fs/btrfs/zlib.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2008 Oracle.  All rights reserved.
   4  *
   5  * Based on jffs2 zlib code:
   6  * Copyright © 2001-2007 Red Hat, Inc.
   7  * Created by David Woodhouse <[email protected]>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/zlib.h>
  13 #include <linux/zutil.h>
  14 #include <linux/mm.h>
  15 #include <linux/init.h>
  16 #include <linux/err.h>
  17 #include <linux/sched.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/bio.h>
  20 #include <linux/refcount.h>
  21 #include "compression.h"
  22
  23 /* workspace buffer size for s390 zlib hardware support */
  24 #define ZLIB_DFLTCC_BUF_SIZE    (4 * PAGE_SIZE)
  25
  26 struct workspace {
  27         z_stream strm;
  28         char *buf;
  29         unsigned int buf_size;
  30         struct list_head list;
  31         int level;
  32 };
  33
  34 static struct workspace_manager wsm;
  35
  36 struct list_head *zlib_get_workspace(unsigned int level)
  37 {
  38         struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
  39         struct workspace *workspace = list_entry(ws, struct workspace, list);
  40
  41         workspace->level = level;
  42
  43         return ws;
  44 }
  45
  46 void zlib_free_workspace(struct list_head *ws)
  47 {
  48         struct workspace *workspace = list_entry(ws, struct workspace, list);
  49
  50         kvfree(workspace->strm.workspace);
  51         kfree(workspace->buf);
  52         kfree(workspace);
  53 }
  54
  55 struct list_head *zlib_alloc_workspace(unsigned int level)
  56 {
  57         struct workspace *workspace;
  58         int workspacesize;
  59
  60         workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
  61         if (!workspace)
  62                 return ERR_PTR(-ENOMEM);
  63
  64         workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
  65                         zlib_inflate_workspacesize());
  66         workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN);
  67         workspace->level = level;
  68         workspace->buf = NULL;
  69         /*
  70          * In case of s390 zlib hardware support, allocate lager workspace
  71          * buffer. If allocator fails, fall back to a single page buffer.
  72          */
  73         if (zlib_deflate_dfltcc_enabled()) {
  74                 workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
  75                                          __GFP_NOMEMALLOC | __GFP_NORETRY |
  76                                          __GFP_NOWARN | GFP_NOIO);
  77                 workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
  78         }
  79         if (!workspace->buf) {
  80                 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  81                 workspace->buf_size = PAGE_SIZE;
  82         }
  83         if (!workspace->strm.workspace || !workspace->buf)
  84                 goto fail;
  85
  86         INIT_LIST_HEAD(&workspace->list);
  87
  88         return &workspace->list;
  89 fail:
  90         zlib_free_workspace(&workspace->list);
  91         return ERR_PTR(-ENOMEM);
  92 }
  93
  94 int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
  95                          u64 start, struct folio **folios, unsigned long *out_folios,
  96                          unsigned long *total_in, unsigned long *total_out)
  97 {
  98         struct workspace *workspace = list_entry(ws, struct workspace, list);
  99         int ret;
 100         char *data_in = NULL;
 101         char *cfolio_out;
 102         int nr_folios = 0;
 103         struct folio *in_folio = NULL;
 104         struct folio *out_folio = NULL;
 105         unsigned long bytes_left;
 106         unsigned int in_buf_folios;
 107         unsigned long len = *total_out;
 108         unsigned long nr_dest_folios = *out_folios;
 109         const unsigned long max_out = nr_dest_folios * PAGE_SIZE;
 110
 111         *out_folios = 0;
 112         *total_out = 0;
 113         *total_in = 0;
 114
 115         if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
 116                 pr_warn("BTRFS: deflateInit failed\n");
 117                 ret = -EIO;
 118                 goto out;
 119         }
 120
 121         workspace->strm.total_in = 0;
 122         workspace->strm.total_out = 0;
 123
 124         out_folio = btrfs_alloc_compr_folio();
 125         if (out_folio == NULL) {
 126                 ret = -ENOMEM;
 127                 goto out;
 128         }
 129         cfolio_out = folio_address(out_folio);
 130         folios[0] = out_folio;
 131         nr_folios = 1;
 132
 133         workspace->strm.next_in = workspace->buf;
 134         workspace->strm.avail_in = 0;
 135         workspace->strm.next_out = cfolio_out;
 136         workspace->strm.avail_out = PAGE_SIZE;
 137
 138         while (workspace->strm.total_in < len) {
 139                 /*
 140                  * Get next input pages and copy the contents to
 141                  * the workspace buffer if required.
