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 static void zlib_init_workspace_manager(void)
  33 {
  34         btrfs_init_workspace_manager(&wsm, &btrfs_zlib_compress);
  35 }
  36
  37 static void zlib_cleanup_workspace_manager(void)
  38 {
  39         btrfs_cleanup_workspace_manager(&wsm);
  40 }
  41
  42 static struct list_head *zlib_get_workspace(unsigned int level)
  43 {
  44         struct list_head *ws = btrfs_get_workspace(&wsm, level);
  45         struct workspace *workspace = list_entry(ws, struct workspace, list);
  46
  47         workspace->level = level;
  48
  49         return ws;
  50 }
  51
  52 static void zlib_put_workspace(struct list_head *ws)
  53 {
  54         btrfs_put_workspace(&wsm, ws);
  55 }
  56
  57 static void zlib_free_workspace(struct list_head *ws)
  58 {
  59         struct workspace *workspace = list_entry(ws, struct workspace, list);
  60
  61         kvfree(workspace->strm.workspace);
  62         kfree(workspace->buf);
  63         kfree(workspace);
  64 }
  65
  66 static struct list_head *zlib_alloc_workspace(unsigned int level)
  67 {
  68         struct workspace *workspace;
  69         int workspacesize;
  70
  71         workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
  72         if (!workspace)
  73                 return ERR_PTR(-ENOMEM);
  74
  75         workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
  76                         zlib_inflate_workspacesize());
  77         workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
  78         workspace->level = level;
  79         workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  80         if (!workspace->strm.workspace || !workspace->buf)
  81                 goto fail;
  82
  83         INIT_LIST_HEAD(&workspace->list);
  84
  85         return &workspace->list;
  86 fail:
  87         zlib_free_workspace(&workspace->list);
  88         return ERR_PTR(-ENOMEM);
  89 }
  90
  91 static int zlib_compress_pages(struct list_head *ws,
  92                                struct address_space *mapping,
  93                                u64 start,
  94                                struct page **pages,
  95                                unsigned long *out_pages,
  96                                unsigned long *total_in,
  97                                unsigned long *total_out)
  98 {
  99         struct workspace *workspace = list_entry(ws, struct workspace, list);
 100         int ret;
 101         char *data_in;
 102         char *cpage_out;
 103         int nr_pages = 0;
 104         struct page *in_page = NULL;
 105         struct page *out_page = NULL;
 106         unsigned long bytes_left;
 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         in_page = find_get_page(mapping, start >> PAGE_SHIFT);
 125         data_in = kmap(in_page);
 126
 127         out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 128         if (out_page == NULL) {
 129                 ret = -ENOMEM;
 130                 goto out;
 131         }
 132         cpage_out = kmap(out_page);
 133         pages[0] = out_page;
 134         nr_pages = 1;
 135
 136         workspace->strm.next_in = data_in;
 137         workspace->strm.next_out = cpage_out;
 138         workspace->strm.avail_out = PAGE_SIZE;
 139         workspace->strm.avail_in = min(len, PAGE_SIZE);
 140
 141         while (workspace->strm.total_in < len) {
 142                 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
 143                 if (ret != Z_OK) {
 144                         pr_debug("BTRFS: deflate in loop returned %d\n",
 145                                ret);
 146                         zlib_deflateEnd(&workspace->strm);
 147                         ret = -EIO;
 148                         goto out;
 149                 }
 150
 151                 /* we're making it bigger, give up */
 152                 if (workspace->strm.total_in > 8192 &&
 153                     workspace->strm.total_in <
 154                     workspace->strm.total_out) {
 155                         ret = -E2BIG;
 156                         goto out;
 157                 }
 158                 /* we need another page for writing out.  Test this
 159                  * before the total_in so we will pull in a new page for
 160                  * the stream end if required
 161                  */
 162                 if (workspace->strm.avail_out == 0) {
 163                         kunmap(out_page);
 164                         if (nr_pages == nr_dest_pages) {
 165                                 out_page = NULL;
 166                                 ret = -E2BIG;
 167                                 goto out;
 168                         }
 169                         out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 170                         if (out_page == NULL) {
 171                                 ret = -ENOMEM;
 172                                 goto out;
 173                         }
 174                         cpage_out = kmap(out_page);
 175                         pages[nr_pages] = out_page;
 176                         nr_pages++;
 177                         workspace->strm.avail_out = PAGE_SIZE;
 178                         workspace->strm.next_out = cpage_out;
 179                 }
