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6#include <linux/kernel.h>
7#include <linux/slab.h>
8#include <linux/mm.h>
9#include <linux/init.h>
10#include <linux/err.h>
11#include <linux/sched.h>
12#include <linux/pagemap.h>
13#include <linux/bio.h>
14#include <linux/lzo.h>
15#include <linux/refcount.h>
16#include "compression.h"
17
18#define LZO_LEN 4
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57struct workspace {
58 void *mem;
59 void *buf;
60 void *cbuf;
61 struct list_head list;
62};
63
64static struct workspace_manager wsm;
65
66void lzo_free_workspace(struct list_head *ws)
67{
68 struct workspace *workspace = list_entry(ws, struct workspace, list);
69
70 kvfree(workspace->buf);
71 kvfree(workspace->cbuf);
72 kvfree(workspace->mem);
73 kfree(workspace);
74}
75
76struct list_head *lzo_alloc_workspace(unsigned int level)
77{
78 struct workspace *workspace;
79
80 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
81 if (!workspace)
82 return ERR_PTR(-ENOMEM);
83
84 workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
85 workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
86 workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
87 if (!workspace->mem || !workspace->buf || !workspace->cbuf)
88 goto fail;
89
90 INIT_LIST_HEAD(&workspace->list);
91
92 return &workspace->list;
93fail:
94 lzo_free_workspace(&workspace->list);
95 return ERR_PTR(-ENOMEM);
96}
97
98static inline void write_compress_length(char *buf, size_t len)
99{
100 __le32 dlen;
101
102 dlen = cpu_to_le32(len);
103 memcpy(buf, &dlen, LZO_LEN);
104}
105
106static inline size_t read_compress_length(const char *buf)
107{
108 __le32 dlen;
109
110 memcpy(&dlen, buf, LZO_LEN);
111 return le32_to_cpu(dlen);
112}
113
114int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
115 u64 start, struct page **pages, unsigned long *out_pages,
116 unsigned long *total_in, unsigned long *total_out)
117{
118 struct workspace *workspace = list_entry(ws, struct workspace, list);
119 int ret = 0;
120 char *data_in;
121 char *cpage_out;
122 int nr_pages = 0;
123 struct page *in_page = NULL;
124 struct page *out_page = NULL;
125 unsigned long bytes_left;
126 unsigned long len = *total_out;
127 unsigned long nr_dest_pages = *out_pages;
128 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
129 size_t in_len;
130 size_t out_len;
131 char *buf;
132 unsigned long tot_in = 0;
133 unsigned long tot_out = 0;
134 unsigned long pg_bytes_left;
135 unsigned long out_offset;
136 unsigned long bytes;
137
138 *out_pages = 0;
139 *total_out = 0;
140 *total_in = 0;
141
142 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
143 data_in = kmap(in_page);
144
145
146
147
148
149 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
150 if (out_page == NULL) {
151 ret = -ENOMEM;
152 goto out;
153 }
154 cpage_out = kmap(out_page);
155 out_offset = LZO_LEN;
156 tot_out = LZO_LEN;
157 pages[0] = out_page;
158 nr_pages = 1;
159 pg_bytes_left = PAGE_SIZE - LZO_LEN;
160
161
162 in_len = min(len, PAGE_SIZE);
163 while (tot_in < len) {
164 ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
165 &out_len, workspace->mem);
166 if (ret != LZO_E_OK) {
167 pr_debug("BTRFS: lzo in loop returned %d\n",
168 ret);
169 ret = -EIO;
170 goto out;
171 }
172
173
174 write_compress_length(cpage_out + out_offset, out_len);