 142                  */
 143                 if (workspace->strm.avail_in == 0) {
 144                         bytes_left = len - workspace->strm.total_in;
 145                         in_buf_folios = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
 146                                             workspace->buf_size / PAGE_SIZE);
 147                         if (in_buf_folios > 1) {
 148                                 int i;
 149
 150                                 for (i = 0; i < in_buf_folios; i++) {
 151                                         if (data_in) {
 152                                                 kunmap_local(data_in);
 153                                                 folio_put(in_folio);
 154                                                 data_in = NULL;
 155                                         }
 156                                         ret = btrfs_compress_filemap_get_folio(mapping,
 157                                                         start, &in_folio);
 158                                         if (ret < 0)
 159                                                 goto out;
 160                                         data_in = kmap_local_folio(in_folio, 0);
 161                                         copy_page(workspace->buf + i * PAGE_SIZE,
 162                                                   data_in);
 163                                         start += PAGE_SIZE;
 164                                 }
 165                                 workspace->strm.next_in = workspace->buf;
 166                         } else {
 167                                 if (data_in) {
 168                                         kunmap_local(data_in);
 169                                         folio_put(in_folio);
 170                                         data_in = NULL;
 171                                 }
 172                                 ret = btrfs_compress_filemap_get_folio(mapping,
 173                                                 start, &in_folio);
 174                                 if (ret < 0)
 175                                         goto out;
 176                                 data_in = kmap_local_folio(in_folio, 0);
 177                                 start += PAGE_SIZE;
 178                                 workspace->strm.next_in = data_in;
 179                         }
 180                         workspace->strm.avail_in = min(bytes_left,
 181                                                        (unsigned long) workspace->buf_size);
 182                 }
 183
 184                 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
 185                 if (ret != Z_OK) {
 186                         pr_debug("BTRFS: deflate in loop returned %d\n",
 187                                ret);
 188                         zlib_deflateEnd(&workspace->strm);
 189                         ret = -EIO;
 190                         goto out;
 191                 }
 192
 193                 /* we're making it bigger, give up */
 194                 if (workspace->strm.total_in > 8192 &&
 195                     workspace->strm.total_in <
 196                     workspace->strm.total_out) {
 197                         ret = -E2BIG;
 198                         goto out;
 199                 }
 200                 /* we need another page for writing out.  Test this
 201                  * before the total_in so we will pull in a new page for
 202                  * the stream end if required
 203                  */
 204                 if (workspace->strm.avail_out == 0) {
 205                         if (nr_folios == nr_dest_folios) {
 206                                 ret = -E2BIG;
 207                                 goto out;
 208                         }
 209                         out_folio = btrfs_alloc_compr_folio();
 210                         if (out_folio == NULL) {
 211                                 ret = -ENOMEM;
 212                                 goto out;
 213                         }
 214                         cfolio_out = folio_address(out_folio);
 215                         folios[nr_folios] = out_folio;
 216                         nr_folios++;
 217                         workspace->strm.avail_out = PAGE_SIZE;
 218                         workspace->strm.next_out = cfolio_out;
 219                 }
 220                 /* we're all done */
 221                 if (workspace->strm.total_in >= len)
 222                         break;
 223                 if (workspace->strm.total_out > max_out)
 224                         break;
 225         }
 226         workspace->strm.avail_in = 0;
 227         /*
 228          * Call deflate with Z_FINISH flush parameter providing more output
 229          * space but no more input data, until it returns with Z_STREAM_END.
 230          */
 231         while (ret != Z_STREAM_END) {
 232                 ret = zlib_deflate(&workspace->strm, Z_FINISH);
 233                 if (ret == Z_STREAM_END)
 234                         break;
 235                 if (ret != Z_OK && ret != Z_BUF_ERROR) {
 236                         zlib_deflateEnd(&workspace->strm);
 237                         ret = -EIO;
 238                         goto out;
 239                 } else if (workspace->strm.avail_out == 0) {
 240                         /* Get another folio for the stream end. */
 241                         if (nr_folios == nr_dest_folios) {
 242                                 ret = -E2BIG;
 243                                 goto out;
 244                         }
 245                         out_folio = btrfs_alloc_compr_folio();
 246                         if (out_folio == NULL) {
 247                                 ret = -ENOMEM;
 248                                 goto out;
 249                         }
 250                         cfolio_out = folio_address(out_folio);
 251                         folios[nr_folios] = out_folio;
 252                         nr_folios++;
 253                         workspace->strm.avail_out = PAGE_SIZE;
 254                         workspace->strm.next_out = cfolio_out;
 255                 }
 256         }
 257         zlib_deflateEnd(&workspace->strm);
 258
 259         if (workspace->strm.total_out >= workspace->strm.total_in) {
 260                 ret = -E2BIG;
 261                 goto out;
 262         }
 263
 264         ret = 0;
 265         *total_out = workspace->strm.total_out;
 266         *total_in = workspace->strm.total_in;
