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a6fa6fae LZ |
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 | ||
32 | struct workspace { | |
33 | void *mem; | |
3fb40375 JL |
34 | void *buf; /* where decompressed data goes */ |
35 | void *cbuf; /* where compressed data goes */ | |
a6fa6fae LZ |
36 | struct list_head list; |
37 | }; | |
38 | ||
39 | static 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 | ||
49 | static 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; | |
66 | fail: | |
67 | lzo_free_workspace(&workspace->list); | |
68 | return ERR_PTR(-ENOMEM); | |
69 | } | |
70 | ||
71 | static 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 | ||
79 | static 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 | ||
87 | static 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) { | |
efe120a0 | 144 | printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n", |
a6fa6fae LZ |
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 */ | |
59516f60 SA |
210 | if (tot_in > 8192 && tot_in < tot_out) { |
211 | ret = -1; | |
a6fa6fae | 212 | goto out; |
59516f60 | 213 | } |
a6fa6fae LZ |
214 | |
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; | |
244 | out: | |
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 | ||
257 | static 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); | |
3a39c18d | 265 | int ret = 0, ret2; |
a6fa6fae | 266 | char *data_in; |
a6fa6fae LZ |
267 | unsigned long page_in_index = 0; |
268 | unsigned long page_out_index = 0; | |
a6fa6fae LZ |
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; | |
a6fa6fae LZ |
276 | |
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; | |
ca9b688c | 285 | bool may_late_unmap, need_unmap; |
a6fa6fae LZ |
286 | |
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; | |
a6fa6fae LZ |
296 | 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; | |
ca9b688c | 306 | may_late_unmap = need_unmap = false; |
a6fa6fae LZ |
307 | |
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; | |
ca9b688c | 312 | may_late_unmap = true; |
a6fa6fae LZ |
313 | 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; | |
324 | cont: | |
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 | ||
ca9b688c | 337 | if (page_in_index + 1 >= total_pages_in) { |
a6fa6fae | 338 | ret = -1; |
a6fa6fae LZ |
339 | goto done; |
340 | } | |
ca9b688c LZ |
341 | |
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]); | |
a6fa6fae LZ |
348 | |
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); | |
ca9b688c LZ |
357 | if (need_unmap) |
358 | kunmap(pages_in[page_in_index - 1]); | |
a6fa6fae | 359 | if (ret != LZO_E_OK) { |
efe120a0 | 360 | printk(KERN_WARNING "BTRFS: decompress failed\n"); |
a6fa6fae LZ |
361 | ret = -1; |
362 | break; | |
363 | } | |
364 | ||
a6fa6fae | 365 | buf_start = tot_out; |
a6fa6fae LZ |
366 | tot_out += out_len; |
367 | ||
3a39c18d LZ |
368 | 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) | |
a6fa6fae | 373 | break; |
a6fa6fae LZ |
374 | } |
375 | done: | |
ca9b688c | 376 | kunmap(pages_in[page_in_index]); |
a6fa6fae LZ |
377 | return ret; |
378 | } | |
379 | ||
380 | static 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) { | |
efe120a0 | 404 | printk(KERN_WARNING "BTRFS: decompress failed!\n"); |
a6fa6fae LZ |
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 | ||
7ac687d9 | 416 | kaddr = kmap_atomic(dest_page); |
a6fa6fae | 417 | memcpy(kaddr, workspace->buf + start_byte, bytes); |
7ac687d9 | 418 | kunmap_atomic(kaddr); |
a6fa6fae LZ |
419 | out: |
420 | return ret; | |
421 | } | |
422 | ||
423 | struct 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 | }; |