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_unlock(chain);
 312                 hammer2_chain_drop(chain);
 313         }
 314         if (parent) {
 315                 hammer2_chain_unlock(parent);
 316                 hammer2_chain_drop(parent);
 317         }
 318         chain = NULL;   /* safety */
 319         parent = NULL;  /* safety */
 320
 321         /*
 322          * Race to finish the frontend
 323          */
 324         if (xop->finished)
 325                 return;
 326         hammer2_mtx_ex(&xop->lock);
 327         if (xop->finished) {
 328                 hammer2_mtx_unlock(&xop->lock);
 329                 return;
 330         }
 331
 332         /*
 333          * Async operation has not completed and we now own the lock.
 334          * Determine if we can complete the operation by issuing the
 335          * frontend collection non-blocking.
 336          */
 337         error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
 338
 339         switch(error) {
 340         case 0:
 341                 xop->finished = 1;
 342                 hammer2_mtx_unlock(&xop->lock);
 343                 chain = xop->head.cluster.focus;
 344                 hammer2_strategy_read_completion(chain, (char *)chain->data,
 345                                                  xop->bio);
 346                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 347                 biodone(bio);
 348                 break;
 349         case ENOENT:
 350                 xop->finished = 1;
 351                 hammer2_mtx_unlock(&xop->lock);
 352                 bp->b_resid = 0;
 353                 bp->b_error = 0;
 354                 bzero(bp->b_data, bp->b_bcount);
 355                 biodone(bio);
 356                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 357                 break;
 358         case EINPROGRESS:
 359                 hammer2_mtx_unlock(&xop->lock);
 360                 break;
 361         default:
 362                 xop->finished = 1;
 363                 hammer2_mtx_unlock(&xop->lock);
 364                 bp->b_flags |= B_ERROR;
 365                 bp->b_error = EIO;
 366                 biodone(bio);
 367                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 368                 break;
 369         }
 370 }
 371
 372 static
 373 void
 374 hammer2_strategy_read_completion(hammer2_chain_t *chain, char *data,
 375                                  struct bio *bio)
 376 {
 377         struct buf *bp = bio->bio_buf;
 378
 379         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 380                 /*
 381                  * Data is embedded in the inode (copy from inode).
 382                  */
 383                 bcopy(((hammer2_inode_data_t *)data)->u.data,
 384                       bp->b_data, HAMMER2_EMBEDDED_BYTES);
 385                 bzero(bp->b_data + HAMMER2_EMBEDDED_BYTES,
 386                       bp->b_bcount - HAMMER2_EMBEDDED_BYTES);
 387                 bp->b_resid = 0;
 388                 bp->b_error = 0;
 389         } else if (chain->bref.type == HAMMER2_BREF_TYPE_DATA) {
 390                 /*
 391                  * Data is on-media, record for live dedup.
 392                  */
 393                 hammer2_dedup_record(chain, data);
 394
 395                 /*
 396                  * Decopmression and copy.
 397                  */
 398                 switch (HAMMER2_DEC_COMP(chain->bref.methods)) {
 399                 case HAMMER2_COMP_LZ4:
 400                         hammer2_decompress_LZ4_callback(data, chain->bytes,
 401                                                         bio);
 402                         break;
 403                 case HAMMER2_COMP_ZLIB:
 404                         hammer2_decompress_ZLIB_callback(data, chain->bytes,
 405                                                          bio);
 406                         break;
 407                 case HAMMER2_COMP_NONE:
 408                         KKASSERT(chain->bytes <= bp->b_bcount);
 409                         bcopy(data, bp->b_data, chain->bytes);
 410                         if (chain->bytes < bp->b_bcount) {
 411                                 bzero(bp->b_data + chain->bytes,
 412                                       bp->b_bcount - chain->bytes);
 413                         }
 414                         bp->b_flags |= B_NOTMETA;
 415                         bp->b_resid = 0;
 416                         bp->b_error = 0;
 417                         break;
 418                 default:
 419                         panic("hammer2_strategy_read: "
 420                               "unknown compression type");
 421                 }
 422         } else {
 423                 panic("hammer2_strategy_read: unknown bref type");
 424         }
 425 }
 426
 427 /****************************************************************************
 428  *                              WRITE SUPPORT                               *
 429  ****************************************************************************/
 430
 431 /*
 432  * Functions for compression in threads,
 433  * from hammer2_vnops.c
 434  */
 435 static void hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
 436                                 hammer2_chain_t **parentp,
 437                                 hammer2_key_t lbase, int ioflag, int pblksize,
 438                                 hammer2_tid_t mtid, int *errorp);
