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 struct workspace {
  24         z_stream strm;
  25         char *buf;
  26         struct list_head list;
  27         int level;
  28 };
  29
  30 static struct workspace_manager wsm;
  31
  32 struct list_head *zlib_get_workspace(unsigned int level)
  33 {
  34         struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
  35         struct workspace *workspace = list_entry(ws, struct workspace, list);
  36
  37         workspace->level = level;
  38
  39         return ws;
  40 }
  41
  42 void zlib_free_workspace(struct list_head *ws)
  43 {
  44         struct workspace *workspace = list_entry(ws, struct workspace, list);
  45
  46         kvfree(workspace->strm.workspace);
  47         kfree(workspace->buf);
  48         kfree(workspace);
  49 }
  50
  51 struct list_head *zlib_alloc_workspace(unsigned int level)
  52 {
  53         struct workspace *workspace;
  54         int workspacesize;
  55
  56         workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
  57         if (!workspace)
  58                 return ERR_PTR(-ENOMEM);
  59
  60         workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
  61                         zlib_inflate_workspacesize());
  62         workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
  63         workspace->level = level;
  64         workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  65         if (!workspace->strm.workspace || !workspace->buf)
  66                 goto fail;
  67
  68         INIT_LIST_HEAD(&workspace->list);
  69
  70         return &workspace->list;
  71 fail:
  72         zlib_free_workspace(&workspace->list);
  73         return ERR_PTR(-ENOMEM);
  74 }
  75
  76 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
  77                 u64 start, struct page **pages, unsigned long *out_pages,
  78                 unsigned long *total_in, unsigned long *total_out)
  79 {
  80         struct workspace *workspace = list_entry(ws, struct workspace, list);
  81         int ret;
  82         char *data_in;
  83         char *cpage_out;
  84         int nr_pages = 0;
  85         struct page *in_page = NULL;
  86         struct page *out_page = NULL;
  87         unsigned long bytes_left;
  88         unsigned long len = *total_out;
  89         unsigned long nr_dest_pages = *out_pages;
  90         const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
  91
  92         *out_pages = 0;
  93         *total_out = 0;
  94         *total_in = 0;
  95
  96         if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
  97                 pr_warn("BTRFS: deflateInit failed\n");
  98                 ret = -EIO;
  99                 goto out;
 100         }
 101
 102         workspace->strm.total_in = 0;
 103         workspace->strm.total_out = 0;
 104
 105         in_page = find_get_page(mapping, start >> PAGE_SHIFT);
 106         data_in = kmap(in_page);
 107
 108         out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 109         if (out_page == NULL) {
 110                 ret = -ENOMEM;
 111                 goto out;
 112         }
 113         cpage_out = kmap(out_page);
 114         pages[0] = out_page;
 115         nr_pages = 1;
 116
 117         workspace->strm.next_in = data_in;
 118         workspace->strm.next_out = cpage_out;
 119         workspace->strm.avail_out = PAGE_SIZE;
 120         workspace->strm.avail_in = min(len, PAGE_SIZE);
 121
 122         while (workspace->strm.total_in < len) {
 123                 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
 124                 if (ret != Z_OK) {
 125                         pr_debug("BTRFS: deflate in loop returned %d\n",
 126                                ret);
 127                         zlib_deflateEnd(&workspace->strm);
 128                         ret = -EIO;
 129                         goto out;
 130                 }
 131
 132                 /* we're making it bigger, give up */
 133                 if (workspace->strm.total_in > 8192 &&
 134                     workspace->strm.total_in <
 135                     workspace->strm.total_out) {
 136                         ret = -E2BIG;
 137                         goto out;
 138                 }
 139                 /* we need another page for writing out.  Test this
 140                  * before the total_in so we will pull in a new page for
 141                  * the stream end if required
 142                  */
 143                 if (workspace->strm.avail_out == 0) {
 144                         kunmap(out_page);
 145                         if (nr_pages == nr_dest_pages) {
 146                                 out_page = NULL;
 147                                 ret = -E2BIG;
 148                                 goto out;
 149                         }
 150                         out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 151                         if (out_page == NULL) {
 152                                 ret = -ENOMEM;
 153                                 goto out;
 154                         }
