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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
23struct workspace {
24 z_stream strm;
25 char *buf;
26 struct list_head list;
27 int level;
28};
29
30static void zlib_free_workspace(struct list_head *ws)
31{
32 struct workspace *workspace = list_entry(ws, struct workspace, list);
33
34 kvfree(workspace->strm.workspace);
35 kfree(workspace->buf);
36 kfree(workspace);
37}
38
39static struct list_head *zlib_alloc_workspace(void)
40{
41 struct workspace *workspace;
42 int workspacesize;
43
44 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
45 if (!workspace)
46 return ERR_PTR(-ENOMEM);
47
48 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
49 zlib_inflate_workspacesize());
50 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
51 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
52 if (!workspace->strm.workspace || !workspace->buf)
53 goto fail;
54
55 INIT_LIST_HEAD(&workspace->list);
56
57 return &workspace->list;
58fail:
59 zlib_free_workspace(&workspace->list);
60 return ERR_PTR(-ENOMEM);
61}
62
63static int zlib_compress_pages(struct list_head *ws,
64 struct address_space *mapping,
65 u64 start,
66 struct page **pages,
67 unsigned long *out_pages,
68 unsigned long *total_in,
69 unsigned long *total_out)
70{
71 struct workspace *workspace = list_entry(ws, struct workspace, list);
72 int ret;
73 char *data_in;
74 char *cpage_out;
75 int nr_pages = 0;
76 struct page *in_page = NULL;
77 struct page *out_page = NULL;
78 unsigned long bytes_left;
79 unsigned long len = *total_out;
80 unsigned long nr_dest_pages = *out_pages;
81 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
82
83 *out_pages = 0;
84 *total_out = 0;
85 *total_in = 0;
86
87 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
88 pr_warn("BTRFS: deflateInit failed\n");
89 ret = -EIO;
90 goto out;
91 }
92
93 workspace->strm.total_in = 0;
94 workspace->strm.total_out = 0;
95
96 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
97 data_in = kmap(in_page);
98
99 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
100 if (out_page == NULL) {
101 ret = -ENOMEM;
102 goto out;
103 }
104 cpage_out = kmap(out_page);
105 pages[0] = out_page;
106 nr_pages = 1;
107
108 workspace->strm.next_in = data_in;
109 workspace->strm.next_out = cpage_out;
110 workspace->strm.avail_out = PAGE_SIZE;
111 workspace->strm.avail_in = min(len, PAGE_SIZE);
112
113 while (workspace->strm.total_in < len) {
114 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
115 if (ret != Z_OK) {
116 pr_debug("BTRFS: deflate in loop returned %d\n",
117 ret);
118 zlib_deflateEnd(&workspace->strm);
119 ret = -EIO;
120 goto out;
121 }
122
123 /* we're making it bigger, give up */
124 if (workspace->strm.total_in > 8192 &&
125 workspace->strm.total_in <
126 workspace->strm.total_out) {
127 ret = -E2BIG;
128 goto out;
129 }
130 /* we need another page for writing out. Test this
131 * before the total_in so we will pull in a new page for
132 * the stream end if required
133 */
134 if (workspace->strm.avail_out == 0) {
135 kunmap(out_page);
136 if (nr_pages == nr_dest_pages) {
137 out_page = NULL;
138 ret = -E2BIG;
139 goto out;
140 }
141 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
142 if (out_page == NULL) {
143 ret = -ENOMEM;
144 goto out;
145 }
146 cpage_out = kmap(out_page);
147 pages[nr_pages] = out_page;
148 nr_pages++;
149 workspace->strm.avail_out = PAGE_SIZE;
150 workspace->strm.next_out = cpage_out;
151 }
152 /* we're all done */
153 if (workspace->strm.total_in >= len)
154 break;
155
156 /* we've read in a full page, get a new one */
157 if (workspace->strm.avail_in == 0) {
158 if (workspace->strm.total_out > max_out)
159 break;
160
161 bytes_left = len - workspace->strm.total_in;
162 kunmap(in_page);
163 put_page(in_page);
164
165 start += PAGE_SIZE;
166 in_page = find_get_page(mapping,
167 start >> PAGE_SHIFT);
168 data_in = kmap(in_page);
169 workspace->strm.avail_in = min(bytes_left,
170 PAGE_SIZE);
171 workspace->strm.next_in = data_in;
172 }
173 }
174 workspace->strm.avail_in = 0;
175 ret = zlib_deflate(&workspace->strm, Z_FINISH);
176 zlib_deflateEnd(&workspace->strm);
177
178 if (ret != Z_STREAM_END) {
179 ret = -EIO;
180 goto out;
181 }
