sys/vfs/hammer2/hammer2_strategy.c

   1 /*
   2  * Copyright (c) 2011-2015 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  * by Daniel Flores (GSOC 2013 - mentored by Matthew Dillon, compression)
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  * 3. Neither the name of The DragonFly Project nor the names of its
  20  *    contributors may be used to endorse or promote products derived
  21  *    from this software without specific, prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  26  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  27  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  28  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  29  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  30  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  31  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36 /*
  37  * This module handles low level logical file I/O (strategy) which backs
  38  * the logical buffer cache.
  39  *
  40  * [De]compression, zero-block, check codes, and buffer cache operations
  41  * for file data is handled here.
  42  *
  43  * Live dedup makes its home here as well.
  44  */
  45
  46 #include <sys/param.h>
  47 #include <sys/systm.h>
  48 #include <sys/kernel.h>
  49 #include <sys/fcntl.h>
  50 #include <sys/buf.h>
  51 #include <sys/proc.h>
  52 #include <sys/namei.h>
  53 #include <sys/mount.h>
  54 #include <sys/vnode.h>
  55 #include <sys/mountctl.h>
  56 #include <sys/dirent.h>
  57 #include <sys/uio.h>
  58 #include <sys/objcache.h>
  59 #include <sys/event.h>
  60 #include <sys/file.h>
  61 #include <vfs/fifofs/fifo.h>
  62
  63 #include "hammer2.h"
  64 #include "hammer2_lz4.h"
  65
  66 #include "zlib/hammer2_zlib.h"
  67
  68 struct objcache *cache_buffer_read;
  69 struct objcache *cache_buffer_write;
  70
  71 /*
  72  * Strategy code (async logical file buffer I/O from system)
  73  *
  74  * WARNING: The strategy code cannot safely use hammer2 transactions
  75  *          as this can deadlock against vfs_sync's vfsync() call
  76  *          if multiple flushes are queued.  All H2 structures must
  77  *          already be present and ready for the DIO.
  78  *
  79  *          Reads can be initiated asynchronously, writes have to be
  80  *          spooled to a separate thread for action to avoid deadlocks.
  81  */
  82 static void hammer2_strategy_xop_read(hammer2_xop_t *arg, int clindex);
  83 static void hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex);
  84 static int hammer2_strategy_read(struct vop_strategy_args *ap);
  85 static int hammer2_strategy_write(struct vop_strategy_args *ap);
  86 static void hammer2_strategy_read_completion(hammer2_chain_t *chain,
  87                                 char *data, struct bio *bio);
  88
  89 static void hammer2_dedup_record(hammer2_chain_t *chain, char *data);
  90 static hammer2_off_t hammer2_dedup_lookup(hammer2_dev_t *hmp,
  91                         char **datap, int pblksize);
  92
  93 int
  94 hammer2_vop_strategy(struct vop_strategy_args *ap)
  95 {
  96         struct bio *biop;
  97         struct buf *bp;
  98         int error;
  99
 100         biop = ap->a_bio;
 101         bp = biop->bio_buf;
 102
 103         switch(bp->b_cmd) {
 104         case BUF_CMD_READ:
 105                 error = hammer2_strategy_read(ap);
 106                 ++hammer2_iod_file_read;
 107                 break;
 108         case BUF_CMD_WRITE:
 109                 error = hammer2_strategy_write(ap);
 110                 ++hammer2_iod_file_write;
 111                 break;
 112         default:
 113                 bp->b_error = error = EINVAL;
 114                 bp->b_flags |= B_ERROR;
 115                 biodone(biop);
 116                 break;
 117         }
 118         return (error);
 119 }
 120
 121 /*
 122  * Return the largest contiguous physical disk range for the logical
 123  * request, in bytes.
 124  *
 125  * (struct vnode *vp, off_t loffset, off_t *doffsetp, int *runp, int *runb)
 126  *
 127  * Basically disabled, the logical buffer write thread has to deal with
 128  * buffers one-at-a-time.
 129  */
 130 int
 131 hammer2_vop_bmap(struct vop_bmap_args *ap)
 132 {
 133         *ap->a_doffsetp = NOOFFSET;
 134         if (ap->a_runp)
 135                 *ap->a_runp = 0;
 136         if (ap->a_runb)
 137                 *ap->a_runb = 0;
 138         return (EOPNOTSUPP);
 139 }
 140
 141 /****************************************************************************
 142  *                              READ SUPPORT                                *
 143  ****************************************************************************/
 144 /*
 145  * Callback used in read path in case that a block is compressed with LZ4.
 146  */
 147 static
 148 void
 149 hammer2_decompress_LZ4_callback(const char *data, u_int bytes, struct bio *bio)
 150 {
 151         struct buf *bp;
 152         char *compressed_buffer;
 153         int compressed_size;
 154         int result;
 155
 156         bp = bio->bio_buf;
 157
 158 #if 0
 159         if bio->bio_caller_info2.index &&
 160               bio->bio_caller_info1.uvalue32 !=
 161               crc32(bp->b_data, bp->b_bufsize) --- return error
 162 #endif
 163
 164         KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
 165         compressed_size = *(const int *)data;
 166         KKASSERT(compressed_size <= bytes - sizeof(int));
 167
 168         compressed_buffer = objcache_get(cache_buffer_read, M_INTWAIT);
 169         result = LZ4_decompress_safe(__DECONST(char *, &data[sizeof(int)]),
 170                                      compressed_buffer,
 171                                      compressed_size,
 172                                      bp->b_bufsize);
 173         if (result < 0) {
 174                 kprintf("READ PATH: Error during decompression."
 175                         "bio %016jx/%d\n",
 176                         (intmax_t)bio->bio_offset, bytes);
 177                 /* make sure it isn't random garbage */
 178                 bzero(compressed_buffer, bp->b_bufsize);
 179         }
 180         KKASSERT(result <= bp->b_bufsize);
 181         bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
 182         if (result < bp->b_bufsize)
 183                 bzero(bp->b_data + result, bp->b_bufsize - result);
 184         objcache_put(cache_buffer_read, compressed_buffer);
 185         bp->b_resid = 0;
 186         bp->b_flags |= B_AGE;
 187 }
 188
 189 /*
 190  * Callback used in read path in case that a block is compressed with ZLIB.
