1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2008 Oracle. All rights reserved.
4 *
5 * Based on jffs2 zlib code:
6 * Copyright © 2001-2007 Red Hat, Inc.
7 * Created by David Woodhouse <dwmw2@infradead.org>
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/zlib.h>
13 #include <linux/zutil.h>
14 #include <linux/mm.h>
15 #include <linux/init.h>
16 #include <linux/err.h>
17 #include <linux/sched.h>
18 #include <linux/pagemap.h>
19 #include <linux/bio.h>
20 #include <linux/refcount.h>
21 #include "compression.h"
22
23 /* workspace buffer size for s390 zlib hardware support */
24 #define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
25
26 struct workspace {
27 z_stream strm;
28 char *buf;
29 unsigned int buf_size;
30 struct list_head list;
31 int level;
32 };
33
34 static struct workspace_manager wsm;
35
zlib_get_workspace(unsigned int level)36 struct list_head *zlib_get_workspace(unsigned int level)
37 {
38 struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
39 struct workspace *workspace = list_entry(ws, struct workspace, list);
40
41 workspace->level = level;
42
43 return ws;
44 }
45
zlib_free_workspace(struct list_head * ws)46 void zlib_free_workspace(struct list_head *ws)
47 {
48 struct workspace *workspace = list_entry(ws, struct workspace, list);
49
50 kvfree(workspace->strm.workspace);
51 kfree(workspace->buf);
52 kfree(workspace);
53 }
54
zlib_alloc_workspace(unsigned int level)55 struct list_head *zlib_alloc_workspace(unsigned int level)
56 {
57 struct workspace *workspace;
58 int workspacesize;
59
60 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
61 if (!workspace)
62 return ERR_PTR(-ENOMEM);
63
64 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
65 zlib_inflate_workspacesize());
66 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
67 workspace->level = level;
68 workspace->buf = NULL;
69 /*
70 * In case of s390 zlib hardware support, allocate lager workspace
71 * buffer. If allocator fails, fall back to a single page buffer.
72 */
73 if (zlib_deflate_dfltcc_enabled()) {
74 workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
75 __GFP_NOMEMALLOC | __GFP_NORETRY |
76 __GFP_NOWARN | GFP_NOIO);
77 workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
78 }
79 if (!workspace->buf) {
80 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
81 workspace->buf_size = PAGE_SIZE;
82 }
83 if (!workspace->strm.workspace || !workspace->buf)
84 goto fail;
85
86 INIT_LIST_HEAD(&workspace->list);
87
88 return &workspace->list;
89 fail:
90 zlib_free_workspace(&workspace->list);
91 return ERR_PTR(-ENOMEM);
92 }
93
zlib_compress_pages(struct list_head * ws,struct address_space * mapping,u64 start,struct page ** pages,unsigned long * out_pages,unsigned long * total_in,unsigned long * total_out)94 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
95 u64 start, struct page **pages, unsigned long *out_pages,
96 unsigned long *total_in, unsigned long *total_out)
97 {
98 struct workspace *workspace = list_entry(ws, struct workspace, list);
99 int ret;
100 char *data_in = NULL;
101 char *cpage_out;
102 int nr_pages = 0;
103 struct page *in_page = NULL;
104 struct page *out_page = NULL;
105 unsigned long bytes_left;
106 unsigned int in_buf_pages;
107 unsigned long len = *total_out;
108 unsigned long nr_dest_pages = *out_pages;
109 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
110
111 *out_pages = 0;
112 *total_out = 0;
113 *total_in = 0;
114
115 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
116 pr_warn("BTRFS: deflateInit failed\n");
117 ret = -EIO;
118 goto out;
119 }
120
121 workspace->strm.total_in = 0;
122 workspace->strm.total_out = 0;
123
124 out_page = alloc_page(GFP_NOFS);
125 if (out_page == NULL) {
126 ret = -ENOMEM;
127 goto out;
128 }
129 cpage_out = page_address(out_page);
130 pages[0] = out_page;
131 nr_pages = 1;
132
133 workspace->strm.next_in = workspace->buf;
134 workspace->strm.avail_in = 0;
135 workspace->strm.next_out = cpage_out;
136 workspace->strm.avail_out = PAGE_SIZE;
137
138 while (workspace->strm.total_in < len) {
139 /*
140 * Get next input pages and copy the contents to
141 * the workspace buffer if required.
