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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 pr_warn("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 pr_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_bio(struct list_head *ws, struct page **pages_in,
214 u64 disk_start,
215 struct bio *orig_bio,
216 size_t srclen)
217{
218 struct workspace *workspace = list_entry(ws, struct workspace, list);
219 int ret = 0, ret2;
220 int wbits = MAX_WBITS;
221 char *data_in;
222 size_t total_out = 0;
223 unsigned long page_in_index = 0;
224 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
225 unsigned long buf_start;
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;
294done:
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
303static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
304 struct page *dest_page,
305 unsigned long start_byte,
306 size_t srclen, size_t destlen)
307{
308 struct workspace *workspace = list_entry(ws, struct workspace, list);
309 int ret = 0;
310 int wbits = MAX_WBITS;
311 unsigned long bytes_left;
312 unsigned long total_out = 0;
313 unsigned long pg_offset = 0;
314 char *kaddr;
315
316 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
317 bytes_left = destlen;
318
319 workspace->strm.next_in = data_in;
320 workspace->strm.avail_in = srclen;
321 workspace->strm.total_in = 0;
322
323 workspace->strm.next_out = workspace->buf;
324 workspace->strm.avail_out = PAGE_SIZE;
325 workspace->strm.total_out = 0;
326 /* If it's deflate, and it's got no preset dictionary, then
327 we can tell zlib to skip the adler32 check. */
328 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
329 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
330 !(((data_in[0]<<8) + data_in[1]) % 31)) {
331
332 wbits = -((data_in[0] >> 4) + 8);
333 workspace->strm.next_in += 2;
334 workspace->strm.avail_in -= 2;
335 }
336
337 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
338 pr_warn("BTRFS: inflateInit failed\n");
339 return -EIO;
340 }
341
342 while (bytes_left > 0) {
343 unsigned long buf_start;
344 unsigned long buf_offset;
345 unsigned long bytes;
346
347 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
348 if (ret != Z_OK && ret != Z_STREAM_END)
349 break;
350
351 buf_start = total_out;
352 total_out = workspace->strm.total_out;
353
354 if (total_out == buf_start) {
355 ret = -EIO;
356 break;
357 }
358
359 if (total_out <= start_byte)
360 goto next;
361
362 if (total_out > start_byte && buf_start < start_byte)
363 buf_offset = start_byte - buf_start;
364 else
365 buf_offset = 0;
366
367 bytes = min(PAGE_SIZE - pg_offset,
368 PAGE_SIZE - buf_offset);
369 bytes = min(bytes, bytes_left);
370
371 kaddr = kmap_atomic(dest_page);
372 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
373 kunmap_atomic(kaddr);
374
375 pg_offset += bytes;
376 bytes_left -= bytes;
377next:
378 workspace->strm.next_out = workspace->buf;
379 workspace->strm.avail_out = PAGE_SIZE;
380 }
381
382 if (ret != Z_STREAM_END && bytes_left != 0)
383 ret = -EIO;
384 else
385 ret = 0;
386
387 zlib_inflateEnd(&workspace->strm);
388
389 /*
390 * this should only happen if zlib returned fewer bytes than we
391 * expected. btrfs_get_block is responsible for zeroing from the
392 * end of the inline extent (destlen) to the end of the page
393 */
394 if (pg_offset < destlen) {
395 kaddr = kmap_atomic(dest_page);
396 memset(kaddr + pg_offset, 0, destlen - pg_offset);
397 kunmap_atomic(kaddr);
398 }
399 return ret;
400}
401
402const struct btrfs_compress_op btrfs_zlib_compress = {
403 .alloc_workspace = zlib_alloc_workspace,
404 .free_workspace = zlib_free_workspace,
405 .compress_pages = zlib_compress_pages,
406 .decompress_bio = zlib_decompress_bio,
407 .decompress = zlib_decompress,
408};
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/* workspace buffer size for s390 zlib hardware support */
24#define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
25
26struct workspace {
27 z_stream strm;
28 char *buf;
29 unsigned int buf_size;
30 struct list_head list;
31 int level;
32};
33
34static struct workspace_manager wsm;
35
36struct list_head *zlib_get_workspace(unsigned int level)
37{
38 struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
39 struct workspace *workspace = list_entry(ws, struct workspace, list);
40
41 workspace->level = level;
42
43 return ws;
44}
45
46void zlib_free_workspace(struct list_head *ws)
47{
48 struct workspace *workspace = list_entry(ws, struct workspace, list);
49
50 kvfree(workspace->strm.workspace);
51 kfree(workspace->buf);
52 kfree(workspace);
53}
54
55struct list_head *zlib_alloc_workspace(unsigned int level)
56{
57 struct workspace *workspace;
58 int workspacesize;
59
60 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
61 if (!workspace)
62 return ERR_PTR(-ENOMEM);
63
64 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
65 zlib_inflate_workspacesize());
66 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
67 workspace->level = level;
68 workspace->buf = NULL;
69 /*
70 * In case of s390 zlib hardware support, allocate lager workspace
71 * buffer. If allocator fails, fall back to a single page buffer.