 191  * It is almost identical to LZ4 callback, so in theory they can be unified,
 192  * but we didn't want to make changes in bio structure for that.
 193  */
 194 static
 195 void
 196 hammer2_decompress_ZLIB_callback(const char *data, u_int bytes, struct bio *bio)
 197 {
 198         struct buf *bp;
 199         char *compressed_buffer;
 200         z_stream strm_decompress;
 201         int result;
 202         int ret;
 203
 204         bp = bio->bio_buf;
 205
 206         KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
 207         strm_decompress.avail_in = 0;
 208         strm_decompress.next_in = Z_NULL;
 209
 210         ret = inflateInit(&strm_decompress);
 211
 212         if (ret != Z_OK)
 213                 kprintf("HAMMER2 ZLIB: Fatal error in inflateInit.\n");
 214
 215         compressed_buffer = objcache_get(cache_buffer_read, M_INTWAIT);
 216         strm_decompress.next_in = __DECONST(char *, data);
 217
 218         /* XXX supply proper size, subset of device bp */
 219         strm_decompress.avail_in = bytes;
 220         strm_decompress.next_out = compressed_buffer;
 221         strm_decompress.avail_out = bp->b_bufsize;
 222
 223         ret = inflate(&strm_decompress, Z_FINISH);
 224         if (ret != Z_STREAM_END) {
 225                 kprintf("HAMMER2 ZLIB: Fatar error during decompression.\n");
 226                 bzero(compressed_buffer, bp->b_bufsize);
 227         }
 228         bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
 229         result = bp->b_bufsize - strm_decompress.avail_out;
 230         if (result < bp->b_bufsize)
 231                 bzero(bp->b_data + result, strm_decompress.avail_out);
 232         objcache_put(cache_buffer_read, compressed_buffer);
 233         ret = inflateEnd(&strm_decompress);
 234
 235         bp->b_resid = 0;
 236         bp->b_flags |= B_AGE;
 237 }
 238
 239 /*
 240  * Logical buffer I/O, async read.
 241  */
 242 static
 243 int
 244 hammer2_strategy_read(struct vop_strategy_args *ap)
 245 {
 246         hammer2_xop_strategy_t *xop;
 247         struct buf *bp;
 248         struct bio *bio;
 249         struct bio *nbio;
 250         hammer2_inode_t *ip;
 251         hammer2_key_t lbase;
 252
 253         bio = ap->a_bio;
 254         bp = bio->bio_buf;
 255         ip = VTOI(ap->a_vp);
 256         nbio = push_bio(bio);
 257
 258         lbase = bio->bio_offset;
 259         KKASSERT(((int)lbase & HAMMER2_PBUFMASK) == 0);
 260
 261         xop = hammer2_xop_alloc(ip, 0);
 262         xop->finished = 0;
 263         xop->bio = bio;
 264         xop->lbase = lbase;
 265         hammer2_mtx_init(&xop->lock, "h2bio");
 266         hammer2_xop_start(&xop->head, hammer2_strategy_xop_read);
 267         /* asynchronous completion */
 268
 269         return(0);
 270 }
 271
 272 /*
 273  * Per-node XOP (threaded), do a synchronous lookup of the chain and
 274  * its data.  The frontend is asynchronous, so we are also responsible
 275  * for racing to terminate the frontend.
 276  */
 277 static
 278 void
 279 hammer2_strategy_xop_read(hammer2_xop_t *arg, int clindex)
 280 {
 281         hammer2_xop_strategy_t *xop = &arg->xop_strategy;
 282         hammer2_chain_t *parent;
 283         hammer2_chain_t *chain;
 284         hammer2_key_t key_dummy;
 285         hammer2_key_t lbase;
 286         struct bio *bio;
 287         struct buf *bp;
 288         int cache_index = -1;
 289         int error;
 290
 291         lbase = xop->lbase;
 292         bio = xop->bio;
 293         bp = bio->bio_buf;
 294
 295         parent = hammer2_inode_chain(xop->head.ip1, clindex,
 296                                      HAMMER2_RESOLVE_ALWAYS |
 297                                      HAMMER2_RESOLVE_SHARED);
 298         if (parent) {
 299                 chain = hammer2_chain_lookup(&parent, &key_dummy,
 300                                              lbase, lbase,
 301                                              &cache_index,
 302                                              HAMMER2_LOOKUP_ALWAYS |
 303                                              HAMMER2_LOOKUP_SHARED);
 304                 error = chain ? chain->error : 0;
 305         } else {
 306                 error = EIO;
 307                 chain = NULL;
 308         }
 309         error = hammer2_xop_feed(&xop->head, chain, clindex, error);
 310         if (chain)
 311                 hammer2_chain_drop(chain);
 312         if (parent) {
 313                 hammer2_chain_unlock(parent);
 314                 hammer2_chain_drop(parent);
 315         }
 316         chain = NULL;   /* safety */
 317         parent = NULL;  /* safety */
 318
 319         /*
 320          * Race to finish the frontend
 321          */
 322         if (xop->finished)
 323                 return;
 324         hammer2_mtx_ex(&xop->lock);
 325         if (xop->finished) {
 326                 hammer2_mtx_unlock(&xop->lock);
 327                 return;
 328         }
 329
 330         /*
 331          * Async operation has not completed and we now own the lock.
 332          * Determine if we can complete the operation by issuing the
 333          * frontend collection non-blocking.