 439 static void hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
 440                                 hammer2_chain_t **parentp,
 441                                 hammer2_key_t lbase, int ioflag, int pblksize,
 442                                 hammer2_tid_t mtid, int *errorp,
 443                                 int comp_algo, int check_algo);
 444 static void hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
 445                                 hammer2_chain_t **parentp,
 446                                 hammer2_key_t lbase, int ioflag, int pblksize,
 447                                 hammer2_tid_t mtid, int *errorp,
 448                                 int check_algo);
 449 static int test_block_zeros(const char *buf, size_t bytes);
 450 static void zero_write(struct buf *bp, hammer2_inode_t *ip,
 451                                 hammer2_chain_t **parentp,
 452                                 hammer2_key_t lbase,
 453                                 hammer2_tid_t mtid, int *errorp);
 454 static void hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp,
 455                                 int ioflag, int pblksize,
 456                                 hammer2_tid_t mtid, int *errorp,
 457                                 int check_algo);
 458
 459 static
 460 int
 461 hammer2_strategy_write(struct vop_strategy_args *ap)
 462 {
 463         hammer2_xop_strategy_t *xop;
 464         hammer2_pfs_t *pmp;
 465         struct bio *bio;
 466         struct buf *bp;
 467         hammer2_inode_t *ip;
 468
 469         bio = ap->a_bio;
 470         bp = bio->bio_buf;
 471         ip = VTOI(ap->a_vp);
 472         pmp = ip->pmp;
 473
 474         hammer2_lwinprog_ref(pmp);
 475         hammer2_trans_assert_strategy(pmp);
 476
 477         xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING);
 478         xop->finished = 0;
 479         xop->bio = bio;
 480         xop->lbase = bio->bio_offset;
 481         hammer2_xop_start(&xop->head, hammer2_strategy_xop_write);
 482         /* asynchronous completion */
 483
 484         hammer2_lwinprog_wait(pmp, hammer2_flush_pipe);
 485
 486         return(0);
 487 }
 488
 489 /*
 490  * Per-node XOP (threaded).  Write the logical buffer to the media.
 491  */
 492 static
 493 void
 494 hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex)
 495 {
 496         hammer2_xop_strategy_t *xop = &arg->xop_strategy;
 497         hammer2_chain_t *parent;
 498         hammer2_key_t lbase;
 499         hammer2_inode_t *ip;
 500         struct bio *bio;
 501         struct buf *bp;
 502         int error;
 503         int lblksize;
 504         int pblksize;
 505
 506         lbase = xop->lbase;
 507         bio = xop->bio;
 508         bp = bio->bio_buf;
 509         ip = xop->head.ip1;
 510
 511         /* hammer2_trans_init(parent->hmp->spmp, HAMMER2_TRANS_BUFCACHE); */
 512
 513         lblksize = hammer2_calc_logical(ip, bio->bio_offset, &lbase, NULL);
 514         pblksize = hammer2_calc_physical(ip, lbase);
 515         parent = hammer2_inode_chain(ip, clindex, HAMMER2_RESOLVE_ALWAYS);
 516         hammer2_write_file_core(bp, ip, &parent,
 517                                 lbase, IO_ASYNC, pblksize,
 518                                 xop->head.mtid, &error);
 519         if (parent) {
 520                 hammer2_chain_unlock(parent);
 521                 hammer2_chain_drop(parent);
 522                 parent = NULL;  /* safety */
 523         }
 524         error = hammer2_xop_feed(&xop->head, NULL, clindex, error);
 525
 526         /*
 527          * Race to finish the frontend
 528          */
 529         if (xop->finished)
 530                 return;
 531         hammer2_mtx_ex(&xop->lock);
 532         if (xop->finished) {
 533                 hammer2_mtx_unlock(&xop->lock);
 534                 return;
 535         }
 536
 537         /*
 538          * Async operation has not completed and we now own the lock.
 539          * Determine if we can complete the operation by issuing the
 540          * frontend collection non-blocking.
 541          */
 542         error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
 543
 544         switch(error) {
 545         case ENOENT:
 546         case 0:
 547                 xop->finished = 1;
 548                 hammer2_mtx_unlock(&xop->lock);
 549                 bp->b_resid = 0;
 550                 bp->b_error = 0;
 551                 biodone(bio);
 552                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 553                 hammer2_lwinprog_drop(ip->pmp);
 554                 break;
 555         case EINPROGRESS:
 556                 hammer2_mtx_unlock(&xop->lock);
 557                 break;
 558         default:
 559                 xop->finished = 1;
 560                 hammer2_mtx_unlock(&xop->lock);
 561                 bp->b_flags |= B_ERROR;
 562                 bp->b_error = EIO;
 563                 biodone(bio);
 564                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 565                 hammer2_lwinprog_drop(ip->pmp);
 566                 break;
 567         }
 568 }
 569
 570 /*
 571  * Wait for pending I/O to complete
 572  */
 573 void
 574 hammer2_bioq_sync(hammer2_pfs_t *pmp)
 575 {
 576         hammer2_lwinprog_wait(pmp, 0);
 577 }
 578
 579 /*
 580  * Create a new cluster at (cparent, lbase) and assign physical storage,
 581  * returning a cluster suitable for I/O.  The cluster will be in a modified
 582  * state.
