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 = 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_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 = NULL;
 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 = page_address(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 (data_in) {
 152                                                 kunmap_local(data_in);
 153                                                 put_page(in_page);
 154                                         }
 155                                         in_page = find_get_page(mapping,
 156                                                                 start >> PAGE_SHIFT);
 157                                         data_in = kmap_local_page(in_page);
 158                                         copy_page(workspace->buf + i * PAGE_SIZE,
 159                                                   data_in);
 160                                         start += PAGE_SIZE;
 161                                 }
 162                                 workspace->strm.next_in = workspace->buf;
 163                         } else {
 164                                 if (data_in) {
 165                                         kunmap_local(data_in);
 166                                         put_page(in_page);
 167                                 }
 168                                 in_page = find_get_page(mapping,
 169                                                         start >> PAGE_SHIFT);
 170                                 data_in = kmap_local_page(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                         if (nr_pages == nr_dest_pages) {
 200                                 ret = -E2BIG;
 201                                 goto out;
 202                         }
 203                         out_page = alloc_page(GFP_NOFS);
 204                         if (out_page == NULL) {
 205                                 ret = -ENOMEM;
 206                                 goto out;
 207                         }
 208                         cpage_out = page_address(out_page);
 209                         pages[nr_pages] = out_page;
 210                         nr_pages++;
 211                         workspace->strm.avail_out = PAGE_SIZE;
 212                         workspace->strm.next_out = cpage_out;
 213                 }
 214                 /* we're all done */
 215                 if (workspace->strm.total_in >= len)
 216                         break;
 217                 if (workspace->strm.total_out > max_out)
 218                         break;
 219         }
 220         workspace->strm.avail_in = 0;
 221         /*
 222          * Call deflate with Z_FINISH flush parameter providing more output
 223          * space but no more input data, until it returns with Z_STREAM_END.
 224          */
 225         while (ret != Z_STREAM_END) {
 226                 ret = zlib_deflate(&workspace->strm, Z_FINISH);
 227                 if (ret == Z_STREAM_END)
 228                         break;
 229                 if (ret != Z_OK && ret != Z_BUF_ERROR) {
 230                         zlib_deflateEnd(&workspace->strm);
 231                         ret = -EIO;
 232                         goto out;
 233                 } else if (workspace->strm.avail_out == 0) {
 234                         /* get another page for the stream end */
 235                         if (nr_pages == nr_dest_pages) {
 236                                 ret = -E2BIG;
 237                                 goto out;
 238                         }
 239                         out_page = alloc_page(GFP_NOFS);
 240                         if (out_page == NULL) {
 241                                 ret = -ENOMEM;
 242                                 goto out;
 243                         }
 244                         cpage_out = page_address(out_page);
 245                         pages[nr_pages] = out_page;
 246                         nr_pages++;
 247                         workspace->strm.avail_out = PAGE_SIZE;
 248                         workspace->strm.next_out = cpage_out;
 249                 }
 250         }
 251         zlib_deflateEnd(&workspace->strm);
 252
 253         if (workspace->strm.total_out >= workspace->strm.total_in) {
 254                 ret = -E2BIG;
 255                 goto out;
 256         }
 257
 258         ret = 0;
 259         *total_out = workspace->strm.total_out;
 260         *total_in = workspace->strm.total_in;
 261 out:
 262         *out_pages = nr_pages;
 263         if (data_in) {
 264                 kunmap_local(data_in);
 265                 put_page(in_page);
 266         }
 267
 268         return ret;
 269 }
 270
 271 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 272 {
 273         struct workspace *workspace = list_entry(ws, struct workspace, list);
 274         int ret = 0, ret2;
 275         int wbits = MAX_WBITS;
 276         char *data_in;
 277         size_t total_out = 0;
 278         unsigned long page_in_index = 0;
 279         size_t srclen = cb->compressed_len;
 280         unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 281         unsigned long buf_start;
 282         struct page **pages_in = cb->compressed_pages;
 283
 284         data_in = kmap_local_page(pages_in[page_in_index]);
 285         workspace->strm.next_in = data_in;
 286         workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 287         workspace->strm.total_in = 0;
 288
 289         workspace->strm.total_out = 0;
 290         workspace->strm.next_out = workspace->buf;
 291         workspace->strm.avail_out = workspace->buf_size;
 292
 293         /* If it's deflate, and it's got no preset dictionary, then
 294            we can tell zlib to skip the adler32 check. */
 295         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 296             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 297             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 298
 299                 wbits = -((data_in[0] >> 4) + 8);
 300                 workspace->strm.next_in += 2;
 301                 workspace->strm.avail_in -= 2;