 334          */
 335         error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
 336
 337         switch(error) {
 338         case 0:
 339                 xop->finished = 1;
 340                 hammer2_mtx_unlock(&xop->lock);
 341                 chain = xop->head.cluster.focus;
 342                 hammer2_strategy_read_completion(chain, (char *)chain->data,
 343                                                  xop->bio);
 344                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 345                 biodone(bio);
 346                 break;
 347         case ENOENT:
 348                 xop->finished = 1;
 349                 hammer2_mtx_unlock(&xop->lock);
 350                 bp->b_resid = 0;
 351                 bp->b_error = 0;
 352                 bzero(bp->b_data, bp->b_bcount);
 353                 biodone(bio);
 354                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 355                 break;
 356         case EINPROGRESS:
 357                 hammer2_mtx_unlock(&xop->lock);
 358                 break;
 359         default:
 360                 xop->finished = 1;
 361                 hammer2_mtx_unlock(&xop->lock);
 362                 bp->b_flags |= B_ERROR;
 363                 bp->b_error = EIO;
 364                 biodone(bio);
 365                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 366                 break;
 367         }
 368 }
 369
 370 static
 371 void
 372 hammer2_strategy_read_completion(hammer2_chain_t *chain, char *data,
 373                                  struct bio *bio)
 374 {
 375         struct buf *bp = bio->bio_buf;
 376
 377         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 378                 /*
 379                  * Data is embedded in the inode (copy from inode).
 380                  */
 381                 bcopy(((hammer2_inode_data_t *)data)->u.data,
 382                       bp->b_data, HAMMER2_EMBEDDED_BYTES);
 383                 bzero(bp->b_data + HAMMER2_EMBEDDED_BYTES,
 384                       bp->b_bcount - HAMMER2_EMBEDDED_BYTES);
 385                 bp->b_resid = 0;
 386                 bp->b_error = 0;
 387         } else if (chain->bref.type == HAMMER2_BREF_TYPE_DATA) {
 388                 /*
 389                  * Data is on-media, record for live dedup.
 390                  */
 391                 hammer2_dedup_record(chain, data);
 392
 393                 /*
 394                  * Decopmression and copy.
 395                  */
 396                 switch (HAMMER2_DEC_COMP(chain->bref.methods)) {
 397                 case HAMMER2_COMP_LZ4:
 398                         hammer2_decompress_LZ4_callback(data, chain->bytes,
 399                                                         bio);
 400                         break;
 401                 case HAMMER2_COMP_ZLIB:
 402                         hammer2_decompress_ZLIB_callback(data, chain->bytes,
 403                                                          bio);
 404                         break;
 405                 case HAMMER2_COMP_NONE:
 406                         KKASSERT(chain->bytes <= bp->b_bcount);
 407                         bcopy(data, bp->b_data, chain->bytes);
 408                         if (chain->bytes < bp->b_bcount) {
 409                                 bzero(bp->b_data + chain->bytes,
 410                                       bp->b_bcount - chain->bytes);
 411                         }
 412                         bp->b_flags |= B_NOTMETA;
 413                         bp->b_resid = 0;
 414                         bp->b_error = 0;
 415                         break;
 416                 default:
 417                         panic("hammer2_strategy_read: "
 418                               "unknown compression type");
 419                 }
 420         } else {
 421                 panic("hammer2_strategy_read: unknown bref type");
 422         }
 423 }
 424
 425 /****************************************************************************
 426  *                              WRITE SUPPORT                               *
 427  ****************************************************************************/
 428
 429 /*
 430  * Functions for compression in threads,
 431  * from hammer2_vnops.c
 432  */
 433 static void hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
 434                                 hammer2_chain_t **parentp,
 435                                 hammer2_key_t lbase, int ioflag, int pblksize,
 436                                 hammer2_tid_t mtid, int *errorp);
 437 static void hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
 438                                 hammer2_chain_t **parentp,
 439                                 hammer2_key_t lbase, int ioflag, int pblksize,
 440                                 hammer2_tid_t mtid, int *errorp,
 441                                 int comp_algo, int check_algo);
 442 static void hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
 443                                 hammer2_chain_t **parentp,
 444                                 hammer2_key_t lbase, int ioflag, int pblksize,
 445                                 hammer2_tid_t mtid, int *errorp,
 446                                 int check_algo);
 447 static int test_block_zeros(const char *buf, size_t bytes);
 448 static void zero_write(struct buf *bp, hammer2_inode_t *ip,
 449                                 hammer2_chain_t **parentp,
 450                                 hammer2_key_t lbase,
 451                                 hammer2_tid_t mtid, int *errorp);
 452 static void hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp,
 453                                 int ioflag, int pblksize,
 454                                 hammer2_tid_t mtid, int *errorp,
 455                                 int check_algo);
 456
 457 static
 458 int
 459 hammer2_strategy_write(struct vop_strategy_args *ap)
 460 {
 461         hammer2_xop_strategy_t *xop;
 462         hammer2_pfs_t *pmp;
 463         struct bio *bio;
 464         struct buf *bp;
 465         hammer2_inode_t *ip;
 466
 467         bio = ap->a_bio;
 468         bp = bio->bio_buf;
 469         ip = VTOI(ap->a_vp);
 470         pmp = ip->pmp;
 471
 472         hammer2_lwinprog_ref(pmp);
 473         hammer2_trans_assert_strategy(pmp);
 474
 475         xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING);
 476         xop->finished = 0;
 477         xop->bio = bio;
 478         xop->lbase = bio->bio_offset;
 479         hammer2_xop_start(&xop->head, hammer2_strategy_xop_write);
 480         /* asynchronous completion */
 481
 482         hammer2_lwinprog_wait(pmp, hammer2_flush_pipe);
 483
 484         return(0);
 485 }
 486
 487 /*
 488  * Per-node XOP (threaded).  Write the logical buffer to the media.
