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
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/kernel.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/buf.h>
  46 #include <sys/proc.h>
  47 #include <sys/namei.h>
  48 #include <sys/mount.h>
  49 #include <sys/vnode.h>
  50 #include <sys/mountctl.h>
  51 #include <sys/dirent.h>
  52 #include <sys/uio.h>
  53 #include <sys/objcache.h>
  54 #include <sys/event.h>
  55 #include <sys/file.h>
  56 #include <vfs/fifofs/fifo.h>
  57
  58 #include "hammer2.h"
  59 #include "hammer2_lz4.h"
  60
  61 #include "zlib/hammer2_zlib.h"
  62
  63 struct objcache *cache_buffer_read;
  64 struct objcache *cache_buffer_write;
  65
  66 /*
  67  * Strategy code (async logical file buffer I/O from system)
  68  *
  69  * WARNING: The strategy code cannot safely use hammer2 transactions
  70  *          as this can deadlock against vfs_sync's vfsync() call
  71  *          if multiple flushes are queued.  All H2 structures must
  72  *          already be present and ready for the DIO.
  73  *
  74  *          Reads can be initiated asynchronously, writes have to be
  75  *          spooled to a separate thread for action to avoid deadlocks.
  76  */
  77 static void hammer2_strategy_xop_read(hammer2_xop_t *arg, int clindex);
  78 static void hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex);
  79 static int hammer2_strategy_read(struct vop_strategy_args *ap);
  80 static int hammer2_strategy_write(struct vop_strategy_args *ap);
  81 static void hammer2_strategy_read_completion(hammer2_chain_t *chain,
  82                                 char *data, struct bio *bio);
  83
  84 int
  85 hammer2_vop_strategy(struct vop_strategy_args *ap)
  86 {
  87         struct bio *biop;
  88         struct buf *bp;
  89         int error;
  90
  91         biop = ap->a_bio;
  92         bp = biop->bio_buf;
  93
  94         switch(bp->b_cmd) {
  95         case BUF_CMD_READ:
  96                 error = hammer2_strategy_read(ap);
  97                 ++hammer2_iod_file_read;
  98                 break;
  99         case BUF_CMD_WRITE:
 100                 error = hammer2_strategy_write(ap);
 101                 ++hammer2_iod_file_write;
 102                 break;
 103         default:
 104                 bp->b_error = error = EINVAL;
 105                 bp->b_flags |= B_ERROR;
 106                 biodone(biop);
 107                 break;
 108         }
 109         return (error);
 110 }
 111
 112 /*
 113  * Return the largest contiguous physical disk range for the logical
 114  * request, in bytes.
 115  *
 116  * (struct vnode *vp, off_t loffset, off_t *doffsetp, int *runp, int *runb)
 117  *
 118  * Basically disabled, the logical buffer write thread has to deal with
 119  * buffers one-at-a-time.
 120  */
 121 int
 122 hammer2_vop_bmap(struct vop_bmap_args *ap)
 123 {
 124         *ap->a_doffsetp = NOOFFSET;
 125         if (ap->a_runp)
 126                 *ap->a_runp = 0;
 127         if (ap->a_runb)
 128                 *ap->a_runb = 0;
 129         return (EOPNOTSUPP);
 130 }
 131
 132 /****************************************************************************
 133  *                              READ SUPPORT                                *
 134  ****************************************************************************/
 135 /*
 136  * Callback used in read path in case that a block is compressed with LZ4.
 137  */
 138 static
 139 void
 140 hammer2_decompress_LZ4_callback(const char *data, u_int bytes, struct bio *bio)
 141 {
 142         struct buf *bp;
 143         char *compressed_buffer;
 144         int compressed_size;
 145         int result;
 146
 147         bp = bio->bio_buf;
 148
 149 #if 0
 150         if bio->bio_caller_info2.index &&
 151               bio->bio_caller_info1.uvalue32 !=
 152               crc32(bp->b_data, bp->b_bufsize) --- return error
 153 #endif
 154
 155         KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
 156         compressed_size = *(const int *)data;
 157         KKASSERT(compressed_size <= bytes - sizeof(int));
 158
 159         compressed_buffer = objcache_get(cache_buffer_read, M_INTWAIT);
 160         result = LZ4_decompress_safe(__DECONST(char *, &data[sizeof(int)]),
 161                                      compressed_buffer,
 162                                      compressed_size,
 163                                      bp->b_bufsize);
 164         if (result < 0) {
 165                 kprintf("READ PATH: Error during decompression."
 166                         "bio %016jx/%d\n",
 167                         (intmax_t)bio->bio_offset, bytes);
 168                 /* make sure it isn't random garbage */
 169                 bzero(compressed_buffer, bp->b_bufsize);
 170         }
 171         KKASSERT(result <= bp->b_bufsize);
 172         bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
 173         if (result < bp->b_bufsize)
 174                 bzero(bp->b_data + result, bp->b_bufsize - result);
 175         objcache_put(cache_buffer_read, compressed_buffer);
 176         bp->b_resid = 0;
 177         bp->b_flags |= B_AGE;
 178 }
 179
 180 /*
 181  * Callback used in read path in case that a block is compressed with ZLIB.
