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 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(&wsm, 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_put_workspace(struct list_head *ws)
  43 {
  44         btrfs_put_workspace(&wsm, ws);
  45 }
  46
  47 void zlib_free_workspace(struct list_head *ws)
  48 {
  49         struct workspace *workspace = list_entry(ws, struct workspace, list);
  50
  51         kvfree(workspace->strm.workspace);
  52         kfree(workspace->buf);
  53         kfree(workspace);
  54 }
  55
  56 struct list_head *zlib_alloc_workspace(unsigned int level)
  57 {
  58         struct workspace *workspace;
  59         int workspacesize;
  60
  61         workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
  62         if (!workspace)
  63                 return ERR_PTR(-ENOMEM);
  64
  65         workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
  66                         zlib_inflate_workspacesize());
  67         workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
  68         workspace->level = level;
  69         workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  70         if (!workspace->strm.workspace || !workspace->buf)
  71                 goto fail;
  72
  73         INIT_LIST_HEAD(&workspace->list);
  74
  75         return &workspace->list;
  76 fail:
  77         zlib_free_workspace(&workspace->list);
  78         return ERR_PTR(-ENOMEM);
  79 }
  80
  81 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
  82                 u64 start, struct page **pages, unsigned long *out_pages,
  83                 unsigned long *total_in, unsigned long *total_out)
  84 {
  85         struct workspace *workspace = list_entry(ws, struct workspace, list);
  86         int ret;
  87         char *data_in;
  88         char *cpage_out;
  89         int nr_pages = 0;
  90         struct page *in_page = NULL;
  91         struct page *out_page = NULL;
  92         unsigned long bytes_left;
  93         unsigned long len = *total_out;
  94         unsigned long nr_dest_pages = *out_pages;
  95         const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
  96
  97         *out_pages = 0;
  98         *total_out = 0;
  99         *total_in = 0;
 100
 101         if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
 102                 pr_warn("BTRFS: deflateInit failed\n");
 103                 ret = -EIO;
 104                 goto out;
 105         }
 106
 107         workspace->strm.total_in = 0;
 108         workspace->strm.total_out = 0;
 109
 110         in_page = find_get_page(mapping, start >> PAGE_SHIFT);
 111         data_in = kmap(in_page);
 112
 113         out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 114         if (out_page == NULL) {
 115                 ret = -ENOMEM;
 116                 goto out;
 117         }
 118         cpage_out = kmap(out_page);
 119         pages[0] = out_page;
 120         nr_pages = 1;
 121
 122         workspace->strm.next_in = data_in;
 123         workspace->strm.next_out = cpage_out;
 124         workspace->strm.avail_out = PAGE_SIZE;
 125         workspace->strm.avail_in = min(len, PAGE_SIZE);
 126
 127         while (workspace->strm.total_in < len) {
 128                 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
 129                 if (ret != Z_OK) {
 130                         pr_debug("BTRFS: deflate in loop returned %d\n",
 131                                ret);
 132                         zlib_deflateEnd(&workspace->strm);
 133                         ret = -EIO;
 134                         goto out;
 135                 }
 136
 137                 /* we're making it bigger, give up */
 138                 if (workspace->strm.total_in > 8192 &&
 139                     workspace->strm.total_in <
 140                     workspace->strm.total_out) {
 141                         ret = -E2BIG;
 142                         goto out;
 143                 }
 144                 /* we need another page for writing out.  Test this
 145                  * before the total_in so we will pull in a new page for
 146                  * the stream end if required
 147                  */
 148                 if (workspace->strm.avail_out == 0) {
 149                         kunmap(out_page);
 150                         if (nr_pages == nr_dest_pages) {
 151                                 out_page = NULL;
 152                                 ret = -E2BIG;
 153                                 goto out;
 154                         }
 155                         out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 156                         if (out_page == NULL) {
 157                                 ret = -ENOMEM;
 158                                 goto out;
 159                         }
 160                         cpage_out = kmap(out_page);
 161                         pages[nr_pages] = out_page;
 162                         nr_pages++;
 163                         workspace->strm.avail_out = PAGE_SIZE;
 164                         workspace->strm.next_out = cpage_out;