 180                 /* we're all done */
 181                 if (workspace->strm.total_in >= len)
 182                         break;
 183
 184                 /* we've read in a full page, get a new one */
 185                 if (workspace->strm.avail_in == 0) {
 186                         if (workspace->strm.total_out > max_out)
 187                                 break;
 188
 189                         bytes_left = len - workspace->strm.total_in;
 190                         kunmap(in_page);
 191                         put_page(in_page);
 192
 193                         start += PAGE_SIZE;
 194                         in_page = find_get_page(mapping,
 195                                                 start >> PAGE_SHIFT);
 196                         data_in = kmap(in_page);
 197                         workspace->strm.avail_in = min(bytes_left,
 198                                                            PAGE_SIZE);
 199                         workspace->strm.next_in = data_in;
 200                 }
 201         }
 202         workspace->strm.avail_in = 0;
 203         ret = zlib_deflate(&workspace->strm, Z_FINISH);
 204         zlib_deflateEnd(&workspace->strm);
 205
 206         if (ret != Z_STREAM_END) {
 207                 ret = -EIO;
 208                 goto out;
 209         }
 210
 211         if (workspace->strm.total_out >= workspace->strm.total_in) {
 212                 ret = -E2BIG;
 213                 goto out;
 214         }
 215
 216         ret = 0;
 217         *total_out = workspace->strm.total_out;
 218         *total_in = workspace->strm.total_in;
 219 out:
 220         *out_pages = nr_pages;
 221         if (out_page)
 222                 kunmap(out_page);
 223
 224         if (in_page) {
 225                 kunmap(in_page);
 226                 put_page(in_page);
 227         }
 228         return ret;
 229 }
 230
 231 static int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 232 {
 233         struct workspace *workspace = list_entry(ws, struct workspace, list);
 234         int ret = 0, ret2;
 235         int wbits = MAX_WBITS;
 236         char *data_in;
 237         size_t total_out = 0;
 238         unsigned long page_in_index = 0;
 239         size_t srclen = cb->compressed_len;
 240         unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 241         unsigned long buf_start;
 242         struct page **pages_in = cb->compressed_pages;
 243         u64 disk_start = cb->start;
 244         struct bio *orig_bio = cb->orig_bio;
 245
 246         data_in = kmap(pages_in[page_in_index]);
 247         workspace->strm.next_in = data_in;
 248         workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 249         workspace->strm.total_in = 0;
 250
 251         workspace->strm.total_out = 0;
 252         workspace->strm.next_out = workspace->buf;
 253         workspace->strm.avail_out = PAGE_SIZE;
 254
 255         /* If it's deflate, and it's got no preset dictionary, then
 256            we can tell zlib to skip the adler32 check. */
 257         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 258             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 259             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 260
 261                 wbits = -((data_in[0] >> 4) + 8);
 262                 workspace->strm.next_in += 2;
 263                 workspace->strm.avail_in -= 2;
 264         }
 265
 266         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 267                 pr_warn("BTRFS: inflateInit failed\n");
 268                 kunmap(pages_in[page_in_index]);
 269                 return -EIO;
 270         }
 271         while (workspace->strm.total_in < srclen) {
 272                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 273                 if (ret != Z_OK && ret != Z_STREAM_END)
 274                         break;
 275
 276                 buf_start = total_out;
 277                 total_out = workspace->strm.total_out;
 278
 279                 /* we didn't make progress in this inflate call, we're done */
 280                 if (buf_start == total_out)
 281                         break;
 282
 283                 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
 284                                                  total_out, disk_start,
 285                                                  orig_bio);
 286                 if (ret2 == 0) {
 287                         ret = 0;
 288                         goto done;
 289                 }
 290
 291                 workspace->strm.next_out = workspace->buf;
 292                 workspace->strm.avail_out = PAGE_SIZE;
 293
 294                 if (workspace->strm.avail_in == 0) {
 295                         unsigned long tmp;
 296                         kunmap(pages_in[page_in_index]);
 297                         page_in_index++;
 298                         if (page_in_index >= total_pages_in) {
 299                                 data_in = NULL;
 300                                 break;
 301                         }
 302                         data_in = kmap(pages_in[page_in_index]);
 303                         workspace->strm.next_in = data_in;
 304                         tmp = srclen - workspace->strm.total_in;
