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

   1 #include "bcachefs.h"
   2 #include "checksum.h"
   3 #include "compress.h"
   4 #include "extents.h"
   5 #include "io.h"
   6 #include "super-io.h"
   7
   8 #include "lz4.h"
   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_VMALLOC,
  21                 BB_MEMPOOL,
  22         }               type;
  23         int             rw;
  24 };
  25
  26 static struct bbuf __bounce_alloc(struct bch_fs *c, unsigned size, int rw)
  27 {
  28         void *b;
  29
  30         BUG_ON(size > c->sb.encoded_extent_max << 9);
  31
  32         b = kmalloc(size, GFP_NOIO|__GFP_NOWARN);
  33         if (b)
  34                 return (struct bbuf) { .b = b, .type = BB_KMALLOC, .rw = rw };
  35
  36         b = mempool_alloc(&c->compression_bounce[rw], GFP_NOWAIT);
  37         b = b ? page_address(b) : NULL;
  38         if (b)
  39                 return (struct bbuf) { .b = b, .type = BB_MEMPOOL, .rw = rw };
  40
  41         b = vmalloc(size);
  42         if (b)
  43                 return (struct bbuf) { .b = b, .type = BB_VMALLOC, .rw = rw };
  44
  45         b = mempool_alloc(&c->compression_bounce[rw], GFP_NOIO);
  46         b = b ? page_address(b) : NULL;
  47         if (b)
  48                 return (struct bbuf) { .b = b, .type = BB_MEMPOOL, .rw = rw };
  49
  50         BUG();
  51 }
  52
  53 static struct bbuf __bio_map_or_bounce(struct bch_fs *c, struct bio *bio,
  54                                        struct bvec_iter start, int rw)
  55 {
  56         struct bbuf ret;
  57         struct bio_vec bv;
  58         struct bvec_iter iter;
  59         unsigned nr_pages = 0;
  60         struct page *stack_pages[16];
  61         struct page **pages = NULL;
  62         bool first = true;
  63         unsigned prev_end = PAGE_SIZE;
  64         void *data;
  65
  66         BUG_ON(bvec_iter_sectors(start) > c->sb.encoded_extent_max);
  67
  68 #ifndef CONFIG_HIGHMEM
  69         __bio_for_each_contig_segment(bv, bio, iter, start) {
  70                 if (bv.bv_len == start.bi_size)
  71                         return (struct bbuf) {
  72                                 .b = page_address(bv.bv_page) + bv.bv_offset,
  73                                 .type = BB_NONE, .rw = rw
  74                         };
  75         }
  76 #endif
  77         __bio_for_each_segment(bv, bio, iter, start) {
  78                 if ((!first && bv.bv_offset) ||
  79                     prev_end != PAGE_SIZE)
  80                         goto bounce;
  81
  82                 prev_end = bv.bv_offset + bv.bv_len;
  83                 nr_pages++;
  84         }
  85
  86         BUG_ON(DIV_ROUND_UP(start.bi_size, PAGE_SIZE) > nr_pages);
  87
  88         pages = nr_pages > ARRAY_SIZE(stack_pages)
  89                 ? kmalloc_array(nr_pages, sizeof(struct page *), GFP_NOIO)
  90                 : stack_pages;
  91         if (!pages)
  92                 goto bounce;
  93
  94         nr_pages = 0;
  95         __bio_for_each_segment(bv, bio, iter, start)
  96                 pages[nr_pages++] = bv.bv_page;
  97
  98         data = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
  99         if (pages != stack_pages)
 100                 kfree(pages);
 101
 102         if (data)
 103                 return (struct bbuf) {
 104                         .b = data + bio_iter_offset(bio, start),
 105                         .type = BB_VMAP, .rw = rw
 106                 };
 107 bounce:
 108         ret = __bounce_alloc(c, start.bi_size, rw);
 109
 110         if (rw == READ)
 111                 memcpy_from_bio(ret.b, bio, start);
 112
 113         return ret;
 114 }
 115
 116 static struct bbuf bio_map_or_bounce(struct bch_fs *c, struct bio *bio, int rw)
 117 {
 118         return __bio_map_or_bounce(c, bio, bio->bi_iter, rw);
 119 }
 120
 121 static void bio_unmap_or_unbounce(struct bch_fs *c, struct bbuf buf)
 122 {
 123         switch (buf.type) {
 124         case BB_NONE:
