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Li Zefana6fa6fa2010-10-25 15:12:26 +08001/*
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
19#include <linux/kernel.h>
20#include <linux/slab.h>
21#include <linux/vmalloc.h>
22#include <linux/init.h>
23#include <linux/err.h>
24#include <linux/sched.h>
25#include <linux/pagemap.h>
26#include <linux/bio.h>
27#include <linux/lzo.h>
28#include "compression.h"
29
30#define LZO_LEN 4
31
32struct workspace {
33 void *mem;
Jie Liu3fb40372013-06-06 13:38:50 +000034 void *buf; /* where decompressed data goes */
35 void *cbuf; /* where compressed data goes */
Li Zefana6fa6fa2010-10-25 15:12:26 +080036 struct list_head list;
37};
38
39static void lzo_free_workspace(struct list_head *ws)
40{
41 struct workspace *workspace = list_entry(ws, struct workspace, list);
42
43 vfree(workspace->buf);
44 vfree(workspace->cbuf);
45 vfree(workspace->mem);
46 kfree(workspace);
47}
48
49static struct list_head *lzo_alloc_workspace(void)
50{
51 struct workspace *workspace;
52
53 workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
54 if (!workspace)
55 return ERR_PTR(-ENOMEM);
56
57 workspace->mem = vmalloc(LZO1X_MEM_COMPRESS);
58 workspace->buf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
59 workspace->cbuf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
60 if (!workspace->mem || !workspace->buf || !workspace->cbuf)
61 goto fail;
62
63 INIT_LIST_HEAD(&workspace->list);
64
65 return &workspace->list;
66fail:
67 lzo_free_workspace(&workspace->list);
68 return ERR_PTR(-ENOMEM);
69}
70
71static inline void write_compress_length(char *buf, size_t len)
72{
73 __le32 dlen;
74
75 dlen = cpu_to_le32(len);
76 memcpy(buf, &dlen, LZO_LEN);
77}
78
79static inline size_t read_compress_length(char *buf)
80{
81 __le32 dlen;
82
83 memcpy(&dlen, buf, LZO_LEN);
84 return le32_to_cpu(dlen);
85}
86
87static int lzo_compress_pages(struct list_head *ws,
88 struct address_space *mapping,
89 u64 start, unsigned long len,
90 struct page **pages,
91 unsigned long nr_dest_pages,
92 unsigned long *out_pages,
93 unsigned long *total_in,
94 unsigned long *total_out,
95 unsigned long max_out)
96{
97 struct workspace *workspace = list_entry(ws, struct workspace, list);
98 int ret = 0;
99 char *data_in;
100 char *cpage_out;
101 int nr_pages = 0;
102 struct page *in_page = NULL;
103 struct page *out_page = NULL;
104 unsigned long bytes_left;
105
106 size_t in_len;
107 size_t out_len;
108 char *buf;
109 unsigned long tot_in = 0;
110 unsigned long tot_out = 0;
111 unsigned long pg_bytes_left;
112 unsigned long out_offset;
113 unsigned long bytes;
114
115 *out_pages = 0;
116 *total_out = 0;
117 *total_in = 0;
118
119 in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
120 data_in = kmap(in_page);
121
122 /*
123 * store the size of all chunks of compressed data in
124 * the first 4 bytes
125 */
126 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
127 if (out_page == NULL) {
128 ret = -ENOMEM;
129 goto out;
130 }
131 cpage_out = kmap(out_page);
132 out_offset = LZO_LEN;
133 tot_out = LZO_LEN;
134 pages[0] = out_page;
135 nr_pages = 1;
136 pg_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
137
138 /* compress at most one page of data each time */
139 in_len = min(len, PAGE_CACHE_SIZE);
140 while (tot_in < len) {
141 ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
142 &out_len, workspace->mem);
143 if (ret != LZO_E_OK) {
144 printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
145 ret);
146 ret = -1;
147 goto out;
148 }
149
150 /* store the size of this chunk of compressed data */
151 write_compress_length(cpage_out + out_offset, out_len);
152 tot_out += LZO_LEN;
153 out_offset += LZO_LEN;
154 pg_bytes_left -= LZO_LEN;
155
156 tot_in += in_len;
157 tot_out += out_len;
158
159 /* copy bytes from the working buffer into the pages */
160 buf = workspace->cbuf;
161 while (out_len) {
162 bytes = min_t(unsigned long, pg_bytes_left, out_len);
163
164 memcpy(cpage_out + out_offset, buf, bytes);
165
166 out_len -= bytes;
167 pg_bytes_left -= bytes;
168 buf += bytes;
169 out_offset += bytes;
170
171 /*
172 * we need another page for writing out.