182
183 if (workspace->strm.total_out >= workspace->strm.total_in) {
184 ret = -E2BIG;
185 goto out;
186 }
187
188 ret = 0;
189 *total_out = workspace->strm.total_out;
190 *total_in = workspace->strm.total_in;
191out:
192 *out_pages = nr_pages;
193 if (out_page)
194 kunmap(out_page);
195
196 if (in_page) {
197 kunmap(in_page);
198 put_page(in_page);
199 }
200 return ret;
201}
202
203static int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
204{
205 struct workspace *workspace = list_entry(ws, struct workspace, list);
206 int ret = 0, ret2;
207 int wbits = MAX_WBITS;
208 char *data_in;
209 size_t total_out = 0;
210 unsigned long page_in_index = 0;
211 size_t srclen = cb->compressed_len;
212 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
213 unsigned long buf_start;
214 struct page **pages_in = cb->compressed_pages;
215 u64 disk_start = cb->start;
216 struct bio *orig_bio = cb->orig_bio;
217
218 data_in = kmap(pages_in[page_in_index]);
219 workspace->strm.next_in = data_in;
220 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
221 workspace->strm.total_in = 0;
222
223 workspace->strm.total_out = 0;
224 workspace->strm.next_out = workspace->buf;
225 workspace->strm.avail_out = PAGE_SIZE;
226
227 /* If it's deflate, and it's got no preset dictionary, then
228 we can tell zlib to skip the adler32 check. */
229 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
230 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
231 !(((data_in[0]<<8) + data_in[1]) % 31)) {
232
233 wbits = -((data_in[0] >> 4) + 8);
234 workspace->strm.next_in += 2;
235 workspace->strm.avail_in -= 2;
236 }
237
238 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
239 pr_warn("BTRFS: inflateInit failed\n");
240 kunmap(pages_in[page_in_index]);
241 return -EIO;
242 }
243 while (workspace->strm.total_in < srclen) {
244 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
245 if (ret != Z_OK && ret != Z_STREAM_END)
246 break;
247
248 buf_start = total_out;
249 total_out = workspace->strm.total_out;
250
251 /* we didn't make progress in this inflate call, we're done */
252 if (buf_start == total_out)
253 break;
254
255 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
256 total_out, disk_start,
257 orig_bio);
258 if (ret2 == 0) {
259 ret = 0;
260 goto done;
261 }
262
263 workspace->strm.next_out = workspace->buf;
264 workspace->strm.avail_out = PAGE_SIZE;
265
266 if (workspace->strm.avail_in == 0) {
267 unsigned long tmp;
268 kunmap(pages_in[page_in_index]);
269 page_in_index++;
270 if (page_in_index >= total_pages_in) {
271 data_in = NULL;
272 break;
273 }
274 data_in = kmap(pages_in[page_in_index]);
275 workspace->strm.next_in = data_in;
276 tmp = srclen - workspace->strm.total_in;
277 workspace->strm.avail_in = min(tmp,
278 PAGE_SIZE);
279 }
280 }
281 if (ret != Z_STREAM_END)
282 ret = -EIO;
283 else
284 ret = 0;
285done:
286 zlib_inflateEnd(&workspace->strm);
287 if (data_in)
288 kunmap(pages_in[page_in_index]);
289 if (!ret)
290 zero_fill_bio(orig_bio);
291 return ret;
292}
293
294static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
295 struct page *dest_page,
296 unsigned long start_byte,
297 size_t srclen, size_t destlen)
298{
299 struct workspace *workspace = list_entry(ws, struct workspace, list);
300 int ret = 0;
301 int wbits = MAX_WBITS;
302 unsigned long bytes_left;
303 unsigned long total_out = 0;
304 unsigned long pg_offset = 0;
305 char *kaddr;
306
307 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
308 bytes_left = destlen;
309
310 workspace->strm.next_in = data_in;
311 workspace->strm.avail_in = srclen;
312 workspace->strm.total_in = 0;
313
314 workspace->strm.next_out = workspace->buf;
315 workspace->strm.avail_out = PAGE_SIZE;
316 workspace->strm.total_out = 0;
317 /* If it's deflate, and it's got no preset dictionary, then
318 we can tell zlib to skip the adler32 check. */
319 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
320 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
321 !(((data_in[0]<<8) + data_in[1]) % 31)) {
322
323 wbits = -((data_in[0] >> 4) + 8);
324 workspace->strm.next_in += 2;
325 workspace->strm.avail_in -= 2;
326 }
327
328 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
329 pr_warn("BTRFS: inflateInit failed\n");
