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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 strm;
37 char *buf;
38 struct list_head list;
39};
40
41static void zlib_free_workspace(struct list_head *ws)
42{
43 struct workspace *workspace = list_entry(ws, struct workspace, list);
44
45 vfree(workspace->strm.workspace);
46 kfree(workspace->buf);
47 kfree(workspace);
48}
49
50static struct list_head *zlib_alloc_workspace(void)
51{
52 struct workspace *workspace;
53 int workspacesize;
54
55 workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
56 if (!workspace)
57 return ERR_PTR(-ENOMEM);
58
59 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
60 zlib_inflate_workspacesize());
61 workspace->strm.workspace = vmalloc(workspacesize);
62 workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
63 if (!workspace->strm.workspace || !workspace->buf)
64 goto fail;
65
66 INIT_LIST_HEAD(&workspace->list);
67
68 return &workspace->list;
69fail:
70 zlib_free_workspace(&workspace->list);
71 return ERR_PTR(-ENOMEM);
72}
73
74static int zlib_compress_pages(struct list_head *ws,
75 struct address_space *mapping,
76 u64 start, unsigned long len,
77 struct page **pages,
78 unsigned long nr_dest_pages,
79 unsigned long *out_pages,
80 unsigned long *total_in,
81 unsigned long *total_out,
82 unsigned long max_out)
83{
84 struct workspace *workspace = list_entry(ws, struct workspace, list);
85 int ret;
86 char *data_in;
87 char *cpage_out;
88 int nr_pages = 0;
89 struct page *in_page = NULL;
90 struct page *out_page = NULL;
91 unsigned long bytes_left;
92
93 *out_pages = 0;
94 *total_out = 0;
95 *total_in = 0;
96
97 if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
98 printk(KERN_WARNING "BTRFS: deflateInit failed\n");
99 ret = -EIO;
100 goto out;
101 }
102
103 workspace->strm.total_in = 0;
104 workspace->strm.total_out = 0;
105
106 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
107 data_in = kmap(in_page);
108
109 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
110 if (out_page == NULL) {
111 ret = -ENOMEM;
112 goto out;
113 }
114 cpage_out = kmap(out_page);
115 pages[0] = out_page;
116 nr_pages = 1;
117
118 workspace->strm.next_in = data_in;
119 workspace->strm.next_out = cpage_out;
120 workspace->strm.avail_out = PAGE_SIZE;
121 workspace->strm.avail_in = min(len, PAGE_SIZE);
122
123 while (workspace->strm.total_in < len) {
124 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
125 if (ret != Z_OK) {
126 printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
127 ret);
128 zlib_deflateEnd(&workspace->strm);
129 ret = -EIO;
130 goto out;
131 }
132
133 /* we're making it bigger, give up */
134 if (workspace->strm.total_in > 8192 &&
135 workspace->strm.total_in <
136 workspace->strm.total_out) {
137 ret = -E2BIG;
138 goto out;
139 }
140 /* we need another page for writing out. Test this
141 * before the total_in so we will pull in a new page for
142 * the stream end if required
143 */
144 if (workspace->strm.avail_out == 0) {
145 kunmap(out_page);
146 if (nr_pages == nr_dest_pages) {
147 out_page = NULL;
148 ret = -E2BIG;
149 goto out;
150 }
151 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
152 if (out_page == NULL) {
153 ret = -ENOMEM;
154 goto out;
155 }
156 cpage_out = kmap(out_page);
157 pages[nr_pages] = out_page;
158 nr_pages++;
159 workspace->strm.avail_out = PAGE_SIZE;
160 workspace->strm.next_out = cpage_out;
161 }
162 /* we're all done */
163 if (workspace->strm.total_in >= len)
164 break;
165
166 /* we've read in a full page, get a new one */
167 if (workspace->strm.avail_in == 0) {
168 if (workspace->strm.total_out > max_out)
169 break;
170
171 bytes_left = len - workspace->strm.total_in;
172 kunmap(in_page);
173 put_page(in_page);
174
175 start += PAGE_SIZE;
176 in_page = find_get_page(mapping,
177 start >> PAGE_SHIFT);
178 data_in = kmap(in_page);