 489  */
 490 static
 491 void
 492 hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex)
 493 {
 494         hammer2_xop_strategy_t *xop = &arg->xop_strategy;
 495         hammer2_chain_t *parent;
 496         hammer2_key_t lbase;
 497         hammer2_inode_t *ip;
 498         struct bio *bio;
 499         struct buf *bp;
 500         int error;
 501         int lblksize;
 502         int pblksize;
 503
 504         lbase = xop->lbase;
 505         bio = xop->bio;
 506         bp = bio->bio_buf;
 507         ip = xop->head.ip1;
 508
 509         /* hammer2_trans_init(parent->hmp->spmp, HAMMER2_TRANS_BUFCACHE); */
 510
 511         lblksize = hammer2_calc_logical(ip, bio->bio_offset, &lbase, NULL);
 512         pblksize = hammer2_calc_physical(ip, lbase);
 513         parent = hammer2_inode_chain(ip, clindex, HAMMER2_RESOLVE_ALWAYS);
 514         hammer2_write_file_core(bp, ip, &parent,
 515                                 lbase, IO_ASYNC, pblksize,
 516                                 xop->head.mtid, &error);
 517         if (parent) {
 518                 hammer2_chain_unlock(parent);
 519                 hammer2_chain_drop(parent);
 520                 parent = NULL;  /* safety */
 521         }
 522         error = hammer2_xop_feed(&xop->head, NULL, clindex, error);
 523
 524         /*
 525          * Race to finish the frontend
 526          */
 527         if (xop->finished)
 528                 return;
 529         hammer2_mtx_ex(&xop->lock);
 530         if (xop->finished) {
 531                 hammer2_mtx_unlock(&xop->lock);
 532                 return;
 533         }
 534
 535         /*
 536          * Async operation has not completed and we now own the lock.
 537          * Determine if we can complete the operation by issuing the
 538          * frontend collection non-blocking.
 539          */
 540         error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
 541
 542         switch(error) {
 543         case ENOENT:
 544         case 0:
 545                 xop->finished = 1;
 546                 hammer2_mtx_unlock(&xop->lock);
 547                 bp->b_resid = 0;
 548                 bp->b_error = 0;
 549                 biodone(bio);
 550                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 551                 hammer2_lwinprog_drop(ip->pmp);
 552                 break;
 553         case EINPROGRESS:
 554                 hammer2_mtx_unlock(&xop->lock);
 555                 break;
 556         default:
 557                 xop->finished = 1;
 558                 hammer2_mtx_unlock(&xop->lock);
 559                 bp->b_flags |= B_ERROR;
 560                 bp->b_error = EIO;
 561                 biodone(bio);
 562                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 563                 hammer2_lwinprog_drop(ip->pmp);
 564                 break;
 565         }
 566 }
 567
 568 /*
 569  * Wait for pending I/O to complete
 570  */
 571 void
 572 hammer2_bioq_sync(hammer2_pfs_t *pmp)
 573 {
 574         hammer2_lwinprog_wait(pmp, 0);
 575 }
 576
 577 /*
 578  * Create a new cluster at (cparent, lbase) and assign physical storage,
 579  * returning a cluster suitable for I/O.  The cluster will be in a modified
 580  * state.
 581  *
 582  * cparent can wind up being anything.
 583  *
 584  * If datap is not NULL, *datap points to the real data we intend to write.
 585  * If we can dedup the storage location we set *datap to NULL to indicate
 586  * to the caller that a dedup occurred.
 587  *
 588  * NOTE: Special case for data embedded in inode.
 589  */
 590 static
 591 hammer2_chain_t *
 592 hammer2_assign_physical(hammer2_inode_t *ip, hammer2_chain_t **parentp,
 593                         hammer2_key_t lbase, int pblksize,
 594                         hammer2_tid_t mtid, char **datap, int *errorp)
 595 {
 596         hammer2_chain_t *chain;
 597         hammer2_key_t key_dummy;
 598         hammer2_off_t dedup_off;
 599         int pradix = hammer2_getradix(pblksize);
 600         int cache_index = -1;
 601
 602         /*
 603          * Locate the chain associated with lbase, return a locked chain.
 604          * However, do not instantiate any data reference (which utilizes a
 605          * device buffer) because we will be using direct IO via the
 606          * logical buffer cache buffer.
 607          */
 608         *errorp = 0;
 609         KKASSERT(pblksize >= HAMMER2_ALLOC_MIN);
 610 retry:
 611         chain = hammer2_chain_lookup(parentp, &key_dummy,
 612                                      lbase, lbase,
 613                                      &cache_index,
 614                                      HAMMER2_LOOKUP_NODATA);
 615         if (chain == NULL) {
 616                 /*
 617                  * We found a hole, create a new chain entry.
 618                  *
 619                  * NOTE: DATA chains are created without device backing
 620                  *       store (nor do we want any).
 621                  */
 622                 dedup_off = hammer2_dedup_lookup((*parentp)->hmp, datap,
 623                                                  pblksize);
 624                 *errorp = hammer2_chain_create(parentp, &chain, ip->pmp,
 625                                                lbase, HAMMER2_PBUFRADIX,
 626                                                HAMMER2_BREF_TYPE_DATA,
 627                                                pblksize, mtid,
 628                                                dedup_off, 0);
 629                 if (chain == NULL) {
 630                         panic("hammer2_chain_create: par=%p error=%d\n",
 631                               *parentp, *errorp);
 632                         goto retry;
 633                 }
 634                 /*ip->delta_dcount += pblksize;*/
 635         } else {
 636                 switch (chain->bref.type) {
 637                 case HAMMER2_BREF_TYPE_INODE:
 638                         /*
 639                          * The data is embedded in the inode, which requires
 640                          * a bit more finess.
 641                          */
 642                         hammer2_chain_modify_ip(ip, chain, mtid, 0);
 643                         break;
 644                 case HAMMER2_BREF_TYPE_DATA:
 645                         dedup_off = hammer2_dedup_lookup(chain->hmp, datap,
 646                                                          pblksize);
 647                         if (chain->bytes != pblksize) {
 648                                 hammer2_chain_resize(ip, *parentp, chain,
 649                                                      mtid, dedup_off,
 650                                                      pradix,
 651                                                      HAMMER2_MODIFY_OPTDATA);
 652                         }
 653
 654                         /*
 655                          * DATA buffers must be marked modified whether the
 656                          * data is in a logical buffer or not.  We also have
 657                          * to make this call to fixup the chain data pointers
 658                          * after resizing in case this is an encrypted or
 659                          * compressed buffer.