 583  *
 584  * cparent can wind up being anything.
 585  *
 586  * If datap is not NULL, *datap points to the real data we intend to write.
 587  * If we can dedup the storage location we set *datap to NULL to indicate
 588  * to the caller that a dedup occurred.
 589  *
 590  * NOTE: Special case for data embedded in inode.
 591  */
 592 static
 593 hammer2_chain_t *
 594 hammer2_assign_physical(hammer2_inode_t *ip, hammer2_chain_t **parentp,
 595                         hammer2_key_t lbase, int pblksize,
 596                         hammer2_tid_t mtid, char **datap, int *errorp)
 597 {
 598         hammer2_chain_t *chain;
 599         hammer2_key_t key_dummy;
 600         hammer2_off_t dedup_off;
 601         int pradix = hammer2_getradix(pblksize);
 602         int cache_index = -1;
 603
 604         /*
 605          * Locate the chain associated with lbase, return a locked chain.
 606          * However, do not instantiate any data reference (which utilizes a
 607          * device buffer) because we will be using direct IO via the
 608          * logical buffer cache buffer.
 609          */
 610         *errorp = 0;
 611         KKASSERT(pblksize >= HAMMER2_ALLOC_MIN);
 612 retry:
 613         chain = hammer2_chain_lookup(parentp, &key_dummy,
 614                                      lbase, lbase,
 615                                      &cache_index,
 616                                      HAMMER2_LOOKUP_NODATA);
 617         if (chain == NULL) {
 618                 /*
 619                  * We found a hole, create a new chain entry.
 620                  *
 621                  * NOTE: DATA chains are created without device backing
 622                  *       store (nor do we want any).
 623                  */
 624                 dedup_off = hammer2_dedup_lookup((*parentp)->hmp, datap,
 625                                                  pblksize);
 626                 *errorp = hammer2_chain_create(parentp, &chain, ip->pmp,
 627                                                lbase, HAMMER2_PBUFRADIX,
 628                                                HAMMER2_BREF_TYPE_DATA,
 629                                                pblksize, mtid,
 630                                                dedup_off, 0);
 631                 if (chain == NULL) {
 632                         panic("hammer2_chain_create: par=%p error=%d\n",
 633                               *parentp, *errorp);
 634                         goto retry;
 635                 }
 636                 /*ip->delta_dcount += pblksize;*/
 637         } else {
 638                 switch (chain->bref.type) {
 639                 case HAMMER2_BREF_TYPE_INODE:
 640                         /*
 641                          * The data is embedded in the inode, which requires
 642                          * a bit more finess.
 643                          */
 644                         hammer2_chain_modify_ip(ip, chain, mtid, 0);
 645                         break;
 646                 case HAMMER2_BREF_TYPE_DATA:
 647                         dedup_off = hammer2_dedup_lookup(chain->hmp, datap,
 648                                                          pblksize);
 649                         if (chain->bytes != pblksize) {
 650                                 hammer2_chain_resize(ip, *parentp, chain,
 651                                                      mtid, dedup_off,
 652                                                      pradix,
 653                                                      HAMMER2_MODIFY_OPTDATA);
 654                         }
 655
 656                         /*
 657                          * DATA buffers must be marked modified whether the
 658                          * data is in a logical buffer or not.  We also have
 659                          * to make this call to fixup the chain data pointers
 660                          * after resizing in case this is an encrypted or
 661                          * compressed buffer.
 662                          */
 663                         hammer2_chain_modify(chain, mtid, dedup_off,
 664                                              HAMMER2_MODIFY_OPTDATA);
 665                         break;
 666                 default:
 667                         panic("hammer2_assign_physical: bad type");
 668                         /* NOT REACHED */
 669                         break;
 670                 }
 671         }
 672         return (chain);
 673 }
 674
 675 /*
 676  * hammer2_write_file_core() - hammer2_write_thread() helper
 677  *
 678  * The core write function which determines which path to take
 679  * depending on compression settings.  We also have to locate the
 680  * related chains so we can calculate and set the check data for
 681  * the blockref.