 165                 }
 166                 /* we're all done */
 167                 if (workspace->strm.total_in >= len)
 168                         break;
 169
 170                 /* we've read in a full page, get a new one */
 171                 if (workspace->strm.avail_in == 0) {
 172                         if (workspace->strm.total_out > max_out)
 173                                 break;
 174
 175                         bytes_left = len - workspace->strm.total_in;
 176                         kunmap(in_page);
 177                         put_page(in_page);
 178
 179                         start += PAGE_SIZE;
 180                         in_page = find_get_page(mapping,
 181                                                 start >> PAGE_SHIFT);
 182                         data_in = kmap(in_page);
 183                         workspace->strm.avail_in = min(bytes_left,
 184                                                            PAGE_SIZE);
 185                         workspace->strm.next_in = data_in;
 186                 }
 187         }
 188         workspace->strm.avail_in = 0;
 189         ret = zlib_deflate(&workspace->strm, Z_FINISH);
 190         zlib_deflateEnd(&workspace->strm);
 191
 192         if (ret != Z_STREAM_END) {
 193                 ret = -EIO;
 194                 goto out;
 195         }
 196
 197         if (workspace->strm.total_out >= workspace->strm.total_in) {
 198                 ret = -E2BIG;
 199                 goto out;
 200         }
 201
 202         ret = 0;
 203         *total_out = workspace->strm.total_out;
 204         *total_in = workspace->strm.total_in;
 205 out:
 206         *out_pages = nr_pages;
 207         if (out_page)
 208                 kunmap(out_page);
 209
 210         if (in_page) {
 211                 kunmap(in_page);
 212                 put_page(in_page);
 213         }
 214         return ret;
 215 }
 216
 217 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 218 {
 219         struct workspace *workspace = list_entry(ws, struct workspace, list);
 220         int ret = 0, ret2;
 221         int wbits = MAX_WBITS;
 222         char *data_in;
 223         size_t total_out = 0;
 224         unsigned long page_in_index = 0;
 225         size_t srclen = cb->compressed_len;
 226         unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 227         unsigned long buf_start;
 228         struct page **pages_in = cb->compressed_pages;
 229         u64 disk_start = cb->start;
 230         struct bio *orig_bio = cb->orig_bio;
 231
 232         data_in = kmap(pages_in[page_in_index]);
 233         workspace->strm.next_in = data_in;
 234         workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 235         workspace->strm.total_in = 0;
 236
 237         workspace->strm.total_out = 0;
 238         workspace->strm.next_out = workspace->buf;
 239         workspace->strm.avail_out = PAGE_SIZE;
 240
 241         /* If it's deflate, and it's got no preset dictionary, then
 242            we can tell zlib to skip the adler32 check. */
 243         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 244             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 245             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 246
 247                 wbits = -((data_in[0] >> 4) + 8);
 248                 workspace->strm.next_in += 2;
 249                 workspace->strm.avail_in -= 2;
 250         }
 251
 252         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 253                 pr_warn("BTRFS: inflateInit failed\n");
 254                 kunmap(pages_in[page_in_index]);
 255                 return -EIO;
 256         }
 257         while (workspace->strm.total_in < srclen) {
 258                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 259                 if (ret != Z_OK && ret != Z_STREAM_END)
 260                         break;
 261
 262                 buf_start = total_out;
 263                 total_out = workspace->strm.total_out;
 264
 265                 /* we didn't make progress in this inflate call, we're done */
 266                 if (buf_start == total_out)
 267                         break;
 268
 269                 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
 270                                                  total_out, disk_start,
 271                                                  orig_bio);
 272                 if (ret2 == 0) {
 273                         ret = 0;
 274                         goto done;
 275                 }
 276
 277                 workspace->strm.next_out = workspace->buf;
 278                 workspace->strm.avail_out = PAGE_SIZE;
 279
 280                 if (workspace->strm.avail_in == 0) {
 281                         unsigned long tmp;
 282                         kunmap(pages_in[page_in_index]);
 283                         page_in_index++;
 284                         if (page_in_index >= total_pages_in) {
 285                                 data_in = NULL;
 286                                 break;
