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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 "btrfs_inode.h"
22#include "compression.h"
23#include "fs.h"
24#include "subpage.h"
25
26/* workspace buffer size for s390 zlib hardware support */
27#define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
28
29struct workspace {
30 z_stream strm;
31 char *buf;
32 unsigned int buf_size;
33 struct list_head list;
34 int level;
35};
36
37static struct workspace_manager wsm;
38
39struct list_head *zlib_get_workspace(unsigned int level)
40{
41 struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
42 struct workspace *workspace = list_entry(ws, struct workspace, list);
43
44 workspace->level = level;
45
46 return ws;
47}
48
49void zlib_free_workspace(struct list_head *ws)
50{
51 struct workspace *workspace = list_entry(ws, struct workspace, list);
52
53 kvfree(workspace->strm.workspace);
54 kfree(workspace->buf);
55 kfree(workspace);
56}
57
58struct list_head *zlib_alloc_workspace(unsigned int level)
59{
60 struct workspace *workspace;
61 int workspacesize;
62
63 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
64 if (!workspace)
65 return ERR_PTR(-ENOMEM);
66
67 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
68 zlib_inflate_workspacesize());
69 workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN);
70 workspace->level = level;
71 workspace->buf = NULL;
72 /*
73 * In case of s390 zlib hardware support, allocate lager workspace
74 * buffer. If allocator fails, fall back to a single page buffer.
75 */
76 if (zlib_deflate_dfltcc_enabled()) {
77 workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
78 __GFP_NOMEMALLOC | __GFP_NORETRY |
79 __GFP_NOWARN | GFP_NOIO);
80 workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
81 }
82 if (!workspace->buf) {
83 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
84 workspace->buf_size = PAGE_SIZE;
85 }
86 if (!workspace->strm.workspace || !workspace->buf)
87 goto fail;
88
89 INIT_LIST_HEAD(&workspace->list);
90
91 return &workspace->list;
92fail:
93 zlib_free_workspace(&workspace->list);
94 return ERR_PTR(-ENOMEM);
95}
96
97int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
98 u64 start, struct folio **folios, unsigned long *out_folios,
99 unsigned long *total_in, unsigned long *total_out)
100{
101 struct workspace *workspace = list_entry(ws, struct workspace, list);
102 int ret;
103 char *data_in = NULL;
104 char *cfolio_out;
105 int nr_folios = 0;
106 struct folio *in_folio = NULL;
107 struct folio *out_folio = NULL;
108 unsigned long bytes_left;
109 unsigned int in_buf_folios;
110 unsigned long len = *total_out;
111 unsigned long nr_dest_folios = *out_folios;
112 const unsigned long max_out = nr_dest_folios * PAGE_SIZE;
113 const u64 orig_end = start + len;
114
115 *out_folios = 0;
116 *total_out = 0;
117 *total_in = 0;
118
119 ret = zlib_deflateInit(&workspace->strm, workspace->level);
120 if (unlikely(ret != Z_OK)) {
121 struct btrfs_inode *inode = BTRFS_I(mapping->host);
122
123 btrfs_err(inode->root->fs_info,
124 "zlib compression init failed, error %d root %llu inode %llu offset %llu",
125 ret, btrfs_root_id(inode->root), btrfs_ino(inode), start);
126 ret = -EIO;
127 goto out;
128 }
129
130 workspace->strm.total_in = 0;
131 workspace->strm.total_out = 0;
132
133 out_folio = btrfs_alloc_compr_folio();
134 if (out_folio == NULL) {
135 ret = -ENOMEM;
136 goto out;
137 }
138 cfolio_out = folio_address(out_folio);
139 folios[0] = out_folio;
140 nr_folios = 1;
141
142 workspace->strm.next_in = workspace->buf;
143 workspace->strm.avail_in = 0;
144 workspace->strm.next_out = cfolio_out;
145 workspace->strm.avail_out = PAGE_SIZE;
146
147 while (workspace->strm.total_in < len) {
148 /*
149 * Get next input pages and copy the contents to
150 * the workspace buffer if required.
