git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/compress.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "bcachefs.h"
   3 #include "checksum.h"
   4 #include "compress.h"
   5 #include "extents.h"
   6 #include "io.h"
   7 #include "super-io.h"
   8
   9 #include <linux/lz4.h>
  10 #include <linux/zlib.h>
  11 #include <linux/zstd.h>
  12
  13 /* Bounce buffer: */
  14 struct bbuf {
  15         void            *b;
  16         enum {
  17                 BB_NONE,
  18                 BB_VMAP,
  19                 BB_KMALLOC,
  20                 BB_MEMPOOL,
  21         }               type;
  22         int             rw;
  23 };
  24
  25 static struct bbuf __bounce_alloc(struct bch_fs *c, unsigned size, int rw)
  26 {
  27         void *b;
  28
  29         BUG_ON(size > c->sb.encoded_extent_max << 9);
  30
  31         b = kmalloc(size, GFP_NOIO|__GFP_NOWARN);
  32         if (b)
  33                 return (struct bbuf) { .b = b, .type = BB_KMALLOC, .rw = rw };
  34
  35         b = mempool_alloc(&c->compression_bounce[rw], GFP_NOIO);
  36         if (b)
  37                 return (struct bbuf) { .b = b, .type = BB_MEMPOOL, .rw = rw };
  38
  39         BUG();
  40 }
  41
  42 static bool bio_phys_contig(struct bio *bio, struct bvec_iter start)
  43 {
  44         struct bio_vec bv;
  45         struct bvec_iter iter;
  46         void *expected_start = NULL;
  47
  48         __bio_for_each_bvec(bv, bio, iter, start) {
  49                 if (expected_start &&
  50                     expected_start != page_address(bv.bv_page) + bv.bv_offset)
  51                         return false;
  52
  53                 expected_start = page_address(bv.bv_page) +
  54                         bv.bv_offset + bv.bv_len;
  55         }
  56
  57         return true;
  58 }
  59
  60 static struct bbuf __bio_map_or_bounce(struct bch_fs *c, struct bio *bio,
  61                                        struct bvec_iter start, int rw)
  62 {
  63         struct bbuf ret;
  64         struct bio_vec bv;
  65         struct bvec_iter iter;
  66         unsigned nr_pages = 0;
  67         struct page *stack_pages[16];
  68         struct page **pages = NULL;
  69         void *data;
  70
  71         BUG_ON(bvec_iter_sectors(start) > c->sb.encoded_extent_max);
  72
  73         if (!IS_ENABLED(CONFIG_HIGHMEM) &&
  74             bio_phys_contig(bio, start))
  75                 return (struct bbuf) {
  76                         .b = page_address(bio_iter_page(bio, start)) +
  77                                 bio_iter_offset(bio, start),
  78                         .type = BB_NONE, .rw = rw
  79                 };
  80
  81         /* check if we can map the pages contiguously: */
  82         __bio_for_each_segment(bv, bio, iter, start) {
  83                 if (iter.bi_size != start.bi_size &&
  84                     bv.bv_offset)
  85                         goto bounce;
  86
  87                 if (bv.bv_len < iter.bi_size &&
  88                     bv.bv_offset + bv.bv_len < PAGE_SIZE)
  89                         goto bounce;
  90
  91                 nr_pages++;
  92         }
  93
  94         BUG_ON(DIV_ROUND_UP(start.bi_size, PAGE_SIZE) > nr_pages);
  95
  96         pages = nr_pages > ARRAY_SIZE(stack_pages)
  97                 ? kmalloc_array(nr_pages, sizeof(struct page *), GFP_NOIO)
  98                 : stack_pages;
  99         if (!pages)
 100                 goto bounce;
 101
 102         nr_pages = 0;
 103         __bio_for_each_segment(bv, bio, iter, start)
 104                 pages[nr_pages++] = bv.bv_page;
 105
 106         data = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
 107         if (pages != stack_pages)
 108                 kfree(pages);
 109
 110         if (data)
 111                 return (struct bbuf) {
 112                         .b = data + bio_iter_offset(bio, start),
 113                         .type = BB_VMAP, .rw = rw
