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-rw-r--r--fs/btrfs/lzo.c509
1 files changed, 509 insertions, 0 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
new file mode 100644
index 000000000000..523b144e2aec
--- /dev/null
+++ b/fs/btrfs/lzo.c
@@ -0,0 +1,509 @@
1/*
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;
34 void *buf; /* where compressed data goes */
35 void *cbuf; /* where decompressed data goes */
36 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 */
210 if (tot_in > 8192 && tot_in < tot_out)
211 goto out;
212
213 /* we're all done */
214 if (tot_in >= len)
215 break;
216
217 if (tot_out > max_out)
218 break;
219
220 bytes_left = len - tot_in;
221 kunmap(in_page);
222 page_cache_release(in_page);
223
224 start += PAGE_CACHE_SIZE;
225 in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
226 data_in = kmap(in_page);
227 in_len = min(bytes_left, PAGE_CACHE_SIZE);
228 }
229
230 if (tot_out > tot_in)
231 goto out;
232
233 /* store the size of all chunks of compressed data */
234 cpage_out = kmap(pages[0]);
235 write_compress_length(cpage_out, tot_out);
236
237 kunmap(pages[0]);
238
239 ret = 0;
240 *total_out = tot_out;
241 *total_in = tot_in;
242out:
243 *out_pages = nr_pages;
244 if (out_page)
245 kunmap(out_page);
246
247 if (in_page) {
248 kunmap(in_page);
249 page_cache_release(in_page);
250 }
251
252 return ret;
253}
254
255static int lzo_decompress_biovec(struct list_head *ws,
256 struct page **pages_in,
257 u64 disk_start,
258 struct bio_vec *bvec,
259 int vcnt,
260 size_t srclen)
261{
262 struct workspace *workspace = list_entry(ws, struct workspace, list);
263 int ret = 0;
264 char *data_in;
265 unsigned long page_bytes_left;
266 unsigned long page_in_index = 0;
267 unsigned long page_out_index = 0;
268 struct page *page_out;
269 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;
276 unsigned long start_byte;
277 unsigned long current_buf_start;
278 char *kaddr;
279
280 size_t in_len;
281 size_t out_len;
282 unsigned long in_offset;
283 unsigned long in_page_bytes_left;
284 unsigned long tot_in;
285 unsigned long tot_out;
286 unsigned long tot_len;
287 char *buf;
288
289 data_in = kmap(pages_in[0]);
290 tot_len = read_compress_length(data_in);
291
292 tot_in = LZO_LEN;
293 in_offset = LZO_LEN;
294 tot_len = min_t(size_t, srclen, tot_len);
295 in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
296
297 tot_out = 0;
298 page_out = bvec[0].bv_page;
299 page_bytes_left = PAGE_CACHE_SIZE;
300 pg_offset = 0;
301
302 while (tot_in < tot_len) {
303 in_len = read_compress_length(data_in + in_offset);
304 in_page_bytes_left -= LZO_LEN;
305 in_offset += LZO_LEN;
306 tot_in += LZO_LEN;
307
308 tot_in += in_len;
309 working_bytes = in_len;
310
311 /* fast path: avoid using the working buffer */
312 if (in_page_bytes_left >= in_len) {
313 buf = data_in + in_offset;
314 bytes = in_len;
315 goto cont;
316 }
317
318 /* copy bytes from the pages into the working buffer */
319 buf = workspace->cbuf;
320 buf_offset = 0;
321 while (working_bytes) {
322 bytes = min(working_bytes, in_page_bytes_left);
323
324 memcpy(buf + buf_offset, data_in + in_offset, bytes);
325 buf_offset += bytes;
326cont:
327 working_bytes -= bytes;
328 in_page_bytes_left -= bytes;
329 in_offset += bytes;
330
331 /* check if we need to pick another page */
332 if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
333 || in_page_bytes_left == 0) {
334 tot_in += in_page_bytes_left;
335
336 if (working_bytes == 0 && tot_in >= tot_len)
337 break;
338
339 kunmap(pages_in[page_in_index]);
340 page_in_index++;
341 if (page_in_index >= total_pages_in) {
342 ret = -1;
343 data_in = NULL;
344 goto done;
345 }
346 data_in = kmap(pages_in[page_in_index]);
347
348 in_page_bytes_left = PAGE_CACHE_SIZE;
349 in_offset = 0;
350 }
351 }
352
353 out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
354 ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
355 &out_len);
356 if (ret != LZO_E_OK) {
357 printk(KERN_WARNING "btrfs decompress failed\n");
358 ret = -1;
359 break;
360 }
361
362 /*
363 * buf start is the byte offset we're of the start of
364 * our workspace buffer
365 */
366 buf_start = tot_out;
367
368 /* tot_out is the last byte of the workspace buffer */
369 tot_out += out_len;
370
371 working_bytes = tot_out - buf_start;
372
373 /*
374 * start_byte is the first byte of the page we're currently
375 * copying into relative to the start of the compressed data.
