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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2008 Oracle. All rights reserved.
4 *
5 * Based on jffs2 zlib code:
6 * Copyright © 2001-2007 Red Hat, Inc.
7 * Created by David Woodhouse <dwmw2@infradead.org>
8 */
9
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/zlib.h>
13#include <linux/zutil.h>
14#include <linux/mm.h>
15#include <linux/init.h>
16#include <linux/err.h>
17#include <linux/sched.h>
18#include <linux/pagemap.h>
19#include <linux/bio.h>
20#include <linux/refcount.h>
21#include "compression.h"
22
23struct workspace {
24 z_stream strm;
25 char *buf;
26 struct list_head list;
27 int level;
28};
29
30static void zlib_free_workspace(struct list_head *ws)
31{
32 struct workspace *workspace = list_entry(ws, struct workspace, list);
33
34 kvfree(workspace->strm.workspace);
35 kfree(workspace->buf);
36 kfree(workspace);
37}
38
39static struct list_head *zlib_alloc_workspace(void)
40{
41 struct workspace *workspace;
42 int workspacesize;
43
44 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
45 if (!workspace)
46 return ERR_PTR(-ENOMEM);
47
48 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
49 zlib_inflate_workspacesize());
50 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
51 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
52 if (!workspace->strm.workspace || !workspace->buf)
53 goto fail;
54
55 INIT_LIST_HEAD(&workspace->list);
56
57 return &workspace->list;
58fail:
59 zlib_free_workspace(&workspace->list);
60 return ERR_PTR(-ENOMEM);
61}
62
63static int zlib_compress_pages(struct list_head *ws,
64 struct address_space *mapping,
65 u64 start,
66 struct page **pages,
67 unsigned long *out_pages,
68 unsigned long *total_in,
69 unsigned long *total_out)
70{
71 struct workspace *workspace = list_entry(ws, struct workspace, list);
72 int ret;
73 char *data_in;
74 char *cpage_out;
75 int nr_pages = 0;
76 struct page *in_page = NULL;
77 struct page *out_page = NULL;
78 unsigned long bytes_left;
79 unsigned long len = *total_out;
80 unsigned long nr_dest_pages = *out_pages;
81 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
82
83 *out_pages = 0;
84 *total_out = 0;
85 *total_in = 0;
86
87 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
88 pr_warn("BTRFS: deflateInit failed\n");
89 ret = -EIO;
90 goto out;
91 }
92
93 workspace->strm.total_in = 0;
94 workspace->strm.total_out = 0;
95
96 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
97 data_in = kmap(in_page);
98
99 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
100 if (out_page == NULL) {
101 ret = -ENOMEM;
102 goto out;
103 }
104 cpage_out = kmap(out_page);
105 pages[0] = out_page;
106 nr_pages = 1;
107
108 workspace->strm.next_in = data_in;
109 workspace->strm.next_out = cpage_out;
110 workspace->strm.avail_out = PAGE_SIZE;
111 workspace->strm.avail_in = min(len, PAGE_SIZE);
112
113 while (workspace->strm.total_in < len) {
114 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
115 if (ret != Z_OK) {
116 pr_debug("BTRFS: deflate in loop returned %d\n",
117 ret);
118 zlib_deflateEnd(&workspace->strm);
119 ret = -EIO;
120 goto out;
121 }
122
123 /* we're making it bigger, give up */
124 if (workspace->strm.total_in > 8192 &&
125 workspace->strm.total_in <
126 workspace->strm.total_out) {
127 ret = -E2BIG;
128 goto out;
129 }
130 /* we need another page for writing out. Test this
131 * before the total_in so we will pull in a new page for
132 * the stream end if required
133 */
134 if (workspace->strm.avail_out == 0) {
135 kunmap(out_page);
136 if (nr_pages == nr_dest_pages) {
137 out_page = NULL;
138 ret = -E2BIG;
139 goto out;
140 }