151 */
152 if (workspace->strm.avail_in == 0) {
153 bytes_left = len - workspace->strm.total_in;
154 in_buf_folios = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
155 workspace->buf_size / PAGE_SIZE);
156 if (in_buf_folios > 1) {
157 int i;
158
159 /* S390 hardware acceleration path, not subpage. */
160 ASSERT(!btrfs_is_subpage(
161 inode_to_fs_info(mapping->host),
162 mapping));
163 for (i = 0; i < in_buf_folios; i++) {
164 if (data_in) {
165 kunmap_local(data_in);
166 folio_put(in_folio);
167 data_in = NULL;
168 }
169 ret = btrfs_compress_filemap_get_folio(mapping,
170 start, &in_folio);
171 if (ret < 0)
172 goto out;
173 data_in = kmap_local_folio(in_folio, 0);
174 copy_page(workspace->buf + i * PAGE_SIZE,
175 data_in);
176 start += PAGE_SIZE;
177 }
178 workspace->strm.next_in = workspace->buf;
179 workspace->strm.avail_in = min(bytes_left,
180 in_buf_folios << PAGE_SHIFT);
181 } else {
182 unsigned int pg_off;
183 unsigned int cur_len;
184
185 if (data_in) {
186 kunmap_local(data_in);
187 folio_put(in_folio);
188 data_in = NULL;
189 }
190 ret = btrfs_compress_filemap_get_folio(mapping,
191 start, &in_folio);
192 if (ret < 0)
193 goto out;
194 pg_off = offset_in_page(start);
195 cur_len = btrfs_calc_input_length(orig_end, start);
196 data_in = kmap_local_folio(in_folio, pg_off);
197 start += cur_len;
198 workspace->strm.next_in = data_in;
199 workspace->strm.avail_in = cur_len;
200 }
201 }
202
203 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
204 if (unlikely(ret != Z_OK)) {
205 struct btrfs_inode *inode = BTRFS_I(mapping->host);
206
207 btrfs_warn(inode->root->fs_info,
208 "zlib compression failed, error %d root %llu inode %llu offset %llu",
209 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
210 start);
211 zlib_deflateEnd(&workspace->strm);
212 ret = -EIO;
213 goto out;
214 }
215
216 /* we're making it bigger, give up */
217 if (workspace->strm.total_in > 8192 &&
218 workspace->strm.total_in <
219 workspace->strm.total_out) {
220 ret = -E2BIG;
221 goto out;
222 }
223 /* we need another page for writing out. Test this
224 * before the total_in so we will pull in a new page for
225 * the stream end if required
226 */
227 if (workspace->strm.avail_out == 0) {
228 if (nr_folios == nr_dest_folios) {
229 ret = -E2BIG;
230 goto out;
231 }
232 out_folio = btrfs_alloc_compr_folio();
233 if (out_folio == NULL) {
234 ret = -ENOMEM;
235 goto out;
236 }
237 cfolio_out = folio_address(out_folio);
238 folios[nr_folios] = out_folio;
239 nr_folios++;
240 workspace->strm.avail_out = PAGE_SIZE;
241 workspace->strm.next_out = cfolio_out;
242 }
243 /* we're all done */
244 if (workspace->strm.total_in >= len)
245 break;
246 if (workspace->strm.total_out > max_out)
247 break;
248 }
249 workspace->strm.avail_in = 0;
250 /*
251 * Call deflate with Z_FINISH flush parameter providing more output
252 * space but no more input data, until it returns with Z_STREAM_END.
253 */
254 while (ret != Z_STREAM_END) {
255 ret = zlib_deflate(&workspace->strm, Z_FINISH);
256 if (ret == Z_STREAM_END)
257 break;
258 if (ret != Z_OK && ret != Z_BUF_ERROR) {
259 zlib_deflateEnd(&workspace->strm);
260 ret = -EIO;
261 goto out;
262 } else if (workspace->strm.avail_out == 0) {
263 /* Get another folio for the stream end. */
264 if (nr_folios == nr_dest_folios) {
265 ret = -E2BIG;
266 goto out;
267 }
268 out_folio = btrfs_alloc_compr_folio();
269 if (out_folio == NULL) {
270 ret = -ENOMEM;
271 goto out;
272 }
273 cfolio_out = folio_address(out_folio);
274 folios[nr_folios] = out_folio;
275 nr_folios++;
276 workspace->strm.avail_out = PAGE_SIZE;
277 workspace->strm.next_out = cfolio_out;
278 }
279 }
280 zlib_deflateEnd(&workspace->strm);
281
282 if (workspace->strm.total_out >= workspace->strm.total_in) {
283 ret = -E2BIG;
284 goto out;
285 }
286
287 ret = 0;
288 *total_out = workspace->strm.total_out;
289 *total_in = workspace->strm.total_in;
290out:
291 *out_folios = nr_folios;
292 if (data_in) {
293 kunmap_local(data_in);
294 folio_put(in_folio);
295 }
296
297 return ret;
298}
299
300int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
301{
302 struct workspace *workspace = list_entry(ws, struct workspace, list);
303 int ret = 0, ret2;
304 int wbits = MAX_WBITS;
305 char *data_in;
306 size_t total_out = 0;
307 unsigned long folio_in_index = 0;
308 size_t srclen = cb->compressed_len;
309 unsigned long total_folios_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
310 unsigned long buf_start;
311 struct folio **folios_in = cb->compressed_folios;
312
313 data_in = kmap_local_folio(folios_in[folio_in_index], 0);
314 workspace->strm.next_in = data_in;
315 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
316 workspace->strm.total_in = 0;
317
318 workspace->strm.total_out = 0;
319 workspace->strm.next_out = workspace->buf;