 114                 };
 115 bounce:
 116         ret = __bounce_alloc(c, start.bi_size, rw);
 117
 118         if (rw == READ)
 119                 memcpy_from_bio(ret.b, bio, start);
 120
 121         return ret;
 122 }
 123
 124 static struct bbuf bio_map_or_bounce(struct bch_fs *c, struct bio *bio, int rw)
 125 {
 126         return __bio_map_or_bounce(c, bio, bio->bi_iter, rw);
 127 }
 128
 129 static void bio_unmap_or_unbounce(struct bch_fs *c, struct bbuf buf)
 130 {
 131         switch (buf.type) {
 132         case BB_NONE:
 133                 break;
 134         case BB_VMAP:
 135                 vunmap((void *) ((unsigned long) buf.b & PAGE_MASK));
 136                 break;
 137         case BB_KMALLOC:
 138                 kfree(buf.b);
 139                 break;
 140         case BB_MEMPOOL:
 141                 mempool_free(buf.b, &c->compression_bounce[buf.rw]);
 142                 break;
 143         }
 144 }
 145
 146 static inline void zlib_set_workspace(z_stream *strm, void *workspace)
 147 {
 148 #ifdef __KERNEL__
 149         strm->workspace = workspace;
 150 #endif
 151 }
 152
 153 static int __bio_uncompress(struct bch_fs *c, struct bio *src,
 154                             void *dst_data, struct bch_extent_crc_unpacked crc)
 155 {
 156         struct bbuf src_data = { NULL };
 157         size_t src_len = src->bi_iter.bi_size;
 158         size_t dst_len = crc.uncompressed_size << 9;
 159         void *workspace;
 160         int ret;
 161
 162         src_data = bio_map_or_bounce(c, src, READ);
 163
 164         switch (crc.compression_type) {
 165         case BCH_COMPRESSION_TYPE_lz4_old:
 166         case BCH_COMPRESSION_TYPE_lz4:
 167                 ret = LZ4_decompress_safe_partial(src_data.b, dst_data,
 168                                                   src_len, dst_len, dst_len);
 169                 if (ret != dst_len)
 170                         goto err;
 171                 break;
 172         case BCH_COMPRESSION_TYPE_gzip: {
 173                 z_stream strm = {
 174                         .next_in        = src_data.b,
 175                         .avail_in       = src_len,
 176                         .next_out       = dst_data,
 177                         .avail_out      = dst_len,
 178                 };
 179
 180                 workspace = mempool_alloc(&c->decompress_workspace, GFP_NOIO);
 181
 182                 zlib_set_workspace(&strm, workspace);
 183                 zlib_inflateInit2(&strm, -MAX_WBITS);
 184                 ret = zlib_inflate(&strm, Z_FINISH);
 185
 186                 mempool_free(workspace, &c->decompress_workspace);
 187
 188                 if (ret != Z_STREAM_END)
 189                         goto err;
 190                 break;
 191         }
 192         case BCH_COMPRESSION_TYPE_zstd: {
 193                 ZSTD_DCtx *ctx;
 194                 size_t real_src_len = le32_to_cpup(src_data.b);
 195
 196                 if (real_src_len > src_len - 4)
 197                         goto err;
 198
 199                 workspace = mempool_alloc(&c->decompress_workspace, GFP_NOIO);
 200                 ctx = ZSTD_initDCtx(workspace, ZSTD_DCtxWorkspaceBound());
 201
 202                 ret = ZSTD_decompressDCtx(ctx,
 203                                 dst_data,       dst_len,
 204                                 src_data.b + 4, real_src_len);
 205
 206                 mempool_free(workspace, &c->decompress_workspace);
 207
 208                 if (ret != dst_len)
 209                         goto err;
 210                 break;
 211         }
 212         default:
 213                 BUG();
 214         }
 215         ret = 0;
 216 out:
 217         bio_unmap_or_unbounce(c, src_data);
 218         return ret;
 219 err:
 220         ret = -EIO;
 221         goto out;
 222 }
 223
 224 int bch2_bio_uncompress_inplace(struct bch_fs *c, struct bio *bio,
 225                                 struct bch_extent_crc_unpacked *crc)