 302         }
 303
 304         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 305                 pr_warn("BTRFS: inflateInit failed\n");
 306                 kunmap_local(data_in);
 307                 return -EIO;
 308         }
 309         while (workspace->strm.total_in < srclen) {
 310                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 311                 if (ret != Z_OK && ret != Z_STREAM_END)
 312                         break;
 313
 314                 buf_start = total_out;
 315                 total_out = workspace->strm.total_out;
 316
 317                 /* we didn't make progress in this inflate call, we're done */
 318                 if (buf_start == total_out)
 319                         break;
 320
 321                 ret2 = btrfs_decompress_buf2page(workspace->buf,
 322                                 total_out - buf_start, cb, buf_start);
 323                 if (ret2 == 0) {
 324                         ret = 0;
 325                         goto done;
 326                 }
 327
 328                 workspace->strm.next_out = workspace->buf;
 329                 workspace->strm.avail_out = workspace->buf_size;
 330
 331                 if (workspace->strm.avail_in == 0) {
 332                         unsigned long tmp;
 333                         kunmap_local(data_in);
 334                         page_in_index++;
 335                         if (page_in_index >= total_pages_in) {
 336                                 data_in = NULL;
 337                                 break;
 338                         }
 339                         data_in = kmap_local_page(pages_in[page_in_index]);
 340                         workspace->strm.next_in = data_in;
 341                         tmp = srclen - workspace->strm.total_in;
 342                         workspace->strm.avail_in = min(tmp, PAGE_SIZE);
 343                 }
 344         }
 345         if (ret != Z_STREAM_END)
 346                 ret = -EIO;
 347         else
 348                 ret = 0;
 349 done:
 350         zlib_inflateEnd(&workspace->strm);
 351         if (data_in)
 352                 kunmap_local(data_in);
 353         return ret;
 354 }
 355
 356 int zlib_decompress(struct list_head *ws, const u8 *data_in,
 357                 struct page *dest_page, unsigned long start_byte, size_t srclen,
 358                 size_t destlen)
 359 {
 360         struct workspace *workspace = list_entry(ws, struct workspace, list);
 361         int ret = 0;
 362         int wbits = MAX_WBITS;
 363         unsigned long bytes_left;
 364         unsigned long total_out = 0;
 365         unsigned long pg_offset = 0;
 366
 367         destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 368         bytes_left = destlen;
 369
 370         workspace->strm.next_in = data_in;
 371         workspace->strm.avail_in = srclen;
 372         workspace->strm.total_in = 0;
 373
 374         workspace->strm.next_out = workspace->buf;
 375         workspace->strm.avail_out = workspace->buf_size;
 376         workspace->strm.total_out = 0;
 377         /* If it's deflate, and it's got no preset dictionary, then
 378            we can tell zlib to skip the adler32 check. */
 379         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 380             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 381             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 382
 383                 wbits = -((data_in[0] >> 4) + 8);
 384                 workspace->strm.next_in += 2;
 385                 workspace->strm.avail_in -= 2;
 386         }
 387
 388         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 389                 pr_warn("BTRFS: inflateInit failed\n");
 390                 return -EIO;
 391         }
 392
 393         while (bytes_left > 0) {
 394                 unsigned long buf_start;
 395                 unsigned long buf_offset;
 396                 unsigned long bytes;
 397
 398                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 399                 if (ret != Z_OK && ret != Z_STREAM_END)
 400                         break;
 401
 402                 buf_start = total_out;
 403                 total_out = workspace->strm.total_out;
 404
 405                 if (total_out == buf_start) {
 406                         ret = -EIO;
 407                         break;
 408                 }
 409
 410                 if (total_out <= start_byte)
 411                         goto next;
 412
 413                 if (total_out > start_byte && buf_start < start_byte)
 414                         buf_offset = start_byte - buf_start;
 415                 else
 416                         buf_offset = 0;
 417
 418                 bytes = min(PAGE_SIZE - pg_offset,
 419                             PAGE_SIZE - (buf_offset % PAGE_SIZE));
 420                 bytes = min(bytes, bytes_left);
 421
 422                 memcpy_to_page(dest_page, pg_offset,
 423                                workspace->buf + buf_offset, bytes);
 424
 425                 pg_offset += bytes;
 426                 bytes_left -= bytes;
 427 next:
 428                 workspace->strm.next_out = workspace->buf;
 429                 workspace->strm.avail_out = workspace->buf_size;
 430         }
 431
 432         if (ret != Z_STREAM_END && bytes_left != 0)
 433                 ret = -EIO;
 434         else
 435                 ret = 0;
 436
 437         zlib_inflateEnd(&workspace->strm);
 438
 439         /*
 440          * this should only happen if zlib returned fewer bytes than we
 441          * expected.  btrfs_get_block is responsible for zeroing from the
 442          * end of the inline extent (destlen) to the end of the page
 443          */
 444         if (pg_offset < destlen) {
 445                 memzero_page(dest_page, pg_offset, destlen - pg_offset);
 446         }
 447         return ret;
 448 }
 449
 450 const struct btrfs_compress_op btrfs_zlib_compress = {
 451         .workspace_manager      = &wsm,
 452         .max_level              = 9,
 453         .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,
 454 };