 182  * It is almost identical to LZ4 callback, so in theory they can be unified,
 183  * but we didn't want to make changes in bio structure for that.
 184  */
 185 static
 186 void
 187 hammer2_decompress_ZLIB_callback(const char *data, u_int bytes, struct bio *bio)
 188 {
 189         struct buf *bp;
 190         char *compressed_buffer;
 191         z_stream strm_decompress;
 192         int result;
 193         int ret;
 194
 195         bp = bio->bio_buf;
 196
 197         KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
 198         strm_decompress.avail_in = 0;
 199         strm_decompress.next_in = Z_NULL;
 200
 201         ret = inflateInit(&strm_decompress);
 202
 203         if (ret != Z_OK)
 204                 kprintf("HAMMER2 ZLIB: Fatal error in inflateInit.\n");
 205
 206         compressed_buffer = objcache_get(cache_buffer_read, M_INTWAIT);
 207         strm_decompress.next_in = __DECONST(char *, data);
 208
 209         /* XXX supply proper size, subset of device bp */
 210         strm_decompress.avail_in = bytes;
 211         strm_decompress.next_out = compressed_buffer;
 212         strm_decompress.avail_out = bp->b_bufsize;
 213
 214         ret = inflate(&strm_decompress, Z_FINISH);
 215         if (ret != Z_STREAM_END) {
 216                 kprintf("HAMMER2 ZLIB: Fatar error during decompression.\n");
 217                 bzero(compressed_buffer, bp->b_bufsize);
 218         }
 219         bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
 220         result = bp->b_bufsize - strm_decompress.avail_out;
 221         if (result < bp->b_bufsize)
 222                 bzero(bp->b_data + result, strm_decompress.avail_out);
 223         objcache_put(cache_buffer_read, compressed_buffer);
 224         ret = inflateEnd(&strm_decompress);
 225
 226         bp->b_resid = 0;
 227         bp->b_flags |= B_AGE;
 228 }
 229
 230 /*
 231  * Logical buffer I/O, async read.
 232  */
 233 static
 234 int
 235 hammer2_strategy_read(struct vop_strategy_args *ap)
 236 {
 237         hammer2_xop_strategy_t *xop;
 238         struct buf *bp;
 239         struct bio *bio;
 240         struct bio *nbio;
 241         hammer2_inode_t *ip;
 242         hammer2_key_t lbase;
 243
 244         bio = ap->a_bio;
 245         bp = bio->bio_buf;
 246         ip = VTOI(ap->a_vp);
 247         nbio = push_bio(bio);
 248
 249         lbase = bio->bio_offset;
 250         KKASSERT(((int)lbase & HAMMER2_PBUFMASK) == 0);
 251
 252         xop = &hammer2_xop_alloc(ip)->xop_strategy;
 253         xop->finished = 0;
 254         xop->bio = bio;
 255         xop->lbase = lbase;
 256         hammer2_xop_start(&xop->head, hammer2_strategy_xop_read);
 257
 258         return(0);
 259 }
 260
 261 /*
 262  * Per-node XOP (threaded), do a synchronous lookup of the chain and
 263  * its data.  The frontend is asynchronous, so we are also responsible
 264  * for racing to terminate the frontend.
 265  */
 266 static
 267 void
 268 hammer2_strategy_xop_read(hammer2_xop_t *arg, int clindex)
 269 {
 270         hammer2_xop_strategy_t *xop = &arg->xop_strategy;
 271         hammer2_chain_t *parent;
 272         hammer2_chain_t *chain;
 273         hammer2_key_t key_dummy;
 274         hammer2_key_t lbase;
 275         struct bio *bio;
 276         struct buf *bp;
 277         int cache_index = -1;
 278         int error;
 279
 280         lbase = xop->lbase;
 281         bio = xop->bio;
 282         bp = bio->bio_buf;
 283
 284         parent = hammer2_inode_chain(xop->head.ip, clindex,
 285                                      HAMMER2_RESOLVE_ALWAYS |
 286                                      HAMMER2_RESOLVE_SHARED);
 287         if (parent) {
 288                 chain = hammer2_chain_lookup(&parent, &key_dummy,
 289                                              lbase, lbase,
 290                                              &cache_index,
 291                                              HAMMER2_LOOKUP_ALWAYS |
 292                                              HAMMER2_LOOKUP_SHARED);
 293                 error = chain ? chain->error : 0;
 294         } else {
 295                 error = EIO;
 296                 chain = NULL;
 297         }
 298         error = hammer2_xop_feed(&xop->head, chain, clindex, error);
 299         if (chain)
 300                 hammer2_chain_drop(chain);
 301         if (parent) {
 302                 hammer2_chain_unlock(parent);
 303                 hammer2_chain_drop(parent);
 304         }
 305         chain = NULL;   /* safety */
 306         parent = NULL;  /* safety */
 307
 308         /*
 309          * Race to finish the frontend
 310          */
 311         if (xop->finished)
 312                 return;
 313         hammer2_mtx_ex(&xop->head.xgrp->mtx2);
 314         if (xop->finished) {
 315                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 316                 return;
 317         }
 318
 319         /*
 320          * Async operation has not completed and we now own the lock.
