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->opts.encoded_extent_max);
  30
  31         b = kmalloc(size, GFP_NOFS|__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_NOFS);
  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(start.bi_size > c->opts.encoded_extent_max);
  72
  73         if (!PageHighMem(bio_iter_page(bio, start)) &&
  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_NOFS)
  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_NOFS);
 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_NOFS);
 200                 ctx = zstd_init_dctx(workspace, zstd_dctx_workspace_bound());
 201
 202                 ret = zstd_decompress_dctx(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 << 9 > c->opts.encoded_extent_max ||
 235             crc->compressed_size << 9   > c->opts.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;
 274
 275         if (crc.uncompressed_size << 9  > c->opts.encoded_extent_max ||
 276             crc.compressed_size << 9    > c->opts.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_init_cctx(workspace,
 337                         zstd_cctx_workspace_bound(&c->zstd_params.cParams));
 338
 339                 /*
 340                  * ZSTD requires that when we decompress we pass in the exact
 341                  * compressed size - rounding it up to the nearest sector
 342                  * doesn't work, so we use the first 4 bytes of the buffer for
 343                  * that.
 344                  *
 345                  * Additionally, the ZSTD code seems to have a bug where it will
 346                  * write just past the end of the buffer - so subtract a fudge
 347                  * factor (7 bytes) from the dst buffer size to account for
 348                  * that.
 349                  */
 350                 size_t len = zstd_compress_cctx(ctx,
 351                                 dst + 4,        dst_len - 4 - 7,
 352                                 src,            src_len,
 353                                 &c->zstd_params);
 354                 if (zstd_is_error(len))
 355                         return 0;
 356
 357                 *((__le32 *) dst) = cpu_to_le32(len);
 358                 return len + 4;
 359         }
 360         default:
 361                 BUG();
 362         }
 363 }
 364
 365 static unsigned __bio_compress(struct bch_fs *c,
 366                                struct bio *dst, size_t *dst_len,
 367                                struct bio *src, size_t *src_len,
 368                                enum bch_compression_type compression_type)
 369 {
 370         struct bbuf src_data = { NULL }, dst_data = { NULL };
 371         void *workspace;
 372         unsigned pad;
 373         int ret = 0;
 374
 375         BUG_ON(compression_type >= BCH_COMPRESSION_TYPE_NR);
 376         BUG_ON(!mempool_initialized(&c->compress_workspace[compression_type]));
 377
 378         /* If it's only one block, don't bother trying to compress: */
 379         if (src->bi_iter.bi_size <= c->opts.block_size)
 380                 return BCH_COMPRESSION_TYPE_incompressible;
 381
 382         dst_data = bio_map_or_bounce(c, dst, WRITE);
 383         src_data = bio_map_or_bounce(c, src, READ);
 384
 385         workspace = mempool_alloc(&c->compress_workspace[compression_type], GFP_NOFS);
 386
 387         *src_len = src->bi_iter.bi_size;
 388         *dst_len = dst->bi_iter.bi_size;
 389
 390         /*
 391          * XXX: this algorithm sucks when the compression code doesn't tell us
 392          * how much would fit, like LZ4 does:
 393          */
 394         while (1) {
 395                 if (*src_len <= block_bytes(c)) {
 396                         ret = -1;
 397                         break;
 398                 }
 399
 400                 ret = attempt_compress(c, workspace,
 401                                        dst_data.b,      *dst_len,
 402                                        src_data.b,      *src_len,
 403                                        compression_type);
 404                 if (ret > 0) {
 405                         *dst_len = ret;
 406                         ret = 0;
 407                         break;
 408                 }
 409
 410                 /* Didn't fit: should we retry with a smaller amount?  */
 411                 if (*src_len <= *dst_len) {
