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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 inf_strm;
37 z_stream def_strm;
38 char *buf;
39 struct list_head list;
40};
41
42static void zlib_free_workspace(struct list_head *ws)
43{
44 struct workspace *workspace = list_entry(ws, struct workspace, list);
45
46 vfree(workspace->def_strm.workspace);
47 vfree(workspace->inf_strm.workspace);
48 kfree(workspace->buf);
49 kfree(workspace);
50}
51
52static struct list_head *zlib_alloc_workspace(void)
53{
54 struct workspace *workspace;
55
56 workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
57 if (!workspace)
58 return ERR_PTR(-ENOMEM);
59
60 workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize(
61 MAX_WBITS, MAX_MEM_LEVEL));
62 workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
63 workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
64 if (!workspace->def_strm.workspace ||
65 !workspace->inf_strm.workspace || !workspace->buf)
66 goto fail;
67
68 INIT_LIST_HEAD(&workspace->list);
69
70 return &workspace->list;
71fail:
72 zlib_free_workspace(&workspace->list);
73 return ERR_PTR(-ENOMEM);
74}
75
76static int zlib_compress_pages(struct list_head *ws,
77 struct address_space *mapping,
78 u64 start, unsigned long len,
79 struct page **pages,
80 unsigned long nr_dest_pages,
81 unsigned long *out_pages,
82 unsigned long *total_in,
83 unsigned long *total_out,
84 unsigned long max_out)
85{
86 struct workspace *workspace = list_entry(ws, struct workspace, list);
87 int ret;
88 char *data_in;
89 char *cpage_out;
90 int nr_pages = 0;
91 struct page *in_page = NULL;
92 struct page *out_page = NULL;
93 unsigned long bytes_left;
94
95 *out_pages = 0;
96 *total_out = 0;
97 *total_in = 0;
98
99 if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
100 printk(KERN_WARNING "deflateInit failed\n");
101 ret = -1;
102 goto out;
103 }
104
105 workspace->def_strm.total_in = 0;
106 workspace->def_strm.total_out = 0;
107
108 in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
109 data_in = kmap(in_page);
110
111 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
112 if (out_page == NULL) {
113 ret = -1;
114 goto out;
115 }
116 cpage_out = kmap(out_page);
117 pages[0] = out_page;
118 nr_pages = 1;
119
120 workspace->def_strm.next_in = data_in;
121 workspace->def_strm.next_out = cpage_out;
122 workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
123 workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
124
125 while (workspace->def_strm.total_in < len) {
126 ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
127 if (ret != Z_OK) {
128 printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
129 ret);
130 zlib_deflateEnd(&workspace->def_strm);
131 ret = -1;
132 goto out;
133 }
134
135 /* we're making it bigger, give up */
136 if (workspace->def_strm.total_in > 8192 &&
137 workspace->def_strm.total_in <
138 workspace->def_strm.total_out) {
139 ret = -1;
140 goto out;
141 }
142 /* we need another page for writing out. Test this
143 * before the total_in so we will pull in a new page for
144 * the stream end if required
145 */
146 if (workspace->def_strm.avail_out == 0) {
147 kunmap(out_page);
148 if (nr_pages == nr_dest_pages) {
149 out_page = NULL;
150 ret = -1;
151 goto out;
152 }
153 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
154 if (out_page == NULL) {
155 ret = -1;
156 goto out;
157 }
158 cpage_out = kmap(out_page);
159 pages[nr_pages] = out_page;
160 nr_pages++;
161 workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
162 workspace->def_strm.next_out = cpage_out;
163 }
164 /* we're all done */
165 if (workspace->def_strm.total_in >= len)
166 break;
167
168 /* we've read in a full page, get a new one */
169 if (workspace->def_strm.avail_in == 0) {
170 if (workspace->def_strm.total_out > max_out)
171 break;
172
173 bytes_left = len - workspace->def_strm.total_in;
174 kunmap(in_page);
175 page_cache_release(in_page);
176
177 start += PAGE_CACHE_SIZE;
178 in_page = find_get_page(mapping,
179 start >> PAGE_CACHE_SHIFT);
180 data_in = kmap(in_page);
181 workspace->def_strm.avail_in = min(bytes_left,
182 PAGE_CACHE_SIZE);
183 workspace->def_strm.next_in = data_in;
184 }
185 }
186 workspace->def_strm.avail_in = 0;
187 ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
188 zlib_deflateEnd(&workspace->def_strm);
189
190 if (ret != Z_STREAM_END) {
191 ret = -1;
192 goto out;
193 }
194
195 if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
196 ret = -1;
197 goto out;
198 }
199
200 ret = 0;
201 *total_out = workspace->def_strm.total_out;
202 *total_in = workspace->def_strm.total_in;
203out:
204 *out_pages = nr_pages;
205 if (out_page)
206 kunmap(out_page);
207
208 if (in_page) {
209 kunmap(in_page);
210 page_cache_release(in_page);
211 }
212 return ret;
213}
214
215static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
216 u64 disk_start,
217 struct bio_vec *bvec,
218 int vcnt,
219 size_t srclen)
220{
221 struct workspace *workspace = list_entry(ws, struct workspace, list);
222 int ret = 0, ret2;
223 int wbits = MAX_WBITS;
224 char *data_in;
225 size_t total_out = 0;