 125                 break;
 126         case BB_VMAP:
 127                 vunmap((void *) ((unsigned long) buf.b & PAGE_MASK));
 128                 break;
 129         case BB_KMALLOC:
 130                 kfree(buf.b);
 131                 break;
 132         case BB_VMALLOC:
 133                 vfree(buf.b);
 134                 break;
 135         case BB_MEMPOOL:
 136                 mempool_free(virt_to_page(buf.b),
 137                              &c->compression_bounce[buf.rw]);
 138                 break;
 139         }
 140 }
 141
 142 static inline void zlib_set_workspace(z_stream *strm, void *workspace)
 143 {
 144 #ifdef __KERNEL__
 145         strm->workspace = workspace;
 146 #endif
 147 }
 148
 149 static int __bio_uncompress(struct bch_fs *c, struct bio *src,
 150                             void *dst_data, struct bch_extent_crc_unpacked crc)
 151 {
 152         struct bbuf src_data = { NULL };
 153         size_t src_len = src->bi_iter.bi_size;
 154         size_t dst_len = crc.uncompressed_size << 9;
 155         void *workspace;
 156         int ret;
 157
 158         src_data = bio_map_or_bounce(c, src, READ);
 159
 160         switch (crc.compression_type) {
 161         case BCH_COMPRESSION_LZ4_OLD:
 162                 ret = bch2_lz4_decompress(src_data.b, &src_len,
 163                                      dst_data, dst_len);
 164                 if (ret)
 165                         goto err;
 166                 break;
 167         case BCH_COMPRESSION_LZ4:
 168                 ret = LZ4_decompress_safe_partial(src_data.b, dst_data,
 169                                                   src_len, dst_len, dst_len);
 170                 if (ret != dst_len)
 171                         goto err;
 172                 break;
 173         case BCH_COMPRESSION_GZIP: {
 174                 z_stream strm = {
 175                         .next_in        = src_data.b,
 176                         .avail_in       = src_len,
 177                         .next_out       = dst_data,
 178                         .avail_out      = dst_len,
 179                 };
 180
 181                 workspace = mempool_alloc(&c->decompress_workspace, GFP_NOIO);
 182
 183                 zlib_set_workspace(&strm, workspace);
 184                 zlib_inflateInit2(&strm, -MAX_WBITS);
 185                 ret = zlib_inflate(&strm, Z_FINISH);
 186
 187                 mempool_free(workspace, &c->decompress_workspace);
 188
 189                 if (ret != Z_STREAM_END)
 190                         goto err;
 191                 break;
 192         }
 193         case BCH_COMPRESSION_ZSTD: {
 194                 ZSTD_DCtx *ctx;
 195                 size_t len;
 196
 197                 workspace = mempool_alloc(&c->decompress_workspace, GFP_NOIO);
 198                 ctx = ZSTD_initDCtx(workspace, ZSTD_DCtxWorkspaceBound());
 199
 200                 src_len = le32_to_cpup(src_data.b);
 201
 202                 len = ZSTD_decompressDCtx(ctx,
 203                                 dst_data,       dst_len,
 204                                 src_data.b + 4, src_len);
 205
 206                 mempool_free(workspace, &c->decompress_workspace);
 207
 208                 if (len != 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          * might have to free existing pages and retry allocation from mempool -
 250          * do this _after_ decompressing:
 251          */
 252         bch2_bio_alloc_more_pages_pool(c, bio, 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                 memcpy_to_bio(dst, dst_iter, dst_data.b + (crc.offset << 9));
 289 err:
 290         bio_unmap_or_unbounce(c, dst_data);
 291         return ret;
 292 }
 293
 294 static int attempt_compress(struct bch_fs *c,
 295                             void *workspace,
 296                             void *dst, size_t dst_len,
 297                             void *src, size_t src_len,
 298                             unsigned compression_type)
 299 {
