MASK;
 929         iter->bnext += HAMMER2_FREEMAP_LEVEL1_SIZE;
 930         if (iter->bnext >= hmp->voldata.volu_size) {
 931                 iter->bnext = 0;
 932                 if (++iter->loops >= 2) {
 933                         if (iter->relaxed == 0)
 934                                 iter->relaxed = 1;
 935                         else
 936                                 return (HAMMER2_ERROR_ENOSPC);
 937                 }
 938         }
 939         return(HAMMER2_ERROR_EAGAIN);
 940 }
 941
 942 /*
 943  * Adjust the bit-pattern for data in the freemap bitmap according to
 944  * (how).  This code is called from on-mount recovery to fixup (mark
 945  * as allocated) blocks whos freemap upates might not have been committed
 946  * in the last crash and is used by the bulk freemap scan to stage frees.
 947  *
 948  * WARNING! Cannot be called with a empty-data bref (radix == 0).
 949  *
 950  * XXX currently disabled when how == 0 (the normal real-time case).  At
 951  * the moment we depend on the bulk freescan to actually free blocks.  It
 952  * will still call this routine with a non-zero how to stage possible frees
 953  * and to do the actual free.
 954  */
 955 void
 956 hammer2_freemap_adjust(hammer2_dev_t *hmp, hammer2_blockref_t *bref,
 957                        int how)
 958 {
 959         hammer2_off_t data_off = bref->data_off;
 960         hammer2_chain_t *chain;
 961         hammer2_chain_t *parent;
 962         hammer2_bmap_data_t *bmap;
 963         hammer2_key_t key;
 964         hammer2_key_t key_dummy;
 965         hammer2_off_t l0size;
 966         hammer2_off_t l1size;
 967         hammer2_off_t l1mask;
 968         hammer2_tid_t mtid;
 969         hammer2_bitmap_t *bitmap;
 970         const hammer2_bitmap_t bmmask00 = 0;
 971         hammer2_bitmap_t bmmask01;
 972         hammer2_bitmap_t bmmask10;
 973         hammer2_bitmap_t bmmask11;
 974         size_t bytes;
 975         uint16_t class;
 976         int radix;
 977         int start;
 978         int count;
 979         int modified = 0;
 980         int error;
 981         size_t bgsize = 0;
 982
 983         KKASSERT(how == HAMMER2_FREEMAP_DORECOVER);
 984
 985         KKASSERT(hmp->spmp);
 986         mtid = hammer2_trans_sub(hmp->spmp);
 987
 988         radix = (int)data_off & HAMMER2_OFF_MASK_RADIX;
 989         KKASSERT(radix != 0);
 990         data_off &= ~HAMMER2_OFF_MASK_RADIX;
 991         KKASSERT(radix <= HAMMER2_RADIX_MAX);
 992
 993         if (radix)
 994                 bytes = (size_t)1 << radix;
 995         else
 996                 bytes = 0;
 997         class = (bref->type << 8) | HAMMER2_PBUFRADIX;
 998
 999         /*
1000          * We can't adjust the freemap for data allocations made by
1001          * newfs_hammer2.
1002          */
1003         if (data_off < hmp->voldata.allocator_beg)
1004                 return;
1005
1006         KKASSERT((data_off & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
1007
1008         /*
1009          * Lookup the level1 freemap chain.  The chain must exist.
1010          */
1011         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL1_RADIX);
1012         l0size = HAMMER2_FREEMAP_LEVEL0_SIZE;
1013         l1size = HAMMER2_FREEMAP_LEVEL1_SIZE;
1014         l1mask = l1size - 1;
1015
1016         parent = &hmp->fchain;
1017         hammer2_chain_ref(parent);
1018         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1019
1020         chain = hammer2_chain_lookup(&parent, &key_dummy, key, key + l1mask,
1021                                      &error,
1022                                      HAMMER2_LOOKUP_ALWAYS |
1023                                      HAMMER2_LOOKUP_MATCHIND);
1024
1025         /*
1026          * Stop early if we are trying to free something but no leaf exists.
1027          */
1028         if (chain == NULL && how != HAMMER2_FREEMAP_DORECOVER) {
1029                 kprintf("hammer2_freemap_adjust: %016jx: no chain\n",
1030                         (intmax_t)bref->data_off);
1031                 goto done;
1032         }
1033         if (chain->error) {
1034                 kprintf("hammer2_freemap_adjust: %016jx: error %s\n",
1035                         (intmax_t)bref->data_off,
1036                         hammer2_error_str(chain->error));
1037                 hammer2_chain_unlock(chain);
1038                 hammer2_chain_drop(chain);
1039                 chain = NULL;
1040                 goto done;
1041         }
1042
1043         /*
1044          * Create any missing leaf(s) if we are doing a recovery (marking
1045          * the block(s) as being allocated instead of being freed).  Be sure
1046          * to initialize the auxillary freemap tracking info in the
1047          * bref.check.freemap structure.