 226 {
 227         struct bbuf data = { NULL };
 228         size_t dst_len = crc->uncompressed_size << 9;
 229
 230         /* bio must own its pages: */
 231         BUG_ON(!bio->bi_vcnt);
 232         BUG_ON(DIV_ROUND_UP(crc->live_size, PAGE_SECTORS) > bio->bi_max_vecs);
 233
 234         if (crc->uncompressed_size      > c->sb.encoded_extent_max ||
 235             crc->compressed_size        > c->sb.encoded_extent_max) {
 236                 bch_err(c, "error rewriting existing data: extent too big");
 237                 return -EIO;
 238         }
 239
 240         data = __bounce_alloc(c, dst_len, WRITE);
 241
 242         if (__bio_uncompress(c, bio, data.b, *crc)) {
 243                 bch_err(c, "error rewriting existing data: decompression error");
 244                 bio_unmap_or_unbounce(c, data);
 245                 return -EIO;
 246         }
 247
 248         /*
 249          * XXX: don't have a good way to assert that the bio was allocated with
 250          * enough space, we depend on bch2_move_extent doing the right thing
 251          */
 252         bio->bi_iter.bi_size = crc->live_size << 9;
 253
 254         memcpy_to_bio(bio, bio->bi_iter, data.b + (crc->offset << 9));
 255
 256         crc->csum_type          = 0;
 257         crc->compression_type   = 0;
 258         crc->compressed_size    = crc->live_size;
 259         crc->uncompressed_size  = crc->live_size;
 260         crc->offset             = 0;
 261         crc->csum               = (struct bch_csum) { 0, 0 };
 262
 263         bio_unmap_or_unbounce(c, data);
 264         return 0;
 265 }
 266
 267 int bch2_bio_uncompress(struct bch_fs *c, struct bio *src,
 268                        struct bio *dst, struct bvec_iter dst_iter,
 269                        struct bch_extent_crc_unpacked crc)
 270 {
 271         struct bbuf dst_data = { NULL };
 272         size_t dst_len = crc.uncompressed_size << 9;
 273         int ret = -ENOMEM;
 274
 275         if (crc.uncompressed_size       > c->sb.encoded_extent_max ||
 276             crc.compressed_size         > c->sb.encoded_extent_max)
 277                 return -EIO;
 278
 279         dst_data = dst_len == dst_iter.bi_size
 280                 ? __bio_map_or_bounce(c, dst, dst_iter, WRITE)
 281                 : __bounce_alloc(c, dst_len, WRITE);
 282
 283         ret = __bio_uncompress(c, src, dst_data.b, crc);
 284         if (ret)
 285                 goto err;
 286
 287         if (dst_data.type != BB_NONE &&
 288             dst_data.type != BB_VMAP)
 289                 memcpy_to_bio(dst, dst_iter, dst_data.b + (crc.offset << 9));
 290 err:
 291         bio_unmap_or_unbounce(c, dst_data);
 292         return ret;
 293 }
 294
 295 static int attempt_compress(struct bch_fs *c,
 296                             void *workspace,
 297                             void *dst, size_t dst_len,
 298                             void *src, size_t src_len,
 299                             enum bch_compression_type compression_type)
 300 {
 301         switch (compression_type) {
 302         case BCH_COMPRESSION_TYPE_lz4: {
 303                 int len = src_len;
 304                 int ret = LZ4_compress_destSize(
 305                                 src,            dst,
 306                                 &len,           dst_len,
 307                                 workspace);
 308
 309                 if (len < src_len)
 310                         return -len;
 311
 312                 return ret;
 313         }
 314         case BCH_COMPRESSION_TYPE_gzip: {
 315                 z_stream strm = {
 316                         .next_in        = src,
 317                         .avail_in       = src_len,
 318                         .next_out       = dst,
 319                         .avail_out      = dst_len,
 320                 };
 321
 322                 zlib_set_workspace(&strm, workspace);
 323                 zlib_deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