179 workspace->strm.avail_in = min(bytes_left,
180 PAGE_SIZE);
181 workspace->strm.next_in = data_in;
182 }
183 }
184 workspace->strm.avail_in = 0;
185 ret = zlib_deflate(&workspace->strm, Z_FINISH);
186 zlib_deflateEnd(&workspace->strm);
187
188 if (ret != Z_STREAM_END) {
189 ret = -EIO;
190 goto out;
191 }
192
193 if (workspace->strm.total_out >= workspace->strm.total_in) {
194 ret = -E2BIG;
195 goto out;
196 }
197
198 ret = 0;
199 *total_out = workspace->strm.total_out;
200 *total_in = workspace->strm.total_in;
201out:
202 *out_pages = nr_pages;
203 if (out_page)
204 kunmap(out_page);
205
206 if (in_page) {
207 kunmap(in_page);
208 put_page(in_page);
209 }
210 return ret;
211}
212
213static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
214 u64 disk_start,
215 struct bio_vec *bvec,
216 int vcnt,
217 size_t srclen)
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 unsigned long page_out_index = 0;
226 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
227 unsigned long buf_start;
228 unsigned long pg_offset;
229
230 data_in = kmap(pages_in[page_in_index]);
231 workspace->strm.next_in = data_in;
232 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
233 workspace->strm.total_in = 0;
234
235 workspace->strm.total_out = 0;
236 workspace->strm.next_out = workspace->buf;
237 workspace->strm.avail_out = PAGE_SIZE;
238 pg_offset = 0;
239
240 /* If it's deflate, and it's got no preset dictionary, then
241 we can tell zlib to skip the adler32 check. */
242 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
243 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
244 !(((data_in[0]<<8) + data_in[1]) % 31)) {
245
246 wbits = -((data_in[0] >> 4) + 8);
247 workspace->strm.next_in += 2;
248 workspace->strm.avail_in -= 2;
249 }
250
251 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
252 printk(KERN_WARNING "BTRFS: inflateInit failed\n");
253 return -EIO;
254 }
255 while (workspace->strm.total_in < srclen) {
256 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
257 if (ret != Z_OK && ret != Z_STREAM_END)
258 break;
259
260 buf_start = total_out;
261 total_out = workspace->strm.total_out;
262
263 /* we didn't make progress in this inflate call, we're done */
264 if (buf_start == total_out)
265 break;
266
267 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
268 total_out, disk_start,
269 bvec, vcnt,
270 &page_out_index, &pg_offset);
271 if (ret2 == 0) {
272 ret = 0;
273 goto done;
274 }
275
276 workspace->strm.next_out = workspace->buf;
277 workspace->strm.avail_out = PAGE_SIZE;
278
279 if (workspace->strm.avail_in == 0) {
280 unsigned long tmp;
281 kunmap(pages_in[page_in_index]);
282 page_in_index++;
283 if (page_in_index >= total_pages_in) {
284 data_in = NULL;
285 break;
286 }
287 data_in = kmap(pages_in[page_in_index]);
288 workspace->strm.next_in = data_in;
289 tmp = srclen - workspace->strm.total_in;
290 workspace->strm.avail_in = min(tmp,
291 PAGE_SIZE);
292 }
293 }
294 if (ret != Z_STREAM_END)
295 ret = -EIO;
296 else
297 ret = 0;
298done:
299 zlib_inflateEnd(&workspace->strm);
300 if (data_in)
301 kunmap(pages_in[page_in_index]);
302 if (!ret)
303 btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
304 return ret;
305}
306
307static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
308 struct page *dest_page,
309 unsigned long start_byte,
310 size_t srclen, 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 printk(KERN_WARNING "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;
381next:
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
406const struct btrfs_compress_op btrfs_zlib_compress = {
407 .alloc_workspace = zlib_alloc_workspace,
408 .free_workspace = zlib_free_workspace,
409 .compress_pages = zlib_compress_pages,
410 .decompress_biovec = zlib_decompress_biovec,
411 .decompress = zlib_decompress,
412};
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};