1048          */
1049         if (chain == NULL && how == HAMMER2_FREEMAP_DORECOVER) {
1050                 error = hammer2_chain_create(&parent, &chain, NULL, hmp->spmp,
1051                                      HAMMER2_METH_DEFAULT,
1052                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
1053                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
1054                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
1055                                      mtid, 0, 0);
1056
1057                 if (hammer2_debug & 0x0040) {
1058                         kprintf("fixup create chain %p %016jx:%d\n",
1059                                 chain, chain->bref.key, chain->bref.keybits);
1060                 }
1061
1062                 if (error == 0) {
1063                         error = hammer2_chain_modify(chain, mtid, 0, 0);
1064                         KKASSERT(error == 0);
1065                         bzero(&chain->data->bmdata[0],
1066                               HAMMER2_FREEMAP_LEVELN_PSIZE);
1067                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
1068                         chain->bref.check.freemap.avail = l1size;
1069                         /* bref.methods should already be inherited */
1070
1071                         hammer2_freemap_init(hmp, key, chain);
1072                 }
1073                 /* XXX handle error */
1074         }
1075
1076 #if FREEMAP_DEBUG
1077         kprintf("FREEMAP ADJUST TYPE %d %016jx/%d DATA_OFF=%016jx\n",
1078                 chain->bref.type, chain->bref.key,
1079                 chain->bref.keybits, chain->bref.data_off);
1080 #endif
1081
1082         /*
1083          * Calculate the bitmask (runs in 2-bit pairs).
1084          */
1085         start = ((int)(data_off >> HAMMER2_FREEMAP_BLOCK_RADIX) & 15) * 2;
1086         bmmask01 = (hammer2_bitmap_t)1 << start;
1087         bmmask10 = (hammer2_bitmap_t)2 << start;
1088         bmmask11 = (hammer2_bitmap_t)3 << start;
1089
1090         /*
1091          * Fixup the bitmap.  Partial blocks cannot be fully freed unless
1092          * a bulk scan is able to roll them up.
1093          */
1094         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
1095                 count = 1;
1096                 if (how == HAMMER2_FREEMAP_DOREALFREE)
1097                         how = HAMMER2_FREEMAP_DOMAYFREE;
1098         } else {
1099                 count = 1 << (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
1100         }
1101
1102         /*
1103          * [re]load the bmap and bitmap pointers.  Each bmap entry covers
1104          * a 4MB swath.  The bmap itself (LEVEL1) covers 2GB.
1105          *
1106          * Be sure to reset the linear iterator to ensure that the adjustment
1107          * is not ignored.
1108          */
1109 again:
1110         bmap = &chain->data->bmdata[(int)(data_off >> HAMMER2_SEGRADIX) &
1111                                     (HAMMER2_FREEMAP_COUNT - 1)];
1112         bitmap = &bmap->bitmapq[(int)(data_off >> (HAMMER2_SEGRADIX - 3)) & 7];
1113
1114         if (modified)
1115                 bmap->linear = 0;
1116
1117         while (count) {
1118                 KKASSERT(bmmask11);
1119                 if (how == HAMMER2_FREEMAP_DORECOVER) {
1120                         /*
1121                          * Recovery request, mark as allocated.
1122                          */
1123                         if ((*bitmap & bmmask11) != bmmask11) {
1124                                 if (modified == 0) {
1125                                         hammer2_chain_modify(chain, mtid, 0, 0);
1126                                         modified = 1;
1127                                         goto again;
1128                                 }
1129                                 if ((*bitmap & bmmask11) == bmmask00) {
1130                                         bmap->avail -=
1131                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1132                                         bgsize += HAMMER2_FREEMAP_BLOCK_SIZE;
1133                                 }
1134                                 if (bmap->class == 0)
1135                                         bmap->class = class;
1136                                 *bitmap |= bmmask11;
1137                                 if (hammer2_debug & 0x0040) {
1138                                         kprintf("hammer2_freemap_adjust: "
1139                                                 "fixup type=%02x "
1140                                                 "block=%016jx/%zd\n",
1141                                                 bref->type, data_off, bytes);
1142                                 }
1143                         } else {
1144                                 /*
1145                                 kprintf("hammer2_freemap_adjust:  good "
1146                                         "type=%02x block=%016jx/%zd\n",
1147                                         bref->type, data_off, bytes);
1148                                 */
1149                         }
1150                 }
1151 #if 0
1152                 /*
1153                  * XXX this stuff doesn't work, avail is miscalculated and
1154                  * code 10 means something else now.
1155                  */
1156                 else if ((*bitmap & bmmask11) == bmmask11) {
1157                         /*
1158                          * Mayfree/Realfree request and bitmap is currently
1159                          * marked as being fully allocated.
1160                          */
1161                         if (!modified) {
1162                                 hammer2_chain_modify(chain, 0);
1163                                 modified = 1;
1164                                 goto again;
1165                         }
1166                         if (how == HAMMER2_FREEMAP_DOREALFREE)
1167                                 *bitmap &= ~bmmask11;
1168                         else
1169                                 *bitmap = (*bitmap & ~bmmask11) | bmmask10;
1170                 } else if ((*bitmap & bmmask11) == bmmask10) {
1171                         /*
1172                          * Mayfree/Realfree request and bitmap is currently
1173                          * marked as being possibly freeable.