330 return -EIO;
331 }
332
333 while (bytes_left > 0) {
334 unsigned long buf_start;
335 unsigned long buf_offset;
336 unsigned long bytes;
337
338 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
339 if (ret != Z_OK && ret != Z_STREAM_END)
340 break;
341
342 buf_start = total_out;
343 total_out = workspace->strm.total_out;
344
345 if (total_out == buf_start) {
346 ret = -EIO;
347 break;
348 }
349
350 if (total_out <= start_byte)
351 goto next;
352
353 if (total_out > start_byte && buf_start < start_byte)
354 buf_offset = start_byte - buf_start;
355 else
356 buf_offset = 0;
357
358 bytes = min(PAGE_SIZE - pg_offset,
359 PAGE_SIZE - buf_offset);
360 bytes = min(bytes, bytes_left);
361
362 kaddr = kmap_atomic(dest_page);
363 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
364 kunmap_atomic(kaddr);
365
366 pg_offset += bytes;
367 bytes_left -= bytes;
368next:
369 workspace->strm.next_out = workspace->buf;
370 workspace->strm.avail_out = PAGE_SIZE;
371 }
372
373 if (ret != Z_STREAM_END && bytes_left != 0)
374 ret = -EIO;
375 else
376 ret = 0;
377
378 zlib_inflateEnd(&workspace->strm);
379
380 /*
381 * this should only happen if zlib returned fewer bytes than we
382 * expected. btrfs_get_block is responsible for zeroing from the
383 * end of the inline extent (destlen) to the end of the page
384 */
385 if (pg_offset < destlen) {
386 kaddr = kmap_atomic(dest_page);
387 memset(kaddr + pg_offset, 0, destlen - pg_offset);
388 kunmap_atomic(kaddr);
389 }
390 return ret;
391}
392
393static void zlib_set_level(struct list_head *ws, unsigned int type)
394{
395 struct workspace *workspace = list_entry(ws, struct workspace, list);
396 unsigned level = (type & 0xF0) >> 4;
397
398 if (level > 9)
399 level = 9;
400
401 workspace->level = level > 0 ? level : 3;
402}
403
404const struct btrfs_compress_op btrfs_zlib_compress = {
405 .alloc_workspace = zlib_alloc_workspace,
406 .free_workspace = zlib_free_workspace,
407 .compress_pages = zlib_compress_pages,
408 .decompress_bio = zlib_decompress_bio,
409 .decompress = zlib_decompress,
410 .set_level = zlib_set_level,
411};
1/*
2 * Copyright (C) 2008 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 *
18 * Based on jffs2 zlib code:
19 * Copyright © 2001-2007 Red Hat, Inc.
20 * Created by David Woodhouse <dwmw2@infradead.org>
21 */
22
23#include <linux/kernel.h>
24#include <linux/slab.h>
25#include <linux/zlib.h>
26#include <linux/zutil.h>
27#include <linux/vmalloc.h>
28#include <linux/init.h>
29#include <linux/err.h>
30#include <linux/sched.h>
31#include <linux/pagemap.h>
32#include <linux/bio.h>
33#include "compression.h"
34
35struct workspace {
36 z_stream inf_strm;
37 z_stream def_strm;
38 char *buf;
39 struct list_head list;
40};
41
42static void zlib_free_workspace(struct list_head *ws)
43{
44 struct workspace *workspace = list_entry(ws, struct workspace, list);
45
46 vfree(workspace->def_strm.workspace);
47 vfree(workspace->inf_strm.workspace);
48 kfree(workspace->buf);
49 kfree(workspace);
50}
51
52static struct list_head *zlib_alloc_workspace(void)
53{
54 struct workspace *workspace;
55
56 workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
57 if (!workspace)
58 return ERR_PTR(-ENOMEM);
59
60 workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize(
61 MAX_WBITS, MAX_MEM_LEVEL));
62 workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
63 workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
64 if (!workspace->def_strm.workspace ||
65 !workspace->inf_strm.workspace || !workspace->buf)
66 goto fail;
67
68 INIT_LIST_HEAD(&workspace->list);
69
70 return &workspace->list;
71fail:
72 zlib_free_workspace(&workspace->list);
73 return ERR_PTR(-ENOMEM);
74}
75
76static int zlib_compress_pages(struct list_head *ws,
77 struct address_space *mapping,
78 u64 start, unsigned long len,
79 struct page **pages,
80 unsigned long nr_dest_pages,
81 unsigned long *out_pages,
82 unsigned long *total_in,
83 unsigned long *total_out,
84 unsigned long max_out)
85{
86 struct workspace *workspace = list_entry(ws, struct workspace, list);
87 int ret;
88 char *data_in;
89 char *cpage_out;
90 int nr_pages = 0;
91 struct page *in_page = NULL;
92 struct page *out_page = NULL;
93 unsigned long bytes_left;
94