 321          * Determine if we can complete the operation by issuing the
 322          * frontend collection non-blocking.
 323          */
 324         error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
 325
 326         switch(error) {
 327         case 0:
 328                 xop->finished = 1;
 329                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 330                 chain = xop->head.cluster.focus;
 331                 hammer2_strategy_read_completion(chain, (char *)chain->data,
 332                                                  xop->bio);
 333                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 334                 biodone(bio);
 335                 break;
 336         case ENOENT:
 337                 xop->finished = 1;
 338                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 339                 bp->b_resid = 0;
 340                 bp->b_error = 0;
 341                 bzero(bp->b_data, bp->b_bcount);
 342                 biodone(bio);
 343                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 344                 break;
 345         case EINPROGRESS:
 346                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 347                 break;
 348         default:
 349                 xop->finished = 1;
 350                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 351                 bp->b_flags |= B_ERROR;
 352                 bp->b_error = EIO;
 353                 biodone(bio);
 354                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 355                 break;
 356         }
 357 }
 358
 359 static
 360 void
 361 hammer2_strategy_read_completion(hammer2_chain_t *chain, char *data,
 362                                  struct bio *bio)
 363 {
 364         struct buf *bp = bio->bio_buf;
 365
 366         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 367                 /*
 368                  * Data is embedded in the inode (copy from inode).
 369                  */
 370                 bcopy(((hammer2_inode_data_t *)data)->u.data,
 371                       bp->b_data, HAMMER2_EMBEDDED_BYTES);
 372                 bzero(bp->b_data + HAMMER2_EMBEDDED_BYTES,
 373                       bp->b_bcount - HAMMER2_EMBEDDED_BYTES);
 374                 bp->b_resid = 0;
 375                 bp->b_error = 0;
 376         } else if (chain->bref.type == HAMMER2_BREF_TYPE_DATA) {
 377                 /*
 378                  * Data is on-media, issue device I/O and copy.
 379                  *
 380                  * XXX direct-IO shortcut could go here XXX.
 381                  */
 382                 switch (HAMMER2_DEC_COMP(chain->bref.methods)) {
 383                 case HAMMER2_COMP_LZ4:
 384                         hammer2_decompress_LZ4_callback(data, chain->bytes,
 385                                                         bio);
 386                         break;
 387                 case HAMMER2_COMP_ZLIB:
 388                         hammer2_decompress_ZLIB_callback(data, chain->bytes,
 389                                                          bio);
 390                         break;
 391                 case HAMMER2_COMP_NONE:
 392                         KKASSERT(chain->bytes <= bp->b_bcount);
 393                         bcopy(data, bp->b_data, chain->bytes);
 394                         if (chain->bytes < bp->b_bcount) {
 395                                 bzero(bp->b_data + chain->bytes,
 396                                       bp->b_bcount - chain->bytes);
 397                         }
 398                         bp->b_flags |= B_NOTMETA;
 399                         bp->b_resid = 0;
 400                         bp->b_error = 0;
 401                         break;
 402                 default:
 403                         panic("hammer2_strategy_read: "
 404                               "unknown compression type");
 405                 }
 406         } else {
 407                 panic("hammer2_strategy_read: unknown bref type");
 408         }
 409 }
 410
 411 /****************************************************************************
 412  *                              WRITE SUPPORT                               *
 413  ****************************************************************************/
 414
 415 /*
 416  * Functions for compression in threads,
 417  * from hammer2_vnops.c
 418  */
 419 static void hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
 420                                 hammer2_chain_t **parentp,
 421                                 hammer2_key_t lbase, int ioflag, int pblksize,
 422                                 int *errorp);
 423 static void hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
 424                                 hammer2_chain_t **parentp,
 425                                 hammer2_key_t lbase, int ioflag,
 426                                 int pblksize, int *errorp,
 427                                 int comp_algo, int check_algo);
 428 static void hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
 429                                 hammer2_chain_t **parentp,
 430                                 hammer2_key_t lbase,
 431                                 int ioflag, int pblksize, int *errorp,
 432                                 int check_algo);
 433 static int test_block_zeros(const char *buf, size_t bytes);
 434 static void zero_write(struct buf *bp, hammer2_inode_t *ip,
 435                                 hammer2_chain_t **parentp,
 436                                 hammer2_key_t lbase,
 437                                 int *errorp);
 438 static void hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp,
 439                                 int ioflag, int pblksize, int *errorp,
 440                                 int check_algo);
 441
 442 static
 443 int
 444 hammer2_strategy_write(struct vop_strategy_args *ap)
 445 {
 446         hammer2_xop_strategy_t *xop;
 447         hammer2_pfs_t *pmp;
 448         struct bio *bio;
 449         struct buf *bp;
 450         hammer2_inode_t *ip;
 451
 452         bio = ap->a_bio;
 453         bp = bio->bio_buf;
 454         ip = VTOI(ap->a_vp);
 455         pmp = ip->pmp;
 456
 457         hammer2_lwinprog_ref(pmp);
 458         hammer2_trans_assert_strategy(pmp);
 459
 460         xop = &hammer2_xop_alloc(ip)->xop_strategy;
 461         xop->finished = 0;
 462         xop->bio = bio;
 463         xop->lbase = bio->bio_offset;
 464         hammer2_xop_start(&xop->head, hammer2_strategy_xop_write);
 465         /* asynchronous completion */
 466
 467         hammer2_lwinprog_wait(pmp, hammer2_flush_pipe);
 468
 469         return(0);
 470 }
 471
 472 /*
 473  * Per-node XOP (threaded).  Write the logical buffer to the media.