 267 out:
 268         *out_folios = nr_folios;
 269         if (data_in) {
 270                 kunmap_local(data_in);
 271                 folio_put(in_folio);
 272         }
 273
 274         return ret;
 275 }
 276
 277 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 278 {
 279         struct workspace *workspace = list_entry(ws, struct workspace, list);
 280         int ret = 0, ret2;
 281         int wbits = MAX_WBITS;
 282         char *data_in;
 283         size_t total_out = 0;
 284         unsigned long folio_in_index = 0;
 285         size_t srclen = cb->compressed_len;
 286         unsigned long total_folios_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 287         unsigned long buf_start;
 288         struct folio **folios_in = cb->compressed_folios;
 289
 290         data_in = kmap_local_folio(folios_in[folio_in_index], 0);
 291         workspace->strm.next_in = data_in;
 292         workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 293         workspace->strm.total_in = 0;
 294
 295         workspace->strm.total_out = 0;
 296         workspace->strm.next_out = workspace->buf;
 297         workspace->strm.avail_out = workspace->buf_size;
 298
 299         /* If it's deflate, and it's got no preset dictionary, then
 300            we can tell zlib to skip the adler32 check. */
 301         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 302             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 303             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 304
 305                 wbits = -((data_in[0] >> 4) + 8);
 306                 workspace->strm.next_in += 2;
 307                 workspace->strm.avail_in -= 2;
 308         }
 309
 310         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 311                 pr_warn("BTRFS: inflateInit failed\n");
 312                 kunmap_local(data_in);
 313                 return -EIO;
 314         }
 315         while (workspace->strm.total_in < srclen) {
 316                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 317                 if (ret != Z_OK && ret != Z_STREAM_END)
 318                         break;
 319
 320                 buf_start = total_out;
 321                 total_out = workspace->strm.total_out;
 322
 323                 /* we didn't make progress in this inflate call, we're done */
 324                 if (buf_start == total_out)
 325                         break;
 326
 327                 ret2 = btrfs_decompress_buf2page(workspace->buf,
 328                                 total_out - buf_start, cb, buf_start);
 329                 if (ret2 == 0) {
 330                         ret = 0;
 331                         goto done;
 332                 }
 333
 334                 workspace->strm.next_out = workspace->buf;
 335                 workspace->strm.avail_out = workspace->buf_size;
 336
 337                 if (workspace->strm.avail_in == 0) {
 338                         unsigned long tmp;
 339                         kunmap_local(data_in);
 340                         folio_in_index++;
 341                         if (folio_in_index >= total_folios_in) {
 342                                 data_in = NULL;
 343                                 break;
 344                         }
 345                         data_in = kmap_local_folio(folios_in[folio_in_index], 0);
 346                         workspace->strm.next_in = data_in;
 347                         tmp = srclen - workspace->strm.total_in;
 348                         workspace->strm.avail_in = min(tmp, PAGE_SIZE);
 349                 }
 350         }
 351         if (ret != Z_STREAM_END)
 352                 ret = -EIO;
 353         else
 354                 ret = 0;
 355 done:
 356         zlib_inflateEnd(&workspace->strm);
 357         if (data_in)
 358                 kunmap_local(data_in);
 359         return ret;
 360 }
 361
 362 int zlib_decompress(struct list_head *ws, const u8 *data_in,
 363                 struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
 364                 size_t destlen)
 365 {
 366         struct workspace *workspace = list_entry(ws, struct workspace, list);
 367         int ret = 0;
 368         int wbits = MAX_WBITS;
 369         unsigned long to_copy;
 370
 371         workspace->strm.next_in = data_in;
 372         workspace->strm.avail_in = srclen;
 373         workspace->strm.total_in = 0;
 374
 375         workspace->strm.next_out = workspace->buf;
 376         workspace->strm.avail_out = workspace->buf_size;
 377         workspace->strm.total_out = 0;
 378         /* If it's deflate, and it's got no preset dictionary, then
 379            we can tell zlib to skip the adler32 check. */
 380         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 381             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 382             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 383
 384                 wbits = -((data_in[0] >> 4) + 8);
 385                 workspace->strm.next_in += 2;
 386                 workspace->strm.avail_in -= 2;
 387         }
 388
 389         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 390                 pr_warn("BTRFS: inflateInit failed\n");
 391                 return -EIO;
 392         }
 393
 394         /*
 395          * Everything (in/out buf) should be at most one sector, there should
 396          * be no need to switch any input/output buffer.
 397          */
 398         ret = zlib_inflate(&workspace->strm, Z_FINISH);
 399         to_copy = min(workspace->strm.total_out, destlen);
 400         if (ret != Z_STREAM_END)
 401                 goto out;
 402
 403         memcpy_to_page(dest_page, dest_pgoff, workspace->buf, to_copy);
 404
 405 out:
 406         if (unlikely(to_copy != destlen)) {
 407                 pr_warn_ratelimited("BTRFS: inflate failed, decompressed=%lu expected=%zu\n",
 408                                         to_copy, destlen);
 409                 ret = -EIO;
 410         } else {
 411                 ret = 0;
 412         }
 413
 414         zlib_inflateEnd(&workspace->strm);
 415
 416         if (unlikely(to_copy < destlen))
 417                 memzero_page(dest_page, dest_pgoff + to_copy, destlen - to_copy);
 418         return ret;
 419 }
 420
 421 const struct btrfs_compress_op btrfs_zlib_compress = {
 422         .workspace_manager      = &wsm,
 423         .max_level              = 9,
 424         .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,
 425 };