95 *out_pages = 0;
96 *total_out = 0;
97 *total_in = 0;
98
99 if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
100 printk(KERN_WARNING "BTRFS: deflateInit failed\n");
101 ret = -1;
102 goto out;
103 }
104
105 workspace->def_strm.total_in = 0;
106 workspace->def_strm.total_out = 0;
107
108 in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
109 data_in = kmap(in_page);
110
111 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
112 if (out_page == NULL) {
113 ret = -1;
114 goto out;
115 }
116 cpage_out = kmap(out_page);
117 pages[0] = out_page;
118 nr_pages = 1;
119
120 workspace->def_strm.next_in = data_in;
121 workspace->def_strm.next_out = cpage_out;
122 workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
123 workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
124
125 while (workspace->def_strm.total_in < len) {
126 ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
127 if (ret != Z_OK) {
128 printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
129 ret);
130 zlib_deflateEnd(&workspace->def_strm);
131 ret = -1;
132 goto out;
133 }
134
135 /* we're making it bigger, give up */
136 if (workspace->def_strm.total_in > 8192 &&
137 workspace->def_strm.total_in <
138 workspace->def_strm.total_out) {
139 ret = -1;
140 goto out;
141 }
142 /* we need another page for writing out. Test this
143 * before the total_in so we will pull in a new page for
144 * the stream end if required
145 */
146 if (workspace->def_strm.avail_out == 0) {
147 kunmap(out_page);
148 if (nr_pages == nr_dest_pages) {
149 out_page = NULL;
150 ret = -1;
151 goto out;
152 }
153 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
154 if (out_page == NULL) {
155 ret = -1;
156 goto out;
157 }
158 cpage_out = kmap(out_page);
159 pages[nr_pages] = out_page;
160 nr_pages++;
161 workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
162 workspace->def_strm.next_out = cpage_out;
163 }
164 /* we're all done */
165 if (workspace->def_strm.total_in >= len)
166 break;
167
168 /* we've read in a full page, get a new one */
169 if (workspace->def_strm.avail_in == 0) {
170 if (workspace->def_strm.total_out > max_out)
171 break;
172
173 bytes_left = len - workspace->def_strm.total_in;
174 kunmap(in_page);
175 page_cache_release(in_page);
176
177 start += PAGE_CACHE_SIZE;
178 in_page = find_get_page(mapping,
179 start >> PAGE_CACHE_SHIFT);
180 data_in = kmap(in_page);
181 workspace->def_strm.avail_in = min(bytes_left,
182 PAGE_CACHE_SIZE);
183 workspace->def_strm.next_in = data_in;
184 }
185 }
186 workspace->def_strm.avail_in = 0;
187 ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
188 zlib_deflateEnd(&workspace->def_strm);
189
190 if (ret != Z_STREAM_END) {
191 ret = -1;
192 goto out;
193 }
194
195 if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
196 ret = -1;
197 goto out;
198 }
199
200 ret = 0;
201 *total_out = workspace->def_strm.total_out;
202 *total_in = workspace->def_strm.total_in;
203out:
204 *out_pages = nr_pages;
205 if (out_page)
206 kunmap(out_page);
207
208 if (in_page) {
209 kunmap(in_page);
210 page_cache_release(in_page);
211 }
212 return ret;
213}
214
215static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
216 u64 disk_start,
217 struct bio_vec *bvec,
218 int vcnt,
219 size_t srclen)
220{
221 struct workspace *workspace = list_entry(ws, struct workspace, list);
222 int ret = 0, ret2;
223 int wbits = MAX_WBITS;
224 char *data_in;
225 size_t total_out = 0;
226 unsigned long page_in_index = 0;
227 unsigned long page_out_index = 0;
228 unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
229 PAGE_CACHE_SIZE;
230 unsigned long buf_start;
231 unsigned long pg_offset;
232
233 data_in = kmap(pages_in[page_in_index]);
234 workspace->inf_strm.next_in = data_in;
235 workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
236 workspace->inf_strm.total_in = 0;
237
238 workspace->inf_strm.total_out = 0;
239 workspace->inf_strm.next_out = workspace->buf;
240 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
241 pg_offset = 0;
242
243 /* If it's deflate, and it's got no preset dictionary, then
244 we can tell zlib to skip the adler32 check. */
245 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
246 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