 474  */
 475 static
 476 void
 477 hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex)
 478 {
 479         hammer2_xop_strategy_t *xop = &arg->xop_strategy;
 480         hammer2_chain_t *parent;
 481         hammer2_key_t lbase;
 482         hammer2_inode_t *ip;
 483         struct bio *bio;
 484         struct buf *bp;
 485         int error;
 486         int lblksize;
 487         int pblksize;
 488
 489         lbase = xop->lbase;
 490         bio = xop->bio;
 491         bp = bio->bio_buf;
 492         ip = xop->head.ip;
 493
 494         /* hammer2_trans_init(parent->hmp->spmp, HAMMER2_TRANS_BUFCACHE); */
 495
 496         lblksize = hammer2_calc_logical(ip, bio->bio_offset, &lbase, NULL);
 497         pblksize = hammer2_calc_physical(ip, lbase);
 498         parent = hammer2_inode_chain(ip, clindex, HAMMER2_RESOLVE_ALWAYS);
 499         hammer2_write_file_core(bp, ip, &parent,
 500                                 lbase, IO_ASYNC,
 501                                 pblksize, &error);
 502         if (parent) {
 503                 hammer2_chain_unlock(parent);
 504                 hammer2_chain_drop(parent);
 505                 parent = NULL;  /* safety */
 506         }
 507         error = hammer2_xop_feed(&xop->head, NULL, clindex, error);
 508
 509         /*
 510          * Race to finish the frontend
 511          */
 512         if (xop->finished)
 513                 return;
 514         hammer2_mtx_ex(&xop->head.xgrp->mtx2);
 515         if (xop->finished) {
 516                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 517                 return;
 518         }
 519
 520         /*
 521          * Async operation has not completed and we now own the lock.
 522          * Determine if we can complete the operation by issuing the
 523          * frontend collection non-blocking.
 524          */
 525         error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
 526
 527         switch(error) {
 528         case ENOENT:
 529         case 0:
 530                 xop->finished = 1;
 531                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 532                 bp->b_resid = 0;
 533                 bp->b_error = 0;
 534                 biodone(bio);
 535                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 536                 hammer2_lwinprog_drop(ip->pmp);
 537                 break;
 538         case EINPROGRESS:
 539                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 540                 break;
 541         default:
 542                 xop->finished = 1;
 543                 hammer2_mtx_unlock(&xop->head.xgrp->mtx2);
 544                 bp->b_flags |= B_ERROR;
 545                 bp->b_error = EIO;
 546                 biodone(bio);
 547                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
 548                 hammer2_lwinprog_drop(ip->pmp);
 549                 break;
 550         }
 551 }
 552
 553 /*
 554  * Wait for pending I/O to complete
 555  */
 556 void
 557 hammer2_bioq_sync(hammer2_pfs_t *pmp)
 558 {
 559         hammer2_lwinprog_wait(pmp, 0);
 560 }
 561
 562 /*
 563  * Create a new cluster at (cparent, lbase) and assign physical storage,
 564  * returning a cluster suitable for I/O.  The cluster will be in a modified
 565  * state.
 566  *
 567  * cparent can wind up being anything.
 568  *
 569  * NOTE: Special case for data embedded in inode.
 570  */
 571 static
 572 hammer2_chain_t *
 573 hammer2_assign_physical(hammer2_inode_t *ip, hammer2_chain_t **parentp,
 574                         hammer2_key_t lbase, int pblksize, int *errorp)
 575 {
 576         hammer2_chain_t *chain;
 577         hammer2_key_t key_dummy;
 578         int pradix = hammer2_getradix(pblksize);
 579         int cache_index = -1;
 580
 581         /*
 582          * Locate the chain associated with lbase, return a locked chain.