376 */
377 start_byte = page_offset(page_out) - disk_start;
378
379 if (working_bytes == 0) {
380 /* we didn't make progress in this inflate
381 * call, we're done
382 */
383 break;
384 }
385
386 /* we haven't yet hit data corresponding to this page */
387 if (tot_out <= start_byte)
388 continue;
389
390 /*
391 * the start of the data we care about is offset into
392 * the middle of our working buffer
393 */
394 if (tot_out > start_byte && buf_start < start_byte) {
395 buf_offset = start_byte - buf_start;
396 working_bytes -= buf_offset;
397 } else {
398 buf_offset = 0;
399 }
400 current_buf_start = buf_start;
401
402 /* copy bytes from the working buffer into the pages */
403 while (working_bytes > 0) {
404 bytes = min(PAGE_CACHE_SIZE - pg_offset,
405 PAGE_CACHE_SIZE - buf_offset);
406 bytes = min(bytes, working_bytes);
407 kaddr = kmap_atomic(page_out, KM_USER0);
408 memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
409 bytes);
410 kunmap_atomic(kaddr, KM_USER0);
411 flush_dcache_page(page_out);
412
413 pg_offset += bytes;
414 page_bytes_left -= bytes;
415 buf_offset += bytes;
416 working_bytes -= bytes;
417 current_buf_start += bytes;
418
419 /* check if we need to pick another page */
420 if (page_bytes_left == 0) {
421 page_out_index++;
422 if (page_out_index >= vcnt) {
423 ret = 0;
424 goto done;
425 }
426
427 page_out = bvec[page_out_index].bv_page;
428 pg_offset = 0;
429 page_bytes_left = PAGE_CACHE_SIZE;
430 start_byte = page_offset(page_out) - disk_start;
431
432 /*
433 * make sure our new page is covered by this
434 * working buffer
435 */
436 if (tot_out <= start_byte)
437 break;
438
439 /* the next page in the biovec might not
440 * be adjacent to the last page, but it
441 * might still be found inside this working
442 * buffer. bump our offset pointer
443 */
444 if (tot_out > start_byte &&
445 current_buf_start < start_byte) {
446 buf_offset = start_byte - buf_start;
447 working_bytes = tot_out - start_byte;
448 current_buf_start = buf_start +
449 buf_offset;
450 }
451 }
452 }
453 }
454done:
455 if (data_in)
456 kunmap(pages_in[page_in_index]);
457 return ret;
458}
459
460static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
461 struct page *dest_page,
462 unsigned long start_byte,
463 size_t srclen, size_t destlen)
464{
465 struct workspace *workspace = list_entry(ws, struct workspace, list);
466 size_t in_len;
467 size_t out_len;
468 size_t tot_len;
469 int ret = 0;
470 char *kaddr;
471 unsigned long bytes;
472
473 BUG_ON(srclen < LZO_LEN);
474
475 tot_len = read_compress_length(data_in);
476 data_in += LZO_LEN;
477
478 in_len = read_compress_length(data_in);
479 data_in += LZO_LEN;
480
481 out_len = PAGE_CACHE_SIZE;
482 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
483 if (ret != LZO_E_OK) {
484 printk(KERN_WARNING "btrfs decompress failed!\n");
485 ret = -1;
486 goto out;
487 }
488
489 if (out_len < start_byte) {
490 ret = -1;
491 goto out;
492 }
493
494 bytes = min_t(unsigned long, destlen, out_len - start_byte);
495
496 kaddr = kmap_atomic(dest_page, KM_USER0);
497 memcpy(kaddr, workspace->buf + start_byte, bytes);
498 kunmap_atomic(kaddr, KM_USER0);
499out:
500 return ret;
501}
502
503struct btrfs_compress_op btrfs_lzo_compress = {
504 .alloc_workspace = lzo_alloc_workspace,
505 .free_workspace = lzo_free_workspace,
506 .compress_pages = lzo_compress_pages,
507 .decompress_biovec = lzo_decompress_biovec,
508 .decompress = lzo_decompress,
509};
generated by cgit v1.2.2 (git 2.25.0) at 2026-01-03 10:52:37 -0500