247 !(((data_in[0]<<8) + data_in[1]) % 31)) {
248
249 wbits = -((data_in[0] >> 4) + 8);
250 workspace->inf_strm.next_in += 2;
251 workspace->inf_strm.avail_in -= 2;
252 }
253
254 if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
255 printk(KERN_WARNING "BTRFS: inflateInit failed\n");
256 return -1;
257 }
258 while (workspace->inf_strm.total_in < srclen) {
259 ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
260 if (ret != Z_OK && ret != Z_STREAM_END)
261 break;
262
263 buf_start = total_out;
264 total_out = workspace->inf_strm.total_out;
265
266 /* we didn't make progress in this inflate call, we're done */
267 if (buf_start == total_out)
268 break;
269
270 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
271 total_out, disk_start,
272 bvec, vcnt,
273 &page_out_index, &pg_offset);
274 if (ret2 == 0) {
275 ret = 0;
276 goto done;
277 }
278
279 workspace->inf_strm.next_out = workspace->buf;
280 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
281
282 if (workspace->inf_strm.avail_in == 0) {
283 unsigned long tmp;
284 kunmap(pages_in[page_in_index]);
285 page_in_index++;
286 if (page_in_index >= total_pages_in) {
287 data_in = NULL;
288 break;
289 }
290 data_in = kmap(pages_in[page_in_index]);
291 workspace->inf_strm.next_in = data_in;
292 tmp = srclen - workspace->inf_strm.total_in;
293 workspace->inf_strm.avail_in = min(tmp,
294 PAGE_CACHE_SIZE);
295 }
296 }
297 if (ret != Z_STREAM_END)
298 ret = -1;
299 else
300 ret = 0;
301done:
302 zlib_inflateEnd(&workspace->inf_strm);
303 if (data_in)
304 kunmap(pages_in[page_in_index]);
305 return ret;
306}
307
308static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
309 struct page *dest_page,
310 unsigned long start_byte,
311 size_t srclen, size_t destlen)
312{
313 struct workspace *workspace = list_entry(ws, struct workspace, list);
314 int ret = 0;
315 int wbits = MAX_WBITS;
316 unsigned long bytes_left = destlen;
317 unsigned long total_out = 0;
318 char *kaddr;
319
320 workspace->inf_strm.next_in = data_in;
321 workspace->inf_strm.avail_in = srclen;
322 workspace->inf_strm.total_in = 0;
323
324 workspace->inf_strm.next_out = workspace->buf;
325 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
326 workspace->inf_strm.total_out = 0;
327 /* If it's deflate, and it's got no preset dictionary, then
328 we can tell zlib to skip the adler32 check. */
329 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
330 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
331 !(((data_in[0]<<8) + data_in[1]) % 31)) {
332
333 wbits = -((data_in[0] >> 4) + 8);
334 workspace->inf_strm.next_in += 2;
335 workspace->inf_strm.avail_in -= 2;
336 }
337
338 if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
339 printk(KERN_WARNING "BTRFS: inflateInit failed\n");
340 return -1;
341 }
342
343 while (bytes_left > 0) {
344 unsigned long buf_start;
345 unsigned long buf_offset;
346 unsigned long bytes;
347 unsigned long pg_offset = 0;
348
349 ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
350 if (ret != Z_OK && ret != Z_STREAM_END)
351 break;
352
353 buf_start = total_out;
354 total_out = workspace->inf_strm.total_out;
355
356 if (total_out == buf_start) {
357 ret = -1;
358 break;
359 }
360
361 if (total_out <= start_byte)
362 goto next;
363
364 if (total_out > start_byte && buf_start < start_byte)
365 buf_offset = start_byte - buf_start;
366 else
367 buf_offset = 0;
368
369 bytes = min(PAGE_CACHE_SIZE - pg_offset,
370 PAGE_CACHE_SIZE - buf_offset);
371 bytes = min(bytes, bytes_left);
372
373 kaddr = kmap_atomic(dest_page);
374 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
375 kunmap_atomic(kaddr);
376
377 pg_offset += bytes;
378 bytes_left -= bytes;
379next:
380 workspace->inf_strm.next_out = workspace->buf;
381 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
382 }
383
384 if (ret != Z_STREAM_END && bytes_left != 0)
385 ret = -1;
386 else
387 ret = 0;
388
389 zlib_inflateEnd(&workspace->inf_strm);
390 return ret;
391}
392
393struct btrfs_compress_op btrfs_zlib_compress = {
394 .alloc_workspace = zlib_alloc_workspace,
395 .free_workspace = zlib_free_workspace,
396 .compress_pages = zlib_compress_pages,
397 .decompress_biovec = zlib_decompress_biovec,
398 .decompress = zlib_decompress,
399};