 660                          */
 661                         hammer2_chain_modify(chain, mtid, dedup_off,
 662                                              HAMMER2_MODIFY_OPTDATA);
 663                         break;
 664                 default:
 665                         panic("hammer2_assign_physical: bad type");
 666                         /* NOT REACHED */
 667                         break;
 668                 }
 669         }
 670         return (chain);
 671 }
 672
 673 /*
 674  * hammer2_write_file_core() - hammer2_write_thread() helper
 675  *
 676  * The core write function which determines which path to take
 677  * depending on compression settings.  We also have to locate the
 678  * related chains so we can calculate and set the check data for
 679  * the blockref.
 680  */
 681 static
 682 void
 683 hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
 684                         hammer2_chain_t **parentp,
 685                         hammer2_key_t lbase, int ioflag, int pblksize,
 686                         hammer2_tid_t mtid, int *errorp)
 687 {
 688         hammer2_chain_t *chain;
 689         char *data = bp->b_data;
 690
 691         switch(HAMMER2_DEC_ALGO(ip->meta.comp_algo)) {
 692         case HAMMER2_COMP_NONE:
 693                 /*
 694                  * We have to assign physical storage to the buffer
 695                  * we intend to dirty or write now to avoid deadlocks
 696                  * in the strategy code later.
 697                  *
 698                  * This can return NOOFFSET for inode-embedded data.
 699                  * The strategy code will take care of it in that case.
 700                  */
 701                 chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
 702                                                 mtid, &data, errorp);
 703                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 704                         hammer2_inode_data_t *wipdata;
 705
 706                         wipdata = &chain->data->ipdata;
 707                         KKASSERT(wipdata->meta.op_flags &
 708                                  HAMMER2_OPFLAG_DIRECTDATA);
 709                         KKASSERT(bp->b_loffset == 0);
 710                         bcopy(bp->b_data, wipdata->u.data,
 711                               HAMMER2_EMBEDDED_BYTES);
 712                         ++hammer2_iod_file_wembed;
 713                 } else if (data == NULL) {
 714                         /*
 715                          * Copy of data already present on-media.
 716                          */
 717                         chain->bref.methods =
 718                                 HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
 719                                 HAMMER2_ENC_CHECK(ip->meta.check_algo);
 720                         hammer2_chain_setcheck(chain, bp->b_data);
 721                 } else {
 722                         hammer2_write_bp(chain, bp, ioflag, pblksize,
 723                                          mtid, errorp, ip->meta.check_algo);
 724                 }
 725                 if (chain) {
 726                         hammer2_chain_unlock(chain);
 727                         hammer2_chain_drop(chain);
 728                 }
 729                 break;
 730         case HAMMER2_COMP_AUTOZERO:
 731                 /*
 732                  * Check for zero-fill only
 733                  */
 734                 hammer2_zero_check_and_write(bp, ip, parentp,
 735                                              lbase, ioflag, pblksize,
 736                                              mtid, errorp,
 737                                              ip->meta.check_algo);
 738                 break;
 739         case HAMMER2_COMP_LZ4:
 740         case HAMMER2_COMP_ZLIB:
 741         default:
 742                 /*
 743                  * Check for zero-fill and attempt compression.
 744                  */
 745                 hammer2_compress_and_write(bp, ip, parentp,
 746                                            lbase, ioflag, pblksize,
 747                                            mtid, errorp,
 748                                            ip->meta.comp_algo,
 749                                            ip->meta.check_algo);
 750                 break;
 751         }
 752 }
 753
 754 /*
 755  * Helper
 756  *
 757  * Generic function that will perform the compression in compression
 758  * write path. The compression algorithm is determined by the settings
 759  * obtained from inode.
 760  */
 761 static
 762 void
 763 hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
 764         hammer2_chain_t **parentp,
 765         hammer2_key_t lbase, int ioflag, int pblksize,
 766         hammer2_tid_t mtid, int *errorp, int comp_algo, int check_algo)
 767 {
 768         hammer2_chain_t *chain;
 769         int comp_size;
 770         int comp_block_size;
 771         char *comp_buffer;
 772         char *data;
 773
 774         if (test_block_zeros(bp->b_data, pblksize)) {
 775                 zero_write(bp, ip, parentp, lbase, mtid, errorp);
 776                 return;
 777         }
 778
 779         comp_size = 0;
 780         comp_buffer = NULL;
 781
 782         KKASSERT(pblksize / 2 <= 32768);
 783
 784         if (ip->comp_heuristic < 8 || (ip->comp_heuristic & 7) == 0) {
 785                 z_stream strm_compress;
 786                 int comp_level;
 787                 int ret;
 788
 789                 switch(HAMMER2_DEC_ALGO(comp_algo)) {
 790                 case HAMMER2_COMP_LZ4:
 791                         comp_buffer = objcache_get(cache_buffer_write,
 792                                                    M_INTWAIT);
 793                         comp_size = LZ4_compress_limitedOutput(
 794                                         bp->b_data,
 795                                         &comp_buffer[sizeof(int)],
 796                                         pblksize,
 797                                         pblksize / 2 - sizeof(int));
 798                         /*
 799                          * We need to prefix with the size, LZ4
 800                          * doesn't do it for us.  Add the related
 801                          * overhead.