 300         switch (compression_type) {
 301         case BCH_COMPRESSION_LZ4: {
 302                 int len = src_len;
 303                 int ret = LZ4_compress_destSize(
 304                                 src,            dst,
 305                                 &len,           dst_len,
 306                                 workspace);
 307
 308                 if (len < src_len)
 309                         return -len;
 310
 311                 return ret;
 312         }
 313         case BCH_COMPRESSION_GZIP: {
 314                 z_stream strm = {
 315                         .next_in        = src,
 316                         .avail_in       = src_len,
 317                         .next_out       = dst,
 318                         .avail_out      = dst_len,
 319                 };
 320
 321                 zlib_set_workspace(&strm, workspace);
 322                 zlib_deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
 323                                   Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL,
 324                                   Z_DEFAULT_STRATEGY);
 325
 326                 if (zlib_deflate(&strm, Z_FINISH) != Z_STREAM_END)
 327                         return 0;
 328
 329                 if (zlib_deflateEnd(&strm) != Z_OK)
 330                         return 0;
 331
 332                 return strm.total_out;
 333         }
 334         case BCH_COMPRESSION_ZSTD: {
 335                 ZSTD_CCtx *ctx = ZSTD_initCCtx(workspace,
 336                         ZSTD_CCtxWorkspaceBound(c->zstd_params.cParams));
 337
 338                 size_t len = ZSTD_compressCCtx(ctx,
 339                                 dst + 4,        dst_len - 4,
 340                                 src,            src_len,
 341                                 c->zstd_params);
 342                 if (ZSTD_isError(len))
 343                         return 0;
 344
 345                 *((__le32 *) dst) = cpu_to_le32(len);
 346                 return len + 4;
 347         }
 348         default:
 349                 BUG();
 350         }
 351 }
 352
 353 static unsigned __bio_compress(struct bch_fs *c,
 354                                struct bio *dst, size_t *dst_len,
 355                                struct bio *src, size_t *src_len,
 356                                unsigned compression_type)
 357 {
 358         struct bbuf src_data = { NULL }, dst_data = { NULL };
 359         void *workspace;
 360         unsigned pad;
 361         int ret = 0;
 362
 363         /* If it's only one block, don't bother trying to compress: */
 364         if (bio_sectors(src) <= c->opts.block_size)
 365                 return 0;
 366
 367         dst_data = bio_map_or_bounce(c, dst, WRITE);
 368         src_data = bio_map_or_bounce(c, src, READ);
 369
 370         workspace = mempool_alloc(&c->compress_workspace[compression_type], GFP_NOIO);
 371
 372         *src_len = src->bi_iter.bi_size;
 373         *dst_len = dst->bi_iter.bi_size;
 374
 375         /*
 376          * XXX: this algorithm sucks when the compression code doesn't tell us
 377          * how much would fit, like LZ4 does:
 378          */
 379         while (1) {
 380                 if (*src_len <= block_bytes(c)) {
 381                         ret = -1;
 382                         break;
 383                 }
 384
 385                 ret = attempt_compress(c, workspace,
 386                                        dst_data.b,      *dst_len,
 387                                        src_data.b,      *src_len,
 388                                        compression_type);
 389                 if (ret > 0) {
 390                         *dst_len = ret;
 391                         ret = 0;
 392                         break;
 393                 }
 394
 395                 /* Didn't fit: should we retry with a smaller amount?  */
 396                 if (*src_len <= *dst_len) {
 397                         ret = -1;
 398                         break;