 583          * However, do not instantiate any data reference (which utilizes a
 584          * device buffer) because we will be using direct IO via the
 585          * logical buffer cache buffer.
 586          */
 587         *errorp = 0;
 588         KKASSERT(pblksize >= HAMMER2_ALLOC_MIN);
 589 retry:
 590         chain = hammer2_chain_lookup(parentp, &key_dummy,
 591                                      lbase, lbase,
 592                                      &cache_index,
 593                                      HAMMER2_LOOKUP_NODATA);
 594         if (chain == NULL) {
 595                 /*
 596                  * We found a hole, create a new chain entry.
 597                  *
 598                  * NOTE: DATA chains are created without device backing
 599                  *       store (nor do we want any).
 600                  */
 601                 *errorp = hammer2_chain_create(parentp, &chain, ip->pmp,
 602                                                lbase, HAMMER2_PBUFRADIX,
 603                                                HAMMER2_BREF_TYPE_DATA,
 604                                                pblksize, 0);
 605                 if (chain == NULL) {
 606                         panic("hammer2_chain_create: par=%p error=%d\n",
 607                               *parentp, *errorp);
 608                         goto retry;
 609                 }
 610                 /*ip->delta_dcount += pblksize;*/
 611         } else {
 612                 switch (chain->bref.type) {
 613                 case HAMMER2_BREF_TYPE_INODE:
 614                         /*
 615                          * The data is embedded in the inode, which requires
 616                          * a bit more finess.
 617                          */
 618                         hammer2_chain_modify_ip(ip, chain, 0);
 619                         break;
 620                 case HAMMER2_BREF_TYPE_DATA:
 621                         if (chain->bytes != pblksize) {
 622                                 hammer2_chain_resize(ip, *parentp, chain,
 623                                                      pradix,
 624                                                      HAMMER2_MODIFY_OPTDATA);
 625                         }
 626
 627                         /*
 628                          * DATA buffers must be marked modified whether the
 629                          * data is in a logical buffer or not.  We also have
 630                          * to make this call to fixup the chain data pointers
 631                          * after resizing in case this is an encrypted or
 632                          * compressed buffer.
 633                          */
 634                         hammer2_chain_modify(chain, HAMMER2_MODIFY_OPTDATA);
 635                         break;
 636                 default:
 637                         panic("hammer2_assign_physical: bad type");
 638                         /* NOT REACHED */
 639                         break;
 640                 }
 641         }
 642         return (chain);
 643 }
 644
 645 /*
 646  * hammer2_write_file_core() - hammer2_write_thread() helper
 647  *
 648  * The core write function which determines which path to take
 649  * depending on compression settings.  We also have to locate the
 650  * related chains so we can calculate and set the check data for
 651  * the blockref.
 652  */
 653 static
 654 void
 655 hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
 656                         hammer2_chain_t **parentp,
 657                         hammer2_key_t lbase, int ioflag, int pblksize,
 658                         int *errorp)
 659 {
 660         hammer2_chain_t *chain;
 661
 662         switch(HAMMER2_DEC_ALGO(ip->meta.comp_algo)) {
 663         case HAMMER2_COMP_NONE:
 664                 /*
 665                  * We have to assign physical storage to the buffer
 666                  * we intend to dirty or write now to avoid deadlocks
 667                  * in the strategy code later.
 668                  *
 669                  * This can return NOOFFSET for inode-embedded data.
 670                  * The strategy code will take care of it in that case.
 671                  */
 672                 chain = hammer2_assign_physical(ip, parentp,
 673                                                 lbase, pblksize, errorp);
 674                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 675                         hammer2_inode_data_t *wipdata;
 676
 677                         wipdata = &chain->data->ipdata;
 678                         KKASSERT(wipdata->meta.op_flags &
 679                                  HAMMER2_OPFLAG_DIRECTDATA);
 680                         KKASSERT(bp->b_loffset == 0);
 681                         bcopy(bp->b_data, wipdata->u.data,
 682                               HAMMER2_EMBEDDED_BYTES);
 683                 } else {
 684                         hammer2_write_bp(chain, bp, ioflag, pblksize,
 685                                          errorp, ip->meta.check_algo);
 686                 }
 687                 if (chain) {
 688                         hammer2_chain_unlock(chain);
 689                         hammer2_chain_drop(chain);
 690                 }
 691                 break;
 692         case HAMMER2_COMP_AUTOZERO:
 693                 /*
 694                  * Check for zero-fill only
 695                  */
 696                 hammer2_zero_check_and_write(bp, ip, parentp,
 697                                              lbase, ioflag,
 698                                              pblksize, errorp,
 699                                              ip->meta.check_algo);
 700                 break;
 701         case HAMMER2_COMP_LZ4:
 702         case HAMMER2_COMP_ZLIB:
 703         default:
 704                 /*
 705                  * Check for zero-fill and attempt compression.