72 */
73 if (zlib_deflate_dfltcc_enabled()) {
74 workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
75 __GFP_NOMEMALLOC | __GFP_NORETRY |
76 __GFP_NOWARN | GFP_NOIO);
77 workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
78 }
79 if (!workspace->buf) {
80 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
81 workspace->buf_size = PAGE_SIZE;
82 }
83 if (!workspace->strm.workspace || !workspace->buf)
84 goto fail;
85
86 INIT_LIST_HEAD(&workspace->list);
87
88 return &workspace->list;
89fail:
90 zlib_free_workspace(&workspace->list);
91 return ERR_PTR(-ENOMEM);
92}
93
94int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
95 u64 start, struct page **pages, unsigned long *out_pages,
96 unsigned long *total_in, unsigned long *total_out)
97{
98 struct workspace *workspace = list_entry(ws, struct workspace, list);
99 int ret;
100 char *data_in;
101 char *cpage_out;
102 int nr_pages = 0;
103 struct page *in_page = NULL;
104 struct page *out_page = NULL;
105 unsigned long bytes_left;
106 unsigned int in_buf_pages;
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 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
125 if (out_page == NULL) {
126 ret = -ENOMEM;
127 goto out;
128 }
129 cpage_out = kmap(out_page);
130 pages[0] = out_page;
131 nr_pages = 1;
132
133 workspace->strm.next_in = workspace->buf;
134 workspace->strm.avail_in = 0;
135 workspace->strm.next_out = cpage_out;
136 workspace->strm.avail_out = PAGE_SIZE;
137
138 while (workspace->strm.total_in < len) {
139 /*
140 * Get next input pages and copy the contents to
141 * the workspace buffer if required.
142 */
143 if (workspace->strm.avail_in == 0) {
144 bytes_left = len - workspace->strm.total_in;
145 in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
146 workspace->buf_size / PAGE_SIZE);
147 if (in_buf_pages > 1) {
148 int i;
149
150 for (i = 0; i < in_buf_pages; i++) {
151 if (in_page) {
152 kunmap(in_page);
153 put_page(in_page);
154 }
155 in_page = find_get_page(mapping,
156 start >> PAGE_SHIFT);
157 data_in = kmap(in_page);
158 memcpy(workspace->buf + i * PAGE_SIZE,
159 data_in, PAGE_SIZE);
160 start += PAGE_SIZE;
161 }
162 workspace->strm.next_in = workspace->buf;
163 } else {
164 if (in_page) {
165 kunmap(in_page);
166 put_page(in_page);
167 }
168 in_page = find_get_page(mapping,
169 start >> PAGE_SHIFT);
170 data_in = kmap(in_page);
171 start += PAGE_SIZE;
172 workspace->strm.next_in = data_in;
173 }
174 workspace->strm.avail_in = min(bytes_left,
175 (unsigned long) workspace->buf_size);
176 }
177
178 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
179 if (ret != Z_OK) {
180 pr_debug("BTRFS: deflate in loop returned %d\n",
181 ret);
182 zlib_deflateEnd(&workspace->strm);
183 ret = -EIO;
184 goto out;
185 }
186
187 /* we're making it bigger, give up */
188 if (workspace->strm.total_in > 8192 &&
189 workspace->strm.total_in <
190 workspace->strm.total_out) {
191 ret = -E2BIG;
192 goto out;
193 }
194 /* we need another page for writing out. Test this
195 * before the total_in so we will pull in a new page for
196 * the stream end if required
197 */
198 if (workspace->strm.avail_out == 0) {
199 kunmap(out_page);
200 if (nr_pages == nr_dest_pages) {
201 out_page = NULL;
202 ret = -E2BIG;
203 goto out;
204 }
205 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
206 if (out_page == NULL) {
207 ret = -ENOMEM;
208 goto out;
209 }
210 cpage_out = kmap(out_page);
211 pages[nr_pages] = out_page;
212 nr_pages++;
213 workspace->strm.avail_out = PAGE_SIZE;
214 workspace->strm.next_out = cpage_out;
215 }
216 /* we're all done */
217 if (workspace->strm.total_in >= len)
218 break;
219 if (workspace->strm.total_out > max_out)
220 break;
221 }
222 workspace->strm.avail_in = 0;
223 /*
224 * Call deflate with Z_FINISH flush parameter providing more output
225 * space but no more input data, until it returns with Z_STREAM_END.
