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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
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 = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN);
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 = NULL;
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 = btrfs_alloc_compr_page();
125 if (out_page == NULL) {
126 ret = -ENOMEM;
127 goto out;
128 }
129 cpage_out = page_address(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 (data_in) {
152 kunmap_local(data_in);
153 put_page(in_page);
154 }
155 in_page = find_get_page(mapping,
156 start >> PAGE_SHIFT);
157 data_in = kmap_local_page(in_page);
158 copy_page(workspace->buf + i * PAGE_SIZE,
159 data_in);
160 start += PAGE_SIZE;
161 }
162 workspace->strm.next_in = workspace->buf;
163 } else {
164 if (data_in) {
165 kunmap_local(data_in);
166 put_page(in_page);
167 }
168 in_page = find_get_page(mapping,
169 start >> PAGE_SHIFT);
170 data_in = kmap_local_page(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 if (nr_pages == nr_dest_pages) {
200 ret = -E2BIG;
201 goto out;
202 }
203 out_page = btrfs_alloc_compr_page();
204 if (out_page == NULL) {
205 ret = -ENOMEM;
206 goto out;
207 }
208 cpage_out = page_address(out_page);
209 pages[nr_pages] = out_page;
210 nr_pages++;
211 workspace->strm.avail_out = PAGE_SIZE;
212 workspace->strm.next_out = cpage_out;
213 }
214 /* we're all done */
215 if (workspace->strm.total_in >= len)
216 break;
217 if (workspace->strm.total_out > max_out)
218 break;
219 }
220 workspace->strm.avail_in = 0;
221 /*
222 * Call deflate with Z_FINISH flush parameter providing more output
223 * space but no more input data, until it returns with Z_STREAM_END.
224 */
225 while (ret != Z_STREAM_END) {
226 ret = zlib_deflate(&workspace->strm, Z_FINISH);
227 if (ret == Z_STREAM_END)
228 break;
229 if (ret != Z_OK && ret != Z_BUF_ERROR) {
230 zlib_deflateEnd(&workspace->strm);
231 ret = -EIO;
232 goto out;
233 } else if (workspace->strm.avail_out == 0) {
234 /* get another page for the stream end */
235 if (nr_pages == nr_dest_pages) {
236 ret = -E2BIG;
237 goto out;
238 }
239 out_page = btrfs_alloc_compr_page();
240 if (out_page == NULL) {
241 ret = -ENOMEM;
242 goto out;
243 }
244 cpage_out = page_address(out_page);
245 pages[nr_pages] = out_page;
246 nr_pages++;
247 workspace->strm.avail_out = PAGE_SIZE;
248 workspace->strm.next_out = cpage_out;
249 }
250 }
251 zlib_deflateEnd(&workspace->strm);
252
253 if (workspace->strm.total_out >= workspace->strm.total_in) {
254 ret = -E2BIG;
255 goto out;
256 }
257
258 ret = 0;
259 *total_out = workspace->strm.total_out;
260 *total_in = workspace->strm.total_in;
261out:
262 *out_pages = nr_pages;
263 if (data_in) {
264 kunmap_local(data_in);
265 put_page(in_page);
266 }
267
268 return ret;
269}
270
271int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
272{
273 struct workspace *workspace = list_entry(ws, struct workspace, list);
274 int ret = 0, ret2;
275 int wbits = MAX_WBITS;
276 char *data_in;
277 size_t total_out = 0;
278 unsigned long page_in_index = 0;
279 size_t srclen = cb->compressed_len;
280 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
281 unsigned long buf_start;
282 struct page **pages_in = cb->compressed_pages;
283
284 data_in = kmap_local_page(pages_in[page_in_index]);
285 workspace->strm.next_in = data_in;
286 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
287 workspace->strm.total_in = 0;
288
289 workspace->strm.total_out = 0;
290 workspace->strm.next_out = workspace->buf;
291 workspace->strm.avail_out = workspace->buf_size;
292
293 /* If it's deflate, and it's got no preset dictionary, then