175 tot_out += LZO_LEN;
176 out_offset += LZO_LEN;
177 pg_bytes_left -= LZO_LEN;
178
179 tot_in += in_len;
180 tot_out += out_len;
181
182
183 buf = workspace->cbuf;
184 while (out_len) {
185 bytes = min_t(unsigned long, pg_bytes_left, out_len);
186
187 memcpy(cpage_out + out_offset, buf, bytes);
188
189 out_len -= bytes;
190 pg_bytes_left -= bytes;
191 buf += bytes;
192 out_offset += bytes;
193
194
195
196
197
198
199
200 if ((out_len == 0 && pg_bytes_left < LZO_LEN) ||
201 pg_bytes_left == 0) {
202 if (pg_bytes_left) {
203 memset(cpage_out + out_offset, 0,
204 pg_bytes_left);
205 tot_out += pg_bytes_left;
206 }
207
208
209 if (out_len == 0 && tot_in >= len)
210 break;
211
212 kunmap(out_page);
213 if (nr_pages == nr_dest_pages) {
214 out_page = NULL;
215 ret = -E2BIG;
216 goto out;
217 }
218
219 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
220 if (out_page == NULL) {
221 ret = -ENOMEM;
222 goto out;
223 }
224 cpage_out = kmap(out_page);
225 pages[nr_pages++] = out_page;
226
227 pg_bytes_left = PAGE_SIZE;
228 out_offset = 0;
229 }
230 }
231
232
233 if (tot_in > 8192 && tot_in < tot_out) {
234 ret = -E2BIG;
235 goto out;
236 }
237
238
239 if (tot_in >= len)
240 break;
241
242 if (tot_out > max_out)
243 break;
244
245 bytes_left = len - tot_in;
246 kunmap(in_page);
247 put_page(in_page);
248
249 start += PAGE_SIZE;
250 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
251 data_in = kmap(in_page);
252 in_len = min(bytes_left, PAGE_SIZE);
253 }
254
255 if (tot_out >= tot_in) {
256 ret = -E2BIG;
257 goto out;
258 }
259
260
261 cpage_out = kmap(pages[0]);
262 write_compress_length(cpage_out, tot_out);
263
264 kunmap(pages[0]);
265
266 ret = 0;
267 *total_out = tot_out;
268 *total_in = tot_in;
269out:
270 *out_pages = nr_pages;
271 if (out_page)
272 kunmap(out_page);
273
274 if (in_page) {
275 kunmap(in_page);
276 put_page(in_page);
277 }
278
279 return ret;
280}
281
282int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
283{
284 struct workspace *workspace = list_entry(ws, struct workspace, list);
285 int ret = 0, ret2;
286 char *data_in;
287 unsigned long page_in_index = 0;
288 size_t srclen = cb->compressed_len;
289 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
290 unsigned long buf_start;
291 unsigned long buf_offset = 0;
292 unsigned long bytes;
293 unsigned long working_bytes;
294 size_t in_len;
295 size_t out_len;
296 const size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
297 unsigned long in_offset;
298 unsigned long in_page_bytes_left;
299 unsigned long tot_in;
300 unsigned long tot_out;
301 unsigned long tot_len;
302 char *buf;
303 bool may_late_unmap, need_unmap;
304 struct page **pages_in = cb->compressed_pages;
305 u64 disk_start = cb->start;
306 struct bio *orig_bio = cb->orig_bio;
307
308 data_in = kmap(pages_in[0]);
309 tot_len = read_compress_length(data_in);
310
311
312
313
314
315
316
317
318 if (tot_len > min_t(size_t, BTRFS_MAX_COMPRESSED, srclen) ||
319 tot_len < srclen - PAGE_SIZE) {
320 ret = -EUCLEAN;
321 goto done;
322 }
323
324 tot_in = LZO_LEN;
325 in_offset = LZO_LEN;
326 in_page_bytes_left = PAGE_SIZE - LZO_LEN;
327
328 tot_out = 0;
329
330 while (tot_in < tot_len) {
331 in_len = read_compress_length(data_in + in_offset);
332 in_page_bytes_left -= LZO_LEN;
333 in_offset += LZO_LEN;
334 tot_in += LZO_LEN;