 682  */
 683 static
 684 void
 685 hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
 686                         hammer2_chain_t **parentp,
 687                         hammer2_key_t lbase, int ioflag, int pblksize,
 688                         hammer2_tid_t mtid, int *errorp)
 689 {
 690         hammer2_chain_t *chain;
 691         char *data = bp->b_data;
 692
 693         switch(HAMMER2_DEC_ALGO(ip->meta.comp_algo)) {
 694         case HAMMER2_COMP_NONE:
 695                 /*
 696                  * We have to assign physical storage to the buffer
 697                  * we intend to dirty or write now to avoid deadlocks
 698                  * in the strategy code later.
 699                  *
 700                  * This can return NOOFFSET for inode-embedded data.
 701                  * The strategy code will take care of it in that case.
 702                  */
 703                 chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
 704                                                 mtid, &data, errorp);
 705                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 706                         hammer2_inode_data_t *wipdata;
 707
 708                         wipdata = &chain->data->ipdata;
 709                         KKASSERT(wipdata->meta.op_flags &
 710                                  HAMMER2_OPFLAG_DIRECTDATA);
 711                         KKASSERT(bp->b_loffset == 0);
 712                         bcopy(bp->b_data, wipdata->u.data,
 713                               HAMMER2_EMBEDDED_BYTES);
 714                         ++hammer2_iod_file_wembed;
 715                 } else if (data == NULL) {
 716                         /*
 717                          * Copy of data already present on-media.
 718                          */
 719                         chain->bref.methods =
 720                                 HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
 721                                 HAMMER2_ENC_CHECK(ip->meta.check_algo);
 722                         hammer2_chain_setcheck(chain, bp->b_data);
 723                 } else {
 724                         hammer2_write_bp(chain, bp, ioflag, pblksize,
 725                                          mtid, errorp, ip->meta.check_algo);
 726                 }
 727                 if (chain) {
 728                         hammer2_chain_unlock(chain);
 729                         hammer2_chain_drop(chain);
 730                 }
 731                 break;
 732         case HAMMER2_COMP_AUTOZERO:
 733                 /*
 734                  * Check for zero-fill only
 735                  */
 736                 hammer2_zero_check_and_write(bp, ip, parentp,
 737                                              lbase, ioflag, pblksize,
 738                                              mtid, errorp,
 739                                              ip->meta.check_algo);
 740                 break;
 741         case HAMMER2_COMP_LZ4:
 742         case HAMMER2_COMP_ZLIB:
 743         default:
 744                 /*
 745                  * Check for zero-fill and attempt compression.
 746                  */
 747                 hammer2_compress_and_write(bp, ip, parentp,
 748                                            lbase, ioflag, pblksize,
 749                                            mtid, errorp,
 750                                            ip->meta.comp_algo,
 751                                            ip->meta.check_algo);
 752                 break;
 753         }
 754 }
 755
 756 /*
 757  * Helper
 758  *
 759  * Generic function that will perform the compression in compression
 760  * write path. The compression algorithm is determined by the settings
 761  * obtained from inode.
 762  */
 763 static
 764 void
 765 hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
 766         hammer2_chain_t **parentp,
 767         hammer2_key_t lbase, int ioflag, int pblksize,
 768         hammer2_tid_t mtid, int *errorp, int comp_algo, int check_algo)
 769 {
 770         hammer2_chain_t *chain;
 771         int comp_size;
 772         int comp_block_size;
 773         char *comp_buffer;
 774         char *data;
 775
 776         if (test_block_zeros(bp->b_data, pblksize)) {
 777                 zero_write(bp, ip, parentp, lbase, mtid, errorp);
 778                 return;
 779         }
 780
 781         comp_size = 0;
 782         comp_buffer = NULL;
 783
 784         KKASSERT(pblksize / 2 <= 32768);
 785
 786         if (ip->comp_heuristic < 8 || (ip->comp_heuristic & 7) == 0) {
 787                 z_stream strm_compress;
 788                 int comp_level;
 789                 int ret;
 790
 791                 switch(HAMMER2_DEC_ALGO(comp_algo)) {
 792                 case HAMMER2_COMP_LZ4:
 793                         comp_buffer = objcache_get(cache_buffer_write,
 794                                                    M_INTWAIT);
 795                         comp_size = LZ4_compress_limitedOutput(
 796                                         bp->b_data,
 797                                         &comp_buffer[sizeof(int)],
 798                                         pblksize,
 799                                         pblksize / 2 - sizeof(int));
 800                         /*
 801                          * We need to prefix with the size, LZ4
 802                          * doesn't do it for us.  Add the related
 803                          * overhead.