 287                         }
 288                         data_in = kmap(pages_in[page_in_index]);
 289                         workspace->strm.next_in = data_in;
 290                         tmp = srclen - workspace->strm.total_in;
 291                         workspace->strm.avail_in = min(tmp,
 292                                                            PAGE_SIZE);
 293                 }
 294         }
 295         if (ret != Z_STREAM_END)
 296                 ret = -EIO;
 297         else
 298                 ret = 0;
 299 done:
 300         zlib_inflateEnd(&workspace->strm);
 301         if (data_in)
 302                 kunmap(pages_in[page_in_index]);
 303         if (!ret)
 304                 zero_fill_bio(orig_bio);
 305         return ret;
 306 }
 307
 308 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 309                 struct page *dest_page, unsigned long start_byte, size_t srclen,
 310                 size_t destlen)
 311 {
 312         struct workspace *workspace = list_entry(ws, struct workspace, list);
 313         int ret = 0;
 314         int wbits = MAX_WBITS;
 315         unsigned long bytes_left;
 316         unsigned long total_out = 0;
 317         unsigned long pg_offset = 0;
 318         char *kaddr;
 319
 320         destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 321         bytes_left = destlen;
 322
 323         workspace->strm.next_in = data_in;
 324         workspace->strm.avail_in = srclen;
 325         workspace->strm.total_in = 0;
 326
 327         workspace->strm.next_out = workspace->buf;
 328         workspace->strm.avail_out = PAGE_SIZE;
 329         workspace->strm.total_out = 0;
 330         /* If it's deflate, and it's got no preset dictionary, then
 331            we can tell zlib to skip the adler32 check. */
 332         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 333             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 334             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 335
 336                 wbits = -((data_in[0] >> 4) + 8);
 337                 workspace->strm.next_in += 2;
 338                 workspace->strm.avail_in -= 2;
 339         }
 340
 341         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 342                 pr_warn("BTRFS: inflateInit failed\n");
 343                 return -EIO;
 344         }
 345
 346         while (bytes_left > 0) {
 347                 unsigned long buf_start;
 348                 unsigned long buf_offset;
 349                 unsigned long bytes;
 350
 351                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 352                 if (ret != Z_OK && ret != Z_STREAM_END)
 353                         break;
 354
 355                 buf_start = total_out;
 356                 total_out = workspace->strm.total_out;
 357
 358                 if (total_out == buf_start) {
 359                         ret = -EIO;
 360                         break;
 361                 }
 362
 363                 if (total_out <= start_byte)
 364                         goto next;
 365
 366                 if (total_out > start_byte && buf_start < start_byte)
 367                         buf_offset = start_byte - buf_start;
 368                 else
 369                         buf_offset = 0;
 370
 371                 bytes = min(PAGE_SIZE - pg_offset,
 372                             PAGE_SIZE - buf_offset);
 373                 bytes = min(bytes, bytes_left);
 374
 375                 kaddr = kmap_atomic(dest_page);
 376                 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
 377                 kunmap_atomic(kaddr);
 378
 379                 pg_offset += bytes;
 380                 bytes_left -= bytes;
 381 next:
 382                 workspace->strm.next_out = workspace->buf;
 383                 workspace->strm.avail_out = PAGE_SIZE;
 384         }
 385
 386         if (ret != Z_STREAM_END && bytes_left != 0)
 387                 ret = -EIO;
 388         else
 389                 ret = 0;
 390
 391         zlib_inflateEnd(&workspace->strm);
 392
 393         /*
 394          * this should only happen if zlib returned fewer bytes than we
 395          * expected.  btrfs_get_block is responsible for zeroing from the
 396          * end of the inline extent (destlen) to the end of the page
 397          */
 398         if (pg_offset < destlen) {
 399                 kaddr = kmap_atomic(dest_page);
 400                 memset(kaddr + pg_offset, 0, destlen - pg_offset);
 401                 kunmap_atomic(kaddr);
 402         }
 403         return ret;
 404 }
 405
 406 const struct btrfs_compress_op btrfs_zlib_compress = {
 407         .workspace_manager      = &wsm,
 408         .get_workspace          = zlib_get_workspace,
 409         .put_workspace          = zlib_put_workspace,
 410         .alloc_workspace        = zlib_alloc_workspace,
 411         .free_workspace         = zlib_free_workspace,
 412         .max_level              = 9,
 413         .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,
 414 };