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 <dwmw2@infradead.org>
   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 = kvmalloc(workspacesize, GFP_KERNEL);
  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_pages(struct list_head *ws, struct address_space *mapping,
  95                 u64 start, struct page **pages, unsigned long *out_pages,
  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;
 101         char *cpage_out;
 102         int nr_pages = 0;
 103         struct page *in_page = NULL;
 104         struct page *out_page = NULL;
 105         unsigned long bytes_left;
 106         unsigned int in_buf_pages;
 107         unsigned long len = *total_out;
 108         unsigned long nr_dest_pages = *out_pages;
 109         const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
 110
 111         *out_pages = 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_page = alloc_page(GFP_NOFS);
 125         if (out_page == NULL) {
 126                 ret = -ENOMEM;
 127                 goto out;
 128         }
 129         cpage_out = kmap(out_page);
 130         pages[0] = out_page;
 131         nr_pages = 1;
 132
 133         workspace->strm.next_in = workspace->buf;
 134         workspace->strm.avail_in = 0;
 135         workspace->strm.next_out = cpage_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_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
 146                                            workspace->buf_size / PAGE_SIZE);
 147                         if (in_buf_pages > 1) {
 148                                 int i;
 149
 150                                 for (i = 0; i < in_buf_pages; i++) {
 151                                         if (in_page) {
 152                                                 kunmap(in_page);
 153                                                 put_page(in_page);
 154                                         }
 155                                         in_page = find_get_page(mapping,
 156                                                                 start >> PAGE_SHIFT);
 157                                         data_in = kmap(in_page);
 158                                         memcpy(workspace->buf + i * PAGE_SIZE,
 159                                                data_in, PAGE_SIZE);
 160                                         start += PAGE_SIZE;
 161                                 }
 162                                 workspace->strm.next_in = workspace->buf;
 163                         } else {
 164                                 if (in_page) {
 165                                         kunmap(in_page);
 166                                         put_page(in_page);
 167                                 }
 168                                 in_page = find_get_page(mapping,
 169                                                         start >> PAGE_SHIFT);
 170                                 data_in = kmap(in_page);
 171                                 start += PAGE_SIZE;
 172                                 workspace->strm.next_in = data_in;
 173                         }
 174                         workspace->strm.avail_in = min(bytes_left,
 175                                                        (unsigned long) workspace->buf_size);
 176                 }
 177
 178                 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
 179                 if (ret != Z_OK) {
 180                         pr_debug("BTRFS: deflate in loop returned %d\n",
 181                                ret);
 182                         zlib_deflateEnd(&workspace->strm);
 183                         ret = -EIO;
 184                         goto out;
 185                 }
 186
 187                 /* we're making it bigger, give up */
 188                 if (workspace->strm.total_in > 8192 &&
 189                     workspace->strm.total_in <
 190                     workspace->strm.total_out) {
 191                         ret = -E2BIG;
 192                         goto out;
 193                 }
 194                 /* we need another page for writing out.  Test this
 195                  * before the total_in so we will pull in a new page for
 196                  * the stream end if required
 197                  */
 198                 if (workspace->strm.avail_out == 0) {
 199                         kunmap(out_page);
 200                         if (nr_pages == nr_dest_pages) {
 201                                 out_page = NULL;
 202                                 ret = -E2BIG;
 203                                 goto out;
 204                         }
 205                         out_page = alloc_page(GFP_NOFS);
 206                         if (out_page == NULL) {
 207                                 ret = -ENOMEM;
 208                                 goto out;
 209                         }
 210                         cpage_out = kmap(out_page);
 211                         pages[nr_pages] = out_page;
 212                         nr_pages++;
 213                         workspace->strm.avail_out = PAGE_SIZE;
 214                         workspace->strm.next_out = cpage_out;
 215                 }
 216                 /* we're all done */
 217                 if (workspace->strm.total_in >= len)
 218                         break;
 219                 if (workspace->strm.total_out > max_out)
 220                         break;
 221         }
 222         workspace->strm.avail_in = 0;
 223         /*
 224          * Call deflate with Z_FINISH flush parameter providing more output
 225          * space but no more input data, until it returns with Z_STREAM_END.