 804                          */
 805                         *(int *)comp_buffer = comp_size;
 806                         if (comp_size)
 807                                 comp_size += sizeof(int);
 808                         break;
 809                 case HAMMER2_COMP_ZLIB:
 810                         comp_level = HAMMER2_DEC_LEVEL(comp_algo);
 811                         if (comp_level == 0)
 812                                 comp_level = 6; /* default zlib compression */
 813                         else if (comp_level < 6)
 814                                 comp_level = 6;
 815                         else if (comp_level > 9)
 816                                 comp_level = 9;
 817                         ret = deflateInit(&strm_compress, comp_level);
 818                         if (ret != Z_OK) {
 819                                 kprintf("HAMMER2 ZLIB: fatal error "
 820                                         "on deflateInit.\n");
 821                         }
 822
 823                         comp_buffer = objcache_get(cache_buffer_write,
 824                                                    M_INTWAIT);
 825                         strm_compress.next_in = bp->b_data;
 826                         strm_compress.avail_in = pblksize;
 827                         strm_compress.next_out = comp_buffer;
 828                         strm_compress.avail_out = pblksize / 2;
 829                         ret = deflate(&strm_compress, Z_FINISH);
 830                         if (ret == Z_STREAM_END) {
 831                                 comp_size = pblksize / 2 -
 832                                             strm_compress.avail_out;
 833                         } else {
 834                                 comp_size = 0;
 835                         }
 836                         ret = deflateEnd(&strm_compress);
 837                         break;
 838                 default:
 839                         kprintf("Error: Unknown compression method.\n");
 840                         kprintf("Comp_method = %d.\n", comp_algo);
 841                         break;
 842                 }
 843         }
 844
 845         if (comp_size == 0) {
 846                 /*
 847                  * compression failed or turned off
 848                  */
 849                 comp_block_size = pblksize;     /* safety */
 850                 if (++ip->comp_heuristic > 128)
 851                         ip->comp_heuristic = 8;
 852         } else {
 853                 /*
 854                  * compression succeeded
 855                  */
 856                 ip->comp_heuristic = 0;
 857                 if (comp_size <= 1024) {
 858                         comp_block_size = 1024;
 859                 } else if (comp_size <= 2048) {
 860                         comp_block_size = 2048;
 861                 } else if (comp_size <= 4096) {
 862                         comp_block_size = 4096;
 863                 } else if (comp_size <= 8192) {
 864                         comp_block_size = 8192;
 865                 } else if (comp_size <= 16384) {
 866                         comp_block_size = 16384;
 867                 } else if (comp_size <= 32768) {
 868                         comp_block_size = 32768;
 869                 } else {
 870                         panic("hammer2: WRITE PATH: "
 871                               "Weird comp_size value.");
 872                         /* NOT REACHED */
 873                         comp_block_size = pblksize;
 874                 }
 875
 876                 /*
 877                  * Must zero the remainder or dedup (which operates on a
 878                  * physical block basis) will not find matches.
 879                  */
 880                 if (comp_size < comp_block_size) {
 881                         bzero(comp_buffer + comp_size,
 882                               comp_block_size - comp_size);
 883                 }
 884         }
 885
 886         /*
 887          * Assign physical storage, data will be set to NULL if a live-dedup
 888          * was successful.
 889          */
 890         data = comp_size ? comp_buffer : bp->b_data;
 891         chain = hammer2_assign_physical(ip, parentp, lbase, comp_block_size,
 892                                         mtid, &data, errorp);
 893
 894         if (*errorp) {
 895                 kprintf("WRITE PATH: An error occurred while "
 896                         "assigning physical space.\n");
 897                 KKASSERT(chain == NULL);
 898                 goto done;
 899         }
 900
 901         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 902                 hammer2_inode_data_t *wipdata;
 903
 904                 hammer2_chain_modify_ip(ip, chain, mtid, 0);
 905                 wipdata = &chain->data->ipdata;
 906                 KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
 907                 KKASSERT(bp->b_loffset == 0);
 908                 bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
 909                 ++hammer2_iod_file_wembed;
 910         } else if (data == NULL) {
 911                 /*
 912                  * Live deduplication, a copy of the data is already present
 913                  * on the media.