 324                                   Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL,
 325                                   Z_DEFAULT_STRATEGY);
 326
 327                 if (zlib_deflate(&strm, Z_FINISH) != Z_STREAM_END)
 328                         return 0;
 329
 330                 if (zlib_deflateEnd(&strm) != Z_OK)
 331                         return 0;
 332
 333                 return strm.total_out;
 334         }
 335         case BCH_COMPRESSION_TYPE_zstd: {
 336                 ZSTD_CCtx *ctx = ZSTD_initCCtx(workspace,
 337                         ZSTD_CCtxWorkspaceBound(c->zstd_params.cParams));
 338
 339                 size_t len = ZSTD_compressCCtx(ctx,
 340                                 dst + 4,        dst_len - 4,
 341                                 src,            src_len,
 342                                 c->zstd_params);
 343                 if (ZSTD_isError(len))
 344                         return 0;
 345
 346                 *((__le32 *) dst) = cpu_to_le32(len);
 347                 return len + 4;
 348         }
 349         default:
 350                 BUG();
 351         }
 352 }
 353
 354 static unsigned __bio_compress(struct bch_fs *c,
 355                                struct bio *dst, size_t *dst_len,
 356                                struct bio *src, size_t *src_len,
 357                                enum bch_compression_type compression_type)
 358 {
 359         struct bbuf src_data = { NULL }, dst_data = { NULL };
 360         void *workspace;
 361         unsigned pad;
 362         int ret = 0;
 363
 364         BUG_ON(compression_type >= BCH_COMPRESSION_TYPE_NR);
 365         BUG_ON(!mempool_initialized(&c->compress_workspace[compression_type]));
 366
 367         /* If it's only one block, don't bother trying to compress: */
 368         if (bio_sectors(src) <= c->opts.block_size)
 369                 return 0;
 370
 371         dst_data = bio_map_or_bounce(c, dst, WRITE);
 372         src_data = bio_map_or_bounce(c, src, READ);
 373
 374         workspace = mempool_alloc(&c->compress_workspace[compression_type], GFP_NOIO);
 375
 376         *src_len = src->bi_iter.bi_size;
 377         *dst_len = dst->bi_iter.bi_size;
 378
 379         /*
 380          * XXX: this algorithm sucks when the compression code doesn't tell us
 381          * how much would fit, like LZ4 does:
 382          */
 383         while (1) {
 384                 if (*src_len <= block_bytes(c)) {
 385                         ret = -1;
 386                         break;
 387                 }
 388
 389                 ret = attempt_compress(c, workspace,
 390                                        dst_data.b,      *dst_len,
 391                                        src_data.b,      *src_len,
 392                                        compression_type);
 393                 if (ret > 0) {
 394                         *dst_len = ret;
 395                         ret = 0;
 396                         break;
 397                 }
 398
 399                 /* Didn't fit: should we retry with a smaller amount?  */
 400                 if (*src_len <= *dst_len) {
 401                         ret = -1;
 402                         break;
 403                 }
 404
 405                 /*
 406                  * If ret is negative, it's a hint as to how much data would fit
 407                  */
 408                 BUG_ON(-ret >= *src_len);
 409
 410                 if (ret < 0)
 411                         *src_len = -ret;
 412                 else
 413                         *src_len -= (*src_len - *dst_len) / 2;
 414                 *src_len = round_down(*src_len, block_bytes(c));
 415         }
 416
 417         mempool_free(workspace, &c->compress_workspace[compression_type]);
 418
 419         if (ret)
 420                 goto err;
 421
 422         /* Didn't get smaller: */
 423         if (round_up(*dst_len, block_bytes(c)) >= *src_len)