 155                         cpage_out = kmap(out_page);
 156                         pages[nr_pages] = out_page;
 157                         nr_pages++;
 158                         workspace->strm.avail_out = PAGE_SIZE;
 159                         workspace->strm.next_out = cpage_out;
 160                 }
 161                 /* we're all done */
 162                 if (workspace->strm.total_in >= len)
 163                         break;
 164
 165                 /* we've read in a full page, get a new one */
 166                 if (workspace->strm.avail_in == 0) {
 167                         if (workspace->strm.total_out > max_out)
 168                                 break;
 169
 170                         bytes_left = len - workspace->strm.total_in;
 171                         kunmap(in_page);
 172                         put_page(in_page);
 173
 174                         start += PAGE_SIZE;
 175                         in_page = find_get_page(mapping,
 176                                                 start >> PAGE_SHIFT);
 177                         data_in = kmap(in_page);
 178                         workspace->strm.avail_in = min(bytes_left,
 179                                                            PAGE_SIZE);
 180                         workspace->strm.next_in = data_in;
 181                 }
 182         }
 183         workspace->strm.avail_in = 0;
 184         ret = zlib_deflate(&workspace->strm, Z_FINISH);
 185         zlib_deflateEnd(&workspace->strm);
 186
 187         if (ret != Z_STREAM_END) {
 188                 ret = -EIO;
 189                 goto out;
 190         }
 191
 192         if (workspace->strm.total_out >= workspace->strm.total_in) {
 193                 ret = -E2BIG;
 194                 goto out;
 195         }
 196
 197         ret = 0;
 198         *total_out = workspace->strm.total_out;
 199         *total_in = workspace->strm.total_in;
 200 out:
 201         *out_pages = nr_pages;
 202         if (out_page)
 203                 kunmap(out_page);
 204
 205         if (in_page) {
 206                 kunmap(in_page);
 207                 put_page(in_page);
 208         }
 209         return ret;
 210 }
 211
 212 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 213 {
 214         struct workspace *workspace = list_entry(ws, struct workspace, list);
 215         int ret = 0, ret2;
 216         int wbits = MAX_WBITS;
 217         char *data_in;
 218         size_t total_out = 0;
 219         unsigned long page_in_index = 0;
 220         size_t srclen = cb->compressed_len;
 221         unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 222         unsigned long buf_start;
 223         struct page **pages_in = cb->compressed_pages;
 224         u64 disk_start = cb->start;
 225         struct bio *orig_bio = cb->orig_bio;
 226
 227         data_in = kmap(pages_in[page_in_index]);
 228         workspace->strm.next_in = data_in;
 229         workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 230         workspace->strm.total_in = 0;
 231
 232         workspace->strm.total_out = 0;
 233         workspace->strm.next_out = workspace->buf;
 234         workspace->strm.avail_out = PAGE_SIZE;
 235
 236         /* If it's deflate, and it's got no preset dictionary, then
 237            we can tell zlib to skip the adler32 check. */
 238         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 239             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 240             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 241
 242                 wbits = -((data_in[0] >> 4) + 8);
 243                 workspace->strm.next_in += 2;
 244                 workspace->strm.avail_in -= 2;
 245         }
 246
 247         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 248                 pr_warn("BTRFS: inflateInit failed\n");
 249                 kunmap(pages_in[page_in_index]);
 250                 return -EIO;
 251         }
 252         while (workspace->strm.total_in < srclen) {
 253                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 254                 if (ret != Z_OK && ret != Z_STREAM_END)
 255                         break;
 256
 257                 buf_start = total_out;
 258                 total_out = workspace->strm.total_out;
 259
 260                 /* we didn't make progress in this inflate call, we're done */
 261                 if (buf_start == total_out)
 262                         break;
 263
 264                 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
 265                                                  total_out, disk_start,
 266                                                  orig_bio);
 267                 if (ret2 == 0) {
 268                         ret = 0;
 269                         goto done;
 270                 }
 271
 272                 workspace->strm.next_out = workspace->buf;
 273                 workspace->strm.avail_out = PAGE_SIZE;
 274
 275                 if (workspace->strm.avail_in == 0) {
 276                         unsigned long tmp;