 914                  */
 915                 char *bdata;
 916
 917                 if (comp_size) {
 918                         chain->bref.methods =
 919                                 HAMMER2_ENC_COMP(comp_algo) +
 920                                 HAMMER2_ENC_CHECK(check_algo);
 921                 } else {
 922                         chain->bref.methods =
 923                                 HAMMER2_ENC_COMP(
 924                                         HAMMER2_COMP_NONE) +
 925                                 HAMMER2_ENC_CHECK(check_algo);
 926                 }
 927                 bdata = comp_size ? comp_buffer : bp->b_data;
 928                 hammer2_chain_setcheck(chain, bdata);
 929                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
 930         } else {
 931                 hammer2_io_t *dio;
 932                 char *bdata;
 933
 934                 KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
 935
 936                 switch(chain->bref.type) {
 937                 case HAMMER2_BREF_TYPE_INODE:
 938                         panic("hammer2_write_bp: unexpected inode\n");
 939                         break;
 940                 case HAMMER2_BREF_TYPE_DATA:
 941                         /*
 942                          * Optimize out the read-before-write
 943                          * if possible.
 944                          */
 945                         *errorp = hammer2_io_newnz(chain->hmp,
 946                                                    chain->bref.data_off,
 947                                                    chain->bytes,
 948                                                    &dio);
 949                         if (*errorp) {
 950                                 hammer2_io_brelse(&dio);
 951                                 kprintf("hammer2: WRITE PATH: "
 952                                         "dbp bread error\n");
 953                                 break;
 954                         }
 955                         bdata = hammer2_io_data(dio, chain->bref.data_off);
 956
 957                         /*
 958                          * When loading the block make sure we don't
 959                          * leave garbage after the compressed data.
 960                          */
 961                         if (comp_size) {
 962                                 chain->bref.methods =
 963                                         HAMMER2_ENC_COMP(comp_algo) +
 964                                         HAMMER2_ENC_CHECK(check_algo);
 965                                 bcopy(comp_buffer, bdata, comp_size);
 966                         } else {
 967                                 chain->bref.methods =
 968                                         HAMMER2_ENC_COMP(
 969                                                 HAMMER2_COMP_NONE) +
 970                                         HAMMER2_ENC_CHECK(check_algo);
 971                                 bcopy(bp->b_data, bdata, pblksize);
 972                         }
 973
 974                         /*
 975                          * The flush code doesn't calculate check codes for
 976                          * file data (doing so can result in excessive I/O),
 977                          * so we do it here.
 978                          *
 979                          * Record for dedup only after the DIO's buffer cache
 980                          * buffer has been updated.
 981                          */
 982                         hammer2_chain_setcheck(chain, bdata);
 983                         hammer2_dedup_record(chain, bdata);
 984
 985                         /*
 986                          * Device buffer is now valid, chain is no longer in
 987                          * the initial state.
 988                          *
 989                          * (No blockref table worries with file data)
 990                          */
 991                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
 992
 993                         /* Now write the related bdp. */
 994                         if (ioflag & IO_SYNC) {
 995                                 /*
 996                                  * Synchronous I/O requested.
 997                                  */
 998                                 hammer2_io_bwrite(&dio);
 999                         /*
1000                         } else if ((ioflag & IO_DIRECT) &&
1001                                    loff + n == pblksize) {
1002                                 hammer2_io_bdwrite(&dio);
1003                         */
1004                         } else if (ioflag & IO_ASYNC) {
1005                                 hammer2_io_bawrite(&dio);
1006                         } else {
1007                                 hammer2_io_bdwrite(&dio);
1008                         }
1009                         break;
1010                 default:
1011                         panic("hammer2_write_bp: bad chain type %d\n",
1012                                 chain->bref.type);
1013                         /* NOT REACHED */
1014                         break;
1015                 }
1016         }
1017 done:
1018         if (chain) {
1019                 hammer2_chain_unlock(chain);
1020                 hammer2_chain_drop(chain);
1021         }
1022         if (comp_buffer)
1023                 objcache_put(cache_buffer_write, comp_buffer);
1024 }
1025
1026 /*
1027  * Helper
1028  *
1029  * Function that performs zero-checking and writing without compression,
1030  * it corresponds to default zero-checking path.
1031  */
1032 static
1033 void
1034 hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
1035         hammer2_chain_t **parentp,
1036         hammer2_key_t lbase, int ioflag, int pblksize,
1037         hammer2_tid_t mtid, int *errorp,
1038         int check_algo)
1039 {
1040         hammer2_chain_t *chain;
1041         char *data = bp->b_data;
1042
1043         if (test_block_zeros(bp->b_data, pblksize)) {
1044                 zero_write(bp, ip, parentp, lbase, mtid, errorp);
1045         } else {
1046                 chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
1047                                                 mtid, &data, errorp);
1048                 if (data) {
1049                         hammer2_write_bp(chain, bp, ioflag, pblksize,
1050                                          mtid, errorp, check_algo);
1051                 } /* else dedup occurred */
1052                 if (chain) {
1053                         hammer2_chain_unlock(chain);
1054                         hammer2_chain_drop(chain);
1055                 }
1056         }
1057 }
1058
1059 /*
1060  * Helper
1061  *
1062  * A function to test whether a block of data contains only zeros,
1063  * returns TRUE (non-zero) if the block is all zeros.
