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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 struct workspace_manager wsm;
31
32static void zlib_init_workspace_manager(void)
33{
34 btrfs_init_workspace_manager(&wsm, &btrfs_zlib_compress);
35}
36
37static void zlib_cleanup_workspace_manager(void)
38{
39 btrfs_cleanup_workspace_manager(&wsm);
40}
41
42static struct list_head *zlib_get_workspace(unsigned int level)
43{
44 struct list_head *ws = btrfs_get_workspace(&wsm, level);
45 struct workspace *workspace = list_entry(ws, struct workspace, list);
46
47 workspace->level = level;
48
49 return ws;
50}
51
52static void zlib_put_workspace(struct list_head *ws)
53{
54 btrfs_put_workspace(&wsm, ws);
55}
56
57static void zlib_free_workspace(struct list_head *ws)
58{
59 struct workspace *workspace = list_entry(ws, struct workspace, list);
60
61 kvfree(workspace->strm.workspace);
62 kfree(workspace->buf);
63 kfree(workspace);
64}
65
66static struct list_head *zlib_alloc_workspace(unsigned int level)
67{
68 struct workspace *workspace;
69 int workspacesize;
70
71 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
72 if (!workspace)
73 return ERR_PTR(-ENOMEM);
74
75 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
76 zlib_inflate_workspacesize());
77 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
78 workspace->level = level;
79 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
80 if (!workspace->strm.workspace || !workspace->buf)
81 goto fail;
82
83 INIT_LIST_HEAD(&workspace->list);
84
85 return &workspace->list;
86fail:
87 zlib_free_workspace(&workspace->list);
88 return ERR_PTR(-ENOMEM);
89}
90
91static int zlib_compress_pages(struct list_head *ws,
92 struct address_space *mapping,
93 u64 start,
94 struct page **pages,
95 unsigned long *out_pages,
96 unsigned long *total_in,
97 unsigned long *total_out)
98{
99 struct workspace *workspace = list_entry(ws, struct workspace, list);
100 int ret;
101 char *data_in;
102 char *cpage_out;
103 int nr_pages = 0;
104 struct page *in_page = NULL;
105 struct page *out_page = NULL;
106 unsigned long bytes_left;
107 unsigned long len = *total_out;
108 unsigned long nr_dest_pages = *out_pages;
109 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
110
111 *out_pages = 0;
112 *total_out = 0;
113 *total_in = 0;
114
115 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
116 pr_warn("BTRFS: deflateInit failed\n");
117 ret = -EIO;
118 goto out;
119 }
120
121 workspace->strm.total_in = 0;
122 workspace->strm.total_out = 0;
123
124 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
125 data_in = kmap(in_page);
126
127 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
128 if (out_page == NULL) {
129 ret = -ENOMEM;
130 goto out;
131 }
132 cpage_out = kmap(out_page);
133 pages[0] = out_page;
134 nr_pages = 1;
135
136 workspace->strm.next_in = data_in;
137 workspace->strm.next_out = cpage_out;
138 workspace->strm.avail_out = PAGE_SIZE;
139 workspace->strm.avail_in = min(len, PAGE_SIZE);
140
141 while (workspace->strm.total_in < len) {
142 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
143 if (ret != Z_OK) {
144 pr_debug("BTRFS: deflate in loop returned %d\n",
145 ret);
146 zlib_deflateEnd(&workspace->strm);
147 ret = -EIO;
148 goto out;
149 }
150
151 /* we're making it bigger, give up */
152 if (workspace->strm.total_in > 8192 &&
153 workspace->strm.total_in <
154 workspace->strm.total_out) {
155 ret = -E2BIG;
156 goto out;
157 }
158 /* we need another page for writing out. Test this
159 * before the total_in so we will pull in a new page for
160 * the stream end if required
161 */
162 if (workspace->strm.avail_out == 0) {
163 kunmap(out_page);
164 if (nr_pages == nr_dest_pages) {
165 out_page = NULL;