294 we can tell zlib to skip the adler32 check. */
295 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
296 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
297 !(((data_in[0]<<8) + data_in[1]) % 31)) {
298
299 wbits = -((data_in[0] >> 4) + 8);
300 workspace->strm.next_in += 2;
301 workspace->strm.avail_in -= 2;
302 }
303
304 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
305 pr_warn("BTRFS: inflateInit failed\n");
306 kunmap_local(data_in);
307 return -EIO;
308 }
309 while (workspace->strm.total_in < srclen) {
310 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
311 if (ret != Z_OK && ret != Z_STREAM_END)
312 break;
313
314 buf_start = total_out;
315 total_out = workspace->strm.total_out;
316
317 /* we didn't make progress in this inflate call, we're done */
318 if (buf_start == total_out)
319 break;
320
321 ret2 = btrfs_decompress_buf2page(workspace->buf,
322 total_out - buf_start, cb, buf_start);
323 if (ret2 == 0) {
324 ret = 0;
325 goto done;
326 }
327
328 workspace->strm.next_out = workspace->buf;
329 workspace->strm.avail_out = workspace->buf_size;
330
331 if (workspace->strm.avail_in == 0) {
332 unsigned long tmp;
333 kunmap_local(data_in);
334 page_in_index++;
335 if (page_in_index >= total_pages_in) {
336 data_in = NULL;
337 break;
338 }
339 data_in = kmap_local_page(pages_in[page_in_index]);
340 workspace->strm.next_in = data_in;
341 tmp = srclen - workspace->strm.total_in;
342 workspace->strm.avail_in = min(tmp, PAGE_SIZE);
343 }
344 }
345 if (ret != Z_STREAM_END)
346 ret = -EIO;
347 else
348 ret = 0;
349done:
350 zlib_inflateEnd(&workspace->strm);
351 if (data_in)
352 kunmap_local(data_in);
353 return ret;
354}
355
356int zlib_decompress(struct list_head *ws, const u8 *data_in,
357 struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
358 size_t destlen)
359{
360 struct workspace *workspace = list_entry(ws, struct workspace, list);
361 int ret = 0;
362 int wbits = MAX_WBITS;
363 unsigned long to_copy;
364
365 workspace->strm.next_in = data_in;
366 workspace->strm.avail_in = srclen;
367 workspace->strm.total_in = 0;
368
369 workspace->strm.next_out = workspace->buf;
370 workspace->strm.avail_out = workspace->buf_size;
371 workspace->strm.total_out = 0;
372 /* If it's deflate, and it's got no preset dictionary, then
373 we can tell zlib to skip the adler32 check. */
374 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
375 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
376 !(((data_in[0]<<8) + data_in[1]) % 31)) {
377
378 wbits = -((data_in[0] >> 4) + 8);
379 workspace->strm.next_in += 2;
380 workspace->strm.avail_in -= 2;
381 }
382
383 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
384 pr_warn("BTRFS: inflateInit failed\n");
385 return -EIO;
386 }
387
388 /*
389 * Everything (in/out buf) should be at most one sector, there should
390 * be no need to switch any input/output buffer.
391 */
392 ret = zlib_inflate(&workspace->strm, Z_FINISH);
393 to_copy = min(workspace->strm.total_out, destlen);
394 if (ret != Z_STREAM_END)
395 goto out;
396
397 memcpy_to_page(dest_page, dest_pgoff, workspace->buf, to_copy);
398
399out:
400 if (unlikely(to_copy != destlen)) {
401 pr_warn_ratelimited("BTRFS: infalte failed, decompressed=%lu expected=%zu\n",
402 to_copy, destlen);
403 ret = -EIO;
404 } else {
405 ret = 0;
406 }
407
408 zlib_inflateEnd(&workspace->strm);
409
410 if (unlikely(to_copy < destlen))
411 memzero_page(dest_page, dest_pgoff + to_copy, destlen - to_copy);
412 return ret;
413}
414
415const struct btrfs_compress_op btrfs_zlib_compress = {
416 .workspace_manager = &wsm,
417 .max_level = 9,
418 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
419};
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};