335
336
337
338
339
340
341
342 if (in_len > max_segment_len || tot_in + in_len > tot_len) {
343 ret = -EUCLEAN;
344 goto done;
345 }
346
347 tot_in += in_len;
348 working_bytes = in_len;
349 may_late_unmap = need_unmap = false;
350
351
352 if (in_page_bytes_left >= in_len) {
353 buf = data_in + in_offset;
354 bytes = in_len;
355 may_late_unmap = true;
356 goto cont;
357 }
358
359
360 buf = workspace->cbuf;
361 buf_offset = 0;
362 while (working_bytes) {
363 bytes = min(working_bytes, in_page_bytes_left);
364
365 memcpy(buf + buf_offset, data_in + in_offset, bytes);
366 buf_offset += bytes;
367cont:
368 working_bytes -= bytes;
369 in_page_bytes_left -= bytes;
370 in_offset += bytes;
371
372
373 if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
374 || in_page_bytes_left == 0) {
375 tot_in += in_page_bytes_left;
376
377 if (working_bytes == 0 && tot_in >= tot_len)
378 break;
379
380 if (page_in_index + 1 >= total_pages_in) {
381 ret = -EIO;
382 goto done;
383 }
384
385 if (may_late_unmap)
386 need_unmap = true;
387 else
388 kunmap(pages_in[page_in_index]);
389
390 data_in = kmap(pages_in[++page_in_index]);
391
392 in_page_bytes_left = PAGE_SIZE;
393 in_offset = 0;
394 }
395 }
396
397 out_len = max_segment_len;
398 ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
399 &out_len);
400 if (need_unmap)
401 kunmap(pages_in[page_in_index - 1]);
402 if (ret != LZO_E_OK) {
403 pr_warn("BTRFS: decompress failed\n");
404 ret = -EIO;
405 break;
406 }
407
408 buf_start = tot_out;
409 tot_out += out_len;
410
411 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
412 tot_out, disk_start, orig_bio);
413 if (ret2 == 0)
414 break;
415 }
416done:
417 kunmap(pages_in[page_in_index]);
418 if (!ret)
419 zero_fill_bio(orig_bio);
420 return ret;
421}
422
423int lzo_decompress(struct list_head *ws, unsigned char *data_in,
424 struct page *dest_page, unsigned long start_byte, size_t srclen,
425 size_t destlen)
426{
427 struct workspace *workspace = list_entry(ws, struct workspace, list);
428 size_t in_len;
429 size_t out_len;
430 size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
431 int ret = 0;
432 char *kaddr;
433 unsigned long bytes;
434
435 if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2)
436 return -EUCLEAN;
437
438 in_len = read_compress_length(data_in);
439 if (in_len != srclen)
440 return -EUCLEAN;
441 data_in += LZO_LEN;
442
443 in_len = read_compress_length(data_in);
444 if (in_len != srclen - LZO_LEN * 2) {
445 ret = -EUCLEAN;
446 goto out;
447 }
448 data_in += LZO_LEN;
449
450 out_len = PAGE_SIZE;
451 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
452 if (ret != LZO_E_OK) {
453 pr_warn("BTRFS: decompress failed!\n");
454 ret = -EIO;
455 goto out;
456 }
457
458 if (out_len < start_byte) {
459 ret = -EIO;
460 goto out;
461 }
462
463
464
465
466
467 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
468 bytes = min_t(unsigned long, destlen, out_len - start_byte);
469
470 kaddr = kmap_atomic(dest_page);
471 memcpy(kaddr, workspace->buf + start_byte, bytes);
472
473
474
475
476
477
478 if (bytes < destlen)
479 memset(kaddr+bytes, 0, destlen-bytes);
480 kunmap_atomic(kaddr);
481out:
482 return ret;
483}
484
485const struct btrfs_compress_op btrfs_lzo_compress = {
486 .workspace_manager = &wsm,
487 .max_level = 1,
488 .default_level = 1,
489};
490