 412                         ret = -1;
 413                         break;
 414                 }
 415
 416                 /*
 417                  * If ret is negative, it's a hint as to how much data would fit
 418                  */
 419                 BUG_ON(-ret >= *src_len);
 420
 421                 if (ret < 0)
 422                         *src_len = -ret;
 423                 else
 424                         *src_len -= (*src_len - *dst_len) / 2;
 425                 *src_len = round_down(*src_len, block_bytes(c));
 426         }
 427
 428         mempool_free(workspace, &c->compress_workspace[compression_type]);
 429
 430         if (ret)
 431                 goto err;
 432
 433         /* Didn't get smaller: */
 434         if (round_up(*dst_len, block_bytes(c)) >= *src_len)
 435                 goto err;
 436
 437         pad = round_up(*dst_len, block_bytes(c)) - *dst_len;
 438
 439         memset(dst_data.b + *dst_len, 0, pad);
 440         *dst_len += pad;
 441
 442         if (dst_data.type != BB_NONE &&
 443             dst_data.type != BB_VMAP)
 444                 memcpy_to_bio(dst, dst->bi_iter, dst_data.b);
 445
 446         BUG_ON(!*dst_len || *dst_len > dst->bi_iter.bi_size);
 447         BUG_ON(!*src_len || *src_len > src->bi_iter.bi_size);
 448         BUG_ON(*dst_len & (block_bytes(c) - 1));
 449         BUG_ON(*src_len & (block_bytes(c) - 1));
 450 out:
 451         bio_unmap_or_unbounce(c, src_data);
 452         bio_unmap_or_unbounce(c, dst_data);
 453         return compression_type;
 454 err:
 455         compression_type = BCH_COMPRESSION_TYPE_incompressible;
 456         goto out;
 457 }
 458
 459 unsigned bch2_bio_compress(struct bch_fs *c,
 460                            struct bio *dst, size_t *dst_len,
 461                            struct bio *src, size_t *src_len,
 462                            unsigned compression_type)
 463 {
 464         unsigned orig_dst = dst->bi_iter.bi_size;
 465         unsigned orig_src = src->bi_iter.bi_size;
 466
 467         /* Don't consume more than BCH_ENCODED_EXTENT_MAX from @src: */
 468         src->bi_iter.bi_size = min_t(unsigned, src->bi_iter.bi_size,
 469                                      c->opts.encoded_extent_max);
 470         /* Don't generate a bigger output than input: */
 471         dst->bi_iter.bi_size = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 472
 473         if (compression_type == BCH_COMPRESSION_TYPE_lz4_old)
 474                 compression_type = BCH_COMPRESSION_TYPE_lz4;
 475
 476         compression_type =
 477                 __bio_compress(c, dst, dst_len, src, src_len, compression_type);
 478
 479         dst->bi_iter.bi_size = orig_dst;
 480         src->bi_iter.bi_size = orig_src;
 481         return compression_type;
 482 }
 483
 484 static int __bch2_fs_compress_init(struct bch_fs *, u64);
 485
 486 #define BCH_FEATURE_none        0
 487
 488 static const unsigned bch2_compression_opt_to_feature[] = {
 489 #define x(t, n) [BCH_COMPRESSION_OPT_##t] = BCH_FEATURE_##t,
 490         BCH_COMPRESSION_OPTS()
 491 #undef x
 492 };
 493
 494 #undef BCH_FEATURE_none
 495
 496 static int __bch2_check_set_has_compressed_data(struct bch_fs *c, u64 f)
 497 {
 498         int ret = 0;
 499
 500         if ((c->sb.features & f) == f)
 501                 return 0;
 502
 503         mutex_lock(&c->sb_lock);
 504
 505         if ((c->sb.features & f) == f) {
 506                 mutex_unlock(&c->sb_lock);
 507                 return 0;
 508         }
 509
 510         ret = __bch2_fs_compress_init(c, c->sb.features|f);
 511         if (ret) {
 512                 mutex_unlock(&c->sb_lock);
 513                 return ret;
 514         }
 515
 516         c->disk_sb.sb->features[0] |= cpu_to_le64(f);
 517         bch2_write_super(c);
 518         mutex_unlock(&c->sb_lock);
 519
 520         return 0;
 521 }
 522
 523 int bch2_check_set_has_compressed_data(struct bch_fs *c,
 524                                        unsigned compression_type)
 525 {
 526         BUG_ON(compression_type >= ARRAY_SIZE(bch2_compression_opt_to_feature));
 527
 528         return compression_type
 529                 ? __bch2_check_set_has_compressed_data(c,
 530                                 1ULL << bch2_compression_opt_to_feature[compression_type])
 531                 : 0;
 532 }
 533
 534 void bch2_fs_compress_exit(struct bch_fs *c)