173 *
174 * Note if there's less than 4 bytes left, we just
175 * skip to a new page.
176 */
177 if ((out_len == 0 && pg_bytes_left < LZO_LEN) ||
178 pg_bytes_left == 0) {
179 if (pg_bytes_left) {
180 memset(cpage_out + out_offset, 0,
181 pg_bytes_left);
182 tot_out += pg_bytes_left;
183 }
184
185 /* we're done, don't allocate new page */
186 if (out_len == 0 && tot_in >= len)
187 break;
188
189 kunmap(out_page);
190 if (nr_pages == nr_dest_pages) {
191 out_page = NULL;
192 ret = -1;
193 goto out;
194 }
195
196 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
197 if (out_page == NULL) {
198 ret = -ENOMEM;
199 goto out;
200 }
201 cpage_out = kmap(out_page);
202 pages[nr_pages++] = out_page;
203
204 pg_bytes_left = PAGE_CACHE_SIZE;
205 out_offset = 0;
206 }
207 }
208
209 /* we're making it bigger, give up */
Stefan Agner59516f62013-07-01 20:33:39 +0200210 if (tot_in > 8192 && tot_in < tot_out) {
211 ret = -1;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800212 goto out;
Stefan Agner59516f62013-07-01 20:33:39 +0200213 }
Li Zefana6fa6fa2010-10-25 15:12:26 +0800214
215 /* we're all done */
216 if (tot_in >= len)
217 break;
218
219 if (tot_out > max_out)
220 break;
221
222 bytes_left = len - tot_in;
223 kunmap(in_page);
224 page_cache_release(in_page);
225
226 start += PAGE_CACHE_SIZE;
227 in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
228 data_in = kmap(in_page);
229 in_len = min(bytes_left, PAGE_CACHE_SIZE);
230 }
231
232 if (tot_out > tot_in)
233 goto out;
234
235 /* store the size of all chunks of compressed data */
236 cpage_out = kmap(pages[0]);
237 write_compress_length(cpage_out, tot_out);
238
239 kunmap(pages[0]);
240
241 ret = 0;
242 *total_out = tot_out;
243 *total_in = tot_in;
244out:
245 *out_pages = nr_pages;
246 if (out_page)
247 kunmap(out_page);
248
249 if (in_page) {
250 kunmap(in_page);
251 page_cache_release(in_page);
252 }
253
254 return ret;
255}
256
257static int lzo_decompress_biovec(struct list_head *ws,
258 struct page **pages_in,
259 u64 disk_start,
260 struct bio_vec *bvec,
261 int vcnt,
262 size_t srclen)
263{
264 struct workspace *workspace = list_entry(ws, struct workspace, list);
Li Zefan3a39c182010-11-08 15:22:19 +0800265 int ret = 0, ret2;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800266 char *data_in;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800267 unsigned long page_in_index = 0;
268 unsigned long page_out_index = 0;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800269 unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
270 PAGE_CACHE_SIZE;
271 unsigned long buf_start;
272 unsigned long buf_offset = 0;
273 unsigned long bytes;
274 unsigned long working_bytes;
275 unsigned long pg_offset;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800276
277 size_t in_len;
278 size_t out_len;
279 unsigned long in_offset;
280 unsigned long in_page_bytes_left;
281 unsigned long tot_in;
282 unsigned long tot_out;
283 unsigned long tot_len;
284 char *buf;
Li Zefanca9b6882011-02-16 06:06:41 +0000285 bool may_late_unmap, need_unmap;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800286
287 data_in = kmap(pages_in[0]);
288 tot_len = read_compress_length(data_in);
289
290 tot_in = LZO_LEN;
291 in_offset = LZO_LEN;
292 tot_len = min_t(size_t, srclen, tot_len);
293 in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
294
295 tot_out = 0;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800296 pg_offset = 0;
297
298 while (tot_in < tot_len) {
299 in_len = read_compress_length(data_in + in_offset);
300 in_page_bytes_left -= LZO_LEN;
301 in_offset += LZO_LEN;
302 tot_in += LZO_LEN;
303
304 tot_in += in_len;
305 working_bytes = in_len;
Li Zefanca9b6882011-02-16 06:06:41 +0000306 may_late_unmap = need_unmap = false;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800307
308 /* fast path: avoid using the working buffer */