 399                 }
 400
 401                 /*
 402                  * If ret is negative, it's a hint as to how much data would fit
 403                  */
 404                 BUG_ON(-ret >= *src_len);
 405
 406                 if (ret < 0)
 407                         *src_len = -ret;
 408                 else
 409                         *src_len -= (*src_len - *dst_len) / 2;
 410                 *src_len = round_down(*src_len, block_bytes(c));
 411         }
 412
 413         mempool_free(workspace, &c->compress_workspace[compression_type]);
 414
 415         if (ret)
 416                 goto err;
 417
 418         /* Didn't get smaller: */
 419         if (round_up(*dst_len, block_bytes(c)) >= *src_len)
 420                 goto err;
 421
 422         pad = round_up(*dst_len, block_bytes(c)) - *dst_len;
 423
 424         memset(dst_data.b + *dst_len, 0, pad);
 425         *dst_len += pad;
 426
 427         if (dst_data.type != BB_NONE)
 428                 memcpy_to_bio(dst, dst->bi_iter, dst_data.b);
 429
 430         BUG_ON(!*dst_len || *dst_len > dst->bi_iter.bi_size);
 431         BUG_ON(!*src_len || *src_len > src->bi_iter.bi_size);
 432         BUG_ON(*dst_len & (block_bytes(c) - 1));
 433         BUG_ON(*src_len & (block_bytes(c) - 1));
 434 out:
 435         bio_unmap_or_unbounce(c, src_data);
 436         bio_unmap_or_unbounce(c, dst_data);
 437         return compression_type;
 438 err:
 439         compression_type = 0;
 440         goto out;
 441 }
 442
 443 unsigned bch2_bio_compress(struct bch_fs *c,
 444                            struct bio *dst, size_t *dst_len,
 445                            struct bio *src, size_t *src_len,
 446                            unsigned compression_type)
 447 {
 448         unsigned orig_dst = dst->bi_iter.bi_size;
 449         unsigned orig_src = src->bi_iter.bi_size;
 450
 451         /* Don't consume more than BCH_ENCODED_EXTENT_MAX from @src: */
 452         src->bi_iter.bi_size = min_t(unsigned, src->bi_iter.bi_size,
 453                                      c->sb.encoded_extent_max << 9);
 454         /* Don't generate a bigger output than input: */
 455         dst->bi_iter.bi_size = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 456
 457         if (compression_type == BCH_COMPRESSION_LZ4_OLD)
 458                 compression_type = BCH_COMPRESSION_LZ4;
 459
 460         compression_type =
 461                 __bio_compress(c, dst, dst_len, src, src_len, compression_type);
 462
 463         dst->bi_iter.bi_size = orig_dst;
 464         src->bi_iter.bi_size = orig_src;
 465         return compression_type;
 466 }
 467
 468 #define BCH_FEATURE_NONE        0
 469
 470 static const unsigned bch2_compression_opt_to_feature[] = {
 471 #define x(t) [BCH_COMPRESSION_OPT_##t] = BCH_FEATURE_##t,
 472         BCH_COMPRESSION_TYPES()
 473 #undef x
 474 };
 475
 476 #undef BCH_FEATURE_NONE
 477
 478 /* doesn't write superblock: */
 479 int bch2_check_set_has_compressed_data(struct bch_fs *c,
 480                                       unsigned compression_type)
 481 {
 482         unsigned f;
 483         int ret = 0;
 484
 485         pr_verbose_init(c->opts, "");
 486
 487         BUG_ON(compression_type >= ARRAY_SIZE(bch2_compression_opt_to_feature));
 488
 489         if (!compression_type)
 490                 goto out;
 491
 492         f = bch2_compression_opt_to_feature[compression_type];
 493         if (bch2_sb_test_feature(c->disk_sb, f))
 494                 goto out;
 495
 496         bch2_sb_set_feature(c->disk_sb, f);
 497         ret = bch2_fs_compress_init(c);
 498 out:
 499         pr_verbose_init(c->opts, "ret %i", ret);
 500         return ret;
 501 }
 502
 503 void bch2_fs_compress_exit(struct bch_fs *c)
 504 {
 505         unsigned i;
 506
 507         mempool_exit(&c->decompress_workspace);
 508         for (i = 0; i < ARRAY_SIZE(c->compress_workspace); i++)
 509                 mempool_exit(&c->compress_workspace[i]);
 510         mempool_exit(&c->compression_bounce[WRITE]);