166 ret = -E2BIG;
167 goto out;
168 }
169 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
170 if (out_page == NULL) {
171 ret = -ENOMEM;
172 goto out;
173 }
174 cpage_out = kmap(out_page);
175 pages[nr_pages] = out_page;
176 nr_pages++;
177 workspace->strm.avail_out = PAGE_SIZE;
178 workspace->strm.next_out = cpage_out;
179 }
180 /* we're all done */
181 if (workspace->strm.total_in >= len)
182 break;
183
184 /* we've read in a full page, get a new one */
185 if (workspace->strm.avail_in == 0) {
186 if (workspace->strm.total_out > max_out)
187 break;
188
189 bytes_left = len - workspace->strm.total_in;
190 kunmap(in_page);
191 put_page(in_page);
192
193 start += PAGE_SIZE;
194 in_page = find_get_page(mapping,
195 start >> PAGE_SHIFT);
196 data_in = kmap(in_page);
197 workspace->strm.avail_in = min(bytes_left,
198 PAGE_SIZE);
199 workspace->strm.next_in = data_in;
200 }
201 }
202 workspace->strm.avail_in = 0;
203 ret = zlib_deflate(&workspace->strm, Z_FINISH);
204 zlib_deflateEnd(&workspace->strm);
205
206 if (ret != Z_STREAM_END) {
207 ret = -EIO;
208 goto out;
209 }
210
211 if (workspace->strm.total_out >= workspace->strm.total_in) {
212 ret = -E2BIG;
213 goto out;
214 }
215
216 ret = 0;
217 *total_out = workspace->strm.total_out;
218 *total_in = workspace->strm.total_in;
219out:
220 *out_pages = nr_pages;
221 if (out_page)
222 kunmap(out_page);
223
224 if (in_page) {
225 kunmap(in_page);
226 put_page(in_page);
227 }
228 return ret;
229}
230
231static int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
232{
233 struct workspace *workspace = list_entry(ws, struct workspace, list);
234 int ret = 0, ret2;
235 int wbits = MAX_WBITS;
236 char *data_in;
237 size_t total_out = 0;
238 unsigned long page_in_index = 0;
239 size_t srclen = cb->compressed_len;
240 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
241 unsigned long buf_start;
242 struct page **pages_in = cb->compressed_pages;
243 u64 disk_start = cb->start;
244 struct bio *orig_bio = cb->orig_bio;
245
246 data_in = kmap(pages_in[page_in_index]);
247 workspace->strm.next_in = data_in;
248 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
249 workspace->strm.total_in = 0;
250
251 workspace->strm.total_out = 0;
252 workspace->strm.next_out = workspace->buf;
253 workspace->strm.avail_out = PAGE_SIZE;
254
255 /* If it's deflate, and it's got no preset dictionary, then
256 we can tell zlib to skip the adler32 check. */
257 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
258 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
259 !(((data_in[0]<<8) + data_in[1]) % 31)) {
260
261 wbits = -((data_in[0] >> 4) + 8);
262 workspace->strm.next_in += 2;
263 workspace->strm.avail_in -= 2;
264 }
265
266 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
267 pr_warn("BTRFS: inflateInit failed\n");
268 kunmap(pages_in[page_in_index]);
269 return -EIO;
270 }
271 while (workspace->strm.total_in < srclen) {
272 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
273 if (ret != Z_OK && ret != Z_STREAM_END)
274 break;
275
276 buf_start = total_out;
277 total_out = workspace->strm.total_out;
278
279 /* we didn't make progress in this inflate call, we're done */
280 if (buf_start == total_out)
281 break;
282
283 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
284 total_out, disk_start,
285 orig_bio);
286 if (ret2 == 0) {
287 ret = 0;
288 goto done;
289 }
290
291 workspace->strm.next_out = workspace->buf;
292 workspace->strm.avail_out = PAGE_SIZE;
293
294 if (workspace->strm.avail_in == 0) {
295 unsigned long tmp;
296 kunmap(pages_in[page_in_index]);
297 page_in_index++;
298 if (page_in_index >= total_pages_in) {
299 data_in = NULL;
300 break;
301 }
302 data_in = kmap(pages_in[page_in_index]);