 305                         workspace->strm.avail_in = min(tmp,
 306                                                            PAGE_SIZE);
 307                 }
 308         }
 309         if (ret != Z_STREAM_END)
 310                 ret = -EIO;
 311         else
 312                 ret = 0;
 313 done:
 314         zlib_inflateEnd(&workspace->strm);
 315         if (data_in)
 316                 kunmap(pages_in[page_in_index]);
 317         if (!ret)
 318                 zero_fill_bio(orig_bio);
 319         return ret;
 320 }
 321
 322 static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 323                            struct page *dest_page,
 324                            unsigned long start_byte,
 325                            size_t srclen, size_t destlen)
 326 {
 327         struct workspace *workspace = list_entry(ws, struct workspace, list);
 328         int ret = 0;
 329         int wbits = MAX_WBITS;
 330         unsigned long bytes_left;
 331         unsigned long total_out = 0;
 332         unsigned long pg_offset = 0;
 333         char *kaddr;
 334
 335         destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 336         bytes_left = destlen;
 337
 338         workspace->strm.next_in = data_in;
 339         workspace->strm.avail_in = srclen;
 340         workspace->strm.total_in = 0;
 341
 342         workspace->strm.next_out = workspace->buf;
 343         workspace->strm.avail_out = PAGE_SIZE;
 344         workspace->strm.total_out = 0;
 345         /* If it's deflate, and it's got no preset dictionary, then
 346            we can tell zlib to skip the adler32 check. */
 347         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 348             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 349             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 350
 351                 wbits = -((data_in[0] >> 4) + 8);
 352                 workspace->strm.next_in += 2;
 353                 workspace->strm.avail_in -= 2;
 354         }
 355
 356         if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 357                 pr_warn("BTRFS: inflateInit failed\n");
 358                 return -EIO;
 359         }
 360
 361         while (bytes_left > 0) {
 362                 unsigned long buf_start;
 363                 unsigned long buf_offset;
 364                 unsigned long bytes;
 365
 366                 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
 367                 if (ret != Z_OK && ret != Z_STREAM_END)
 368                         break;
 369
 370                 buf_start = total_out;
 371                 total_out = workspace->strm.total_out;
 372
 373                 if (total_out == buf_start) {
 374                         ret = -EIO;
 375                         break;
 376                 }
 377
 378                 if (total_out <= start_byte)
 379                         goto next;
 380
 381                 if (total_out > start_byte && buf_start < start_byte)
 382                         buf_offset = start_byte - buf_start;
 383                 else
 384                         buf_offset = 0;
 385
 386                 bytes = min(PAGE_SIZE - pg_offset,
 387                             PAGE_SIZE - buf_offset);
 388                 bytes = min(bytes, bytes_left);
 389
 390                 kaddr = kmap_atomic(dest_page);
 391                 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
 392                 kunmap_atomic(kaddr);
 393
 394                 pg_offset += bytes;
 395                 bytes_left -= bytes;
 396 next:
 397                 workspace->strm.next_out = workspace->buf;
 398                 workspace->strm.avail_out = PAGE_SIZE;
 399         }
 400
 401         if (ret != Z_STREAM_END && bytes_left != 0)
 402                 ret = -EIO;
 403         else
 404                 ret = 0;
 405
 406         zlib_inflateEnd(&workspace->strm);
 407
 408         /*
 409          * this should only happen if zlib returned fewer bytes than we
 410          * expected.  btrfs_get_block is responsible for zeroing from the
 411          * end of the inline extent (destlen) to the end of the page
 412          */
 413         if (pg_offset < destlen) {
 414                 kaddr = kmap_atomic(dest_page);
 415                 memset(kaddr + pg_offset, 0, destlen - pg_offset);
 416                 kunmap_atomic(kaddr);
 417         }
 418         return ret;
 419 }
 420
 421 static unsigned int zlib_set_level(unsigned int level)
 422 {
 423         if (!level)
 424                 return BTRFS_ZLIB_DEFAULT_LEVEL;
 425
 426         return min_t(unsigned int, level, 9);
 427 }
 428
 429 const struct btrfs_compress_op btrfs_zlib_compress = {
 430         .init_workspace_manager = zlib_init_workspace_manager,
 431         .cleanup_workspace_manager = zlib_cleanup_workspace_manager,
 432         .get_workspace          = zlib_get_workspace,
 433         .put_workspace          = zlib_put_workspace,
 434         .alloc_workspace        = zlib_alloc_workspace,
 435         .free_workspace         = zlib_free_workspace,
 436         .compress_pages         = zlib_compress_pages,
 437         .decompress_bio         = zlib_decompress_bio,
 438         .decompress             = zlib_decompress,
 439         .set_level              = zlib_set_level,
 440 };