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 = 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 = 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 (in_page)
 152                                                 put_page(in_page);
 153                                         in_page = find_get_page(mapping,
 154                                                                 start >> PAGE_SHIFT);
 155                                         data_in = page_address(in_page);
 156                                         memcpy(workspace->buf + i * PAGE_SIZE,
 157                                                data_in, PAGE_SIZE);
 158                                         start += PAGE_SIZE;
 159                                 }
 160                                 workspace->strm.next_in = workspace->buf;
 161                         } else {
 162                                 if (in_page)
 163                                         put_page(in_page);
 164                                 in_page = find_get_page(mapping,
 165                                                         start >> PAGE_SHIFT);
 166                                 data_in = page_address(in_page);
 167                                 start += PAGE_SIZE;
 168                                 workspace->strm.next_in = data_in;
 169                         }
 170                         workspace->strm.avail_in = min(bytes_left,
 171                                                        (unsigned long) workspace->buf_size);
 172                 }
 173
 174                 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
 175                 if (ret != Z_OK) {
 176                         pr_debug("BTRFS: deflate in loop returned %d\n",
 177                                ret);
 178                         zlib_deflateEnd(&workspace->strm);
 179                         ret = -EIO;
 180                         goto out;
 181                 }
 182
 183                 /* we're making it bigger, give up */
 184                 if (workspace->strm.total_in > 8192 &&
 185                     workspace->strm.total_in <
 186                     workspace->strm.total_out) {
 187                         ret = -E2BIG;
 188                         goto out;
 189                 }
 190                 /* we need another page for writing out.  Test this
 191                  * before the total_in so we will pull in a new page for
 192                  * the stream end if required
 193                  */
 194                 if (workspace->strm.avail_out == 0) {
 195                         if (nr_pages == nr_dest_pages) {
 196                                 out_page = NULL;
 197                                 ret = -E2BIG;
 198                                 goto out;
 199                         }
 200                         out_page = alloc_page(GFP_NOFS);
 201                         if (out_page == NULL) {
 202                                 ret = -ENOMEM;
 203                                 goto out;
 204                         }
 205                         cpage_out = page_address(out_page);
 206                         pages[nr_pages] = out_page;
 207                         nr_pages++;
 208                         workspace->strm.avail_out = PAGE_SIZE;
 209                         workspace->strm.next_out = cpage_out;
 210                 }
 211                 /* we're all done */
 212                 if (workspace->strm.total_in >= len)
 213                         break;
 214                 if (workspace->strm.total_out > max_out)
 215                         break;
 216         }
 217         workspace->strm.avail_in = 0;
 218         /*
 219          * Call deflate with Z_FINISH flush parameter providing more output
 220          * space but no more input data, until it returns with Z_STREAM_END.
 221          */
 222         while (ret != Z_STREAM_END) {
 223                 ret = zlib_deflate(&workspace->strm, Z_FINISH);
 224                 if (ret == Z_STREAM_END)
 225                         break;
 226                 if (ret != Z_OK && ret != Z_BUF_ERROR) {
 227                         zlib_deflateEnd(&workspace->strm);
 228                         ret = -EIO;
 229                         goto out;
 230                 } else if (workspace->strm.avail_out == 0) {
 231                         /* get another page for the stream end */
 232                         if (nr_pages == nr_dest_pages) {
 233                                 out_page = NULL;
 234                                 ret = -E2BIG;
 235                                 goto out;
 236                         }
 237                         out_page = alloc_page(GFP_NOFS);
 238                         if (out_page == NULL) {
 239                                 ret = -ENOMEM;
 240                                 goto out;
 241                         }
 242                         cpage_out = page_address(out_page);
 243                         pages[nr_pages] = out_page;
 244                         nr_pages++;
 245                         workspace->strm.avail_out = PAGE_SIZE;
 246                         workspace->strm.next_out = cpage_out;
 247                 }
 248         }
 249         zlib_deflateEnd(&workspace->strm);
 250
 251         if (workspace->strm.total_out >= workspace->strm.total_in) {
 252                 ret = -E2BIG;
 253                 goto out;
 254         }
 255
 256         ret = 0;
 257         *total_out = workspace->strm.total_out;
 258         *total_in = workspace->strm.total_in;
 259 out:
 260         *out_pages = nr_pages;
 261         if (in_page)
 262                 put_page(in_page);
 263         return ret;
 264 }
 265
 266 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 267 {
 268         struct workspace *workspace = list_entry(ws, struct workspace, list);
 269         int ret = 0, ret2;
 270         int wbits = MAX_WBITS;
 271         char *data_in;
 272         size_t total_out = 0;
 273         unsigned long page_in_index = 0;
 274         size_t srclen = cb->compressed_len;
 275         unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 276         unsigned long buf_start;
 277         struct page **pages_in = cb->compressed_pages;
 278
 279         data_in = page_address(pages_in[page_in_index]);
 280         workspace->strm.next_in = data_in;
 281         workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 282         workspace->strm.total_in = 0;
 283
 284         workspace->strm.total_out = 0;
 285         workspace->strm.next_out = workspace->buf;