226 */
227 while (ret != Z_STREAM_END) {
228 ret = zlib_deflate(&workspace->strm, Z_FINISH);
229 if (ret == Z_STREAM_END)
230 break;
231 if (ret != Z_OK && ret != Z_BUF_ERROR) {
232 zlib_deflateEnd(&workspace->strm);
233 ret = -EIO;
234 goto out;
235 } else if (workspace->strm.avail_out == 0) {
236 /* get another page for the stream end */
237 kunmap(out_page);
238 if (nr_pages == nr_dest_pages) {
239 out_page = NULL;
240 ret = -E2BIG;
241 goto out;
242 }
243 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
244 if (out_page == NULL) {
245 ret = -ENOMEM;
246 goto out;
247 }
248 cpage_out = kmap(out_page);
249 pages[nr_pages] = out_page;
250 nr_pages++;
251 workspace->strm.avail_out = PAGE_SIZE;
252 workspace->strm.next_out = cpage_out;
253 }
254 }
255 zlib_deflateEnd(&workspace->strm);
256
257 if (workspace->strm.total_out >= workspace->strm.total_in) {
258 ret = -E2BIG;
259 goto out;
260 }
261
262 ret = 0;
263 *total_out = workspace->strm.total_out;
264 *total_in = workspace->strm.total_in;
265out:
266 *out_pages = nr_pages;
267 if (out_page)
268 kunmap(out_page);
269
270 if (in_page) {
271 kunmap(in_page);
272 put_page(in_page);
273 }
274 return ret;
275}
276
277int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
278{
279 struct workspace *workspace = list_entry(ws, struct workspace, list);
280 int ret = 0, ret2;
281 int wbits = MAX_WBITS;
282 char *data_in;
283 size_t total_out = 0;
284 unsigned long page_in_index = 0;
285 size_t srclen = cb->compressed_len;
286 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
287 unsigned long buf_start;
288 struct page **pages_in = cb->compressed_pages;
289 u64 disk_start = cb->start;
290 struct bio *orig_bio = cb->orig_bio;
291
292 data_in = kmap(pages_in[page_in_index]);
293 workspace->strm.next_in = data_in;
294 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
295 workspace->strm.total_in = 0;
296
297 workspace->strm.total_out = 0;
298 workspace->strm.next_out = workspace->buf;
299 workspace->strm.avail_out = workspace->buf_size;
300
301 /* If it's deflate, and it's got no preset dictionary, then
302 we can tell zlib to skip the adler32 check. */
303 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
304 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
305 !(((data_in[0]<<8) + data_in[1]) % 31)) {
306
307 wbits = -((data_in[0] >> 4) + 8);
308 workspace->strm.next_in += 2;
309 workspace->strm.avail_in -= 2;
310 }
311
312 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
313 pr_warn("BTRFS: inflateInit failed\n");
314 kunmap(pages_in[page_in_index]);
315 return -EIO;
316 }
317 while (workspace->strm.total_in < srclen) {
318 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
319 if (ret != Z_OK && ret != Z_STREAM_END)
320 break;
321
322 buf_start = total_out;
323 total_out = workspace->strm.total_out;
324
325 /* we didn't make progress in this inflate call, we're done */
326 if (buf_start == total_out)
327 break;
328
329 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
330 total_out, disk_start,
331 orig_bio);
332 if (ret2 == 0) {
333 ret = 0;
334 goto done;
335 }
336
337 workspace->strm.next_out = workspace->buf;
338 workspace->strm.avail_out = workspace->buf_size;
339
340 if (workspace->strm.avail_in == 0) {
341 unsigned long tmp;
342 kunmap(pages_in[page_in_index]);
343 page_in_index++;
344 if (page_in_index >= total_pages_in) {
345 data_in = NULL;