 706                  */
 707                 hammer2_compress_and_write(bp, ip, parentp,
 708                                            lbase, ioflag,
 709                                            pblksize, errorp,
 710                                            ip->meta.comp_algo,
 711                                            ip->meta.check_algo);
 712                 break;
 713         }
 714 }
 715
 716 /*
 717  * Helper
 718  *
 719  * Generic function that will perform the compression in compression
 720  * write path. The compression algorithm is determined by the settings
 721  * obtained from inode.
 722  */
 723 static
 724 void
 725 hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
 726         hammer2_chain_t **parentp,
 727         hammer2_key_t lbase, int ioflag, int pblksize,
 728         int *errorp, int comp_algo, int check_algo)
 729 {
 730         hammer2_chain_t *chain;
 731         int comp_size;
 732         int comp_block_size;
 733         char *comp_buffer;
 734
 735         if (test_block_zeros(bp->b_data, pblksize)) {
 736                 zero_write(bp, ip, parentp, lbase, errorp);
 737                 return;
 738         }
 739
 740         comp_size = 0;
 741         comp_buffer = NULL;
 742
 743         KKASSERT(pblksize / 2 <= 32768);
 744
 745         if (ip->comp_heuristic < 8 || (ip->comp_heuristic & 7) == 0) {
 746                 z_stream strm_compress;
 747                 int comp_level;
 748                 int ret;
 749
 750                 switch(HAMMER2_DEC_ALGO(comp_algo)) {
 751                 case HAMMER2_COMP_LZ4:
 752                         comp_buffer = objcache_get(cache_buffer_write,
 753                                                    M_INTWAIT);
 754                         comp_size = LZ4_compress_limitedOutput(
 755                                         bp->b_data,
 756                                         &comp_buffer[sizeof(int)],
 757                                         pblksize,
 758                                         pblksize / 2 - sizeof(int));
 759                         /*
 760                          * We need to prefix with the size, LZ4
 761                          * doesn't do it for us.  Add the related
 762                          * overhead.
 763                          */
 764                         *(int *)comp_buffer = comp_size;
 765                         if (comp_size)
 766                                 comp_size += sizeof(int);
 767                         break;
 768                 case HAMMER2_COMP_ZLIB:
 769                         comp_level = HAMMER2_DEC_LEVEL(comp_algo);
 770                         if (comp_level == 0)
 771                                 comp_level = 6; /* default zlib compression */
 772                         else if (comp_level < 6)
 773                                 comp_level = 6;
 774                         else if (comp_level > 9)
 775                                 comp_level = 9;
 776                         ret = deflateInit(&strm_compress, comp_level);
 777                         if (ret != Z_OK) {
 778                                 kprintf("HAMMER2 ZLIB: fatal error "
 779                                         "on deflateInit.\n");
 780                         }
 781
 782                         comp_buffer = objcache_get(cache_buffer_write,
 783                                                    M_INTWAIT);
 784                         strm_compress.next_in = bp->b_data;
 785                         strm_compress.avail_in = pblksize;
 786                         strm_compress.next_out = comp_buffer;
 787                         strm_compress.avail_out = pblksize / 2;
 788                         ret = deflate(&strm_compress, Z_FINISH);
 789                         if (ret == Z_STREAM_END) {
 790                                 comp_size = pblksize / 2 -
 791                                             strm_compress.avail_out;
 792                         } else {
 793                                 comp_size = 0;
 794                         }
 795                         ret = deflateEnd(&strm_compress);
 796                         break;
 797                 default:
 798                         kprintf("Error: Unknown compression method.\n");
 799                         kprintf("Comp_method = %d.\n", comp_algo);
 800                         break;
 801                 }
 802         }
 803
 804         if (comp_size == 0) {
 805                 /*
 806                  * compression failed or turned off
 807                  */
 808                 comp_block_size = pblksize;     /* safety */
 809                 if (++ip->comp_heuristic > 128)
 810                         ip->comp_heuristic = 8;
 811         } else {
 812                 /*
 813                  * compression succeeded
 814                  */
 815                 ip->comp_heuristic = 0;
 816                 if (comp_size <= 1024) {
 817                         comp_block_size = 1024;
 818                 } else if (comp_size <= 2048) {
 819                         comp_block_size = 2048;
 820                 } else if (comp_size <= 4096) {
 821                         comp_block_size = 4096;
 822                 } else if (comp_size <= 8192) {
 823                         comp_block_size = 8192;
 824                 } else if (comp_size <= 16384) {
 825                         comp_block_size = 16384;
 826                 } else if (comp_size <= 32768) {
 827                         comp_block_size = 32768;
 828                 } else {
 829                         panic("hammer2: WRITE PATH: "
 830                               "Weird comp_size value.");
 831                         /* NOT REACHED */
 832                         comp_block_size = pblksize;
 833                 }
 834         }
 835
 836         chain = hammer2_assign_physical(ip, parentp, lbase,
 837                                         comp_block_size, errorp);
 838         if (*errorp) {
 839                 kprintf("WRITE PATH: An error occurred while "
 840                         "assigning physical space.\n");
 841                 KKASSERT(chain == NULL);
 842                 goto done;
 843         }
 844
 845         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 846                 hammer2_inode_data_t *wipdata;
 847
 848                 hammer2_chain_modify_ip(ip, chain, 0);
 849                 wipdata = &chain->data->ipdata;
 850                 KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
 851                 KKASSERT(bp->b_loffset == 0);
 852                 bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
 853         } else {
 854                 hammer2_io_t *dio;
 855                 char *bdata;
 856
 857                 KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
 858
 859                 switch(chain->bref.type) {
 860                 case HAMMER2_BREF_TYPE_INODE:
 861                         panic("hammer2_write_bp: unexpected inode\n");
 862                         break;
 863                 case HAMMER2_BREF_TYPE_DATA:
 864                         /*
 865                          * Optimize out the read-before-write
 866                          * if possible.