142 */
143 if (workspace->strm.avail_in == 0) {
144 bytes_left = len - workspace->strm.total_in;
145 in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
146 workspace->buf_size / PAGE_SIZE);
147 if (in_buf_pages > 1) {
148 int i;
149
150 for (i = 0; i < in_buf_pages; i++) {
151 if (data_in) {
152 kunmap_local(data_in);
153 put_page(in_page);
154 }
155 in_page = find_get_page(mapping,
156 start >> PAGE_SHIFT);
157 data_in = kmap_local_page(in_page);
158 memcpy(workspace->buf + i * PAGE_SIZE,
159 data_in, PAGE_SIZE);
160 start += PAGE_SIZE;
161 }
162 workspace->strm.next_in = workspace->buf;
163 } else {
164 if (data_in) {
165 kunmap_local(data_in);
166 put_page(in_page);
167 }
168 in_page = find_get_page(mapping,
169 start >> PAGE_SHIFT);
170 data_in = kmap_local_page(in_page);
171 start += PAGE_SIZE;
172 workspace->strm.next_in = data_in;
173 }
174 workspace->strm.avail_in = min(bytes_left,
175 (unsigned long) workspace->buf_size);
176 }
177
178 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
179 if (ret != Z_OK) {
180 pr_debug("BTRFS: deflate in loop returned %d\n",
181 ret);
182 zlib_deflateEnd(&workspace->strm);
183 ret = -EIO;
184 goto out;
185 }
186
187 /* we're making it bigger, give up */
188 if (workspace->strm.total_in > 8192 &&
189 workspace->strm.total_in <
190 workspace->strm.total_out) {
191 ret = -E2BIG;
192 goto out;
193 }
194 /* we need another page for writing out. Test this
195 * before the total_in so we will pull in a new page for
196 * the stream end if required
197 */
198 if (workspace->strm.avail_out == 0) {
199 if (nr_pages == nr_dest_pages) {
200 ret = -E2BIG;
201 goto out;
202 }
203 out_page = alloc_page(GFP_NOFS);
204 if (out_page == NULL) {
205 ret = -ENOMEM;
206 goto out;
207 }
208 cpage_out = page_address(out_page);
209 pages[nr_pages] = out_page;
210 nr_pages++;
211 workspace->strm.avail_out = PAGE_SIZE;
212 workspace->strm.next_out = cpage_out;
213 }
214 /* we're all done */
215 if (workspace->strm.total_in >= len)
216 break;
217 if (workspace->strm.total_out > max_out)
218 break;
219 }
220 workspace->strm.avail_in = 0;
221 /*
222 * Call deflate with Z_FINISH flush parameter providing more output
223 * space but no more input data, until it returns with Z_STREAM_END.
224 */
225 while (ret != Z_STREAM_END) {
226 ret = zlib_deflate(&workspace->strm, Z_FINISH);
227 if (ret == Z_STREAM_END)
228 break;
229 if (ret != Z_OK && ret != Z_BUF_ERROR) {
230 zlib_deflateEnd(&workspace->strm);
231 ret = -EIO;
232 goto out;
233 } else if (workspace->strm.avail_out == 0) {
234 /* get another page for the stream end */
235 if (nr_pages == nr_dest_pages) {
236 ret = -E2BIG;
237 goto out;
238 }
239 out_page = alloc_page(GFP_NOFS);
240 if (out_page == NULL) {
241 ret = -ENOMEM;
242 goto out;
243 }
244 cpage_out = page_address(out_page);
245 pages[nr_pages] = out_page;
246 nr_pages++;
247 workspace->strm.avail_out = PAGE_SIZE;
248 workspace->strm.next_out = cpage_out;
249 }
250 }
251 zlib_deflateEnd(&workspace->strm);
252
253 if (workspace->strm.total_out >= workspace->strm.total_in) {
254 ret = -E2BIG;
255 goto out;
256 }
257
258 ret = 0;
259 *total_out = workspace->strm.total_out;
260 *total_in = workspace->strm.total_in;
261 out:
262 *out_pages = nr_pages;
263 if (data_in) {
264 kunmap_local(data_in);
265 put_page(in_page);
266 }
267
268 return ret;
269 }
270
zlib_decompress_bio(struct list_head * ws,struct compressed_bio * cb)271 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
272 {
273 struct workspace *workspace = list_entry(ws, struct workspace, list);
274 int ret = 0, ret2;
275 int wbits = MAX_WBITS;
276 char *data_in;
277 size_t total_out = 0;
278 unsigned long page_in_index = 0;
279 size_t srclen = cb->compressed_len;
280 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
281 unsigned long buf_start;
282 struct page **pages_in = cb->compressed_pages;
283
284 data_in = kmap_local_page(pages_in[page_in_index]);
285 workspace->strm.next_in = data_in;
286 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
287 workspace->strm.total_in = 0;
288
289 workspace->strm.total_out = 0;
290 workspace->strm.next_out = workspace->buf;
291 workspace->strm.avail_out = workspace->buf_size;
292
293 /* If it's deflate, and it's got no preset dictionary, then
294 we can tell zlib to skip the adler32 check. */
295 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
296 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
297 !(((data_in[0]<<8) + data_in[1]) % 31)) {
298