 802                          */
 803                         *(int *)comp_buffer = comp_size;
 804                         if (comp_size)
 805                                 comp_size += sizeof(int);
 806                         break;
 807                 case HAMMER2_COMP_ZLIB:
 808                         comp_level = HAMMER2_DEC_LEVEL(comp_algo);
 809                         if (comp_level == 0)
 810                                 comp_level = 6; /* default zlib compression */
 811                         else if (comp_level < 6)
 812                                 comp_level = 6;
 813                         else if (comp_level > 9)
 814                                 comp_level = 9;
 815                         ret = deflateInit(&strm_compress, comp_level);
 816                         if (ret != Z_OK) {
 817                                 kprintf("HAMMER2 ZLIB: fatal error "
 818                                         "on deflateInit.\n");
 819                         }
 820
 821                         comp_buffer = objcache_get(cache_buffer_write,
 822                                                    M_INTWAIT);
 823                         strm_compress.next_in = bp->b_data;
 824                         strm_compress.avail_in = pblksize;
 825                         strm_compress.next_out = comp_buffer;
 826                         strm_compress.avail_out = pblksize / 2;
 827                         ret = deflate(&strm_compress, Z_FINISH);
 828                         if (ret == Z_STREAM_END) {
 829                                 comp_size = pblksize / 2 -
 830                                             strm_compress.avail_out;
 831                         } else {
 832                                 comp_size = 0;
 833                         }
 834                         ret = deflateEnd(&strm_compress);
 835                         break;
 836                 default:
 837                         kprintf("Error: Unknown compression method.\n");
 838                         kprintf("Comp_method = %d.\n", comp_algo);
 839                         break;
 840                 }
 841         }
 842
 843         if (comp_size == 0) {
 844                 /*
 845                  * compression failed or turned off
 846                  */
 847                 comp_block_size = pblksize;     /* safety */
 848                 if (++ip->comp_heuristic > 128)
 849                         ip->comp_heuristic = 8;
 850         } else {
 851                 /*
 852                  * compression succeeded
 853                  */
 854                 ip->comp_heuristic = 0;
 855                 if (comp_size <= 1024) {
 856                         comp_block_size = 1024;
 857                 } else if (comp_size <= 2048) {
 858                         comp_block_size = 2048;
 859                 } else if (comp_size <= 4096) {
 860                         comp_block_size = 4096;
 861                 } else if (comp_size <= 8192) {
 862                         comp_block_size = 8192;
 863                 } else if (comp_size <= 16384) {
 864                         comp_block_size = 16384;
 865                 } else if (comp_size <= 32768) {
 866                         comp_block_size = 32768;
 867                 } else {
 868                         panic("hammer2: WRITE PATH: "
 869                               "Weird comp_size value.");
 870                         /* NOT REACHED */
 871                         comp_block_size = pblksize;
 872                 }
 873
 874                 /*
 875                  * Must zero the remainder or dedup (which operates on a
 876                  * physical block basis) will not find matches.
 877                  */
 878                 if (comp_size < comp_block_size) {
 879                         bzero(comp_buffer + comp_size,
 880                               comp_block_size - comp_size);
 881                 }
 882         }
 883
 884         /*
 885          * Assign physical storage, data will be set to NULL if a live-dedup
 886          * was successful.
 887          */
 888         data = comp_size ? comp_buffer : bp->b_data;
 889         chain = hammer2_assign_physical(ip, parentp, lbase, comp_block_size,
 890                                         mtid, &data, errorp);
 891
 892         if (*errorp) {
 893                 kprintf("WRITE PATH: An error occurred while "
 894                         "assigning physical space.\n");
 895                 KKASSERT(chain == NULL);
 896                 goto done;
 897         }
 898
 899         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 900                 hammer2_inode_data_t *wipdata;
 901
 902                 hammer2_chain_modify_ip(ip, chain, mtid, 0);
 903                 wipdata = &chain->data->ipdata;
 904                 KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
 905                 KKASSERT(bp->b_loffset == 0);
 906                 bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
 907                 ++hammer2_iod_file_wembed;
 908         } else if (data == NULL) {
 909                 /*
 910                  * Live deduplication, a copy of the data is already present
 911                  * on the media.
 912                  */
 913                 char *bdata;
 914
 915                 if (comp_size) {
 916                         chain->bref.methods =
 917                                 HAMMER2_ENC_COMP(comp_algo) +
 918                                 HAMMER2_ENC_CHECK(check_algo);
 919                 } else {
 920                         chain->bref.methods =
 921                                 HAMMER2_ENC_COMP(
 922                                         HAMMER2_COMP_NONE) +
 923                                 HAMMER2_ENC_CHECK(check_algo);
 924                 }
 925                 bdata = comp_size ? comp_buffer : bp->b_data;
 926                 hammer2_chain_setcheck(chain, bdata);
 927                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
 928         } else {
 929                 hammer2_io_t *dio;
 930                 char *bdata;
 931
 932                 KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
 933
 934                 switch(chain->bref.type) {
 935                 case HAMMER2_BREF_TYPE_INODE:
 936                         panic("hammer2_write_bp: unexpected inode\n");
 937                         break;
 938                 case HAMMER2_BREF_TYPE_DATA:
 939                         /*
 940                          * Optimize out the read-before-write
 941                          * if possible.
 942                          */
 943                         *errorp = hammer2_io_newnz(chain->hmp,
 944                                                    chain->bref.data_off,
 945                                                    chain->bytes,
 946                                                    &dio);
 947                         if (*errorp) {
 948                                 hammer2_io_brelse(&dio);
 949                                 kprintf("hammer2: WRITE PATH: "
 950                                         "dbp bread error\n");
 951                                 break;
 952                         }
 953                         bdata = hammer2_io_data(dio, chain->bref.data_off);
 954
 955                         /*
 956                          * When loading the block make sure we don't
 957                          * leave garbage after the compressed data.
 958                          */
 959                         if (comp_size) {
 960                                 chain->bref.methods =
 961                                         HAMMER2_ENC_COMP(comp_algo) +
 962                                         HAMMER2_ENC_CHECK(check_algo);
 963                                 bcopy(comp_buffer, bdata, comp_size);
 964                         } else {
 965                                 chain->bref.methods =
 966                                         HAMMER2_ENC_COMP(
 967                                                 HAMMER2_COMP_NONE) +
 968                                         HAMMER2_ENC_CHECK(check_algo);
 969                                 bcopy(bp->b_data, bdata, pblksize);
 970                         }
 971
 972                         /*
 973                          * The flush code doesn't calculate check codes for
 974                          * file data (doing so can result in excessive I/O),
 975                          * so we do it here.