 867                          */
 868                         *errorp = hammer2_io_newnz(chain->hmp,
 869                                                    chain->bref.data_off,
 870                                                    chain->bytes,
 871                                                    &dio);
 872                         if (*errorp) {
 873                                 hammer2_io_brelse(&dio);
 874                                 kprintf("hammer2: WRITE PATH: "
 875                                         "dbp bread error\n");
 876                                 break;
 877                         }
 878                         bdata = hammer2_io_data(dio, chain->bref.data_off);
 879
 880                         /*
 881                          * When loading the block make sure we don't
 882                          * leave garbage after the compressed data.
 883                          */
 884                         if (comp_size) {
 885                                 chain->bref.methods =
 886                                         HAMMER2_ENC_COMP(comp_algo) +
 887                                         HAMMER2_ENC_CHECK(check_algo);
 888                                 bcopy(comp_buffer, bdata, comp_size);
 889                                 if (comp_size != comp_block_size) {
 890                                         bzero(bdata + comp_size,
 891                                               comp_block_size - comp_size);
 892                                 }
 893                         } else {
 894                                 chain->bref.methods =
 895                                         HAMMER2_ENC_COMP(
 896                                                 HAMMER2_COMP_NONE) +
 897                                         HAMMER2_ENC_CHECK(check_algo);
 898                                 bcopy(bp->b_data, bdata, pblksize);
 899                         }
 900
 901                         /*
 902                          * The flush code doesn't calculate check codes for
 903                          * file data (doing so can result in excessive I/O),
 904                          * so we do it here.
 905                          */
 906                         hammer2_chain_setcheck(chain, bdata);
 907
 908                         /*
 909                          * Device buffer is now valid, chain is no longer in
 910                          * the initial state.
 911                          *
 912                          * (No blockref table worries with file data)
 913                          */
 914                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
 915
 916                         /* Now write the related bdp. */
 917                         if (ioflag & IO_SYNC) {
 918                                 /*
 919                                  * Synchronous I/O requested.
 920                                  */
 921                                 hammer2_io_bwrite(&dio);
 922                         /*
 923                         } else if ((ioflag & IO_DIRECT) &&
 924                                    loff + n == pblksize) {
 925                                 hammer2_io_bdwrite(&dio);
 926                         */
 927                         } else if (ioflag & IO_ASYNC) {
 928                                 hammer2_io_bawrite(&dio);
 929                         } else {
 930                                 hammer2_io_bdwrite(&dio);
 931                         }
 932                         break;
 933                 default:
 934                         panic("hammer2_write_bp: bad chain type %d\n",
 935                                 chain->bref.type);
 936                         /* NOT REACHED */
 937                         break;
 938                 }
 939         }
 940 done:
 941         if (chain) {
 942                 hammer2_chain_unlock(chain);
 943                 hammer2_chain_drop(chain);
 944         }
 945         if (comp_buffer)
 946                 objcache_put(cache_buffer_write, comp_buffer);
 947 }
 948
 949 /*
 950  * Helper
 951  *
 952  * Function that performs zero-checking and writing without compression,
 953  * it corresponds to default zero-checking path.
 954  */
 955 static
 956 void
 957 hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
 958         hammer2_chain_t **parentp,
 959         hammer2_key_t lbase, int ioflag, int pblksize, int *errorp,
 960         int check_algo)
 961 {
 962         hammer2_chain_t *chain;
 963
 964         if (test_block_zeros(bp->b_data, pblksize)) {
 965                 zero_write(bp, ip, parentp, lbase, errorp);
 966         } else {
 967                 chain = hammer2_assign_physical(ip, parentp, lbase,
 968                                                 pblksize, errorp);
 969                 hammer2_write_bp(chain, bp, ioflag, pblksize,
 970                                  errorp, check_algo);
 971                 if (chain) {
 972                         hammer2_chain_unlock(chain);
 973                         hammer2_chain_drop(chain);
 974                 }
 975         }
 976 }
 977
 978 /*
 979  * Helper
 980  *
 981  * A function to test whether a block of data contains only zeros,
 982  * returns TRUE (non-zero) if the block is all zeros.