 535 {
 536         unsigned i;
 537
 538         mempool_exit(&c->decompress_workspace);
 539         for (i = 0; i < ARRAY_SIZE(c->compress_workspace); i++)
 540                 mempool_exit(&c->compress_workspace[i]);
 541         mempool_exit(&c->compression_bounce[WRITE]);
 542         mempool_exit(&c->compression_bounce[READ]);
 543 }
 544
 545 static int _bch2_fs_compress_init(struct bch_fs *c, u64 features)
 546 {
 547         size_t decompress_workspace_size = 0;
 548         bool decompress_workspace_needed;
 549         ZSTD_parameters params = zstd_get_params(0, c->opts.encoded_extent_max);
 550         struct {
 551                 unsigned        feature;
 552                 unsigned        type;
 553                 size_t          compress_workspace;
 554                 size_t          decompress_workspace;
 555         } compression_types[] = {
 556                 { BCH_FEATURE_lz4, BCH_COMPRESSION_TYPE_lz4, LZ4_MEM_COMPRESS, 0 },
 557                 { BCH_FEATURE_gzip, BCH_COMPRESSION_TYPE_gzip,
 558                         zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL),
 559                         zlib_inflate_workspacesize(), },
 560                 { BCH_FEATURE_zstd, BCH_COMPRESSION_TYPE_zstd,
 561                         zstd_cctx_workspace_bound(&params.cParams),
 562                         zstd_dctx_workspace_bound() },
 563         }, *i;
 564         bool have_compressed = false;
 565
 566         c->zstd_params = params;
 567
 568         for (i = compression_types;
 569              i < compression_types + ARRAY_SIZE(compression_types);
 570              i++)
 571                 have_compressed |= (features & (1 << i->feature)) != 0;
 572
 573         if (!have_compressed)
 574                 return 0;
 575
 576         if (!mempool_initialized(&c->compression_bounce[READ]) &&
 577             mempool_init_kvpmalloc_pool(&c->compression_bounce[READ],
 578                                         1, c->opts.encoded_extent_max))
 579                 return -BCH_ERR_ENOMEM_compression_bounce_read_init;
 580
 581         if (!mempool_initialized(&c->compression_bounce[WRITE]) &&
 582             mempool_init_kvpmalloc_pool(&c->compression_bounce[WRITE],
 583                                         1, c->opts.encoded_extent_max))
 584                 return -BCH_ERR_ENOMEM_compression_bounce_write_init;
 585
 586         for (i = compression_types;
 587              i < compression_types + ARRAY_SIZE(compression_types);
 588              i++) {
 589                 decompress_workspace_size =
 590                         max(decompress_workspace_size, i->decompress_workspace);
 591
 592                 if (!(features & (1 << i->feature)))
 593                         continue;
 594
 595                 if (i->decompress_workspace)
 596                         decompress_workspace_needed = true;
 597
 598                 if (mempool_initialized(&c->compress_workspace[i->type]))
 599                         continue;
 600
 601                 if (mempool_init_kvpmalloc_pool(
 602                                 &c->compress_workspace[i->type],
 603                                 1, i->compress_workspace))
 604                         return -BCH_ERR_ENOMEM_compression_workspace_init;
 605         }
 606
 607         if (!mempool_initialized(&c->decompress_workspace) &&
 608             mempool_init_kvpmalloc_pool(&c->decompress_workspace,
 609                                         1, decompress_workspace_size))
 610                 return -BCH_ERR_ENOMEM_decompression_workspace_init;
 611
 612         return 0;
 613 }
 614
 615 static int __bch2_fs_compress_init(struct bch_fs *c, u64 features)
 616 {
 617         int ret;
 618
 619         pr_verbose_init(c->opts, "");
 620         ret = _bch2_fs_compress_init(c, features);
 621         pr_verbose_init(c->opts, "ret %i", ret);
 622
 623         return ret;
 624 }
 625
 626 int bch2_fs_compress_init(struct bch_fs *c)
 627 {
 628         u64 f = c->sb.features;
 629
 630         if (c->opts.compression)
 631                 f |= 1ULL << bch2_compression_opt_to_feature[c->opts.compression];
 632
 633         if (c->opts.background_compression)
 634                 f |= 1ULL << bch2_compression_opt_to_feature[c->opts.background_compression];
 635
 636         return __bch2_fs_compress_init(c, f);
 637
 638 }