 277                         kunmap(pages_in[page_in_index]);
 278                         page_in_index++;
 279                         if (page_in_index >= total_pages_in) {
 280                                 data_in = NULL;
 281                                 break;
 282                         }
 283                         data_in = kmap(pages_in[page_in_index]);
 284                         workspace->strm.next_in = data_in;
 285                         tmp = srclen - workspace->strm.total_in;
 286                         workspace->strm.avail_in = min(tmp,
 287                                                            PAGE_SIZE);
 288                 }
 289         }
 290         if (ret != Z_STREAM_END)
 291                 ret = -EIO;
 292         else
 293                 ret = 0;
 294 done:
 295         zlib_inflateEnd(&workspace->strm);
 296         if (data_in)
 297                 kunmap(pages_in[page_in_index]);
 298         if (!ret)
 299                 zero_fill_bio(orig_bio);
 300         return ret;
 301 }
 302
 303 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 304                 struct page *dest_page, unsigned long start_byte, size_t srclen,
 305                 size_t destlen)
 306 {
 307         struct workspace *workspace = list_entry(ws, struct workspace, list);
 308         int ret = 0;
 309         int wbits = MAX_WBITS;
 310         unsigned long bytes_left;
 311         unsigned long total_out = 0;
 312         unsigned long pg_offset = 0;
 313         char *kaddr;
 314
 315         destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 316         bytes_left = destlen;
 317
 318         workspace->strm.next_in = data_in;
 319         workspace->strm.avail_in = srclen;
 320         workspace->strm.total_in = 0;
 321
 322         workspace->strm.next_out = workspace->buf;
 323         workspace->strm.avail_out = PAGE_SIZE;
 324         workspace->strm.total_out = 0;
 325         /* If it's deflate, and it's got no preset dictionary, then
 326            we can tell zlib to skip the adler32 check. */
 327         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 328             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 329             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 330
 331                 wbits = -((data_in[0] >> 4) + 8);
 332                 workspace->strm.next_in += 2;
 333                 workspace->strm.avail_in -= 2;
 334         }
 335
 336         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 337                 pr_warn("BTRFS: inflateInit failed\n");
 338                 return -EIO;
 339         }
 340
 341         while (bytes_left > 0) {
 342                 unsigned long buf_start;
 343                 unsigned long buf_offset;
 344                 unsigned long bytes;
 345
 346                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 347                 if (ret != Z_OK && ret != Z_STREAM_END)
 348                         break;
 349
 350                 buf_start = total_out;
 351                 total_out = workspace->strm.total_out;
 352
 353                 if (total_out == buf_start) {
 354                         ret = -EIO;
 355                         break;
 356                 }
 357
 358                 if (total_out <= start_byte)
 359                         goto next;
 360
 361                 if (total_out > start_byte && buf_start < start_byte)
 362                         buf_offset = start_byte - buf_start;
 363                 else
 364                         buf_offset = 0;
 365
 366                 bytes = min(PAGE_SIZE - pg_offset,
 367                             PAGE_SIZE - buf_offset);
 368                 bytes = min(bytes, bytes_left);
 369
 370                 kaddr = kmap_atomic(dest_page);
 371                 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
 372                 kunmap_atomic(kaddr);
 373
 374                 pg_offset += bytes;
 375                 bytes_left -= bytes;
 376 next:
 377                 workspace->strm.next_out = workspace->buf;
 378                 workspace->strm.avail_out = PAGE_SIZE;
 379         }
 380
 381         if (ret != Z_STREAM_END && bytes_left != 0)
 382                 ret = -EIO;
 383         else
 384                 ret = 0;
 385
 386         zlib_inflateEnd(&workspace->strm);
 387
 388         /*
 389          * this should only happen if zlib returned fewer bytes than we
 390          * expected.  btrfs_get_block is responsible for zeroing from the
 391          * end of the inline extent (destlen) to the end of the page
 392          */
 393         if (pg_offset < destlen) {
 394                 kaddr = kmap_atomic(dest_page);
 395                 memset(kaddr + pg_offset, 0, destlen - pg_offset);
 396                 kunmap_atomic(kaddr);
 397         }
 398         return ret;
 399 }
 400
 401 const struct btrfs_compress_op btrfs_zlib_compress = {
 402         .workspace_manager      = &wsm,
 403         .max_level              = 9,
 404         .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,
 405 };