303 workspace->strm.next_in = data_in;
304 tmp = srclen - workspace->strm.total_in;
305 workspace->strm.avail_in = min(tmp,
306 PAGE_SIZE);
307 }
308 }
309 if (ret != Z_STREAM_END)
310 ret = -EIO;
311 else
312 ret = 0;
313done:
314 zlib_inflateEnd(&workspace->strm);
315 if (data_in)
316 kunmap(pages_in[page_in_index]);
317 if (!ret)
318 zero_fill_bio(orig_bio);
319 return ret;
320}
321
322static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
323 struct page *dest_page,
324 unsigned long start_byte,
325 size_t srclen, size_t destlen)
326{
327 struct workspace *workspace = list_entry(ws, struct workspace, list);
328 int ret = 0;
329 int wbits = MAX_WBITS;
330 unsigned long bytes_left;
331 unsigned long total_out = 0;
332 unsigned long pg_offset = 0;
333 char *kaddr;
334
335 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
336 bytes_left = destlen;
337
338 workspace->strm.next_in = data_in;
339 workspace->strm.avail_in = srclen;
340 workspace->strm.total_in = 0;
341
342 workspace->strm.next_out = workspace->buf;
343 workspace->strm.avail_out = PAGE_SIZE;
344 workspace->strm.total_out = 0;
345 /* If it's deflate, and it's got no preset dictionary, then
346 we can tell zlib to skip the adler32 check. */
347 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
348 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
349 !(((data_in[0]<<8) + data_in[1]) % 31)) {
350
351 wbits = -((data_in[0] >> 4) + 8);
352 workspace->strm.next_in += 2;
353 workspace->strm.avail_in -= 2;
354 }
355
356 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
357 pr_warn("BTRFS: inflateInit failed\n");
358 return -EIO;
359 }
360
361 while (bytes_left > 0) {
362 unsigned long buf_start;
363 unsigned long buf_offset;
364 unsigned long bytes;
365
366 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
367 if (ret != Z_OK && ret != Z_STREAM_END)
368 break;
369
370 buf_start = total_out;
371 total_out = workspace->strm.total_out;
372
373 if (total_out == buf_start) {
374 ret = -EIO;
375 break;
376 }
377
378 if (total_out <= start_byte)
379 goto next;
380
381 if (total_out > start_byte && buf_start < start_byte)
382 buf_offset = start_byte - buf_start;
383 else
384 buf_offset = 0;
385
386 bytes = min(PAGE_SIZE - pg_offset,
387 PAGE_SIZE - buf_offset);
388 bytes = min(bytes, bytes_left);
389
390 kaddr = kmap_atomic(dest_page);
391 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
392 kunmap_atomic(kaddr);
393
394 pg_offset += bytes;
395 bytes_left -= bytes;
396next:
397 workspace->strm.next_out = workspace->buf;
398 workspace->strm.avail_out = PAGE_SIZE;
399 }
400
401 if (ret != Z_STREAM_END && bytes_left != 0)
402 ret = -EIO;
403 else
404 ret = 0;
405
406 zlib_inflateEnd(&workspace->strm);
407
408 /*
409 * this should only happen if zlib returned fewer bytes than we
410 * expected. btrfs_get_block is responsible for zeroing from the
411 * end of the inline extent (destlen) to the end of the page
412 */
413 if (pg_offset < destlen) {
414 kaddr = kmap_atomic(dest_page);
415 memset(kaddr + pg_offset, 0, destlen - pg_offset);
416 kunmap_atomic(kaddr);
417 }
418 return ret;
419}
420
421const struct btrfs_compress_op btrfs_zlib_compress = {
422 .init_workspace_manager = zlib_init_workspace_manager,
423 .cleanup_workspace_manager = zlib_cleanup_workspace_manager,
424 .get_workspace = zlib_get_workspace,
425 .put_workspace = zlib_put_workspace,
426 .alloc_workspace = zlib_alloc_workspace,
427 .free_workspace = zlib_free_workspace,
428 .compress_pages = zlib_compress_pages,
429 .decompress_bio = zlib_decompress_bio,
430 .decompress = zlib_decompress,
431 .max_level = 9,
432 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
433};
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};