 226          */
 227         while (ret != Z_STREAM_END) {
 228                 ret = zlib_deflate(&workspace->strm, Z_FINISH);
 229                 if (ret == Z_STREAM_END)
 230                         break;
 231                 if (ret != Z_OK && ret != Z_BUF_ERROR) {
 232                         zlib_deflateEnd(&workspace->strm);
 233                         ret = -EIO;
 234                         goto out;
 235                 } else if (workspace->strm.avail_out == 0) {
 236                         /* get another page for the stream end */
 237                         kunmap(out_page);
 238                         if (nr_pages == nr_dest_pages) {
 239                                 out_page = NULL;
 240                                 ret = -E2BIG;
 241                                 goto out;
 242                         }
 243                         out_page = alloc_page(GFP_NOFS);
 244                         if (out_page == NULL) {
 245                                 ret = -ENOMEM;
 246                                 goto out;
 247                         }
 248                         cpage_out = kmap(out_page);
 249                         pages[nr_pages] = out_page;
 250                         nr_pages++;
 251                         workspace->strm.avail_out = PAGE_SIZE;
 252                         workspace->strm.next_out = cpage_out;
 253                 }
 254         }
 255         zlib_deflateEnd(&workspace->strm);
 256
 257         if (workspace->strm.total_out >= workspace->strm.total_in) {
 258                 ret = -E2BIG;
 259                 goto out;
 260         }
 261
 262         ret = 0;
 263         *total_out = workspace->strm.total_out;
 264         *total_in = workspace->strm.total_in;
 265 out:
 266         *out_pages = nr_pages;
 267         if (out_page)
 268                 kunmap(out_page);
 269
 270         if (in_page) {
 271                 kunmap(in_page);
 272                 put_page(in_page);
 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 page_in_index = 0;
 285         size_t srclen = cb->compressed_len;
 286         unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 287         unsigned long buf_start;
 288         struct page **pages_in = cb->compressed_pages;
 289
 290         data_in = kmap(pages_in[page_in_index]);
 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(pages_in[page_in_index]);
 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(pages_in[page_in_index]);
 340                         page_in_index++;
 341                         if (page_in_index >= total_pages_in) {
 342                                 data_in = NULL;
 343                                 break;
 344                         }
 345                         data_in = kmap(pages_in[page_in_index]);
 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(pages_in[page_in_index]);
 359         if (!ret)
 360                 zero_fill_bio(cb->orig_bio);
 361         return ret;
 362 }
 363
 364 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 365                 struct page *dest_page, unsigned long start_byte, size_t srclen,
 366                 size_t destlen)
 367 {
 368         struct workspace *workspace = list_entry(ws, struct workspace, list);
 369         int ret = 0;
 370         int wbits = MAX_WBITS;
 371         unsigned long bytes_left;
 372         unsigned long total_out = 0;
 373         unsigned long pg_offset = 0;
 374
 375         destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 376         bytes_left = destlen;
 377
 378         workspace->strm.next_in = data_in;
 379         workspace->strm.avail_in = srclen;
 380         workspace->strm.total_in = 0;
 381
 382         workspace->strm.next_out = workspace->buf;
 383         workspace->strm.avail_out = workspace->buf_size;
 384         workspace->strm.total_out = 0;
 385         /* If it's deflate, and it's got no preset dictionary, then
 386            we can tell zlib to skip the adler32 check. */
 387         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 388             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 389             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 390
 391                 wbits = -((data_in[0] >> 4) + 8);
 392                 workspace->strm.next_in += 2;
 393                 workspace->strm.avail_in -= 2;
 394         }
 395
 396         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 397                 pr_warn("BTRFS: inflateInit failed\n");
 398                 return -EIO;
 399         }
 400
 401         while (bytes_left > 0) {
 402                 unsigned long buf_start;
 403                 unsigned long buf_offset;
 404                 unsigned long bytes;
 405
 406                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 407                 if (ret != Z_OK && ret != Z_STREAM_END)
 408                         break;
 409
 410                 buf_start = total_out;
 411                 total_out = workspace->strm.total_out;
 412
 413                 if (total_out == buf_start) {
 414                         ret = -EIO;
 415                         break;
 416                 }
 417
 418                 if (total_out <= start_byte)
 419                         goto next;
 420
 421                 if (total_out > start_byte && buf_start < start_byte)
 422                         buf_offset = start_byte - buf_start;
 423                 else
 424                         buf_offset = 0;
 425
 426                 bytes = min(PAGE_SIZE - pg_offset,
 427                             PAGE_SIZE - (buf_offset % PAGE_SIZE));
 428                 bytes = min(bytes, bytes_left);
 429
 430                 memcpy_to_page(dest_page, pg_offset,
 431                                workspace->buf + buf_offset, bytes);
 432
 433                 pg_offset += bytes;
 434                 bytes_left -= bytes;
 435 next:
 436                 workspace->strm.next_out = workspace->buf;
 437                 workspace->strm.avail_out = workspace->buf_size;
 438         }
 439
 440         if (ret != Z_STREAM_END && bytes_left != 0)
 441                 ret = -EIO;
 442         else
 443                 ret = 0;
 444
 445         zlib_inflateEnd(&workspace->strm);
 446
 447         /*
 448          * this should only happen if zlib returned fewer bytes than we
 449          * expected.  btrfs_get_block is responsible for zeroing from the
 450          * end of the inline extent (destlen) to the end of the page
 451          */
 452         if (pg_offset < destlen) {
 453                 memzero_page(dest_page, pg_offset, destlen - pg_offset);
 454         }
 455         return ret;
 456 }
 457
 458 const struct btrfs_compress_op btrfs_zlib_compress = {
 459         .workspace_manager      = &wsm,
 460         .max_level              = 9,
 461         .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,
 462 };