346 break;
347 }
348 data_in = kmap(pages_in[page_in_index]);
349 workspace->strm.next_in = data_in;
350 tmp = srclen - workspace->strm.total_in;
351 workspace->strm.avail_in = min(tmp,
352 PAGE_SIZE);
353 }
354 }
355 if (ret != Z_STREAM_END)
356 ret = -EIO;
357 else
358 ret = 0;
359done:
360 zlib_inflateEnd(&workspace->strm);
361 if (data_in)
362 kunmap(pages_in[page_in_index]);
363 if (!ret)
364 zero_fill_bio(orig_bio);
365 return ret;
366}
367
368int zlib_decompress(struct list_head *ws, unsigned char *data_in,
369 struct page *dest_page, unsigned long start_byte, size_t srclen,
370 size_t destlen)
371{
372 struct workspace *workspace = list_entry(ws, struct workspace, list);
373 int ret = 0;
374 int wbits = MAX_WBITS;
375 unsigned long bytes_left;
376 unsigned long total_out = 0;
377 unsigned long pg_offset = 0;
378 char *kaddr;
379
380 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
381 bytes_left = destlen;
382
383 workspace->strm.next_in = data_in;
384 workspace->strm.avail_in = srclen;
385 workspace->strm.total_in = 0;
386
387 workspace->strm.next_out = workspace->buf;
388 workspace->strm.avail_out = workspace->buf_size;
389 workspace->strm.total_out = 0;
390 /* If it's deflate, and it's got no preset dictionary, then
391 we can tell zlib to skip the adler32 check. */
392 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
393 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
394 !(((data_in[0]<<8) + data_in[1]) % 31)) {
395
396 wbits = -((data_in[0] >> 4) + 8);
397 workspace->strm.next_in += 2;
398 workspace->strm.avail_in -= 2;
399 }
400
401 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
402 pr_warn("BTRFS: inflateInit failed\n");
403 return -EIO;
404 }
405
406 while (bytes_left > 0) {
407 unsigned long buf_start;
408 unsigned long buf_offset;
409 unsigned long bytes;
410
411 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
412 if (ret != Z_OK && ret != Z_STREAM_END)
413 break;
414
415 buf_start = total_out;
416 total_out = workspace->strm.total_out;
417
418 if (total_out == buf_start) {
419 ret = -EIO;
420 break;
421 }
422
423 if (total_out <= start_byte)
424 goto next;
425
426 if (total_out > start_byte && buf_start < start_byte)
427 buf_offset = start_byte - buf_start;
428 else
429 buf_offset = 0;
430
431 bytes = min(PAGE_SIZE - pg_offset,
432 PAGE_SIZE - (buf_offset % PAGE_SIZE));
433 bytes = min(bytes, bytes_left);
434
435 kaddr = kmap_atomic(dest_page);
436 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
437 kunmap_atomic(kaddr);
438
439 pg_offset += bytes;
440 bytes_left -= bytes;
441next:
442 workspace->strm.next_out = workspace->buf;
443 workspace->strm.avail_out = workspace->buf_size;
444 }
445
446 if (ret != Z_STREAM_END && bytes_left != 0)
447 ret = -EIO;
448 else
449 ret = 0;
450
451 zlib_inflateEnd(&workspace->strm);
452
453 /*
454 * this should only happen if zlib returned fewer bytes than we
455 * expected. btrfs_get_block is responsible for zeroing from the
456 * end of the inline extent (destlen) to the end of the page
457 */
458 if (pg_offset < destlen) {
459 kaddr = kmap_atomic(dest_page);
460 memset(kaddr + pg_offset, 0, destlen - pg_offset);
461 kunmap_atomic(kaddr);
462 }
463 return ret;
464}
465
466const struct btrfs_compress_op btrfs_zlib_compress = {
467 .workspace_manager = &wsm,
468 .max_level = 9,
469 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
470};