 983  */
 984 static
 985 int
 986 test_block_zeros(const char *buf, size_t bytes)
 987 {
 988         size_t i;
 989
 990         for (i = 0; i < bytes; i += sizeof(long)) {
 991                 if (*(const long *)(buf + i) != 0)
 992                         return (0);
 993         }
 994         return (1);
 995 }
 996
 997 /*
 998  * Helper
 999  *
1000  * Function to "write" a block that contains only zeros.
1001  */
1002 static
1003 void
1004 zero_write(struct buf *bp, hammer2_inode_t *ip,
1005            hammer2_chain_t **parentp,
1006            hammer2_key_t lbase, int *errorp __unused)
1007 {
1008         hammer2_chain_t *chain;
1009         hammer2_key_t key_dummy;
1010         int cache_index = -1;
1011
1012         chain = hammer2_chain_lookup(parentp, &key_dummy,
1013                                      lbase, lbase,
1014                                      &cache_index,
1015                                      HAMMER2_LOOKUP_NODATA);
1016         if (chain) {
1017                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1018                         hammer2_inode_data_t *wipdata;
1019
1020                         hammer2_chain_modify_ip(ip, chain, 0);
1021                         wipdata = &chain->data->ipdata;
1022                         KKASSERT(wipdata->meta.op_flags &
1023                                  HAMMER2_OPFLAG_DIRECTDATA);
1024                         KKASSERT(bp->b_loffset == 0);
1025                         bzero(wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1026                 } else {
1027                         hammer2_chain_delete(*parentp, chain,
1028                                              HAMMER2_DELETE_PERMANENT);
1029                 }
1030                 hammer2_chain_unlock(chain);
1031                 hammer2_chain_drop(chain);
1032         }
1033 }
1034
1035 /*
1036  * Helper
1037  *
1038  * Function to write the data as it is, without performing any sort of
1039  * compression. This function is used in path without compression and
1040  * default zero-checking path.
1041  */
1042 static
1043 void
1044 hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp, int ioflag,
1045                  int pblksize, int *errorp, int check_algo)
1046 {
1047         hammer2_inode_data_t *wipdata;
1048         hammer2_io_t *dio;
1049         char *bdata;
1050         int error;
1051
1052         error = 0;      /* XXX TODO below */
1053
1054         KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1055
1056         switch(chain->bref.type) {
1057         case HAMMER2_BREF_TYPE_INODE:
1058                 wipdata = &chain->data->ipdata;
1059                 KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
1060                 KKASSERT(bp->b_loffset == 0);
1061                 bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1062                 error = 0;
1063                 break;
1064         case HAMMER2_BREF_TYPE_DATA:
1065                 error = hammer2_io_newnz(chain->hmp,
1066                                          chain->bref.data_off,
1067                                          chain->bytes, &dio);
1068                 if (error) {
1069                         hammer2_io_bqrelse(&dio);
1070                         kprintf("hammer2: WRITE PATH: "
1071                                 "dbp bread error\n");
1072                         break;
1073                 }
1074                 bdata = hammer2_io_data(dio, chain->bref.data_off);
1075
1076                 chain->bref.methods = HAMMER2_ENC_COMP(
1077                                                 HAMMER2_COMP_NONE) +
1078                                       HAMMER2_ENC_CHECK(check_algo);
1079                 bcopy(bp->b_data, bdata, chain->bytes);
1080
1081                 /*
1082                  * The flush code doesn't calculate check codes for
1083                  * file data (doing so can result in excessive I/O),
1084                  * so we do it here.
1085                  */
1086                 hammer2_chain_setcheck(chain, bdata);
1087
1088                 /*
1089                  * Device buffer is now valid, chain is no longer in
1090                  * the initial state.
1091                  *
1092                  * (No blockref table worries with file data)
1093                  */
1094                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1095
1096                 if (ioflag & IO_SYNC) {
1097                         /*
1098                          * Synchronous I/O requested.
1099                          */
1100                         hammer2_io_bwrite(&dio);
1101                 /*
1102                 } else if ((ioflag & IO_DIRECT) &&
1103                            loff + n == pblksize) {
1104                         hammer2_io_bdwrite(&dio);
1105                 */
1106                 } else if (ioflag & IO_ASYNC) {
1107                         hammer2_io_bawrite(&dio);
1108                 } else {
1109                         hammer2_io_bdwrite(&dio);
1110                 }
1111                 break;
1112         default:
1113                 panic("hammer2_write_bp: bad chain type %d\n",
1114                       chain->bref.type);
1115                 /* NOT REACHED */
1116                 error = 0;
1117                 break;
1118         }
1119         KKASSERT(error == 0);   /* XXX TODO */
1120         *errorp = error;
1121 }