 424                 goto err;
 425
 426         pad = round_up(*dst_len, block_bytes(c)) - *dst_len;
 427
 428         memset(dst_data.b + *dst_len, 0, pad);
 429         *dst_len += pad;
 430
 431         if (dst_data.type != BB_NONE &&
 432             dst_data.type != BB_VMAP)
 433                 memcpy_to_bio(dst, dst->bi_iter, dst_data.b);
 434
 435         BUG_ON(!*dst_len || *dst_len > dst->bi_iter.bi_size);
 436         BUG_ON(!*src_len || *src_len > src->bi_iter.bi_size);
 437         BUG_ON(*dst_len & (block_bytes(c) - 1));
 438         BUG_ON(*src_len & (block_bytes(c) - 1));
 439 out:
 440         bio_unmap_or_unbounce(c, src_data);
 441         bio_unmap_or_unbounce(c, dst_data);
 442         return compression_type;
 443 err:
 444         compression_type = BCH_COMPRESSION_TYPE_incompressible;
 445         goto out;
 446 }
 447
 448 unsigned bch2_bio_compress(struct bch_fs *c,
 449                            struct bio *dst, size_t *dst_len,
 450                            struct bio *src, size_t *src_len,
 451                            unsigned compression_type)
 452 {
 453         unsigned orig_dst = dst->bi_iter.bi_size;
 454         unsigned orig_src = src->bi_iter.bi_size;
 455
 456         /* Don't consume more than BCH_ENCODED_EXTENT_MAX from @src: */
 457         src->bi_iter.bi_size = min_t(unsigned, src->bi_iter.bi_size,
 458                                      c->sb.encoded_extent_max << 9);
 459         /* Don't generate a bigger output than input: */
 460         dst->bi_iter.bi_size = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 461
 462         if (compression_type == BCH_COMPRESSION_TYPE_lz4_old)
 463                 compression_type = BCH_COMPRESSION_TYPE_lz4;
 464
 465         compression_type =
 466                 __bio_compress(c, dst, dst_len, src, src_len, compression_type);
 467
 468         dst->bi_iter.bi_size = orig_dst;
 469         src->bi_iter.bi_size = orig_src;
 470         return compression_type;
 471 }
 472
 473 static int __bch2_fs_compress_init(struct bch_fs *, u64);
 474
 475 #define BCH_FEATURE_none        0
 476
 477 static const unsigned bch2_compression_opt_to_feature[] = {
 478 #define x(t, n) [BCH_COMPRESSION_OPT_##t] = BCH_FEATURE_##t,
 479         BCH_COMPRESSION_OPTS()
 480 #undef x
 481 };
 482
 483 #undef BCH_FEATURE_none
 484
 485 static int __bch2_check_set_has_compressed_data(struct bch_fs *c, u64 f)
 486 {
 487         int ret = 0;
 488
 489         if ((c->sb.features & f) == f)
 490                 return 0;
 491
 492         mutex_lock(&c->sb_lock);
 493
 494         if ((c->sb.features & f) == f) {
 495                 mutex_unlock(&c->sb_lock);
 496                 return 0;
 497         }
 498
 499         ret = __bch2_fs_compress_init(c, c->sb.features|f);
 500         if (ret) {
 501                 mutex_unlock(&c->sb_lock);
 502                 return ret;
 503         }
 504
 505         c->disk_sb.sb->features[0] |= cpu_to_le64(f);
 506         bch2_write_super(c);
 507         mutex_unlock(&c->sb_lock);
 508
 509         return 0;
 510 }
 511
 512 int bch2_check_set_has_compressed_data(struct bch_fs *c,
 513                                        unsigned compression_type)
 514 {
 515         BUG_ON(compression_type >= ARRAY_SIZE(bch2_compression_opt_to_feature));
 516
 517         return compression_type
 518                 ? __bch2_check_set_has_compressed_data(c,
 519                                 1ULL << bch2_compression_opt_to_feature[compression_type])
 520                 : 0;
 521 }
 522
 523 void bch2_fs_compress_exit(struct bch_fs *c)
 524 {
 525         unsigned i;
 526
 527         mempool_exit(&c->decompress_workspace);
 528         for (i = 0; i < ARRAY_SIZE(c->compress_workspace); i++)
 529                 mempool_exit(&c->compress_workspace[i]);
 530         mempool_exit(&c->compression_bounce[WRITE]);
 531         mempool_exit(&c->compression_bounce[READ]);