1174                          */
1175                         if (how == HAMMER2_FREEMAP_DOREALFREE) {
1176                                 if (!modified) {
1177                                         hammer2_chain_modify(chain, 0);
1178                                         modified = 1;
1179                                         goto again;
1180                                 }
1181                                 *bitmap &= ~bmmask11;
1182                         }
1183                 } else {
1184                         /*
1185                          * 01 - Not implemented, currently illegal state
1186                          * 00 - Not allocated at all, illegal free.
1187                          */
1188                         panic("hammer2_freemap_adjust: "
1189                               "Illegal state %08x(%08x)",
1190                               *bitmap, *bitmap & bmmask11);
1191                 }
1192 #endif
1193                 --count;
1194                 bmmask01 <<= 2;
1195                 bmmask10 <<= 2;
1196                 bmmask11 <<= 2;
1197         }
1198 #if HAMMER2_BMAP_ELEMENTS != 8
1199 #error "hammer2_freemap.c: HAMMER2_BMAP_ELEMENTS expected to be 8"
1200 #endif
1201         if (how == HAMMER2_FREEMAP_DOREALFREE && modified) {
1202                 bmap->avail += 1 << radix;
1203                 KKASSERT(bmap->avail <= HAMMER2_SEGSIZE);
1204                 if (bmap->avail == HAMMER2_SEGSIZE &&
1205                     bmap->bitmapq[0] == 0 &&
1206                     bmap->bitmapq[1] == 0 &&
1207                     bmap->bitmapq[2] == 0 &&
1208                     bmap->bitmapq[3] == 0 &&
1209                     bmap->bitmapq[4] == 0 &&
1210                     bmap->bitmapq[5] == 0 &&
1211                     bmap->bitmapq[6] == 0 &&
1212                     bmap->bitmapq[7] == 0) {
1213                         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL0_RADIX);
1214                         kprintf("Freeseg %016jx\n", (intmax_t)key);
1215                         bmap->class = 0;
1216                 }
1217         }
1218
1219         /*
1220          * chain->bref.check.freemap.bigmask (XXX)
1221          *
1222          * Setting bigmask is a hint to the allocation code that there might
1223          * be something allocatable.  We also set this in recovery... it
1224          * doesn't hurt and we might want to use the hint for other validation
1225          * operations later on.
1226          *
1227          * We could calculate the largest possible allocation and set the
1228          * radii that could fit, but its easier just to set bigmask to -1.
1229          */
1230         if (modified) {
1231                 chain->bref.check.freemap.bigmask = -1;
1232                 hmp->freemap_relaxed = 0;       /* reset heuristic */
1233         }
1234
1235         hammer2_chain_unlock(chain);
1236         hammer2_chain_drop(chain);
1237 done:
1238         hammer2_chain_unlock(parent);
1239         hammer2_chain_drop(parent);
1240
1241         if (bgsize) {
1242                 hammer2_voldata_lock(hmp);
1243                 hammer2_voldata_modify(hmp);
1244                 hmp->voldata.allocator_free -= bgsize;
1245                 hammer2_voldata_unlock(hmp);
1246         }
1247 }
1248
1249 /*
1250  * Validate the freemap, in three stages.
1251  *
1252  * stage-1      ALLOCATED     -> POSSIBLY FREE
1253  *              POSSIBLY FREE -> POSSIBLY FREE (type corrected)
1254  *
1255  *      This transitions bitmap entries from ALLOCATED to POSSIBLY FREE.
1256  *      The POSSIBLY FREE state does not mean that a block is actually free
1257  *      and may be transitioned back to ALLOCATED in stage-2.
1258  *
1259  *      This is typically done during normal filesystem operations when
1260  *      something is deleted or a block is replaced.
1261  *
1262  *      This is done by bulkfree in-bulk after a memory-bounded meta-data
1263  *      scan to try to determine what might be freeable.
1264  *
1265  *      This can be done unconditionally through a freemap scan when the
1266  *      intention is to brute-force recover the proper state of the freemap.
1267  *
1268  * stage-2      POSSIBLY FREE -> ALLOCATED      (scan metadata topology)
1269  *
1270  *      This is done by bulkfree during a meta-data scan to ensure that
1271  *      all blocks still actually allocated by the filesystem are marked
1272  *      as such.
1273  *
1274  *      NOTE! Live filesystem transitions to POSSIBLY FREE can occur while
1275  *            the bulkfree stage-2 and stage-3 is running.  The live filesystem
1276  *            will use the alternative POSSIBLY FREE type (2) to prevent
1277  *            stage-3 from improperly transitioning unvetted possibly-free
1278  *            blocks to FREE.
1279  *
1280  * stage-3      POSSIBLY FREE (type 1) -> FREE  (scan freemap)
1281  *
1282  *      This is done by bulkfree to finalize POSSIBLY FREE states.
1283  *
1284  */