309 if (in_page_bytes_left >= in_len) {
310 buf = data_in + in_offset;
311 bytes = in_len;
Li Zefanca9b6882011-02-16 06:06:41 +0000312 may_late_unmap = true;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800313 goto cont;
314 }
315
316 /* copy bytes from the pages into the working buffer */
317 buf = workspace->cbuf;
318 buf_offset = 0;
319 while (working_bytes) {
320 bytes = min(working_bytes, in_page_bytes_left);
321
322 memcpy(buf + buf_offset, data_in + in_offset, bytes);
323 buf_offset += bytes;
324cont:
325 working_bytes -= bytes;
326 in_page_bytes_left -= bytes;
327 in_offset += bytes;
328
329 /* check if we need to pick another page */
330 if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
331 || in_page_bytes_left == 0) {
332 tot_in += in_page_bytes_left;
333
334 if (working_bytes == 0 && tot_in >= tot_len)
335 break;
336
Li Zefanca9b6882011-02-16 06:06:41 +0000337 if (page_in_index + 1 >= total_pages_in) {
Li Zefana6fa6fa2010-10-25 15:12:26 +0800338 ret = -1;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800339 goto done;
340 }
Li Zefanca9b6882011-02-16 06:06:41 +0000341
342 if (may_late_unmap)
343 need_unmap = true;
344 else
345 kunmap(pages_in[page_in_index]);
346
347 data_in = kmap(pages_in[++page_in_index]);
Li Zefana6fa6fa2010-10-25 15:12:26 +0800348
349 in_page_bytes_left = PAGE_CACHE_SIZE;
350 in_offset = 0;
351 }
352 }
353
354 out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
355 ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
356 &out_len);
Li Zefanca9b6882011-02-16 06:06:41 +0000357 if (need_unmap)
358 kunmap(pages_in[page_in_index - 1]);
Li Zefana6fa6fa2010-10-25 15:12:26 +0800359 if (ret != LZO_E_OK) {
360 printk(KERN_WARNING "btrfs decompress failed\n");
361 ret = -1;
362 break;
363 }
364
Li Zefana6fa6fa2010-10-25 15:12:26 +0800365 buf_start = tot_out;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800366 tot_out += out_len;
367
Li Zefan3a39c182010-11-08 15:22:19 +0800368 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
369 tot_out, disk_start,
370 bvec, vcnt,
371 &page_out_index, &pg_offset);
372 if (ret2 == 0)
Li Zefana6fa6fa2010-10-25 15:12:26 +0800373 break;
Li Zefana6fa6fa2010-10-25 15:12:26 +0800374 }
375done:
Li Zefanca9b6882011-02-16 06:06:41 +0000376 kunmap(pages_in[page_in_index]);
Li Zefana6fa6fa2010-10-25 15:12:26 +0800377 return ret;
378}
379
380static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
381 struct page *dest_page,
382 unsigned long start_byte,
383 size_t srclen, size_t destlen)
384{
385 struct workspace *workspace = list_entry(ws, struct workspace, list);
386 size_t in_len;
387 size_t out_len;
388 size_t tot_len;
389 int ret = 0;
390 char *kaddr;
391 unsigned long bytes;
392
393 BUG_ON(srclen < LZO_LEN);
394
395 tot_len = read_compress_length(data_in);
396 data_in += LZO_LEN;
397
398 in_len = read_compress_length(data_in);
399 data_in += LZO_LEN;
400
401 out_len = PAGE_CACHE_SIZE;
402 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
403 if (ret != LZO_E_OK) {
404 printk(KERN_WARNING "btrfs decompress failed!\n");
405 ret = -1;
406 goto out;
407 }
408
409 if (out_len < start_byte) {
410 ret = -1;
411 goto out;
412 }
413
414 bytes = min_t(unsigned long, destlen, out_len - start_byte);
415
Cong Wang7ac687d2011-11-25 23:14:28 +0800416 kaddr = kmap_atomic(dest_page);
Li Zefana6fa6fa2010-10-25 15:12:26 +0800417 memcpy(kaddr, workspace->buf + start_byte, bytes);
Cong Wang7ac687d2011-11-25 23:14:28 +0800418 kunmap_atomic(kaddr);
Li Zefana6fa6fa2010-10-25 15:12:26 +0800419out:
420 return ret;
421}
422
423struct btrfs_compress_op btrfs_lzo_compress = {
424 .alloc_workspace = lzo_alloc_workspace,
425 .free_workspace = lzo_free_workspace,
426 .compress_pages = lzo_compress_pages,
427 .decompress_biovec = lzo_decompress_biovec,
428 .decompress = lzo_decompress,
429};