141 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
142 if (out_page == NULL) {
143 ret = -ENOMEM;
144 goto out;
145 }
146 cpage_out = kmap(out_page);
147 pages[nr_pages] = out_page;
148 nr_pages++;
149 workspace->strm.avail_out = PAGE_SIZE;
150 workspace->strm.next_out = cpage_out;
151 }
152 /* we're all done */
153 if (workspace->strm.total_in >= len)
154 break;
155
156 /* we've read in a full page, get a new one */
157 if (workspace->strm.avail_in == 0) {
158 if (workspace->strm.total_out > max_out)
159 break;
160
161 bytes_left = len - workspace->strm.total_in;
162 kunmap(in_page);
163 put_page(in_page);
164
165 start += PAGE_SIZE;
166 in_page = find_get_page(mapping,
167 start >> PAGE_SHIFT);
168 data_in = kmap(in_page);
169 workspace->strm.avail_in = min(bytes_left,
170 PAGE_SIZE);
171 workspace->strm.next_in = data_in;
172 }
173 }
174 workspace->strm.avail_in = 0;
175 ret = zlib_deflate(&workspace->strm, Z_FINISH);
176 zlib_deflateEnd(&workspace->strm);
177
178 if (ret != Z_STREAM_END) {
179 ret = -EIO;
180 goto out;
181 }
182
183 if (workspace->strm.total_out >= workspace->strm.total_in) {
184 ret = -E2BIG;
185 goto out;
186 }
187
188 ret = 0;
189 *total_out = workspace->strm.total_out;
190 *total_in = workspace->strm.total_in;
191out:
192 *out_pages = nr_pages;
193 if (out_page)
194 kunmap(out_page);
195
196 if (in_page) {
197 kunmap(in_page);
198 put_page(in_page);
199 }
200 return ret;
201}
202
203static int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
204{
205 struct workspace *workspace = list_entry(ws, struct workspace, list);
206 int ret = 0, ret2;
207 int wbits = MAX_WBITS;
208 char *data_in;
209 size_t total_out = 0;
210 unsigned long page_in_index = 0;
211 size_t srclen = cb->compressed_len;
212 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
213 unsigned long buf_start;
214 struct page **pages_in = cb->compressed_pages;
215 u64 disk_start = cb->start;
216 struct bio *orig_bio = cb->orig_bio;
217
218 data_in = kmap(pages_in[page_in_index]);
219 workspace->strm.next_in = data_in;
220 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
221 workspace->strm.total_in = 0;
222
223 workspace->strm.total_out = 0;
224 workspace->strm.next_out = workspace->buf;
225 workspace->strm.avail_out = PAGE_SIZE;
226
227 /* If it's deflate, and it's got no preset dictionary, then
228 we can tell zlib to skip the adler32 check. */
229 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
230 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
231 !(((data_in[0]<<8) + data_in[1]) % 31)) {
232
233 wbits = -((data_in[0] >> 4) + 8);
234 workspace->strm.next_in += 2;
235 workspace->strm.avail_in -= 2;
236 }
237
238 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
239 pr_warn("BTRFS: inflateInit failed\n");
240 kunmap(pages_in[page_in_index]);
241 return -EIO;
242 }
243 while (workspace->strm.total_in < srclen) {
244 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
245 if (ret != Z_OK && ret != Z_STREAM_END)
246 break;
247
248 buf_start = total_out;
249 total_out = workspace->strm.total_out;
250
251 /* we didn't make progress in this inflate call, we're done */
252 if (buf_start == total_out)
253 break;
254
255 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
256 total_out, disk_start,
257 orig_bio);
258 if (ret2 == 0) {
259 ret = 0;
260 goto done;
261 }
262
263 workspace->strm.next_out = workspace->buf;
264 workspace->strm.avail_out = PAGE_SIZE;
265
266 if (workspace->strm.avail_in == 0) {
267 unsigned long tmp;
268 kunmap(pages_in[page_in_index]);
269 page_in_index++;
270 if (page_in_index >= total_pages_in) {
271 data_in = NULL;
272 break;
273 }
274 data_in = kmap(pages_in[page_in_index]);
275 workspace->strm.next_in = data_in;