1064  */
1065 static
1066 int
1067 test_block_zeros(const char *buf, size_t bytes)
1068 {
1069         size_t i;
1070
1071         for (i = 0; i < bytes; i += sizeof(long)) {
1072                 if (*(const long *)(buf + i) != 0)
1073                         return (0);
1074         }
1075         return (1);
1076 }
1077
1078 /*
1079  * Helper
1080  *
1081  * Function to "write" a block that contains only zeros.
1082  */
1083 static
1084 void
1085 zero_write(struct buf *bp, hammer2_inode_t *ip,
1086            hammer2_chain_t **parentp,
1087            hammer2_key_t lbase, hammer2_tid_t mtid, int *errorp __unused)
1088 {
1089         hammer2_chain_t *chain;
1090         hammer2_key_t key_dummy;
1091         int cache_index = -1;
1092
1093         chain = hammer2_chain_lookup(parentp, &key_dummy,
1094                                      lbase, lbase,
1095                                      &cache_index,
1096                                      HAMMER2_LOOKUP_NODATA);
1097         if (chain) {
1098                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1099                         hammer2_inode_data_t *wipdata;
1100
1101                         hammer2_chain_modify_ip(ip, chain, mtid, 0);
1102                         wipdata = &chain->data->ipdata;
1103                         KKASSERT(wipdata->meta.op_flags &
1104                                  HAMMER2_OPFLAG_DIRECTDATA);
1105                         KKASSERT(bp->b_loffset == 0);
1106                         bzero(wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1107                         ++hammer2_iod_file_wembed;
1108                 } else {
1109                         hammer2_chain_delete(*parentp, chain,
1110                                              mtid, HAMMER2_DELETE_PERMANENT);
1111                         ++hammer2_iod_file_wzero;
1112                 }
1113                 hammer2_chain_unlock(chain);
1114                 hammer2_chain_drop(chain);
1115         } else {
1116                 ++hammer2_iod_file_wzero;
1117         }
1118 }
1119
1120 /*
1121  * Helper
1122  *
1123  * Function to write the data as it is, without performing any sort of
1124  * compression. This function is used in path without compression and
1125  * default zero-checking path.
1126  */
1127 static
1128 void
1129 hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp, int ioflag,
1130                  int pblksize,
1131                  hammer2_tid_t mtid, int *errorp, int check_algo)
1132 {
1133         hammer2_inode_data_t *wipdata;
1134         hammer2_io_t *dio;
1135         char *bdata;
1136         int error;
1137
1138         error = 0;      /* XXX TODO below */
1139
1140         KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1141
1142         switch(chain->bref.type) {
1143         case HAMMER2_BREF_TYPE_INODE:
1144                 wipdata = &chain->data->ipdata;
1145                 KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
1146                 KKASSERT(bp->b_loffset == 0);
1147                 bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1148                 error = 0;
1149                 ++hammer2_iod_file_wembed;
1150                 break;
1151         case HAMMER2_BREF_TYPE_DATA:
1152                 error = hammer2_io_newnz(chain->hmp,
1153                                          chain->bref.data_off,
1154                                          chain->bytes, &dio);
1155                 if (error) {
1156                         hammer2_io_bqrelse(&dio);
1157                         kprintf("hammer2: WRITE PATH: "
1158                                 "dbp bread error\n");
1159                         break;
1160                 }
1161                 bdata = hammer2_io_data(dio, chain->bref.data_off);
1162
1163                 chain->bref.methods = HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
1164                                       HAMMER2_ENC_CHECK(check_algo);
1165                 bcopy(bp->b_data, bdata, chain->bytes);
1166
1167                 /*
1168                  * The flush code doesn't calculate check codes for
1169                  * file data (doing so can result in excessive I/O),
1170                  * so we do it here.
1171                  *
1172                  * Record for dedup only after the DIO's buffer cache
1173                  * buffer has been updated.
1174                  */
1175                 hammer2_chain_setcheck(chain, bdata);
1176                 hammer2_dedup_record(chain, bdata);
1177
1178                 /*
1179                  * Device buffer is now valid, chain is no longer in
1180                  * the initial state.
1181                  *
1182                  * (No blockref table worries with file data)
1183                  */
1184                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1185
1186                 if (ioflag & IO_SYNC) {
1187                         /*
1188                          * Synchronous I/O requested.
