sys/vfs/hammer2/hammer2_freemap.c

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