226 unsigned long page_in_index = 0;
227 unsigned long page_out_index = 0;
228 unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
229 PAGE_CACHE_SIZE;
230 unsigned long buf_start;
231 unsigned long pg_offset;
232
233 data_in = kmap(pages_in[page_in_index]);
234 workspace->inf_strm.next_in = data_in;
235 workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
236 workspace->inf_strm.total_in = 0;
237
238 workspace->inf_strm.total_out = 0;
239 workspace->inf_strm.next_out = workspace->buf;
240 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
241 pg_offset = 0;
242
243 /* If it's deflate, and it's got no preset dictionary, then
244 we can tell zlib to skip the adler32 check. */
245 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
246 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
247 !(((data_in[0]<<8) + data_in[1]) % 31)) {
248
249 wbits = -((data_in[0] >> 4) + 8);
250 workspace->inf_strm.next_in += 2;
251 workspace->inf_strm.avail_in -= 2;
252 }
253
254 if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
255 printk(KERN_WARNING "inflateInit failed\n");
256 return -1;
257 }
258 while (workspace->inf_strm.total_in < srclen) {
259 ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
260 if (ret != Z_OK && ret != Z_STREAM_END)
261 break;
262
263 buf_start = total_out;
264 total_out = workspace->inf_strm.total_out;
265
266 /* we didn't make progress in this inflate call, we're done */
267 if (buf_start == total_out)
268 break;
269
270 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
271 total_out, disk_start,
272 bvec, vcnt,
273 &page_out_index, &pg_offset);
274 if (ret2 == 0) {
275 ret = 0;
276 goto done;
277 }
278
279 workspace->inf_strm.next_out = workspace->buf;
280 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
281
282 if (workspace->inf_strm.avail_in == 0) {
283 unsigned long tmp;
284 kunmap(pages_in[page_in_index]);
285 page_in_index++;
286 if (page_in_index >= total_pages_in) {
287 data_in = NULL;
288 break;
289 }
290 data_in = kmap(pages_in[page_in_index]);
291 workspace->inf_strm.next_in = data_in;
292 tmp = srclen - workspace->inf_strm.total_in;
293 workspace->inf_strm.avail_in = min(tmp,
294 PAGE_CACHE_SIZE);
295 }
296 }
297 if (ret != Z_STREAM_END)
298 ret = -1;
299 else
300 ret = 0;
301done:
302 zlib_inflateEnd(&workspace->inf_strm);
303 if (data_in)
304 kunmap(pages_in[page_in_index]);
305 return ret;
306}
307
308static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
309 struct page *dest_page,
310 unsigned long start_byte,
311 size_t srclen, size_t destlen)
312{
313 struct workspace *workspace = list_entry(ws, struct workspace, list);
314 int ret = 0;
315 int wbits = MAX_WBITS;
316 unsigned long bytes_left = destlen;
317 unsigned long total_out = 0;
318 char *kaddr;
319
320 workspace->inf_strm.next_in = data_in;
321 workspace->inf_strm.avail_in = srclen;
322 workspace->inf_strm.total_in = 0;
323
324 workspace->inf_strm.next_out = workspace->buf;
325 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
326 workspace->inf_strm.total_out = 0;
327 /* If it's deflate, and it's got no preset dictionary, then
328 we can tell zlib to skip the adler32 check. */
329 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
330 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
331 !(((data_in[0]<<8) + data_in[1]) % 31)) {
332
333 wbits = -((data_in[0] >> 4) + 8);
334 workspace->inf_strm.next_in += 2;
335 workspace->inf_strm.avail_in -= 2;
336 }
337
338 if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
339 printk(KERN_WARNING "inflateInit failed\n");
340 return -1;
341 }
342
343 while (bytes_left > 0) {
344 unsigned long buf_start;
345 unsigned long buf_offset;
346 unsigned long bytes;
347 unsigned long pg_offset = 0;
348
349 ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
350 if (ret != Z_OK && ret != Z_STREAM_END)
351 break;
352
353 buf_start = total_out;
354 total_out = workspace->inf_strm.total_out;
355
356 if (total_out == buf_start) {
357 ret = -1;
358 break;
359 }
360
361 if (total_out <= start_byte)
362 goto next;
363
364 if (total_out > start_byte && buf_start < start_byte)
365 buf_offset = start_byte - buf_start;
366 else
367 buf_offset = 0;
368
369 bytes = min(PAGE_CACHE_SIZE - pg_offset,
370 PAGE_CACHE_SIZE - buf_offset);
371 bytes = min(bytes, bytes_left);
372
373 kaddr = kmap_atomic(dest_page, KM_USER0);
374 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
375 kunmap_atomic(kaddr, KM_USER0);
376
377 pg_offset += bytes;
378 bytes_left -= bytes;
379next:
380 workspace->inf_strm.next_out = workspace->buf;
381 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
382 }
383
384 if (ret != Z_STREAM_END && bytes_left != 0)
385 ret = -1;
386 else
387 ret = 0;
388
389 zlib_inflateEnd(&workspace->inf_strm);
390 return ret;
391}
392
393struct btrfs_compress_op btrfs_zlib_compress = {
394 .alloc_workspace = zlib_alloc_workspace,
395 .free_workspace = zlib_free_workspace,
396 .compress_pages = zlib_compress_pages,
397 .decompress_biovec = zlib_decompress_biovec,
398 .decompress = zlib_decompress,
399};
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};