299 wbits = -((data_in[0] >> 4) + 8);
300 workspace->strm.next_in += 2;
301 workspace->strm.avail_in -= 2;
302 }
303
304 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
305 pr_warn("BTRFS: inflateInit failed\n");
306 kunmap_local(data_in);
307 return -EIO;
308 }
309 while (workspace->strm.total_in < srclen) {
310 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
311 if (ret != Z_OK && ret != Z_STREAM_END)
312 break;
313
314 buf_start = total_out;
315 total_out = workspace->strm.total_out;
316
317 /* we didn't make progress in this inflate call, we're done */
318 if (buf_start == total_out)
319 break;
320
321 ret2 = btrfs_decompress_buf2page(workspace->buf,
322 total_out - buf_start, cb, buf_start);
323 if (ret2 == 0) {
324 ret = 0;
325 goto done;
326 }
327
328 workspace->strm.next_out = workspace->buf;
329 workspace->strm.avail_out = workspace->buf_size;
330
331 if (workspace->strm.avail_in == 0) {
332 unsigned long tmp;
333 kunmap_local(data_in);
334 page_in_index++;
335 if (page_in_index >= total_pages_in) {
336 data_in = NULL;
337 break;
338 }
339 data_in = kmap_local_page(pages_in[page_in_index]);
340 workspace->strm.next_in = data_in;
341 tmp = srclen - workspace->strm.total_in;
342 workspace->strm.avail_in = min(tmp, PAGE_SIZE);
343 }
344 }
345 if (ret != Z_STREAM_END)
346 ret = -EIO;
347 else
348 ret = 0;
349 done:
350 zlib_inflateEnd(&workspace->strm);
351 if (data_in)
352 kunmap_local(data_in);
353 if (!ret)
354 zero_fill_bio(cb->orig_bio);
355 return ret;
356 }
357
zlib_decompress(struct list_head * ws,unsigned char * data_in,struct page * dest_page,unsigned long start_byte,size_t srclen,size_t destlen)358 int zlib_decompress(struct list_head *ws, unsigned char *data_in,
359 struct page *dest_page, unsigned long start_byte, size_t srclen,
360 size_t destlen)
361 {
362 struct workspace *workspace = list_entry(ws, struct workspace, list);
363 int ret = 0;
364 int wbits = MAX_WBITS;
365 unsigned long bytes_left;
366 unsigned long total_out = 0;
367 unsigned long pg_offset = 0;
368
369 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
370 bytes_left = destlen;
371
372 workspace->strm.next_in = data_in;
373 workspace->strm.avail_in = srclen;
374 workspace->strm.total_in = 0;
375
376 workspace->strm.next_out = workspace->buf;
377 workspace->strm.avail_out = workspace->buf_size;
378 workspace->strm.total_out = 0;
379 /* If it's deflate, and it's got no preset dictionary, then
380 we can tell zlib to skip the adler32 check. */
381 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
382 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
383 !(((data_in[0]<<8) + data_in[1]) % 31)) {
384
385 wbits = -((data_in[0] >> 4) + 8);
386 workspace->strm.next_in += 2;
387 workspace->strm.avail_in -= 2;
388 }
389
390 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
391 pr_warn("BTRFS: inflateInit failed\n");
392 return -EIO;
393 }
394
395 while (bytes_left > 0) {
396 unsigned long buf_start;
397 unsigned long buf_offset;
398 unsigned long bytes;
399
400 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
401 if (ret != Z_OK && ret != Z_STREAM_END)
402 break;
403
404 buf_start = total_out;
405 total_out = workspace->strm.total_out;
406
407 if (total_out == buf_start) {
408 ret = -EIO;
409 break;
410 }
411
412 if (total_out <= start_byte)
413 goto next;
414
415 if (total_out > start_byte && buf_start < start_byte)
416 buf_offset = start_byte - buf_start;
417 else
418 buf_offset = 0;
419
420 bytes = min(PAGE_SIZE - pg_offset,
421 PAGE_SIZE - (buf_offset % PAGE_SIZE));
422 bytes = min(bytes, bytes_left);
423
424 memcpy_to_page(dest_page, pg_offset,
425 workspace->buf + buf_offset, bytes);
426
427 pg_offset += bytes;
428 bytes_left -= bytes;
429 next:
430 workspace->strm.next_out = workspace->buf;
431 workspace->strm.avail_out = workspace->buf_size;
432 }
433
434 if (ret != Z_STREAM_END && bytes_left != 0)
435 ret = -EIO;
436 else
437 ret = 0;
438
439 zlib_inflateEnd(&workspace->strm);
440
441 /*
442 * this should only happen if zlib returned fewer bytes than we
443 * expected. btrfs_get_block is responsible for zeroing from the
444 * end of the inline extent (destlen) to the end of the page
445 */
446 if (pg_offset < destlen) {
447 memzero_page(dest_page, pg_offset, destlen - pg_offset);
448 }
449 return ret;
450 }
451
452 const struct btrfs_compress_op btrfs_zlib_compress = {
453 .workspace_manager = &wsm,
454 .max_level = 9,
455 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
456 };
457