 976                          */
 977                         hammer2_chain_setcheck(chain, bdata);
 978                         hammer2_dedup_record(chain, bdata);
 979
 980                         /*
 981                          * Device buffer is now valid, chain is no longer in
 982                          * the initial state.
 983                          *
 984                          * (No blockref table worries with file data)
 985                          */
 986                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
 987
 988                         /* Now write the related bdp. */
 989                         if (ioflag & IO_SYNC) {
 990                                 /*
 991                                  * Synchronous I/O requested.
 992                                  */
 993                                 hammer2_io_bwrite(&dio);
 994                         /*
 995                         } else if ((ioflag & IO_DIRECT) &&
 996                                    loff + n == pblksize) {
 997                                 hammer2_io_bdwrite(&dio);
 998                         */
 999                         } else if (ioflag & IO_ASYNC) {
1000                                 hammer2_io_bawrite(&dio);
1001                         } else {
1002                                 hammer2_io_bdwrite(&dio);
1003                         }
1004                         break;
1005                 default:
1006                         panic("hammer2_write_bp: bad chain type %d\n",
1007                                 chain->bref.type);
1008                         /* NOT REACHED */
1009                         break;
1010                 }
1011         }
1012 done:
1013         if (chain) {
1014                 hammer2_chain_unlock(chain);
1015                 hammer2_chain_drop(chain);
1016         }
1017         if (comp_buffer)
1018                 objcache_put(cache_buffer_write, comp_buffer);
1019 }
1020
1021 /*
1022  * Helper
1023  *
1024  * Function that performs zero-checking and writing without compression,
1025  * it corresponds to default zero-checking path.
1026  */
1027 static
1028 void
1029 hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
1030         hammer2_chain_t **parentp,
1031         hammer2_key_t lbase, int ioflag, int pblksize,
1032         hammer2_tid_t mtid, int *errorp,
1033         int check_algo)
1034 {
1035         hammer2_chain_t *chain;
1036         char *data = bp->b_data;
1037
1038         if (test_block_zeros(bp->b_data, pblksize)) {
1039                 zero_write(bp, ip, parentp, lbase, mtid, errorp);
1040         } else {
1041                 chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
1042                                                 mtid, &data, errorp);
1043                 if (data) {
1044                         hammer2_write_bp(chain, bp, ioflag, pblksize,
1045                                          mtid, errorp, check_algo);
1046                 } /* else dedup occurred */
1047                 if (chain) {
1048                         hammer2_chain_unlock(chain);
1049                         hammer2_chain_drop(chain);
1050                 }
1051         }
1052 }
1053
1054 /*
1055  * Helper
1056  *
1057  * A function to test whether a block of data contains only zeros,
1058  * returns TRUE (non-zero) if the block is all zeros.
1059  */
1060 static
1061 int
1062 test_block_zeros(const char *buf, size_t bytes)
1063 {
1064         size_t i;
1065
1066         for (i = 0; i < bytes; i += sizeof(long)) {
1067                 if (*(const long *)(buf + i) != 0)
1068                         return (0);
1069         }
1070         return (1);
1071 }
1072
1073 /*
1074  * Helper
1075  *
1076  * Function to "write" a block that contains only zeros.
1077  */
1078 static
1079 void
1080 zero_write(struct buf *bp, hammer2_inode_t *ip,
1081            hammer2_chain_t **parentp,
1082            hammer2_key_t lbase, hammer2_tid_t mtid, int *errorp __unused)
1083 {
1084         hammer2_chain_t *chain;
1085         hammer2_key_t key_dummy;
1086         int cache_index = -1;
1087
1088         chain = hammer2_chain_lookup(parentp, &key_dummy,
1089                                      lbase, lbase,
1090                                      &cache_index,
1091                                      HAMMER2_LOOKUP_NODATA);
1092         if (chain) {
1093                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1094                         hammer2_inode_data_t *wipdata;
1095
1096                         hammer2_chain_modify_ip(ip, chain, mtid, 0);
1097                         wipdata = &chain->data->ipdata;
1098                         KKASSERT(wipdata->meta.op_flags &
1099                                  HAMMER2_OPFLAG_DIRECTDATA);
1100                         KKASSERT(bp->b_loffset == 0);
1101                         bzero(wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1102                         ++hammer2_iod_file_wembed;
1103                 } else {
1104                         hammer2_chain_delete(*parentp, chain,
1105                                              mtid, HAMMER2_DELETE_PERMANENT);
1106                         ++hammer2_iod_file_wzero;
1107                 }
1108                 hammer2_chain_unlock(chain);
1109                 hammer2_chain_drop(chain);
1110         } else {
1111                 ++hammer2_iod_file_wzero;
1112         }
1113 }
1114
1115 /*
1116  * Helper
1117  *
1118  * Function to write the data as it is, without performing any sort of
1119  * compression. This function is used in path without compression and
1120  * default zero-checking path.
1121  */
1122 static
1123 void
1124 hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp, int ioflag,
1125                  int pblksize,
1126                  hammer2_tid_t mtid, int *errorp, int check_algo)
1127 {
1128         hammer2_inode_data_t *wipdata;
1129         hammer2_io_t *dio;
1130         char *bdata;
1131         int error;
1132
1133         error = 0;      /* XXX TODO below */
1134
1135         KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1136
1137         switch(chain->bref.type) {
1138         case HAMMER2_BREF_TYPE_INODE:
1139                 wipdata = &chain->data->ipdata;
1140                 KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
1141                 KKASSERT(bp->b_loffset == 0);
1142                 bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1143                 error = 0;
1144                 ++hammer2_iod_file_wembed;
1145                 break;
1146         case HAMMER2_BREF_TYPE_DATA:
1147                 error = hammer2_io_newnz(chain->hmp,
1148                                          chain->bref.data_off,
1149                                          chain->bytes, &dio);
1150                 if (error) {
1151                         hammer2_io_bqrelse(&dio);
1152                         kprintf("hammer2: WRITE PATH: "
1153                                 "dbp bread error\n");
1154                         break;
1155                 }
1156                 bdata = hammer2_io_data(dio, chain->bref.data_off);
1157
1158                 chain->bref.methods = HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
1159                                       HAMMER2_ENC_CHECK(check_algo);
1160                 bcopy(bp->b_data, bdata, chain->bytes);
1161
1162                 /*
1163                  * The flush code doesn't calculate check codes for
1164                  * file data (doing so can result in excessive I/O),
1165                  * so we do it here.