 286         workspace->strm.avail_out = workspace->buf_size;
 287
 288         /* If it's deflate, and it's got no preset dictionary, then
 289            we can tell zlib to skip the adler32 check. */
 290         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 291             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 292             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 293
 294                 wbits = -((data_in[0] >> 4) + 8);
 295                 workspace->strm.next_in += 2;
 296                 workspace->strm.avail_in -= 2;
 297         }
 298
 299         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 300                 pr_warn("BTRFS: inflateInit failed\n");
 301                 return -EIO;
 302         }
 303         while (workspace->strm.total_in < srclen) {
 304                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 305                 if (ret != Z_OK && ret != Z_STREAM_END)
 306                         break;
 307
 308                 buf_start = total_out;
 309                 total_out = workspace->strm.total_out;
 310
 311                 /* we didn't make progress in this inflate call, we're done */
 312                 if (buf_start == total_out)
 313                         break;
 314
 315                 ret2 = btrfs_decompress_buf2page(workspace->buf,
 316                                 total_out - buf_start, cb, buf_start);
 317                 if (ret2 == 0) {
 318                         ret = 0;
 319                         goto done;
 320                 }
 321
 322                 workspace->strm.next_out = workspace->buf;
 323                 workspace->strm.avail_out = workspace->buf_size;
 324
 325                 if (workspace->strm.avail_in == 0) {
 326                         unsigned long tmp;
 327
 328                         page_in_index++;
 329                         if (page_in_index >= total_pages_in) {
 330                                 data_in = NULL;
 331                                 break;
 332                         }
 333                         data_in = page_address(pages_in[page_in_index]);
 334                         workspace->strm.next_in = data_in;
 335                         tmp = srclen - workspace->strm.total_in;
 336                         workspace->strm.avail_in = min(tmp, PAGE_SIZE);
 337                 }
 338         }
 339         if (ret != Z_STREAM_END)
 340                 ret = -EIO;
 341         else
 342                 ret = 0;
 343 done:
 344         zlib_inflateEnd(&workspace->strm);
 345         if (!ret)
 346                 zero_fill_bio(cb->orig_bio);
 347         return ret;
 348 }
 349
 350 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 351                 struct page *dest_page, unsigned long start_byte, size_t srclen,
 352                 size_t destlen)
 353 {
 354         struct workspace *workspace = list_entry(ws, struct workspace, list);
 355         int ret = 0;
 356         int wbits = MAX_WBITS;
 357         unsigned long bytes_left;
 358         unsigned long total_out = 0;
 359         unsigned long pg_offset = 0;
 360
 361         destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 362         bytes_left = destlen;
 363
 364         workspace->strm.next_in = data_in;
 365         workspace->strm.avail_in = srclen;
 366         workspace->strm.total_in = 0;
 367
 368         workspace->strm.next_out = workspace->buf;
 369         workspace->strm.avail_out = workspace->buf_size;
 370         workspace->strm.total_out = 0;
 371         /* If it's deflate, and it's got no preset dictionary, then
 372            we can tell zlib to skip the adler32 check. */
 373         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 374             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 375             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 376
 377                 wbits = -((data_in[0] >> 4) + 8);
 378                 workspace->strm.next_in += 2;
 379                 workspace->strm.avail_in -= 2;
 380         }
 381
 382         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 383                 pr_warn("BTRFS: inflateInit failed\n");
 384                 return -EIO;
 385         }
 386
 387         while (bytes_left > 0) {
 388                 unsigned long buf_start;
 389                 unsigned long buf_offset;
 390                 unsigned long bytes;
 391
 392                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 393                 if (ret != Z_OK && ret != Z_STREAM_END)
 394                         break;
 395
 396                 buf_start = total_out;
 397                 total_out = workspace->strm.total_out;
 398
 399                 if (total_out == buf_start) {
 400                         ret = -EIO;
 401                         break;
 402                 }
 403
 404                 if (total_out <= start_byte)
 405                         goto next;
 406
 407                 if (total_out > start_byte && buf_start < start_byte)
 408                         buf_offset = start_byte - buf_start;
 409                 else
 410                         buf_offset = 0;
 411
 412                 bytes = min(PAGE_SIZE - pg_offset,
 413                             PAGE_SIZE - (buf_offset % PAGE_SIZE));
 414                 bytes = min(bytes, bytes_left);
 415
 416                 memcpy_to_page(dest_page, pg_offset,
 417                                workspace->buf + buf_offset, bytes);
 418
 419                 pg_offset += bytes;
 420                 bytes_left -= bytes;
 421 next:
 422                 workspace->strm.next_out = workspace->buf;
 423                 workspace->strm.avail_out = workspace->buf_size;
 424         }
 425
 426         if (ret != Z_STREAM_END && bytes_left != 0)
 427                 ret = -EIO;
 428         else
 429                 ret = 0;
 430
 431         zlib_inflateEnd(&workspace->strm);
 432
 433         /*
 434          * this should only happen if zlib returned fewer bytes than we
 435          * expected.  btrfs_get_block is responsible for zeroing from the
 436          * end of the inline extent (destlen) to the end of the page
 437          */
 438         if (pg_offset < destlen) {
 439                 memzero_page(dest_page, pg_offset, destlen - pg_offset);
 440         }
 441         return ret;
 442 }
 443
 444 const struct btrfs_compress_op btrfs_zlib_compress = {
 445         .workspace_manager      = &wsm,
 446         .max_level              = 9,
 447         .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,
 448 };