320 workspace->strm.avail_out = workspace->buf_size;
321
322 /* If it's deflate, and it's got no preset dictionary, then
323 we can tell zlib to skip the adler32 check. */
324 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
325 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
326 !(((data_in[0]<<8) + data_in[1]) % 31)) {
327
328 wbits = -((data_in[0] >> 4) + 8);
329 workspace->strm.next_in += 2;
330 workspace->strm.avail_in -= 2;
331 }
332
333 ret = zlib_inflateInit2(&workspace->strm, wbits);
334 if (unlikely(ret != Z_OK)) {
335 struct btrfs_inode *inode = cb->bbio.inode;
336
337 kunmap_local(data_in);
338 btrfs_err(inode->root->fs_info,
339 "zlib decompression init failed, error %d root %llu inode %llu offset %llu",
340 ret, btrfs_root_id(inode->root), btrfs_ino(inode), cb->start);
341 return -EIO;
342 }
343 while (workspace->strm.total_in < srclen) {
344 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
345 if (ret != Z_OK && ret != Z_STREAM_END)
346 break;
347
348 buf_start = total_out;
349 total_out = workspace->strm.total_out;
350
351 /* we didn't make progress in this inflate call, we're done */
352 if (buf_start == total_out)
353 break;
354
355 ret2 = btrfs_decompress_buf2page(workspace->buf,
356 total_out - buf_start, cb, buf_start);
357 if (ret2 == 0) {
358 ret = 0;
359 goto done;
360 }
361
362 workspace->strm.next_out = workspace->buf;
363 workspace->strm.avail_out = workspace->buf_size;
364
365 if (workspace->strm.avail_in == 0) {
366 unsigned long tmp;
367 kunmap_local(data_in);
368 folio_in_index++;
369 if (folio_in_index >= total_folios_in) {
370 data_in = NULL;
371 break;
372 }
373 data_in = kmap_local_folio(folios_in[folio_in_index], 0);
374 workspace->strm.next_in = data_in;
375 tmp = srclen - workspace->strm.total_in;
376 workspace->strm.avail_in = min(tmp, PAGE_SIZE);
377 }
378 }
379 if (unlikely(ret != Z_STREAM_END)) {
380 btrfs_err(cb->bbio.inode->root->fs_info,
381 "zlib decompression failed, error %d root %llu inode %llu offset %llu",
382 ret, btrfs_root_id(cb->bbio.inode->root),
383 btrfs_ino(cb->bbio.inode), cb->start);
384 ret = -EIO;
385 } else {
386 ret = 0;
387 }
388done:
389 zlib_inflateEnd(&workspace->strm);
390 if (data_in)
391 kunmap_local(data_in);
392 return ret;
393}
394
395int zlib_decompress(struct list_head *ws, const u8 *data_in,
396 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
397 size_t destlen)
398{
399 struct workspace *workspace = list_entry(ws, struct workspace, list);
400 int ret = 0;
401 int wbits = MAX_WBITS;
402 unsigned long to_copy;
403
404 workspace->strm.next_in = data_in;
405 workspace->strm.avail_in = srclen;
406 workspace->strm.total_in = 0;
407
408 workspace->strm.next_out = workspace->buf;
409 workspace->strm.avail_out = workspace->buf_size;
410 workspace->strm.total_out = 0;
411 /* If it's deflate, and it's got no preset dictionary, then
412 we can tell zlib to skip the adler32 check. */
413 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
414 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
415 !(((data_in[0]<<8) + data_in[1]) % 31)) {
416
417 wbits = -((data_in[0] >> 4) + 8);
418 workspace->strm.next_in += 2;
419 workspace->strm.avail_in -= 2;
420 }
421
422 ret = zlib_inflateInit2(&workspace->strm, wbits);
423 if (unlikely(ret != Z_OK)) {
424 struct btrfs_inode *inode = folio_to_inode(dest_folio);
425
426 btrfs_err(inode->root->fs_info,
427 "zlib decompression init failed, error %d root %llu inode %llu offset %llu",
428 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
429 folio_pos(dest_folio));
430 return -EIO;
431 }
432
433 /*
434 * Everything (in/out buf) should be at most one sector, there should
435 * be no need to switch any input/output buffer.
436 */
437 ret = zlib_inflate(&workspace->strm, Z_FINISH);
438 to_copy = min(workspace->strm.total_out, destlen);
439 if (ret != Z_STREAM_END)
440 goto out;
441
442 memcpy_to_folio(dest_folio, dest_pgoff, workspace->buf, to_copy);
443
444out:
445 if (unlikely(to_copy != destlen)) {
446 struct btrfs_inode *inode = folio_to_inode(dest_folio);
447
448 btrfs_err(inode->root->fs_info,
449"zlib decompression failed, error %d root %llu inode %llu offset %llu decompressed %lu expected %zu",
450 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
451 folio_pos(dest_folio), to_copy, destlen);
452 ret = -EIO;
453 } else {
454 ret = 0;
455 }
456
457 zlib_inflateEnd(&workspace->strm);
458
459 if (unlikely(to_copy < destlen))
460 folio_zero_range(dest_folio, dest_pgoff + to_copy, destlen - to_copy);
461 return ret;
462}
463
464const struct btrfs_compress_op btrfs_zlib_compress = {
465 .workspace_manager = &wsm,
466 .max_level = 9,
467 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
468};
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};