1189                          */
1190                         hammer2_io_bwrite(&dio);
1191                 /*
1192                 } else if ((ioflag & IO_DIRECT) &&
1193                            loff + n == pblksize) {
1194                         hammer2_io_bdwrite(&dio);
1195                 */
1196                 } else if (ioflag & IO_ASYNC) {
1197                         hammer2_io_bawrite(&dio);
1198                 } else {
1199                         hammer2_io_bdwrite(&dio);
1200                 }
1201                 break;
1202         default:
1203                 panic("hammer2_write_bp: bad chain type %d\n",
1204                       chain->bref.type);
1205                 /* NOT REACHED */
1206                 error = 0;
1207                 break;
1208         }
1209         KKASSERT(error == 0);   /* XXX TODO */
1210         *errorp = error;
1211 }
1212
1213 /*
1214  * LIVE DEDUP HEURISTIC
1215  *
1216  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1217  *          All fields must be loaded into locals and validated.
1218  */
1219 static
1220 void
1221 hammer2_dedup_record(hammer2_chain_t *chain, char *data)
1222 {
1223         hammer2_dev_t *hmp;
1224         hammer2_dedup_t *dedup;
1225         int32_t crc;
1226         int best = 0;
1227         int i;
1228         int dticks;
1229
1230         hmp = chain->hmp;
1231         crc = hammer2_icrc32(data, chain->bytes);
1232         dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1233         for (i = 0; i < 4; ++i) {
1234                 if (dedup[i].data_crc == crc) {
1235                         best = i;
1236                         break;
1237                 }
1238                 dticks = (int)(dedup[i].ticks - dedup[best].ticks);
1239                 if (dticks < 0 || dticks > hz * 60 * 30)
1240                         best = i;
1241         }
1242         dedup += best;
1243         if (hammer2_debug & 0x40000) {
1244                 kprintf("REC %04x %08x %016jx\n",
1245                         (int)(dedup - hmp->heur_dedup),
1246                         crc,
1247                         chain->bref.data_off);
1248         }
1249         dedup->ticks = ticks;
1250         dedup->data_off = chain->bref.data_off;
1251         dedup->data_crc = crc;
1252         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DEDUP);
1253 }
1254
1255 static
1256 hammer2_off_t
1257 hammer2_dedup_lookup(hammer2_dev_t *hmp, char **datap, int pblksize)
1258 {
1259         hammer2_dedup_t *dedup;
1260         hammer2_io_t *dio;
1261         hammer2_off_t off;
1262         uint32_t crc;
1263         char *data;
1264         int i;
1265
1266         data = *datap;
1267         if (data == NULL)
1268                 return 0;
1269
1270         crc = hammer2_icrc32(data, pblksize);
1271         dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1272
1273         if (hammer2_debug & 0x40000) {
1274                 kprintf("LOC %04x/4 %08x\n",
1275                         (int)(dedup - hmp->heur_dedup),
1276                         crc);
1277         }
1278
1279         for (i = 0; i < 4; ++i) {
1280                 off = dedup[i].data_off;
1281                 cpu_ccfence();
1282                 if (dedup[i].data_crc != crc)
1283                         continue;
1284                 if ((1 << (int)(off & HAMMER2_OFF_MASK_RADIX)) != pblksize)
1285                         continue;
1286                 dio = hammer2_io_getquick(hmp, off, pblksize);
1287                 if (dio &&
1288                     bcmp(data, hammer2_io_data(dio, off), pblksize) == 0) {
1289                         if (hammer2_debug & 0x40000) {
1290                                 kprintf("DEDUP SUCCESS %016jx\n",
1291                                         (intmax_t)off);
1292                         }
1293                         hammer2_io_putblk(&dio);
1294                         *datap = NULL;
1295                         dedup[i].ticks = ticks; /* update use */
1296                         ++hammer2_iod_file_wdedup;
1297                         return off;             /* RETURN */
1298                 }
1299                 if (dio)
1300                         hammer2_io_putblk(&dio);
1301         }
1302         return 0;
1303 }
1304
1305 /*
1306  * Poof.  Races are ok, if someone gets in and reuses a dedup offset
1307  * before or while we are clearing it they will also recover the freemap
1308  * entry (set it to fully allocated), so a bulkfree race can only set it
1309  * to a possibly-free state.
1310  *
1311  * XXX ok, well, not really sure races are ok but going to run with it
1312  *     for the moment.
1313  */
1314 void
1315 hammer2_dedup_clear(hammer2_dev_t *hmp)
1316 {
1317         int i;
1318
1319         for (i = 0; i < HAMMER2_DEDUP_HEUR_SIZE; ++i) {
1320                 hmp->heur_dedup[i].data_off = 0;
1321                 hmp->heur_dedup[i].ticks = ticks - 1;
1322         }
1323 }