 532 }
 533
 534 static int __bch2_fs_compress_init(struct bch_fs *c, u64 features)
 535 {
 536         size_t max_extent = c->sb.encoded_extent_max << 9;
 537         size_t decompress_workspace_size = 0;
 538         bool decompress_workspace_needed;
 539         ZSTD_parameters params = ZSTD_getParams(0, max_extent, 0);
 540         struct {
 541                 unsigned        feature;
 542                 unsigned        type;
 543                 size_t          compress_workspace;
 544                 size_t          decompress_workspace;
 545         } compression_types[] = {
 546                 { BCH_FEATURE_lz4, BCH_COMPRESSION_TYPE_lz4, LZ4_MEM_COMPRESS, 0 },
 547                 { BCH_FEATURE_gzip, BCH_COMPRESSION_TYPE_gzip,
 548                         zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL),
 549                         zlib_inflate_workspacesize(), },
 550                 { BCH_FEATURE_zstd, BCH_COMPRESSION_TYPE_zstd,
 551                         ZSTD_CCtxWorkspaceBound(params.cParams),
 552                         ZSTD_DCtxWorkspaceBound() },
 553         }, *i;
 554         int ret = 0;
 555
 556         pr_verbose_init(c->opts, "");
 557
 558         c->zstd_params = params;
 559
 560         for (i = compression_types;
 561              i < compression_types + ARRAY_SIZE(compression_types);
 562              i++)
 563                 if (features & (1 << i->feature))
 564                         goto have_compressed;
 565
 566         goto out;
 567 have_compressed:
 568
 569         if (!mempool_initialized(&c->compression_bounce[READ])) {
 570                 ret = mempool_init_kvpmalloc_pool(&c->compression_bounce[READ],
 571                                                   1, max_extent);
 572                 if (ret)
 573                         goto out;
 574         }
 575
 576         if (!mempool_initialized(&c->compression_bounce[WRITE])) {
 577                 ret = mempool_init_kvpmalloc_pool(&c->compression_bounce[WRITE],
 578                                                   1, max_extent);
 579                 if (ret)
 580                         goto out;
 581         }
 582
 583         for (i = compression_types;
 584              i < compression_types + ARRAY_SIZE(compression_types);
 585              i++) {
 586                 decompress_workspace_size =
 587                         max(decompress_workspace_size, i->decompress_workspace);
 588
 589                 if (!(features & (1 << i->feature)))
 590                         continue;
 591
 592                 if (i->decompress_workspace)
 593                         decompress_workspace_needed = true;
 594
 595                 if (mempool_initialized(&c->compress_workspace[i->type]))
 596                         continue;
 597
 598                 ret = mempool_init_kvpmalloc_pool(
 599                                 &c->compress_workspace[i->type],
 600                                 1, i->compress_workspace);
 601                 if (ret)
 602                         goto out;
 603         }
 604
 605         if (!mempool_initialized(&c->decompress_workspace)) {
 606                 ret = mempool_init_kvpmalloc_pool(
 607                                 &c->decompress_workspace,
 608                                 1, decompress_workspace_size);
 609                 if (ret)
 610                         goto out;
 611         }
 612 out:
 613         pr_verbose_init(c->opts, "ret %i", ret);
 614         return ret;
 615 }
 616
 617 int bch2_fs_compress_init(struct bch_fs *c)
 618 {
 619         u64 f = c->sb.features;
 620
 621         if (c->opts.compression)
 622                 f |= 1ULL << bch2_compression_opt_to_feature[c->opts.compression];
 623
 624         if (c->opts.background_compression)
 625                 f |= 1ULL << bch2_compression_opt_to_feature[c->opts.background_compression];
 626
 627         return __bch2_fs_compress_init(c, f);
 628
 629 }