1166                  */
1167                 hammer2_chain_setcheck(chain, bdata);
1168                 hammer2_dedup_record(chain, bdata);
1169
1170                 /*
1171                  * Device buffer is now valid, chain is no longer in
1172                  * the initial state.
1173                  *
1174                  * (No blockref table worries with file data)
1175                  */
1176                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1177
1178                 if (ioflag & IO_SYNC) {
1179                         /*
1180                          * Synchronous I/O requested.
1181                          */
1182                         hammer2_io_bwrite(&dio);
1183                 /*
1184                 } else if ((ioflag & IO_DIRECT) &&
1185                            loff + n == pblksize) {
1186                         hammer2_io_bdwrite(&dio);
1187                 */
1188                 } else if (ioflag & IO_ASYNC) {
1189                         hammer2_io_bawrite(&dio);
1190                 } else {
1191                         hammer2_io_bdwrite(&dio);
1192                 }
1193                 break;
1194         default:
1195                 panic("hammer2_write_bp: bad chain type %d\n",
1196                       chain->bref.type);
1197                 /* NOT REACHED */
1198                 error = 0;
1199                 break;
1200         }
1201         KKASSERT(error == 0);   /* XXX TODO */
1202         *errorp = error;
1203 }
1204
1205 /*
1206  * LIVE DEDUP HEURISTIC
1207  *
1208  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1209  *          All fields must be loaded into locals and validated.
1210  */
1211 static
1212 void
1213 hammer2_dedup_record(hammer2_chain_t *chain, char *data)
1214 {
1215         hammer2_dev_t *hmp;
1216         hammer2_dedup_t *dedup;
1217         int32_t crc;
1218         int best = 0;
1219         int i;
1220         int dticks;
1221
1222         hmp = chain->hmp;
1223         crc = hammer2_icrc32(data, chain->bytes);
1224         dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1225         for (i = 0; i < 4; ++i) {
1226                 if (dedup[i].data_crc == crc) {
1227                         best = i;
1228                         break;
1229                 }
1230                 dticks = (int)(dedup[i].ticks - dedup[best].ticks);
1231                 if (dticks < 0 || dticks > hz * 60 * 30)
1232                         best = i;
1233         }
1234         dedup += best;
1235         if (hammer2_debug & 0x40000) {
1236                 kprintf("REC %04x %08x %016jx\n",
1237                         (int)(dedup - hmp->heur_dedup),
1238                         crc,
1239                         chain->bref.data_off);
1240         }
1241         dedup->ticks = ticks;
1242         dedup->data_off = chain->bref.data_off;
1243         dedup->data_crc = crc;
1244         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DEDUP);
1245 }
1246
1247 static
1248 hammer2_off_t
1249 hammer2_dedup_lookup(hammer2_dev_t *hmp, char **datap, int pblksize)
1250 {
1251         hammer2_dedup_t *dedup;
1252         hammer2_io_t *dio;
1253         hammer2_off_t off;
1254         uint32_t crc;
1255         char *data;
1256         int i;
1257
1258         data = *datap;
1259         if (data == NULL)
1260                 return 0;
1261
1262         crc = hammer2_icrc32(data, pblksize);
1263         dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1264
1265         if (hammer2_debug & 0x40000) {
1266                 kprintf("LOC %04x/4 %08x\n",
1267                         (int)(dedup - hmp->heur_dedup),
1268                         crc);
1269         }
1270
1271         for (i = 0; i < 4; ++i) {
1272                 off = dedup[i].data_off;
1273                 cpu_ccfence();
1274                 if (dedup[i].data_crc != crc)
1275                         continue;
1276                 if ((1 << (int)(off & HAMMER2_OFF_MASK_RADIX)) != pblksize)
1277                         continue;
1278                 dio = hammer2_io_getquick(hmp, off, pblksize);
1279                 if (dio &&
1280                     bcmp(data, hammer2_io_data(dio, off), pblksize) == 0) {
1281                         if (hammer2_debug & 0x40000) {
1282                                 kprintf("DEDUP SUCCESS %016jx\n",
1283                                         (intmax_t)off);
1284                         }
1285                         hammer2_io_putblk(&dio);
1286                         *datap = NULL;
1287                         dedup[i].ticks = ticks; /* update use */
1288                         ++hammer2_iod_file_wdedup;
1289                         return off;             /* RETURN */
1290                 }
1291                 if (dio)
1292                         hammer2_io_putblk(&dio);
1293         }
1294         return 0;
1295 }
1296
1297 /*
1298  * Poof.  Races are ok, if someone gets in and reuses a dedup offset
1299  * before or while we are clearing it they will also recover the freemap
1300  * entry (set it to fully allocated), so a bulkfree race can only set it
1301  * to a possibly-free state.
1302  *
1303  * XXX ok, well, not really sure races are ok but going to run with it
1304  *     for the moment.
1305  */
1306 void
1307 hammer2_dedup_clear(hammer2_dev_t *hmp)
1308 {
1309         int i;
1310
1311         for (i = 0; i < HAMMER2_DEDUP_HEUR_SIZE; ++i) {
1312                 hmp->heur_dedup[i].data_off = 0;
1313                 hmp->heur_dedup[i].ticks = ticks - 1;
1314         }
1315 }