276 tmp = srclen - workspace->strm.total_in;
277 workspace->strm.avail_in = min(tmp,
278 PAGE_SIZE);
279 }
280 }
281 if (ret != Z_STREAM_END)
282 ret = -EIO;
283 else
284 ret = 0;
285done:
286 zlib_inflateEnd(&workspace->strm);
287 if (data_in)
288 kunmap(pages_in[page_in_index]);
289 if (!ret)
290 zero_fill_bio(orig_bio);
291 return ret;
292}
293
294static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
295 struct page *dest_page,
296 unsigned long start_byte,
297 size_t srclen, size_t destlen)
298{
299 struct workspace *workspace = list_entry(ws, struct workspace, list);
300 int ret = 0;
301 int wbits = MAX_WBITS;
302 unsigned long bytes_left;
303 unsigned long total_out = 0;
304 unsigned long pg_offset = 0;
305 char *kaddr;
306
307 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
308 bytes_left = destlen;
309
310 workspace->strm.next_in = data_in;
311 workspace->strm.avail_in = srclen;
312 workspace->strm.total_in = 0;
313
314 workspace->strm.next_out = workspace->buf;
315 workspace->strm.avail_out = PAGE_SIZE;
316 workspace->strm.total_out = 0;
317 /* If it's deflate, and it's got no preset dictionary, then
318 we can tell zlib to skip the adler32 check. */
319 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
320 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
321 !(((data_in[0]<<8) + data_in[1]) % 31)) {
322
323 wbits = -((data_in[0] >> 4) + 8);
324 workspace->strm.next_in += 2;
325 workspace->strm.avail_in -= 2;
326 }
327
328 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
329 pr_warn("BTRFS: inflateInit failed\n");
330 return -EIO;
331 }
332
333 while (bytes_left > 0) {
334 unsigned long buf_start;
335 unsigned long buf_offset;
336 unsigned long bytes;
337
338 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
339 if (ret != Z_OK && ret != Z_STREAM_END)
340 break;
341
342 buf_start = total_out;
343 total_out = workspace->strm.total_out;
344
345 if (total_out == buf_start) {
346 ret = -EIO;
347 break;
348 }
349
350 if (total_out <= start_byte)
351 goto next;
352
353 if (total_out > start_byte && buf_start < start_byte)
354 buf_offset = start_byte - buf_start;
355 else
356 buf_offset = 0;
357
358 bytes = min(PAGE_SIZE - pg_offset,
359 PAGE_SIZE - buf_offset);
360 bytes = min(bytes, bytes_left);
361
362 kaddr = kmap_atomic(dest_page);
363 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
364 kunmap_atomic(kaddr);
365
366 pg_offset += bytes;
367 bytes_left -= bytes;
368next:
369 workspace->strm.next_out = workspace->buf;
370 workspace->strm.avail_out = PAGE_SIZE;
371 }
372
373 if (ret != Z_STREAM_END && bytes_left != 0)
374 ret = -EIO;
375 else
376 ret = 0;
377
378 zlib_inflateEnd(&workspace->strm);
379
380 /*
381 * this should only happen if zlib returned fewer bytes than we
382 * expected. btrfs_get_block is responsible for zeroing from the
383 * end of the inline extent (destlen) to the end of the page
384 */
385 if (pg_offset < destlen) {
386 kaddr = kmap_atomic(dest_page);
387 memset(kaddr + pg_offset, 0, destlen - pg_offset);
388 kunmap_atomic(kaddr);
389 }
390 return ret;
391}
392
393static void zlib_set_level(struct list_head *ws, unsigned int type)
394{
395 struct workspace *workspace = list_entry(ws, struct workspace, list);
396 unsigned level = (type & 0xF0) >> 4;
397
398 if (level > 9)
399 level = 9;
400
401 workspace->level = level > 0 ? level : 3;
402}
403
404const struct btrfs_compress_op btrfs_zlib_compress = {
405 .alloc_workspace = zlib_alloc_workspace,
406 .free_workspace = zlib_free_workspace,
407 .compress_pages = zlib_compress_pages,
408 .decompress_bio = zlib_decompress_bio,
409 .decompress = zlib_decompress,
410 .set_level = zlib_set_level,
411};