 511         mempool_exit(&c->compression_bounce[READ]);
 512 }
 513
 514 static void *mempool_kvpmalloc(gfp_t gfp_mask, void *pool_data)
 515 {
 516         size_t size = (size_t)pool_data;
 517         return kvpmalloc(size, gfp_mask);
 518 }
 519
 520 void mempool_kvpfree(void *element, void *pool_data)
 521 {
 522         size_t size = (size_t)pool_data;
 523         kvpfree(element, size);
 524 }
 525
 526 static int mempool_init_kvpmalloc_pool(mempool_t *pool, int min_nr, size_t size)
 527 {
 528         return !mempool_initialized(pool)
 529                 ? mempool_init(pool, min_nr, mempool_kvpmalloc,
 530                                mempool_kvpfree, (void *) size)
 531                 : 0;
 532 }
 533
 534 int bch2_fs_compress_init(struct bch_fs *c)
 535 {
 536         size_t max_extent = c->sb.encoded_extent_max << 9;
 537         size_t order = get_order(max_extent);
 538         size_t decompress_workspace_size = 0;
 539         bool decompress_workspace_needed;
 540         ZSTD_parameters params = ZSTD_getParams(0, max_extent, 0);
 541         struct {
 542                 unsigned        feature;
 543                 unsigned        type;
 544                 size_t          compress_workspace;
 545                 size_t          decompress_workspace;
 546         } compression_types[] = {
 547                 { BCH_FEATURE_LZ4, BCH_COMPRESSION_LZ4, LZ4_MEM_COMPRESS, 0 },
 548                 { BCH_FEATURE_GZIP, BCH_COMPRESSION_GZIP,
 549                         zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL),
 550                         zlib_inflate_workspacesize(), },
 551                 { BCH_FEATURE_ZSTD, BCH_COMPRESSION_ZSTD,
 552                         ZSTD_CCtxWorkspaceBound(params.cParams),
 553                         ZSTD_DCtxWorkspaceBound() },
 554         }, *i;
 555         int ret = 0;
 556
 557         pr_verbose_init(c->opts, "");
 558
 559         c->zstd_params = params;
 560
 561         for (i = compression_types;
 562              i < compression_types + ARRAY_SIZE(compression_types);
 563              i++)
 564                 if (bch2_sb_test_feature(c->disk_sb, i->feature))
 565                         goto have_compressed;
 566
 567         goto out;
 568 have_compressed:
 569
 570         if (!mempool_initialized(&c->compression_bounce[READ])) {
 571                 ret = mempool_init_page_pool(&c->compression_bounce[READ],
 572                                              1, order);
 573                 if (ret)
 574                         goto out;
 575         }
 576
 577         if (!mempool_initialized(&c->compression_bounce[WRITE])) {
 578                 ret = mempool_init_page_pool(&c->compression_bounce[WRITE],
 579                                              1, order);
 580                 if (ret)
 581                         goto out;
 582         }
 583
 584         for (i = compression_types;
 585              i < compression_types + ARRAY_SIZE(compression_types);
 586              i++) {
 587                 decompress_workspace_size =
 588                         max(decompress_workspace_size, i->decompress_workspace);
 589
 590                 if (!bch2_sb_test_feature(c->disk_sb, i->feature))
 591                         continue;
 592
 593                 if (i->decompress_workspace)
 594                         decompress_workspace_needed = true;
 595
 596                 ret = mempool_init_kvpmalloc_pool(
 597                                 &c->compress_workspace[i->type],
 598                                 1, i->compress_workspace);
 599                 if (ret)
 600                         goto out;
 601         }
 602
 603         ret = mempool_init_kmalloc_pool(
 604                         &c->decompress_workspace,
 605                         1, decompress_workspace_size);
 606         if (ret)
 607                 goto out;
 608 out:
 609         pr_verbose_init(c->opts, "ret %i", ret);
 610         return ret;
 611 }